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Production and food...
Production and food web interactions of Arctic freshwater plankton and responses to increased DOC
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Hessen, Dag O. (author)
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- Blomqvist, Peter (author)
- Uppsala universitet,Limnologi
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Dahl-Hansen, Geir (author)
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- Drakare, Stina (author)
- Uppsala universitet,Limnologi
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- Lindström, Eva S. (author)
- Uppsala universitet,Limnologi
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(creator_code:org_t)
- Schweizerbart, 2004
- 2004
- English.
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In: Archiv für Hydrobiologie. - : Schweizerbart. - 0003-9136. ; 159:3, s. 289-307
- Related links:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Subject headings
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- A gradient of dissolved organic carbon (DOC) was added to enclosures in a high Arctic lake (Svalbard, 79 N). The aim was to simulate the effect of increased concentrations of DOC that will be a predicted effect of increased temperature and precipitation. The study aimed to provide information on the overall effects of such increased levels of DOC on the pelagic food-web, as well as the increased attenuation of UV-radiation (UV-R) caused by increased DOC. The biomass development of phytoplankton, heterotrophic bacteria and ciliates from 15. July (shortly after ice-off) to 8. August revealed a consistent pattern across all enclosures. Initial phytoplankton biomass decreased from maxima around 600g Cl-1 towards 50g Cl-1 by the end of July. Similarly, ciliate biomass decreased from ~100 to 5g Cl-1, while heterotrophic bacteria decreased from initially 280 g Cl-1 to biomasses near 100 g Cl-1. Over the same period, zooplankton biomass (almost a monoculture of Daphnia tenebrosa) increased from <40 to some 170g Cl-1. These patterns were reflected also in decreasing absolute production of bacteria and phytoplankton, while production:biomass ratio remained fairly constant. In general, the study demonstrated a very dynamic system over the brief ice-free season, where Daphnia grazing had a strong impact on the unicellular biota. Additions of DOC initially stimulated planktonic production, yet this effect was soon overruled by Daphnia grazing. This stimulating effect could be a result both of increased UV-R attenuation and some growth stimulating effect. Since no corresponding stimulating effect was observed in the bag shielded with Mylar filter to screen off UV-B, the latter cause seems most likely.
Subject headings
- NATURVETENSKAP -- Biologi -- Ekologi (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences -- Ecology (hsv//eng)
Keyword
- Arctic
- dissolved carbon
- UV-radiation
- plankton
- Daphnia
- trophic interactions
Publication and Content Type
- ref (subject category)
- art (subject category)
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