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At least 955 records · Page 53Linked to original sources
USGS1973

Chemical composition of a saline lake on Enderbury Island, Phoenix Island Group, Pacific Ocean

Ion activity products for the dissolution of calcite, aragonite, gypsum, monetite, brushite, dolomite, magnesite, hydroxyapatite, and fluorapatite were calculated for a South Pacific guano island brine with an ionic strength of 6.4. Environmental conditions for the brine at the time of analysis and of sampling indicated saturation with respect to calcite, aragonite, gypsum, hydroxyapatite and fluorapatite; a comparison of the ion activity products and equilibrium constants indicated saturation or supersaturation with respect to most minerals found in lake sediments or elsewhere on the island. The results suggest that chemical thermodynamic calculations for brines may have some usefulness despite the many assumptions and estimations that must be made.

Journal of Research of the U.S. Geological Survey↗
USGS1991

The distribution of seabirds and fish in relation to ocean currents in the southeastern Chukchi Sea

In late August 1988, we studied the distribution of seabirds in the southeastern Chukchi Sea, particularly in waters near a major seabird colony at Cape Thompson. Foraging areas were characterized using hydrographic data obtained from hydroacoustic surveys for fish. Murres ( Uria spp. ) and Black-legged Kitttiwakes Rissa tridactyla breeding at Cape Thompson fed mostly on Arctic cod, which are known from previous studies to be the most abundant pelagic fish in the region. Our hydroacoustic surveys revealed that pelagic fish were distributed widely, but densities were estimated to be low (e.g., 0.1-10 g∙m -3 ) throughout the study area and a few schools were recorded. Large feeding flocks of murres and kittiwakes were observed over fish schools with densities estimated to exceed 15 g∙m -3 . Fish densities were higher in shallow Alaska Coastal Current waters than offshore in Bering Sea waters, and most piscivorous seabirds foraged in coastal waters. Poor kittiwake breeding success and a low frequency of fish in murre and kittiwake stomachs in late August suggested that fish densities were marginal for sustaining breeding seabirds at that time. Planktivorous Least Auklets Aethia pusilla and Parakeet Auklets Cyclorrhynchus psittacula foraged almost exclusively in Bering Sea waters. Short-tailed Shearwaters Puffinus tenuirostris and Tufted Puffins Fratercula cirrhata foraged in transitional waters at the front between Coastal and Bering Sea currents.

Alaska↗
USGS1988

Effects of the 1982-83 El Niño – Southern Oscillation on Pacific Ocean bird populations

Seabird reproductive success, population size, and movements in the Pacific region responded dramatically to the 1982-83 El Niño – Southern Oscillation (ENSO). At sites within the North and South Pacific Gyres, the onset of seabird responses tracked oceanographic changes related to ENSO; to the north of the gyres, responses were delayed 1 yr. Reproductive failures and high adult mortality were detected at all sites investigated. Post-ENSO, the return to “normal” nesting patterns depended on species and locality. The 1982-83 ENSO revealed a dimension to the variability in seabird reproductive biology only now appreciated by ornithologists.

Conference Paper↗