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Shang Y, He J, Qiu J, Hu S, Wang X, Zhang T, Wang W, Yuan X, Xu J, Li F. The tolerance of two marine diatoms to diurnal pH fluctuation under dynamic light condition and ocean acidification scenario. MARINE ENVIRONMENTAL RESEARCH 2024; 196:106425. [PMID: 38442592 DOI: 10.1016/j.marenvres.2024.106425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/29/2024] [Accepted: 02/25/2024] [Indexed: 03/07/2024]
Abstract
Coastal waters undergo dynamic changes in seawater carbonate chemistry due to natural and anthropogenic factors. Despite this, our current understanding of how coastal phytoplankton respond to fluctuating pH is limited. In the present study, we investigated the physiological responses of two coastal diatoms Thalassiosira pseudonana and Thalassiosira weissflogii to seawater acidification and diurnally fluctuating pH under natural solar irradiance. Seawater acidification did not significantly impact the growth, maximum and effective quantum yield of PSII, and photosynthetic rates of the two species. However, it did increase the maximum relative electron transport rate of T. weissflogii by 11%. Overall, fluctuating pH had neutral or positive effects on both species. It enhanced the light-saturated photosynthetic rate of T. weissflogii by 20% compared to cells grown under seawater acidification condition. Results from the short-term pH exposure experiment revealed that the photosynthetic rates of both species remained unaffected by acute pH changes, indicating their tolerance to varying pH. Nevertheless, it is crucial to consider dynamic pH when predicting changes in primary production in coastal waters, given the interplay of various environmental drivers.
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Affiliation(s)
- Yu Shang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Jie He
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Jingmin Qiu
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Siyu Hu
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Xin Wang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Tianzhi Zhang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Weili Wang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Xiaoyue Yuan
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Juntian Xu
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Futian Li
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China; Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China; Marine Resources Development Institute of Jiangsu, Jiangsu Ocean University, Lianyungang, China.
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Sun X, Zhang M, Liu J, Hui G, Chen X, Feng C. The Art of Exploring Diatom Biosilica Biomaterials: From Biofabrication Perspective. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2304695. [PMID: 38044309 PMCID: PMC10853744 DOI: 10.1002/advs.202304695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/18/2023] [Indexed: 12/05/2023]
Abstract
Diatom is a common single-cell microalgae with large species and huge biomass. Diatom biosilica (DB), the shell of diatom, is a natural inorganic material with a micro-nanoporous structure. Its unique hierarchical porous structure gives it great application potential in drug delivery, hemostat materials, and biosensors, etc. However, the structural diversity of DB determines its different biological functions. Screening hundreds of thousands of diatom species for structural features of DB that meet application requirements is like looking for a needle in a seaway. And the chemical modification methods lack effective means to control the micro-nanoporous structure of DB. The formation of DB is a typical biomineralization process, and its structural characteristics are affected by external environmental conditions, genes, and other factors. This allows to manipulate the micro-nanostructure of DB through biological regulation method, thereby transforming the screening mode of the structure function of DB from a needle in a seaway to biofabrication mode. This review focuses on the formation, biological modification, functional activity of DB structure, and its application in biomaterials field, providing regulatory strategies and research idea of DB from the perspective of biofabrication. It will also maximize the possibility of using DB as biological materials.
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Affiliation(s)
- Xiaojie Sun
- College of Marine Life ScienceOcean University of China5# Yushan RoadQingdaoShandong Province266003China
| | - Mengxue Zhang
- College of Marine Life ScienceOcean University of China5# Yushan RoadQingdaoShandong Province266003China
| | - Jinfeng Liu
- College of Marine Life ScienceOcean University of China5# Yushan RoadQingdaoShandong Province266003China
- Department of StomatologyQingdao Women and Children’s Hospital, QingdaoQingdao266034China
| | - Guangyan Hui
- Department of StomatologyQingdao Special Servicemen Recuperation Center of PLA NavyNo.18 Yueyang RoadQingdaoShandong Province266071China
| | - Xiguang Chen
- College of Marine Life ScienceOcean University of China5# Yushan RoadQingdaoShandong Province266003China
- Sanya Oceanographic Institute, Ocean University of ChinaYazhou Bay Science & Technology CityFloor 7, Building 1, Yonyou Industrial ParkSanyaHainan Province572024P. R. China
- Laoshan Laboratory1# Wenhai RoadQingdaoShandong Province266000China
| | - Chao Feng
- College of Marine Life ScienceOcean University of China5# Yushan RoadQingdaoShandong Province266003China
- Sanya Oceanographic Institute, Ocean University of ChinaYazhou Bay Science & Technology CityFloor 7, Building 1, Yonyou Industrial ParkSanyaHainan Province572024P. R. China
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Shimakawa G, Yashiro E, Matsuda Y. Mapping of subcellular local pH in the marine diatom Phaeodactylum tricornutum. PHYSIOLOGIA PLANTARUM 2023; 175:e14086. [PMID: 38148208 DOI: 10.1111/ppl.14086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/30/2023] [Accepted: 10/30/2023] [Indexed: 12/28/2023]
Abstract
Diatoms are one of the most important phytoplankton on Earth. They comprise at least ten thousand species and contribute to up to 20% of the global primary production. Because of serial endosymbiotic events and horizontal gene transfers, diatoms have developed a "secondary plastid" bounded by four membranes containing a large phase-separated compartment, termed the pyrenoid. However, the physiological significance of this unique chloroplast morphology is poorly understood. Characterization of fundamental physiological parameters such as local pH in various subcellular compartments should facilitate a greater understanding of the physiological roles of the unique structure of the secondary plastid. A promising method to estimate local pH is the in situ expression of the pH-sensitive green fluorescent protein. Here, we first developed the molecular tool for the mapping of in situ local pH in the diatom Phaeodactylum tricornutum by heterologously expressing pHluorin2 in the cytosol, periplastidal compartment (PPC; the space in between two sets of outer and inner chloroplast envelopes), chloroplast stroma, and the pyrenoid matrix. Our data suggested that PPC and the pyrenoid matrix are more acidic than the adjacent areas, the cytosol and the chloroplast stroma. Finally, absolute pH values at each compartment were estimated from the ratiometric fluorescence of a recombinant pHluorin2 protein, giving pH values of approximately 7.9, 6.8, 8.0, and 7.5 respectively, for the cytosol, PPC, stroma, and pyrenoid of the P. tricornutum cells, indicating the occurrence of pH gradients and the associated electrochemical potentials at their boundary.
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Affiliation(s)
- Ginga Shimakawa
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Hyogo, Japan
| | - Emi Yashiro
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Hyogo, Japan
| | - Yusuke Matsuda
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Hyogo, Japan
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Petrucciani A, Moretti P, Ortore MG, Norici A. Integrative effects of morphology, silicification, and light on diatom vertical movements. FRONTIERS IN PLANT SCIENCE 2023; 14:1143998. [PMID: 37056507 PMCID: PMC10087530 DOI: 10.3389/fpls.2023.1143998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 03/06/2023] [Indexed: 06/19/2023]
Abstract
Diatoms represent the most abundant and diversified class of primary producers in present oceans; their distinctive trait is the ability to incorporate silicic acid in a silica outer shell called frustule. Numerous adaptative functions are ascribed to frustules, including the control of vertical movements through the water column; this indirectly determines cell access to fundamental resources such as light and nutrients, and favors diatom escape from predators. At the same time, light guides phototroph movements in the water column by affecting cell density (e.g., by modulating Si deposition in diatoms, vacuole volume, and/or solution). We investigated how the tremendous diversity in morphology and silicification that characterizes the frustule and the crucial role of light in diatom spatial distribution govern diatom sinking capacity. To test their integrative effects, we acclimated four diatoms distinguished by frustule traits (Chaetoceros muelleri, Conticribra weissflogii, Phaeodactylum tricornutum, and Cylindrotheca fusiformis) to different light conditions and evaluated their physiological performance in terms of growth, elemental composition, morphological changes, and their in vivo sinking capacity. What emerged from this study was that silicification, more than other morphological characteristics, controls species vertical movements, while a higher energy availability enhances cell floating independently from the silica content.
