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Liu Y, Xu X, Fan W, Wang G, Deng X, Rong G, Wang H. Mechanistic characterization of dissolved inorganic phosphorus in water during the red tide. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 214:108948. [PMID: 39043057 DOI: 10.1016/j.plaphy.2024.108948] [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: 04/11/2024] [Revised: 06/23/2024] [Accepted: 07/16/2024] [Indexed: 07/25/2024]
Abstract
The eutrophication of water, such as excessive nitrogen and phosphorus, are closely associated with the outbreak of red tide. However, the response of dissolved inorganic phosphorus (DIP) to red tide remained unclear in water. In this study, three species of diatoms capable of causing red tides were cultured in simulated seawater with different concentrations of DIP. The changes of biomass, chlorophyll a concentration and the carbon stable isotope composition of microalgae, the DIP concentration and pH of the culture medium were compared among the experimental groups. In addition, correlation verification was used to test the correlation between the change of DIP concentration and other indicators. The results showed that in the experimental period, the DIP concentration of each experimental group decreased significantly first, and the concentration dropped to less than 40% of the initial level. After that, the pH of the medium, the biomass, chlorophyll a concentration and carbon stable isotope composition of the microalgae showed varying degrees of increase, and then stabilized or decreased. These also marked the outbreak of red tide. Moreover, the correlation test showed that there was a correlation between them and the change of DIP concentration. Therefore, by exploring the relationship between the change of DIP concentration in water and the occurrence of red tide, this study provides a possible direction for the current prediction of red tide, and provides a basis for further investigation of the occurrence mechanism of red tide.
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Affiliation(s)
- Yu Liu
- College of Environmental Science and Engineering, Dalian Maritime University, No. 1 Linghai Road, Dalian, 116026, PR China.
| | - Xiaohan Xu
- College of Environmental Science and Engineering, Dalian Maritime University, No. 1 Linghai Road, Dalian, 116026, PR China
| | - Weijia Fan
- College of Environmental Science and Engineering, Dalian Maritime University, No. 1 Linghai Road, Dalian, 116026, PR China
| | - Guoguang Wang
- College of Environmental Science and Engineering, Dalian Maritime University, No. 1 Linghai Road, Dalian, 116026, PR China
| | - Xiaoshuang Deng
- College of Environmental Science and Engineering, Dalian Maritime University, No. 1 Linghai Road, Dalian, 116026, PR China
| | - Guangzhi Rong
- College of Environmental Science and Engineering, Dalian Maritime University, No. 1 Linghai Road, Dalian, 116026, PR China
| | - Haixia Wang
- Navigation College, Dalian Maritime University, No.1 Linghai Road, Dalian, 116026, PR China
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2
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Brown M, Ambrosone M, Turner KJ, Humphries GE, Tzortziou M, Anglès S, Panzeca C, Greenfield DI. Phytoplankton assemblage responses to nitrogen following COVID-19 stay-in-place orders in western Long Island Sound (New York/Connecticut). MARINE ENVIRONMENTAL RESEARCH 2024; 196:106371. [PMID: 38309244 DOI: 10.1016/j.marenvres.2024.106371] [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: 09/01/2023] [Revised: 12/05/2023] [Accepted: 01/17/2024] [Indexed: 02/05/2024]
Abstract
This study evaluated water quality, nitrogen (N), and phytoplankton assemblage linkages along the western Long Island Sound (USA) shoreline (Nov. 2020-Dec. 2021) following COVID-19 stay-in-place (SIP) orders through monthly surveys and N-addition bioassays. Ammonia-N (AmN; NH3+NH4+) negatively correlated with total chlorophyll-a (chl-a) at all sites; this was significant at Alley Creek, adjacent to urban wastewater inputs, and at Calf Pasture, by the Norwalk River (Spearman rank correlation, p < 0.01 and 0.02). Diatoms were abundant throughout the study, though dinoflagellates (Heterocapsa, Prorocentrum), euglenoids/cryptophytes, and both nano- and picoplankton biomass increased during summer. In field and experimental assessments, high nitrite + nitrate (N + N) and low AmN increased diatom abundances while AmN was positively linked to cryptophyte concentrations. Likely N + N decreases with presumably minimal changes in AmN and organic N during COVID-19 SIP resulted in phytoplankton assemblage shifts (decreased diatoms, increased euglenoids/cryptophytes), highlighting the ecological impacts of N-form delivered by wastewater to urban estuaries.
