Hypoxia-induced structural changes in the diet of bottom-feeding fish and Crustacea
Hypoxia-induced structural changes in the diet of bottom-feeding fish and Crustacea
复制标题
缺氧引起的底栖鱼类和甲壳类动物的饮食结构变化
DOI：
10.1007/bf00356279
复制
发表时间：
1992
期刊：
影响因子：
2.4
通讯作者：
L. Schaffner
中科院分区：
文献类型：
--
作者：
L. Pihl;S. Baden;R. Díaz;L. Schaffner
1989年，在美国弗吉尼亚州切萨皮克湾的约克河，研究了三种交替的常氧-低氧循环对移动的鱼类（斑点鱼，Leiostomus xanthurus;和猪颈鱼，三点三鳍鱼）和穴居甲壳动物（Squilla empusa）的底栖猎物开发的相互影响。在四个深度层（A：5至10米; B：10至14米; C：14至20米; D：>20米）收集的捕食者不同程度地受到缺氧的影响，被分成大小类（3个斑点和2个每个hogchoker和螳螂虾），以检查潜在的个体发育的影响，在猎物选择。缺氧对底栖生物的影响最严重的发生在两个最深的层（C和D），在较浅的层（B>A）中减少，层A从未受到低氧的影响。捕食者调查表现出最佳的猎物开发期间或缺氧事件后立即饮食的证据。在大多数情况下，肠道内容物包含显着更大，更深的穴居猎物在低氧期间比在正常氧气水平的交替期间。现场消耗了更大的生物量（45至73%）的多毛类比其他猎物，甲壳类动物最初也构成了主要的饮食成分，但在研究期间的重要性下降。深穴海葵（Edwardsiaelegans）是斑节蜱的重要捕食物种，特别是在受缺氧影响的较低深度地层中。10至15厘米长的斑点消耗的猎物的大小显着增加，在一些缺氧事件，表明缺氧对大型底栖物种的亚致死效应。多毛类（主要是美洲甘油脂，Notomastis latericeus和Loimia medusa）是占主导地位的饲料成分在hogchoker，占85%和98%之间的饮食。在三个最深的地层中，双壳类虹吸管成为hogchoker的重要猎物，只有在8月缺氧后才被消耗。在大多数情况下，螳螂虾的胃内容物很难识别，因为它们几乎完全咀嚼了所消耗的猎物。甲壳类动物最初是重要的猎物，但在7月缺氧事件之后的饮食中变得不那么显眼，此时水螅虫变得更加占主导地位。总体而言，捕食者物种表现出最佳的开发垂死或缓慢恢复的底栖生物缺氧的影响。缺氧的亚致死效应，通过增加底栖生物的可用性，以驻地食肉动物可以有重要的后果，能源流动的地区，如约克河，经历周期性的低氧循环。
Interactive effects of three alternating normoxia-hypoxia cycles on benthic prey exploitation by mobile fish (spot, Leiostomus xanthurus; and hogchoker, Trinectes maculatus) and a burrowing crustacean (Squilla empusa) were investigated in the York River, Chesapeake Bay, Virginia, USA, in 1989. Predators collected in four depth strata (A: 5 to 10 m; B: 10 to 14 m; C: 14 to 20 m; D:>20 m) variously affected by hypoxia were separated into size classes (three for spot and two each for hogchoker and mantis shrimp) to examine potential ontogenetic influences in prey selection. The most severe effects of hypoxia on the benthos occurred in the two deepest strata (C and D) and decreased in shallower strata (B>A), with Stratum A never affected by low oxygen. Predators investigated exhibited dietary evidence of optimal prey exploitation during or immediately after hypoxic events. In most instances gut contents contained significantly larger, deeper-burrowing prey during periods of low oxygen than during alternating peroids of normal oxygen levels. Spot consumed a greater biomass (45 to 73%) of polychaetes than other prey, with crustaceans initially also constituting a main dietary component but decreasing in importance later in the study period. The deep-burrowing anemone, Edwardsia elegans, was an important prey species for spot, particularly in the lower depth strata affected by hypoxia. Prey consumed by 10-to 15-cm-long spot increased significantly in size during some hypoxic events, suggesting a sublethal effect of hypoxia on large benthic species. Polychaetes (primarily Glycera americana, Notomastis latericeus and Loimia medusa) were dominant dietary components in hogchoker, making up between 85 and 98% of the diet. Bivalve siphons became important prey for hogchoker in the three deepest strata and were only consumed after the August hypoxia. Stomach contents of mantis shrimp were difficult to identify in most instances due to the near complete mastication of consumed prey. Crustaceans were important prey initially but became less conspicuous in the diet subsequent to the July hypoxia event, when hydroids became more dominant. Overall, predator species exhibited optimal exploitation of moribund or slowly recovering benthos affected by hypoxia. The sublethal effects of hypoxia through increased availability of benthos to resident predators can have important consequences for energy flow in areas such as the York River which experience periodic low-oxygen cycles.