کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4553845 | 1627974 | 2006 | 24 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Trophic structure and pathways of biogenic carbon flow in the eastern North Water Polynya
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
زمین شناسی
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چکیده انگلیسی
In the eastern North Water, most of the estimated annual new and net production of carbon (C) occurred during the main diatom bloom in 1998. During the bloom, at least 30% of total and new phytoplankton production occurred as dissolved organic carbon (DOC) and was unavailable for short-term assimilation into the herbivorous food web or sinking export. Based on particle interceptor traps and 234Th deficits, 27% of the particulate primary production (PP) sank out of the upper 50Â m, with only 7% and 1% of PP reaching the benthos at shallow (â200Â m) and deep (â500Â m) sites, respectively. Mass balance calculations and grazing estimates agree that â79% of PP was ingested by pelagic consumers between April and July. During this period, the vertical flux of biogenic silica (BioSi) at 50Â m was equivalent to the total BioSi produced, indicating that all of the diatom production was removed from the euphotic zone as intact cells (direct sinking) or empty frustules (grazing or lysis). The estimated flux of empty frustules was consistent with rates of herbivory by the large, dominant copepods and appendicularians during incubations. Since the carbon demand of the dominant planktivorous bird, Alle alle, amounted to â2% of the biomass synthesized by its main prey, the large copepod Calanus hyperboreus, most of the secondary carbon production was available to pelagic carnivores. Stable isotopes indicated that the biomass of predatory amphipods, polar cod and marine mammals was derived from these herbivores, but corresponding carbon fluxes were not quantified. Our analysis shows that a large fraction of PP in the eastern North Water was ingested by consumers in the upper 50Â m, leading to substantial carbon respiration and DOC accumulation in surface waters. An increasingly early and prolonged opening of the Artic Ocean is likely to promote the productivity of the herbivorous food web, but not the short-term efficiency of the particulate, biological CO2 pump.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Progress in Oceanography - Volume 71, Issues 2â4, OctoberâDecember 2006, Pages 402-425
Journal: Progress in Oceanography - Volume 71, Issues 2â4, OctoberâDecember 2006, Pages 402-425
نویسندگان
Jean-Ãric Tremblay, Hiroshi Hattori, Christine Michel, Marc Ringuette, Zhi-Ping Mei, Connie Lovejoy, Louis Fortier, Keith A. Hobson, David Amiel, Kirk Cochran,