Seawater carbonate chemistry and nitrogen fixation by phosphorus-limited Trichodesmium

• Main Authors: Zhang, Futing, Wen, Zuozhu, Wang, Shanlin, Tang, Weiyi, Luo, Yawei, Kranz, Sven A, Hong, Haizheng, Shi, Dalin
• Format: Dataset
• Language: English
• Published: PANGAEA 2023
• Subjects: Adenosine 5-Triphosphate; per cell; Alkaline phosphatase; para-Nitrophenylphosphate per cell; Alkalinity; total; Aragonite saturation state; Bacteria; Bicarbonate ion; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (<20 L); Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; organic; particulate/Phosphorus; particulate ratio; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cell; length; standard deviation; width; Cell density; Chlorophyll a; Chlorophyll a per cell; Cyanobacteria; Day of experiment; Entire community; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gene copies; Gene expression; Gene expression (incl. proteomics); Glutamate per cell; Growth/Morphology; Laboratory experiment; Laboratory strains; LATITUDE; Lipids per cell; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.957342; https://doi.org/10.1594/PANGAEA.957342

Growth of the prominent nitrogen-fixing cyanobacterium Trichodesmium is often limited by phosphorus availability in the ocean. How nitrogen fixation by phosphorus-limited Trichodesmium may respond to ocean acidification remains poorly understood. Here, we use phosphate-limited chemostat experiments to show that acidification enhanced phosphorus demands and decreased phosphorus-specific nitrogen fixation rates in Trichodesmium. The increased phosphorus requirements were attributed primarily to elevated cellular polyphosphate contents, likely for maintaining cytosolic pH homeostasis in response to acidification. Alongside the accumulation of polyphosphate, decreased NADP(H):NAD(H) ratios and impaired chlorophyll synthesis and energy production were observed under acidified conditions. Consequently, the negative effects of acidification were amplified compared to those demonstrated previously under phosphorus sufficiency. Estimating the potential implications of this finding, using outputs from the Community Earth System Model, predicts that acidification and dissolved inorganic and organic phosphorus stress could synergistically cause an appreciable decrease in global Trichodesmium nitrogen fixation by 2100.