科学家报告说，增加大气二氧化碳可能改变太平洋中最大的捕食者之一的洪堡乌贼的新陈代谢和行为。洪堡乌贼（Dosidicus gigas）见于太平洋热带东部地区，重量可达50公斤。
Rui Rosa和Brad Seibel收集了来自加利福尼亚湾的洪堡乌贼，从而调查变化的氧气和二氧化碳浓度导致的海洋酸化对动物的影响。此前的研究提示，气候变化可能导致海洋中的二氧化碳增加，并形成碳酸。在他们的船上进行的流动腔实验中，这组作者发现洪堡乌贼可以减缓它们的新陈代谢，仅使用非常少量的氧。这种乌贼因此可以在白天下潜到水下175米的缺氧区域。在夜间，这种乌贼依靠海面附近富含氧气的海水。然而，预计到2100年海面的海水具有更高的二氧化碳浓度，这可能改变深处的低氧海水和表面酸化海水之间的可生活窗口。
这组科学家说，结果将是这种乌贼可能变得昏睡，因此更容易被捕食者捕获，比目前更难抓到猎物，这可能迫使它们迁徙到别处。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS December 15, 2008, doi: 10.1073/pnas.0806886105
Synergistic effects of climate-related variables suggest future physiological impairment in a top oceanic predator
Rui Rosa1 and Brad A. Seibel
Department of Biological Sciences, University of Rhode Island, 100 Flagg Road, Kingston, RI 02881
By the end of this century, anthropogenic carbon dioxide (CO2) emissions are expected to decrease the surface ocean pH by as much as 0.3 unit. At the same time, the ocean is expected to warm with an associated expansion of the oxygen minimum layer (OML). Thus, there is a growing demand to understand the response of the marine biota to these global changes. We show that ocean acidification will substantially depress metabolic rates (31%) and activity levels (45%) in the jumbo squid, Dosidicus gigas, a top predator in the Eastern Pacific. This effect is exacerbated by high temperature. Reduced aerobic and locomotory scope in warm, high-CO2 surface waters will presumably impair predator–prey interactions with cascading consequences for growth, reproduction, and survival. Moreover, as the OML shoals, squids will have to retreat to these shallower, less hospitable, waters at night to feed and repay any oxygen debt that accumulates during their diel vertical migration into the OML. Thus, we demonstrate that, in the absence of adaptation or horizontal migration, the synergism between ocean acidification, global warming, and expanding hypoxia will compress the habitable depth range of the species. These interactions may ultimately define the long-term fate of this commercially and ecologically important predator.
