Publication Date:
2024-03-15
Description:
Diazotrophic cyanobacteria often form extensive summer blooms in the Baltic Sea driving their environment into phosphate limitation. One of the main species is the heterocystous cyanobacterium Nodularia spumigena. N. spumigena exhibits accelerated uptake of phosphate through the release of the exoenzyme alkaline phosphatase that also serves as an indicator of the hydrolysis of dissolved organic phosphorus (DOP). The present study investigated the utilization of DOP and its compounds (e.g. ATP) by N. spumigena during growth under varying CO2 concentrations, in order to estimate potential consequences of ocean acidification on the cell's supply with phosphorus. Cell growth, phosphorus pool fractions, and four DOP-compounds (ATP, DNA, RNA, and phospholipids) were determined in three set-ups with different CO2 concentrations (341, 399, and 508 µatm) during a 15-day batch experiment. The results showed rapid depletion of dissolved inorganic phosphorus (DIP) in all pCO2 treatments while DOP utilization increased with elevated pCO2, in parallel with the growth stimulation of N. spumigena. During the growth phase, DOP uptake was enhanced by a factor of 1.32 at 399 µatm and of 2.25 at 508 µatm compared to the lowest pCO2 concentration. Among the measured DOP compounds, none was found to accumulate preferentially during the incubation or in response to a specific pCO2 treatment. However, at the beginning 61.9 ± 4.3% of the DOP were not characterized but comprised the most highly utilized fraction. This is demonstrated by the decrement of this fraction to 27.4 ± 9.9% of total DOP during the growth phase, especially in response to the medium and high pCO2 treatment. Our results indicate a stimulated growth of diazotrophic cyanobacteria at increasing CO2 concentrations that is accompanied by increasing utilization of DOP as an alternative P source.
Keywords:
Alkalinity, total; Alkalinity, total, standard deviation; Aragonite saturation state; Bacteria; Baltic Sea; Bicarbonate ion; Bottles or small containers/Aquaria (〈20 L); Calcite saturation state; Calculated; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chlorophyll a; Chlorophyll a, standard deviation; Colorimetric; Cyanobacteria; DATE/TIME; Fluorometric; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Incubation duration; Laboratory experiment; Laboratory strains; Liquid scintillation; Nodularia spumigena; OA-ICC; Ocean Acidification International Coordination Centre; Other metabolic rates; Partial pressure of carbon dioxide, standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Particulate organic phosphorus, standard deviation; Pelagos; pH; pH, standard deviation; Phosphate, organic, dissolved, standard deviation; Phosphorus, adenosine triphosphate, dissolved; Phosphorus, adenosine triphosphate, dissolved, standard deviation; Phosphorus, deoxyribonucleic acid, dissolved; Phosphorus, deoxyribonucleic acid, dissolved, standard deviation; Phosphorus, inorganic, dissolved; Phosphorus, inorganic, dissolved, standard deviation; Phosphorus, organic, dissolved; Phosphorus, organic, particulate; Phosphorus, phospholipid, dissolved; Phosphorus, phospholipid, dissolved, standard deviation; Phosphorus, ribonucleic acid, dissolved; Phosphorus, ribonucleic acid, dissolved, standard deviation; Phytoplankton; Potentiometric; Proportion, phosphate with 33 Phosphorus; Proportion, phosphate with 33 Phosphorus, standard deviation; Salinity; Single species; Sirius Luminometer; Species; Spectrophotometric; Temperature, water; Treatment
Type:
Dataset
Format:
text/tab-separated-values, 924 data points
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