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The Bering Sea is the second largest marginal sea in the North Pacific and is one of the areas with highest biological productivity in high-latitude waters. The continental shelf of the Bering Sea hosts large populations of marine mammals and fishery resources. However, the smaller organisms in benthic ecosystems, including meiofauna, have been largely overlooked in this area, despite their potential importance in ecosystem functioning and the resultant biogeochemical cycles. This study analyzed spatial differences in the total abundance and community structure of the metazoan meiofauna at five stations around the Bering Canyon, located at the southeastern margin of the Bering Sea. Their association with environmental factors in sediments was also studied. The results confirmed that the investigated stations had meiofaunal standing stocks that were comparable to those of other Arctic seas. Among the investigated sediment biological and geochemical parameters (total organic carbon, median grain size, prokaryotic cell numbers, etc.), multivariate analyses showed that the C/N of organic matter in sediments was the main factor associated with meiofaunal community structure.

The Chukchi Sea is a marginal sea in the Arctic with a mixed layer that is a few psu units saltier than ambient open Arctic water. Such higher salinity is maintained by salty and warm Pacific water inflow through the Bering Strait, implying that changes in inflow characteristics should affect the thermohaline properties of the Chukchi Sea. Recently, two additional controlling factors have been highlighted – the strength of boundary currents along the Siberian coast, and meridional exchanges due to wind-driven transport. In this note, we illustrate that anomalous fresh Chukchi Sea surface salinity in summer-autumn 2021 may be related to the anomalous southward shift of the ice edge and its meltwater source. These anomalous ice conditions occur concurrently with anomalously low Beaufort High, anomalous westerly cyclonic winds over ice-covered and open water Chukchi Sea, and related southward Ekman transport of late season meltwater. The September 2021 ice expansion was the largest in 1981–2021 detrended ice records.

Salinity in the Bering Sea is vital for the physical environment that is tied to the productive ecosystem and the properties of Pacific waters transported to the Arctic Ocean. Its salinity variability reflects many fundamental processes, including sea ice formation/melting and river runoff, but its spatial and temporal characteristics require better documentation. This study utilizes remote sensing products and in situ observations collected by saildrone missions to investigate Sea Surface Salinity (SSS) variability. All Satellite products resolve the large-scale pattern set up by the relatively salty deep basin and the fresh coastal region, but they can be inaccurate near the ice edge and near land. The SSS annual cycle exhibits seasonal maxima in winter to spring, and minima in summer to fall. The amplitude and timing of the seasonal cycle are variable, especially on the eastern Bering Sea shelf. SSS variability recorded by both saildrone, and satellite instruments provide unprecedented insights into short-term oceanic processes including sea ice melting, wind-driven currents during weather events, and river plumes etc. In particular, the Soil Moisture Active Passive (SMAP) satellite demonstrates encouraging skills in capturing the freshening signals induced by spring sea ice melting. The Yukon River plume is another source of intense SSS variability. Surface wind forcing plays an essential role in controlling the horizontal movement of plume water and thereby shaping the SSS seasonal cycle in local regions. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

This dissertation uses multiple case studies to examine the role of environmental disturbances and human activity on microbial physiology and community composition. In ecological theory, environmental disturbances, which govern species succession, adaptation, and evolution and can shift ecosystem function, are critical components of ecosystems. George Hutchinson postulated the so-called “paradox of the plankton” in which the highly diverse plankton communities present in marine and freshwater systems seemed inconceivable due to the relatively homogenous aquatic environment. The unfathomable spatial and temporal scales of marine microbes in their environments help explain this diversity and the role of relatively small-scale disturbances and gradients in marine ecosystems but it also makes it difficult to understand how a variety of large-scale human induced perturbations may shift the overall composition and function of ecosystems. In the modern world, understanding and being able to predict or anticipate how our actions will influence the inherent nature and diversity of the environment as well as how ecosystem services will be altered is extremely important for the survival of the human species and a sustainable future for the Earth. This far-reaching and broad topic is of considerable focus in the research community and is being addressed at both large and small spatiotemporal scales. In this dissertation, I explore three distinct cases in which environmental disturbance and anthropogenic impacts influence marine microbes. (1) The first case study explores the impacts of an oil spill in the marine environment on phytoplankton physiology. Through laboratory experimentation on representatives of two important phytoplankton groups, the coccolithophore, Emiliania huxleyi, and the diatom, Pseudo-nitzschia australis, results showed that oil exposure negatively impacted the growth of these species though E. huxleyi appeared to be more tolerant of oil exposure than P. au

Deglacial sea surface conditions in the subarctic North Pacific and marginal seas are the subject of increasing interest in paleoceanography. However, a cohesive picture of near-surface oceanography from which to compare inter and intra-regional variability through the last deglaciation is lacking. We present a synthesis of sea surface temperature covering the open North Pacific and its marginal seas, spanning the past 20 ka using proxy records from foraminiferal calcite (δ18O and Mg/Ca) and coccolithophore alkenones (Uk’37). Sea surface temperature proxies tend to be in agreement through the Holocene, though Uk’37 records are often interpreted as warmer than adjacent δ18O or Mg/Ca records during the Last Glacial Maximum and early deglaciation. In the Sea of Okhotsk, Holocene discrepancies between δ18O and Uk’37 may be the result of changes in near-surface stratification. We find that sea-surface warming occurred prior to the onset of the Bølling-Allerød (14.7 ka) and coincident with the onset of the Holocene (11.7 ka) in much of the North Pacific and Bering Sea. Proxy records also show a cold reversal roughly synchronous with the Younger Dryas (12.9–11.7 ka). After the onset of the Holocene, the influence of an intensified warm Kuroshio Current is evident at higher latitudes in the Western Pacific, and an east-west seesaw in sea surface temperature, likely driven by changes in the strength of the North Pacific Gyre, characterizes the open interglacial North Pacific.

We created, for the first time, a map of sea ice production in the Bering Sea, based on thin-ice thickness data from the Advanced Microwave Scanning Radiometers (AMSR-E and AMSR2) with a heat flux calculation. We used the AMSR-E thin-ice algorithm developed for the Arctic Ocean with some modification. We provided a 16-yr data set of ice production from the 2002/2003 to 2018/2019 seasons, excepting the 2011/2012 season. It is found that the Anadyr polynya has by far the highest sea ice production (average of 93 km(3)/yr) and accounts for more than 30% of all polynya ice production in the Bering Sea. The combined ice production in the Anadyr, Anadyr Strait, and St. Lawrence polynyas becomes the second-largest ice production during the AMSR-E period in the Northern Hemisphere. It is considered that the high ice production in the Anadyr polynya produces cold, saline, nutrient-rich water, so-called Anadyr Water, which would contribute to the formation of the cold halocline layer and high biological productivity. The ice production in the Anadyr polynya shows very large year-to-year variability. The record low ice extent year of the 2017/2018 season is also the lowest ice production year; the production is only one tenth of the highest value, observed during the 2015/2016 season. The high sensitivity of the wind direction and strength to the location of the Aleutian Low causes this large variability. We also built reconstruction schemes of ice production in the polynyas, using the offshore wind and air temperature, by multiple linear regression.

