• Energy Research

AbstractThere is strong evidence of an increase in primary production (PP) in the Arctic Ocean (AO) over the last two decades. Further increases will depend on the interplay between decreasing light limitation for primary producers, as the sea ice extent and thickness decrease, and the availability of nutrients, which is controlled by, but not limited to, inputs from the Atlantic and the Pacific Oceans. While these inputs are the major nutrient sources to the AO, ocean vertical mixing is required to bring the nutrients into the photic zone. We analyze data collected in the Western Eurasian Basin (WEB) between 1980 and 2016 and characterize the nutrient climatology of the various water masses. We conclude that there were no significant trends in the concentrations of the two macronutrients that typically limit PP in the AO (nitrate and silicic acid, in the case of diatoms), except a decreasing trend for silicic acid in Polar Surface Water (PSW), which is consistent with the reported increase in PP in the AO. We suggest that the Whalers Bay polynya, located in the northwestern corner of Svalbard, may act as a mixing hotspot, creating patches of nutrient replenished PSW. These patches may then be advected to higher latitudes under the ice pack, later boosting PP upon release from light limitation or else, keeping a nutrient reservoir that may be used in a subsequent growth season. It is likely that this remaining nutrient reservoir will decrease as sea ice cover retreats and light limitation alleviates.

A rigorous synthesis of the sea-ice ecosystem and linked ecosystem services highlights that the sea-ice ecosystem supports all 4 ecosystem service categories, that sea-ice ecosystems meet the criteria for ecologically or biologically significant marine areas, that global emissions driving climate change are directly linked to the demise of sea-ice ecosystems and its ecosystem services, and that the sea-ice ecosystem deserves specific attention in the evaluation of marine protected area planning. The synthesis outlines (1) supporting services, provided in form of habitat, including feeding grounds and nurseries for microbes, meiofauna, fish, birds and mammals (particularly the key species Arctic cod, Boreogadus saida, and Antarctic krill, Euphausia superba, which are tightly linked to the sea-ice ecosystem and transfer carbon from sea-ice primary producers to higher trophic level fish, mammal species and humans); (2) provisioning services through harvesting and medicinal and genetic resources; (3) cultural services through Indigenous and local knowledge systems, cultural identity and spirituality, and via cultural activities, tourism and research; (4) (climate) regulating services through light regulation, the production of biogenic aerosols, halogen oxidation and the release or uptake of greenhouse gases, for example, carbon dioxide. The ongoing changes in the polar regions have strong impacts on sea-ice ecosystems and associated ecosystem services. While the response of sea-ice–associated primary production to environmental change is regionally variable, the effect on ice-associated mammals and birds is predominantly negative, subsequently impacting human harvesting and cultural services in both polar regions. Conservation can help protect some species and functions. However, the key mitigation measure that can slow the transition to a strictly seasonal ice cover in the Arctic Ocean, reduce the overall loss of sea-ice habitats from the ocean, and thus preserve the unique ecosystem services provided by sea ice and their contributions to human well-being is a reduction in carbon emissions.

