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Li L, Song X, Wang Z, Wan M, Ni G, Tan Y, Li G. Nitrogen enrichment ameliorates the stimulatory effects of reduced salinity on photosynthesis and growth of phytoplankton assemblages in the northern South China sea. MARINE ENVIRONMENTAL RESEARCH 2023; 192:106249. [PMID: 37924795 DOI: 10.1016/j.marenvres.2023.106249] [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: 09/15/2023] [Revised: 10/28/2023] [Accepted: 10/30/2023] [Indexed: 11/06/2023]
Abstract
Anthropogenic activities and climate change are exacerbating the occurrence of extreme rainfall that normally brings large amounts of nutrient-rich freshwater from the land to the sea, resulting in acute salinity decrease and nutrient increase. To evaluate the effects of such changes in salinity and nutrients, we tracked the changes in photosynthetic efficiency and growth of phytoplankton assemblages from the northern South China Sea at 5 salinity levels and at an intermediate salinity level with 3 or 4 nitrogen concentrations. The results showed that the reduction of salinity reduced the maximum photochemical quantum yield (FV/FM) of photosystem II of phytoplankton within a short-term cultivation (i.e. 24-72 h), followed by a stimulatory effect. The reducing effect of reduced salinity lasted longer in the nearshore area than in the offshore area, so the stimulatory effect occurred later in the former area. Nitrogen enrichment mitigated the negative effect of reduced salinity in short-term cultivation and showed a positive effect on FV/FM in long-term cultivation. Moreover, both reduced salinity and enriched nitrogen stimulated phytoplankton growth after an acclimation period. Our results suggest that the reduced salinity stresses phytoplankton in the short term, which is mitigated by nitrogen enrichment, but benefits them in the long term. This sheds light on how phytoplankton thrive and even flourish in coastal or estuarine environments where salinity and nutrients typically covary strongly after extreme rainfall.
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Affiliation(s)
- Li Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510530, China; Key Laboratory of Science and Technology on Operational Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xingyu Song
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510530, China; Key Laboratory of Science and Technology on Operational Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhiqin Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510530, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mingyue Wan
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510530, China; Key Laboratory of Science and Technology on Operational Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guangyan Ni
- Key Laboratory of Science and Technology on Operational Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yehui Tan
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510530, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Gang Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510530, China; Key Laboratory of Science and Technology on Operational Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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Lacour T, Larivière J, Ferland J, Morin PI, Grondin PL, Donaher N, Cockshutt A, Campbell DA, Babin M. Photoacclimation of the polar diatom Chaetoceros neogracilis at low temperature. PLoS One 2022; 17:e0272822. [PMID: 36125987 PMCID: PMC9488821 DOI: 10.1371/journal.pone.0272822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 07/26/2022] [Indexed: 11/18/2022] Open
Abstract
Polar microalgae face two major challenges: 1- growing at temperatures (-1.7 to 5°C) that limit enzyme kinetics; and 2- surviving and exploiting a wide range of irradiance. The objective of this study is to understand the adaptation of an Arctic diatom to its environment by studying its ability to acclimate to changes in light and temperature. We acclimated the polar diatom Chaetoceros neogracilis to various light levels at two different temperatures and studied its growth and photosynthetic properties using semi-continuous cultures. Rubisco content was high, to compensate for low catalytic rates, but did not change detectably with growth temperature. Contrary to what is observed in temperate species, in C. neogracilis, carbon fixation rate (20 min 14C incorporation) equaled net growth rate (μ) suggesting very low or very rapid (<20 min) re-oxidation of the newly fixed carbon. The comparison of saturation irradiances for electron transport, oxygen net production and carbon fixation revealed alternative electron pathways that could provide energy and reducing power to the cell without consuming organic carbon which is a very limiting product at low temperatures. High protein contents, low re-oxidation of newly fixed carbon and the use of electron pathways alternative to carbon fixation may be important characteristics allowing efficient growth under those extreme environmental conditions.
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Affiliation(s)
- Thomas Lacour
- Ifremer, PHYTOX, PHYSALG, Brest, France
- Département de Biologie, Takuvik International Research Laboratory (IRL-3376, CNRS (France) & ULaval (Canada), Université Laval, Québec, Canada
- * E-mail:
| | - Jade Larivière
- Département de Biologie, Takuvik International Research Laboratory (IRL-3376, CNRS (France) & ULaval (Canada), Université Laval, Québec, Canada
| | - Joannie Ferland
- Département de Biologie, Takuvik International Research Laboratory (IRL-3376, CNRS (France) & ULaval (Canada), Université Laval, Québec, Canada
| | - Philippe-Israël Morin
- Département de Biologie, Takuvik International Research Laboratory (IRL-3376, CNRS (France) & ULaval (Canada), Université Laval, Québec, Canada
| | - Pierre-Luc Grondin
- Département de Biologie, Takuvik International Research Laboratory (IRL-3376, CNRS (France) & ULaval (Canada), Université Laval, Québec, Canada
| | - Natalie Donaher
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, Canada
| | - Amanda Cockshutt
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, Canada
| | - Douglas A. Campbell
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, Canada
| | - Marcel Babin
- Département de Biologie, Takuvik International Research Laboratory (IRL-3376, CNRS (France) & ULaval (Canada), Université Laval, Québec, Canada
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Ma J, Wang P, Hu B, Wang X, Qian J. Synergistic promoting effect of increasing aquatic ammonium and CO 2 on Microcystis aeruginosa. CHEMOSPHERE 2022; 301:134553. [PMID: 35405194 DOI: 10.1016/j.chemosphere.2022.134553] [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: 11/11/2021] [Revised: 03/13/2022] [Accepted: 04/05/2022] [Indexed: 06/14/2023]
