Carbon metabolism in a humic lake: Pool sires and cycling through zooplankton
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In this article, the authors characterized the major carbon pathways in a humic lake, determined carbon pool sizes and main pathways by long-term tracer studies in enclosures, and found that dissolved organic carbon (DOC) was by far the largest pool and constituted 80-85% of total carbon.Abstract:
To characterize the major carbon pathways in a humic lake, we determined carbon pool sizes and main pathways by long-term tracer studies in enclosures. Dissolved organic carbon (DOC) was by far the largest pool and constituted 80–85% of total carbon. In the water column particulate organic carbon was partitioned between detritus, zooplankton, bacteria, and phytoplankton at ratios of 22 : 4 : 3 : 1. Phytoplankton and bacterioplankton production averaged 24 and 32 µg C liter−1 d−1, while crustacean zooplankton production was very low (<5 µg C liter−1 d−1) during the experiment. Total pelagic community respiration was high, giving a net CO2 flux to the atmosphere of 44 µg C liter−1 d−1, while losses by sedimentation were negligible.
Most of the particulate carbon available for zooplankton was highly recycled detritus of low nutritional value. The loop of ingestion and defecation of detrital particles was a major carbon pathway, giving detrital particles a turnover rate of 0.39 d−1. Detritus was found to support 46–82% of body carbon in the surveyed species, with Acanthodiaptomus as the upper extreme. Bacterial carbon accounted for 11–42% of body carbon and phytoplankton for 6–19% in the surveyed species.read more
Citations
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TL;DR: In the last decade, a new pattern of Hg pollution has been discerned, mostly in Scandinavia and North America, mostly due to more widespread air pollution and long-range transport of pollutants.
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Book ChapterDOI
The influence of humic substances on lacustrine planktonic food chains.
TL;DR: Humic substances (HS) might influence planktonic food chains in lakes in two ways: 1) by altering the physical or chemical environment and thus modifying autotrophic primary production and the dependent food chains; 2) by acting as a direct carbon/energy source for food chains.
References
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Book
Organic geochemistry of natural waters
TL;DR: The first part of the book as mentioned in this paper is a general overview of the amount and general nature of dissolved organic carbon in natural waters, and the second part is a summary of the data that has accumulated from many disciplines over the last decade.
Journal ArticleDOI
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J. W. G. Lund,R. A. Vollenweider +1 more
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Sanghoon Lee,Jed A. Fuhrman +1 more
TL;DR: It is concluded that natural marine bacterial biomass and production may be higher than was previously thought and that variations in bacterial size may not reflect variations in biomass per cell.
Journal ArticleDOI
Determination of bacterial number and biomass in the marine environment.
TL;DR: The biomass of gram-negative (LPS containing) bacteria was shown to be related to the LPS content of the samples, and a factor of 6.35 was determined for converting LPS to bacterial carbon.