The layer of water under landfast ice has unique oceanographic characteristics, as described in this review of recent assessment information for the central Alaskan Beaufort Sea coast. Water circulation is very slow, usually near the lower threshold of current meters. Barometric storms cause infrequent surges of water. The weak thermohaline-driven circulation is the reverse of that in ice-free estuaries. Watertemperatures are always close to the slowly declining freezing point, and salinity gradually increases to high levels in bays because of flushing times of a month or more. Biological processes during the dark third of the year when there is no photosynthesis are dependent primarily on detritus and stored energy. Detritus is decomposed slowly by bacteria, and consumed by epibenthic invertebrates. Invertebrates and their main predators, fish, both reproduce under the ice cover. Food may limit biological activity in late winter, even in nearshore areas. Spring under-ice primary production totals possibly one-third of annual production with production of epontic algae attached to the bottom surface of the ice equalling only 5% of annual production. During breakup, river floods quickly flush under-ice areas; nearshore salinity drops to zero, and the wintertime thermohaline circulation is reversed. Year-to-year physical variations in the habitat cause the populations of three resident animals to vary up to sevenfold, but there are no regular cycles in abundance. Knowledge of these under-ice characteristics is important for understanding the Beaufort Sea coastal ecosystems, even for the relatively short open-water period.

The heavy metals chromium, zinc, cadmium and lead have accumulated in the sediments around some offshore oil rigs. Oil production is now being considered for some nearshore sections of the Beaufort Sea coast. During winter in the Beaufort Sea, heavy metals in the sediments will not be dispersed; the under-ice currents are slow, and some of the bottom is covered by very saline, relatively stagnant water. Heavy metals in the sediments can probably be assimilated by epibenthic animals in the nearshore region, and then transferred through the food chain to natives who partially subsist on marine animals.

With 4 Text-figures and 1 Table DA vm (1963, 1965) described a large neuston sampler based on the principle of the otter-board and has reviewed earlier neuston sampling devices. See also CASSIE (1963) and BANSE (1964) for a discussion of other neuston sampling devices, methods and theory. DAviD has used his sampler successfully from the R.R.S. Discovery at speeds up to six knots. RICHARDS and SuND of the U.S. Fish and Wildlife Service (personal communication) have modified DA vm's net with larger runners and vanes and have towed it at speeds up to nine knots to catch small fish and squids in the surface layer. During Cruise 7 of the R/S Te Vega of Stanford University, we had an opportunity to study the neuston of the western equatorial Pacific. Because much of our work in lagoons and bays was done from small boats, we built a small neuston sampler. Its chief advantages are: 1. The net is carried well forward of the otter-board platform so that there is little if any disturbance of the water in front of the net. 2. The net tows well outside the wake of the towing boat or ship. 3. The depth of fishing can be quickly adjusted for studies of micro-vertical distribution. 4. The net has a flow meter so that both volume of water filtered and sea surface skimmed can be calculated. 5. The sampler is inexpensive and can be handled by one person in a small boat.

No abstract

In 1987, slope-protection fabric was removed from the top of an artificial gravel island in Harrison Bay, southwestern Beaufort Sea.As a result, currents began to erode the island's top. After it is eroded to a subsurface shoal, ice keels will slowly gouge and disrupt the remaining shoal. This paper analyzes the ice-gouge process and estimates the rate of sediment disruption by gouges. The rate is derived from existing information on gouges in the surrounding seafloor in Harrison Bay and for a time when the shoal is at half of the water depth (-7.5 m).It is estimated that ice keels will typically disrupt 1 vertical meter of the whole surface of the shoal within a period of about 2 decades.