Influence of the Yukon River on the Bering Sea

Physical and biological oceanography of the northern Bering Sea including the influence of the Yukon River were studied. Satellite data acquired by the Advanced Very High Resolution Radiometer (AVHRR), the LANDSAT Multispectral Scanner (MSS) and the Thematic Mapper (TM) sensor were used to detect sea surface temperatures and suspended sediments. Shipboard measurements of temperature, salinity and nutrients were acquired through the Inner Shelf Transfer and Recycling (ISHTAR) project and were compared to digitally enhanced and historical satellite images. The satellite data reveal north-flowing, warm water along the Alaskan coast that is highly turbid with complex patterns of surface circulation near the Yukon River delta. To the west near the Soviet Union, cold water, derived from an upwelling, mixes with shelf water and also flows north. The cold and warm water coincide with the Anadyr, Bering Shelf and Alaskan coastal water masses. Generally, warm Alaskan coastal water forms near the coast and extends offshore as the summer progresses. Turbid water discharged by the Yukon River progresses in the same fashion but extends northward across the entrance to Norton Sound, attaining its maximum surface extent in October. The Anadyr water flows northward and around St. Lawrence Island, but its extent is highly variable and depends upon mesoscale pressure fields in the Arctic Ocean and the Bering Sea

On the biology of eelgrass in Alaska

Thesis (Ph.D.) University of Alaska Fairbanks, 1970A collection of essays is presented that are a contribution toward a biology of eelgrass (Zostera marina L.) in Alaska. Eelgrass is the most abundant seagrass on the coast of Alaska. The distribution of the plant in Alaska is disjunct and extends from Kotzebue Sound to the southern border of the state. The present circumboreal distribution is thought to be the result of dispersal from a west Pacific origin around the Pacific rim and through the Arctic into the Atlantic. Ten widely scattered eelgrass populations in Alaska have been sampled for quantitative comparison. The highest standing stocks (1510 g dry wt/m²) were found in Kinzarof and Izembek lagoons on the Alaska Peninsula. The caloric content, chlorophyll a concentration, turion density, and leaf size varied greatly among the populations. The eelgrass in Safety Lagoon survives the arctic winter under one meter of sea ice in conditions of extremely low light intensity and anoxic water. In chemical composition, eelgrass is similar to other angiosperms, but it also reflects adaptation to the marine environment. Trace elements are accumulated in the plant in proportion to their concentration in the sea. The roots as well as the leaves function as the sites for the uptake of phosphate. Using radioactive phosphate it was shown that phosphate was absorbed greatest in the light and transported throughout the plant; a portion of the phosphate removed from solution by the roots was lost across the leaves. The metabolism of eelgrass in the dark is extremely dependent on temperature. Physiological differences exist between shallow water and deep water plants and between summer and winter plants. A depressed rate of respiration in winter is an adaptation enhancing survival in high latitudes

Discovery of Northern Fur Seals (Callorhinus ursinus) Breeding on Bogoslof Island Southeastern Bering Sea

A small group of northern fur seals (Callorhinus ursinus) including one male with two females, each with a small pup, and two lone males were discovered on Bogoslof Island, Alaska in the Bering Sea on 20 July 1980. This is the first evidence of breeding on Bogoslof, or on any island in the eastern Bering Sea other than the Pribilof Islands. We suggest that these fur seals require breeding islands adjacent to the continental shelf break where they are supported by the pelagic food web characteristic of the oceanic and outer shelf domains.Key words: fur seal, Callorhinus ursinus, Steller sea lion, Eumetopias jubatus, Aleutian Islands, Bering SeaMots clés: otarie à fourrure, Callorhinus ursinus, otarie, Eumetopias jubatus, îles Aléoutiennes, mer de Bérin

Winter Observations of Mammals and Birds, St. Matthew Island

Remore and uninhabited St. Matthew Island, lying 60 30 N, 172 30 W, on the continental shelf of the Bering Sea, is infrequently visited in summer and very rarely seen in the winter. The only signs of past human habitation are the wind-torn remains of a World War II naval observation station and the rectangular depressions of a couple of Eskimo house pits, of undetermined age, on the southwest side of the island. The last known visit to the island was during the summer of 1966. Our opportunity came on 6 and 7 February 1970, as a result of an oceanographic cruise aboard the U.S. Coast Guard icebreaker Northwind to study winter conditions in the ice-covered Bering Sea. At that time the island was covered with crusted, wind-glazed snow and locked in sea ice, with open water only along the south shore where large leads had opened up in the lee of the island. The weather was cold and very windy, temperatures ranging from 10°F to -20°F with a wind velocity averaging 30 to 40 knots, from the north. The afternoon of the 6th was clear, permitting a helicopter survey of the entire island. Most of the daylight hours of the 7th were occupied by ground investigations of the island under worsening weather conditions (overcast sky and 40-knot wind). The mammal population of the island is sparse .... We saw only arctic fox and reindeer, with no evidence of small mammals though they are known to exist there. ... Species observed on or in the vicinity of St. Matthew: Arctic Fox (Alopex lagopus), Reindeer (Rangifer tarandus), Walrus (Odobenus rosmarus), Ringed Seal (Phoca hispida,) Snowy Owl (Nyctea scandiaca), Thick-billed Murre (Uria lomvia), Harlequin (Histrionicus histrionicus), Common Eider (Somateria mollissima), King Eider (Somateria spectabilis), Old squaw (Clangula hyemalis), Pelagic Cormorant (Phalacrocorax pelagicus), Slaty-backed Gull (Larus schistisagus), Glaucous-winged Gull (Larus glaucescens), Glaucous Gull (Larus hyperboreus), Ivory Gull (Pagophila eburnea). We found a single herd of 32 reindeer at the southeast corner of the island. The animals were large and appeared to be in good condition, with impressive antlers. They are the remnant of a reindeer population introduced in 1944 that experienced a spectacular increase to 6,000 animals before crashing to 42 in the winter of 1963-64. Klein visited St. Matthew in the summer of 1966 to study the remaining reindeer and collected 10 animals, including the last male. He left 32 animals, all thought to be female, and all of which survived the intervening three and a half years up to the time of our arrival on the island. The observed marine mammal populations in the vicinity of St. Matthew proved to be disappointing. ... Ringed and bearded seals and walrus were observed some distance to the east of St. Matthew, in the edge of the sea ice in Bristol Bay; walrus were seen in large numbers north of the island, in the vicinity of St. Lawrence, so it seems likely that there should be marine mammals present in the area. ... The bird fauna of St. Matthew and vicinity was more diverse than that of the mammal. Twelve species were seen around the island, all of which, with the exception of a snowy owl, were marine and were observed in the leads and polynyas of the sea ice. Most common were murres, harlequins, and oldsquaws. ... As the ship proceeded westward from St. Matthew toward the Siberian coast, murres, black guillemots, and 4 species of gulls were seen. Several slaty-backed and glaucous-winged gulls were seen, and 3 glaucous and 2 ivory gulls observed near 60°N, 175°W. [Interestingly] ... of all the gulls seen, the slaty-back was by far the most common. This species is not considered common in Alaska

