Collaborative Research: The Chemical Ecology of Shallow-Water Marine Macroalgae and Invertebrates on the Antarctic Peninsula

0125181阿姆斯勒南极帕尔默站附近的底栖海洋生态系统为研究海洋生物化学防御的功能和进化提供了一个很好的场所。南极洲的独特之处在于海星和其他无脊椎动物是底栖动物的主要捕食者。海星与其他咬人的食肉动物很不一样，因为它们经常通过将心脏胃挤压到猎物上方进行外部消化来进食。这种喂养模式应该是一个特别强大的选择力，表面封存的化学防御，特别是在南极洲，海星是主要的海绵捕食者和咬海绵动物是相对罕见的。南极海星是缓慢移动的掠食者，长时间以单个海绵为食，并且可能有斑块分布。然而，它们比小型食草动物大得多，这些小型食草动物被认为在低纬度地区诱导化学防御方面很重要。研究人员以前的研究已经确定了次级代谢产物在各种各样的固着和迟缓的无脊椎海洋无脊椎动物和海洋大型藻类中的存在和生态作用。目前的项目集中在两组关于化学防御的功能和进化的问题。首先，最佳防御理论和植物和动物化学防御的诱导防御模型的预测将被测试。前一种理论预测，化学防御将在最容易被捕食的组织中被差异化地隔离。后者的理论预测，这样的捕食者应该选择诱导防御和这些南极捕食者-猎物的关系提供了机会，从模型的基本预测捕食者的大小分离的问题。其次，研究人员建议利用南极半岛丰富的大型藻类植物群和南极洲沿海独特的营养环境的生态主导成员，以测试预测的多种，在棕色大型藻类的次生代谢产物的相互作用，包括诱导防御模型的预测。另一项测试将审查大气臭氧消耗造成的浅水底栖生物群落紫外线辐射增加是否会影响次级代谢物的产生。由于这些大型藻类在其社区中占主导地位，了解影响其营养关系的因素对于了解整个社区动态非常重要。研究人员计划继续大力追求和促进机会，将他们的科学研究与各种教育活动相结合，包括支持本科生，以及研究生和研究生研究;和科学教师通过NSF教师体验南极洲计划。

0125181AmslerThe benthic marine ecosystem near Palmer Station, Antarctica provides an excellent site for the study of the function and evolution of chemical defenses in marine organisms. Antarctica is unique in that sea stars and other invertebrates are the major predators on benthic animals. Sea stars are quite different from other, biting predators because they often feed by extruding their cardiac stomach over their prey for external digestion. This feeding pattern should be a particularly strong selective force for surface-sequestration of chemical defenses, especially in Antarctica where sea stars are the major sponge predator and biting spongivores are relatively uncommon. Antarctic sea stars are slow moving predators that feed on individual sponges for long periods of time and can have patchy distributions. However, they are much larger than the small grazers thought to be important in inducing chemical defenses at lower latitudes. Previous studies by the investigators have established the presence and ecological role of secondary metabolites in a wide variety of sessile and sluggish antarctic marine invertebrates and in marine macroalgae. The current project focus on two sets of questions concerning the function and evolution of chemical defenses. First, the predictions of the Optimal Defense Theory and the Induced Defense Model of plant and animal chemical defenses will be tested. The former theory predicts that chemical defenses will be differentially sequestered in tissues that are most susceptible to predation. The latter theory predicts that such predators should select for inducible defenses and these Antarctic predator-prey relationships provide the opportunity to separate the issue of predator size from the basic predictions of the model. Second, the investigators propose to utilize the ecologically dominant members of the Antarctic Peninsula's rich macroalgal flora and the distinctive nutrient environment of coastal Antarctica to test predictions of multiple, interactive roles for secondary metabolites in brown macroalgae including predictions of the Induced Defense Model. An additional test will examine whether increased ultraviolet radiation in shallow water benthic communities caused by atmospheric ozone depletion might be affecting secondary metabolite production. Because of the dominance of these macroalgae in their communities, understanding factors that influence their trophic relationships are important for understanding community dynamics as a whole. The investigators plan to continue to vigorously pursue and foster opportunities to integrate their scientific research with a variety of educational activities, including supporting undergraduate, as well as graduate and postgraduate research; and science teachers through the NSF Teachers Experiencing Antarctica program.