Color Hill-Shaded GeoTIFF Image Showing the 2-m bathymetry Generated from National Oceanic and Atmospheric Administration (NOAA) Survey H11252 in Eastern Long Island Sound (H11252_2MUTM18_MB.TIF, UTM Zone 18)

The U.S. Geological Survey, in cooperation with the National Oceanic and Atmospheric Administration and the Connecticut Department of Environmental Protection, has produced detailed geologic maps of the sea floor in Long Island Sound, a major East Coast estuary surrounded by the most densely populated region of the United States. These studies have built upon cooperative research with the State of Connecticut that was initiated in 1982. The current phase of this research program is directed toward studies of sea-floor sediment distribution, processes that control sediment distribution, nearshore environmental concerns, and the relation of benthic community structures to the sea-floor geology.
Anthropogenic wastes, toxic chemicals, and changes in land-use patterns resulting from residential, commercial, and recreational development have stressed the environment of the Sound, causing degradation and potential loss of benthic habitats (Koppelman and others, 1976; Long Island Sound Study, 1994). Detailed maps of the sea floor are needed to help evaluate the extent of adverse impacts and to help manage resources wisely in the future. Therefore, in a continuing effort to better understand Long Island Sound, we have constructed and interpreted multibeam bathymetric data within specific areas of special interest. The color GeoTIFF of hill-shaded bathymetry in UTM Zone 18 projection presented herein covers a roughly 64 km square area of the sea floor in the area just west of Six Mile Reef, eastern Long Island Sound. The original multibeam bathymetric data were collected during 2004 as part of charting applications aboard the NOAA Survey Vessel Thomas Jefferson. A Simrad EM1002 multibeam system mounted on the hull of this vessel was used to acquire data along survey lines from the deeper water (>20 m) parts of the study area. Two 29-foot launches with hull-mounted Reson systems were deployed from the ship and were used to acquire data along survey lines from the shallower areas.
Detailed bathymetric data and their interpretations serve many purposes, including: (1) defining the geological variability of the sea floor, which is one of the primary controls of benthic habitat diversity; (2) improving our understanding of the processes that control the distribution and transport of bottom sediments and the distribution of benthic habitats and associated infaunal community structures; and (3) providing a detailed framework for future research, monitoring, and management activities. The bathymetric data models also serve as base maps for subsequent sedimentological, geochemical, and biological observations, because precise information on environmental setting is important for selection of sampling sites and for accurate interpretation of point measurements.

美国地质调查局（U.S. Geological Survey）联合美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration）与康涅狄格州环境保护部，完成了长岛海峡海底的详细地质填图工作。长岛海峡作为美国东海岸的重要河口湾，周边环绕着美国人口最密集的区域。此项研究依托1982年启动的康涅狄格州合作研究项目推进。当前该研究计划的阶段目标聚焦于：海底沉积物分布特征、调控沉积物分布的动力过程、近岸环境关切问题，以及底栖生物群落结构与海底地质的关联关系。
人类活动废弃物、有毒化学品，以及住宅、商业和休闲开发引发的土地利用模式变化，已对长岛海峡的生态环境造成胁迫，导致底栖生境退化乃至潜在丧失（Koppelman等，1976；长岛海峡研究计划，1994）。精准的海底填图数据，既有助于评估负面影响的波及范围，也可为未来的资源科学管理提供支撑。因此，为进一步深化对长岛海峡的认知，研究团队针对特定重点区域开展了多波束测深数据的采集与解译工作。本文展示的通用横轴墨卡托投影（Universal Transverse Mercator，UTM）第18投影带下的晕渲地形彩色GeoTIFF影像，覆盖了长岛海峡东部六英里礁西侧约64平方千米的海底区域。原始多波束测深数据采集于2004年，由美国国家海洋和大气管理局"托马斯·杰斐逊"号测量船在执行海图测绘任务期间获取。该船搭载的Simrad EM1002多波束系统，用于采集研究区深水区（水深>20米）的测线数据。此外，研究团队还使用两艘搭载Reson测深系统的29英尺小艇，从研究区浅水区采集测线数据。
高精度的测深数据及其解译成果具备多重应用价值：其一，可用于刻画海底地质异质性——这是调控底栖生境多样性的核心控制因素之一；其二，有助于深化对控制海底沉积物分布与输运、底栖生境及相关内栖生物群落结构分布的动力过程的认知；其三，可为后续的研究、监测与管理活动提供精细化的基础框架。此外，测深数据模型还可作为后续沉积学、地球化学与生物学观测的底图，因为环境背景的精准信息对于采样点位选取和点位实测数据的准确解译至关重要。