The Southern Ocean exerts a strong impact on marine biogeochemical cycles and global air‐sea CO 2 fluxes. Over the coming century, large increases in surface ocean levels, combined with increased upper water column temperatures stratification, are expected to diminish uptake. These effects could be significantly modulated by concomitant ‐dependent changes region's biological carbon pump. Here we show that concentrations affect physiology, growth species composition of phytoplankton...

The potential interactive effects of iron (Fe) limitation and Ocean Acidification in the Southern (SO) are largely unknown. Here we present results a long-term incubation experiment investigating combined CO2 Fe availability on natural phytoplankton assemblages from Weddell Sea, Antarctica. Active Chl fluorescence measurements revealed that successfully cultured under both Fe-depleted Fe-enriched conditions. treatments had significant photosynthetic efficiency (Fv/Fm; 0.3 for 0.5...

Despite the fact that ocean acidification is considered to be especially pronounced in Southern Ocean, little known about CO 2 ‐dependent physiological processes and interactions of Antarctic phytoplankton key species. We therefore studied effects partial pressure (P CO2 ) (16.2, 39.5, 101.3 Pa) on growth photosynthetic carbon acquisition bloom‐forming species Chaetoceros debilis, Pseudo‐nitzschia subcurvata, Fragilariopsis kerguelensis, Phaeocystis antarctica. Using membrane‐inlet mass...

Summary There is increasing evidence that different light intensities strongly modulate the effects of ocean acidification ( OA ) on marine phytoplankton. The aim present study was to investigate interactive and dynamic light, mimicking natural mixing regimes. Antarctic diatom C haetoceros debilis grown under two p CO 2 (390 1000 μatm) conditions (constant dynamic), latter yielding same integrated irradiance over day. To characterize between treatments, growth, elemental composition, primary...

Abstract While it has been recently demonstrated that both iron (Fe) and manganese (Mn) control Southern Ocean (SO) plankton biomass, how in particular Mn governs phytoplankton species composition remains yet unclear. This study, for the first time, highlights importance of next to Fe growth two key SO groups at locations Drake Passage (West East). Even though bulk parameter chlorophyll a indicated availability as main driver assemblages, flow cytometric microscopic analysis revealed FeMn...

The effects of pH-induced changes in seawater carbonate chemistry on inorganic carbon (C(i)) acquisition and domoic acid (DA) production were studied two potentially toxic diatom species, Pseudo-nitzschia multiseries Nitzschia navis-varingica, the non-toxic Stellarima stellaris. In vivo activities carbonic anhydrase (CA), photosynthetic O(2) evolution CO(2) HCO(3)(-) uptake rates measured by membrane inlet MS cells acclimated to low (7.9) high pH (8.4 or 8.9). Species-specific differences...

Coccolithophores, especially the abundant, cosmopolitan species Emiliania huxleyi (Lohmann) W. Hay et H. P. Mohler, are one of main driving forces oceanic carbonate pump and contribute significantly to global carbon cycling, due their ability calcify. A recent study indicates that termination diploid blooms by viral infection induces life-cycle transition, speculation has arisen about role haploid, noncalcifying stage in coccolithophore ecology. To explore gene expression patterns both...

In some parts of the Southern Ocean (SO), even though low surface concentrations iron (Fe) and manganese (Mn) indicate FeMn co-limitation, we still lack an understanding on how Mn Fe availability influences SO phytoplankton ecophysiology. Therefore, this study investigated effects limitation alone as well their combination growth, photophysiology particulate organic carbon production bloom-forming Antarctic diatom Chaetoceros debilis. Our results clearly show that photochemical efficiency C....

Various protective and metabolic functions for coccolithophore calcification have been proposed such as providing a means to supply CO 2 photosynthesis. It has also speculated that helps dissipate excess energy under high irradiance, thereby circumventing photoinhibition. To address these questions, cells of calcifying strain Emiliania huxleyi were grown at three irradiances (30, 300, 800 µmol photons m −2 s −1 ) in combination with four calcium (Ca) concentrations (0.1, 1, 2.5, 10 mmol L...

In recent studies the Sr/Ca ratio of coccolithophore calcite was used as a proxy for past growth and calcification rates. Since Sr Ca concentrations in seawater have not remained constant through time, interpretation data from coccolith-dominated sedimentary record requires knowledge about incorporation into coccolith during coccolithogenesis. Here we show that Emiliania huxleyi coccoliths is linearly related to Sr/Ca, meaning exchange coefficient does change with changing Sr/Ca. The this...

