Geographical Variation in the Effects of Brown Algal Secondary Metabolites on Temperate Marine Herbivores

这项研究建立在以前的发现基础上，即东北和西南太平洋温带地区类似海带的植物产生的次生代谢物在质量和数量上存在差异。这项研究的目的是：1)进一步记录加州和新西兰大型褐藻中次生化学物质的水平和种类的差异，以及2)确定选定的海洋食草性无脊椎动物对这些化合物的行为和长期反应。将从这两个地区进行广泛的收集，以记录常见褐藻物种之间、物种内个体和组织之间以及分离植物中多酚和亲脂化合物浓度的变化。将通过测量消耗率的变化来测试来自这两个地区的普通海胆和蜗牛的摄食偏好，以测试这些次级化合物的影响。次生代谢物对各种以植物为食的无脊椎动物的生理影响将通过测量吸收效率、生长速度和性腺发育来评估，其中次生代谢物的种类和水平不同。假设在这些地区，藻类和食用藻类的动物之间的相互作用将在两个重要方面有所不同：1)新西兰藻类的化学防御能力将比加州物种的数量和多样性更大；2)新西兰的食藻动物将比来自加州的同类食藻无脊椎动物更能耐受多酚。总体而言，据预测，从温带岩石海岸的主要初级生产者藻类向消耗它们的无脊椎动物转移能量的机制在生物地理尺度上会有很大差异。

This research builds on previous findings that qualitative and quantitative differences exist in the secondary metabolites produced by kelp-like plants between the temperate northeast and southwest Pacific regions. The purpose of the research is to: 1) further document variation in the levels and kinds of secondary chemicals among large brown algae from California and New Zealand, and 2) determine behavioral and long term responses of selected marine plant-eating invertebrates to these compounds. Extensive collections will be made from both areas to document variation in concentrations of polyphenolic and lipophilic compounds among the common brown algal species; among individuals and tissues within species; and through time in detached plants. Feeding preferences of common sea urchins and snails from both regions will be tested for the effects of these secondary compounds by measuring variation in consumption rate. Physiological influences of secondary metabolites on various plant-eating invertebrates will be evaluated by measuring absorption efficiencies, growth rates, and gonadal development among experimental treatments in which the kinds and levels of secondary metabolites are varied. Hypothetically interactions between algae and the animals which consume them will differ among these regions in two important ways: 1) the amount and diversity of chemical defenses in New Zealand algae will be greater than in California species; and 2) the algae eaters in New Zealand will be more tolerant of polyphenolics than will similar algal consuming invertebrates from California. Overall, the mechanisms which mediate transfer of energy from the algae which are the dominant primary producers on temperate rocky shores to the invertebrates which consume them are predicted to vary greatly on a biogeographical scale.