The effect of nitrate and phosphate availability on Emiliania huxleyi (NZEH) physiology under different CO2 scenarios
نویسندگان
چکیده
Growth and calcification of the marine coccolithophorid Emiliania huxleyi is affected by ocean acidification and macronutrients limitation and its response varies between strains. Here we investigated the physiological performance of a highly calcified E. huxleyi strain, NZEH, in a multiparametric experiment. Cells were exposed to different CO2 levels (ranging from 250 to 1314 μatm) under three nutrient conditions [nutrient replete (R), nitrate limited (-N), and phosphate limited (-P)]. We focused on calcite and organic carbon quotas and on nitrate and phosphate utilization by analyzing the activity of nitrate reductase (NRase) and alkaline phosphatase (APase), respectively. Particulate inorganic (PIC) and organic (POC) carbon quotas increased with increasing CO2 under R conditions but a different pattern was observed under nutrient limitation. The PIC:POC ratio decreased with increasing CO2 in nutrient limited cultures. Coccolith length increased with CO2 under all nutrient conditions but the coccosphere volume varied depending on the nutrient treatment. Maximum APase activity was found at 561 μatm of CO2 (pH 7.92) in -P cultures and in R conditions, NRase activity increased linearly with CO2. These results suggest that E. huxleyi's competitive ability for nutrient uptake might be altered in future high-CO2 oceans. The combined dataset will be useful in model parameterizations of the carbon cycle and ocean acidification.
منابع مشابه
Responses of the Emiliania huxleyi Proteome to Ocean Acidification
Ocean acidification due to rising atmospheric CO2 is expected to affect the physiology of important calcifying marine organisms, but the nature and magnitude of change is yet to be established. In coccolithophores, different species and strains display varying calcification responses to ocean acidification, but the underlying biochemical properties remain unknown. We employed an approach combin...
متن کاملCarbon and nitrogen fluxes in the marine coccolithophore Emiliania huxleyi grown under different nitrate concentrations
a r t i c l e i n f o Information on interaction of C and N at the cellular level is lacking for ecologically relevant phytoplankton species. We examined the effects of NO 3-availability on C and N fluxes in the widely distributed marine coccolithophore Emiliania huxleyi. Cells were cultured at replete (∼280 μM) and ambient (∼10 μM) NO 3-, the latter representing a typical surface water nitrate...
متن کاملInteractive comment on “Influence of CO2 and nitrogen limitation on the coccolith volume of Emiliania huxleyi (Haptophyta)” by M. N. Müller et al
The sensitivity of calcite producing plankton to pCO2 is an important topic within the current debate over the fate of oceanic carbonate production in a high CO2 and warming ocean. Müller et al. present results from a series of culture experiments of a strain of Emiliania huxleyi under different pCO2 levels and conditions of nitrogen availability (N-, N+). The focus of this manuscript is on cha...
متن کاملCharacterization of a nitrogen-regulated protein identified by cell surface biotinylation of a marine phytoplankton.
The biotinylating reagent succinimidyl 6-(biotinamido)hexanoate was used to label the cell surfaces of the cosmopolitan, marine, eukaryotic microorganism Emiliania huxleyi under different growth conditions. Proteins characteristic of different nutrient conditions could be identified. In particular, a nitrogen-regulated protein, nrp1, has an 82-kDa subunit that is present under nitrogen limitati...
متن کاملInteractive comment on “Influence of CO2 and nitrogen limitation on the coccolith volume of Emiliania huxleyi (Haptophyta)” by M. N. Müller et al
The sensitivity of calcite producing plankton to pCO2 is an important topic within the current debate over the fate of oceanic carbonate production in a high CO2 and warming ocean. Müller et al. present results from a series of culture experiments of a strain of Emiliania huxleyi under different pCO2 levels and conditions of nitrogen availability (N-, N+). The focus of this manuscript is on cha...
متن کامل