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Affiliation(s)
- Maximillian Brown
- School of Earth and Environmental Sciences, Queens College, City University of New York, Flushing, NY, 11367, USA; Advanced Science Research Center at the Graduate Center, City University of New York, New York, NY, 10031, USA
| | - Mariapaola Ambrosone
- Advanced Science Research Center at the Graduate Center, City University of New York, New York, NY, 10031, USA
| | - Kyle J Turner
- Earth and Atmospheric Science, Center for Discovery and Innovation, The City College of New York, City University of New York, New York, NY, 10031, USA
| | - Georgie E Humphries
- School of Earth and Environmental Sciences, Queens College, City University of New York, Flushing, NY, 11367, USA; Advanced Science Research Center at the Graduate Center, City University of New York, New York, NY, 10031, USA
| | - Maria Tzortziou
- Earth and Atmospheric Science, Center for Discovery and Innovation, The City College of New York, City University of New York, New York, NY, 10031, USA
| | - Sílvia Anglès
- Advanced Science Research Center at the Graduate Center, City University of New York, New York, NY, 10031, USA
| | - Caterina Panzeca
- State University of New York Maritime College, Bronx, NY, 10465, USA
| | - Dianne I Greenfield
- School of Earth and Environmental Sciences, Queens College, City University of New York, Flushing, NY, 11367, USA; Advanced Science Research Center at the Graduate Center, City University of New York, New York, NY, 10031, USA.
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3
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Dai S, Zhou Y, Li N, Mao XZ. Why do red tides occur frequently in some oligotrophic waters? Analysis of red tide evolution history in Mirs Bay, China and its implications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 844:157112. [PMID: 35787897 DOI: 10.1016/j.scitotenv.2022.157112] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 06/05/2022] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
The process and management of red tide in oligotrophic waters are poorly understood as most studies on red tide were focused on eutrophic areas. In this study, 404 red tide events together with the historical water quality dynamics during 1991-2020 were investigated in an anthropogenically influenced bay in China - Mirs Bay, whose most region is oligotrophic except small inshore areas. Red tides of oligotrophic offshore accounted for 20 % of all. With the effective governmental management on inshore areas, concentration of PO4 and DIN has been decreased to a low level (PO4 <0.01 mg/L while DIN <0.1 mg/L) in the bay since about 2000. However, the reduction of nutrients was still accompanied by the frequent outbreaks of red tides, as well as a shift of dominant algae from diatoms to dinoflagellates, which might be due to the unbalanced nutrient reduction, such as N:P ratio fluctuation and organic nutrient increase. This shift might trigger more red tide events and even some super ones (long-duration or large-scale) in oligotrophic areas. Detailed analysis on red tide events combined with model simulation proved that the outbreak of red tide in Mirs Bay was caused by the joint contribution of nutrients and hydrodynamics. Nutrients of inshore area supported the red tides there, and with the help of physical conditions, red tides inshore could be transferred to offshore areas and then were likely to bloom again or be preyed to support blooms of other organisms. This study acknowledged that the reduction of both N and P either inorganic or organic nutrients was essential to control red tides, even in oligotrophic waters, but a balanced strategy considering the dual reduction of both nitrogen and phosphorus was of pivotal role to restore the health of coastal water systems disturbed by human.
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Affiliation(s)
- Shuangliang Dai
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
| | - Yanyan Zhou
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China
| | - Na Li
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
| | - Xian-Zhong Mao
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China.
