新西蘭學(xué)者首次利用同位素技術(shù)調(diào)查了南極深海生物食物網(wǎng)的營養(yǎng)結(jié)構(gòu),。分析了麥克默多海峽和維多利亞海岸5個地點的初級生產(chǎn)者（如海藻）和海洋雜食動物肌體組織的同位素組成及動物內(nèi)臟內(nèi)的食物組成。肌體組織包括肌肉組織,、外殼組織或者表皮組織,。內(nèi)臟內(nèi)物質(zhì)組成可以反映近期所攝取的食物狀況，而肌體組織的同位素值則反映長時期內(nèi)的食物源組成,。
分析結(jié)果表明,，不同的初級生產(chǎn)者和其它的基礎(chǔ)性食物源以及動物肌體組織的同位素值（d13C和d15N）差異很大，并且在不同地點之間變化很大,。這些地點包括從永久性厚冰覆蓋的海域到富產(chǎn)海藻的無冰海域,。海冰分布狀況能限制海域的初級生產(chǎn)力，這反映出空間上有機物的補給及其連通性在食物網(wǎng)中的重要地位和作用,。不同研究地點同位素值的差異結(jié)果為預(yù)測未來深海生態(tài)系統(tǒng)對南極洲海冰厚度變化的響應(yīng)提供了基礎(chǔ)。
相關(guān)論文發(fā)表在《生態(tài)學(xué)》（Ecology）上,。（科學(xué)新聞雜志 徐雨晴/編譯）
生物谷推薦原始出處：
（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.
