新西兰学者首次利用同位素技术调查了南极深海生物食物网的营养结构。分析了麦克默多海峡和维多利亚海岸5个地点的初级生产者（如海藻）和海洋杂食动物肌体组织的同位素组成及动物内脏内的食物组成。肌体组织包括肌肉组织、外壳组织或者表皮组织。内脏内物质组成可以反映近期所摄取的食物状况，而肌体组织的同位素值则反映长时期内的食物源组成。
分析结果表明，不同的初级生产者和其它的基础性食物源以及动物肌体组织的同位素值（d13C和d15N）差异很大，并且在不同地点之间变化很大。这些地点包括从永久性厚冰覆盖的海域到富产海藻的无冰海域。海冰分布状况能限制海域的初级生产力，这反映出空间上有机物的补给及其连通性在食物网中的重要地位和作用。不同研究地点同位素值的差异结果为预测未来深海生态系统对南极洲海冰厚度变化的响应提供了基础。
相关论文发表在《生态学》（Ecology）上。（科学新闻杂志 徐雨晴/编译）
生物谷推荐原始出处：
（Ecology），Volume 88, Issue 11，pp. 2810–2820，A. Norkko，A.-M. Schwarz
TROPHIC STRUCTURE OF COASTAL ANTARCTIC FOOD WEBS ASSOCIATED WITH CHANGES IN SEA ICE AND FOOD SUPPLY
A. Norkko1,3, S. F. Thrush1, V. J. Cummings2, M. M. Gibbs1, N. L. Andrew2,4, J. Norkko1,3, and A.-M. Schwarz1,5
1 National Institute of Water and Atmospheric Research, P.O. Box 11-115, Hamilton, New Zealand
2 National Institute of Water and Atmospheric Research, P.O. Box 14-901, Wellington, New Zealand
Predicting the dynamics of ecosystems requires an understanding of how trophic interactions respond to environmental change. In Antarctic marine ecosystems, food web dynamics are inextricably linked to sea ice conditions that affect the nature and magnitude of primary food sources available to higher trophic levels. Recent attention on the changing sea ice conditions in polar seas highlights the need to better understand how marine food webs respond to changes in such broad-scale environmental drivers. This study investigated the importance of sea ice and advected primary food sources to the structure of benthic food webs in coastal Antarctica. We compared the isotopic composition of several seafloor taxa (including primary producers and invertebrates with a variety of feeding modes) that are widely distributed in the Antarctic. We assessed shifts in the trophic role of numerically dominant benthic omnivores at five coastal Ross Sea locations. These locations vary in primary productivity and food availability, due to their different levels of sea ice cover, and proximity to polynyas and advected primary production. The δ15N signatures and isotope mixing model results for the bivalves Laternula elliptica and Adamussium colbecki and the urchin Sterechinus neumeyeri indicate a shift from consumption of a higher proportion of detritus at locations with more permanent sea ice in the south to more freshly produced algal material associated with proximity to ice-free water in the north and east. The detrital pathways utilized by many benthic species may act to dampen the impacts of large seasonal fluctuations in the availability of primary production. The limiting relationship between sea ice distribution and in situ primary productivity emphasizes the role of connectivity and spatial subsidies of organic matter in fueling the food web. Our results begin to provide a basis for predicting how benthic ecosystems will respond to changes in sea ice persistence and extent along environmental gradients in the high Antarctic.
