Effects of ultraviolet radiation and water motion on the reef coral Porites compressa Dana: a flume experiment
Effects of ultraviolet radiation and water motion on the reef coral Porites compressa Dana: a flume experiment
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紫外线辐射和水运动对珊瑚滨珊瑚 (Porites compressa Dana) 的影响：水槽实验
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发表时间：
2001
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通讯作者：
I. B. Kuffner
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作者：
I. B. Kuffner
摘要 通过操作水槽实验探讨了水流和紫外线（UVR，280-400nm）对珊瑚滨珊瑚（Porites compressa Dana）的影响。本研究的目的是确定这种珊瑚是否通过调整紫外线吸收化合物（类菌孢素氨基酸，MAAs）的组织浓度来响应紫外线环境的变化，并观察这种适应是否受到水流的影响。此外，在实验过程中还测量了钙化率和叶绿素-a 浓度，以估计暴露于 UVR 和产生 MAA 的珊瑚-藻类共生的潜在成本（以生长减缓和/或光合能力降低的形式）。将来自单个雄性群落的 P. compressa 树枝暴露于室外连续流海水系统中的高流量或低流量（分别为 15cm s−1 和 3cm s−1）以及环境或无 UVR。叶绿素-a 和 MAA 浓度在暴露于实验条件下第 0、3 和 6 周后测定。两个三周期间浮力的增加用于计算钙化率。 UVR 的存在对 P. compressa 菌落中的总 MAA 浓度有显着的积极影响；然而，存在显着的相互作用。在暴露于 UVR 的菌落中，MAA 浓度在高水流中先增加然后降至初始水平，并在低水流中稳定增加。在未接受 UVR 的菌落中，MAA 浓度稳步下降，在 6 周内下降了 23%。缺乏 UVR 并不会导致叶绿素 a 浓度升高，但钙化率会受到 UVR 的轻微影响。这项研究支持了 MAA 在 P. compressa 中的光保护作用，并表明减轻环境 UVR 影响的成本是可以检测到的，但成本非常小。
Abstract The effects of water flow and ultraviolet radiation (UVR, 280–400 nm) on the reef coral Porites compressa Dana were explored in a manipulative flume experiment. The aim of this study was to determine whether this coral responds to changes in the UVR environment by adjusting the tissue concentration of UV-absorbing compounds (mycosporine-like amino acids, MAAs), and to see whether such an acclimation is affected by water flow. Also, calcification rate and chlorophyll-a concentration were measured during the experiment to estimate the potential costs (in the form of slowed growth and/or reduced photosynthetic capacity) to the coral–alga symbiosis of being exposed to UVR and producing MAAs. Branches of P. compressa from a single male colony were exposed to high or low flow (15 cm s−1 and 3 cm s−1, respectively) and ambient or no UVR in an outdoor, continuous-flow seawater system. Chlorophyll-a and MAA concentrations were determined after zero, 3 and 6 weeks of exposure to the experimental conditions. Increase in buoyant weight during the two 3-week periods was used to calculate calcification rate. The presence of UVR had a significant positive effect on total MAA concentration in the P. compressa colonies; however, there were significant interactions present. In colonies exposed to UVR, MAA concentration increased and then decreased to initial levels in high water flow, and increased steadily in low water flow. In colonies receiving no UVR, MAA concentration decreased steadily, declining 23% in 6 weeks. The absence of UVR did not result in higher chlorophyll-a concentrations, but the calcification rate was slightly affected by UVR. This study supports the putative photoprotective role of MAAs in P. compressa, and suggests that the costs of mitigating the effects of ambient UVR are detectable, but they are very small.