Net pelagic heterotrophy in mesotrophic and oligotrophic basins of a large, temperate lake

Bass, A. M., Waldron, S. , Preston, T. and Adams, C. E. (2010) Net pelagic heterotrophy in mesotrophic and oligotrophic basins of a large, temperate lake. Hydrobiologia, 652(1), pp. 363-375. (doi:10.1007/s10750-010-0369-6)

Full text not currently available from Enlighten.

Abstract

Understanding the effects of trophic status and dissolved organic carbon concentration (DOC) on lake carbon cycling is essential for accurate ecosystem carbon models. Using isotopically labelled substrates we assessed spatial and temporal variability in bacterial respiration (BR) and algal primary production (PP) in two trophically, morphometrically and hydrologically different basins in Loch Lomond, a large temperate lake in Scotland. GIS modelling was used to construct a whole lake balance for bacterial production/respiration and PP, and from this the proportion of heterotrophy fuelled by allochthonous carbon was estimated. We tested the hypotheses that trophic status and DOC concentration affect the balance between PP and BR and examined which is the more significant driving factor. Additionally we estimated the percentage of BR that is fuelled by terrestrial carbon. PP varied seasonally and showed inter-basin homogeneity. BR was greatest in the mesotrophic south basin in autumn, which corresponded to measured peak DOC input, though over an annual cycle no relationship was observed between BR and DOC concentration. The PP:BR ratio was 0.37 ± 0.30 and 0.3 ± 0.45 in the north and south basins, respectively, assuming a bacterial growth efficiency of 0.1. We have found that allochthonous carbon potentially supports a substantial quantity of pelagic production, even during periods of high photosynthesis. Less productive systems are thought to be dominated by heterotrophic processes. However, we have found that the mesotrophic basin of a large lake to be as heterotrophic as its neighbouring oligotrophic basin, an observation that has implications for our understanding of modelling of the role of lakes in linking the terrestrial-atmospheric carbon cycle.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Waldron, Professor Susan and Preston, Professor Thomas and Bass, Dr Adrian and Adams, Professor Colin
Authors: Bass, A. M., Waldron, S., Preston, T., and Adams, C. E.
Subjects:G Geography. Anthropology. Recreation > G Geography (General)
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:Hydrobiologia
Publisher:Springer Netherlands
ISSN:0018-8158
ISSN (Online):1573-5117
Published Online:11 July 2010

University Staff: Request a correction | Enlighten Editors: Update this record