The Antarctic Circumpolar Current has a high potential for primary production and carbon sequestration through the biological pump. In current study, two large-scale blooms observed in 2012 during cruise with R.V. Polarstern were investigated respect to phytoplankton standing stocks, productivity nutrient budgets. While net was similar both blooms, chlorophyll –specific photosynthesis more efficient bloom closer island of South Georgia (39 °W, 50 °S) compared open ocean further east (12 51...

Iron availability strongly governs the growth of Southern Ocean phytoplankton. To investigate how iron limitation affects photosynthesis as well uptake carbon and in Antarctic diatom Chaetocerossimplex, a combination chlorophyll fluorescence measurements radiotracer incubations presence absence chemical inhibitors was conducted. C. simplex led to decline rates, photochemical efficiency structural changes photosystem II (PSII), including reorganisation photosynthetic units PSII an increase...

To better understand the impact of ocean acidification ( OA ) and changes in light availability on Southern Ocean phytoplankton physiology, we investigated effects pCO 2 (380 800 µatm) combination with low high irradiance (20 or 50 200 µmol photons m −2 s −1 growth, particulate organic carbon POC fixation photophysiology three ecologically relevant species Chaetoceros debilis , Fragilariopsis kerguelensis Phaeocystis antarctica . Irrespective scenario, neither growth nor per cell was...

Over the last decades, it has been reported that habitat of Southern Ocean (SO) key species Antarctic krill (Euphausia superba) contracted to high latitudes, putatively due reduced winter sea ice coverage, while salps as Salpa thompsoni have extended their dispersal former habitats. To date, potential implications this population shift on biogeochemical cycling limiting micronutrient iron (Fe) and its bioavailability SO phytoplankton never tested. Based uptake fecal pellet (FP)-released Fe...

Photophysiological processes as well uptake characteristics of iron and inorganic carbon were studied in inshore phytoplankton assemblages the Western Antarctic Peninsula (WAP) offshore Drake Passage. Chlorophyll a concentrations primary productivity decreased from in- to waters. The inverse relationship between low maximum quantum yields photochemistry PSII (Fv/Fm) large sizes functional absorption cross sections (σPSII) communities indicated iron-limitation. Congruently, negative...

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 578:35-50 (2017) - DOI: https://doi.org/10.3354/meps12250 Iron sources alter response of Southern Ocean phytoplankton ocean acidification Scarlett Trimborn1,2,*, Tina Brenneis1, Clara J. M. Hoppe1, Luis Laglera3, Louiza Norman4, Juan Santos-Echeandía5, Christian Völkner1, Dieter Wolf-Gladrow1, Christel S....

Abstract Phytoplankton photosynthesis strongly relies on the operation of carbon‐concentrating mechanisms (CCMs) to accumulate CO 2 around their carboxylating enzyme ribulose‐1,5‐bisphosphate carboxylase/oxygenase (RuBisCO). Earlier evolved phytoplankton groups were shown exhibit higher CCM activities compensate for RuBisCO with low specificities. Here, we tested whether earlier also a plasticity. To this end, collected data from literature and applied Bayesian linear meta‐analytic model....

It is largely unknown how rising atmospheric CO2 concentrations and changes in the upper mixed layer depth, with its subsequent effects on light availability will affect phytoplankton physiology Southern Ocean. Linking seasonal variations of to abundances physiological traits key species could aid understand their abilities acclimate predicted future climatic conditions. To investigate combined two ecologically relevant Antarctic diatoms (Fragilariopsis curta Odontella weisflogii) a matrix...

Although iron (Fe) availability primarily sets the rate of phytoplankton growth and primary export production in Southern Ocean, other environmental factors, most significantly light, also affect productivity. As light strongly influences species distribution low Fe-waters, we investigated combined effects increasing (20, 200 500 μmol photons m−2 s−1) conjunction with different Fe (0.4 2 nM Fe) on physiology two ecologically relevant Chaetoceros debilis (Bacillariophyceae) Phaeocystis...

The present study examines how different pCO2 acclimations affect the CO2- and light-dependence of photophysiological processes O2 fluxes in four Southern Ocean (SO) key phytoplankton species. We grew Chaetoceros debilis (Cleve), Pseudo-nitzschia subcurvata (Hasle), Fragilariopsis kerguelensis (O'Meara) Phaeocystis antarctica (Karsten) under low (160 μatm) high (1000 pCO2. fluorescence parameters photosystem II (PSII) were determined by means a induction relaxation system (FIRe). In all...