Department of Biology, San Diego State University, San Diego, California, United States of America.
PLoS One. 2009 Nov 26;4(11):e8043. doi: 10.1371/journal.pone.0008043.
Space limitation leads to competition between benthic, sessile organisms on coral reefs. As a primary example, reef-building corals are in direct contact with each other and many different species and functional groups of algae. Here we characterize interactions between three coral genera and three algal functional groups using a combination of hyperspectral imaging and oxygen microprofiling. We also performed in situ interaction transects to quantify the relative occurrence of these interaction on coral reefs. These studies were conducted in the Southern Line Islands, home to some of the most remote and near-pristine reefs in the world. Our goal was to determine if different types of coral-coral and coral-algal interactions were characterized by unique fine-scale physiological signatures. This is the first report using hyperspectral imaging for characterization of marine benthic organisms at the micron scale and proved to be a valuable tool for discriminating among different photosynthetic organisms. Consistent patterns emerged in physiology across different types of competitive interactions. In cases where corals were in direct contact with turf or macroalgae, there was a zone of hypoxia and altered pigmentation on the coral. In contrast, interaction zones between corals and crustose coralline algae (CCA) were not hypoxic and the coral tissue was consistent across the colony. Our results suggest that at least two main characteristic coral interaction phenotypes exist: 1) hypoxia and coral tissue disruption, seen with interactions between corals and fleshy turf and/or some species of macroalgae, and 2) no hypoxia or tissue disruption, seen with interactions between corals and some species of CCA. Hyperspectral imaging in combination with oxygen profiling provided useful information on competitive interactions between benthic reef organisms, and demonstrated that some turf and fleshy macroalgae can be a constant source of stress for corals, while CCA are not.
空间限制导致珊瑚礁上底栖、固着生物之间的竞争。作为一个主要的例子，造礁珊瑚与彼此以及许多不同种类和功能群的藻类直接接触。在这里，我们使用高光谱成像和氧气微 profiling 组合来描述三种珊瑚属和三种藻类功能群之间的相互作用。我们还进行了原位相互作用横断面，以量化这些相互作用在珊瑚礁上的相对发生情况。这些研究是在南莱恩群岛进行的，这里是世界上一些最偏远和近乎原始的珊瑚礁的所在地。我们的目标是确定不同类型的珊瑚-珊瑚和珊瑚-藻类相互作用是否具有独特的微观生理特征。这是第一个使用高光谱成像来描述海洋底栖生物在微米尺度上的特征的报告，并且被证明是一种区分不同光合作用生物的有价值的工具。在不同类型的竞争相互作用中，生理学上出现了一致的模式。在珊瑚与草皮或大型藻类直接接触的情况下，珊瑚上会出现缺氧区和色素改变。相比之下，珊瑚与皮层状珊瑚藻（CCA）之间的相互作用区不缺氧，珊瑚组织在整个群体中是一致的。我们的结果表明，至少存在两种主要的特征珊瑚相互作用表型：1）缺氧和珊瑚组织破坏，见于珊瑚与肉质草皮和/或某些大型藻类之间的相互作用，2）无缺氧或组织破坏，见于珊瑚与某些 CCA 之间的相互作用。高光谱成像与氧气剖面相结合，为底栖珊瑚礁生物之间的竞争相互作用提供了有用的信息，并表明一些草皮和肉质大型藻类可能是珊瑚的持续应激源，而 CCA 则不是。