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Jiang M, Gao L, Huang R, Lin X, Gao G. Differential responses of bloom-forming Ulva intestinalis and economically important Gracilariopsis lemaneiformis to marine heatwaves under changing nitrate conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 840:156591. [PMID: 35688236 DOI: 10.1016/j.scitotenv.2022.156591] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/07/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
Marine heatwaves (MHWs) are affecting the survival of macroalgae. However, little is known regarding how the impacts of MHWs are regulated by nitrogen availability. In this study, we investigated the physiological and genetic responses of a green-tide macroalga Ulva intestinalis Linnaeus and a commercially cultivated macroalga Gracilariopsis lemaneiformis (Bory) E.Y. Dawson, Acleto & Foldvik under different nitrate conditions to simulated MHWs. Under nitrogen limited conditions (LN), heatwaves did not significantly affect biomass or Fv/Fm of U. intestinalis although it led to an earlier biomass decline due to more reproduction events, and meanwhile an upregulation in genes related to TCA cycle and oxidative phosphorylation was detected, supporting sporulation. Under nitrogen replete conditions (HN), heatwaves did not change biomass, Fv/Fm or photosynthetic pigments but reduced reproduction rate along with insignificant change of oxidative phosphorylation and TCA cycle related genes. Meanwhile, genes related to photosynthesis and glutathione metabolism were upregulated. Regarding G. lemaneiformis, heatwaves reduced its Fv/Fm and photosynthetic pigments content, leading to bleaching and death, and photosynthesis-related genes were also downregulated at LN. Fv/Fm was improved and photosynthesis-related genes were up-regulated by the combination of nitrogen enrichment and heatwaves, whereas G. lemaneiformis remained bleached and died by day 12. Therefore, U. intestinalis could survive heatwaves through shifting to micropropagules at LN and protecting its photosynthesis at HN. In contrast, G. lemaneiformis died of bleaching when suffering heatwaves regardless of nitrogen availability. These findings suggest that in future oceans with eutrophication and MHWs, the harmful alga U. intestinalis may have more advantages over the economic alga G. lemaneiformis.
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Affiliation(s)
- Meijia Jiang
- State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China
| | - Lin Gao
- State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China
| | - Ruiping Huang
- State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China
| | - Xin Lin
- State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China
| | - Guang Gao
- State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China.
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Optimisation of Biomass Production and Nutritional Value of Two Marine Diatoms (Bacillariophyceae), Skeletonema costatum and Chaetoceros calcitrans. BIOLOGY 2022; 11:biology11040594. [PMID: 35453793 PMCID: PMC9024967 DOI: 10.3390/biology11040594] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/28/2022] [Accepted: 04/12/2022] [Indexed: 11/30/2022]
Abstract
Simple Summary One of the key constraints that is associated with the production of microalgae biomass and products, is the low yields that are associated with high production costs in microalgae cultivation units. Therefore, the aim of the present work was to improve the biomass productivity of two high-value diatom species, Skeletonema costatum and Chaetoceros calcitrans. To do so, the culture medium that was supplied to the cultures was optimised in a stepwise process, regarding the nutrient’s silicate, nitrate, phosphorus, iron, and micronutrients. For both diatoms, the results that were obtained revealed a significant increase in biomass productivity as well as an improved biochemical profile regarding increased omega-3 fatty acids contents. With this work, the optimise culture media was established for each diatom, thus providing a strategy for lower production costs that were reflected in higher productivities with higher biomass quality. Ultimately this will help improve the application of S. costatum and C. calcitrans in the aquaculture and nutraceutical industries. Abstract S. costatum and C. calcitrans are two cosmopolitan high-value centric diatoms, with a rich nutritional profile. The following work optimised the culture medium of S. costatum and C. calcitrans cultures, respectively, in a stepwise process as follows: 2.4 mM and 1.2 mM of silicate, 4 mM of nitrate, 100 µM of phosphate, 20 and 80 µM iron, and 0.5 mL L−1 of micronutrients. The results that were obtained revealed an increase in biomass productivity with a 1.8- and 3.2-fold increase in biomass that was produced by S. costatum and C. calcitrans, respectively. The biochemical profile showed an increase in high-value PUFAs such as 2.6-fold and 2.3-fold increase in EPA for S. costatum and C. calcitrans, respectively, whilst a 2.6-fold increase in DHA was detected in S. costatum cultures. The present work provides the basic tools for the industrial cultivation of S. costatum and C. calcitrans with enhanced productivity as well as improved biomass quality, two factors which are highly relevant for a more effective application of these diatoms to aquaculture and nutraceutical production.
