Publication Date:
2024-05-27
Description:
Calcifying haptophytes (coccolithophores) sequester carbon in the form of organic and inorganic cellular components (coccoliths). We examined the effect of phosphorus (P) limitation and heat stress on particulate organic and inorganic carbon (calcite) production in the coccolithophore Emiliania huxleyi. Both environmental stressors are related to rising CO2 levels and affect carbon production in marine microalgae, which in turn impacts biogeochemical cycling. Using semi-continuous cultures, we show that P limitation and heat stress decrease the calcification rate in E. huxleyi. However, using batch cultures, we show that different culturing approaches (batch versus semi-continuous) induce different physiologies. This affects the ratio of particulate inorganic (PIC) to organic carbon (POC) and complicates general predictions on the effect of P limitation on the PIC/POC ratio. We found heat stress to increase P requirements in E. huxleyi, possibly leading to lower standing stocks in a warmer ocean, especially if this is linked to lower nutrient input. In summary, the predicted rise in global temperature and resulting decrease in nutrient availability may decrease CO2 sequestration by E. huxleyi through lower overall carbon production. Additionally, the export of carbon may be diminished by a decrease in calcification and a weaker coccolith ballasting effect.
Keywords:
Abundance per volume; Alkalinity, total; Carbon, organic, particulate, per cell; Carbon, total, particulate, per cell; Cell, diameter; Cell, diameter, standard deviation; Coccoliths; Coccoliths, incomplete; Coccoliths, malformed; Coccoliths per coccosphere; Coccoliths per coccosphere, standard deviation; Equivalent spherical diameter; Experiment; Growth rate; Number of cells; Oslo_Fjord; pH; Phosphate; Phosphorus, organic, particulate, per cell; Replicate; Species; Treatment: nutrients; Treatment: temperature
Type:
Dataset
Format:
text/tab-separated-values, 2012 data points
