Stable C and N isotopic composition of sinking particles and zooplankton over the southeastern Bering Sea shelf

Abstract

Stable carbon and nitrogen isotopic composition of zooplankton, suspended particulate organic matter (SPOM), and sinking particles collected using sediment traps were measured for samples obtained from the southeastern Bering Sea middle and outer shelf during 1997-1999. The quantity of material collected by the middle shelf sediment trap was greater in both spring and late summer and fall than in early and mid-summer. The d 15 N of SPOM, sinking material and zooplankton showed greater inter-annual variability at the middle shelf site (M2) than at the outer shelf site (M3). Zooplankton and sinking organic matter collected by M2 sediment traps became more depleted in 15 N from 1997 through 1999, associated with a change from unusually warm to unusually cold conditions. Suspended and sinking organic matter and zooplankton collected from M3 decreased only slightly in d15 N from 1998 to 1999. SPOM, zooplankton, and sediment trap samples collected at M2 were usually enriched in d 15 N and d 13 C over those from M3. However, in 1999 sediment trap samples from the middle shelf were enriched in 13 C over M3 material, but the d 15 N of samples from the two sites was similar. The geographic pattern could be explained greater productivity over the middle shelf, associated with either isotopically heavy nitrogen being regenerated from sediments, or with utilization of a greater fraction of the available inorganic nitrogen pool during most years. r

Carbon and nitrogen isotopic composition of particulate organic matter and its biogeochemical implication in the Bering Sea

“…NB01 to 1.46 μmol/dm 3 at Sta. B07 with an average of (0.92±0.37) μmol/dm 3 (Table 1) Continued from Table 1 3.3 13 C POC and 15 N PN 13 C POC and 15 N PN in the Bering Sea were listed in Table 1 and plotted for all stations along the sampling transects as shown in Figs 2e and f. 13 C POC dramatically varied from −29.93‰ to −20.26‰ with an average of (−24.21±1.97)‰, comparing well with those reported in previous studies in the Bering Sea (Smith et al, 2002;Guo, Tanaka et al, 2004), but somewhat lighter than those from the western Arctic Ocean (Zhang et al, 2012). In addition, 13 C POC values in the Bering Sea were lighter than those observed in tropical, subtropical or temperate seas, such as the southwestern Indian Ocean (Francois et al, 1993), the northeastern Pacific Ocean (Wang et al, 1998) and the Bohai Bay (Gao et al, 2012).…”

Increases in jellyfish biomass in the Bering Sea: implications for the ecosystem

“…Thus the trophic level of an organism increases when coccolithophores are the main primary producers. Smith & Heinrichs (2002) also found anomalously high δ 13 C and δ 15 N values in plankton and sediment trap samples collected in 1999 compared to 1997 and 1998, which they attributed to the early and prolonged coccolithophore bloom in 1999. Schell et al (1998) concluded that assessing trophic levels of top consumers must be done cautiously, because the natural range of isotope ratios can be very large.…”

Sources and characteristics of terrestrial carbon in Holocene-scale sediments of the East Siberian Sea

“…Topsoil-PF refers to organic matter from the active layer of permafrost, ICD-PF to relict Pleistocene Ice Complex deposit permafrost (yedoma) and marine OC to organic matter from primary production. The endmember values for different sources are taken from a dataset compiled by Vonk et al (2012) and a study by Smith et al (2002). The green arrow points to the direction from the bottom to the top of the core (GC58).…”