We measured dissolved radiocesium (134Cs and 137Cs) in seawater collected in the western subarctic area of the North Pacific Ocean, Bering Sea, and Arctic Ocean in 2015 and 2017. The radiocesium released from the accident of the Fukushima Dai-ichi nuclear power plant (FNPP1) in March 2011 was still observed in the surface seawater of the western subarctic area and Bering Sea. Between 2015 and 2017, the radiocesium concentration decreased and increased in the western subarctic area and the Bering Sea, respectively. The increase in the Bering Sea was probably derived from the long-range transport of the FNPP1-derived radiocesium into the Bering Sea with the subarctic gyre circulation in the North Pacific. The FNPP1-derived radiocesium was not detected in the Arctic Ocean in 2015 unlike that observed in 2014, which suggests a restricted transport of the FNPP1-derived radiocesium from the Bering Sea to the Arctic Ocean in 2015. The significant elevation in the radiocesium concentration in the Bering Sea in 2017 associated with the long-range transport implies the increase in the transport of the FNPP1-derived radiocesium into the Arctic Ocean in the future.

We created, for the first time, a map of sea ice production in the Bering Sea, based on thin-ice thickness data from the Advanced Microwave Scanning Radiometers (AMSR-E and AMSR2) with a heat flux calculation. We used the AMSR-E thin-ice algorithm developed for the Arctic Ocean with some modification. We provided a 16-yr data set of ice production from the 2002/2003 to 2018/2019 seasons, excepting the 2011/2012 season. It is found that the Anadyr polynya has by far the highest sea ice production (average of 93 km(3)/yr) and accounts for more than 30% of all polynya ice production in the Bering Sea. The combined ice production in the Anadyr, Anadyr Strait, and St. Lawrence polynyas becomes the second-largest ice production during the AMSR-E period in the Northern Hemisphere. It is considered that the high ice production in the Anadyr polynya produces cold, saline, nutrient-rich water, so-called Anadyr Water, which would contribute to the formation of the cold halocline layer and high biological productivity. The ice production in the Anadyr polynya shows very large year-to-year variability. The record low ice extent year of the 2017/2018 season is also the lowest ice production year; the production is only one tenth of the highest value, observed during the 2015/2016 season. The high sensitivity of the wind direction and strength to the location of the Aleutian Low causes this large variability. We also built reconstruction schemes of ice production in the polynyas, using the offshore wind and air temperature, by multiple linear regression.

Southeastern Bering Sea is one of the highest surface productivity area in the open ocean due to strong upwelling along the Bering canyon. However, the benthic geochemistry and organisms living in the area have been largely overlooked. In August 2017, surface sediment was sampled from four stations along a transect at depths between 1536 and 103 meters in the Bering canyon with JAMSTEC R/V Mirai. Bottom-water hypoxia was recorded in the two deepest stations (1536 and 536 m). At these stations, the oxygen penetrated down to 5 mm in the sediment due to siltier and much organic-rich sediments in the deeper stations while oxygen penetration was about 20 mm at stations 103 and 197 m deep with coarse-grained sediment stations. Foraminiferal number of species and abundances were higher in the Unimak pass depression station E2 (197 m). Abundance did not change significantly between stations, suggesting that foraminiferal densities are not affected by the hypoxic conditions but are rather controlled by organic matter and nutrients availability. At the upper bathyal and middle bathyal stations, living foraminiferal communities were in general dominated by Uvigerina peregrina, Nonionella pulchella, Elphidium batialis, Globobulimina pacifica, Reophax spp., and Bolivina spathulata while the shallower stations exhibited large densities of Uvigerina peregrina, Cibicidoides wuellerstorfi, Recurvoidela bradyi, Globocassidulina subglobosa, and Portatrochammina pacifica. More than 50% of the individuals have a potential to accumulate nitrate in their cell (from 3 to 648 mmol/L; which is from 100 to 4000 times larger than the highest concentration measured in pore water). Onboard denitrification measurements confirmed that B. spathulata, N. pulchella and G. pacifica could reduce nitrate through denitrification and foraminiferal denitrification could contribute over 6% to benthic nitrate reduction at the southeast Bering Sea. Although the foraminiferal contributions were smaller than th

The Eocene (~50–45 Ma) major absolute plate motion change of the Pacific plate forming the Hawaii‐Emperor bend is thought to result from inception of Pacific plate subduction along one of its modern western trenches. Subduction is suggested to have started either spontaneously, or result from subduction of the Izanagi‐Pacific mid‐ocean ridge, or from subduction polarity reversal after collision of the Olyutorsky arc that was built on the Pacific plate with NE Asia. Here we provide a detailed plate‐kinematic reconstruction of back‐arc basins and accreted terranes in the northwest Pacific region, from Japan to the Bering Sea, since the Late Cretaceous. We present a new tectonic reconstruction of the intraoceanic Olyutorsky and Kronotsky arcs, which formed above two adjacent, oppositely dipping subduction zones at ~85 Ma within the north Pacific region, during another Pacific‐wide plate reorganization. We use our reconstruction to explain the formation of the submarine Shirshov and Bowers Ridges and show that if marine magnetic anomalies reported from the Aleutian Basin represent magnetic polarity reversals, its crust most likely formed in an ~85‐ to 60‐Ma back‐arc basin behind the Olyutorsky arc. The Olyutorsky arc was then separated from the Pacific plate by a spreading ridge, so that the ~55‐ to 50‐Ma subduction polarity reversal that followed upon Olyutorsky‐NE Asia collision initiated subduction of a plate that was not the Pacific. Hence, this polarity reversal may not be a straightforward driver of the Eocene Pacific plate motion change, whose causes remain enigmatic.

In the Bering Sea shelf, annual changes in the sea ice extent are large. In this study, we compare the viable diatom resting stages in sediments during the summer of 2017 when the sea ice retreat was late and 2018 when the sea ice retreat was early. South of St. Lawrence Island, the germinating cell number was 10-100 times greater in 2018 than it was in 2017. The taxonomic composition also showed large annual differences: Fragilariopsis/Fossula spp., which are ice algae species, were abundant in 2017, but Thalassiosira spp. dominated in 2018. Satellite observations confirmed that sea ice diminished before the ice-edge bloom in 2018, but sea ice remained until the ice-edge bloom in 2017. This study shows that the community composition of viable diatom resting stages is largely affected by the timing of the sea ice retreat.

Pacific water is an important nutrient source for sustaining biological production in the Chukchi Sea, western Arctic Ocean, which is one of the productive regions in the world. Therefore, to understand the impacts of future environmental changes on biological production in the sea, it is crucial to understand the origins, modification processes, and spatiotemporal variations of the water masses from the Bering Sea with changes in nutrient concentrations. To improve water mass analysis in the shelf regions of the Bering and Chukchi Seas, we observed levels of humic-like fluorescent organic matter (FOMH) by using an in situ fluorometer directly connected to a temperature-salinity sensor during a cruise in the early summer of 2013 and evaluated the potential of FOMH as a third parameter of water mass analysis. The levels of FOMH were different among specific water masses in the region, and FOMH seemed to behave semiconservatively in the shelf regions of the Bering and Chukchi Seas during the early summer of 2013. The distributional pattern of FOMH implies that FOMH estimated by the in situ fluorometer has the potential to (1) separate warm water into riverine-affected Alaskan Coastal Water and historically photobleached summer Bering Basin Water; (2) distinguish the Anadyr Water, which has low FOMH levels and high nutrient concentrations, from the Bering Shelf Water; and (3) determine different formation/modification processes of dense shelf water that contains high nutrient concentrations.

