Arctic Vessel Traffic in the Bering Strait

This brief examines the risks posed by increasing vessel traffic and outlines a series of mitigation measures that authorities can implement to protect all those who depend on the Bering Strait—wildlife and indigenous communities, as well as ships and their crews

Comparison of environmental conditions in the Bering Sea and Davis Strait and the effects on microwave signature returns; March and April, 1979

Aircraft data collected in the Bering Sea in March, 1979 using a 6.6 GH sub z (C Band) microwave radiometer and a 13.9 GH sub z (Ku Band) scatterometer, reinforce the difficulties in interpreting first year ice types found near the ice edge in a marginal ice zone. An ice interpretation scheme using data taken with a 13.3 GH sub z (Ku Band) scatterometer and a 19.4 GH sub z (K Band) radiometer in Davis Strait also shows ambiguity in the first year ice signal and indicates that ice interpretation becomes more difficult near the ice edge and under warmer conditions. This report also compares X Band SAR data taken in Davis Strait with similar imagery collected in the Bering Sea. Ice core samples from the Bering test area offer a basis for speculation on changes in ice morphology which affect the signature return at the ice edge, and help explain the difficulty of the sensors in discerning the two different ice types found on the photography and in the core samples

The large‐scale freshwater cycle of the Arctic

This paper synthesizes our understanding of the Arctic\u27s large‐scale freshwater cycle. It combines terrestrial and oceanic observations with insights gained from the ERA‐40 reanalysis and land surface and ice‐ocean models. Annual mean freshwater input to the Arctic Ocean is dominated by river discharge (38%), inflow through Bering Strait (30%), and net precipitation (24%). Total freshwater export from the Arctic Ocean to the North Atlantic is dominated by transports through the Canadian Arctic Archipelago (35%) and via Fram Strait as liquid (26%) and sea ice (25%). All terms are computed relative to a reference salinity of 34.8. Compared to earlier estimates, our budget features larger import of freshwater through Bering Strait and larger liquid phase export through Fram Strait. While there is no reason to expect a steady state, error analysis indicates that the difference between annual mean oceanic inflows and outflows (∼8% of the total inflow) is indistinguishable from zero. Freshwater in the Arctic Ocean has a mean residence time of about a decade. This is understood in that annual freshwater input, while large (∼8500 km3), is an order of magnitude smaller than oceanic freshwater storage of ∼84,000 km3. Freshwater in the atmosphere, as water vapor, has a residence time of about a week. Seasonality in Arctic Ocean freshwater storage is nevertheless highly uncertain, reflecting both sparse hydrographic data and insufficient information on sea ice volume. Uncertainties mask seasonal storage changes forced by freshwater fluxes. Of flux terms with sufficient data for analysis, Fram Strait ice outflow shows the largest interannual variability

Atlantic Ocean Heat Transport Enabled by Indo-Pacific Heat Uptake and Mixing

The ocean transports vast amounts of heat around the planet, helping to regulate regional climate. One important component of this heat transport is the movement of warm water from equatorial regions toward the poles, with colder water flowing in return. Here, we introduce a framework relating meridional heat transport to the diabatic processes of surface forcing and turbulent mixing that move heat across temperature classes. Applied to a (1/4)° global ocean model the framework highlights the role of the tropical Indo‐Pacific in the global ocean heat transport. A large fraction of the northward heat transport in the Atlantic is ultimately sourced from heat uptake in the eastern tropical Pacific. Turbulent mixing moves heat from the warm, shallow Indo‐Pacific circulation to the cold deeper‐reaching Atlantic circulation. Our results underscore a renewed focus on the tropical oceans and their role in global circulation pathways

The Bowhead Whale, Balaena mysticetus: Its Historic and Current Status

The bowhead whale, Balaena mysticetus, is currently listed as endangered under the Endangered Species Act of 1973 and as depleted under the Marine Mammal Protection Act of 1972. Literature on the species is updated since 1984, and elements are reviewed that may contribute to the evaluation of the status of bowhead whale stocks