Abstract
Owing to climate change and intensive agricultural development, freshwater bodies have been affected by increases in both CO2 levels and chemically-reduced forms of N. However, little is known about how these changes affect cyanobacterial growth and blooms. This study explored a range of light conditions (30, 80, 130, or 200 μmol photons/m2/s) wherein Microcystis aeruginosa, a widespread bloom-forming species, was exposed to different concentrations of CO2 (400 parts per million (ppm) and 1000 ppm) in a medium containing NH4+ or NO3-. The interactive effects of N sources and CO2 levels on the C/N metabolic balance and energy balance were examined to assess changes in the growth of M. aeruginosa. When the light intensity was 80 μmol photons/m2/s, elevated CO2 could reduce intracellular reactive oxygen species (ROS) in NH4+-grown M. aeruginosa. Meanwhile, cell density and chlorophyll a (Chl a) increased with increasing CO2 levels, and the increase in Chl a was significantly greater in NH4+-grown M. aeruginosa than in NO3--grown M. aeruginosa. Under light conditions of 200 μmol photons/m2/s, elevated CO2 concentration caused NO3--grown M. aeruginosa to be affected by a large amount of ROS, and the growth of NO3--grown M. aeruginosa was finally suppressed. However, NH4+-grown M. aeruginosa had a smaller amount of ROS and showed improved growth as CO2 was elevated. This difference can be attributed to the faster metabolic pathways in the NH4+ environment, which manifested in a lower accumulation of 2-oxoglutarate and fatty acids as CO2 was elevated. These findings suggest that the simultaneous increase in ammonium and CO2 in aquatic ecosystems confers cyanobacteria with greater advantages than the combination of nitrate and CO2, which may aggravate cyanobacterial blooms.
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Affiliation(s)
- Jingjie Ma
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, People's Republic of China; College of Environment, Hohai University, Nanjing, 210098, People's Republic of China
| | - Peifang Wang
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, People's Republic of China; College of Environment, Hohai University, Nanjing, 210098, People's Republic of China.
| | - Bin Hu
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, People's Republic of China; College of Environment, Hohai University, Nanjing, 210098, People's Republic of China
| | - Xun Wang
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, People's Republic of China; College of Environment, Hohai University, Nanjing, 210098, People's Republic of China
| | - Jin Qian
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, People's Republic of China; College of Environment, Hohai University, Nanjing, 210098, People's Republic of China
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Xu D, Tong S, Wang B, Zhang X, Wang W, Zhang X, Fan X, Wang Y, Sun K, Ye N. Ocean acidification stimulation of phytoplankton growth depends on the extent of departure from the optimal growth temperature. MARINE POLLUTION BULLETIN 2022; 177:113510. [PMID: 35299145 DOI: 10.1016/j.marpolbul.2022.113510] [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: 11/04/2021] [Revised: 01/23/2022] [Accepted: 02/25/2022] [Indexed: 06/14/2023]
Abstract
Ocean acidification and warming are two major environmental stressors; however, the generality of how warming will alter growth responses of phytoplankton to ocean acidification is less known. Here, enhancement of growth by high CO2 (HC) in Phaeodactylum tricornutum and Thalassiosira weissflogii was most prominent at optimum temperature. The extent to which growth rates in HC cultures were raised compared to low CO2 (LC) cultures tended to decrease with increasing or decreasing temperature, compared to the optimum. Further mechanistic studies in P. tricornutum revealed that cellular carbon and nitrogen content, superoxide dismutase activity, and respiration were generally higher in HC than those in LC at high and low temperatures, whereas PSII photochemical parameters were generally lower in HC than in LC at high and low temperatures. These results indicate that HC-grown cells needed to invest more energy and materials to maintain intracellular homeostasis and repair damage induced by the unsuitable temperatures.
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Affiliation(s)
- Dong Xu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Shanying Tong
- College of Life Science, Ludong University, Yantai, China
| | - Bingkun Wang
- School of Environment, Harbin Institute of Technology, Harbin, China
| | - Xiansheng Zhang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Wei Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Xiaowen Zhang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Xiao Fan
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Yitao Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Ke Sun
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Naihao Ye
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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5
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Berthold M, Campbell DA. Restoration, conservation and phytoplankton hysteresis. CONSERVATION PHYSIOLOGY 2021; 9:coab062. [PMID: 34394942 PMCID: PMC8361504 DOI: 10.1093/conphys/coab062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 06/10/2021] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
Phytoplankton growth depends not only upon external factors that are not strongly altered by the presence of phytoplankton, such as temperature, but also upon factors that are strongly influenced by activity of phytoplankton, including photosynthetically active radiation, and the availability of the macronutrients carbon, nitrogen, phosphorus and, for some, silicate. Since phytoplankton therefore modify, and to an extent create, their own habitats, established phytoplankton communities can show resistance and resilience to change, including managed changes in nutrient regimes. Phytoplankton blooms and community structures can be predicted from the overall biogeochemical setting and inputs, but restorations may be influenced by the physiological responses of established phytoplankton taxa to nutrient inputs, temperature, second-order changes in illumination and nutrient recycling. In this review we discuss the contributions of phytoplankton ecophysiology to biogeochemical hysteresis and possible effects on community composition in the face of management, conservation or remediation plans.
