*Department of Biological Sciences, Mt Holyoke College, South Hadley, MA 01075, USA.
Integr Comp Biol. 2008 Dec;48(6):808-22. doi: 10.1093/icb/icn052. Epub 2008 Jun 21.
Bryozoans are suspension feeding colonial animals that remain attached to the substratum or other surfaces. How well a bryozoan can feed in a particular flow regime could help determine the distribution and abundance of that bryozoan. I tested how velocity of flow affects feeding rate in four species of bryozoans in the laboratory and how these species perform in different flow regimes in the field. I found that one species, Membranipora membranacea, had a higher ingestion rate than did the other three species at all velocities of flow tested. Membranipora also had a higher rate of ingestion at intermediate velocities, while velocity did not have as strong an effect on ingestion rate in the other three species. As predicted from the feeding experiments, all four species generally had greater abundance, attained a larger size, grew faster, and survived longer in flow regimes in which feeding is higher. Also as predicted, Membranipora had greater abundance, attained a larger size, grew faster, and survived longer than did the other three species both in slower and faster flow regimes in the field. Understanding how flow affects feeding can help predict the distribution and abundance of bryozoans in the field. Because especially efficient filterers like Membranipora can grow faster and have higher survival under a wide range of conditions of flow, this species may be able to outcompete many other species or take advantage of ephemeral habitats, thereby becoming a potentially effective invasive species as has been seen in the Gulf of Maine.
苔藓动物是附着在基质或其他表面上的悬浮滤食性群体动物。苔藓动物在特定水流条件下的滤食能力如何，可能有助于确定该苔藓动物的分布和丰度。我在实验室中测试了流速如何影响 4 种苔藓动物的摄食率，并测试了这些物种在野外不同水流条件下的表现。结果发现，在所有测试流速下，一种名为 Membranipora membranacea 的物种的摄食率均高于其他 3 种。Membranipora 在中等流速下的摄食率也更高，而在其他 3 种物种中，流速对摄食率的影响并不那么强烈。正如摄食实验所预测的那样，所有 4 种物种在摄食率较高的水流条件下通常具有更高的丰度、更大的体型、更快的生长速度和更长的存活时间。与预测一致的是，Membranipora 在野外的慢流速和快流速条件下都比其他 3 种物种具有更高的丰度、更大的体型、更快的生长速度和更长的存活时间。了解水流如何影响摄食，可以帮助预测苔藓动物在野外的分布和丰度。由于像 Membranipora 这样特别高效的滤食者在广泛的水流条件下能够更快地生长和具有更高的存活率，因此该物种可能能够与许多其他物种竞争或利用短暂的栖息地，从而成为一种潜在的有效入侵物种，这在缅因湾已经得到了证实。
