GEOMAR, Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA.
Proc Biol Sci. 2017 Dec 20;284(1869). doi: 10.1098/rspb.2017.2096.
In many oceanic carbon budgets there is a discrepancy between the energetic requirements of deep-sea benthic communities and the supply of organic matter. This suggests that there are unidentified and unmeasured food sources reaching the seafloor. During 11 deep-sea remotely operated vehicle (ROV) surveys in the Gulf of California, the remains (squid carcasses and hatched-out egg sheets) of 64 post-brooding squid were encountered. As many as 36 remains were encountered during a single dive. To our knowledge this is one of the largest numbers of natural food falls of medium-size deep-sea nekton described to date. Various deep-sea scavengers (Ophiuroidea, Holothuroidea, Decapoda, Asteroidea, Enteropneusta) were associated with the remains. Although many of the 80 examined ROV dives did not encounter dead squids or egg sheets ( = 69), and the phenomenon may be geographically and temporally restricted, our results show that dead, sinking squid transport carbon from the water column to the seafloor in the Gulf of California. Based on food fall observations from individual dives, we estimate that annual squid carcass depositions may regionally contribute from 0.05 to 12.07 mg C m d to the seafloor in the areas where we observed the remains. The sinking of squid carcasses may constitute a significant but underestimated carbon vector between the water column and the seafloor worldwide, because squid populations are enormous and are regionally expanding as a result of climate change and pressure on fish stocks. In the future, standardized methods and surveys in geographical regions that have large squid populations will be important for investigating the overall contribution of squid falls to regional carbon budgets.
在许多海洋碳预算中，深海底栖生物群落的能量需求与有机物质的供应之间存在差异。这表明，有未被识别和测量的食物来源到达海底。在加利福尼亚湾的 11 次深海遥控潜水器 (ROV) 调查中，遇到了 64 条育后鱿鱼的遗骸（鱿鱼尸体和孵化出的卵片）。在一次潜水过程中，最多遇到了 36 个遗骸。据我们所知，这是迄今为止描述的最大数量的中型深海浮游动物自然食物坠落之一。各种深海食腐动物（蛇尾纲、海参纲、十足目、海星纲、肠鳃纲）与遗骸有关。尽管在 80 次检查过的 ROV 潜水中有许多没有遇到死鱿鱼或卵片（=69），而且这种现象可能在地理和时间上受到限制，但我们的结果表明，死亡的、下沉的鱿鱼将碳从水柱输送到加利福尼亚湾的海底。根据单次潜水的食物坠落观察，我们估计每年鱿鱼尸体的沉积可能会使该地区的海底每年从 0.05 到 12.07 毫克 C m d 区域贡献碳。鱿鱼尸体的下沉可能构成了水柱和海底之间一个重要但被低估的碳载体，因为鱿鱼数量巨大，并且由于气候变化和对鱼类种群的压力，在区域内不断扩张。未来，在有大量鱿鱼种群的地理区域采用标准化方法和调查，对于调查鱿鱼坠落对区域碳预算的总体贡献将非常重要。
