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Impact of temperature, CO2, and iron on nutrient uptake by a late-season microbial community from the Ross Sea, Antarctica

TitleImpact of temperature, CO2, and iron on nutrient uptake by a late-season microbial community from the Ross Sea, Antarctica
Publication TypeJournal Article
Year of Publication2019
AuthorsSpackeen J.L, Sipler R.E, Bertrand E.M, Xu K., McQuaid J.B, Walworth N.G, Hutchins D.A, Allen A.E, Bronk D.A
JournalAquatic Microbial Ecology
Volume82
Pagination145-159
Date Published2018/11
Type of ArticleArticle
ISBN Number0948-3055
Accession NumberWOS:000454321300003
Keywordsacidification; climate-change; co2; community; concentrating mechanisms; continuous-culture system; DIC; Environmental Sciences & Ecology; growth; inorganic carbon uptake; Iron; Marine & Freshwater Biology; marine-phytoplankton; microbiology; nitrate; nitrogen uptake; ocean; phytoplankton; ross sea; temperature; uptake
Abstract

The Southern Ocean is rapidly changing as a result of rising sea surface temperatures, elevated CO2 concentrations, and modifications to iron sources and sinks. The Southern Ocean has seasonally high rates of primary production, making it critical to determine how changes will impact biogeochemical rate processes in this important sink for CO2. During the austral summer, we measured nitrogen and carbon uptake rates by a late-season Ross Sea microbial community under different potential climate change conditions. A natural microbial assemblage was collected from the ice edge, and grown using a semi-continuous culturing followed by a continuous culturing 'ecostat' approach. The individual and combined impacts of temperature elevation and iron addition were tested during both approaches, and CO2 level was also manipulated during the continuous experiment. Nutrient concentrations and biomass parameters were measured throughout both experiments. During the continuous experiment we also measured uptake rates of nitrate (NO3-) and dissolved inorganic carbon (DIC) by 2 size classes (0.7-5.0 and >5.0 mu m) of microorganisms. Of the parameters tested, temperature elevation had the largest impact, significantly increasing NO3- and DIC uptake rates by larger microorganisms. Iron addition was also important; however, the magnitude of its impact was greater when temperature was also changed. These results indicate that NO3- and DIC uptake rates may increase as sea surface warming occurs in the Southern Ocean, and thus have important implications for estimating new production and potential carbon uptake and eventual export to the deep sea.

DOI10.3354/ame01886
Short TitleAquat. Microb. Ecol.
Student Publication: 
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