Arctic Ocean Primary Productivity: The Response of Marine Algae to Climate Warming and Sea Ice Decline

Highlights: 1. Satellite estimates of ocean primary productivity (i.e., the rate at which marine algae transform dissolved inorganic carbon into organic material) were higher in 2018 (relative to the 2003-17 mean) for three of the nine investigated regions (the Eurasian Arctic, Bering Sea, and Baffin Bay). 2. All regions continue to exhibit positive trends over the 2003-18 period, with the strongest trends for the Eurasian Arctic, Barents Sea, Greenland Sea, and North Atlantic. 3. The regional distribution of relatively high (low) chlorophyll-a concentrations can often be associated with a relatively early (late) breakup of sea ice cover

Developing an observational design for epibenthos and fish assemblages in the Chukchi Sea

Accepted manuscript version, licensed CC BY-NC-ND 4.0. Published version available at https://doi.org/10.1016/j.dsr2.2018.11.005.In light of ongoing, and accelerating, environmental changes in the Pacific sector of the Arctic Ocean, the ability to track subsequent changes over time in various marine ecosystem components has become a major research goal. The high logistical efforts and costs associated with arctic work demand the prudent use of existing resources for the most comprehensive information gain. Here, we compare the information that can be gained for epibenthic invertebrate and for demersal fish assemblages reflecting coverage on two different spatial scales: a broader spatial coverage from the Arctic Marine Biodiversity Observing Network (AMBON, 67 stations total), and the spatial coverage from a subset of these stations (14 stations) that reflect two standard transect lines of the Distributed Biological Observatory (DBO). Multivariate cluster analysis was used to discern community similarity patterns in epibenthic invertebrate and fish communities. The 14 stations reflecting the two DBO lines captured about 57% of the epibenthic species richness that was observed through the larger-scale AMBON coverage, with a higher percentage on the more southern DBO3 than the northern DBO4 line. For demersal fishes, both DBO lines captured 88% of the richness from the larger AMBON spatial coverage. The epifaunal assemblage clustered along the south-north and the inshore-offshore axes of the overall study region. Of these, the southern DBO3 line well represented the regional (southern) epifaunal assemblage structure, while the northern DBO4 line only captured a small number of the distinct assemblage clusters. The demersal fish assemblage displayed little spatial structure with only one coastal and one offshore cluster. Again, this structure was well represented by the southern DBO3 line but less by the northern DBO4 line. We propose that extending the coverage of the DBO4 line in the northern Chukchi Sea farther inshore and offshore would result in better representation of the overall northern Chukchi epifaunal and fish assemblages. In addition, the multi-annual stability of epifaunal and, to a lesser extent also fish assemblages, suggests that these components may not need to be sampled on an annual basis and sampling every 2–3 years could still provide sufficient understanding of long-term changes. Sampling these assemblages every few years from a larger region such as covered by the AMBON project would create the larger-scale context that is important in spatial planning of long-term observing

Walruses Attack Spectacled Eiders Wintering in Pack Ice of the Bering Sea

We observed walruses (Odobenus rosmarus) pursuing spectacled eiders (Somateria fischeri) within pack ice of the Bering Sea, 70–90 km from the nearest land. We used both direct observations from a helicopter and a heligimbal camera system that can film animals from a helicopter at high altitudes. The eiders were in monospecific flocks of thousands of birds within large leads. The walruses apparently tried to catch the eiders from below; the eiders responded with a “flash expansion” (explosive radial movement), wing-flapping and running along the water surface to escape. Disturbance by individual walruses could restrict flocks of thousands of birds to small portions of the open water. In eight such events that we witnessed over 75 min of observations, we were unable to confirm that walruses captured any of these full-grown, flight-capable eiders. However, the high rate of attacks and the eiders’ dramatic escape response suggest that walruses can at times be effective predators on them, and may affect the eiders’ dispersion and energy balance.Nous avons observé des morses (Odobenus rosmarus) en train de pourchasser des eiders à lunettes (Somateria fischeri) sur la banquise de la mer de Béring, soit à une distance de 70 à 90 kilomètres de la terre ferme la plus près. Nous nous sommes servis à la fois d’observations directes faites à partir d’un hélicoptère et d’un appareil héligimbal capable de filmer les animaux à partir d’un hélicoptère à haute altitude. Les eiders se tenaient en bandes monospécifiques constituées de milliers d’oiseaux faisant partie de gros groupements. Il semblait que les morses essayaient d’attraper les eiders par en-dessous; les eiders réagissaient en faisant une « expansion éclair » (un mouvement radial explosif), en battant des ailes et en courant le long de la surface de l’eau afin de s’échapper. Les perturbations exercées par les morses individuels pouvaient avoir pour effet de restreindre les bandes de milliers d’oiseaux à de petites nappes d’eau libre. Dans huit cas de telle nature dont nous avons été témoins pendant plus de 75 minutes d’observation, nous n’avons pas été en mesure de confirmer si les morses avaient réussi à capturer des eiders adultes en état de voler. Cependant, le taux élevé d’attaques de même que la réaction dramatique des eiders qui tentaient de s’échapper laissent entrevoir que les morses pourraient être des prédateurs efficaces en ce qui les concerne, ce qui pourrait exercer une influence sur l’expansion des eiders et sur leur bilan énergétique

