Widbom Bertil, Frithsen Jeffrey B
Marine Ecosystems Research Laboratory Graduate School of Oceanography, University of Rhode Island, 02882, Narragansett, RI, USA.
Oecologia. 1995 Feb;101(2):156-168. doi: 10.1007/BF00317279.
The quantitative development and uptake of radio-labelled phytodetritus in benthic macro- and meiofauna was studied in a 5-month experiment in two mesocosms, one of which received a single large nutrient (N and P) addition, while the other served as control. In reponse to the 12-fold increase in phytoplankton biomass noted after 2 weeks and the resulting enhanced accumulation of fresh phytodetritus, the abundance and biomass of the polychaetes Mediomastus ambiseta and Polydora ligni and the mud anemone Cerianthiopsis americanus increased significantly in the enriched tank. The abundances of P. ligni and M. ambiseta increased 37-fold and 12-fold, respectively, within the first two months of the experiment. No other macrofaunal or meiofaunal taxa showed any consistent positive quantitative response to the increased input of phytodetritus. In the control tank no considerable change in the benthic community structure was noted. The measurements of radio-label uptake within the benthic fauna showed that the quantitatively most successful species utilized fresh phytodetritus highly. However, a high degree of utilization of fresh detritus was also shown by taxa that did not respond quantitatively within the 5 month of the experiment, and almost all taxa showed a preference for fresh detritus over older organic material. Within the benthic meiofauna, kinorhynchs and especially foraminiferans showed a remarkably low preference for fresh detritus. A budget calculation comparing the total amounts of labelled organic carbon bound in animal tissue and in the sediment indicated that at any time at least 75% of this carbon was available for assimilation by deposit feeders. These results suggest that factors other than the availability of food, such as competition for space by a few opportunistic macrofauna species, limited the response of other species within this benthic community to the increased input of phytodetritus.
在两个中型生态系统中进行了为期5个月的实验，研究了底栖大型和小型动物对放射性标记的植物碎屑的定量摄取和吸收情况。其中一个中型生态系统添加了单一的大量营养素（氮和磷），另一个作为对照。在2周后浮游植物生物量增加了12倍，并导致新鲜植物碎屑积累增加的情况下，富集水箱中多毛类动物双栖中柱虫和多齿沙蚕以及泥海葵美洲花筒螅的丰度和生物量显著增加。在实验的前两个月内，多齿沙蚕和双栖中柱虫的丰度分别增加了37倍和12倍。没有其他大型或小型动物类群对植物碎屑输入增加表现出任何一致的积极定量反应。在对照水箱中，底栖群落结构没有明显变化。对底栖动物体内放射性标记摄取的测量表明，数量上最成功的物种对新鲜植物碎屑的利用率很高。然而，在实验的5个月内没有定量反应的类群也表现出对新鲜碎屑的高度利用率，而且几乎所有类群都表现出对新鲜碎屑比对陈旧有机物质更有偏好。在底栖小型动物中，动吻动物，尤其是有孔虫对新鲜碎屑的偏好极低。一项比较动物组织和沉积物中结合的标记有机碳总量的预算计算表明，在任何时候，至少75%的这种碳可供沉积取食者同化。这些结果表明，除了食物供应外，其他因素，如少数机会主义大型动物物种对空间的竞争，限制了该底栖群落中其他物种对植物碎屑输入增加的反应。
