This report summarizes the workshop sponsored by the Integrating Climate and Ecosystem Dynamics in the Southern Ocean program (ICED). The workshop, held from 17-20 May 2021, was focussed on improving our modeling of Antarctic krill and strengthening connections between the krill modeling community, the SCAR Krill Action Group (SKAG) and the scientists involved in CCAMLR (particularly WG-EMM). Workshop attendees represented a broad cross-section of the international krill modeling community, in addition to researchers focussed on other species, comprising ~80 registered participants across all career stages. The workshop included a background session and three themed sessions focussing on key aspects of krill modeling. The workshop also aimed to provide Early Career Researchers (ECRs) with opportunities to network and highlight their work, as part of ICED’s wider goal of including ECRs in ICED activities to foster career development and shape the future of ICED research. This paper presents the initial findings for research priorities, data requirements, facilitation methods for integrating modeling approaches, and ideas on fostering research networks and involvement within the Antarctic krill modeling community and beyond.

Distribution pattern of living resources is spatial scale-dependence, therefore an inappropriate scale may produce misleading results. As a key species in the Antarctic ecosystem, distribution of Antarctic krill (Euphausia superba) demonstrates significant spatial-temporal heterogeneity. The distribution pattern of this species is spatiotemporal complex and cannot be predicted effectively. In order to understand the spatial-temporal distribution pattern of krill resource in the Antarctic Peninsula, an important ecological and commercial-interested regions, the Moran's I value of krill density distribution was calculated at 12 spatial scales (5'×5' - 60'×60') by 5' grid of latitude and longitude. The results showed that the spatial pattern of krill is differed in spatial scales. The distribution of krill density showed a discrete trend at the 25'×25' scale, but the distribution of krill density showed a clustering trend at the other 11 spatial scales. According to the correlogram between the Moran's I value and spatial scale, the characteristic spatial scales of krill density distribution were determined as about 25'×25', which was determined by the Moran's I value inter-crossing the x-axis for the first time, and 15'×15', which was determined by the smallest scale with no significant difference between the Moran's I value and zero in the correlogram, respectively. This study showed that the method with no significant difference between the Moran's I value and zero value was more consistent with the characteristics of krill resource. It was, therefore, recommended that 15'×15' could be the optimum spatial scale for analyzing the distribution of krill density in this region.

Based on the results of RV Atlantida cruise in January - March 2020 in Subareas 48.1 and 48.2  data on the structure, quantitative indicators and spatial distribution of phytoplankton and zooplankton (species composition, abundance, biomass), primary production phytoplankton, chlorophyll concentration were obtained. Sampling stations were located above depths of 82 - 4300 m. Chlorophyll was studied at 180 stations, zooplankton and phytoplankton at 66 stations, and primary production at 66 stations. Phytoplankton during the summer period was represented by 120 identified species, mainly diatoms.  In the entire  study area, 4 phytoplankton communities were identified, which has different biotope conditions, spatial distribution and complex of the main structure-forming species. Zooplankton was represented by 53 species, mainly copepods. High correlations of surface concentration of chlorophyll a with the abundance and biomass of phytoplankton, primary production and chlorophyll content on average and integral for the photosynthesis zone have been obtained, which makes it possible to use remote satellite observations for assessments of abundance and productivity of phytoplankton as the basis of food chains, including krill, in the Atlantic sector of the Southern Ocean. Phytoplankton and zooplankton data are essential components for further analysis with the spatial distribution of environmental conditions and krill abundance to identify the relationships that determine ecosystem dynamics in the Antarctic sector of the Southern Ocean.

Results of observations of seabirds and mammals obtained during the acoustic survey in the Subarea 48.1 and 48.2 in January-March 2020 onboard the RV “ATLANTIDA” are presented  Seabirds were represented by 27 species. Marine mammals were represented by thirteen species of marine mammals.  Ten species belonged to cetaceans, three species belonged to the group of pinnipeds (carnivora).  Distribution of abundance of seabird and mammal in relation to krill density  is shown.

