Ostrom Peggy H, Wiley Anne E, James Helen F, Rossman Sam, Walker William A, Zipkin Elise F, Chikaraishi Yoshito
Department of Integrative Biology and Ecology Evolutionary Biology and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
Department of Biology, University of Akron, Akron, OH 44325, USA.
Proc Biol Sci. 2017 Mar 29;284(1851). doi: 10.1098/rspb.2016.2436.
Human-induced ecological change in the open oceans appears to be accelerating. Fisheries, climate change and elevated nutrient inputs are variously blamed, at least in part, for altering oceanic ecosystems. Yet it is challenging to assess the extent of anthropogenic change in the open oceans, where historical records of ecological conditions are sparse, and the geographical scale is immense. We developed millennial-scale amino acid nitrogen isotope records preserved in ancient animal remains to understand changes in food web structure and nutrient regimes in the oceanic realm of the North Pacific Ocean (NPO). Our millennial-scale isotope records of amino acids in bone collagen in a wide-ranging oceanic seabird, the Hawaiian petrel (), showed that trophic level declined over time. The amino acid records do not support a broad-scale increase in nitrogen fixation in the North Pacific subtropical gyre, rejecting an earlier interpretation based on bulk and amino acid specific N chronologies for Hawaiian deep-sea corals and bulk N chronologies for the Hawaiian petrel. Rather, our work suggests that the food web structure in the NPO has shifted at a broad geographical scale, a phenomenon potentially related to industrial fishing.
人为引起的公海生态变化似乎正在加速。渔业、气候变化和营养物质输入增加都被不同程度地指责，至少部分地导致了海洋生态系统的改变。然而，评估公海人为变化的程度具有挑战性，因为那里生态状况的历史记录稀少，且地理范围巨大。我们通过保存在古代动物遗骸中的千年尺度氨基酸氮同位素记录，来了解北太平洋海洋区域（NPO）食物网结构和营养状况的变化。我们对广泛分布的海洋海鸟——夏威夷海燕（）骨骼胶原蛋白中氨基酸的千年尺度同位素记录显示，营养级随时间下降。这些氨基酸记录不支持北太平洋亚热带环流区氮固定的大规模增加，这与基于夏威夷深海珊瑚的总量和氨基酸特定氮年代学以及夏威夷海燕的总量氮年代学的早期解释相悖。相反，我们的研究表明，北太平洋海洋区域的食物网结构在广泛的地理尺度上发生了变化，这一现象可能与工业捕鱼有关。