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Kholssi R, Lougraimzi H, Moreno-Garrido I. Effects of global environmental change on microalgal photosynthesis, growth and their distribution. MARINE ENVIRONMENTAL RESEARCH 2023; 184:105877. [PMID: 36640723 DOI: 10.1016/j.marenvres.2023.105877] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 01/06/2023] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
Global climate change (GCC) constitutes a complex challenge posing a serious threat to biodiversity and ecosystems in the next decades. There are several recent studies dealing with the potential effect of increased temperature, decrease of pH or shifts in salinity, as well as cascading events of GCC and their impact on human-environment systems. Microalgae as primary producers are a sensitive compartment of the marine ecosystems to all those changes. However, the potential consequences of these changes for marine microalgae have received relatively little attention and they are still not well understood. Thus, there is an urgent need to explore and understand the effects generated by multiple climatic changes on marine microalgae growth and biodiversity. Therefore, this review aimed to compare and contrast mechanisms that marine microalgae exhibit to directly respond to harsh conditions associated with GCC and the potential consequences of those changes in marine microalgal populations. Literature shows that microalgae responses to environmental stressors such as temperature were affected differently. A stress caused by salinity might slow down cell division, reduces size, ceases motility, and triggers palmelloid formation in microalgae community, but some of these changes are strongly species-specific. UV irradiance can potentially lead to an oxidative stress in microalgae, promoting the production of reactive oxygen species (ROS) or induce direct physical damage on microalgae, then inhibiting the growth of microalgae. Moreover, pH could impact many groups of microalgae being more tolerant of certain pH shifts, while others were sensitive to changes of just small units (such as coccolithophorids) and subsequently affect the species at a higher trophic level, but also total vertical carbon transport in oceans. Overall, this review highlights the importance of examining effects of multiple stressors, considering multiple responses to understand the complexity behind stressor interactions.
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Affiliation(s)
- Rajaa Kholssi
- Composting Research Group, Faculty of Sciences, University of Burgos, Burgos, Spain; Ecology and Coastal Management, Institute of Marine Sciences of Andalusia (ICMAN-CSIC), Campus Río San Pedro, 11510, Puerto Real, Cádiz, Spain.
| | - Hanane Lougraimzi
- Laboratory of Plant, Animal and Agro-Industry Productions, Faculty of Sciences, Ibn Tofail University, BP: 242, 14000, Kenitra, Morocco
| | - Ignacio Moreno-Garrido
- Ecology and Coastal Management, Institute of Marine Sciences of Andalusia (ICMAN-CSIC), Campus Río San Pedro, 11510, Puerto Real, Cádiz, Spain
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Wang R, Meng L, Hu S, Gao P, Wang C, Chen J, Wang Y, Liu C, Song Y, Ding N. Acidification of seawater attenuates the allelopathic effects of Ulva pertusa on Karenia mikimotoi. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:5973-5982. [PMID: 35986112 DOI: 10.1007/s11356-022-22607-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
Acidification of seawater resulting from absorption of excessive carbon dioxide from the atmosphere is posing a serious threat to marine ecosystem. In this study, we hypothesized that acidified seawater attenuates allelopathic effects of macroalgae on red tide algae because the increase of dissolved carbon dioxide benefits algal growth, and investigated the allelopathic effects of Ulva pertusa on Karenia mikimotoi in response to seawater acidification by determining cell density, photosynthetic pigment content, chlorophyll fluorescence parameters, and chloroplast structure of K. mikimotoi under U. pertusa stress in original (pH=8.2) and acidified (pH=7.8) seawater. U. pertusa inhibited the growth of K. mikimotoi in the original and acidizing seawater, and the inhibition rate was positively correlated with treatment time and concentration of U. pertusa. However, acidizing condition significantly weakened the inhibition degree of U. pertusa on K. mikimotoi (P < 0.05), with the inhibition rates decreased from 51.85 to 43.16% at 10 gFW/L U. pertusa for 96 h. U. pertusa reduced contents of chlorophyll a, chlorophyll c, and carotenoid, maximum photochemical quantum yield (Fv/Fm), actual quantum yield, maximum relative electron transfer efficiency (rETRmax) of PSII, real-time fluorescence value (F), and maximum fluorescence value (Fm') of PSII of K. mikimotoi under original and acidified conditions. And, the inhibition degree of U. pertusa under acidizing condition was significantly lower than that of original seawater group. Furthermore, the damage degree of chloroplast structure of K. mikimotoi under U. pertusa stress was more serious under original seawater condition. These results indicate that acidification of seawater attenuates the allelopathic effects of U. pertusa on K. mikimotoi.
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Affiliation(s)
- Renjun Wang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, People's Republic of China.
| | - Lingna Meng
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, People's Republic of China
| | - Shunxin Hu
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, People's Republic of China
| | - Peike Gao
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, People's Republic of China
| | - Chao Wang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, People's Republic of China
| | - Junfeng Chen
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, People's Republic of China
| | - Ying Wang
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, People's Republic of China
| | - Chunchen Liu
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, People's Republic of China
| | - Yuhao Song
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, People's Republic of China
| | - Ning Ding
- College of Life Sciences, Qufu Normal University, Qufu, Shandong, 273165, People's Republic of China
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7
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Wang ZF, Jia LP, Fang LC, Wang ZH, Liu FJ, Li SX, Huang XG. Thalassiosira weissflogii grown in various Zn levels shows different ecophysiological responses to seawater acidification. MARINE POLLUTION BULLETIN 2022; 185:114327. [PMID: 36356339 DOI: 10.1016/j.marpolbul.2022.114327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 10/25/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
The presence of zinc (Zn), a vital element for algal physiological functions, coupled with the silicification of diatoms implies that it plays an integral role in the carbon and silicon cycles of the sea. In this study, we examined the effects of different pCO2 and Zn levels on growth rate, elemental compositions and silicification by Thalassiosira weissflogii. The results showed that under normal pCO2 (400 μatm), cultures of T. weissflogii were depressed for growth rate and silica incorporation rate, but encouraged for cellular silicon content, Si/C, Si/N, and sinking rate when Zn deficient (0.3 pmol L-1). However, cellular silicon and sinking rate of Zn-deficient and Zn-replete (25 pmol L-1) T. weissflogii were decreased and increased at higher pCO2 (800 μatm), respectively. Thus, acidification may affect diatoms significantly differently depending on the Zn levels of the ocean and then alter the biochemical cycling of carbon and silica.
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Affiliation(s)
- Zhao-Fei Wang
- Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 36300, China
| | - Li-Ping Jia
- Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 36300, China; Fujian Province Key of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China
| | - Ling-Chuan Fang
- Status Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China
| | - Zhen-Hong Wang
- Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 36300, China; Fujian Province Key of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China
| | - Feng-Jiao Liu
- Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 36300, China; Fujian Province Key of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China
| | - Shun-Xing Li
- Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 36300, China; Fujian Province Key of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China
| | - Xu-Guang Huang
- Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou 36300, China; Fujian Province Key of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China.