Pacific water is an important nutrient source for sustaining biological production in the Chukchi Sea, western Arctic Ocean, which is one of the productive regions in the world. Therefore, to understand the impacts of future environmental changes on biological production in the sea, it is crucial to understand the origins, modification processes, and spatiotemporal variations of the water masses from the Bering Sea with changes in nutrient concentrations. To improve water mass analysis in the shelf regions of the Bering and Chukchi Seas, we observed levels of humic-like fluorescent organic matter (FOMH) by using an in situ fluorometer directly connected to a temperature-salinity sensor during a cruise in the early summer of 2013 and evaluated the potential of FOMH as a third parameter of water mass analysis. The levels of FOMH were different among specific water masses in the region, and FOMH seemed to behave semiconservatively in the shelf regions of the Bering and Chukchi Seas during the early summer of 2013. The distributional pattern of FOMH implies that FOMH estimated by the in situ fluorometer has the potential to (1) separate warm water into riverine-affected Alaskan Coastal Water and historically photobleached summer Bering Basin Water; (2) distinguish the Anadyr Water, which has low FOMH levels and high nutrient concentrations, from the Bering Shelf Water; and (3) determine different formation/modification processes of dense shelf water that contains high nutrient concentrations.

Seabirds are marine top predators and accumulate high levels of metals and metalloids in their tissues. Contamination by metals in the highly productive offshore region has become a matter of public concern. It is home to 80% of the seabird population in the U.S.A., 95% of northern fur seals (Callorhinus ursinus), and major populations of Steller sea lions (Eumetopias jubatus), walruses (Odobenus rosmarus) and whales. Here, the concentrations of eight heavy metals (Hg, Cd, Cr, Co, Ni, Cu, Zn and Pb) and a metalloid (As) in the liver and kidneys of the northern fulmar (Fulmarus glacialis), thick-billed murre (Uria lomvia), short-tailed shearwater (Puffinus tenuirostris), tufted puffin (Fratercula cirrhata) and horned puffin (Fratercula corniculata) collected in the Bering Sea were measured. As proxies of trophic level and habitat, nitrogen (δ15N) and carbon (δ13C) stable isotope ratios of breast muscles were also measured. Hepatic Hg concentration was high in northern fulmar, whereas Cd level was high in tufted puffin and northern fulmar. The Hg concentration and δ15N value were positively correlated across individual birds, suggesting that Hg uptake was linked to the trophic status of consumed prey. Furthermore, Hg concentration in our study was higher than those of the same species of seabirds collected in 1990

Pyrogenic carbon, also called black carbon (BC), is an important component in the global carbon cycle. BC produced by biomass burning or fossil fuel combustion is transported to oceans by the atmosphere or rivers. However, environmental dynamics (i.e., major sources and sinks) of BC in marine environments have not been well-documented. In this study, dissolved BC (DBC) collected from surface waters of the Chukchi Sea, the Bering Sea, and the subarctic and subtropical North Pacific were analyzed using the benzene polycarboxylic acid (BPCA) method. The DBC concentration and the ratio of B5CA and B6CA to all BPCAs (an index of the DBC condensation degree) ranged from 4.8 to 15.5 mu g-C L-1 and from 0.20 to 0.43, respectively, in surface waters of the Chukchi/Bering Seas and the North Pacific Ocean. The concentration and condensation degree of DBC in the Chukchi/Bering Seas were higher and more variable than those in the subarctic and subtropical North Pacific, which implies that the major factors controlling DBC distribution were different in these marine provinces. In the Chukchi/Bering Seas, the DBC concentration was negatively correlated to salinity but positively correlated to chromophoric dissolved organic matter (CDOM) quantity and total dissolved lignin phenol concentration estimated by CDOM parameters. These correlations indicated that the possible major source of DBC in the Chukchi/Bering Seas was Arctic rivers. However, in the North Pacific, where riverine inputs are negligible for most sampling sites, DBC was possibly derived from the atmosphere. Although spectral slopes of CDOM at 275-295 nm (an index of the photodegradation degree of CDOM) differed widely between the subarctic and subtropical North Pacific, the concentration and condensation degrees of DBC were similar between the subarctic and subtropical North Pacific, which suggests that photodegradation was not the only major factor controlling DBC distribution. Therefore, DBC distributions of the Nort

We present high-resolution records of sedimentary nitrogen (delta N-15(bulk)) and carbon isotope ratios (delta C-13(bulk)) from piston core S0201-2-85KL located in the western Bering Sea. The records reflect changes in surface nitrate utilization and terrestrial organic matter contribution in submillennial resolution that span the last 180 kyr. The delta N-15(bulk) record is characterized by a minimum during the penultimate interglacial indicating low nitrate utilization (similar to 62-80%) despite the relatively high export production inferred from opal concentrations along with a significant reduction in the terrestrial organic matter fraction (m(terr)). This suggests that the consumption of the nitrate pool at our site was incomplete and even more reduced than today (similar to 84%). delta N-15(bulk) increases from Marine Isotope Stage (MIS) 5.4 and culminates during the Last Glacial Maximum, which indicates that nitrate utilization in the Bering Sea was raised during cold intervals (MIS 5.4, 5.2, 4) and almost complete during MIS 3 and 2 (similar to 93-100%). This is in agreement with previous hypotheses suggesting that stronger glacial stratification reduced the nutrient supply from the subeuphotic zone, thereby increasing the iron-to-nutrient ratio and therefore the nitrate utilization in the mixed surface layer. Large variations in delta N-15(bulk) were also recorded from 180 to 130 ka BP (MIS 6), indicating a potential link to insolation and sea-level forcing and its related feedbacks. Millennial-scale oscillations were observed in delta N-15(bulk) and delta C-13(bulk) that might be related to Greenland interstadials.

It has been proposed that North Pacific sea surface temperature (SST) evolution was intimately linked to North Atlantic climate oscillations during the last glacial-interglacial transition. However, during the early deglaciation and the Last Glacial Maximum, the SST development in the subarctic northwest Pacific and the Bering Sea is poorly constrained as most existing deglacial SST records are based on alkenone paleothermometry, which is limited prior to 15ka B.P. in the subarctic North Pacific realm. By applying the TEX86L temperature proxy we obtain glacial-Holocene-SST records for the marginal northwest Pacific and the Western Bering Sea. Our TEX86L-based records and existing alkenone data suggest that during the past 15.5ka, SSTs in the northwest Pacific and the Western Bering Sea closely followed millennial-scale climate fluctuations known from Greenland ice cores, indicating rapid atmospheric teleconnections with abrupt climate changes in the North Atlantic. Our SST reconstructions indicate that in the Western Bering Sea SSTs drop significantly during Heinrich Stadial 1 (HS1), similar to the known North Atlantic climate history. In contrast, progressively rising SST in the northwest Pacific is different to the North Atlantic climate development during HS1. Similarities between the northwest Pacific SST and climate records from the Gulf of Alaska point to a stronger influence of Alaskan Stream waters connecting the eastern and western basin of the North Pacific during this time. During the Holocene, dissimilar climate trends point to reduced influence of the Alaskan Stream in the northwest Pacific.

Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 121 (2016): 1476–1501, doi:10.1002/2015JC011449., A new planktonic ecosystem model was constructed for the Eastern Bering Sea based on observations from the 2007–2010 BEST/BSIERP (Bering Ecosystem Study/Bering Sea Integrated Ecosystem Research Program) field program. When run with forcing from a data-assimilative ice-ocean hindcast of 1971–2012, the model performs well against observations of spring bloom time evolution (phytoplankton and microzooplankton biomass, growth and grazing rates, and ratios among new, regenerated, and export production). On the southern middle shelf (57°N, station M2), the model replicates the generally inverse relationship between ice-retreat timing and spring bloom timing known from observations, and the simpler direct relationship between the two that has been observed on the northern middle shelf (62°N, station M8). The relationship between simulated mean primary production and mean temperature in spring (15 February to 15 July) is generally positive, although this was found to be an indirect relationship which does not continue to apply across a future projection of temperature and ice cover in the 2040s. At M2, the leading direct controls on total spring primary production are found to be advective and turbulent nutrient supply, suggesting that mesoscale, wind-driven processes—advective transport and storminess—may be crucial to long-term trends in spring primary production in the southeastern Bering Sea, with temperature and ice cover playing only indirect roles. Sensitivity experiments suggest that direct dependence of planktonic growth and metabolic rates on temperature is less significant overall than the other drivers correlated with temperature described above., This work was supported by the National Science Foundation through grants ARC-1107187, ARC-1107303, and ARC-1107588, for BEST Synthesis, and PLR-1417365., 2016-08-20

Walleye pollock (Gadus chalcogrammus) support a large commercial fishery in the eastern Bering Sea despite large interannual and decadal swings in population abundance. These oscillations challenge the fishery, prompting significant effort directed to understanding the species and its recruitment. Conceptual paradigms of walleye pollock recruitment recognize that understanding the factors affecting survivorship during the first year of life is central to understanding population fluctuation. Since the first year is critical to year-class strength of this key economically and ecologically important species, we review the state of knowledge of pre-recruit walleye pollock ecology in the eastern Bering Sea during this critical first-year period, including spawning, changes in vertical and horizontal distributions, feeding, growth, body condition, transport, and predation. We then critically examine the recruitment paradigms based on the component processes that have been proposed to explain mechanisms of recruitment control. We identify paradigm strengths or weaknesses relative to our current state of knowledge, discussing relevance and validity. Finally, we identify gaps in knowledge and propose areas of future research effort.

Adult and early life stage distributions of the commercially important demersal fish Walleye Pollock (Gadus chalcogrammus) have varied in relation to the warm and cold environmental conditions on the eastern Bering Sea (EBS) shelf. Previous modelling studies indicate that transport alone does not account for the disparate juvenile distributions in warm and cold years, but that spawning locations are important. Our objective was to determine the potential connectivity of EBS pollock spawning areas with juvenile nursery areas between warm and cold years from an 18-year hindcast (1995–2012). We calculated the connectivity between larval sources and juvenile positions that were produced by a coupled biological-physical individual-based model that simulated transport, growth, and vertical behavior of pollock from the egg until the juvenile stage. Three connectivity patterns were seen in most simulations: along-isobaths to the northwest, self-retention, and transport around the Pribilof Islands. The major differences in connectivity between warm and cold years, more northwards in warm years and more off-shelf in cold years, mimicked wind-driven flow characteristics of those years that were related to winter mean zonal position of the Aleutian Low. Connectivity relationships were more sensitive to spatial alterations in the spawning areas in cold years, while they were more responsive to spawn timing shifts in warm years. The strongest connectivity to advantageous juvenile habitats originated in the well-known spawning areas, but also in a less well-studied region on the Outer Shelf. This northern Outer Shelf region emerged as a very large sink of pollock reaching the juvenile transition from all spawning sources, suggesting more thorough sampling across multiple trophic levels of this potentially important juvenile pollock nursery is needed.

Copepods in the genus Pseudocalanus are abundant in temperate-boreal waters of the Northern Hemisphere. However, their relative distributions are not well known because many species are morphologically cryptic. Here, Pseudocalanus species abundance and distribution in the southeastern Bering Sea from March to June, 2010, were determined using samples spanning the middle (50–100 m depth) and outer (>100 m depth) shelf domains. Based on analysis of mitochondrial COI sequences of 637 adult females, four species were identified; two are temperate (Pseudocalanus mimus, Pseudocalanus newmani) and two arctic (Pseudocalanus minutus, Pseudocalanus acuspes). Average genetic divergence among species was 14.7±4%. Species abundance and distribution differed significantly between the outer and middle shelf domains. For example, the temperate species P. mimus was more abundant in the outer shelf domain of the SE Bering Sea, while the arctic species P. acuspes was more abundant in the middle shelf domain. Genetic diversity within species varied. Haplotype and nucleotide diversities were higher in temperate than arctic species. No genetic structure was observed in the temperate species P. newmani or the arctic P. minutus across the outer and middle shelf domains, suggesting high levels of gene flow and connectivity across the shelf. Differences in the abundance, distribution and genetics among Pseudocalanus species in the Bering Sea highlight their unique ecological dynamics and evolutionary histories and suggest that they may have distinct responses to future environmental change.

Pseudocalanus copepods are small, abundant zooplankton in the Bering Sea ecosystem that play an important role in transferring primary production to fish and other higher trophic-level predators. Four morphologically cryptic species, the primarily arctic Pseudocalanus minutus and Pseudocalanus acuspes, and the more temperate Pseudocalanus newmani and Pseudocalanus mimus, are found within the Bering Sea. Pseudocalanus are generally considered phytoplanktivores. However, their feeding is poorly known, despite their importance to the ecosystem. In situ feeding by the three most abundant Pseudocalanus congeners, P. minutus, P. newmani, and P. acuspes, was investigated by sequencing partial 18S rDNA (ribosomal Deoxyribonucleic Acid) of gut contents from 225 individuals sampled from 8 stations across the Bering Sea in May and June of 2010. The 28,456 prey 18S rDNA sequences obtained clustered into 138 distinct prey items with a 97% similarity cut-off, and included diatoms, dinoflagellates, microzooplankton, mesozooplankton, and vascular plants. Pseudocalanus diets reflected variations in the environment, with phytoplankton sequences relatively more abundant in copepods from stations with higher water-column chlorophyll a concentrations. Feeding differences were observed between species. P. acuspes diet contained relatively more heterotrophic dinoflagellate sequences, and was significantly different from that of P. minutus and P. newmani, both of which contained relatively more diatom sequences, and between which no significant difference was observed. Feeding differences between the two primarily arctic species may be a mechanism of niche partitioning between these spatially co-located congeners and may have implications for the effects of climate change on the success of these abundant zooplankters and their many predators in this ecosystem.

Sea ice retreat, seawater warming, and now ocean acidification are recognized as physical stressors impacting the productive benthic communities on the shallow continental shelves of the northern Bering and Chukchi Seas, particularly calcifying organisms like bivalves that are prey items for benthivorous predators including walruses, eiders, and bearded seals. Using time-series benthic faunal collections and laboratory experiments, my research: 1) evaluates the abundance and dominant size class of Macoma calcarea in the northern Bering Sea and the southeastern Chukchi Sea during summer months from 1998-2014, and 2) investigates the effects of ocean acidification on growth and oxygen consumption of two size classes of three dominant bivalve species, M. calcarea, Astarte montagui, and Astarte borealis. Results suggest a northward shift in bivalve distribution (p < 0.01) and a recent size reduction at both sites. Experimental results suggest that one dominant size class (2.1-3 cm) will be more susceptible to ocean acidification.

