Spatial and temporal patterns in the Gulf of Alaska groundfish community in relation to the environment

Thesis (Ph.D.) University of Alaska Fairbanks, 1999The GoA supports a rich demersal fish community dominated by gadids, pleuronectids, sablefish (Anoplopoma fimbria) and rockfishes (Sebastes spp.). This study describes the structure of the juvenile and adult groundfish communities of the Gulf of Alaska (GoA) in relation to their environment and along spatial and temporal gradients. Abundance data were obtained from trawl surveys of juvenile groundfishes in the nearshore areas of Kodiak Island (1991--1996), shrimp-trawl surveys in the same areas (1976--1995), and triennial bottom trawl surveys of adult groundfishes on the GoA shelf and upper slope (1984--1996). Species richness, species diversity, total abundance, and multivariate indices of species composition for each station sampled were statistically related to depth, temperature, salinity, sediment composition, geographic location, and time of sampling to identify spatial and temporal patterns in community structure. The observed patterns were then related to local and large-scale atmospheric and oceanographic trends. Both juvenile and adult groundfish communities were primarily structured along the depth gradient. The abundance of juvenile groundfishes decreased with depth from 0 to 100m, whereas the abundance of adults increased with depth to a peak at 150--200m. Species richness and diversity of the adult community had a significant peak at 200--300m. Spatial patterns suggested higher abundances, lower species richness and diversity, and a different species composition of demersal fishes in the western GoA compared to the eastern GoA. These large-scale spatial patterns appear to be related to differences in upwelling between the eastern and western GoA. A 40% increase in total groundfish biomass on the GoA shelf and upper slope was estimated between 1984 and 1996. Significant changes in species composition occurred in the nearshore areas of Kodiak Island in the early 1980s, from a community dominated by shrimp and small forage fishes to one dominated by large piscivorous gadids and flatfishes. The change in species composition in the nearshore community appeared to be linked to an increase in advection in the Alaska Current. Increased flow around the GoA may enhance the supply of nutrients and plankton on the shelf and upper slope, resulting in an increase in overall productivity of the pelagic and demersal biota

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

Possible future scenarios for two major Arctic Gateways connecting Subarctic and Arctic marine systems: I. Climate and physical-chemical oceanography

We review recent trends and projected future physical and chemical changes under climate change in transition zones between Arctic and Subarctic regions with a focus on the two major inflow gateways to the Arctic, one in the Pacific (i.e. Bering Sea, Bering Strait, and the Chukchi Sea) and the other in the Atlantic (i.e. Fram Strait and the Barents Sea). Sea-ice coverage in the gateways has been disappearing during the last few decades. Projected higher air and sea temperatures in these gateways in the future will further reduce sea ice, and cause its later formation and earlier retreat. An intensification of the hydrological cycle will result in less snow, more rain, and increased river runoff. Ocean temperatures are projected to increase, leading to higher heat fluxes through the gateways. Increased upwelling at the Arctic continental shelf is expected as sea ice retreats. The pH of the water will decline as more atmospheric CO2 is absorbed. Long-term surface nutrient levels in the gateways will likely decrease due to increased stratification and reduced vertical mixing. Some effects of these environmental changes on humans in Arctic coastal communities are also presented.publishedVersio

A Decade of Incorporating Social Sciences in the Integrated Marine Biosphere Research Project (IMBeR): Much Done, Much to Do?

Successful management and mitigation of marine challenges depends on cooperation and knowledge sharing which often occurs across culturally diverse geographic regions. Global ocean science collaboration is therefore essential for developing global solutions. Building effective global research networks that can enable collaboration also need to ensure inter- and transdisciplinary research approaches to tackle complex marine socio-ecological challenges. To understand the contribution of interdisciplinary global research networks to solving these complex challenges, we use the Integrated Marine Biosphere Research (IMBeR) project as a case study. We investigated the diversity and characteristics of 1,827 scientists from 11 global regions who were attendees at different IMBeR global science engagement opportunities since 2009. We also determined the role of social science engagement in natural science based regional programmes (using key informants) and identified the potential for enhanced collaboration in the future. Event attendees were predominantly from western Europe, North America, and East Asia. But overall, in the global network, there was growing participation by females, students and early career researchers, and social scientists, thus assisting in moving toward interdisciplinarity in IMBeR research. The mainly natural science oriented regional programmes showed mixed success in engaging and collaborating with social scientists. This was mostly attributed to the largely natural science (i.e., biological, physical) goals and agendas of the programmes, and the lack of institutional support and push to initiate connections with social science. Recognising that social science research may not be relevant to all the aims and activities of all regional programmes, all researchers however, recognised the (potential) benefits of interdisciplinarity, which included broadening scientists’ understanding and perspectives, developing connections and interlinkages, and making science more useful. Pathways to achieve progress in regional programmes fell into four groups: specific funding, events to come together, within-programme-reflections, and social science champions. Future research programmes should have a strategic plan to be truly interdisciplinary, engaging natural and social sciences, as well as aiding early career professionals to actively engage in such programmes.This publication resulted in part from support from the U.S. National Science Foundation (Grant OCE-1840868) to the Scientific Committee on Oceanic Research (SCOR)

Technically advanced and SF6-free 145 kV blue GIS

SF6, the most commonly used arc extinguishing and insulating gas in gas-insulated switchgears (GIS), is a greenhouse gas with high global warming potential, requiring careful handling throughout its life cycle. In order to reduce the GIS-related global warming impact, innovative solutions using alternative gases have been developed by different manufacturers, especially the blue GIS from Siemens – available for 145 kV / 40 kA / 3150 A – with clean air insulation and vacuum switching technology shows many technical advantages

Appendix B. Evaluating climate effects on distribution of individual taxa.

Evaluating climate effects on distribution of individual taxa

Comparison of 4 Northern Hemisphere regions: Ecosystem responses to recent oceanographic variability

Ecosystem responses to oceanographic variability resulting from recent climate changes are compared and contrasted for four high latitude regions of the Northern Hemisphere, two in the Pacific (Bering Sea and Gulf of Alaska) and two in the Atlantic (Georges Bank/Gulf of Maine and the Barents/Norwegian Seas). Changes in nutrient content and its effect on phytoplankton biomass and production are compared among systems and recent trends towards smaller zooplankton in the Bering Sea and in the Georges Bank region are evaluated. In each of the regions, several fish species show a general poleward movement in response to the warming, as well as more complex, non-linear responses resulting from internal community dynamics and fishing. Observed changes in the abundance, individual growth and species composition of the fish communities are assessed in terms of environmental and fishing effects. Changes in marine mammals and seabirds in the four regions are documented. Comparisons between the different regions are made to identify and distinguish general responses from regionally unique responses. This is a contribution from the Comparison of Marine Ecosystems of Norway and the US (MENU) project

Appendix A. Quantifying spatial patterns in community characteristics and estimating latitudinal and depth gradients in catch per unit effort (CPUE) and probability of occurrence using generalized additive models.

Quantifying spatial patterns in community characteristics and estimating latitudinal and depth gradients in catch per unit effort (CPUE) and probability of occurrence using generalized additive models