Linkages among runoff, dissolved organic carbon, and the stable oxygen isotope composition of seawater and other water mass indicators in the Arctic Ocean

Author Posting. © American Geophysical Union, 2005. 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 110 (2005): G02013, doi:10.1029/2005JG000031.Concentrations of dissolved organic carbon (DOC) and δ18O values have been determined following sampling of runoff from a number of major arctic rivers, including the Ob, Yenisey, Lena, Kolyma, Mackenzie and Yukon in 2003-2004. These data are considered in conjunction with marine data for DOC, δ18O values, nutrients, salinity, and fluorometric indicators of DOC that were obtained as part of the Shelf-Basin Interactions program at the continental shelf-basin boundary of the Chukchi and Beaufort Seas. These marine data indicate that the freshwater component is most likely derived from regional sources, such as the Mackenzie, the Bering Strait inflow and possibly eastern Siberian rivers, including the Kolyma, or the Lena but not rivers further west in the Eurasian arctic. Contributions of freshwater from melted sea ice to marine surface waters appeared to be insignificant over annual cycles compared to runoff, although on a seasonal basis, freshwater from melted sea ice was locally dominant following a major sea-ice retreat into the Canada Basin in 2002. DOC concentrations were correlated with the runoff fraction, with an apparent meteoric water DOC concentration of 174 ± 1 μM (standard error). This concentration is lower than the flow-weighted concentrations measured at river mouths of the five largest Arctic rivers (358 to 917 μM), indicating that removal of terrigenous DOC during transport through estuaries, shelves and in the deep basin. DOC data indicate that flow-weighted concentrations in the two largest North American arctic rivers, the Yukon (625μM) and the Mackenzie (382 μM), are lower than in the three largest Eurasian arctic rivers, the Ob (825 μM), the Yenesey (858 μM) and the Lena (917 μM). A fluorometric indicator of chromophoric dissolved organic matter (CDOM) that has provided estimates of terrigenous DOC concentrations in the Eurasian Arctic was not correlated with DOC concentrations in the Amerasian marine waters studied, except below the upper Arctic Ocean halocline. Nutrient distributions and concentrations as well as derived nutrient ratios suggest the CDOM fluorometer may be responding to the release of chromophoric materials from continental shelf sediments. Shipboard incubation experiments with undisturbed sediment cores indicate that continental shelf sediments on the Bering and Chukchi Sea shelves are likely to be a net source of DOC to the Arctic Ocean.The PARTNERS and SBI projects have been supported by the Office of Polar Programs of the U.S. National Science Foundation

Monitoring Alaskan Arctic shelf ecosystems through collaborative observation networks

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Danielson, S. L., Grebmeier, J. M., Iken, K., Berchok, C., Britt, L., Dunton, K. H., Eisner, L., V. Farley, E., Fujiwara, A., Hauser, D. D. W., Itoh, M., Kikuchi, T., Kotwicki, S., Kuletz, K. J., Mordy, C. W., Nishino, S., Peralta-Ferriz, C., Pickart, R. S., Stabeno, P. S., Stafford. K. M., Whiting, A. V., & Woodgate, R. Monitoring Alaskan Arctic shelf ecosystems through collaborative observation networks. Oceanography, 35(2), (2022): 52, https://doi.org/10.5670/oceanog.2022.119.Ongoing scientific programs that monitor marine environmental and ecological systems and changes comprise an informal but collaborative, information-rich, and spatially extensive network for the Alaskan Arctic continental shelves. Such programs reflect contributions and priorities of regional, national, and international funding agencies, as well as private donors and communities. These science programs are operated by a variety of local, regional, state, and national agencies, and academic, Tribal, for-profit, and nongovernmental nonprofit entities. Efforts include research ship and autonomous vehicle surveys, year-long mooring deployments, and observations from coastal communities. Inter-program coordination allows cost-effective leveraging of field logistics and collected data into value-added information that fosters new insights unattainable by any single program operating alone. Coordination occurs at many levels, from discussions at marine mammal co-management meetings and interagency meetings to scientific symposia and data workshops. Together, the efforts represented by this collection of loosely linked long-term monitoring programs enable a biologically focused scientific foundation for understanding ecosystem responses to warming water temperatures and declining Arctic sea ice. Here, we introduce a variety of currently active monitoring efforts in the Alaskan Arctic marine realm that exemplify the above attributes.Funding sources include the following: ALTIMA: BOEM M09PG00016, M12PG00021, and M13PG00026; AMBON: NOPP-NA14NOS0120158 and NOPP-NA19NOS0120198; Bering Strait moorings: NSF-OPP-AON-PLR-1758565, NSF-OPP-PLR-1107106; BLE-LTER: NSF-OPP-1656026; CEO: NPRB-L36, ONR N000141712274 and N000142012413; DBO: NSF-AON-1917469 and NOAA-ARP CINAR-22309.07; HFR, AOOS Arctic glider, and Passive Acoustics at CEO and Bering Strait: NA16NOS0120027; WABC: NSF-OPP-1733564. JAMSTEC: partial support by ArCS Project JPMXD1300000000 and ArCS II Project JPMXD1420318865; Seabird surveys: BOEM M17PG00017, M17PG00039, and M10PG00050, and NPRB grants 637, B64, and B67. This publication was partially funded by the Cooperative Institute for Climate, Ocean, & Ecosystem Studies (CICOES) under NOAA Cooperative Agreement NA20OAR4320271, and represents contribution 2021-1163 to CICOES, EcoFOCI-1026, and 5315 to PMEL. This is NPRB publication ArcticIERP-43