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Qiu J, Su T, Wang X, Jiang L, Shang Y, Jin P, Xu J, Fan J, Li W, Li F. Comparative study of the physiological responses of Skeletonema costatum and Thalassiosira weissflogii to initial pCO 2 in batch cultures, with special reference to bloom dynamics. MARINE ENVIRONMENTAL RESEARCH 2022; 175:105581. [PMID: 35151949 DOI: 10.1016/j.marenvres.2022.105581] [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: 08/14/2021] [Revised: 01/30/2022] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
Extensive studies have documented the responses of diatoms to environmental drivers in the context of climate change. However, bloom dynamics are usually ignored in most studies. Here, we investigated the effects of the initial pCO2 on the bloom characteristics of two cosmopolitan diatoms, Skeletonema costatum and Thalassiosira weissflogii. Batch cultures with two initial pCO2 conditions (LC: 400 μatm; HC: 1000 μatm) were used to investigate bloom dynamics under current and ocean acidification scenarios. The simulated S. costatum bloom was characterized by fast accumulation, a rapid decline in biomass, and a shorter stationary phase. The T. weissflogii bloom had a longer stationary phase, and cell density remained at high levels after culturing for 19 days. The physiological performances of the two diatoms varied significantly in the different bloom phases. We found that the initial pCO2 has modulating effects on biomass accumulation and bloom dynamics for these two diatoms. The higher initial pCO2 enhanced the specific growth rate of T. weissflogii by 6% in the exponential phase, leading to higher cell densities, while 86% higher decay rates were observed in the HC cultures of S. costatum. Overall, ocean acidification may alter the dynamics of diatom blooms and may have profound impacts on the biological carbon pump.
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Affiliation(s)
- Jingmin Qiu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China; Jiangsu Institute of Marine Resources Development, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Tianci Su
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Xin Wang
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Lele Jiang
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Yu Shang
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Peng Jin
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Juntian Xu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Jiale Fan
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China
| | - Wei Li
- College of Life and Environment Sciences, Huangshan University, Huangshan, 245041, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China
| | - Futian Li
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang, 222005, China; Jiangsu Institute of Marine Resources Development, Jiangsu Ocean University, Lianyungang, 222005, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China.
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7
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Yan F, Li L, Yu D, Cui C, Zang S, Xu Z, Wu H. Physiological Responses of Sargassum muticum, a Potential Golden Tide Species, to Different Levels of Light and Nitrogen. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.759732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sargassum golden tides have bloomed frequently in many sea areas throughout the world, and negatively impacted on the local marine ecology. Sargassum muticum commonly inhabits rocky shores. It is now distributed worldwide due to its invasiveness, and recently drifting individuals have been observed on the coasts of Canary Islands. However, as a potential golden tide alga, physiological, and ecological studies of this species have not been frequently explored. To investigate the responses of S. muticum to light and nitrogen, two key environmental factors in golden tide formation, we established three light levels (LL, low light, 10 μmol photons m–2 s–1; ML, medium light, 60 μmol photons m–2 s–1, and HL, high light, 300 μmol photons m–2 s–1) and two nitrogen levels (LN, low nitrogen, 25.0 μM of natural seawater; HN, high nitrogen, 125.0 μM), and cultivated the thalli under different conditions for 12 days before measuring the physiological properties of alga. The results showed that higher light and/or nitrogen levels enhanced the relative algal growth rate. The maximum net photosynthesis rate of alga increased with the light, while it remained unaffected by the nitrogen. The HN treatment had no effect on the apparent photosynthetic efficiency of algae in the LL culture, while increased it in the ML and HL cultures. The irradiance saturation point of photosynthesis was approximately 300 μmol photons m–2 s–1 with no significant difference among the six treatments, except for a slight increase under HLHN in contrast to the LLHN and MLLN treatments. HL treatment decreased the maximum quantum yield of photosynthesis (Fv/Fm) in both nitrogen levels. In the HN culture, ML and HL led to lower values of photoinhibition, indicating higher survivability in the alga. The HN culture led to higher nitrogen uptake but had no effects on Fv/Fm and the contents of pigments and soluble protein, regardless of culture light level. Based on these results, we speculate that drifting individuals of S. muticum would be possible to form a golden tide owing to its rapid growth rate at light level of 300 μmol photons m–2 s–1, when they encountered the sustained lower light level on the sea surface (≤300 μmol photons m–2 s–1). A high nitrogen supply caused by eutrophication of seawater might facilitate this process. Our results provide an important reference for the prediction of golden tides formed by S. muticum.
