Dynamic Nature of Algal Symbioses: Consequences for Host Fitness in an Intertidal Alga-Anemone Association.

细纹海葵是东北太平洋潮间带群落中最丰富的海葵。这种优势无脊椎动物在这些系统的生态学中起着重要作用。由于a . elegantissima与两种不同的光合藻类具有独特的共生关系，因此它作为一个模型也很重要，可以帮助我们更好地理解共生伙伴关系以及它们如何应对不断变化的环境。这两种藻类在华盛顿州外海岸的A. elegantissima种群中的相对丰度将被评估。这将为气候变化提供晴雨表；据预测，如果温度或光照水平发生变化，这两种共生物种的分布和丰度就会发生变化。这一预测是基于共生藻类不同的生理耐受性（一种更喜欢凉爽、低光的环境，而另一种更适合温暖、高光的环境）。在实验室研究中，每个共生体的相对价值将通过测量它们对海葵宿主生长和繁殖的影响来测试。海葵将暴露在不同程度的自然阳光下，有性繁殖、无性分裂和身体生长将被监测。共生体的健康状况也将根据光合生产力和分裂率来衡量。这项工作的结果将为了解一种重要而丰富的潮间带物种的生态学提供有价值的见解。研究结果对于发展可测试的假设也很重要，这些假设是关于具有多个共生伙伴的其他长寿物种（例如地衣和珊瑚）将如何受到与气候变化相关的共生补体变化的影响。该项目将涉及共生研究，包括14名本科生和2名研究生，其中包括科学界代表性不足的群体成员。该项目的要素将纳入现有的本科课程和小学外展计划，并通过公开讲座传播。

Anthopleura elegantissima is the most abundant sea anemone in intertidal communities of the northeast Pacific Ocean. This dominant invertebrate plays an important role in the ecology of these systems. Because of the unique symbiotic relationship A. elegantissima has with two distinct photosynthetic algae, it is also important as a model to help us better understand symbiotic partnerships and how they respond to a changing environment. The relative abundance of the two algae in A. elegantissima populations along the outer coast of Washington State will be assessed. This will provide a barometer for climate change; the distributions and abundances of the two symbiont species are predicted to shift if, for example, temperature or light levels change. This prediction is based on the different physiological tolerances of the algal symbionts (one prefers cooler, low-light environments while the other does better in warmer, high-light environments). In laboratory studies, the relative value of each symbiont will be tested by measuring their impact on growth and reproduction of the anemone host. Anemones will be exposed to different levels of natural sunlight, and sexual reproduction, asexual division, and body growth will be monitored. Health of the symbionts will also be measured in terms of photosynthetic productivity and division rate. Results of the work will provide valuable insights into the ecology of an important and abundant intertidal species. Results will also be important for developing testable hypotheses about how other long-lived species with multiple symbiotic partners (e.g., lichens and corals) will be affected by climate change-related shifts in symbiont complements. This project will engage in symbiosis research 14 undergraduate and 2 graduate students, including members of groups underrepresented in science. Elements of the project will be incorporated into existing undergraduate courses and an elementary school outreach program, and also disseminated through public lectures.