Organic matter pathways to zooplankton and benthos under pack ice in late winter and open water in late summer in the north-central Bering Sea
Organic matter pathways to zooplankton and benthos under pack ice in late winter and open water in late summer in the north-central Bering Sea
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DOI：
10.3354/meps291135
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发表时间：
2005-04
影响因子：
2.5
通讯作者：
J. Lovvorn;L. Cooper;M. Brooks;C. D. Ruyck;J. Bump;J. Grebmeier
中科院分区：
文献类型：
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作者：
J. Lovvorn;L. Cooper;M. Brooks;C. D. Ruyck;J. Bump;J. Grebmeier
在北极和亚北极海的大陆架上，春季冰缘消退时的水华所产生的大部分生物可能沉到海底，浮游动物几乎不吃草，从而维持了丰富的底栖生物群落。这种定居的浮游植物对大型底栖生物全年的重要性可能部分决定了冰盖长期变化的影响。我们研究了有机质（OM）的大型底栖动物和大型浮游动物下的冰盖在冬季末（3月至4月）和夏季末（9月）在白令海中北部的开放水域。2001年冬末，水柱中只有很小一部分OM是颗粒物。悬浮颗粒有机物（SPOM）和沉积物中的C：N比值、δ 13 C和δ 15 N表明，在冰盖地区，新鲜冰藻或浮游植物的近期输入非常少。对于3种主要以存款为食的双壳类，δ 13 C和δ 15 N显示了物种间相似的食物，在夏末和冬末之间以及在冰盖差异很大的冬末之间食物质量变化很小（1999年与2001年）。2001年冬季，从SPOM到沉积物（+3.2‰）和从沉积物到近地表沉积物-食物源（+1.6 ~+3.0‰），δ 13 C有较大的增加，而从SPOM到沉积物（+1.2‰）和从沉积物到沉积物-食物源（-0.3 ~+1.6‰），δ 15 N的差异较小。这些值表明，在这些非水华期间，近地表沉积物饲养者的饮食包括大量的细胞或产品的细菌，吸收了良好的再加工碳和同位素轻溶解无机氮（DIN）。到夏末和整个冬季，4至11个月后，春季开花，产品的细菌活动似乎是一个重要的途径OM进入底栖食物网。由于细菌对年度碳输入的依赖，以及用于繁殖无脊椎动物的新鲜浮游植物的独特营养成分，冰缘水华可能是大型底栖动物丰度年度变化的重要决定因素。
On continental shelves in arctic and subarctic seas, much of the production from spring blooms at the retreating ice edge may sink to the bottom with little grazing by zooplankton, thereby supporting abundant benthic communities. The importance of this settled phytoplankton to mac- robenthos throughout the year may partly determine effects of long-term changes in ice cover. We studied organic matter (OM) pathways to macrobenthos and macrozooplankton under ice cover in late winter (March-April) and open water in late summer (September) in the north-central Bering Sea. In late winter 2001, only a very small fraction of OM in the water column was particulate. C:N ratios, δ 13 C, and δ 15 N in suspended particulate organic matter (SPOM), and sediments indicated very little recent input of fresh ice algae or phytoplankton in ice-covered areas. For the 3 main deposit- feeding bivalves, δ 13 C and δ 15 N indicated similar diets among species, with minimal change in food quality between late summer and late winter, and between late winters with very different ice cover (1999 vs. 2001). In winter 2001, there were large increases in δ 13 C from SPOM to bulk sediments (+3.2‰) and from sediments to near-surface deposit-feeders (+1.6 to +3.0‰), but small differences in δ 15 N from SPOM to sediments (+1.2‰) and from sediments to deposit-feeders (-0.3 to +1.6‰). These values suggest that the diet of near-surface deposit-feeders during these non-bloom periods included substantial amounts of the cells or products of bacteria that had assimilated well-reworked carbon and isotopically light dissolved inorganic nitrogen (DIN). By late summer and through winter, 4 to 11 mo after the spring bloom, products of bacterial activity appeared to be an important route of OM into the benthic food web. Due to bacterial dependence on annual carbon inputs, and unique nutrient content of fresh phytoplankton for breeding invertebrates, ice-edge blooms might be an important determinant of annual variations in macrobenthic abundance.