Kernel Density Analysis and Mapping of Ecosystem Functions in the NAFO Regulatory Area

In support of the 2021/2022 NAFO review of the closed areas to protect vulnerable marine ecosystems (VMEs) in the NAFO Regulatory Area, previously established kernel density estimation (KDE) methods were applied to four important ecological functions provided by benthic communities: A) Bioturbation; B) Nutrient cycling; C) Habitat provision; and D) Functional diversity (FRic), in order to evaluate significant adverse impacts of NAFO bottom-contact fishing on vulnerable marine ecosystems against the wider benthic contributions to those functions. Fish and invertebrate species recorded in the EU and Canadian surveys from 2011-2019 were classified a priori as contributing to each of bioturbation, nutrient cycling and habitat provision functions, using literature references. The resultant catch biomass data for each function were examined using K-S statistics and cumulative biomass distribution plots to determine whether data from the different surveys could be combined. With few exceptions the surveys were analyzed separately and the KDE polygons overlain a posteriori to produce combined polygon areas for each function. A suite of species were important contributors to the biomass of catches used to delineate each of the KDE polygons. For bioturbation, the sea cucumber Cucumaria frondosa and sea pens, both considered surficial modifiers, contributed most to the biomass. Nutrient cycling and habitat provision functions were delineated by catches where sponges dominated the biomass. Details of the analyses and the species that contributed to the delineation of the polygons are provided. Functional diversity was not assessed as information needed on a wide variety of traits and modalities was not completed. However published data from a survey in 2007 of Division 3M was used to run the KDE analyses with equivocal results. The KDE polygons generated matched published maps of FRic created using the same data and interpolated using random forest modeling. However the data were not sufficiently aggregated to allow for a clear KDE threshold to be determined. All other KDE analyses performed well and showed good congruence to the published maps of their corresponding functions.Versión del editor

The Effects of the Endicott Development Project on the Boulder Patch, an Arctic Kelp Community in Stefansson Sound, Alaska

The Boulder Patch in Stefansson Sound, Beaufort Sea, of Alaska harbors a diverse arctic kelp community in areas where rock cover exceeds 10%. In 1985, the Endicott Development Project, the first major offshore oil development in the Alaskan Arctic, was constructed shoreward of this community at the mouth of the Sagavanirktok River. A 7-year study was conducted to determine the effects of the development on kelp health and growth and taxa diversity of the overall community. No adverse effects were detected. The regional patterns of sediment transport served to protect the community from development-derived sediment loadings and discharges. Sediment transport patterns likely also contribute to the unusual presence of this community in the sound.Key words: Boulder Patch, kelp, Laminaria solidungula, Beaufort Sea, productivity, colonization, epilithic community, epilithic flora, epilithic fauna, benthic community, sediment transportBoulder Patch, dans le détroit Stefansson situé dans la mer de Beaufort (Alaska), abrite une communauté d'algues diversifiée dans les endroits où la couverture rocheuse dépasse 10 p. cent. En 1985 a été lancé le projet de développement d'Endicott, premier grand aménagement d'exploitation pétrolière en mer dans l'Arctique alaskien, établi entre le rivage et cette communauté, à l'embouchure de la rivière Sagavanirktok. Une étude de sept ans a été menée pour déterminer les effets du développement sur l'état de santé et la croissance des algues ainsi que sur la diversité des taxons de l'ensemble de la communauté. Aucun effet nocif n'a été détecté. Les schémas régionaux du transport sédimentaire ont servi à protéger la communauté de l'accumulation et du débit sédimentaires dus à l'exploitation. Les schémas de transport des sédiments ont aussi probablement contribué à la présence inhabituelle de cette communauté dans le détroit.Mots clés: Boulder Patch, algues, Laminaria solidungulam, mer de Beaufort, productivité, colonisation, communauté épilithique, flore épilithique, faune épilithique, communauté benthique, transsrt solid

Predicting the Distribution of Indicator Taxa of Vulnerable Marine Ecosystems in the Arctic and Sub-arctic Waters of the Nordic Seas

publishedVersio

Weak seasonality in benthic food web structure within an Arctic inflow shelf region

The Arctic Ocean is characterized by pronounced seasonality in the quantity and quality of organic matter exported from the surface ocean. While it is well established that changes in food availability can alter the abundance, biomass and function of benthic organisms, the impact on food web structure is not well studied. We used bulk carbon and nitrogen stable isotope analysis to assess the quantity and quality of sediment organic matter and structure of the benthic food web in four seasons within the Northern Barents Sea (76°N − 82 °C). Despite a highly seasonal vertical flux, we found that the organic carbon and chlorophyll-a content of surface sediments was seasonally stable, suggesting a lack of seasonality in food availability at the seafloor. However, organic biomarkers indicate that the quality of sediment organic matter increased to a maximum in August and December, up to 6 months after the spring bloom. The seasonal stability of food quantity was mirrored in food-web structure (e.g., total isotopic range, number of trophic levels) which did not change significantly across sampling periods. We expected that suspension and deposit feeders would respond more readily to seasonal changes in food quality compared to predators. However, we observed no significant seasonal changes in the trophic levels or isotopic niche areas of benthic functional groups. The centroids of isotopic niches of all benthic functional groups shifted seasonally by <2 ‰ along the δ13C-axis, suggesting minimal shifts in carbon resource use. Because the northern Barents Sea experiences significant changes in seasonal sea ice cover, we expected that stable-isotope ratios of benthic organisms would show an increased consumption of sympagic-derived organic matter through less negative δ13C values in early spring and summer. However, only two taxa (the soft coral Gersemia spp. and bivalves in the family Yoldiidae) showed 13C-enrichment in spring or summer consistent with the assimilation of sympagic-derived organic matter, despite previous evidence suggesting widespread use of this carbon source. Overall, our results show that there is an apparent de-coupling in time between pelagic processes and benthic food-webs in which the accumulation and assimilation of high-quality organic matter occurs for benthos during the fall and early winter months when there is little to no fresh organic matter generated at the surface. This temporal mismatch highlights the importance of considering the timescales over which components of the marine ecosystem respond to short-term environmental changes and the methods employed to assess seasonality.Weak seasonality in benthic food web structure within an Arctic inflow shelf regionpublishedVersio