CASCADE-The Circum-Arctic Sediment CArbon DatabasE

Biogeochemical cycling in the semi-enclosed Arctic Ocean is strongly influenced by land–ocean transport of carbon and other elements and is vulnerable to environmental and climate changes. Sediments of the Arctic Ocean are an important part of biogeochemical cycling in the Arctic and provide the opportunity to study present and historical input and the fate of organic matter (e.g., through permafrost thawing). Comprehensive sedimentary records are required to compare differences between the Arctic regions and to study Arctic biogeochemical budgets. To this end, the Circum-Arctic Sediment CArbon DatabasE (CASCADE) was established to curate data primarily on concentrations of organic carbon (OC) and OC isotopes (δ13C, Δ14C) yet also on total N (TN) as well as terrigenous biomarkers and other sediment geochemical and physical properties. This new database builds on the published literature and earlier unpublished records through an extensive international community collaboration. This paper describes the establishment, structure and current status of CASCADE. The first public version includes OC concentrations in surface sediments at 4244 oceanographic stations including 2317 with TN concentrations, 1555 with δ13C-OC values and 268 with Δ14C-OC values and 653 records with quantified terrigenous biomarkers (high-molecular-weight n-alkanes, n-alkanoic acids and lignin phenols). CASCADE also includes data from 326 sediment cores, retrieved by shallow box or multi-coring, deep gravity/piston coring, or sea-bottom drilling. The comprehensive dataset reveals large-scale features of both OC content and OC sources between the shelf sea recipients. This offers insight into release of pre-aged terrigenous OC to the East Siberian Arctic shelf and younger terrigenous OC to the Kara Sea. Circum-Arctic sediments thereby reveal patterns of terrestrial OC remobilization and provide clues about thawing of permafrost. CASCADE enables synoptic analysis of OC in Arctic Ocean sediments and facilitates a wide array of future empirical and modeling studies of the Arctic carbon cycle. The database is openly and freely available online (https://doi.org/10.17043/cascade; Martens et al., 2021), is provided in various machine-readable data formats (data tables, GIS shapefile, GIS raster), and also provides ways for contributing data for future CASCADE versions. We will continuously update CASCADE with newly published and contributed data over the foreseeable future as part of the database management of the Bolin Centre for Climate Research at Stockholm University

What Happened to Gray Whales during the Pleistocene? The Ecological Impact of Sea-Level Change on Benthic Feeding Areas in the North Pacific Ocean

Gray whales (Eschrichtius robustus) undertake long migrations, from Baja California to Alaska, to feed on seasonally productive benthos of the Bering and Chukchi seas. The invertebrates that form their primary prey are restricted to shallow water environments, but global sea-level changes during the Pleistocene eliminated or reduced this critical habitat multiple times. Because the fossil record of gray whales is coincident with the onset of Northern Hemisphere glaciation, gray whales survived these massive changes to their feeding habitat, but it is unclear how.We reconstructed gray whale carrying capacity fluctuations during the past 120,000 years by quantifying gray whale feeding habitat availability using bathymetric data for the North Pacific Ocean, constrained by their maximum diving depth. We calculated carrying capacity based on modern estimates of metabolic demand, prey availability, and feeding duration; we also constrained our estimates to reflect current population size and account for glaciated and non-glaciated areas in the North Pacific. Our results show that key feeding areas eliminated by sea-level lowstands were not replaced by commensurate areas. Our reconstructions show that such reductions affected carrying capacity, and harmonic means of these fluctuations do not differ dramatically from genetic estimates of carrying capacity.Assuming current carrying capacity estimates, Pleistocene glacial maxima may have created multiple, weak genetic bottlenecks, although the current temporal resolution of genetic datasets does not test for such signals. Our results do not, however, falsify molecular estimates of pre-whaling population size because those abundances would have been sufficient to survive the loss of major benthic feeding areas (i.e., the majority of the Bering Shelf) during glacial maxima. We propose that gray whales survived the disappearance of their primary feeding ground by employing generalist filter-feeding modes, similar to the resident gray whales found between northern Washington State and Vancouver Island

