The New England Offshore Mining Environmental Study

Abstract

INTRODUCTION Interest in the economic recovery of minerals from beneath the sea has accelerated in the past few years as demands for raw materials have increased. Only recently, however, has there been a clear realization that offshore mining must not be permitted to jeopardize the quality of the marine environment. All too often we have failed to anticipate the unforeseen, and often long-range, consequences of technology developed to improve our quality of life. Before we consider the sea floor as a new source for materials, we must carefully weight the implications of such development on the capacity of the marine environment to provide its many services to mankind. The National Oceanic and Atmospheric Administration (NOAA) believes that understanding the environmental consequences of marine mining is a logical objective of Federal research. The New England Offshore Mining Environmental Study (NOMES) is a major step toward understanding the factors governing the impact of offshore sand and gravel mining and toward developing the capability to predict the extent of environmental disturbance that may result from this enterprise. The area for the proposed experiment is located 16 kilometers east of the Boston, Massachusetts, harbor entrance, 2.8 kilometers west of the Boston Lightship and 8.9 kilometers northeast of the northern end of Nantasket Beach, closest point to the mainland. Dredging will be confined to an irregularly oblong area, approximately 1.5 kilometers long and .6 kilometers wide trending N200W and centered at 42°20'4l"N, 70° 47"10Il W. A dumping area used to displose of local harbor and river dredge spoil is located 1.2 kilometers east of the dredge site. Chemical analyses of the sediment cores from the site will assist in evaluating to what extent the region has been affected by these activities. CONCEPT AND APPROACH Developing the capability to predict the ecological effects of marine sand and gravel mining is the central objective of NOMES. In determining the probable environmental impact of mining at a study site off the coast of Massachusetts, techniques and data requirements would be developed to permit valid determinations in varied physical and biological settings. If the problem posed by this experiment were solely one of assessing, after the fact, the impact of a particular mining operation, the approach might be considerably simplified. However, the need to develop a general predictive capability introduces particular complexities that influenced the selection of the experimental approach described below. The factors that determine the ecological impact of sand and gravel mining can be generalized as follows:the effects on metabolism and survival of organisms confronted with high suspensions of fine particulate matter.the effects on the benthic habitat caused by sediment removal and redepositions.the chemical and physical response of resuspended bottom deposits.the manner in which chemical constituents are transferred or amplified by organisms through the marine food web.