Depth gradients in food-web processes linking habitats in large lakes: Lake Superior as an exemplar ecosystem

Freshwater Biology
By: , and 

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Abstract

  1. In large lakes around the world, depth-based changes in the abundance and distribution of invertebrate and fish species suggest that there may be concomitant changes in patterns of resource allocation. Using Lake Superior of the Laurentian Great Lakes as an example, we explored this idea through stable isotope analyses of 13 major fish taxa.
  2. Patterns in carbon and nitrogen isotope ratios revealed use of both littoral and profundal benthos among populations of most taxa analysed regardless of the depth of their habitat, providing evidence of nearshore–offshore trophic linkages in the largest freshwater lake by area in the world.
  3. Isotope-mixing model results indicated that the overall importance of benthic food-web pathways to fish was highest in nearshore species, whereas the importance of planktonic pathways increased in offshore species. These characteristics, shared with the Great Lakes of Africa, Russia and Japan, appear to be governed by two key processes: high benthic production in nearshore waters and the prevalence of diel vertical migration (DVM) among offshore invertebrate and fish taxa. DVM facilitates use of pelagic food resources by deep-water biota and represents an important process of trophic linkage among habitats in large lakes.
  4. Support of whole-lake food webs through trophic linkages among pelagic, profundal and littoral habitats appears to be integral to the functioning of large lakes. These linkages can be disrupted though ecosystem disturbance such as eutrophication or the effects of invasive species and should be considered in native species restoration efforts.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Depth gradients in food-web processes linking habitats in large lakes: Lake Superior as an exemplar ecosystem
Series title Freshwater Biology
DOI 10.1111/fwb.12415
Volume 59
Issue 10
Year Published 2014
Language English
Publisher Wiley
Contributing office(s) Great Lakes Science Center
Description 15 p.
First page 2122
Last page 2136
Country Canada, United States
Other Geospatial Lake Superior
Online Only (Y/N) N
Additional Online Files (Y/N) N