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Affiliation(s)
- Maximilian Berthold
- Department of Biology, Mount Allison University, Sackville, New Brunswick E4L 1C9, Canada
| | - Douglas A Campbell
- Department of Biology, Mount Allison University, Sackville, New Brunswick E4L 1C9, Canada
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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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7
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Li Z, Lan T, Zhang J, Gao K, Beardall J, Wu Y. Nitrogen Limitation Decreases the Repair Capacity and Enhances Photoinhibition of Photosystem II in a Diatom. Photochem Photobiol 2021; 97:745-752. [PMID: 33496343 DOI: 10.1111/php.13386] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 01/30/2023]
Abstract
Macronutrient limitation and increased solar exposure coincide with ocean warming-enhanced stratification, with consequences for phytoplankton within the upper mixing layer. In this study, we grew a diatom, Thalassiosira punctigera, under nitrogen-limited and replete conditions for more than 14 generations and investigated both the biochemical composition of treated cells and their photochemical responses to high light and UV exposure. The photosynthetic pigment and the particulate organic nitrogen (PON) content significantly decreased in the low nitrate grown cells, with drastic decline of the absorption of UV absorbing compounds. Under an acute exposure to high light or UV radiation, we observed a significant decline in the photochemical yield along with an increase of nonphotosynthetic quenching (NPQ), with the former lowered and the latter raised in the low-nitrogen grown cells. The results reveal a decreased repair rate and enhanced photoinhibition of the diatom under nitrogen limitation when exposed to increased levels of light and UV radiation, suggesting a higher vulnerability of the diatom phytoplankton under influences of oceanic global change.
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Affiliation(s)
- Zhenzhen Li
- College of Marine Science and Fisheries, Jiangsu Ocean University, Lianyungang, China.,The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Ting Lan
- College of Marine Science and Fisheries, Jiangsu Ocean University, Lianyungang, China
| | - Jiaojiao Zhang
- College of Marine Science and Fisheries, Jiangsu Ocean University, Lianyungang, China
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - John Beardall
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China.,School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Yaping Wu
- College of Marine Science and Fisheries, Jiangsu Ocean University, Lianyungang, China
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Ma J, Wang P. Effects of rising atmospheric CO 2 levels on physiological response of cyanobacteria and cyanobacterial bloom development: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:141889. [PMID: 32920383 DOI: 10.1016/j.scitotenv.2020.141889] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/15/2020] [Accepted: 08/20/2020] [Indexed: 05/19/2023]
Abstract
Increasing atmospheric CO2 concentration negatively impacts aquatic ecosystems and may exacerbate the problem of undesirable cyanobacterial bloom development in freshwater ecosystems. Elevated levels of atmospheric CO2 may increase the levels of dissolved CO2 in freshwater systems, via air-water exchanges, enhancing primary production in the water and catchments. Although high CO2 levels improve cyanobacterial growth and increase cyanobacterial biomass, the impacts on their internal physiological processes can be more complex. Here, we have reviewed previous studies to evaluate the physiological responses of cyanobacteria to high concentrations of CO2. In response to high CO2 concentrations, the pressures of inorganic carbon absorption are reduced, and carbon concentration mechanisms are downregulated, affecting the intracellular metabolic processes and competitiveness of the cyanobacteria. Nitrogen and phosphorus metabolism and light utilization are closely related to CO2 assimilation, and these processes are likely to be affected by resource and energy reallocation when CO2 levels are high. Additionally, the responses of diazotrophic and toxic cyanobacteria to elevated CO2 levels were specifically reviewed. The responses of diazotrophic cyanobacteria to elevated CO2 concentrations were found to be inconsistent, probably because of differences in other factors in experimental designs. Toxic cyanobacteria tended to be superior to non-toxic strains at low levels of CO2; however, the specific effects of microcystin on the regulation require further investigation. Furthermore, the effects of increasing CO2 levels on cyanobacterial competitiveness in phytoplankton communities and nutrient cycling in aquatic ecosystems were reviewed. High CO2 concentrations may make cyanobacteria less competitive relative to other algal taxa; however, due to the complexity of natural systems and the specificity of algal species, the dominant positions of the cyanobacteria do not seems to be changed. To better understand cyanobacterial responses to elevated CO2 levels and help control cyanobacterial bloom developments, this review has identified key areas for future research.
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Affiliation(s)
- Jingjie Ma
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Peifang Wang
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
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Qu L, Campbell DA, Gao K. Ocean acidification interacts with growth light to suppress CO 2 acquisition efficiency and enhance mitochondrial respiration in a coastal diatom. MARINE POLLUTION BULLETIN 2021; 163:112008. [PMID: 33461076 DOI: 10.1016/j.marpolbul.2021.112008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 12/27/2020] [Accepted: 12/28/2020] [Indexed: 06/12/2023]
Abstract
Diatom responses to ocean acidification have been documented with variable and controversial results. We grew the coastal diatom Thalassiosira weissflogii under 410 (LC, pH 8.13) vs 1000 μatm (HC, pH 7.83) pCO2 and at different levels of light (80, 140, 220 μmol photons m-2 s-1), and found that light level alters physiological responses to OA. CO2 concentrating mechanisms (CCMs) were down-regulated in the HC-grown cells across all the light levels, as reflected by lowered activity of the periplasmic carbonic anhydrase and decreased photosynthetic affinity for CO2 or dissolved inorganic carbon. The specific growth rate was, however, enhanced significantly by 9.2% only at the limiting low light level. These results indicate that rather than CO2 "fertilization", the energy saved from down-regulation of CCMs promoted the growth rate of the diatom when light availability is low, in parallel with enhanced respiration under OA to cope with the acidic stress by providing extra energy.
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Affiliation(s)
- Liming Qu
- State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University, Xiamen, 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, China; Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang 222005, China.