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8
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Ji F, Sun Y, Ma Q, Feng X, Mi D. Response of planktonic communities to environmental stress in the eutrophic waters of Xiaoping Island in China. CHEMOSPHERE 2021; 275:130107. [PMID: 33984899 DOI: 10.1016/j.chemosphere.2021.130107] [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: 12/08/2020] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
Phytoplankton blooms were affected by external environmental nutrient input, while the interspecific interactions in plankton (phytoplankton and mesozooplankton) under the nutrient pollution gradient remain largely unknown. Here, we systematically collected samples for 9 months (from April to December 2018) in the coastal waters of Xiaoping Island in China to analyze the planktonic community structure and identify the main driving environmental factors along the nutrient gradient from the sewage outlet to the open sea. The results indicated that there existed obvious seasonal and spatial variations in the planktonic community. Procrustes test analysis showed that temperature, transparency, dissolved oxygen, nitrate (NO3-N), phosphate (PO4-P), and silicate (SiO3-Si) significantly affected the community compositions and diversity of plankton (p < 0.05). Co-occurrence network showed that seasons and nutrients pollution had an important influence on the inter-specific interactions between phytoplankton and mesozooplankton. In different nutrient pollution gradients, diatom was the most associated with Copepods in Section 1 (9.38%), Section 2 (9.84%), and Section 3 (5.38%), respectively, and it was also associated with Planktonic larva in Section 1 (7.81%), followed by in Section 3 (4.30%) and 2 (1.64%). Dinoflagellates were associated with Chaetognatha only in Section 1 (4.69%). This study may provide new insights into the plankton dynamics and facilitate nearshore environmental management.
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Affiliation(s)
- Fengyun Ji
- Institute of Environmental Systems Biology, Environment Science and Engineering College, Dalian Maritime University, Dalian, Liaoning Province, 116026, China
| | - Yeqing Sun
- Institute of Environmental Systems Biology, Environment Science and Engineering College, Dalian Maritime University, Dalian, Liaoning Province, 116026, China.