Upwelling on the continental slope of the Alaskan Beaufort Sea : storms, ice, and oceanographic response

Author Posting. © American Geophysical Union, 2009. 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 114 (2009): C00A13, doi:10.1029/2008JC005009.The characteristics of Pacific-born storms that cause upwelling along the Beaufort Sea continental slope, the oceanographic response, and the modulation of the response due to sea ice are investigated. In fall 2002 a mooring array located near 152°W measured 11 significant upwelling events that brought warm and salty Atlantic water to shallow depths. When comparing the storms that caused these events to other Aleutian lows that did not induce upwelling, interesting trends emerged. Upwelling occurred most frequently when storms were located in a region near the eastern end of the Aleutian Island Arc and Alaskan Peninsula. Not only were these storms deep but they generally had northward-tending trajectories. While the steering flow aloft aided this northward progression, the occurrence of lee cyclogenesis due to the orography of Alaska seems to play a role as well in expanding the meridional influence of the storms. In late fall and early winter both the intensity and frequency of the upwelling diminished significantly at the array site. It is argued that the reduction in amplitude was due to the onset of heavy pack ice, while the decreased frequency was due to two different upper-level atmospheric blocking patterns inhibiting the far field influence of the storms.The following grants provided support for this study: National Science Foundation grants OPP-0731928 (R.S.P.) and OPP-0713250 (R.S.P. and P.S.F.), Office of Naval Research grant N00014-07-1-1040 (D.J.T. and R.A.G.), Natural Sciences and Engineering Research Council of Canada (G.W.K.M.), Woods Hole Oceanographic Institution Arctic Initiative (J.Y.)

Securing ocean benefits for society in the face of climate change

Benefits humans rely on from the ocean - marine ecosystem services - are increasingly vulnerable under future climate. This paper reviews how three valued services have, and will continue to, shift under climate change: (1) capture fisheries, (2) food from aquaculture, and (3) protection from coastal hazards such as storms and sea-level rise. Climate adaptation planning is just beginning for fisheries, aquaculture production, and risk mitigation for coastal erosion and inundation. A few examples are highlighted, showing the promise of considering multiple ecosystem services in developing approaches to adapt to sea-level rise, ocean acidification, and rising sea temperatures. Ecosystem-based adaptation in fisheries and along coastlines and changes in aquaculture practices can improve resilience of species and habitats to future environmental challenges. Opportunities to use market incentives - such as compensation for services or nutrient trading schemes - are relatively untested in marine systems. Relocation of communities in response to rising sea levels illustrates the urgent need to manage human activities and investments in ecosystems to provide a sustainable flow of benefits in the face of future climate change. (C) 2013 Elsevier Ltd. All rights reserved

From sea ice to seals: a moored marine ecosystem observatory in the Arctic

Although Arctic marine ecosystems are changing rapidly, year-round monitoring is currently very limited and presents multiple challenges unique to this region. The Chukchi Ecosystem Observatory (CEO) described here uses new sensor technologies to meet needs for continuous, high-resolution, and year-round observations across all levels of the ecosystem in the biologically productive and seasonally ice-covered Chukchi Sea off the northwest coast of Alaska. This mooring array records a broad suite of variables that facilitate observations, yielding better understanding of physical, chemical, and biological couplings, phenologies, and the overall state of this Arctic shelf marine ecosystem. While cold temperatures and 8 months of sea ice cover present challenging conditions for the operation of the CEO, this extreme environment also serves as a rigorous test bed for innovative ecosystem monitoring strategies. Here, we present data from the 2015–2016 CEO deployments that provide new perspectives on the seasonal evolution of sea ice, water column structure, and physical properties, annual cycles in nitrate, dissolved oxygen, phytoplankton blooms, and export, zooplankton abundance and vertical migration, the occurrence of Arctic cod, and vocalizations of marine mammals such as bearded seals. These integrated ecosystem observations are being combined with ship-based observations and modeling to produce a time series that documents biological community responses to changing seasonal sea ice and water temperatures while establishing a scientific basis for ecosystem management.</p