Geologic Interpretation of the Acoustic Data Collected During National Oceanic and Atmospheric Administration (NOAA) Survey H11252 (H11252_INTERP.SHP, Geographic)

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 geologic interpretation of the acoustic data from survey H11252 in Geographic 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）与美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration）以及康涅狄格州环境保护部（Connecticut Department of Environmental Protection）合作，针对长岛海湾（Long Island Sound）——这片坐落于美国人口最稠密区域的东海岸大型河口湾——绘制了详细的海底地质图。这些研究依托1982年启动的康涅狄格州合作研究项目展开。本研究项目的当前阶段旨在开展海底沉积物分布、调控沉积物分布的过程、近岸环境问题，以及底栖生物群落结构（benthic community structures）与海底地质间关联的相关研究。

人为废弃物、有毒化学品，以及住宅、商业与休闲开发引发的土地利用模式变化，已对该海湾的环境造成压力，导致底栖生境（benthic habitat）退化乃至潜在丧失（Koppelman等，1976；长岛海湾研究，1994）。详细的海底地图有助于评估不利影响的范围，并为未来的资源合理管理提供支撑。因此，为持续深化对长岛海湾的认知，我们针对特定重点区域构建并解译了多波束测深数据（multibeam bathymetric data）。本文所呈现的H11252号勘测声学数据的地质解译，覆盖了长岛海湾东部六英里礁以西约64平方公里的海底区域。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”勘测船开展海图测绘作业时获取。该船船体搭载的Simrad EM1002多波束系统，用于采集研究区深水区（水深>20米）的勘测航线数据。此外，两艘搭载船体安装Reson系统的29英尺小艇从母船出发，用于采集浅水区的勘测航线数据。

详细的测深数据及其解译成果具备多重用途：(1) 明确海底的地质异质性——这是调控底栖生境多样性的核心控制因素之一；(2) 深化对控制海底沉积物分布与输运、底栖生境及相关底内生物群落（infaunal community structures）结构分布的过程的认知；(3) 为未来的研究、监测与管理活动提供详细的框架支撑。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择与单点测量结果的准确解译至关重要。