Kline, T. C.. Prince William Sound Science Center, tkline@grizzly.pwssc.gen.ak.us
, . C.. ,

 
SHIFTS IN NATURAL CARBON AND NITROGEN ISOTOPE COMPOSITION BASED FOOD WEB DEPENDENCIES PROVIDE EVIDENCE OF BIOPHYSICAL COUPLING IN PRINCE WILLIAM SOUND, ALASKA
 
The advective regime connecting the northern Gulf of Alaska (GOA) with Prince William Sound (PWS), Alaska is hypothesized to control recruitment and nutritional processes in juvenile fishes directly, by altering planktonic food sources, and indirectly, by altering feeding habits of potential predators. Changes in the natural abundance of C-13/C-12 and N-15/N-14 measured in fishes and plankton provides the linkages needed to test these hypotheses. The large copepods of the genus Neocalanus, a proxy for pelagic production sources, from GOA had distinctive delC-13 signatures compared to those from PWS. Additionally, PWS delC-13 was consistent while GOA delC-13 varied by 5 per mil among spring blooms. The relative affinity of juvenile fishes for GOA or PWS carbon was determined with their delC-13 while incorporating trophic level and lipid normalization using their delN-15 and C/N, respectively. Fish affinity range was large and changed on annual time scales. There was a shift to a greater dependency on GOA carbon in 1995 compared with 1994. A shift to high GOA delC-13 values during the 1996 spring bloom effected a systemic increase in fish delC-13. GOA origin Neocalanus undergoing diapause (resting phase) confirmed the influx of GOA zooplankton.
 
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
 
Code: SS32TU1337S