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The influence of nitrogen limitation on d15N and carbon : nitrogen ratios in sediments from sockeye salmon nursery lakes in British Columbia, Canada
Author(s) -
Brahney Janice,
Bos Darren G.,
Pellatt Marlow G.,
Edwards Thomas W. D.,
Routledge Richard
Publication year - 2006
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2006.51.5.2333
Subject(s) - sediment , δ15n , nitrogen , environmental science , abundance (ecology) , isotopes of nitrogen , oceanography , nutrient , organic matter , environmental chemistry , δ13c , ecology , geology , stable isotope ratio , chemistry , biology , paleontology , physics , organic chemistry , quantum mechanics
Carbon (C) and nitrogen (N) elemental and nitrogen isotopic ratios were determined for bulk organic matter in surface sediments of 11 sockeye salmon ( Onchorynchus nerka ) nursery lakes in British Columbia, Canada. Chitinous exoskeletons of Bosmina spp. were also picked from the sediments and analyzed for Δ 15 N. The correlation between salmon escapement (spawner abundance) and bulk organic Δ 15 N confirms the importance of marine‐derived nitrogen to the study lakes. The relation between sediment Δ 15 N and escapement, however, suggests that simple mixing models may significantly underestimate spawner abundance in nitrogen‐limited lakes. In addition, the use of sediment and chitin Δ 15 N and C:N data to characterize lake‐specific differences demonstrates that sediment isotope signatures are dependent on attendant nitrogen deficiency. The sediment C:N ratio, on its own, provides a sensitive measure of nutrient status in these lakes. This finding provides an alternate additional interpretation of C:N ratios that may be more appropriate in large lakes where terrestrial contributions to the central basin are insignificant.