Total and phytoplankton mediated bottom-up control of bacterioplankton change with temperature in NE Atlantic shelf waters
Moran, Xose Anxelu G.
Ducklow, Hugh W.
MetadataShow full item record
KeywordBacterioplankton; Bottom-up control; Temperature; Bacterial biomass; Bacterial activity; Phytoplankton; Coastal waters
The regulation of heterotrophic bacterial growth by resource supply (bottom-up control) was temperature-dependent in our analysis of data obtained during 2006 in the euphotic layer of the southern Bay of Biscay (NE Atlantic) continental shelf. The dataset was split into 2 subgroups using 16°C as the boundary between warm and cool waters based on differences in associated physico-chemical conditions, e.g. inorganic nutrient limitation at higher temperatures. The linear regressions between bacterial biomass (BB) and leucine incorporation rates (LIR) were significantly positive in both temperature regimes, thus indicating similar total bottom-up control, albeit with a slightly higher slope in warm waters (0.33 vs. 0.22). However, the relationship of LIR with phytoplankton biomass (chl a), which is an indicator of bottom-up control that is mediated by phytoplankton, was only significant in waters below 16°C. The analysis of bimonthly variations in the BB-LIR and LIR-chl a correlations indicated that the strength of total bottom-up control significantly increased while the role of phytoplankton in supplying DOM to bacteria diminished with mean temperatures over the 12 to 19°C range, suggesting a seasonal switch in the major source of substrates used by bacteria. We show that the abundance of cells with relatively high nucleic acid content (HNA), which are hypothesized to be the most active ones, was positively associated with bacterial production and specific growth rates in cool but not in warm conditions. These results suggest that HNA bacteria are good predictors of bulk activity and production in temperate ecosystems only when the community relies principally on phytoplankton substrates for growth and metabolism.
Author Posting. © Inter-Research, 2010. This article is posted here by permission of Inter-Research for personal use, not for redistribution. The definitive version was published in Aquatic Microbial Ecology 58 (2010): 229-239, doi:10.3354/ame01374.
Showing items related by title, author, creator and subject.
Depleted dissolved organic carbon and distinct bacterial communities in the water column of a rapid-flushing coral reef ecosystem Nelson, Craig E.; Alldredge, Alice L.; McCliment, Elizabeth A.; Amaral-Zettler, Linda A.; Carlson, Craig A. (2011-01-11)Coral reefs are highly productive ecosystems bathed in unproductive, low-nutrient oceanic waters, where microbially-dominated food webs are supported largely by bacterioplankton recycling of dissolved compounds. Despite ...
Ducklow, Hugh W.; Myers, Kristen M. S.; Erickson, Matthew; Ghiglione, Jean-Francois; Murray, Alison E. (Inter-Research, 2011-09-20)Along the western Antarctic Peninsula, marine bacterioplankton respond to the spring phytoplankton bloom with increases in abundance, production and growth rates, and a seasonal succession in bacterial community composition ...
Microbial biogeography along an estuarine salinity gradient : combined influences of bacterial growth and residence time Crump, Byron C.; Hopkinson, Charles S.; Sogin, Mitchell L.; Hobbie, John E. (American Society for Microbiology, 2004-03)Shifts in bacterioplankton community composition along the salinity gradient of the Parker River estuary and Plum Island Sound, in northeastern Massachusetts, were related to residence time and bacterial community doubling ...