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8
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Zepernick BN, Niknejad DJ, Stark GF, Truchon AR, Martin RM, Rossignol KL, Paerl HW, Wilhelm SW. Morphological, physiological, and transcriptional responses of the freshwater diatom Fragilaria crotonensis to elevated pH conditions. Front Microbiol 2022; 13:1044464. [PMID: 36504786 PMCID: PMC9732472 DOI: 10.3389/fmicb.2022.1044464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 11/07/2022] [Indexed: 11/27/2022] Open
Abstract
Harmful algal blooms (HABs) caused by the toxin-producing cyanobacteria Microcystis spp., can increase water column pH. While the effect(s) of these basified conditions on the bloom formers are a high research priority, how these pH shifts affect other biota remains understudied. Recently, it was shown these high pH levels decrease growth and Si deposition rates in the freshwater diatom Fragilaria crotonensis and natural Lake Erie (Canada-US) diatom populations. However, the physiological mechanisms and transcriptional responses of diatoms associated with these observations remain to be documented. Here, we examined F. crotonensis with a set of morphological, physiological, and transcriptomic tools to identify cellular responses to high pH. We suggest 2 potential mechanisms that may contribute to morphological and physiological pH effects observed in F. crotonensis. Moreover, we identified a significant upregulation of mobile genetic elements in the F. crotonensis genome which appear to be an extreme transcriptional response to this abiotic stress to enhance cellular evolution rates-a process we have termed "genomic roulette." We discuss the ecological and biogeochemical effects high pH conditions impose on fresh waters and suggest a means by which freshwater diatoms such as F. crotonensis may evade high pH stress to survive in a "basified" future.
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Affiliation(s)
| | - David J. Niknejad
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Gwendolyn F. Stark
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Alexander R. Truchon
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Robbie M. Martin
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Karen L. Rossignol
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC, United States
| | - Hans W. Paerl
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC, United States
| | - Steven W. Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
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Li Y, Zhang C, He X, Hu Z. Solids retention time dependent, tunable diatom hierarchical micro/nanostructures and their effect on nutrient removal. WATER RESEARCH 2022; 216:118346. [PMID: 35358880 DOI: 10.1016/j.watres.2022.118346] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/16/2022] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
The hierarchical three-dimensional (3D) micro/nanostructures of diatoms make them a promising biomaterial for fabricating nanomaterials, producing bioactive pharmaceuticals or nutraceuticals, and removing micropollutants. For diatom production in a continuous flow system, little is known how bioreactor operating parameters, especially solids retention time (SRT), affect the 3D structures of diatoms. This study demonstrated that tunable diatom micro/nanostructures could be produced by varying the SRT of membrane bioreactors (MBRs). A diatom strain (Stephanodiscus hantzschii) was cultivated in two identical MBRs with a fixed hydraulic retention time (HRT) of 24 h and staged SRTs from 5, to 10, and to 20 d. As SRTs increased from 5 to 20 d, important characteristics of diatom micro/nanostructures showed linear decreases: the diameters of foramina on the areola layer decreased from 170 ± 10 to 130 ± 12 nm, the numbers of nanopores per cribrum layer decreased from 20 ± 3 to 12 ± 2, and the specific surface areas of the diatoms decreased from 36.01 ± 1.27 to 12.67 ± 2.45 m2·g-1. However, the average diatom heights increased from 2.9 ± 0.3 to 3.9 ± 0.4 µm, while diatom cell diameter (5 µm) and nanopore size (20 nm) remained unchanged. The silicon content of diatoms also linearly increased with SRT. The decrease in diatom porosity and increase in silicon content were probably due to the reduced diatom growth rates (likely resulting in less pores) at increasing SRTs, which also facilitated silica deposition as the overall diatom population stayed longer in the MBRs. As the SRTs increased from 5 to 10, and to 20 d, the nitrate (NO3-) removal efficiency decreased from 75% to 70%, and to 60%, respectively, whereas phosphorus (P) removal efficiency increased from 74% to 80%, and to 90%, respectively. The opposite trends in efficiencies were because NO3--N was removed by cellular uptake and biomass waste whereas P was mainly removed through diatom-assisted chemical precipitation.
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Affiliation(s)
- Yan Li
- NingboTech University, Ningbo 315000, China; Department of Civil & Environmental Engineering, University of Missouri, Columbia, Missouri, 65211, USA
| | - Chiqian Zhang
- Department of Civil & Environmental Engineering, University of Missouri, Columbia, Missouri, 65211, USA
| | - Xiaoqing He
- Electron Microscopy Core Facility, University of Missouri, Columbia, Missouri, 65211, USA; Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, Missouri, 65211, USA
| | - Zhiqiang Hu
- Department of Civil & Environmental Engineering, University of Missouri, Columbia, Missouri, 65211, USA.
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Enhanced silica export in a future ocean triggers global diatom decline. Nature 2022; 605:696-700. [PMID: 35614245 PMCID: PMC9132771 DOI: 10.1038/s41586-022-04687-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 03/24/2022] [Indexed: 12/04/2022]
Abstract
Diatoms account for up to 40% of marine primary production1,2 and require silicic acid to grow and build their opal shell3. On the physiological and ecological level, diatoms are thought to be resistant to, or even benefit from, ocean acidification4–6. Yet, global-scale responses and implications for biogeochemical cycles in the future ocean remain largely unknown. Here we conducted five in situ mesocosm experiments with natural plankton communities in different biomes and find that ocean acidification increases the elemental ratio of silicon (Si) to nitrogen (N) of sinking biogenic matter by 17 ± 6 per cent under \documentclass[12pt]{minimal}
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\begin{document}$${{p}}_{{{\rm{CO}}}_{2}}$$\end{document}pCO2 conditions projected for the year 2100. This shift in Si:N seems to be caused by slower chemical dissolution of silica at decreasing seawater pH. We test this finding with global sediment trap data, which confirm a widespread influence of pH on Si:N in the oceanic water column. Earth system model simulations show that a future pH-driven decrease in silica dissolution of sinking material reduces the availability of silicic acid in the surface ocean, triggering a global decline of diatoms by 13–26 per cent due to ocean acidification by the year 2200. This outcome contrasts sharply with the conclusions of previous experimental studies, thereby illustrating how our current understanding of biological impacts of ocean change can be considerably altered at the global scale through unexpected feedback mechanisms in the Earth system. Mesocosm experiments in different biomes show that future ocean acidification will slow down the dissolution of biogenic silica, decreasing silicic acid availability in the surface ocean and triggering a global decline of diatoms as revealed by Earth system model simulations.