Biogeochemical Analysis of Ancient Pacific Cod Bone Suggests Hg Bioaccumulation was Linked to Paleo Sea Level Rise and Climate Change

Deglaciation at the end of the Pleistocene initiated major changes in ocean circulation and distribution. Within a brief geological time, large areas of land were inundated by sea-level rise and today global sea level is 120 m above its minimum stand during the last glacial maximum. This was the era of modern sea shelf formation; climate change caused coastal plain flooding and created broad continental shelves with innumerable consequences to marine and terrestrial ecosystems and human populations. In Alaska, the Bering Sea nearly doubled in size and stretches of coastline to the south were flooded, with regional variability in the timing and extent of submergence. Here we suggest how past climate change and coastal flooding are linked to mercury bioaccumulation that could have had profound impacts on past human populations and that, under conditions of continued climate warming, may have future impacts. Biogeochemical analysis of total mercury (tHg) and δ13C/δ15N ratios in the bone collagen of archeologically recovered Pacific Cod (Gadus macrocephalus) bone shows high levels of tHg during early/mid-Holocene. This pattern cannot be linked to anthropogenic activity or to food web trophic changes, but may result from natural phenomena such as increases in productivity, carbon supply and coastal flooding driven by glacial melting and sea-level rise. The coastal flooding could have led to increased methylation of Hg in newly submerged terrestrial land and vegetation. Methylmercury is bioaccumulated through aquatic food webs with attendant consequences for the health of fish and their consumers, including people. This is the first study of tHg levels in a marine species from the Gulf of Alaska to provide a time series spanning nearly the entire Holocene and we propose that past coastal flooding resulting from climate change had the potential to input significant quantities of Hg into marine food webs and subsequently to human consumers

A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem

Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems

Map of the Miskito Cays, Nicaragua and diagram of seagrass surveys

Map showing the location of the Miskito Cays, Nicaragua and the seagrass transect stations (upper) along with a diagrammatic representation of the transects (lower). The Miskito Cays were the location of the research expedition of Dr. John C. Ogden and his colleagues to Miskito Bank, Nicaragua aboard the R/V [Research Vessel] Alpha Helix from October 13, 1977 to November 18, 1977 where their research included studies on seagrasses, fish, sea urchins, and the green sea turtle (Chelonia mydas). To study the seagrass around the Miskito Cays, researchers did multiple transects. A transect is a research method used in ecology where a researcher lays out a line of a certain distance across a habitat with regular intervals marked on the line. The researcher then observes and records the number of occurrences of the object of study (such as a particular species of seagrass) at each regular interval on the transect line. The top image shows a map of the seagrass transect locations (MT-1 through MT-5) while the bottom image shows a diagram of what depth each seagrass transect was at, with transects MT-1 and MT-2 being at the shallow lagoon while transect MT-3 through MT-5 were at the deeper continental shelf.https://digitalcommons.usf.edu/ogden_images/1000/thumbnail.jp

Graphs showing characteristics of the plant community at a seagrass bed

Multiple bar graphs depicting characteristics of the plant community in the Miskito Cays seagrass transect done by Dr. John C. Ogden and his colleagues during their research expedition to Miskito Bank, Nicaragua aboard the R/V [Research Vessel] Alpha Helix from October 13, 1977 to November 18, 1977. A transect is an ecological research method used to describe the organisms found in an area. There are a total of ten individual bar graphs arranged into a five by two grid. Each row in the grid represents the transect location (MT-1 through MT-5) that the bar graphs represent. The map (https://digital.lib.usf.edu/SFS0070396/00001/1j) in the Cruise Narrative and Log section of the Miskito Bank Expedition, Nicaragua binder of the Dr. John Ogden Florida and Caribbean Reef Collection shows the exact locations of the research transect stations MT-1 through MT-5 at the Miskito Cays, Nicaragua. The bar graphs on the left portion of the grid show the density of plants (in grams per square meter) on the x-axis for different types and parts of plants, including plant litter, algae, leaves, and roots. The bar graphs on the right portion of the grid show both leaf area index (LAI) and density on the x-axis. Leaf area index is a measure of the amount of leaves per unit of ground. Density is shown for both turtle grass (Thalassia testudinum) and manatee grass (Syringodium filiforme).https://digitalcommons.usf.edu/ogden_images/1001/thumbnail.jp