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Simulated patterns of carbon flow in the pelagic food web of Lake Fryxell, Antarctica: little evidence of top-down control
Citation
McKenna, KC and Moorhead, DL and Roberts, EC and Laybourn-Parry, J, Simulated patterns of carbon flow in the pelagic food web of Lake Fryxell, Antarctica: little evidence of top-down control, Ecological Modelling, 192, (3-4) pp. 457-472. ISSN 0304-3800 (2006) [Refereed Article]
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DOI: doi:10.1016/j.ecolmodel.2005.07.008
Abstract
A model was developed to explore patterns of carbon flow through the pelagic food web of Lake Fryxell, Taylor Valley,
Antarctica. The goals of this study were to quantify patterns of carbon flow and test hypotheses of top-down versus bottom-up
controls on this system. The model included seven trophic groups: bacteria, photosynthetic nanoflagellates (PNAN), heterotrophic
nanoflagellates (HNAN), ciliates (bacterial feeding and flagellate feeding), phytoplankton and rotifers (the top predator); all
inputs were driven by predatory demands. This system has no insects, vertebrates, crustacea or allochthonous inputs from
terrestrial plants. Autotrophs and bacteria contributed ca. 94% of total community biomass, with all other heterotrophic organisms
representing <6% of the total. We defined a measure of trophic efficiency (λ) as the ratio of carbon uptake by rotifers to total
carbon uptake by all trophic groups. λ was always <2% of total community carbon flow and seldom correlated to other flows
of carbon through the system. Sensitivity analysis revealed that λ was relatively insensitive to efficiency of carbon transfers
between other components of the food web. In total, these results suggest little top-down influence of the top predator on system
dynamics. Conversely, major fluctuations in total community biomass followed general patterns of seasonal and inter-annual
availability of PAR, suggesting bottom-up control on this system.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | microbial loop, carbon flow, model, Antarctica |
| Research Division: | Biological Sciences |
| Research Group: | Microbiology |
| Research Field: | Microbial ecology |
| Objective Division: | Environmental Management |
| Objective Group: | Management of Antarctic and Southern Ocean environments |
| Objective Field: | Biodiversity in Antarctic and Southern Ocean environments |
| UTAS Author: | Laybourn-Parry, J (Professor Johanna Laybourn-Parry) |
| ID Code: | 49094 |
| Year Published: | 2006 |
| Web of Science® Times Cited: | 6 |
| Deposited By: | Research Division |
| Deposited On: | 2007-11-13 |
| Last Modified: | 2012-11-13 |
| Downloads: | 0 |
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