The carbon and nitrogen isotopic compositions of particulate organic matter in the subarctic northeast Pacific Ocean ...

• Main Author: Wu, Jinping
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Subarctic
• Online Access: https://dx.doi.org/10.14288/1.0053274; https://doi.library.ubc.ca/10.14288/1.0053274

The aim of this study was to determine the variations of δ¹³C and δ¹⁵N of particulate organic matter (POM) and the factors that control the isotopic fractionation from inorganic substrates to zooplankton and lead to variations in the isotopic composition of suspended and sinking POM in the subarctic northeast Pacific Ocean. Along a transect from Station L (48°39'N, 126°40'W) to Station P (50°N, 145°W), surface δ¹⁵NO₃⁻ decreased from 11.2‰ to 7.6‰, while [NO₃⁻] increased from 3 to 12 pM. The δ¹⁵N trends for bulk POM, < 5 pm POM, 50-253 pm POM, < 253 pm POM and zooplankton were similar to that for nitrate. The fractionation factor (e) for the nitrogen isotopes was 5‰. Trophic enrichment of ¹⁵N was observed with mesozooplankton being isotopically heavier than suspended POM by 3.9‰ at Station P and 2.2‰ at Station L. The range of δ¹⁵N among six zooplankton groups was 3.7‰. At Station P, sinking δ¹³C[sub POM] and δ¹⁵N[sub POM] at 3800 m between 1982 and 1990 show significant annual changes. The δ¹³C[sub ...