Causes and consequences of differences in seabird foraging strategies between breeding colonies are not well understood. We tested whether body size of a pursuit-diving seabird, the thick-billed murre Uria lomvia, differs between breeding colonies and, if so, how size differences can be understood in the context of differences in foraging behavior, habitat use, and breeding performance. We measured adult murres over 3 seasons (2008 to 2010) at 2 of the Pribilof Islands, St. Paul and St. George, located on the continental shelf of the Bering Sea at different distances from the shelf break. Body mass and size were positively associated with deep diving and negatively associated with long flights, suggesting morphology influences foraging and commuting efficiency. Murres from St. Paul (farther from the shelf break) were larger than those from St. George (nearer the shelf break), foraged exclusively in the middle shelf domain, made deep dives during daylight, and fed on larger benthic prey. In contrast, smaller murres from St. George commuted greater distances to beyond the shelf break, made shallow dives at night, and fed on smaller, high-energy, schooling, vertical-migrating prey. Both foraging strategies resulted in similar chick-feeding rates and fledging success. The largest and the smallest murres experienced less stress during breeding compared to intermediate-sized murres, suggesting divergent selection for body size between islands. Nesting murres, as central-place foragers, may experience strong selection pressure on body size and other adaptive traits that reflect differences between breeding colonies in foraging ecology and the acquisition of resources for reproduction.

Due to processes that are poorly understood, the arctic/subarctic region is currently warming at approximately twice the rate of the rest of the globe, and these regional changes may in turn have important consequences on global climate. The Bering Sea is an ideal location to study the relationship between sea ice distribution, ocean circulation, and biological productivity, which are all thought to be components of important interactions that both respond to and influence climate changes on regional (North Pacific) to global scales. Geologic records are essential for understanding and predicting future oceanic and climatic changes, but most previous studies of Bering Sea and North Pacific climate and oceanic conditions were limited by short records that only spanned one glacial-interglacial climate cycle (~100 kyr). This dissertation presents new geochemical and sedimentological records of oceanic and climatic conditions over the past 1.2 Myr using sediment cores from Integrated Ocean Drilling Program Site U1342 (54.83N, 176.92E, 818 m water depth) in the Bering Sea, providing an unprecedented opportunity to examine trends over multiple glacial-interglacial cycles. Long benthic foraminiferal stable isotope records from Site U1342 provide the first evidence of an important recurring relationship in which extremely cold glacial conditions lead to enhanced Bering Sea ice extent and enhanced local formation of North Pacific Intermediate Water (NPIW), the water mass primarily associated with large-scale North Pacific circulation and heat transport. These results contradict model predictions for weaker NPIW formation during extreme glacial conditions and show that North Pacific and North Atlantic circulation acted in phase on glacial-interglacial timescales. Furthermore, new records of nitrate utilization based on nitrogen isotopes demonstrate that glacial climates were consistently associated with enhanced physical stratification in the Bering Sea, which resulted in inc

© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Ecology Progress Series 532 (2015): 269-281, doi:10.3354/meps11366., Understanding habitat use of critically endangered North Pacific right whales (NPRWs, Eubalaena japonica) is important to better evaluate the potential effects of anthropogenic activities and climate change on this species. Satellite transmitters were deployed on individual right whales in 2004, 2008 and 2009 to investigate whether their space-use patterns in the Southeastern Bering Sea (SEBS) were influenced by environmental conditions and to assess habitat use in areas of human interest. Whales were monitored for an average of 40 d (range 29-58 d) between July and October, a period in which they inhabited the SEBS shelf. Individuals tagged in 2008-2009 (cold years) remained in the middle shelf domain, travelled at a slower rate and showed a spatially more restricted habitat use than a whale tagged in 2004 (a warm year). Monte Carlo tests suggested that NPRWs associated with the cold pool (remnant winter water in the bottom layer of the middle shelf domain) during cold years, which is likely due to higher copepod abundance and reduced competition with other copepod predators within the cold pool. Telemetry data indicated that a Critical Habitat designated by the US National Marine Fisheries Service encompasses the main feeding range of NPRWs in the Bering Sea. Two whales briefly visited the North Aleutian Basin, an area previously considered for oil and gas development. Small sample sizes precluded conclusive comparisons of space-use patterns among years with significantly different temperature regimes, but we hypothesize that habitat use in the SEBS varies with these regimes because of concomitant changes in the abundance of the whales primary copepod prey. Long-term evaluation of space-use patterns of NPRWs is required to further understand their habits in the feeding grounds in light of global warming and the potential for increased anthropogenic activities., Funding for this research was provided by the North Pacific Research Board (NPRB, Project #720) and by the former Minerals Management Service (now Bureau of Ocean Energy Management, BOEM). This paper is contribution 558 from NPRB.

ELECTRONIC FILE CHARACTERISTICS: 1 file; video file (.WMV). PHYSICAL DESCRIPTION: 1 CD-ROM; 4 3/4 in.; 445 MB. ABSTRACT: The U.S. Coast Guard has an increasing demand to ensure the safety, security, and stewardship of the nation's Arctic waters. Environmental changes and economic incentives are driving a transformation of maritime activity in the Arctic region, including future resource (development) in the Chukchi and Beaufort Seas, foreign tankers that transit through the Bering Strait and Sea using the northern sea routes, and adventure cruises pressing even further into the Arctic. In order to meet this demand, the Coast Guard deploys to waters off northern Alaska as part of District 17's Operation Arctic Shield. The yearly Arctic Shield operational exercises are part of an on-going effort to strengthen Federal and regional maritime partnerships in the Arctic Ocean and to ensure that the Coast Guard can respond appropriately when facing the unique needs and challenges of the region. The Coast Guard's Research and Development Center participated in Arctic Shield 2013 with the goal to build on the Center's previous efforts investigating oil-recovery-in-ice capabilities and identifying technologies and techniques with the potential to improve spill response effectiveness in Arctic ice. In 2013, the Coast Guard RDC successfully examined small unmanned aviation systems, an oleophilic brush-skimmer, an autonomous underwater vehicle, a remotely operated underwater vehicle, and the National Oceanic and Atmospheric Administration computer based Environmental Response Management Application. Please note that these were evaluations of technology categories and not specific manufacturer performance evaluations. This video is a summary of that technology evaluation., Video; running time, 19:07.

The seasonal cycle of sea ice variability in the Bering Sea, together with the thermodynamic and dynamic processes that control it, are examined in a fine resolution (1/10°) global coupled ocean/sea-ice model configured in the Community Earth System Model (CESM) framework. The ocean/sea-ice model consists of the Los Alamos National Laboratory Parallel Ocean Program (POP) and the Los Alamos Sea Ice Model (CICE). The model was forced with time-varying reanalysis atmospheric forcing for the time period 1970-1989. This study focuses on the time period 1980-1989. The simulated seasonal-mean fields of sea ice concentration strongly resemble satellite-derived observations, as quantified by root-mean-square errors and pattern correlation coefficients. The sea ice energy budget reveals that the seasonal thermodynamic ice volume changes are dominated by the surface energy flux between the atmosphere and the ice in the northern region and by heat flux from the ocean to the ice along the southern ice edge, especially on the western side. The sea ice force balance analysis shows that sea ice motion is largely associated with wind stress. The force due to divergence of the internal ice stress tensor is large near the land boundaries in the north, and it is small in the central and southern ice-covered region. During winter, which dominates the annual mean, it is found that the simulated sea ice was mainly formed in the northern Bering Sea, with the maximum ice growth rate occurring along the coast due to cold air from northerly winds and ice motion away from the coast. South of St Lawrence Island, winds drive the model sea ice southwestward from the north to the southwestern part of the ice-covered region. Along the ice edge in the western Bering Sea, model sea ice is melted by warm ocean water, which is carried by the simulated Bering Slope Current flowing to the northwest, resulting in the S-shaped asymmetric ice edge. In spring and fall, similar thermodynamic and dynamic patte

