Kerlin Jamie R, Barnas Danielle M, Silbiger Nyssa J
Department of Biology, California State University, Northridge, CA, 91330, USA.
Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kaneohe, HI, 96744, USA.
Oecologia. 2025 Jan 15;207(1):21. doi: 10.1007/s00442-024-05660-6.
Land-based inputs, such as runoff, rivers, and submarine groundwater, can alter biologic processes on coral reefs. While the abiotic factors associated with land-based inputs have strong effects on corals, corals are also affected by biotic interactions, including other neighboring corals. The biologic responses of corals to changing environmental conditions and their neighbors are likely interactive; however, few studies address both biotic and abiotic interactions in concert. In a manipulative field experiment, we tested how the natural environmental gradient created by submarine groundwater discharge (SGD) affected holobiont and symbiont metabolic rates and endosymbiont physiology of Porites rus. We further tested how the effect of SGD on the coral was mediated by intra and interspecific interactions. SGD is a natural land-sea connection that delivers nutrients, inorganic carbon, and other solutes to coastal ecosystems worldwide. Our results show that a natural gradient of nutrient enrichment and pH variability as a result of acute SGD exposure generally benefited P. rus, increasing gross photosynthesis, respiration, endosymbiont densities, and chlorophyll a content. Conspecifics in direct contact with the a neighboring coral, however, altered the relationship between coral physiology and SGD, lowering the photosynthetic and respiration rates from expected values when the coral had no neighbor. We show that the response of corals to environmental change is dependent on the types of nearby neighbor corals and how neighbors alter the chemical or physical environment around the coral. Our study underscores the importance of considering biotic interactions when predicting the physiologic responses of corals to the environment.
陆基输入，如径流、河流和海底地下水，会改变珊瑚礁上的生物过程。虽然与陆基输入相关的非生物因素对珊瑚有强烈影响，但珊瑚也受到生物相互作用的影响，包括其他相邻珊瑚。珊瑚对不断变化的环境条件及其邻居的生物反应可能是相互作用的；然而，很少有研究同时涉及生物和非生物相互作用。在一项操纵性野外实验中，我们测试了由海底地下水排放（SGD）产生的自然环境梯度如何影响多孔鹿角珊瑚的全生物和共生体代谢率以及内共生体生理学。我们进一步测试了SGD对珊瑚的影响是如何通过种内和种间相互作用介导的。SGD是一种自然的陆海连接，它为全球沿海生态系统输送营养物质、无机碳和其他溶质。我们的结果表明，由于急性SGD暴露导致的营养物质富集和pH值变化的自然梯度总体上有利于多孔鹿角珊瑚，增加了总光合作用、呼吸作用、内共生体密度和叶绿素a含量。然而，与相邻珊瑚直接接触的同种珊瑚改变了珊瑚生理学与SGD之间的关系，当珊瑚没有邻居时，光合和呼吸速率低于预期值。我们表明，珊瑚对环境变化的反应取决于附近相邻珊瑚的类型以及邻居如何改变珊瑚周围的化学或物理环境。我们的研究强调了在预测珊瑚对环境的生理反应时考虑生物相互作用的重要性。
