Freeman Christopher J, Easson Cole G
Smithsonian Marine Station, Fort Pierce, FL, USA; IRCP, Institute for Pacific Coral Reefs, Labex Corail, Papetoai, Moorea, French Polynesia.
Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Dania Beach, FL, United States; Department of Biology, University of Alabama at Birmingham, Birmingham, AL, USA.
PeerJ. 2016 Mar 17;4:e1816. doi: 10.7717/peerj.1816. eCollection 2016.
Photosymbionts play an important role in the ecology and evolution of diverse host species within the marine environment. Although sponge-photosymbiont interactions have been well described from geographically disparate sites worldwide, our understanding of these interactions from shallow water systems within French Polynesia is limited. We surveyed diverse habitats around the north coast of Moorea, French Polynesia and screened sponges for the presence of photosymbionts. Overall sponge abundance and diversity were low, with <1% cover and only eight putative species identified by 28S barcoding from surveys at 21 sites. Of these eight species, seven were found predominately in shaded or semi-cryptic habitats under overhangs or within caverns. Lendenfeldia chondrodes was the only species that supported a high abundance of photosymbionts and was also the only species found in exposed, illuminated habitats. Interestingly, L. chondrodes was found at three distinct sites, with a massive, fan-shaped growth form at two of the lagoon sites and a thin, encrusting growth form within a bay site. These two growth forms differed in their photosymbiont abundance, with massive individuals of L. chondrodes having higher photosymbiont abundance than encrusting individuals from the bay. We present evidence that some sponges from French Polynesia support abundant photosymbiont communities and provide initial support for the role of these communities in host ecology.
光合共生体在海洋环境中多种宿主物种的生态和进化过程中发挥着重要作用。尽管全球各地地理位置不同的区域均对海绵 - 光合共生体之间的相互作用进行了详尽描述，但我们对法属波利尼西亚浅水区系统中这些相互作用的了解仍较为有限。我们对法属波利尼西亚莫雷阿岛北海岸周围的多样栖息地进行了调查，并对海绵是否存在光合共生体进行了筛选。总体而言，海绵的丰度和多样性较低，在21个地点的调查中，覆盖率<1%，通过28S条形码鉴定仅识别出8个假定物种。在这8个物种中，有7种主要发现于悬垂物下方或洞穴内的阴凉或半隐蔽栖息地。软骨海绵是唯一支持大量光合共生体的物种，也是在暴露的光照栖息地中发现的唯一物种。有趣的是，在三个不同地点发现了软骨海绵，其中两个泻湖地点的呈块状扇形生长形态，一个海湾地点的呈薄的覆盖状生长形态。这两种生长形态的光合共生体丰度有所不同，块状的软骨海绵个体比海湾中覆盖状个体的光合共生体丰度更高。我们提供的证据表明，法属波利尼西亚的一些海绵支持丰富的光合共生体群落，并为这些群落在宿主生态中的作用提供了初步支持。
