Publication Date:
2022-05-26
Description:
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 60 (2010): 273-287, doi:10.3354/ame01427.
Description:
Previous studies have focused on the role of labile dissolved organic matter (DOM) (defined as turnover time of ~1 d) in supporting heterotrophic bacterial production, but have mostly neglected semilabile DOM (defined as turnover time of ~100 to 1000 d) as a potential substrate for heterotrophic bacterial growth. To test the hypothesis that semilabile DOM supports substantial amounts of heterotrophic bacterial production in the open ocean, we constructed a 1-dimensional epipelagic ecosystem model and applied it to 3 open ocean sites: the Arabian Sea, Equatorial Pacific and Station ALOHA in the North Pacific Subtropical Gyre. The model tracks carbon, nitrogen and phosphorus with flexible stoichiometry. This study used a large number of observations, including measurements of heterotrophic bacterial production rates and standing stocks, and DOM concentration data, to rigorously test and constrain model output. Data assimilation was successfully applied to optimize the model parameters and resulted in simultaneous representation of observed nitrate, phosphate, phytoplankton and zooplankton biomass, primary production, heterotrophic bacterial biomass and production, DOM, and suspended and sinking particulate organic matter. Across the 3 ocean ecosystems examined, the data assimilation suggests semilabile DOM may support 17 to 40% of heterotrophic bacterial carbon demand. In an experiment where bacteria only utilize labile DOM, and with more of the DOM production assigned to labile DOM, the model poorly represented the observations. These results suggest that semilabile DOM may play an important role in sustaining heterotrophic bacterial growth in diverse regions of the open ocean.
Description:
Y.W.L. was supported by fellowships from the Virginia Institute
of Marine Sciences and Marine Biological Laboratory as
well as NSF Grants OPP-0217282 and 0823101 to H.W.D. and
VIMS and MBL, respectively. M.A.M.F.’s participation was
supported in part by a grant from the NASA Ocean Biology
and Biogeochemistry program (NNX07AF70G), S.C.D.’s participation was supported by an NSF grant to the Center
for Microbial Oceanography, Research and Education (CMORE),
NSF EF-0424599, and M.J.C. was supported in part
by NSF grants EF-0424599 (C-MORE) and OCE 0425363.
Keywords:
Heterotrophic bacteria
;
Semilabile dissolved organic matter
;
Marine ecosystem model
;
Data assimilation
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
application/pdf
Permalink