Ardley Island, in the Fildes Region, southwest of King George Island, South Shetland Islands, is an Antarctic Specially Protected Area (ASPA N° 150) and is one of the few areas in Antarctica where the three Pygoscelis penguin species (Adélie, Chinstrap and Gentoo) breed sympatrically. Since the 1980s, a research group from the University of Jena, Germany, has been monitoring the breeding pairs and breeding success of three penguin species. The numbers of breeding pairs of Chinstrap penguins have decreased by more than 90% since counts began in the 80s, and more than 30% for Adelie penguins. In contrast, Gentoo penguins increased over the same period by more than 80% During the 2019-2020 summer campaign, as part of a CCAMLR Scientific Scholarship Scheme project, a collaboration with the University of Jena was established, to monitor some population parameters of the penguin colonies, following the standard methods of the CCAMLR Ecosystem Monitoring Program. Three parameters were measured in the 2019-2020 and 2020-2021 seasons: breeding population size, breeding success and chick weight at fledging. For these parameters only Adelie and Gentoo penguins were considered due to the low number of Chinstrap pairs on the island. The breeding population size was measured applying the A3A method. Unfortunately, this parameter could only be measured in the first season, because in the 2020-2021 season logistical difficulties prevented arrival on time to record the beginning of laying. The breeding success was measured in Gentoo and Adelie penguins, using the A6C method. Finally, the weight of the chicks at fledging was measured applying method A7A. In the 2019-2020 season this parameter was only measured in Gentoo while in 2020-2021 it was possible to measure it also for Adelie. Overall, this pilot study settled the basis for a long-term monitoring of ecosystem changes using standard CCAMLR methods, in an area that has become a hub for touristic and logistic activities in the South Shetland Islands, and where research stations from several countries accumulate. The information generated by a long-term monitoring scheme will be key for the design, monitoring and assessments of the effectiveness of conservation measures as the proposed MPA. Remarkably, this pilot project allowed recording breeding parameters during the unusual conditions resulting from the logistic restrictions imposed by the COVID-19 pandemic. Thus, providing valuable data on colonies performance when human activities in the area are limited to a minimum.

The Ross Sea, Antarctica, is amongst the least human-impacted marine environments, and the site of the world’s largest Marine Protected Area, the Ross Sea region Marine Protected Area. We present research on two components of the Ross Sea benthic fauna: mega-epifauna, and macro-infauna, sampled using video and multicore, respectively, on the continental shelf and in previously unsampled habitats on the northern continental slope and abyssal plain. We describe physical habitat characteristics and community composition, in terms of faunal diversity, abundance, and functional traits, and compare similarities within and between habitats. We also examine relationships between faunal distributions and ice cover and productivity, using summaries of satellite-derived data over the decade prior to our sampling. Clear differences in seafloor characteristics and communities were noted between environments. Seafloor substrates were more diverse on the Slope and Abyss, while taxa were generally more diverse on the Shelf. Mega-epifauna were predominantly suspension feeders across the Shelf and Slope, with deposit feeder-grazers found in higher or equal abundances in the Abyss. In contrast, suspension feeders were the least common macro-infaunal feeding type on the Shelf and Slope. Concordance between the mega-epifauna and macro-infauna data suggests that non-destructive video sampling of mega-epifauna can be used to indicate likely composition of macro-infauna, at larger spatial scales, at least. Primary productivity, seabed organic flux, and sea ice concentrations, and their variability over time, were important structuring factors for both community types. This illustrates the importance of better understanding bentho-pelagic coupling and incorporating this in biogeographic and process-distribution models, to enable meaningful predictions of how these ecosystems may be impacted by projected environmental changes. This study has enhanced our understanding of the distributions and functions of seabed habitats and fauna inside and outside the Ross Sea MPA boundaries, expanding the baseline dataset against which the success of the MPA, as well as variability and change in benthic communities can be evaluated longer term.