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Pierella Karlusich JJ, Bowler C, Biswas H. Carbon Dioxide Concentration Mechanisms in Natural Populations of Marine Diatoms: Insights From Tara Oceans. FRONTIERS IN PLANT SCIENCE 2021; 12:657821. [PMID: 33995455 PMCID: PMC8119650 DOI: 10.3389/fpls.2021.657821] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 03/23/2021] [Indexed: 05/08/2023]
Abstract
Marine diatoms, the most successful photoautotrophs in the ocean, efficiently sequester a significant part of atmospheric CO2 to the ocean interior through their participation in the biological carbon pump. However, it is poorly understood how marine diatoms fix such a considerable amount of CO2, which is vital information toward modeling their response to future CO2 levels. The Tara Oceans expeditions generated molecular data coupled with in situ biogeochemical measurements across the main ocean regions, and thus provides a framework to compare diatom genetic and transcriptional flexibility under natural CO2 variability. The current study investigates the interlink between the environmental variability of CO2 and other physicochemical parameters with the gene and transcript copy numbers of five key enzymes of diatom CO2 concentration mechanisms (CCMs): Rubisco activase and carbonic anhydrase (CA) as part of the physical pathway, together with phosphoenolpyruvate carboxylase, phosphoenolpyruvate carboxykinase, and malic enzyme as part of the potential C4 biochemical pathway. Toward this aim, we mined >200 metagenomes and >220 metatranscriptomes generated from samples of the surface layer of 66 globally distributed sampling sites and corresponding to the four main size fractions in which diatoms can be found: 0.8-5 μm, 5-20 μm, 20-180 μm, and 180-2,000 μm. Our analyses revealed that the transcripts for the enzymes of the putative C4 biochemical CCM did not in general display co-occurring profiles. The transcripts for CAs were the most abundant, with an order of magnitude higher values than the other enzymes, thus implying the importance of physical CCMs in diatom natural communities. Among the different classes of this enzyme, the most prevalent was the recently characterized iota class. Consequently, very little information is available from natural diatom assemblages about the distribution of this class. Biogeographic distributions for all the enzymes show different abundance hotspots according to the size fraction, pointing to the influence of cell size and aggregation in CCMs. Environmental correlations showed a complex pattern of responses to CO2 levels, total phytoplankton biomass, temperature, and nutrient concentrations. In conclusion, we propose that biophysical CCMs are prevalent in natural diatom communities.
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Affiliation(s)
- Juan José Pierella Karlusich
- Institut de Biologie de l’ENS, Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
- CNRS Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, Paris, France
| | - Chris Bowler
- Institut de Biologie de l’ENS, Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
- CNRS Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, Paris, France
| | - Haimanti Biswas
- CSIR National Institute of Oceanography, Biological Oceanography Division, Dona Paula, India
- *Correspondence: Haimanti Biswas,
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Divergence of photosynthetic strategies amongst marine diatoms. PLoS One 2020; 15:e0244252. [PMID: 33370327 PMCID: PMC7769462 DOI: 10.1371/journal.pone.0244252] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/07/2020] [Indexed: 11/19/2022] Open
Abstract
Marine phytoplankton, and in particular diatoms, are responsible for almost half of all primary production on Earth. Diatom species thrive from polar to tropical waters and across light environments that are highly complex to relatively benign, and so have evolved highly divergent strategies for regulating light capture and utilization. It is increasingly well established that diatoms have achieved such successful ecosystem dominance by regulating excitation energy available for generating photosynthetic energy via highly flexible light harvesting strategies. However, how different light harvesting strategies and downstream pathways for oxygen production and consumption interact to balance excitation pressure remains unknown. We therefore examined the responses of three diatom taxa adapted to inherently different light climates (estuarine Thalassioisira weissflogii, coastal Thalassiosira pseudonana and oceanic Thalassiosira oceanica) during transient shifts from a moderate to high growth irradiance (85 to 1200 μmol photons m-2 s-1). Transient high light exposure caused T. weissflogii to rapidly downregulate PSII with substantial nonphotochemical quenching, protecting PSII from inactivation or damage, and obviating the need for induction of O2 consuming (light-dependent respiration, LDR) pathways. In contrast, T. oceanica retained high excitation pressure on PSII, but with little change in RCII photochemical turnover, thereby requiring moderate repair activity and greater reliance on LDR. T. pseudonana exhibited an intermediate response compared to the other two diatom species, exhibiting some downregulation and inactivation of PSII, but high repair of PSII and induction of reversible PSII nonphotochemical quenching, with some LDR. Together, these data demonstrate a range of strategies for balancing light harvesting and utilization across diatom species, which reflect their adaptation to sustain photosynthesis under environments with inherently different light regimes.
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Wang P, Ma J, Wang X, Tan Q. Rising atmospheric CO 2 levels result in an earlier cyanobacterial bloom-maintenance phase with higher algal biomass. WATER RESEARCH 2020; 185:116267. [PMID: 32798892 DOI: 10.1016/j.watres.2020.116267] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 06/28/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
The effect of rising atmospheric CO2 on freshwater lakes is a subject of considerable debate. However, it is not clear how rising CO2 concentration affects cyanobacterial bloom development under potential nutrient limitation conditions and if CO2 should be taken into account in making nutrient reduction strategy. To fill the knowledge gaps, this study investigated the spatiotemporal variability in aquatic CO2 concentration (pCO2) from 2006 to 2016 in Lake Taihu, where cyanobacterial blooms often occurred from late spring to the early fall. Lake Taihu is an atmospheric CO2 source in May and November, with only 18% and 11% pCO2-undersaturated areas, respectively. During cyanobacterial bloom in August, 81% of the lake areas are pCO2-undersaturated, absorbing ~ 0.53 t C/h of atmospheric CO2. The results demonstrated that CO2 transfer across air-water interface was important in supporting cyanobacterial bloom development. Besides, Field investigation showed that the chlorophyll a level is significantly positively correlated with supersaturated pCO2 (>13.56 µmol/L) in May, but pCO2 decreases with high chlorophyll a levels in August, suggesting that cyanobacterial growth would be promoted by high pCO2 over a threshold. These observations suggested that the effect of rising atmospheric CO2 on freshwater lakes and cyanobacterial blooms should be paid attention to. Further, when the N- and P-levels are >0.3 mg/L and >0.02 mg/L, respectively, high-pCO2 conditions allow a more rapid growth rate of cyanobacteria via improved nutrient-use efficiency. Moreover, cyanobacteria afford maximum N- or P-use efficiency at lower N- or P-concentrations with high CO2 concentration. This improvement would result in an earlier bloom-maintenance phase and higher cyanobacterial biomass. In this case, nutrient reduction is more imperative under future high CO2 conditions.