Trophic dynamics in marine nearshore systems of the Alaskan high arctic

Thesis (Ph.D.) University of Alaska Fairbanks, 198

Dynamic benthic communities: assessing temporal variations in benthic community structure, megafaunal composition and diversity at the Arctic deep-sea observatory HAUSGARTEN between 2004 and 2015

Established in the Fram Strait in 1999, the LTER (Long-Term Ecological Research) observatory HAUSGARTEN enables us to study changes on the deep Arctic seafloor. Repeated deployments of a towed camera system (Ocean Floor Observation System) along the same tracks allowed us to build a time series longer than a decade (2004 - 2015). Here, we present the first time-series results from a northern and the southernmost station of the observatory (N3 and S3, ~2650m and 2350m depth respectively) obtained via the analysis of still imagery. We assess temporal variability in community structure, megafaunal densities and diversity, and use a range of biotic and abiotic factors to explain the patterns observed. There were significant temporal differences in megafaunal abundances, diversity and abiotic factors at both stations. A particularly high increase in megafaunal abundance was recorded at N3 from 12.08 (±0.39; 2004) individuals m-2 to 35.21 (±0.97; 2007) ind. m-2 alongside a ten-fold increase in (drop-)stones. At S3, megafaunal densities peaked in 2015 (22.74 ±0.61 ind. m-2) after an increasing trend since 2004 (12.44 ±0.32 ind. m-2). Holothurians showed particularly striking temporal differences: densities of the small sea cucumber Elpidia heckeri densities rose ten-fold from 0.31 ind. m-2 (±0.04; 2004) to 3.74 ind. m-2 (±0.14; 2015) at S3, coinciding with a sustained increase in phytodetritial matter (chloroplastic pigment equivalents) at the seafloor. Initially entirely absent from N3, densities of the larger holothurian Kolga hyalina peaked in 2007 (5.87 ±0.22 ind. m-2) and declined continuously since then. Overall diversity (γ) increased at both stations over the course of the study, however, with varying contributions of α and β diversities. Our results highlight the importance of time-series studies as megafaunal community composition is characterised by continuous changes. This indicates that epibenthic communities from the deep seafloor are reactive and dynamic, with no “null” community state. To continue to monitor them is therefore crucial in understanding natural and anthropogenic impacts in an area exposed to the effects of climate change

List of Species as recorded by Canadian and EU Bottom Trawl Surveys in Flemish Cap

A list of species has been prepared with all records in each haul of both Canadian (1977-1985) and EU (1988-2002 and 2003-2012) bottom trawl surveys. Even though sampling intensity and taxonomic interest changed with time, the three periods can be considered almost homogeneous. Main change occurred when the EU survey increased the depth range, from 730 to 1460 meters depth, and all invertebrates were recorded

Predation by the nudibranch Tritonia odhneri (Opisthobranchia: Tritoniidae) on octocorals from the South Atlantic Ocean

The diet of the nudibranch mollusc Tritonia odhneri was investigated for the first time based on a detailed anatomical analysis of the gut content of 52 specimens. Digestive tracts of specimens were analysed under stereoscopic microscope equipped with digital camera. Portions of octocorals containing the calcareous sclerites were removed from the tracts and prepared for scanning electron microscopy (SEM). Sclerite morphology and size were determined at the species and genus level on the basis of a taxonomical revision and compared with fresh octocoral specimens collected from Patagonia (San Jorge Gulf) and with voucher specimens from the collections of Museo Argentino de Ciencias Naturales (MACN-in). Specific predation of T. odhneri on octocoral species present in the southwestern Atlantic Ocean was detected. The nudibranch feeds on the gorgonians Primnoella divaricata, Primnoella scotiae (=P. compressa) and Tripalea clavaria, and the pennatulaceans Renilla octodentata and Stylatula sp. A world checklist of dietary interactions between species of the genus Tritonia and octocorals is presented and discussed.Fil: García Matucheski, Stella. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Muniain, Claudia Cristina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin

List of Species as recorded by Canadian and EU Bottom Trawl Surveys in Flemish Cap

13 páginas, 1 tabla.-- Scientific Council MeetingA list of species has been prepared with all records in each haul of both Canadian (1977-1985) and EU (1988-2002 and 2003-2012) bottom trawl surveys. Even though sampling intensity and taxonomic interest changed with time, the three periods can be considered almost homogeneous. Main change occurred when the EU survey increased the depth range, from 730 to 1460 meters depth, and all invertebrates were recorded.Peer reviewe