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Zepernick BN, Gann ER, Martin RM, Pound HL, Krausfeldt LE, Chaffin JD, Wilhelm SW. Elevated pH Conditions Associated With Microcystis spp. Blooms Decrease Viability of the Cultured Diatom Fragilaria crotonensis and Natural Diatoms in Lake Erie. Front Microbiol 2021; 12:598736. [PMID: 33717001 PMCID: PMC7943883 DOI: 10.3389/fmicb.2021.598736] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 01/20/2021] [Indexed: 11/13/2022] Open
Abstract
Cyanobacterial Harmful Algal Blooms (CyanoHABs) commonly increase water column pH to alkaline levels ≥9.2, and to as high as 11. This elevated pH has been suggested to confer a competitive advantage to cyanobacteria such as Microcystis aeruginosa. Yet, there is limited information regarding the restrictive effects bloom-induced pH levels may impose on this cyanobacterium’s competitors. Due to the pH-dependency of biosilicification processes, diatoms (which seasonally both precede and proceed Microcystis blooms in many fresh waters) may be unable to synthesize frustules at these pH levels. We assessed the effects of pH on the ecologically relevant diatom Fragilaria crotonensis in vitro, and on a Lake Erie diatom community in situ. In vitro assays revealed F. crotonensis monocultures exhibited lower growth rates and abundances when cultivated at a starting pH of 9.2 in comparison to pH 7.7. The suppressed growth trends in F. crotonensis were exacerbated when co-cultured with M. aeruginosa at pH conditions and cell densities that simulated a cyanobacteria bloom. Estimates demonstrated a significant decrease in silica (Si) deposition at alkaline pH in both in vitro F. crotonensis cultures and in situ Lake Erie diatom assemblages, after as little as 48 h of alkaline pH-exposure. These observations indicate elevated pH negatively affected growth rate and diatom silica deposition; in total providing a competitive disadvantage for diatoms. Our observations demonstrate pH likely plays a significant role in bloom succession, creating a potential to prolong summer Microcystis blooms and constrain diatom fall resurgence.
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Affiliation(s)
- Brittany N Zepernick
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Eric R Gann
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Robbie M Martin
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Helena L Pound
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Lauren E Krausfeldt
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Justin D Chaffin
- F.T. Stone Laboratory and Ohio Sea Grant, The Ohio State University, Put-in-Bay, OH, United States
| | - Steven W Wilhelm
- Department of Microbiology, The University of Tennessee, Knoxville, Knoxville, TN, United States
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12
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Griffin DM, Kennedy MA, Bhatia SR. Calcium phosphate nanocomposites via in situ mineralization in block copolymer hydrogels. POLYM ADVAN TECHNOL 2020. [DOI: 10.1002/pat.5183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- David M. Griffin
- Department of Chemical Engineering University of Massachusetts Amherst Amherst Massachusetts USA
- Department of Chemical and Petroleum Engineering University of Kansas Lawrence Kansas USA
| | | | - Surita R. Bhatia
- Department of Chemistry Stony Brook University Stony Brook New York USA
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13
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Soleimani M, Rutten L, Maddala SP, Wu H, Eren ED, Mezari B, Schreur-Piet I, Friedrich H, van Benthem RATM. Modifying the thickness, pore size, and composition of diatom frustule in Pinnularia sp. with Al 3+ ions. Sci Rep 2020; 10:19498. [PMID: 33177559 PMCID: PMC7658998 DOI: 10.1038/s41598-020-76318-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/23/2020] [Indexed: 11/09/2022] Open
Abstract
Diatoms are unicellular photosynthetic algae that produce a silica exoskeleton (frustule) which exposes a highly ordered nano to micro scale morphology. In recent years there has been a growing interest in modifying diatom frustules for technological applications. This is achieved by adding non-essential metals to the growth medium of diatoms which in turn modifies morphology, composition, and resulting properties of the frustule. Here, we investigate the frustule formation in diatom Pinnularia sp., including changes to overall morphology, silica thickness, and composition, in the presence of Al3+ ions at different concentrations. Our results show that in the presence of Al3+ the total silica uptake from the growth medium increases, although a decrease in the growth rate is observed. This leads to a higher inorganic content per diatom resulting in a decreased pore diameter and a thicker frustule as evidenced by electron microscopy. Furthermore, 27Al solid-state NMR, FIB-SEM, and EDS results confirm that Al3+ becomes incorporated into the frustule during the silicification process, thus, improving hydrolysis resistance. This approach may be extended to a broad range of elements and diatom species towards the scalable production of silica materials with tunable hierarchical morphology and chemical composition.
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Affiliation(s)
- Mohammad Soleimani
- Laboratory of Physical Chemistry, and Center for Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 5, 5612 AE, Eindhoven, The Netherlands
| | - Luco Rutten
- Laboratory of Physical Chemistry, and Center for Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 5, 5612 AE, Eindhoven, The Netherlands
| | - Sai Prakash Maddala
- Laboratory of Physical Chemistry, and Center for Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 5, 5612 AE, Eindhoven, The Netherlands
| | - Hanglong Wu
- Laboratory of Physical Chemistry, and Center for Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 5, 5612 AE, Eindhoven, The Netherlands
| | - E Deniz Eren
- Laboratory of Physical Chemistry, and Center for Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 5, 5612 AE, Eindhoven, The Netherlands
| | - Brahim Mezari
- Laboratory for Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands
| | - Ingeborg Schreur-Piet
- Laboratory of Physical Chemistry, and Center for Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 5, 5612 AE, Eindhoven, The Netherlands
| | - Heiner Friedrich
- Laboratory of Physical Chemistry, and Center for Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 5, 5612 AE, Eindhoven, The Netherlands. .,Institute for Complex Molecular Systems, Eindhoven University of Technology, Groene Loper 5, 5612 AE, Eindhoven, The Netherlands.
| | - Rolf A T M van Benthem
- Laboratory of Physical Chemistry, and Center for Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Groene Loper 5, 5612 AE, Eindhoven, The Netherlands.
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14
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Limnological Characteristics and Diatom Dominants in Lakes of Northeastern Poland. DIVERSITY 2020. [DOI: 10.3390/d12100374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Determination of the relationships between environmental factors and diatom assemblages is usually made for several hundred lakes spread over a large area. However, the analysis of several lakes located near Lake Wigry also gives interesting results. Lakes in Wigry National Park (Poland) with broad similarity of geological origin show clear limnological, physical, and chemical differences. Here, we report on an investigation into how these dissimilarities influence diatom assemblages. Hierarchical Cluster Analysis showed that the studied lakes can be divided into three groups: (1) disharmonic, (2) harmonious with greater human impact on the environment, and (3) harmonious with a more limited human impact. The harmonious lakes could be divided into two groups that are mainly in line with the contents of the chloride and sulfates ions taken as indicative of human impacts on the environment. Overall, the three groups had different dominance structures, as reference to the Dominance Index (DI) made clear (mean values being: (1) −70.54%, (2) −72%, and (3) −54.58%, Generalized Linear Models with the categorical independent variable (group) showed significant differences between groups (for 1–3, 2–3) p value < 0.05). Lakes impacted by anthropopressure and disharmonic ones had the strongest dominance structure. More broadly, DI differences between the groups are consistent with the Species Pool Hypothesis (SPH), while studied differences can be said to result from natural geological dissimilarities, as well as disparate anthropogenic impacts.
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15
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Launay H, Huang W, Maberly SC, Gontero B. Regulation of Carbon Metabolism by Environmental Conditions: A Perspective From Diatoms and Other Chromalveolates. FRONTIERS IN PLANT SCIENCE 2020; 11:1033. [PMID: 32765548 PMCID: PMC7378808 DOI: 10.3389/fpls.2020.01033] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/23/2020] [Indexed: 05/08/2023]
Abstract
Diatoms belong to a major, diverse and species-rich eukaryotic clade, the Heterokonta, within the polyphyletic chromalveolates. They evolved as a result of secondary endosymbiosis with one or more Plantae ancestors, but their precise evolutionary history is enigmatic. Nevertheless, this has conferred them with unique structural and biochemical properties that have allowed them to flourish in a wide range of different environments and cope with highly variable conditions. We review the effect of pH, light and dark, and CO2 concentration on the regulation of carbon uptake and assimilation. We discuss the regulation of the Calvin-Benson-Bassham cycle, glycolysis, lipid synthesis, and carbohydrate synthesis at the level of gene transcripts (transcriptomics), proteins (proteomics) and enzyme activity. In contrast to Viridiplantae where redox regulation of metabolic enzymes is important, it appears to be less common in diatoms, based on the current evidence, but regulation at the transcriptional level seems to be widespread. The role of post-translational modifications such as phosphorylation, glutathionylation, etc., and of protein-protein interactions, has been overlooked and should be investigated further. Diatoms and other chromalveolates are understudied compared to the Viridiplantae, especially given their ecological importance, but we believe that the ever-growing number of sequenced genomes combined with proteomics, metabolomics, enzyme measurements, and the application of novel techniques will provide a better understanding of how this important group of algae maintain their productivity under changing conditions.
