During the summer of 1963 and the spring of 1965, a study was made comparing the subtidal sediment salinities with those of the immediately overlying water in a small estuary north of Woods Hole, the Pocasset River, and relating these findings to the distribution of the estuarine fauna. The estuary is a fluctuating type with a nearly constant river flow. At each location, there are pronounced though precise fluctuations of the water salinity with tidal periodicity. Bottom waters show periods of highly saline, essentially marine water and periods of nearly freshwater, separated by abrupt and brief transitional periods throughout the upper half of the estuary. The low salinity phase is longer at the upper end of the estuary and the high salinity phase gradually predominates as one proceeds seaward. In contrast to the marked fluctuation in bottom salinity, the salinities in the sediments are stable and constant, with each station having its own characteristic salinity that gradually increases from the uppermost reaches to the mouth. This salinity regime has a marked effect on the distribution of the benthic fauna. The epifauna, subjected to the extreme salinity fluctuation and rapid and extreme salinity changes, is poorly represented, particularly in the upper part of the estuary. The infauna, living under much more stable salinity conditions, make up the vast majority of the fauna. The periodic short‐term fluctuations in the water salinity stabilize the sediment salinities and subject the infauna to less physiological stress than that imposed on the epifauna. A brackish water fauna dominates the uppermost part of the estuary. The fauna is transitional in a zone where the sediment salinities vary from 19 to 22%. At higher sediment salinity values, lower in the estuary, the marine element predominates. Animals collected from the transitional zone were exposed in the laboratory to low and high salinity water obtained from the same locality at low and high tide, respectively, and to a control salinity duplicating the average sediment salinity of the zone. There were four patterns of response: 1) stress symptoms and death usually in less than 24 hr; 2) stress symptoms and recovery; 3) behavioral response; and 4) normal, identical activity in the low, high, and control salinity water. These responses were related to the depth distribution patterns of the species, sediment salinities, and redox potential values at the collecting site.

No abstract

On October 9, 1974 the oil barge Bouchard 65 loaded with 73 000 barrels of oil spilled what was initially thought by the Coast Guard to be a few barrels and later raised to an undetermined amount of No. 2 fuel oil off the west entrance of the Cape Cod Canal in Buzzards Bay, Massachusetts (anchor site C, Fig. 1). Within the following 2-wk period, oil from the barge was found contained along the west side of Bassett's Island and inner Red Brook Harbor, a distance of 5.0 km from the site of the spillage. Qualitative samples of dead and moribund marine invertebrates were collected in tide pools and slight depressions along the beaches. A collection consisting of 4360 invertebrates comprising 105 species, plus 2 species of fish were found in 8 samples. Noticeable effects of the oil on the salt-marsh plant community were also observed. A detailed quantitative examination was begun to determine the effects of the oil on various components of the affected salt-marsh community in Winsor Cove compared to a selected control site. From data collected in September 1977, the marsh grass in the lower intertidal zone in Winsor Cove has shown an inability to reestablish itself by either reseeding or rhizome growth. The associated sediments show a correspondingly high concentration of petroleum hydrocarbons impregnated in the peat substrate. Erosion rates measured in the affected area, as a result of the 3-yr period of marsh degeneration, were 24 times greater than the control site. Microscopic algae were collected during the sampling period and those present were considered least sensitive to environmental changes. Examination of the interstitial fauna found in the study area in the summer of 1977 showed an extremely reduced number of individuals and species. Key words: salt marsh, No. 2 fuel oil, petroleum, erosion, pollution, algae, marsh grass, interstitial fauna, marine invertebrates

No abstract

A very extensive bibliography of papers on underwater explosions and their effects on marine lifè .has been collected and summarized. When exposed to blast effects, vertebrates with swim bladders or lungs that contain gas are at least an order of magnitude more sensitive than other life. Regression analysis of several different experiments on explosive damage to fish has been combined with reports of fish concentrations and explosives used in oil well severance in order to estimate the probable extent of damge to fish populations from a limited number of severance explosions. Damage per explosion should not be significant and is probably considerably less than that caused by a one hour tow of a bottom trawl net.