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Affiliation(s)
- Peifang Wang
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, China, 210098,; College of Environment, Hohai University, Nanjing, China, 210098.
| | - Jingjie Ma
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, China, 210098,; College of Environment, Hohai University, Nanjing, China, 210098
| | - Xun Wang
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, China, 210098,; College of Environment, Hohai University, Nanjing, China, 210098
| | - Qingqian Tan
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, China, 210098,; College of Environment, Hohai University, Nanjing, China, 210098
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13
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Van de Waal DB, Litchman E. Multiple global change stressor effects on phytoplankton nutrient acquisition in a future ocean. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190706. [PMID: 32200734 PMCID: PMC7133525 DOI: 10.1098/rstb.2019.0706] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2019] [Indexed: 12/13/2022] Open
Abstract
Predicting the effects of multiple global change stressors on microbial communities remains a challenge because of the complex interactions among those factors. Here, we explore the combined effects of major global change stressors on nutrient acquisition traits in marine phytoplankton. Nutrient limitation constrains phytoplankton production in large parts of the present-day oceans, and is expected to increase owing to climate change, potentially favouring small phytoplankton that are better adapted to oligotrophic conditions. However, other stressors, such as elevated pCO2, rising temperatures and higher light levels, may reduce general metabolic and photosynthetic costs, allowing the reallocation of energy to the acquisition of increasingly limiting nutrients. We propose that this energy reallocation in response to major global change stressors may be more effective in large-celled phytoplankton species and, thus, could indirectly benefit large-more than small-celled phytoplankton, offsetting, at least partially, competitive disadvantages of large cells in a future ocean. Thus, considering the size-dependent responses to multiple stressors may provide a more nuanced understanding of how different microbial groups would fare in the future climate and what effects that would have on ecosystem functioning. This article is part of the theme issue 'Conceptual challenges in microbial community ecology'.
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Affiliation(s)
- Dedmer B. Van de Waal
- Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen 6871 CM, The Netherlands
| | - Elena Litchman
- W. K. Kellogg Biological Station, Michigan State University, 3700 E. Gull Lake Drive, Hickory Corners, MI 49060, USA
- Department of Integrative Biology, Michigan State University, 288 Farm Lane, East Lansing, MI 48824, USA
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Ma J, Wang P, Wang X, Xu Y, Paerl HW. Cyanobacteria in eutrophic waters benefit from rising atmospheric CO 2 concentrations. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 691:1144-1154. [PMID: 31466196 DOI: 10.1016/j.scitotenv.2019.07.056] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 07/03/2019] [Accepted: 07/04/2019] [Indexed: 06/10/2023]
Abstract
Rising atmospheric carbon dioxide (CO2) may stimulate the proliferation of cyanobacteria. To investigate the possible physiological responses of cyanobacteria to elevated CO2 at different nutrient levels, Microcystis aeruginosa were exposed to different concentrations of CO2 (400, 1100, and 2200 ppm) under two nutrient regimes (i.e., in nutrient-rich and nutrient-poor media). The results indicated that M. aeruginosa differed in its responses to elevated atmospheric CO2 at different nutrient levels. The light utilization efficiency and photoprotection of photosystem II were improved by elevated CO2, particularly when cells were supplied with abundant nutrients. In nutrient-poor media, both total organic carbon and the polysaccharide/protein ratio of the extracellular polymeric substance increased with elevated CO2, accompanied by high cellular carbon/nitrogen ratios. Besides, cells growing with fewer nutrients were more prone to suffer intracellular acidification with elevated CO2 than those growing with abundant nutrients. Nonetheless, alkaline phosphate activity of cyanobacteria was improved by high CO2, provided that reduced pH was in the optimum range for alkaline phosphate activity. Nitrate reductase activity was inhibited by elevated CO2 regardless of nutrient levels, leading to a reduced nitrate uptake. These changes indicate that the biogeochemical cycling of nutrients would be affected by higher atmospheric CO2 conditions. Overall, cyanobacteria in eutrophic waters may benefit more than in oligotrophic waters from rising atmospheric CO2 concentrations, and evaluations of the influence of rising atmospheric CO2 on algae should account for the nutrient level of the ecosystem.
