Shaping of bacterial community composition and diversity by phytoplankton and salinity in the Delaware Estuary, USA

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 78:93-106 (2017) - DOI: https://doi.org/10.3354/ame01805 Shaping of bacterial community composition and diversity by phytoplankton and salinity in the Delaware Estuary, USA David L. Kirchman1,*, Matthew T. Cottrel1, Giacomo R. DiTullio2 1School of Marine Science and Policy, University of Delaware, Lewes, DE 19958, USA 2College of Charleston, Hollings Marine Laboratory, Charleston, SC 29412, USA *Corresponding author: kirchman@udel.edu ABSTRACT: Our understanding of the impact of phytoplankton on bacterial communities is largely based on studies showing that a few bacteria have interactions with the phytoplankton class, which is often diatoms, dominating phytoplankton communities. To determine the effect of the complete phytoplankton community on the entire bacterial community, we used tag pyrosequences of the 16S rRNA gene and phytoplankton pigments measured by high performance liquid chromatography along with Chemtax analyses to examine bacterial and phytoplankton communities along the salinity gradient of the Delaware Estuary, USA, in August and November of 3 years (2011-2013). Salinity had a large effect on the composition, taxon richness, and evenness of bacterial communities in the estuary, but so too did the composition and biomass of the phytoplankton community. Phytoplankton classes had a larger effect in shaping the composition of bacterial communities than did total chlorophyll a. Although diatoms and cryptophytes dominated the phytoplankton communities in both August and November, less common phytoplankton classes, such as dinoflagellates, haptophytes, and prasinophytes, had more significant relationships with the entire bacterial community and with individual bacterial taxa. In contrast, the 2 most abundant bacterial subclades in the estuary, SAR11 IIIa and SAR 11 IIIb, had few significant relationships with chlorophyll a or with phytoplankton classes. These data on bacterial and phytoplankton community composition help to explain the weak coupling between bacteria and phytoplankton communities often observed in estuarine and other aquatic systems. KEY WORDS: 16S rRNA · Chemtax · SAR11 · Diatoms · Bacteroidetes · Planctomycetes Full text in pdf format Supplementary material PreviousNextCite this article as: Kirchman DL, Cottrel MT, DiTullio GR (2017) Shaping of bacterial community composition and diversity by phytoplankton and salinity in the Delaware Estuary, USA. Aquat Microb Ecol 78:93-106. https://doi.org/10.3354/ame01805 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 78, No. 2. Online publication date: January 12, 2017 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2017 Inter-Research.