We provide a summary of the New Zealand research voyage to the Ross Sea region in 2021. The Ross Sea Life in a Changing Climate (ReLiCC) 2021 voyage on RV Tangaroa, TAN2101, was the first of two research voyages to the Ross Sea region funded by the New Zealand Ministry of Business, Innovation, and Employment (MBIE) for the 2021 and 2023 austral summer seasons. The over-arching purpose of this multi-disciplinary research voyage was to increase knowledge about key environmental and biological processes in the Ross Sea region of Antarctica and the Southern Ocean, and thereby improve understanding of ecosystem function and likely responses to future change. The focus was on providing baseline information about the Ross Sea region Marine Protected Area (MPA) to allow scientific evaluation of its effectiveness. There were nine voyage objectives: 1) microbial plankton communities; 2) biogeochemistry; 3) coastal marine processes; 4) oceanography; 5) underway mapping; 6) mesopelagic fish; 7) zooplankton; 8) cetaceans; and 9) Southern Ocean safety systems evaluation. Weather and sea conditions were generally favourable during the voyage, and most of the work planned across the nine research objectives was completed. In addition to the nine core research proposals, the voyage also deployed surface-drifting weather buoys as part of the international Global Drifter Program, and several wave-monitoring drifters.

Sea ice algae in the Southern Ocean have strong ecological and biogeochemical significance, providing a lipid rich food-resource to keystone species such as Antarctic krill. Despite their ecological importance, estimating seasonal or interannual changes in ice algal production at the Antarctic circumpolar scale is not presently possible. We show that the product of ice concentration and irradiance penetrating into sea ice (E_ice) explains 69% of the variability in ice algal production at the sector and seasonal scale estimated from two respected sea ice algae models. After allowing for a greater quantum yield of sea ice algae in summer than in other seasons we estimated a simple light-based index of potential ice algal production (P_ice) and this explained 91% of the variability in modelled ice algal production. Our results suggest that between 1987 and 2017, ice algal production has generally increased with the largest increases seen off East Antarctica, the Weddell Sea, and the western Ross Sea.

Within the framework of the Marine Ecosystem Assessment for the Southern Ocean (MEASO), Pinkerton et al. (2021) brings together analyses of recent trends in phytoplankton biomass, primary production and irradiance at the base of the mixed layer in the Southern Ocean and summarises future projections. Satellite observations suggest that phytoplankton biomass in the mixed-layer has increased over the last 20 years in most (but not all) parts of the Southern Ocean, whereas primary production at the base of the mixed-layer has likely decreased over the same period. Different satellite models of primary production (Vertically Generalised versus Carbon Based Production Models) give different patterns and directions of recent change in net primary production (NPP) as they index different components of productivity. At present, the satellite record is not long enough to distinguish between trends and climate-related cycles in primary production. Over the next 100 years, Earth system models project increasing NPP in the water column in the MEASO northern and Antarctic zones but decreases in the Subantarctic zone. Low confidence in these projections arises from: (1) the difficulty in mapping supply mechanisms for key nutrients (silicate, iron); and (2) understanding the effects of multiple stressors (including irradiance, nutrients, temperature, pCO2, pH, grazing) on different species of Antarctic phytoplankton. Notwithstanding these uncertainties, there are likely to be changes to the seasonal patterns of production and the microbial community present over the next 50–100 years and these changes will have ecological consequences across Southern Ocean food-webs, especially on key species such as Antarctic krill and silverfish.

In 2016 the Commission adopted Conservation Measure (CM) 91-05, establishing the Ross Sea region Marine Protected Area. This paper updates the research and monitoring activities conducted by New Zealand relevant to the Ross Sea region Marine Protected Area, as encouraged by CM 91-05 paragraph 16(i)–(ii). Annex B of this Conservation Measure specifies the RSrMPA specific objectives and the Management Plan. In addition, Annex C specifies the Priority Elements for Scientific Research and Monitoring, including research and monitoring priorities and research and monitoring questions that should be addressed. We also recall the objectives of the RSrMPA and the research questions for research and monitoring for the RSrMPA. In 2016 the Commission adopted Conservation Measure (CM) 91-05, establishing the Ross Sea region Marine Protected Area. This paper updates the research and monitoring activities conducted by New Zealand relevant to the Ross Sea region Marine Protected Area, as encouraged by CM 91-05 paragraph 16(i)–(ii). Annex B of this Conservation Measure specifies the RSrMPA specific objectives and the Management Plan. In addition, Annex C specifies the Priority Elements for Scientific Research and Monitoring, including research and monitoring priorities and research and monitoring questions that should be addressed. We also recall the objectives of the RSrMPA and the research questions for research and monitoring for the RSrMPA.