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Affiliation(s)
- Jingjie Ma
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Peifang Wang
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
| | - Xun Wang
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Yi Xu
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Hans W Paerl
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC 28557, United States
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Song X, Tan M, Xu G, Su X, Liu J, Ni G, Li Y, Tan Y, Huang L, Shen P, Li G. Is phosphorus a limiting factor to regulate the growth of phytoplankton in Daya Bay, northern South China Sea: a mesocosm experiment. ECOTOXICOLOGY (LONDON, ENGLAND) 2019; 28:559-568. [PMID: 31123966 DOI: 10.1007/s10646-019-02049-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/23/2019] [Indexed: 06/09/2023]
Abstract
Previous field investigations implied a potential phosphorus (P)-limitation on the growth of phytoplankton in Daya Bay, a mesotrophic bay in the northern South China Sea. Using a total of 15 mesocosms (3 × 3 × 1.5 m, with ~10.8 m3 natural seawater containing phytoplankton assemblages for each), we found P-enrichment caused no obvious effect on phytoplankton (Chl a) growth across 8-day's cultivation in neither winter nor summer, while nitrogen (N)-enrichment greatly increased Chl a in both seasons. N plus P-enrichment further increased Chl a content. The N- or N plus P-enrichments increased the allocation of nano-Chl a but decreased micro-Chl a in most cases, with no obvious effect by P-alone. Coincided with nutrients effect on Chl a content, N- or N plus P-enrichments significantly enhanced the maximum photochemical quantum yield of Photosystem II (FV/FM) and maximum relative electron transport rate (rETRmax), but declined the non-photochemical quenching (NPQ), as well as the threshold for light saturation of electron transport (EK); again, P-enrichment had no significant effect. Moreover, the absorption cross section for PSII photochemistry (σPSII) and electron transport efficiency (α) increased due to N- or N plus P-enrichments, indicating the increased nutrients enhance the light utilization efficiency through promoting PSII light harvesting ability, and thus to enhance phytoplankton growth. Our findings indicate that N- or N plus P-enrichments rigorously fuel phytoplankton blooms regardless of N:P ratios, making a note of caution on the expected P-deficiency or P-limitation on the basis of Redfield N:P ratios in Daya Bay.
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Affiliation(s)
- Xingyu Song
- Key Laboratory of Tropical Marine Bio-resources and Ecology & Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 164, Xingangxi Road, Guangdong, 510301, Guangzhou, China
| | - Meiting Tan
- Key Laboratory of Tropical Marine Bio-resources and Ecology & Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 164, Xingangxi Road, Guangdong, 510301, Guangzhou, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Ge Xu
- Institute of Marine Science and Technology, Shandong University, Qingdao, 266237, Shandong, China
| | - Xinying Su
- Key Laboratory of Tropical Marine Bio-resources and Ecology & Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 164, Xingangxi Road, Guangdong, 510301, Guangzhou, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Jihua Liu
- Institute of Marine Science and Technology, Shandong University, Qingdao, 266237, Shandong, China
| | - Gaungyan Ni
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, 510160, Guangzhou, China
| | - Yao Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology & Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 164, Xingangxi Road, Guangdong, 510301, Guangzhou, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Yehui Tan
- Key Laboratory of Tropical Marine Bio-resources and Ecology & Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 164, Xingangxi Road, Guangdong, 510301, Guangzhou, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Liangmin Huang
- Key Laboratory of Tropical Marine Bio-resources and Ecology & Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 164, Xingangxi Road, Guangdong, 510301, Guangzhou, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Pingping Shen
- Key Laboratory of Tropical Marine Bio-resources and Ecology & Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 164, Xingangxi Road, Guangdong, 510301, Guangzhou, China.
| | - Gang Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology & Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 164, Xingangxi Road, Guangdong, 510301, Guangzhou, China.
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17
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Vopel K, Del-Río C, Pilditch CA. Effects of CO 2 enrichment on benthic primary production and inorganic nitrogen fluxes in two coastal sediments. Sci Rep 2018; 8:1035. [PMID: 29348554 PMCID: PMC5773597 DOI: 10.1038/s41598-017-19051-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 12/21/2017] [Indexed: 11/26/2022] Open
Abstract
Ocean acidification may alter the cycling of nitrogen in coastal sediment and so the sediment-seawater nitrogen flux, an important driver of pelagic productivity. To investigate how this perturbation affects the fluxes of NOX- (nitrite/nitrate), NH4+ and O2, we incubated estuarine sand and subtidal silt in recirculating seawater with a CO2-adjusted pH of 8.1 and 7.9. During a 41-day incubation, the seawater kept at pH 8.1 lost 97% of its NOX- content but the seawater kept at pH 7.9 lost only 18%. Excess CO2 increased benthic photosynthesis. In the silt, this was accompanied by a reversal of the initial NOX- efflux into influx. The estuarine sand sustained its initial NOX- influx but, by the end of the incubation, released more NH4+ at pH 7.9 than at pH 8.1. We hypothesise that these effects share a common cause; excess CO2 increased the growth of benthic microalgae and so nutrient competition with ammonia oxidising bacteria (AOB). In the silt, diatoms likely outcompeted AOB for NH4+ and photosynthesis increased the dark/light fluctuations in the pore water oxygenation inhibiting nitrification and coupled nitrification/denitrification. If this is correct, then excess CO2 may lead to retention of inorganic nitrogen adding to the pressures of increasing coastal eutrophication.
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Affiliation(s)
- Kay Vopel
- School of Science, Auckland University of Technology, Private Bag, 92006, Auckland, New Zealand.
