title: Elevated temperature increases carbon and nitrogen fluxes between phytoplankton and heterotrophic bacteria through physical attachment.
abstract: Quantifying the contribution of marine microorganisms to carbon and nitrogen cycles and their response to predicted ocean warming is one of the main challenges of microbial oceanography. Here we present a single-cell NanoSIMS isotope analysis to quantify C and N uptake by free-living and attached phytoplankton and heterotrophic bacteria, and their response to short-term experimental warming of 4 °C. Elevated temperature increased total C fixation by over 50%, a small but significant fraction of which was transferred to heterotrophs within 12 h. Cell-to-cell attachment doubled the secondary C uptake by heterotrophic bacteria and increased secondary N incorporation by autotrophs by 68%. Warming also increased the abundance of phytoplankton with attached heterotrophs by 80%, and promoted C transfer from phytoplankton to bacteria by 17% and N transfer from bacteria to phytoplankton by 50%. Our results indicate that phytoplankton-bacteria attachment provides an ecological advantage for nutrient incorporation, suggesting a mutualistic relationship that appears to be enhanced by temperature increases.
authors.affiliation: Centro Oceanográfico de Gijón/Xixón, Instituto Español de Oceanografía, Centro Oceanográfico de Gijón/Xixón, Gijón/Xixón, Asturias, Spain.
authors.forename: Nestor
authors.initials: N
authors.lastname: Arandia-Gorostidi
authors.affiliation: Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA, USA.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Weber
authors.affiliation: Centro Oceanográfico de Gijón/Xixón, Instituto Español de Oceanografía, Centro Oceanográfico de Gijón/Xixón, Gijón/Xixón, Asturias, Spain.|AZTI, Sukarrieta, Bizkaia, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Alonso-Sáez
authors.affiliation: Centro Oceanográfico de Gijón/Xixón, Instituto Español de Oceanografía, Centro Oceanográfico de Gijón/Xixón, Gijón/Xixón, Asturias, Spain.|Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
authors.forename: Xosé Anxelu G
authors.initials: XA
authors.lastname: Morán
authors.affiliation: Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA, USA.|Oregon State University, Microbiology Department, Corvallis, OR, USA.
authors.forename: Xavier
authors.initials: X
authors.lastname: Mayali
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism*; D057231:Climate Change; D052836:Heterotrophic Processes; D009584:Nitrogen / Q000378:metabolism*; D058458:Nitrogen Cycle; D010839:Phytoplankton / Q000378:metabolism*; D012623:Seawater / Q000382:microbiology*; D013030:Spain; D013696:Temperature
chemical_list: D002244:Carbon; D009584:Nitrogen