A fine-resolution (1/10°) ocean/sea ice model configured in the Community Earth System Model framework is compared with observations and studied to determine the basin-scale and local balances controlling the variability of sea ice anomalies from the mean seasonal cycle in the Bering Sea for the time period 1980–1989. The model produces variations in total Bering Sea ice area anomalies that are highly correlated with observations. Surface air temperature, which is specified from reanalysis atmospheric forcing, strongly controls the ice volume variability in this simulation. The thermodynamic ice volume change is dominated by surface energy flux via atmosphere-ice sensible heat flux, except near the southern ice edge where it is largely controlled by ocean-ice heat flux. While thermodynamic processes dominate the variations in ice volume in the Bering Sea on the large scale, dynamic processes are important on the local scale near ice margins (both oceanic and land), where dynamic and thermodynamic ice volume changes have opposite signs and nearly cancel each other. Ice motion is generally consistent with winds driving the flow, except near certain straits in the north where ice motion largely follows ocean currents. Two key climate events, strong ice growth with cold air temperature and northerly wind anomalies in February 1984 and weak ice growth with warm air temperature and southerly wind anomalies in February 1989, are studied here in detail. While the processes controlling the ice changes are generally similar to those in other years, these large events help reveal the characteristic spatial patterns of ice growth/melt and transport anomalies.

The long-term goal of this collaborative research effort is to enhance the understanding of how variability in physical, biological, and acoustic signals impact marine mammal habitat use. This is especially critical in areas like the Bering Sea where global climate change can lead to rapid changes of the entire ecosystem. The Arctic is projected to experience ice-free summers within 30 years (Wang & Overland, 2009). This will have significant impacts for the natural ecosystem dynamics and human use associated with transportation, fishing, military activity, and energy exploration. Baseline measurements will play an important role in mitigation efforts and environmental assessments as military activity increases in the region. A major component of this research is to use passive ambient sound to identify the physical environment present, and then to use this information to interpret the biological data collected., The original document contains color images.

Author Posting. © Inter-Research, 2013. This article is posted here by permission of Inter-Research for personal use, not for redistribution. The definitive version was published in Marine Ecology Progress Series 490 (2013): 267-284, doi:10.3354/meps10457., Due to the seriously endangered status of North Pacific right whales Eubalaena japonica, an improved understanding of the environmental factors that influence the species’ distribution and occurrence is needed to better assess the effects of climate change and industrial activities on the population. Associations among right whales, zooplankton, and the physical environment were examined in the southeastern Bering Sea during the summers of 2008 and 2009. Sampling with nets, an optical plankton counter, and a video plankton recorder in proximity to whales as well as along cross-isobath surveys indicated that the copepod Calanus marshallae is the primary prey of right whales in this region. Acoustic detections of right whales from sonobuoys deployed during the cross-isobath surveys were strongly associated with C. marshallae abundance, and peak abundance estimates of C. marshallae in 2.5 m depth strata near a tagged right whale ranged as high as 106 copepods m-3. The smaller Pseudocalanus spp. was higher in abundance than C. marshallae in proximity to right whales, but significantly lower in biomass. High concentrations of C. marshallae occurred in both the surface and bottom layers of the highly stratified water column, but there was no evidence of diel vertical migration. Instead, occurrence of C. marshallae in the bottom layer was associated with elevated near-bottom light attenuance and chlorophyll fluorescence, suggesting C. marshallae may aggregate at depth while feeding on resuspended phytodetritus. Despite the occasional presence of strong horizontal gradients in hydrographic properties, no association was found between C. marshallae and either fronts or phytoplankton distribution., This study was funded by the US Depart - ment of the Interior, Minerals Management Service (MMS; now Bureau of Ocean Energy Management), through Interagency Agreement No. M07RG13267 (AKC 063) with the US Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), as part of the MMS Alaska Environmental Studies Program.

Population growth is affected by several factors such as climate, species interaction and harvesting pressure. However, additional complexity can arise if fishing increases the sensitivity to environmental variability. To predict the effects of fisheries and climate on marine populations, there is a need for improved understanding of how they affect key ecological processes such as population growth. In this study, we used a comparative approach investigating commercially fished species across different ecosystems: the Norwegian Sea−Barents Sea (Northeast Arctic cod), the North Sea (North Sea cod), the Atlantic Ocean (European hake), the Mediterranean Sea (European hake), and the Gulf of Alaska and Bering Sea (walleye pollock). Our objective was to compare the effects of commercial fisheries, age structure and environmental variability on population growth rate. We show that although all stocks experienced a decline in abundance, only 3 of them showed a concomitant decreasing trend in generation time (South Atlantic hake, North Atlantic hake and Northeast Arctic cod), suggesting a fishing-induced erosion in their age structure. Intra-specific analysis shows that changes in generation time triggered an increase in the relative contribution of recruitment to population growth. Furthermore, the contribution from recruitment to population growth changes due to large-scale climate indices or regional-scale environmental covariates, such as sea temperature. This study illustrates how and where the interaction between large-scale ecological patterns and regional/short-scale processes are important for designing management regulations

LONG-TERM GOALS: Utilize a constellation of satellite radars to monitor the melting and freezing cycles of the Arctic Ocean north of 65 deg. From difference maps of a timeseries of images deduce changes in ice extent, ice-type, and lead expansion/contraction with temporal resolutions from hours to days. Ultimately provide a routine Arctic coverage and generate products for operational purposes, and as validation, boundary conditions, and initialization to numerical ice-ocean forecast models.

Due to the opening of the Northwest Passage and interest in Arctic resources, naval activities (amongst others) and ocean noise are increasing in northerly beluga waters. Through data acquired in a capture-release project, this work examines the frequencies and sound levels to which wild belugas are sensitive. A standard audiogram is being determined from the wild samples, noting the variation between animals and the audiogram of maximal sensitivity. This will be compared to available hearing data from captive belugas, evaluating any differences and potentially combining the two data sets. The hearing curves will be appraised relative to demographic and health-related meta-data from the animals from which the measurements were made. Through these data analyses we seek to: 1) define the natural and baseline hearing abilities and variability in belugas, 2) place the results in the context of potential ecological influences and that of anthropogenic noise, and 3) evaluate the validity of captive-based hearing data in relation to wild animals., The original document contains color images.

Sea surface height anomalies observed by satellites in 1992-2010 are combined with monthly climatologies of temperature and salinity to estimate circulation in the southern Bering Sea. The estimated surface and deep currents are consistent with independent velocity observations by surface drifters and Argo floats parked at 1,000 m. Analysis reveals 1-3-Sv interannual transport variations of the major currents with typical intra-annual variability of 3-7 Sv. On the seasonal scale, the Alaskan Stream transport is well correlated with the Kamchatka (0.81), Near Strait (0.53) and the Bering Slope (0.37) currents. Lagged correlations reveal a gradual increase of the time the lags between the transports of the Alaskan Stream, the Bering Slope Current and the Kamchatka Current, supporting the concept that the Bering Sea basin is ventilated by the waters carried by the Alaskan Stream south of the Aleutian Arc and by the flow through the Near Strait. Correlations of the Bering Sea currents with the Bering Strait transport are dominated by the seasonal cycle. On the interannual time scale, significant negative correlations are diagnosed between the Near Strait transport and the Bering Slope and Alaskan Stream currents. Substantial correlations are also diagnosed between the eddy kinetic energy and Pacific Decadal Oscillation., Published in the Journal of Oceanography v68 p485-496, 9 Jun 2012.

