Collaborative Research: Hydrodynamic Forcing of Metabolism of Coral Reef Algal Communities (RUI)

合作研究：珊瑚礁藻类群落代谢的水动力强迫（RUI）

• 批准号: 9314470
• 负责人: Robert Carpenter
• 金额: $ 27.43万
• 依托单位: California State University-Northridge
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-02-15 至 1997-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9314470&HistoricalAwards=false
• 关键词: Collaborative; Research; Hydrodynamic; Forcing; Metabolism

Carpenter 9314470 The current paradigm explaining how coral reefs maintain high biomass of organisms and extremely high rates of gross primary productivity is that tight recycling of nutrients and organic matter occurs within the reef resulting in zones of net autotrophy alternating with zones of net heterotrophy. Autotrophic upstream communities are thought to support downstream heterotrophic assemblages with the overall balance resulting in ecosystem P/R ratios near unity. According to this paradigm, coral reefs are not coupled significantly to the surrounding oligotrophic ocean. Recent studies suggest that coral reefs may be much more dependent on hydrodynamic processes than currently believed. Although nutrient concentrations of tropical waters are very low, an enormous volume of water is advected across the reef and could result in a large flux of nutrients to benthic primary producers. The major upstream autotrophic zone is the reef flat where algal turf assemblages are responsible for the majority of primary productivity. Previous work has demonstrated that rates of primary productivity and nitrogen fixation of algal turf are affected significantly by water flow speed. Furthermore, flow measurements on one reef suggest that algal canopy height significantly alters the local hydrodynamic regime and as a result, metabolic processes of algal turfs may be diffusion-limited for a significant proportion of time. This project will test the hypothesis that rates of primary productivity and nitrogen fixation of coral reef algal turfs are diffusion-limited. Measurements of the flow environment on a reef flat will be made and used to estimate the degree to which algal turfs varying in canopy height are diffusion-limited. The project will then move on to test hypotheses about the specific factors that result in diffusion-limitation. The results of this project should fill a gap on empirical measurements of water flow in coral reef environments and how wate r flow affects algal metabolism. The results of this research may lead to a significant paradigm shift in understanding how coral reefs function. Demonstration that reefs are open ecosystems that are strongly coupled to the surrounding ocean environment would have important implications for predictions of the effects of global climate change on these unique ecosystems. ***

木匠9314470当前的范式解释了珊瑚礁如何保持生物群的高生物量和极高的一级生产率率极高的是，珊瑚礁内的紧密回收和有机物发生在礁石内，导致净自身植物的区域与净杂种杂物的区域交替。 人们认为自养上游社区支持下游异养分子组合，总体平衡导致生态系统P/R比接近统一。根据这种范式，珊瑚礁并未与周围的贫营养海洋显着耦合。 最近的研究表明，珊瑚礁可能比目前认为的更多依赖流体动力学过程。 尽管热带水的养分浓度非常低，但在整个珊瑚礁上占据了大量的水，并可能导致底栖初级生产者的大量营养物质。 上游主要的自养区是礁石公寓，藻类草皮组合负责大多数主要生产力。先前的工作表明，藻类草皮的一级生产率和氮固定率受水流速度的显着影响。此外，一个珊瑚礁上的流量测量表明，藻类冠层高度显着改变了局部流体动力学状态，因此，在很大一部分时间内，可以将藻类草皮的代谢过程扩散。 该项目将检验以下假设：珊瑚礁藻草皮的一级生产率和氮固定速率是扩散限制的。 将对礁平平的流动环境进行测量，并用于估计藻类草皮在冠层高度变化的程度是扩散限制的。然后，该项目将继续测试有关导致扩散限制的特定因素的假设。 该项目的结果应填补珊瑚礁环境中水流的经验测量以及WATE R流动如何影响藻类代谢的空白。 这项研究的结果可能会导致理解珊瑚礁的功能的显着范式转移。 证明珊瑚礁是与周围海洋环境密切相结合的开放生态系统，将对预测全球气候变化对这些独特生态系统的影响的预测具有重要意义。 ***