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Affiliation(s)
- Hélène Launay
- BIP, Aix Marseille Univ CNRS, BIP UMR 7281, Marseille, France
| | - Wenmin Huang
- BIP, Aix Marseille Univ CNRS, BIP UMR 7281, Marseille, France
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China
| | - Stephen C. Maberly
- UK Centre for Ecology & Hydrology, Lake Ecosystems Group, Lancaster Environment Centre, Lancaster, United Kingdom
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16
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Li K, Li M, He Y, Gu X, Pang K, Ma Y, Lu D. Effects of pH and nitrogen form on Nitzschia closterium growth by linking dynamic with enzyme activity. CHEMOSPHERE 2020; 249:126154. [PMID: 32062215 DOI: 10.1016/j.chemosphere.2020.126154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 01/16/2020] [Accepted: 02/07/2020] [Indexed: 06/10/2023]
Abstract
In this study, Nitzschia closterium was incubated in seawater at different pH values (8.10, 7.71, and 7.45) and using different nitrogen forms (NO3-N and NH4-N) in the laboratory. The results showed that the growth of N. closterium was inhibited by ocean acidification, with individuals under lower pH levels showing lower growth rates and lower nitrogen uptake rates for both nitrogen forms. The Vmax/Ks ratio decreased with decreasing pH, indicating the inhibition of nitrogen uptake, whereas the ratios for NH4-N cultures were higher than those for NO3-N cultures, implying the highly competitive position of NH4-N. Acidification might induce reactive oxygen species based on the result that the maximum enzyme activities of SuperOxide Dismutase (SOD) and CATalase (CAT) increased under lower pH levels. The SOD and CAT activities for the NO3-N cultures were higher than those for NH4-N cultures at the low pH level, indicating that acidification might cause more oxidative stress for NO3-N cultures than for NH4-N cultures. Thus, ocean acidification might have a more detrimental effect on the growth of N. closterium under NO3-N conditions than NH4-N conditions, with a lower ratio (γ) of the maximum growth rate to the maximum nutrient uptake rate, and a drop in nitrate reductase activity under lower pH levels.
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Affiliation(s)
- Keqiang Li
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.
| | - Min Li
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China
| | - Yunfeng He
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China
| | - Xingyan Gu
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China
| | - Kai Pang
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China
| | - Yunpeng Ma
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qing Dao, 266100, China; Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
| | - Dongliang Lu
- Guangxi Key Laboratory of Marine Disaster in the Beibu Gulf, Beibu Gulf University, Qinzhou, 535011, China
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17
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Yee DP, Hildebrand M, Tresguerres M. Dynamic subcellular translocation of V-type H + -ATPase is essential for biomineralization of the diatom silica cell wall. THE NEW PHYTOLOGIST 2020; 225:2411-2422. [PMID: 31746463 DOI: 10.1111/nph.16329] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
Diatom cell walls, called frustules, are main sources of biogenic silica in the ocean and their intricate morphology is an inspiration for nanoengineering. Here we show dynamic aspects of frustule biosynthesis involving acidification of the silica deposition vesicle (SDV) by V-type H+ ATPase (VHA). Transgenic Thalassiosira pseudonana expressing the VHA B subunit tagged with enhanced green fluorescent protein (VHAB -eGFP) enabled subcellular protein localization in live cells. In exponentially growing cultures, VHAB -eGFP was present in various subcellular localizations including the cytoplasm, SDVs and vacuoles. We studied the role of VHA during frustule biosynthesis in synchronized cell cultures of T. pseudonana. During the making of new biosilica components, VHAB -eGFP first localized in the girdle band SDVs, and subsequently in valve SDVs. In single cell time-lapse imaging experiments, VHAB -eGFP localization in SDVs precluded accumulation of the acidotropic silica biomineralization marker PDMPO. Furthermore, pharmacological VHA inhibition prevented PDMPO accumulation in the SDV, frustule biosynthesis and cell division, as well as insertion of the silicalemma-associated protein SAP1 into the SDVs. Finally, partial inhibition of VHA activity affected the nanoscale morphology of the valve. Altogether, these results indicate that VHA is essential for frustule biosynthesis by acidifying the SDVs and regulating the insertion of other structural proteins into the SDV.
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Affiliation(s)
- Daniel P Yee
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Mark Hildebrand
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Martin Tresguerres
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
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18
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Raven JA, Gobler CJ, Hansen PJ. Dynamic CO 2 and pH levels in coastal, estuarine, and inland waters: Theoretical and observed effects on harmful algal blooms. HARMFUL ALGAE 2020; 91:101594. [PMID: 32057340 DOI: 10.1016/j.hal.2019.03.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 06/10/2023]
Abstract
Rising concentrations of atmospheric CO2 results in higher equilibrium concentrations of dissolved CO2 in natural waters, with corresponding increases in hydrogen ion and bicarbonate concentrations and decreases in hydroxyl ion and carbonate concentrations. Superimposed on these climate change effects is the dynamic nature of carbon cycling in coastal zones, which can lead to seasonal and diel changes in pH and CO2 concentrations that can exceed changes expected for open ocean ecosystems by the end of the century. Among harmful algae, i.e. some species and/or strains of Cyanobacteria, Dinophyceae, Prymnesiophyceae, Bacillariophyceae, and Ulvophyceae, the occurrence of a CO2 concentrating mechanisms (CCMs) is the most frequent mechanism of inorganic carbon acquisition in natural waters in equilibrium with the present atmosphere (400 μmol CO2 mol-1 total gas), with varying phenotypic modification of the CCM. No data on CCMs are available for Raphidophyceae or the brown tide Pelagophyceae. Several HAB species and/or strains respond to increased CO2 concentrations with increases in growth rate and/or cellular toxin content, however, others are unaffected. Beyond the effects of altered C concentrations and speciation on HABs, changes in pH in natural waters are likely to have profound effects on algal physiology. This review outlines the implications of changes in inorganic cycling for HABs in coastal zones, and reviews the knowns and unknowns with regard to how HABs can be expected to ocean acidification. We further point to the large regions of uncertainty with regard to this evolving field.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK; Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, 2007, Australia; School of Biological Science, University of Western Australia, Crawley, WA, 6009, Australia.
| | - Christopher J Gobler
- School of Marine and Atmospheric Sciences, Stony Brook University, Southampton NY, 11968, USA.
