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

中食草动物，特别是端足类动物，是南极洲大型藻类群落的显著和主要组成部分。 尽管其高丰度，功能生态学，特别是南极端足类动物的营养关系知之甚少。 该项目将评估中食动物（体长约1至25毫米的小型无脊椎食肉动物）在南极半岛西部海洋群落中的重要性。这将通过研究中型草食动物在构建大型藻类群落中的作用，以及阐明中型食草动物与海底大型无脊椎动物（海绵）的主要群体之间的生态相互作用来实现。 此外，还将进行化学研究，以更透彻地了解南极半岛海绵对甲壳类中食动物的化学防御。三组问题将解决有关的重要性，中食动物，特别是片足类动物，在南极半岛西部的近岸栖息地。 首先，假设中草食动物是特别重的南极半岛海洋群落，并对藻类群落结构的重要影响将得到解决。 初步研究将记录哪些端足类动物全部或部分以微藻和大型藻类为食，占优势的大型藻类中丝状内生菌的发生率和分布，大型植物上端足类动物丰度的夜间模式比较，以及化学媒介在这些关系中的作用。 第二，广泛的假设，中食动物一般，特别是片足类动物，互动和捕食海绵在更大的程度上比迄今为止在南极社区承认将进行测试。 这些协会的功能基础将被认为是通过检查海绵是否被用作猎物，如果是这样，是否有证据表明，一些海绵产生的次级代谢产物，显示对中食动物，如片脚类动物的功效。 第三，研究人员将测试以下假设：1）南极藻类和无脊椎动物生物合成次级代谢产物，阻止端足类捕食者的进食; 2）在三种南极海绵中发现的色素是色氨酸catalase，用于防御影响蜕皮的甲壳类捕食者。 这些假设的评价将基于特定拒食代谢物的分离和表征，基于生物合成研究以确定色素的代谢来源，以及基于生物测定以确定两组化合物的化学防御作用。各种教育活动将是该项目的主要组成部分。将有机会支持研究生和本科生的研究，无论是通过NSF计划，以及家庭大学为基础的计划，包括一些资助的计划，提高少数民族在科学的代表性。通过他们经过验证和非常成功的互动网络计划，调查人员将继续让大量教师，K-12学生和其他社区成员参与他们在南极洲的科学工作。 此外，他们将积极参与外展工作，向学校和社区团体介绍他们的研究。

Mesoherbivores, and specifically amphipods, are a conspicuous and dominant component of the macroalgal community in Antarctica. Despite their high abundance, the functional ecology, and particularly the trophic relationships of Antarctic amphipods are poorly understood. This project will evaluate the importance of mesograzers (small invertebrate predators approximately 1 to 25 mm in body length) in western Antarctic Peninsula marine communities. This will be accomplished by examining the role of mesoherbivores in structuring macroalgal communities and by elucidating the ecological interactions of mesograzers with a dominant group of benthic macroinvertebrates, the marine sponges. Moreover, chemical studies will be conducted to gain a more thorough understanding of the chemical defenses that Antarctic Peninsula sponges direct towards crustacean mesograzers. Three sets of questions will be addressed concerning the importance of mesograzers, and amphipods in particular, in nearshore habitats of the western Antarctic Peninsula. First, the hypothesis that mesoherbivory is particularly heavy in western Antarctic Peninsula marine communities and has an important influence on algal community structure will be addressed. Initial studies will document which species of amphipods feed in whole or part on microalgae and macroalgae, the incidence and distribution of filamentous endophytes in dominant macroalgae, comparative night time patterns of amphipod abundances on macrophytes, and the role of chemical mediation in these relationships. Second, the broad hypothesis that mesograzers in general, and amphipods in particular, interact with and prey upon sponges to a greater extent than heretofore recognized in Antarctic communities will be tested. The functional basis of these associations will be considered by examining whether the sponges are used as prey, and if so, whether there is evidence that some sponges produce secondary metabolites that show efficacy against mesograzers such as amphipods. Third, the researchers will test the hypotheses that: 1) Antarctic algae and invertebrates biosynthesize secondary metabolites that deter feeding by amphipod predators; and 2) pigments found in three Antarctic sponges are tryptophan catabolites produced as defenses against crustacean predators that impact molting. Evaluation of these hypotheses will be based on isolation and characterization of the specific anti-feeding metabolites, on biosynthetic studies to establish the metabolic origin of the pigments, and on bioassays to establish the chemical defense roles of both groups of compounds. A variety of educational activities will be a major component of this project. Opportunities will be made to support graduate and undergraduate research, both through NSF programs as well as home university-based programs including a number of funded programs that enhance the representation of minorities in the sciences. Through their proven and highly successful interactive web program, the investigators will continue to involve a large numbers of teachers, K-12 students, and other members of the community at large in their scientific endeavors in Antarctica. Moreover, they will actively participate in outreach efforts by presenting numerous talks on their research to school and community groups.