Isotopic analysis of the sources of organic carbon for zooplankton in shallow subarctic and arctic waters

• DOI: 10.1111/j.0906-7590.2007.04462.x
• Publication Date: 2007-11-07T07:02:53Z
• Authors: Milla Rautio; Warwick F. Vincent
• Keywords: Subarctic climate; Seston; Isotope Analysis

Shallow high‐latitude lakes and ponds are usually characterized by an oligotrophic water column overlying a biomass‐rich, highly productive benthos. Their pelagic food webs often contain abundant zooplankton but the importance of benthic organic carbon versus seston as their sources has been little explored. Our objectives were to measure δ 13 C 15 N isotopic signatures particulate matter (POM) in shallow bodies northern Canada determine relative transfer this material other aquatic invertebrates. Fluorescence analysis colored dissolved (CDOM) indicated relatively strong terrestrial influence five subarctic waterbodies whereas CDOM arctic columns contained mostly autochthonous origin. The planktonic POM cohesive microbial mats distinctly different at all study sites, while non‐cohesive overlapped signals with POM. Zooplankton potential trophic link fractions did not appear be used major source. differed among species, indicating selective use resources niche partitioning. Most had values that intermediate between putative likely reflected feeding on components or results emphasize benthic‐pelagic coupling tundra ecosystems, including for species traditionally considered previously thought dependent only phytoplankton