| | - Qiao Ma
- Institute of Environmental Systems Biology, Environment Science and Engineering College, Dalian Maritime University, Dalian, Liaoning Province, 116026, China
| | - Xiangda Feng
- Institute of Environmental Systems Biology, Environment Science and Engineering College, Dalian Maritime University, Dalian, Liaoning Province, 116026, China
| | - Dong Mi
- College of Science, Dalian Maritime University, Dalian, Liaoning Province, 116026, China
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9
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Gao G, Liu W, Zhao X, Gao K. Ultraviolet Radiation Stimulates Activity of CO 2 Concentrating Mechanisms in a Bloom-Forming Diatom Under Reduced CO 2 Availability. Front Microbiol 2021; 12:651567. [PMID: 33796095 PMCID: PMC8008072 DOI: 10.3389/fmicb.2021.651567] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 02/26/2021] [Indexed: 11/22/2022] Open
Abstract
The diatom Skeletonema costatum is cosmopolitan and forms algal blooms in coastal waters, being exposed to varying levels of solar UV radiation (UVR) and reduced levels of carbon dioxide (CO2). While reduced CO2 availability is known to enhance CO2 concentrating mechanisms (CCMs) in this diatom and others, little is known on the effects of UV on microalgal CCMs, especially when CO2 levels fluctuate in coastal waters. Here, we show that S. costatum upregulated its CCMs in response to UVR (295–395 nm), especially to UVA (320–395 nm) in the presence and absence of photosynthetically active radiation (PAR). The intensity rise of UVA and/or UVR alone resulted in an increase of the activity of extracellular carbonic anhydrase (CAe); and the addition of UVA enhanced the activity of CCMs-related CAe by 23–27% when PAR levels were low. Such UV-stimulated CCMs activity was only significant at the reduced CO2 level (3.4 μmol L−1). In addition, UVA alone drove active HCO3− uptake although it was not as obvious as CAe activity, another evidence for its role in enhancing CCMs activity. In parallel, the addition of UVA enhanced photosynthetic carbon fixation only at the lower CO2 level compared to PAR alone. In the absence of PAR, carbon fixation increased linearly with increased intensities of UVA or UVR regardless of the CO2 levels. These findings imply that during S. costatum blooming period when CO2 and PAR availability becomes lower, solar UVR (mainly UVA) helps to upregulate its CCMs and thus carbon fixation, enabling its success of frequent algal blooms.
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Affiliation(s)
- Guang Gao
- State Key Laboratory of Marine Environmental Science and College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Wei Liu
- Department of Technology and Resource Management, Guangdong Jiangmen Chinese White Dolphin Provincial Nature Reserve Management Bureau, Jiangmen, China
| | - Xin Zhao
- State Key Laboratory of Marine Environmental Science and College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science and College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
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10
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Qiao H, Zang S, Yan F, Xu Z, Wang L, Wu H. Physiological responses of the diatoms Thalassiosira weissflogii and Thalassiosira pseudonana to nitrogen starvation and high light. MARINE ENVIRONMENTAL RESEARCH 2021; 166:105276. [PMID: 33578138 DOI: 10.1016/j.marenvres.2021.105276] [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: 11/05/2020] [Revised: 01/24/2021] [Accepted: 01/30/2021] [Indexed: 06/12/2023]
Abstract
As oceans warm, the depth of the upper mixed layer is predicted to decrease, resulting in insufficient nutrient supply and higher solar radiation for phytoplankton. In order to understand the photophysiological responses of the key eukaryotic phytoplankton diatoms to high light and nutrient limitation, we grew two diatoms, Thalassiosira weissflogii and Thalassiosira pseudonana under N starvation conditions and exposed them to high visible light. It showed that the large-sized diatom T. weissflogii can maintain photosynthetic activity for a longer period of time under nitrogen starvation as compared with the small-sized diatom T. pseudonana. The electron transfer reaction was inhibited in both diatoms and the fast closing of reaction centers promoted the development of QB non-reducing PSII centers, thus facilitated the rapid induction of NPQ, however, the induction of NPQ depended on the degree of N starvation. N starvation exacerbated the photoinhibition caused by high light. The smaller-sized T. pseudonana had a higher σi value and was more sensitive to high-light, but its PSII repair rate was also higher. In contrast, T. weissflogii was more tolerant to high light with a lower σi value, but the tolerance was severely reduced under N-starvation. This study provides helpful insight into how climate change variables impact diatom's photosynthetic physiology.
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Affiliation(s)
- Hongjin Qiao
- School of Life Science, Ludong University, Yantai, 264025, China; Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University,Yantai, 264025, China
| | - Shasha Zang
- School of Life Science, Ludong University, Yantai, 264025, China; Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University,Yantai, 264025, China
| | - Fang Yan
- School of Life Science, Ludong University, Yantai, 264025, China; Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University,Yantai, 264025, China
| | - Zhiguang Xu
- School of Life Science, Ludong University, Yantai, 264025, China; Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University,Yantai, 264025, China
| | - Lei Wang
- School of Life Science, Ludong University, Yantai, 264025, China; Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University,Yantai, 264025, China
| | - Hongyan Wu
- School of Life Science, Ludong University, Yantai, 264025, China; Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University,Yantai, 264025, China.