| | - Per Juel Hansen
- University of Copenhagen, Marine Biological Section, Strandpromenaden 5, DK 3000 Helsingør, Denmark
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19
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Seto DS, Karp-Boss L, Wells ML. Effects of increasing temperature and acidification on the growth and competitive success of Alexandrium catenella from the Gulf of Maine. HARMFUL ALGAE 2019; 89:101670. [PMID: 31672235 DOI: 10.1016/j.hal.2019.101670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/30/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Climate driven increases in ocean temperature and pCO2 have the potential to alter the growth and prevalence of future Harmful Algal Blooms (HABs), but systematic studies on how climate drivers influence toxic algal species relative to non-toxic phytoplankton are lacking. In particular, little is known about how future climate scenarios will affect the growth of the toxic dinoflagellate Alexandrium catenella, which is responsible for the paralytic shellfish poisoning (PSP) events that threaten the health and economy of coastal communities in the Gulf of Maine and elsewhere. The growth responses of A. catenella and two other naturally co-occurring dinoflagellates in the Gulf of Maine-Scrippsiella sp., and Amphidinium carterae-were studied in mono and mixed species cultures. Experimental treatments tested the effects of elevated temperature (20 °C), lower pH (7.8), and the combination of elevated temperature and lower pH on growth rates relative to those in near-current conditions (15 °C; pH 8.1). Growth rates of A. catenella decreased under elevated temperature and lower pH conditions, a response that was largely attributable to the effect of temperature. In contrast, growth rates of Scrippsiella sp. and A. carterae increased under elevated temperature and lower pH conditions, with temperature also being the primary driver of the response. These trends did not change substantially when these species were grown in mixed cultures (A. catenella + Scrippsiella sp., and A. catenella + A. carterae), indicating that allelopathic or competitive interactions did not affect the experimental outcome under the conditions tested. These findings suggest that A. catenella blooms may become less prevalent in the southern regions of the Gulf of Maine, but potentially more prevalent in the northeastern regions of the Gulf of Maine with continued climate change.
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Affiliation(s)
- Drajad S Seto
- School of Marine Science, University of Maine, Orono, ME, 04469, USA.
| | - Lee Karp-Boss
- School of Marine Science, University of Maine, Orono, ME, 04469, USA.
| | - Mark L Wells
- School of Marine Science, University of Maine, Orono, ME, 04469, USA; State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, 36 Baochubei Road, Hangzhou, 310012, China.
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20
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Li W, Ding J, Li F, Wang T, Yang Y, Li Y, Campbell DA, Gao K. Functional responses of smaller and larger diatoms to gradual CO 2 rise. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 680:79-90. [PMID: 31102831 DOI: 10.1016/j.scitotenv.2019.05.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/27/2019] [Accepted: 05/03/2019] [Indexed: 06/09/2023]
Abstract
Diatoms and other phytoplankton groups are exposed to abrupt changes in pCO2, in waters in upwelling areas, near CO2 seeps, or during their blooms; or to more gradual pCO2 rise through anthropogenic CO2 emissions. Gradual CO2 rises have, however, rarely been included in ocean acidification (OA) studies. We therefore compared how small (Thalassiosira pseudonana) and larger (Thalassiosira weissflogii) diatom cell isolates respond to gradual pCO2 rises from 180 to 1000 μatm in steps of ~40 μatm with 5-10 generations at each step, and whether their responses to gradual pCO2 rise differ when compared to an abrupt pCO2 rise imposed from ambient 400 directly to 1000 μatm. Cell volume increased in T. pseudonana but decreased in T. weissflogii with an increase from low to moderate CO2 levels, and then remained steady under yet higher CO2 levels. Growth rates were stimulated, but Chl a, particulate organic carbon (POC) and cellular biogenic silica (BSi) decreased from low to moderate CO2 levels, and then remained steady with further CO2 rise in both species. Decreased saturation light intensity (Ik) and light use efficiency (α) with CO2 rise in T. pseudonana indicate that the smaller diatom becomes more susceptible to photoinhibition. Decreased BSi/POC (Si/C) in T. weissflogii indicates the biogeochemical cycles of both silicon and carbon may be more affected by elevated pCO2 in the larger diatom. The different CO2 modulation methods resulted in different responses of some key physiological parameters. Increasing pCO2 from 180 to 400 μatm decreased cellular POC and BSi contents, implying that ocean acidification to date has already altered diatom contributions to carbon and silicon biogeochemical processes.
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Affiliation(s)
- Wei Li
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; College of Life and Environmental Sciences, Huangshan University, Huangshan 245041, China
| | - Jiancheng Ding
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Futian Li
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Tifeng Wang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Yuling Yang
- College of Life and Environmental Sciences, Huangshan University, Huangshan 245041, China
| | - Yahe Li
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; School of Marine Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
| | - Douglas A Campbell
- Biology Department, Mount Allison University, Sackville, NB E4L 1G7, Canada
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China.
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21
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Ewe D, Tachibana M, Kikutani S, Gruber A, Río Bártulos C, Konert G, Kaplan A, Matsuda Y, Kroth PG. The intracellular distribution of inorganic carbon fixing enzymes does not support the presence of a C4 pathway in the diatom Phaeodactylum tricornutum. PHOTOSYNTHESIS RESEARCH 2018; 137:263-280. [PMID: 29572588 DOI: 10.1007/s11120-018-0500-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/18/2018] [Indexed: 05/20/2023]
Abstract
Diatoms are unicellular algae and important primary producers. The process of carbon fixation in diatoms is very efficient even though the availability of dissolved CO2 in sea water is very low. The operation of a carbon concentrating mechanism (CCM) also makes the more abundant bicarbonate accessible for photosynthetic carbon fixation. Diatoms possess carbonic anhydrases as well as metabolic enzymes potentially involved in C4 pathways; however, the question as to whether a C4 pathway plays a general role in diatoms is not yet solved. While genome analyses indicate that the diatom Phaeodactylum tricornutum possesses all the enzymes required to operate a C4 pathway, silencing of the pyruvate orthophosphate dikinase (PPDK) in a genetically transformed cell line does not lead to reduced photosynthetic carbon fixation. In this study, we have determined the intracellular location of all enzymes potentially involved in C4-like carbon fixing pathways in P. tricornutum by expression of the respective proteins fused to green fluorescent protein (GFP), followed by fluorescence microscopy. Furthermore, we compared the results to known pathways and locations of enzymes in higher plants performing C3 or C4 photosynthesis. This approach revealed that the intracellular distribution of the investigated enzymes is quite different from the one observed in higher plants. In particular, the apparent lack of a plastidic decarboxylase in P. tricornutum indicates that this diatom does not perform a C4-like CCM.
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Affiliation(s)
- Daniela Ewe
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany.
