Interpreting long-term changes in benthic community structure: a new protocol
Interpreting long-term changes in benthic community structure: a new protocol
复制标题
解释底栖群落结构的长期变化：新协议
作者：
D. Rhoads;J. Germano
记录海底生态系统的长期变化对于评估和管理这种变化对以下方面的影响十分重要：1）次级生产，特别是导致商业上重要的食物网，2）食物网内的污染物转移，3）“新”组合代谢烧掉不稳定碎屑的能力，否则这些碎屑可能积累，导致长期缺氧，（4）营养物质从海底回流到初级生产者。伴随着底栖扰动的生物-沉积物关系具有可预测的特征。虽然参与的物种可能因区域或季节而异，但它们的生活史属性和与相关沉积物的功能关系似乎具有普遍性。先锋系列是近地表栖息的、多产的，并且很容易被底层捕食者利用。然而，这些类群可能是潜在的污染物载体。密集的管垫可以促进高BOD有机物的沉积和保留。晚期演替阶段系列以生物扰动的“头向下”存款馈线为代表。这些物种的深层隐蔽的底栖动物栖息地可能使它们不太重要的猎物表底动物的捕食者。由这些平衡组合构成的沉积物的特点是不稳定有机质、沉积硫化物和需氧量低。沉积物孔隙水的生物灌溉将营养物质（N、P、Si）返还给初级生产者。绘制演替镶嵌图对于记录底栖生物群落结构和相关生物过程的重大长期变化非常重要。我们的绘图工具包括一个船舶部署的沉积物剖面相机，生物沉积物的关系，可以在现场成像与此仪器。这种映射协议并不打算取代传统的采样。相反，演替地图被用来有效地检测系统中的变化，设计一个具有成本效益的采样网格，以获得地球化学和生物地面实况样本，并构建关于变化如何回答四个概述的管理问题的假设。
Documentation of long-term change in benthic ecosystems is important for assessing and managing the effects of such change on: 1) secondary production, particularly leading to commercially important food webs, 2) pollutant transfer within the food web, 3) the ability of the ‘new’ assemblage to metabolically burn-off labile detritus that might otherwise accumulate, contributing to long-term hypoxia, and 4) recyling of nutrients from the seafloor back to primary producers.Organism-sediment relationships which accompany benthic disturbances have predictable features. Although participating species may vary regionally or seasonally, their life-history attributes and functional relationships to the associated sediment appear to be universal. Pioneering seres are near-surface dwelling, productive, and are readily available to demersal predators. However, these taxa may be potential pollutant vectors. Dense tube mats may promote the deposition and retention of high BOD organic matter. Late successional stage seres are represented by deeply bioturbating ‘head-down’ deposit feeders. The deep cryptic infaunal habitat of these species may make them less important as prey for epifaunal predators. Sediments populated by these equilibrium assemblages are characteristically low in labile organic matter, sedimentary sulphides, and oxygen demand. Nutrients (N, P, Si) are returned to primary producers by biogenic irrigation of sediment pore water.Mapping of successional mosaics is important for documenting major long-term change in benthic community structure and associated biogenic processes. Our mapping tool consists of a vessel-deployed sediment-profile camera; organism-sediment relationships can be imaged in situ with this instrument. Such a mapping protocol is not intended to replace traditional sampling. Rather, the successional maps are used to efficiently detect change in a system, design a cost-efficient sampling grid for obtaining geochemical and biological ground-truth samples, and to construct hypotheses about how the change might answer the four outlined management questions.