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11
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Gao G, Zhao X, Jin P, Gao K, Beardall J. Current understanding and challenges for aquatic primary producers in a world with rising micro- and nano-plastic levels. JOURNAL OF HAZARDOUS MATERIALS 2021; 406:124685. [PMID: 33321322 DOI: 10.1016/j.jhazmat.2020.124685] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 11/22/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
The impacts of micro- and nanoplastics (MNPs) on aquatic animals have been intensively studied; however, the extent and magnitude of potential effects of MNPs on aquatic primary producers are poorly understood. In this study, we quantitatively analyzed the published literature to examine the impacts of MNPs on growth, photosynthesis, pigments, and metabolism of aquatic microalgae. MNPs negatively affected growth of microalgae but usually had a high EC50 (>25 mg/L). However, positively charged MNPs had a much lower EC50 (<1 mg/L). MNPs lowered maximum photochemical efficiency of photosystem II (Fv/Fm) with the effect increasing with concentration of MNPs but diminishing with exposure time, and also reduced chlorophyll a content to enhanced extent with increased MNPs concentration. MNPs induced relatively higher changes in superoxide dismutase (SOD) and malondialdehyde (MDA) levels in marine algae than in freshwater algae. Reactive oxygen species (ROS) levels increased with MNPs concentration and exposure time while SOD levels first increased and then decreased with increasing MNPs concentration. Macrophytes were found to be able to trap MNPs via multiple mechanisms. Future work should focus on the mechanisms behind MNPs impacts on primary productivity and global carbon cycle, and the combined effects of MNPs with other environmental factors.
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Affiliation(s)
- Guang Gao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China.
| | - Xin Zhao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China
| | - Peng Jin
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China
| | - John Beardall
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China; School of Biological Sciences, Monash University, Clayton, VI 3800, Australia
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12
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Wang B, Chen M, Zheng M, Qiu Y. Responses of Two Coastal Algae (Skeletonema costatum and Chlorella vulgaris) to Changes in Light and Iron Levels 1. JOURNAL OF PHYCOLOGY 2020; 56:618-629. [PMID: 31965566 DOI: 10.1111/jpy.12972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/17/2019] [Indexed: 06/10/2023]
Abstract
Iron (Fe) is essential for phytoplankton growth and photosynthesis, and is proposed to be an important factor regulating algal blooms under replete major nutrients in coastal environments. Here, Skeletonema costatum, a typical red-tide diatom species, and Chlorella vulgaris, a widely distributed Chlorella, were chosen to examine carbon fixation and Fe uptake by coastal algae under dark and light conditions with different Fe levels. The cellular carbon fixation and intracellular Fe uptake were measured via 14 C and 55 Fe tracer assay, respectively. Cell growth, cell size, and chlorophyll-α concentration were measured to investigate the algal physiological variation in different treatments. Our results showed that cellular Fe uptake proceeds under dark and the uptake rates were comparable to or even higher than those in the light for both algal species. Fe requirements per unit carbon fixation were also higher in the dark resulting in higher Fe: C ratios. During the experimental period, high Fe addition significantly enhanced cellular carbon fixation and Fe uptake. Compared to C. vulgaris, S. costatum was the common dominant bloom species because of its lower Fe demand but higher Fe uptake rate. This study provides some of the first measurements of Fe quotas in coastal phytoplankton cells, and implies that light and Fe concentrations may influence the phytoplankton community succession when blooms occur in coastal ecosystems.
