Seasonal variability of stable carbon and nitrogen isotope ratios of organisms in a North Pacific Bay

摘要: Abstract A survey of δ13C and δ15N organic carbon nitrogen in net phytoplankton, zooplankton, juvenile demersal fish benthic fauna sediments was made during the spring production cycle Auke Bay Fritz Cove marine embayments located southeastern Alaska. The values phytoplankton (>73 μm) increased bloom from −20·6±0·1%. (δ13C) + 3·3±0·6%. (δ15N) prebloom stage to −18·1±0·2%. +6·9±0·1%. following peak. Phytoplankton were significantly correlated with each other tempearture [+0·71%. per °C +0·58%. (δ15N)]. also a decline ambient nitrate concentration suggesting that primary source fueling bloom. Net macrozooplankton (>505 varied manner similar −21·2%. +7·2%. −18·2%. +8·2%. (> 165 were, on average, 0·5%. (Fritz Cove) 0·7%. (Auke Bay) heavier than their presumed food. Macrozooplankton average +3·2%. enriched 15N over phytoplankton. Values for flathead sole (80–100) mm) averaged −17·2±0·2%. pollock (120–130 −17·8±0·2%., which 3·1%. 2·5%., respectively, more positive 2·4%. 1·8%., μm). Sole +14·9±1·5%. +13·8±1·9%., 7·1%. 6·0%., zooplankton. sedimentary (−20·8±0·6%.) slightly depleted 13C compared (+5·9±1·0%.) supply major portion both sediments. Benthic invertebrates exhibited wide range (−20·8 −14·3%.) (+7·5 +12·8%.) values. Much variability is explained by trophic positions animals. adult Macoma nasuta significant seasonal shifts negative opposite Meiofauna (>98% nematodes) did not exhibit shift as zooplankton nasuta.