| | - Cintya Del-Río
- School of Science, Auckland University of Technology, Private Bag, 92006, Auckland, New Zealand
| | - Conrad A Pilditch
- School of Science, University of Waikato, Private Bag, 3105, Hamilton, New Zealand
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18
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Stoichiometric Network Analysis of Cyanobacterial Acclimation to Photosynthesis-Associated Stresses Identifies Heterotrophic Niches. Processes (Basel) 2017. [DOI: 10.3390/pr5020032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Li G, Talmy D, Campbell DA. Diatom growth responses to photoperiod and light are predictable from diel reductant generation. JOURNAL OF PHYCOLOGY 2017; 53:95-107. [PMID: 27754547 PMCID: PMC5363399 DOI: 10.1111/jpy.12483] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 09/13/2016] [Indexed: 05/11/2023]
Abstract
Light drives phytoplankton productivity, so phytoplankton must exploit variable intensities and durations of light exposure, depending upon season, latitude, and depth. We analyzed the growth, photophysiology and composition of small, Thalassiosira pseudonana, and large, Thalassiosira punctigera, centric diatoms from temperate, coastal marine habitats, responding to a matrix of photoperiods and growth light intensities. T. pseudonana showed fastest growth rates under long photoperiods and low to moderate light intensities, while the larger T. punctigera showed fastest growth rates under short photoperiods and higher light intensities. Photosystem II function and content responded primarily to instantaneous growth light intensities during the photoperiod, while diel carbon fixation and RUBISCO content responded more to photoperiod duration than to instantaneous light intensity. Changing photoperiods caused species-specific changes in the responses of photochemical yield (e- /photon) to growth light intensity. These photophysiological variables showed complex responses to photoperiod and to growth light intensity. Growth rate also showed complex responses to photoperiod and growth light intensity. But these complex responses resolved into a close relation between growth rate and the cumulative daily generation of reductant, across the matrix of photoperiods and light intensities.
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Affiliation(s)
- Gang Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - David Talmy
- Department of Earth, Atmosphere and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts, 02139, USA
| | - Douglas A Campbell
- Department of Biology, Mount Allison University, 63B York St., Sackville, New Brunswick, Canada
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Ni G, Zimbalatti G, Murphy CD, Barnett AB, Arsenault CM, Li G, Cockshutt AM, Campbell DA. Arctic Micromonas uses protein pools and non-photochemical quenching to cope with temperature restrictions on Photosystem II protein turnover. PHOTOSYNTHESIS RESEARCH 2017; 131:203-220. [PMID: 27639727 PMCID: PMC5247552 DOI: 10.1007/s11120-016-0310-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/08/2016] [Indexed: 05/12/2023]
Abstract
Micromonas strains of small prasinophyte green algae are found throughout the world's oceans, exploiting widely different niches. We grew arctic and temperate strains of Micromonas and compared their susceptibilities to photoinactivation of Photosystem II, their counteracting Photosystem II repair capacities, their Photosystem II content, and their induction and relaxation of non-photochemical quenching. In the arctic strain Micromonas NCMA 2099, the cellular content of active Photosystem II represents only about 50 % of total Photosystem II protein, as a slow rate constant for clearance of PsbA protein limits instantaneous repair. In contrast, the temperate strain NCMA 1646 shows a faster clearance of PsbA protein which allows it to maintain active Photosystem II content equivalent to total Photosystem II protein. Under growth at 2 °C, the arctic Micromonas maintains a constitutive induction of xanthophyll deepoxidation, shown by second-derivative whole-cell spectra, which supports strong induction of non-photochemical quenching under low to moderate light, even if xanthophyll cycling is blocked. This non-photochemical quenching, however, relaxes during subsequent darkness with kinetics nearly comparable to the temperate Micromonas NCMA 1646, thereby limiting the opportunity cost of sustained downregulation of PSII function after a decrease in light.
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Affiliation(s)
- Guangyan Ni
- Department of Chemistry & Biochemistry, Mount Allison University, 63B York St., Sackville, NB, E4L3M7, Canada
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, CAS, Guangzhou, 510160, China
| | - Gabrielle Zimbalatti
- Department of Chemistry & Biochemistry, Mount Allison University, 63B York St., Sackville, NB, E4L3M7, Canada
| | - Cole D Murphy
- Department of Chemistry & Biochemistry, Mount Allison University, 63B York St., Sackville, NB, E4L3M7, Canada
| | | | - Christopher M Arsenault
- Department of Chemistry & Biochemistry, Mount Allison University, 63B York St., Sackville, NB, E4L3M7, Canada
| | - Gang Li
- Department of Chemistry & Biochemistry, Mount Allison University, 63B York St., Sackville, NB, E4L3M7, Canada
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, CAS, Guangzhou, 510301, China
| | - Amanda M Cockshutt
- Department of Chemistry & Biochemistry, Mount Allison University, 63B York St., Sackville, NB, E4L3M7, Canada
| | - Douglas A Campbell
- Department of Chemistry & Biochemistry, Mount Allison University, 63B York St., Sackville, NB, E4L3M7, Canada.
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Murphy CD, Roodvoets MS, Austen EJ, Dolan A, Barnett A, Campbell DA. Photoinactivation of Photosystem II in Prochlorococcus and Synechococcus. PLoS One 2017; 12:e0168991. [PMID: 28129341 PMCID: PMC5271679 DOI: 10.1371/journal.pone.0168991] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 12/10/2016] [Indexed: 01/15/2023] Open
Abstract
The marine picocyanobacteria Synechococcus and Prochlorococcus numerically dominate open ocean phytoplankton. Although evolutionarily related they are ecologically distinct, with different strategies to harvest, manage and exploit light. We grew representative strains of Synechococcus and Prochlorococcus and tracked their susceptibility to photoinactivation of Photosystem II under a range of light levels. As expected blue light provoked more rapid photoinactivation than did an equivalent level of red light. The previous growth light level altered the susceptibility of Synechococcus, but not Prochlorococcus, to this photoinactivation. We resolved a simple linear pattern when we expressed the yield of photoinactivation on the basis of photons delivered to Photosystem II photochemistry, plotted versus excitation pressure upon Photosystem II, the balance between excitation and downstream metabolism. A high excitation pressure increases the generation of reactive oxygen species, and thus increases the yield of photoinactivation of Photosystem II. Blue photons, however, retained a higher baseline photoinactivation across a wide range of excitation pressures. Our experiments thus uncovered the relative influences of the direct photoinactivation of Photosystem II by blue photons which dominates under low to moderate blue light, and photoinactivation as a side effect of reactive oxygen species which dominates under higher excitation pressure. Synechococcus enjoyed a positive metabolic return upon the repair or the synthesis of a Photosystem II, across the range of light levels we tested. In contrast Prochlorococcus only enjoyed a positive return upon synthesis of a Photosystem II up to 400 μmol photons m-2 s-1. These differential cost-benefits probably underlie the distinct photoacclimation strategies of the species.