A model has been developed and run with sufficiently high resolution (~9 km and 45 levels) and a large enough spatial domain to allow for realistic representation of flow through the narrow and shallow straits in the Bering Sea region. This is potentially important for quantification of long-term mean and time-dependent ocean circulation, and water mass and property exchanges between the Pacific and Arctic oceans. The mean modeled circulation in the Bering Sea is found to be in good agreement with the limited observational data. The Bering Sea Basin, Bering Slope Current, and straits on the northern shelf are identified as highly energetic regions based on eddy kinetic energy fields. Some high biological productivity regions of the northern Bering Sea identified in observational studies are coincident with regions of persistently high energy (up to 2600 cm2 s-2 at mid-depth) throughout the annual cycle. Over a twentythree year interval (1979-2001), mean transport through Bering Strait is estimated to be 0.65 Sv. Comparison of model results with published observations indicates that ocean circulation is not only variable at seasonal to interdecadal scales, but it is also responsive to short-term atmospheric forcing. Comparison with observations of nearbottom salinity indicates that the model is reasonably representing the major water mass properties. The long-term model results for the Bering Sea provide important insights into the ocean circulation and fluxes and they are a useful frame of reference for limited observations that are short-term and/or cover only a small geographic region., http://archive.org/details/ocecirculationnd109452172, Approved for public release; distribution is unlimited.

Extensive seasonal sea ice reduction has highlighted the need to evaluate the status and potential long term changes of highly productive benthic communities in the Pacific Arctic Region. Walrus that use sea ice to access offshore feeding areas are now being forced to haul out on land for part of the year, requiring them to forage for benthic prey from closer to shore. To explore this energetic problem, I conducted a caloric survey of benthic invertebrates, and evaluated relationships between caloric content and environmental variables. Latitude was the strongest non-taxonomic dependency for caloric content (ANOVA p=0.003 with taxon dependencies, p<0.001 without). Cluster analysis revealed caloric densities were higher in offshore, high nutrient Bering Sea Anadyr Water, and lower in nearshore, low nutrient Alaska Coastal Water. An evaluation of preservation techniques indicated formalin fixation increased infaunal caloric content (p<0.001), suggesting caution while converting traditional benthic population studies to caloric values.

The long-term goal of this research effort is to enhance the understanding of how variability in physical, biological, and acoustic signals impact marine mammal prey and resulting marine mammal habitat use. This is especially critical in areas like the Bering Sea where global climate change can lead to rapid changes of the entire ecosystem. The Arctic is projected to experience ice-free summers within 30 years (Wang and Overland, 2009). This will have significant impacts for the natural ecosystem dynamics and human use associated with transportation, fishing, military activity, and energy exploration. Shifts in plankton community structure are a likely response to large-scale changes in ice cover. Zooplankton population dynamics are a dominant component of the ecosystem that provide the crucial trophic link between primary production and Federally-protected species such as marine mammals. Understanding the relationship between ice cover and zooplankton community structure in different regions of the Bering Sea will provide information for predicting upper-level trophic dynamics, including marine mammal distribution and range, as sub-Arctic conditions continue to change. Baseline measurements will play an important role in mitigation efforts and environmental assessments as commercial and military activity increases in the region. The main goal of this year s effort was to relate acoustic backscatter characteristics associated with estimates of zooplankton/neckton abundance, spatial and temporal variability, dominant size class, and taxa to marine mammal detection patterns on the central and southeastern Bering Sea shelf. The first objective examines bio-physical interactions influencing the dynamics of marine mammal zooplankton and fish prey. The second objective relates the prey variability to observed patterns of marine mammal vocal detections indicative of animal presence and habitat use.

A new mean dynamic topography (MDT) for the Bering Sea is presented. The product is obtained by combining historical oceanographic and atmospheric observations with high-resolution model dynamics in the framework of a variational technique. Eighty percent of the ocean data underlying the MDT were obtained during the last 25 years and include hydrographic profiles, surface drifter trajectories, and in situ velocity observations that were combined with National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) atmospheric climatology. The new MDT quantifies surface geostrophic circulation in the Bering Sea with a formal accuracy of 2 4 cm/s. The corresponding sea surface height (SSH) errors are estimated by inverting the Hessian matrix in the subspace spanned by the leading modes of SSH variability observed from satellites. Comparison with similar products based on in situ observations, satellite gravity, and altimetry shows that the new MDT is in better agreement with independent velocity observations by Argo drifters and moorings. Assimilation of the satellite altimetry data referenced to the new MDT allows better reconstruction of regional circulations in the Bering Sea. Comparisons also indicate that MDT estimates derived from the latest Gravity Recovery and Climate Experiment geoid model have more in common with the presented sea surface topography than with the MDTs based on earlier versions of the geoid. The presented MDT will increase the accuracy of calculations of the satellite altimeter absolute heights and geostrophic surface currents and may also contribute to improving the precision in estimating the geoid in the Bering Sea.

A 1/12th-degree, pan-Arctic ice-ocean numerical model is used to better understand the circulation and exchanges in the Bering Sea. Understanding the physical oceanography of the Bering Sea is significant for the U.S. Navy due to the expected increase in ship traffic and exploration of natural resources that will likely coincide with the ongoing retreat of sea ice in the Western Arctic. This model represents a large step forward in the ability to simulate the mesoscale eddies and meanders in the Alaskan Stream and the deep Bering Sea basin, which are shown to exert a strong control on the flow into and out of the western Aleutian Island passes. Model results show that upwelling of deep Bering Sea water, which is the primary source of nutrients for important ecosystems of the Bering, Chukchi, and Beaufort seas, is enhanced by the presence of cyclonic eddies in the vicinity of canyons along the slope. High values of eddy kinetic energy in Bering and Anadyr straits help explain the areas of high biological productivity located just downstream in the Chirikov Basin and north of Bering Strait. Model results show significant horizontal and vertical shear in the flow through Bering Strait, and indicate a need for more observations of the flow structure on a continuous basis., The original document contains color images.

We studied microbially mediated diagenetic processes driven by carbon mineralization in subseafloor sediment of the northeastern Bering Sea Slope to a depth of 745meters below seafloor (mbsf). Sites U1343, U1344 and U1345 were drilled during Integrated Ocean Drilling Program (IODP) Expedition 323 at water depths of 1008 to 3172m. They are situated in the high productivity "Green Belt" region, with organic carbon burial rates typical of the high-productivity upwelling domains on western continental margins. The three sites show strong geochemical similarities. The downward sequence of microbially mediated processes in the sediment encompasses (1) organoclastic sulfate reduction, (2) anaerobic oxidation of methane (AOM) coupled to sulfate reduction, and (3) methanogenesis. The sediment contains two distinct zones of diagenetic carbonate formation, located at the sulfate-methane transition zone (SMTZ) and between 300 and 400mbsf. The SMTZ at the three sites is located between 6 and 9mbsf. The upward methane fluxes into the SMTZ are similar to fluxes in SMTZs underlying high-productivity surface waters off Chile and Namibia. Our Bering Sea results show that intense organic carbon mineralization drives high ammonium and dissolved inorganic carbon (DIC) production rates (>4.2mmolm-3y-1) in the uppermost 10mbsf and strongly imprints on the stable carbon isotope composition of DIC, driving it to a minimum value of -27‰ (VPDB) at the SMTZ. Pore-water calcium and magnesium profiles demonstrate formation of diagenetic Mg-rich calcite in the SMTZ. Below the SMTZ, methanogenesis results in 13C-enrichment of pore-water DIC, with a maximum value of +11.9‰ The imprint of methanogenesis on the DIC carbon isotope composition is evident down to a depth of 150mbsf. Below this depth, slow or absent microbially mediated carbon mineralization leaves DIC isotope composition unaffected. Ongoing carbonate formation between 300 and 400 mbsf strongly influences pore-water DIC and magnesium con