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Affiliation(s)
- Bo Wang
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Min Chen
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Minfang Zheng
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Yusheng Qiu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
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13
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Gao G, Wu M, Fu Q, Li X, Xu J. A two-stage model with nitrogen and silicon limitation enhances lipid productivity and biodiesel features of the marine bloom-forming diatom Skeletonema costatum. BIORESOURCE TECHNOLOGY 2019; 289:121717. [PMID: 31279322 DOI: 10.1016/j.biortech.2019.121717] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 06/25/2019] [Accepted: 06/26/2019] [Indexed: 06/09/2023]
Abstract
To enhance biodiesel production and quality from a bloom-forming diatom Skeletonema costatum, a two-stage model, in which cells were cultured in nutrient replete conditions first and then transferred to nutrient limitation conditions, was explored. Compared to one-stage model, nutrient limitation in the second stage significantly increased lipid content in spite of decreasing growth; consequently, Si-limitation and N-Si-limitation respectively increased lipid productivity by 37.6% and 76.7% for 6 h induction, and 42.8% and 113.7% for 12 induction. Nutrient limitation enhanced the proportions of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) but reduced polyunsaturated fatty acid (PUFA). Therefore, N-Si-limitation reduced iodine value by 33.7% and 45.6% but increased cetane number by 6.4% and 21.6% for 6 and 24 h induction, respectively. These findings indicate that the two-stage model with N-Si-limitation can enhance lipid productivity as well as biodiesel quality from diatoms.
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Affiliation(s)
- Guang Gao
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang 222005, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China
| | - Min Wu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang 222005, China
| | - Qianqian Fu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang 222005, China
| | - Xinshu Li
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang 222005, China
| | - Juntian Xu
- Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang 222005, China; Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Lianyungang 222005, China; Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang 222005, China.
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Cai Y, Cao Y, Tang C. Evidence for the Primary Role of Phytoplankton on Nitrogen Cycle in a Subtropical Reservoir: Reflected by the Stable Isotope Ratios of Particulate Nitrogen and Total Dissolved Nitrogen. Front Microbiol 2019; 10:2202. [PMID: 31608034 PMCID: PMC6773875 DOI: 10.3389/fmicb.2019.02202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 09/09/2019] [Indexed: 01/10/2023] Open
Abstract
Knowledge about the primary factor controlling stable isotope ratios of particulate nitrogen (δ15NPN) and total dissolved nitrogen (δ15NTDN) in a subtropical reservoir can improve the understanding of regional and global nitrogen cycles. Taking Lianhe Reservoir as a representative subtropical reservoir, we studied the spatial and temporal distributions of δ15NPN andδ15NTDN and their relationships with the surrounding physicochemical factors and phytoplankton. The results showed that variations in δ15NPN and δ15NTDN followed seasonal thermal cycles. The values of δ15NTDN were inversely proportional to those of δ15NPN. PCA showed that phytoplankton cell density and pH were the primary drivers of the variation of δ15NPN (45.2%). The primary factors influencing δ15NTDN were Chl a and phytoplankton cell density, which both indicated phytoplankton biomass. We also determined that the dominant species was Microcystis densa during the thermal stratification period and Staurodesmus aristiferus during the mixing period. Laboratory experiments showed that δ15NPN values in both M. densa (from 19.5 to 14.6‰) and S. aristiferus (from 19.4 to 16.0 ‰) media decreased significantly as the algal cells grew. Furthermore, the δ15NTDN values increased from 4.9 to 7.9‰ and from 4.7 to 6.9‰ in M. densa and S. aristiferus media, respectively, when the δ15NPN values decreased. These experimental results were consistent with field investigation results and indicated that variations in δ15NPN and δ15NTDN were mainly controlled by phytoplankton cell density, especially the cell density of the dominant species, in both the thermal stratification and mixing periods. The results also suggested that cell density, not phytoplankton species, was the key factor regulating the distribution of nitrogen stable isotopes. These results together indicated that phytoplankton cell density is the primary factor in the regulation of nitrogen stable isotope composition and that its influence is greater than that of other physical and chemical factors. This study provided detailed information supporting the primary role of phytoplankton in the nitrogen geochemical cycle and improved the understanding of biochemical processes in natural subtropical reservoirs.
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Affiliation(s)
- Yangyang Cai
- School of Environmental Sciences and Engineering, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou, China
| | - Yingjie Cao
- School of Environmental Sciences and Engineering, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou, China
| | - Changyuan Tang
- School of Environmental Sciences and Engineering, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou, China.,School of Geography and Planning, Sun Yat-sen University, Guangzhou, China
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