Reconstructed warm season temperatures for Nome, Seward Peninsula, Alaska

[1] Understanding of past climate variability in the Bering Strait region and adjacent land areas is limited by a paucity of long instrumental and paleoclimatic records. Here we describe a reconstruction of May - August temperatures for Nome, Seward Peninsula, Alaska based on maximum latewood density data which considerably extends the available climatic information. The reconstruction shows warm conditions in the late 1600s and middle-20th century and cooler conditions in the 1800s. The summer of 1783, coinciding with the Laki, Iceland volcanic event, is among the coldest in the reconstruction. Statistically significant relationships with the North Pacific Index and Bering-Chukchi sea surface temperatures indicate that the Seward tree-ring data are potentially useful as long-term indices of atmosphere-ocean variability in the region.</p

The Geographic Distribution of Bowhead Whales, Balaena mysticetus, in the Bering, Chukchi, and Beaufort Seas: Evidence from Whaleship Records, 1849–1914

We have extracted, digitized, and analyzed information about bowhead whales, Balaena mysticetus, contained in records of whaling cruises that were undertaken in the Bering, Chukchi, and Beaufort Seas from 1849 to 1914. Our database consists of 65,000 days of observations which provide insights into whether this bowhead stock may comprise more than one population

Ecology of Juvenile Walleye Pollock, Theragra chalcogramma: Papers from the workshop "The Importance of Prerecruit Walleye Pollock to the Bering Sea and North Pacific Ecosystems" Seattle, Washington, 28-30 October 1993

The Alaska Fisheries Science Center (AFSC), National Marine Fisheries Service (NMFS), hosted an international workshop, 'The Importance of Prerecruit Walleye Pollock to the Bering Sea and North Pacific Ecosystems," from 28 to 30 October 1993. This workshop was held in conjunction with the annual International North Pacific Marine Science Organization (PICES) meeting held in Seattle. Nearly 100 representatives from government agencies, universities, and the fishing industry in Canada, Japan, the People's Republic of China, Russia, and the United States took part in the workshop to review and discuss current knowledge on juvenile pollock from the postlarval period to the time they recruit to the fisheries. In addition to its importance to humans as a major commercial species, pollock also serves as a major forage species for many marine fishes, birds, and mammals in the North Pacific region. (PDF file contains 236 pages.

Controls on zooplankton assemblages in the northeastern Chukchi Sea

Thesis (Ph.D.) University of Alaska Fairbanks, 2016The Chukchi Sea is a broad and shallow marginal sea of the western Arctic Ocean that lies between the Bering Sea and the deeper Amerasian basin. It plays a pivotal role as the only gateway for transporting heat, carbon, nutrients, and plankton from the North Pacific into the Arctic Ocean. I examined the seasonal and inter-annual variability of the zooplankton communities in the northeastern region of the Chukchi Sea as part of a high-resolution multidisciplinary ecosystem study. Specifically, I examined how the physical onset of each open water season influenced the composition, abundance, and biomass of zooplankton assemblages from the 2008 to 2010 field seasons. Copepods in the genus Pseudocalanus are key members of the Chukchi community, and may be undergoing species-level biogeographic shift in response to climate change. I determined the degree of gene flow and population connectivity in the Chukchi Sea through comparative phylogeographic analysis of the Pseudocalanus species complex to the northern Gulf of Alaska and Beaufort Sea. I then investigated the extent to which biogeochemical factors influence these zooplankton assemblages by relating a portion of the seasonal production to concurrent changes in herbivorous mesozooplankton biomass during 2010 and 2011. This work demonstrates just how complex and variable marine ecosystems of the western Arctic are, where multidisciplinary and analytical approaches will become essential in detecting change, especially with the rate of present-day climate perturbations.Chapter 1: Seasonal and interannual variation in the planktonic communities of the northeastern Chukchi Sea during the summer and early fall -- Chapter 2: Phylogeography and connectivity of the Pseudocalanus (Copepoda: Calanoida) species complex in the eastern North Pacific Ocean and the Pacific Arctic Region -- Chapter 3: Community production in the northeastern Chukchi Sea and its relationship to phytoplankton and mesozooplankton biomass, 2010-2011 -- General Conclusions -- References