Protein comprises the largest compartment of organic nitrogen in the ocean, and makes up a major portion of organic carbon in phytoplankton. Protein has long been thought to be highly labile in the environment and rapidly lost during diagenesis. However, the analysis of dissolved and particulate organic matter with NMR has revealed that much of dissolved and particulate marine organic nitrogen is linked by amide bonds, the very bonds that join amino acids in proteins. Throughout the global ocean, total hydrolysable amino acids (THAAs, the building blocks of proteins) can be measured in the water column and sediments, yet their biosynthetic source has remained elusive. Here, analytical techniques were developed combining protein solubilizing buffer extractions, gel electrophoresis, and proteomic mass spectrometry in order to investigate the biogeochemical significance of marine protein from primary production during transport and incorporation in sediments. These techniques enabled the detection and classification of previously unidentified marine sedimentary proteins. Specific proteins were tracked through the water column to continental shelf and deeper basin (3490 m) sediments of the Bering Sea, one of the world's most productive ecosystems. Diatoms were observed to be the principal source of identifiable protein in sediments. In situ shipboard phytoplankton degradation experiments were conducted to follow protein degradation, and it was observed that individual proteins remained identifiable even after 53 days of microbial recycling. These studies show that proteins can be identified from complex environmental matrices, and the methods developed here can be applied to investigate and identify proteins in degraded organic matter from a broad range of sources. The longevity of some fraction of algal proteins indicates that carbon and nitrogen sources can be tracked down the marine water column to sediments in diatom dominated systems as well as other types of phyto

The Arctic region and Alaska--America's Arctic--provide tremendous value to the United States. Without a significant Arctic Research Program, however, those things we value in and from the Arctic--energy, food, security, biodiversity, fresh water, carbon sinks, pristine wilderness, more direct transport routes, rich indigenous cultures--cannot contribute as well or be sustained. There is little human activity we know of in the Arctic that is not knowledge based. The Arctic continues to be rich in mysteries that can only be solved with pioneering exploration and research. With greater knowledge, the Arctic region can contribute more to both the global economy and the environment. Knowledge about Arctic processes can help protect the world from expensive, unnecessary, and destructive climate change. The U.S. Arctic Research Program must strengthen its efforts on five central and crosscutting themes 1. Environmental Change of the Arctic, Arctic Ocean, and Bering Sea 2. Arctic Human Health 3. Civil Infrastructure 4. Natural Resource Assessment and Earth Science 5. Indigenous Languages, Cultures, and Identities, Presented at the 15th Annual Partners in Environmental Technology Technical Symposium & Workshop, 30 Nov ? 2 Dec 2010, Washington, DC. Sponsored by SERDP and ESTCP.

The long-term goal of this collaborative research effort is to enhance the understanding of how variability in physical, biological, and acoustic signals impact marine mammal habitat use. This is especially critical in areas like the Bering Sea where global climate change can lead to rapid changes of the entire ecosystem. Progressive climate change has the potential to expose areas of the Arctic and sub-Arctic that have been previously unavailable for civilian and military use. Baseline measurements will play an important role in mitigation efforts and environmental assessments as commercial and military activity increases in the region. The main objective of this work is to relate synoptic measurements of prey distribution, physical oceanographic process, and sound levels to marine mammal habitat use on the eastern Bering Sea shelf. Integrated data such as these will be vital in understanding the relationship between marine mammals and their environment both in the presence and absence of specific noise sources. Long term measurements will play an important role in determining the point at which cumulative effects of the environment and human activities impact animal populations, and in identifying the conditions that pose the greatest risk., Prepared in cooperation with the University of Washington (Seattle, WA) and Oregon State University (Newport, OR).

The long-term goal of this collaborative research effort is to enhance the understanding of how variability in physical, biological, and acoustic signals impact marine mammal habitat use. This is especially critical in areas like the Bering Sea where global climate change can lead to rapid changes of the entire ecosystem. Progressive climate change has the potential to expose areas of the Arctic that have been previously unavailable for civilian and military use. Baseline measurements will play an important role in mitigation efforts and environmental assessments as military activity increases in the region.

The main objective of this work is to relate synoptic measurements of prey distribution, physical oceanographic process, and sound levels to cetacean habitat use in the Bering Sea. Integrated data such as these will be vital in understanding the relationship between cetaceans and their environment both in the presence and absence of specific noise sources. Long-term measurements will play an important role in determining the point at which cumulative effects of the environment and human activities impact animal populations, and in identifying the kinds of exposure that pose the greatest risk. The Bering Sea is an ecosystem that is presently experiencing rapid climate change, has relatively healthy populations of cetaceans and supports the largest fishery in the US EEZ.

The long-term goal of this collaborative research effort is to enhance understanding of how variability in physical, biological and acoustic signals impact cetacean habitat use. In particular, what are the effects of manmade underwater sound on marine mammal health and physiology, and what are the consequences of these effects at the marine mammal population level? The objectives of this collaborative research effort are to make synoptic measurements of cetacean habitat use, prey concentrations, physical oceanographic processes, and noise levels in the Bering Sea. Integrated data such as these will be vital in understanding the relationship between cetaceans and their environment both in the presence and absence of specific noise sources. Long-term measurements will play an important role in determining the point at which cumulative effects of the environment and human activities impact animal populations, and in identifying the kinds of exposure that pose the greatest risk. The Bering Sea is an ecosystem that is presently experiencing rapid climate change, has relatively healthy populations of cetaceans and supports the largest fishery in the US EEZ.

The Polar Ice Prediction System (PIPS) Version 3.0 is a dynamic sea-ice model that forecasts conditions in all sea-ice covered areas in the northern hemisphere (down to 30 degrees north in latitude). It has a horizontal resolution of approximately 9 km. The vertical resolution in the model has been set at 45 levels so that Arctic shelves, continental slopes, and submarine ridges are accurately represented. Currently, the domain includes the Irminger, Labrador, North, and Baltic Seas on the Atlantic side and the Bering Sea, Sea of Japan, and the Sea of Okhotsk on the Pacific. The PIPS 3.0 system is based on the Los Alamos ice model and coupled (via file transfer) to the operational, global Navy Coastal Ocean Model (gNCOM). The system forecasts daily ice thickness, concentration, and drift in the Artic Ocean. This report documents the matematical formulations, flow charts, and descriptions of the programs and subroutines., Prepared in collaboration with Planning Systems, Inc., Stennis Space Center, MS.

The Polar Ice Prediction System (PIPS) Version 3.0 is a dynamic sea-ice model that forecasts conditions in all sea-ice covered areas in the northern hemisphere (down to 30 degrees north in latitude). It has a horizontal resolution of approximately 9 km. The vertical resolution in the model has been set at 45 levels so that Arctic shelves, continental slopes, and submarine ridges are accurately represented. Currently, the domain includes the Irminger, Labrador, North, and Baltic Seas on the Atlantic side and the Bering Sea, Sea of Japan, and the Sea of Okhotsk on the Pacific. The PIPS 3.0 system is based on the Los Alamos ice model and coupled (via file transfer) to the operational, global Navy Coastal Ocean Model (gNCOM). The system forecasts daily ice thickness, concentration and drift in the Artic Ocean. This report documents the setup and execution of the PIPS 3.0 system., The original document contains color images. Prepared in collaboration with Planning Systems, Inc., Stennis Space Center, MS.