Incorporation of nitrogen and carbon from spawning coho salmon into the trophic system of small streams: evidence from stable isotopes
Bilby RE, Fransen BR, Bisson PA. 1996. Incorporation of nitrogen and carbon from spawning coho salmon into the trophic system of small streams: evidence from stable isotopes. Canadian Journal of Fisheries and Aquatic Sciences. 53:164-173
From the Abstract: "Epilithic organic matter, all aquatic macroinvertebrates except shredders, and fish were significantly enriched with 15N and 13C in streams (western Washington state, U.S.A.) where spawning coho salmon (Oncorhynchus kisutch) were present. Riparian vegetation adjacent to salmon-bearing streams and shredding macroinvertebrates were enriched with 15N but not 13C. The highest levels of enrichment of the stream biota with the heavier isotopes occurred in the early spring, shortly after carcasses had decomposed. Following spawning, age-0 coho salmon exhibited a doubling in rate of growth. Age-0 cutthroat trout in a nearby stream without salmon exhibited no change in growth rate during the winter. Salmon-derived organic matter was incorporated into the stream biota through direct consumption of eggs, carcasses, and fry and by sorption onto the streambed substrate of dissolved organic matter released by decomposing carcasses. Autotrophic uptake was not an important avenue of incorporation. The proportion of nitrogen contributed by spawning salmon varied among trophic categories, ranging from about 17% in collector-gatherers to more than 30% in juvenile coho salmon. Carbon contributed by spawning salmon ranged from 0% in the foliage of riparian plants and shredders to 34% in juvenile coho salmon."
- Type
- Journal Article
- Authors
- Bilby, Robert; Fransen, Brian; Bisson, Peter
- Units
- OLYM
- Keywords
- Coho Salmon (Oncorhynchus kisutch), Ecosystem Studies, Freshwater Stream, Nitrogen, Nutrient Cycling