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Třeboň, Czech Republic.
| | - Masaaki Tachibana
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, 669-1337, Japan
- Lion Corporation Pharmaceutical Laboratories No.1, Odawara, Kanagawa, 256-0811, Japan
| | - Sae Kikutani
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, 669-1337, Japan
- Tech Manage Corp., Tokyo, 160-0023, Japan
| | - Ansgar Gruber
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Czech Republic
| | | | - Grzegorz Konert
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Třeboň, Czech Republic
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus-Givat Ram, Hebrew University of Jerusalem, 91904, Jerusalem, Israel
| | - Yusuke Matsuda
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo, 669-1337, Japan
| | - Peter G Kroth
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany
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Su Y, Lundholm N, Ellegaard M. Effects of abiotic factors on the nanostructure of diatom frustules—ranges and variability. Appl Microbiol Biotechnol 2018; 102:5889-5899. [DOI: 10.1007/s00253-018-9087-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/08/2018] [Accepted: 05/10/2018] [Indexed: 11/28/2022]
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23
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Grachev MA, Bedoshvili YD, Gerasimov EY, Zaikovskii VI, Gneusheva KV, Likhoshway YV. Silica-containing inclusions in the cytoplasm of diatom Synedra acus. DOKL BIOCHEM BIOPHYS 2017; 472:44-48. [DOI: 10.1134/s1607672917010124] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Indexed: 11/23/2022]
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24
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Ding T, Zhang J, Ni W, Li J. Combined toxicity of arsenite and dimethylarsenic acid on the freshwater diatom Nitzschia palea. ECOTOXICOLOGY (LONDON, ENGLAND) 2017; 26:202-210. [PMID: 28044217 DOI: 10.1007/s10646-016-1755-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/16/2016] [Indexed: 06/06/2023]
Abstract
The toxicity and bioavailability of single arsenic species have been widely investigated, however, the biological effects of mixed arsenic species co-existing in natural waters still remain unknown. The objective of this work was to discern the adverse effects of combined arsenite (As(III)) and dimethylarsenic acid (DMA) on diatom Nitzschia palea. The combined ecotoxicity of As(III) and DMA on N. palea was observed to be time-dependent and showed dose-effect relation. The toxicity of DMA and As(III) mixture was higher than individual DMA or As(III) when the As(III) concentration was in the range of 0.085-0.316 mg L-1. As the As(III) concentration increased from 0.487 to 0.858 mg L-1, the antagonistic effect was found, which could be due to the higher thiols contents in the thiol-containing proteins (e.g., frustulins, silaffins and other glycoproteins). The content of malondialdehyde (MDA) in the treatment of mixed arsenic species was found to be at the same level compared to the As-free control after 72 h of exposure, indicating that the co-toxicity of As(III) and DMA on diatom frustules was not significant. Furthermore, the increase of frustule formation rate in the mixture of EC50 As(III)-EC10 DMA at 72 h exposure time indicated that the damaged diatom cell walls was likely repaired gradually. The results from this study suggested that the effects of co-existed arsenic species were concentration-specific and should be considered in the risk assessment of arsenic and development of water quality criteria for the protection of aquatic ecosystems.
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Affiliation(s)
- Tengda Ding
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China.
- Environmental Science Institute, Zhejiang University, Hangzhou, 310058, China.
| | - Jianying Zhang
- Environmental Science Institute, Zhejiang University, Hangzhou, 310058, China
| | - Wanmin Ni
- Department of Chemistry, College of Science and Technology, Zhejiang International Studies University, Hangzhou, 310012, China
| | - Juying Li
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
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25
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Machado M, Bromke M, Domingues Júnior AP, Marçal Vieira Vaz MG, Rosa RM, Vinson CC, Sabir JS, Rocha DI, Martins MA, Araújo WL, Willmitzer L, Szymanski J, Nunes-Nesi A. Comprehensive metabolic reprograming in freshwater Nitzschia palea strains undergoing nitrogen starvation is likely associated with its ecological origin. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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26
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Bussard A, Corre E, Hubas C, Duvernois-Berthet E, Le Corguillé G, Jourdren L, Coulpier F, Claquin P, Lopez PJ. Physiological adjustments and transcriptome reprogramming are involved in the acclimation to salinity gradients in diatoms. Environ Microbiol 2016; 19:909-925. [DOI: 10.1111/1462-2920.13398] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Adrien Bussard
- UMR Biologie des Organismes et des Ecosystèmes Aquatiques, CNRS 7208-MNHN-UPMC-IRD 207-UCN-UA; 43 rue Cuvier Paris 75005 France
| | - Erwan Corre
- CNRS, UPMC, FR2424, ABiMS, Station Biologique; Roscoff 29680 France
| | - Cédric Hubas
- UMR Biologie des Organismes et des Ecosystèmes Aquatiques, CNRS 7208-MNHN-UPMC-IRD 207-UCN-UA; 43 rue Cuvier Paris 75005 France
| | | | | | - Laurent Jourdren
- Ecole Normale Supérieure, PSL Research University, CNRS, Inserm, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Plateforme Génomique; Paris 75005 France
| | - Fanny Coulpier
- Ecole Normale Supérieure, PSL Research University, CNRS, Inserm, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Plateforme Génomique; Paris 75005 France
| | - Pascal Claquin
- UMR Biologie des Organismes et des Ecosystèmes Aquatiques, CNRS 7208-MNHN-UPMC-IRD 207-UCN-UA, Esplanade de la paix; Caen 14032 France
| | - Pascal Jean Lopez
- UMR Biologie des Organismes et des Ecosystèmes Aquatiques, CNRS 7208-MNHN-UPMC-IRD 207-UCN-UA; 43 rue Cuvier Paris 75005 France
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Marine Microphytobenthic Assemblage Shift along a Natural Shallow-Water CO2 Gradient Subjected to Multiple Environmental Stressors. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2015. [DOI: 10.3390/jmse3041425] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Roleda MY, Cornwall CE, Feng Y, McGraw CM, Smith AM, Hurd CL. Effect of Ocean Acidification and pH Fluctuations on the Growth and Development of Coralline Algal Recruits, and an Associated Benthic Algal Assemblage. PLoS One 2015; 10:e0140394. [PMID: 26469945 PMCID: PMC4607452 DOI: 10.1371/journal.pone.0140394] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/24/2015] [Indexed: 11/19/2022] Open
Abstract
Coralline algae are susceptible to the changes in the seawater carbonate system associated with ocean acidification (OA). However, the coastal environments in which corallines grow are subject to large daily pH fluctuations which may affect their responses to OA. Here, we followed the growth and development of the juvenile coralline alga Arthrocardia corymbosa, which had recruited into experimental conditions during a prior experiment, using a novel OA laboratory culture system to simulate the pH fluctuations observed within a kelp forest. Microscopic life history stages are considered more susceptible to environmental stress than adult stages; we compared the responses of newly recruited A. corymbosa to static and fluctuating seawater pH with those of their field-collected parents. Recruits were cultivated for 16 weeks under static pH 8.05 and 7.65, representing ambient and 4× preindustrial pCO2 concentrations, respectively, and two fluctuating pH treatments of daily [Formula: see text] (daytime pH = 8.45, night-time pH = 7.65) and daily [Formula: see text] (daytime pH = 8.05, night-time pH = 7.25). Positive growth rates of new recruits were recorded in all treatments, and were highest under static pH 8.05 and lowest under fluctuating pH 7.65. This pattern was similar to the adults' response, except that adults had zero growth under fluctuating pH 7.65. The % dry weight of MgCO3 in calcite of the juveniles was reduced from 10% at pH 8.05 to 8% at pH 7.65, but there was no effect of pH fluctuation. A wide range of fleshy macroalgae and at least 6 species of benthic diatoms recruited across all experimental treatments, from cryptic spores associated with the adult A. corymbosa. There was no effect of experimental treatment on the growth of the benthic diatoms. On the community level, pH-sensitive species may survive lower pH in the presence of diatoms and fleshy macroalgae, whose high metabolic activity may raise the pH of the local microhabitat.