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Affiliation(s)
- Cole D. Murphy
- Biochemistry and Chemistry, Mount Allison University, Sackville, New Brunswick, Canada
| | - Mitchell S. Roodvoets
- Biochemistry and Chemistry, Mount Allison University, Sackville, New Brunswick, Canada
| | - Emily J. Austen
- Biology, Mount Allison University, Sackville, New Brunswick, Canada
| | - Allison Dolan
- Biology, Mount Allison University, Sackville, New Brunswick, Canada
| | - Audrey Barnett
- Michigan Technological University, Houghton, Michigan, United States of America
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Boatman TG, Lawson T, Geider RJ. A Key Marine Diazotroph in a Changing Ocean: The Interacting Effects of Temperature, CO2 and Light on the Growth of Trichodesmium erythraeum IMS101. PLoS One 2017; 12:e0168796. [PMID: 28081236 PMCID: PMC5230749 DOI: 10.1371/journal.pone.0168796] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Accepted: 12/06/2016] [Indexed: 11/18/2022] Open
Abstract
Trichodesmium is a globally important marine diazotroph that accounts for approximately 60 - 80% of marine biological N2 fixation and as such plays a key role in marine N and C cycles. We undertook a comprehensive assessment of how the growth rate of Trichodesmium erythraeum IMS101 was directly affected by the combined interactions of temperature, pCO2 and light intensity. Our key findings were: low pCO2 affected the lower temperature tolerance limit (Tmin) but had no effect on the optimum temperature (Topt) at which growth was maximal or the maximum temperature tolerance limit (Tmax); low pCO2 had a greater effect on the thermal niche width than low-light; the effect of pCO2 on growth rate was more pronounced at suboptimal temperatures than at supraoptimal temperatures; temperature and light had a stronger effect on the photosynthetic efficiency (Fv/Fm) than did CO2; and at Topt, the maximum growth rate increased with increasing CO2, but the initial slope of the growth-irradiance curve was not affected by CO2. In the context of environmental change, our results suggest that the (i) nutrient replete growth rate of Trichodesmium IMS101 would have been severely limited by low pCO2 at the last glacial maximum (LGM), (ii) future increases in pCO2 will increase growth rates in areas where temperature ranges between Tmin to Topt, but will have negligible effect at temperatures between Topt and Tmax, (iii) areal increase of warm surface waters (> 18°C) has allowed the geographic range to increase significantly from the LGM to present and that the range will continue to expand to higher latitudes with continued warming, but (iv) continued global warming may exclude Trichodesmium spp. from some tropical regions by 2100 where temperature exceeds Topt.
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Affiliation(s)
- Tobias G. Boatman
- School of Biological Sciences, University of Essex, Colchester, United Kingdom
| | - Tracy Lawson
- School of Biological Sciences, University of Essex, Colchester, United Kingdom
| | - Richard J. Geider
- School of Biological Sciences, University of Essex, Colchester, United Kingdom
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Li G, Campbell DA. Interactive effects of nitrogen and light on growth rates and RUBISCO content of small and large centric diatoms. PHOTOSYNTHESIS RESEARCH 2017; 131:93-103. [PMID: 27566625 PMCID: PMC5167766 DOI: 10.1007/s11120-016-0301-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/17/2016] [Indexed: 05/31/2023]
Abstract
Among marine phytoplankton groups, diatoms span the widest range of cell size, with resulting effects upon their nitrogen uptake, photosynthesis and growth responses to light. We grew two strains of marine centric diatoms differing by ~4 orders of magnitude in cell biovolume in high (enriched artificial seawater with ~500 µmol L-1 µmol L-1 NO3-) and lower-nitrogen (enriched artificial seawater with <10 µmol L-1 NO3-) media, across a range of growth light levels. Nitrogen and total protein per cell decreased with increasing growth light in both species when grown under the lower-nitrogen media. Cells growing under lower-nitrogen media increased their cellular allocation to RUBISCO and their rate of electron transport away from PSII, for the smaller diatom under low growth light and for the larger diatom across the range of growth lights. The smaller coastal diatom Thalassiosira pseudonana is able to exploit high nitrogen in growth media by up-regulating growth rate, but the same high-nitrogen growth media inhibits growth of the larger diatom species.
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Affiliation(s)
- Gang Li
- Biology Department, Mount Allison University, Sackville, NB, E4L 1G7, Canada
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, CAS, Guangzhou, 510301, China
| | - Douglas A Campbell
- Biology Department, Mount Allison University, Sackville, NB, E4L 1G7, Canada.
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24
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Thrane J, Hessen DO, Andersen T. The impact of irradiance on optimal and cellular nitrogen to phosphorus ratios in phytoplankton. Ecol Lett 2016; 19:880-8. [DOI: 10.1111/ele.12623] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 04/20/2016] [Accepted: 04/30/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Jan‐Erik Thrane
- Section for aquatic biology and toxicology (AQUA) Department of Biosciences University of Oslo P.O. Box 1066, Blindern 0316 Oslo Norway
| | - Dag O. Hessen
- Section for aquatic biology and toxicology (AQUA) Department of Biosciences University of Oslo P.O. Box 1066, Blindern 0316 Oslo Norway
| | - Tom Andersen
- Section for aquatic biology and toxicology (AQUA) Department of Biosciences University of Oslo P.O. Box 1066, Blindern 0316 Oslo Norway
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