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Affiliation(s)
| | | | - Yuanyuan Feng
- Department of Botany, University of Otago, Dunedin, New Zealand
| | | | - Abigail M. Smith
- Department of Marine Science, University of Otago, Dunedin, New Zealand
| | - Catriona L. Hurd
- Department of Botany, University of Otago, Dunedin, New Zealand
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
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29
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Tait K, Beesley A, Findlay HS, McNeill CL, Widdicombe S. Elevated CO2induces a bloom of microphytobenthos within a shell gravel mesocosm. FEMS Microbiol Ecol 2015. [DOI: 10.1093/femsec/fiv092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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30
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Hopkinson BM. A chloroplast pump model for the CO2 concentrating mechanism in the diatom Phaeodactylum tricornutum. PHOTOSYNTHESIS RESEARCH 2014; 121:223-33. [PMID: 24292858 DOI: 10.1007/s11120-013-9954-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 11/18/2013] [Indexed: 05/19/2023]
Abstract
Prior analysis of inorganic carbon (Ci) fluxes in the diatom Phaeodactylum tricornutum has indicated that transport of Ci into the chloroplast from the cytoplasm is the major Ci flux in the cell and the primary driving force for the CO2 concentrating mechanism (CCM). This flux drives the accumulation of Ci in the chloroplast stroma and generates a CO2 deficit in the cytoplasm, inducing CO2 influx into the cell. Here, the "chloroplast pump" model of the CCM in P. tricornutum is formalized and its consistency with data on CO2 and HCO3 (-) uptake rates, carbonic anhydrase (CA) activity, intracellular Ci concentration, intracellular pH, and RubisCO characteristics is assessed. The chloroplast pump model can account for the major features of the data. Analysis of photosynthetic and Ci uptake rates as a function of external Ci concentration shows that the model has the most difficulty obtaining sufficiently low cytoplasmic CO2 concentrations to support observed CO2 uptake rates at low external Ci concentrations and achieving high rates of photosynthesis. There are multiple ways in which model parameters can be varied, within a plausible range, to match measured rates of photosynthesis and CO2 uptake. To increase CO2 uptake rates, CA activity can be increased, kinetic characteristics of the putative chloroplast pump can be enhanced to increase HCO3 (-) export, or the cytoplasmic pH can be raised. To increase the photosynthetic rate, the permeability of the pyrenoid to CO2 can be reduced or RubisCO content can be increased.
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Affiliation(s)
- Brian M Hopkinson
- Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA,
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Clark DR, Flynn KJ, Fabian H. Variation in elemental stoichiometry of the marine diatom Thalassiosira weissflogii (Bacillariophyceae) in response to combined nutrient stress and changes in carbonate chemistry. JOURNAL OF PHYCOLOGY 2014; 50:640-651. [PMID: 26988448 DOI: 10.1111/jpy.12208] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 05/11/2014] [Indexed: 06/05/2023]
Abstract
The combined consequences of the multi-stressors of pH and nutrient availability upon the growth of a marine diatom were investigated. Thalassiosira weissflogii was grown in N- or P-limited batch culture in sealed systems, with pH commencing at 8.2 ("extant" conditions) or 7.6 ("ocean acidification" [OA] conditions), and then pH was allowed to either drift with growth, or was held fixed. Results indicated that within the pH range tested, the stability of environmental pH rather than its value (i.e., OA vs. extant) fundamentally influenced biomass accumul-ation and C:N:P stoichiometry. Despite large changes in total alkalinity in the fixed pH systems, final biomass production was consistently greater in these systems than that in drifting pH systems. In drift systems, pH increased to exceed pH 9.5, a level of alkalinity that was inhibitory to growth. No statis-tically significant differences between pH treatments were measured for N:C, P:C or N:P ratios during nutrient-replete growth, although the diatom expre-ssed greater plasticity in P:C and N:P ratios than in N:C during this growth phase. During nutrient-deplete conditions, the capacity for uncoupled carbon fixa-tion at fixed pH was considerably greater than that measured in drift pH systems, leading to strong contrasts in C:N:P stoichiometry between these treatments. Whether environmental pH was stable or drifted directly influenced the extent of physiological stress. In contrast, few distinctions could be drawn between "extant" versus "OA" conditions for cell physiology.
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Affiliation(s)
- Darren R Clark
- Plymouth Marine Laboratory, Prospect Place, Plymouth, PL1 3DH, UK
| | - Kevin J Flynn
- Centre for Sustainable Aquatic Research (CSAR), Swansea University, Wallace Building, Swansea, SA2 8PP, UK
| | - Heiner Fabian
- Centre for Sustainable Aquatic Research (CSAR), Swansea University, Wallace Building, Swansea, SA2 8PP, UK
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32
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Gao K, Campbell DA. Photophysiological responses of marine diatoms to elevated CO 2 and decreased pH: a review. FUNCTIONAL PLANT BIOLOGY : FPB 2014; 41:449-459. [PMID: 32481004 DOI: 10.1071/fp13247] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 12/24/2013] [Indexed: 05/19/2023]
Abstract
Diatoms dominate nearly half of current oceanic productivity, so their responses to ocean acidification are of general concern regarding future oceanic carbon sequestration. Community, mesocosm and laboratory studies show a range of diatom growth and photophysiological responses to increasing pCO2. Nearly 20 studies on effects of elevated pCO2 on diatoms have shown stimulations, no effects or inhibitions of growth rates. These differential responses could result from differences in experimental setups, cell densities, levels of light and temperature, but also from taxon-specific physiology. Generally, ocean acidification treatments of lowered pH with elevated CO2 stimulate diatom growth under low to moderate levels of light, but lead to growth inhibition when combined with excess light. Additionally, diatom cell sizes and their co-varying metabolic rates can influence responses to increasing pCO2 and decreasing pH, although cell size effects are confounded with taxonomic specificities in cell structures and metabolism. Here we summarise known diatom growth and photophysiological responses to increasing pCO2 and decreasing pH, and discuss some reasons for the diverse responses observed across studies.
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Affiliation(s)
- Kunshan Gao
- State Key Laboratory of Marine Environmental Science, Xiamen University, 361005 Xiamen, China
| | - Douglas A Campbell
- Department of Biology, Mount Allison University, Sackville, NB E4L 1G7, Canada
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Gibbin EM, Putnam HM, Davy SK, Gates RD. Intracellular pH and its response to CO2-driven seawater acidification in symbiotic versus non-symbiotic coral cells. J Exp Biol 2014; 217:1963-9. [DOI: 10.1242/jeb.099549] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Regulating intracellular pH (pHi) is critical for optimising the metabolic activity of corals, yet mechanisms involved in pH regulation and the buffering capacity within coral cells are not well understood. Our study investigated how the presence of symbiotic dinoflagellates affects the response of pHi to pCO2-driven seawater acidification in cells isolated from Pocillopora damicornis. Using the fluorescent dye BCECF-AM, in conjunction with confocal microscopy, we simultaneously characterised the response of pHi in host coral cells and their dinoflagellate symbionts, in symbiotic and non-symbiotic states under saturating light, with and without the photosynthetic inhibitor DCMU. Each treatment was run under control (pH 7.8) and CO2 acidified seawater conditions (decreasing pH from 7.8 - 6.8). After two hours of CO2 addition, by which time the external pH (pHe) had declined to 6.8, the dinoflagellate symbionts had increased their pHi by 0.5 pH units above control levels. In contrast, in both symbiotic and non-symbiotic host coral cells, 15 min of CO2 addition (0.2 pH unit drop in pHe) led to cytoplasmic acidosis equivalent to 0.4 pH units. Despite further seawater acidification over the duration of the experiment, the pHi of non-symbiotic coral cells did not change, though in host cells containing a symbiont cell the pHi recovered to control levels. This recovery was negated when cells were incubated with DCMU. Our results reveal that photosynthetic activity of the endosymbiont is tightly coupled with the ability of the host cell to recover from cellular acidosis after exposure to high CO2 / low pH.
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