L'océan Austral est d'une importance disproportionnée dans son effet sur le système terrestre, ayant un impact sur les systèmes climatiques, biogéochimiques et écologiques, ce qui rend les changements observés récemment dans ce système préoccupants à l'échelle mondiale. L'amélioration de la compréhension et des compétences prédictives nécessaires pour comprendre et projeter les états futurs de l'océan Austral nécessite des observations soutenues. Au cours de la dernière décennie, le Système d'observation de l'océan Austral (SOOS) a établi des réseaux pour améliorer la coordination régionale et les groupes communautaires de recherche afin de faire progresser le développement des capacités du système d'observation. Ces réseaux soutiennent la réalisation de la vision à 20 ans de SOOS, qui consiste à développer un système circumpolaire qui assure des séries chronologiques de variables clés et offre le plus grand impact des données à tous les utilisateurs finaux clés. Bien que l'océan Austral reste l'une des régions océaniques les moins observées, une coordination internationale accrue et des progrès dans les plates-formes autonomes ont permis de progresser vers la satisfaction du besoin d'observations durables de cette région. Depuis 2009, la communauté de l'océan Austral a déployé plus de 5700 plateformes d'observation au sud du 40°S. Des efforts multidisciplinaires à grande échelle, pluriannuels ou soutenus ont été soutenus et fournissent maintenant des observations de variables essentielles à des échelles spatiales et temporelles qui permettent d'évaluer les changements observés dans les systèmes de l'océan Austral. La couverture d'observation améliorée, cependant, est principalement pour l'océan ouvert, englobe l'été, se compose principalement de variables océanographiques physiques et couvre la surface jusqu'à 2000 m. Des lacunes importantes subsistent dans les observations de l'océan impacté par la glace, de la glace de mer, des profondeurs de plus de 2000 m, de l'interface air-glace, des variables biogéochimiques et biologiques, et pour les saisons autres que l'été. Pour combler durablement ces lacunes en matière de données, il faut des avancées parallèles dans les réseaux de coordination, la cyberinfrastructure et les outils de gestion des données, la technologie des plateformes d'observation et des capteurs, les technologies d'interrogation des plateformes et de transmission des données, les cadres de modélisation et les exigences d'échantillonnage des variables clés convenues au niveau international. Cet article présente une déclaration de la communauté sur les principaux progrès scientifiques et observationnels de la dernière décennie et, surtout, une évaluation des principales priorités pour la décennie à venir, en vue de réaliser la vision de SOOS et de fournir des données essentielles à tous les utilisateurs finaux. El Océano Austral es desproporcionadamente importante en su efecto sobre el sistema de la Tierra, impactando en los sistemas climáticos, biogeoquímicos y ecológicos, lo que hace que los cambios observados recientemente en este sistema sean motivo de preocupación mundial. La mayor comprensión y las mejoras en la habilidad predictiva necesarias para comprender y proyectar los estados futuros del Océano Austral requieren observar de forma sostenida. Durante la última década, el Sistema de Observación del Océano Austral (SOOS) ha establecido redes para mejorar la coordinación regional y los grupos comunitarios de investigación para avanzar en el desarrollo de las capacidades del sistema de observación. Estas redes respaldan la entrega de la visión de 20 años de SOOS, que es desarrollar un sistema circumpolar que garantice series temporales de variables clave y brinde el mayor impacto de los datos a todos los usuarios finales clave. Aunque el Océano Austral sigue siendo una de las regiones oceánicas menos observadas, la mejora de la coordinación internacional y los avances en las plataformas autónomas han dado lugar a avances para abordar la necesidad de observar de forma sostenida esta región. Desde 2009, la comunidad del Océano Austral ha desplegado más de 5700 plataformas de observación al sur de 40°S. Se han apoyado esfuerzos multidisciplinarios a gran escala, plurianuales o sostenidos, y ahora se están observando variables esenciales a escalas espaciales y temporales que permiten evaluar los cambios observados en los sistemas del Océano Austral. Sin embargo, la cobertura observacional mejorada es predominantemente para el océano abierto, abarca el verano, consiste principalmente en variables oceanográficas físicas y cubre la superficie hasta 2000 m. Siguen existiendo lagunas significativas en las observaciones del océano afectado por el hielo, el hielo marino, las profundidades de más de 2000 m, la interfaz aire-mar-hielo, las variables biogeoquímicas y biológicas, y para estaciones distintas del verano. Abordar estas brechas de datos de manera sostenida requiere avances paralelos en las redes de coordinación, la ciberinfraestructura y las herramientas de gestión de datos, la plataforma de observación y la tecnología de sensores, las tecnologías de interrogación y transmisión de datos de la plataforma, los marcos de modelado y los requisitos de muestreo acordados internacionalmente de variables clave. Este documento presenta una declaración de la comunidad sobre el principal progreso científico y observacional de la última década y, lo que es más importante, una evaluación de las prioridades clave para la próxima década, hacia el logro de la visión de SOOS y la entrega de datos esenciales a todos los usuarios finales. The Southern Ocean is disproportionately important in its effect on the Earth system, impacting climatic, biogeochemical and ecological systems, which makes recent observed changes to this system cause for global concern. The enhanced understanding and improvements in predictive skill needed for understanding and projecting future states of the Southern Ocean require sustained observations. Over the last decade, the Southern Ocean Observing System (SOOS) has established networks for enhancing regional coordination and research community groups to advance development of observing system capabilities. These networks support delivery of the SOOS 20-year vision, which is to develop a circumpolar system that ensures time series of key variables, and deliver the greatest impact from data to all key end-users. Although the Southern Ocean remains one of the least-observed ocean regions, enhanced international coordination and advances in autonomous platforms have resulted in progress towards addressing the need for sustained observations of this region. Since 2009, the Southern Ocean community has deployed over 5700 observational platforms south of 40°S. Large-scale, multi-year or sustained, multidisciplinary efforts have been supported and are now delivering observations of essential variables at space and time scales that enable assessment of changes being observed in Southern Ocean systems. The improved observational coverage, however, is predominantly for the open ocean, encompasses the summer, consists of primarily physical oceanographic variables and covers surface to 2000 m. Significant gaps remain in observations of the ice-impacted ocean, the sea ice, depths more than 2000 m, the air-sea-ice interface, biogeochemical and biological variables, and for seasons other than summer. Addressing these data gaps in a sustained way requires parallel advances in coordination networks, cyberinfrastructure and data management tools, observational platform and sensor technology, platform interrogation and data-transmission technologies, modeling frameworks, and internationally agreed sampling requirements of key variables. This paper presents a community statement on the major scientific and observational progress of the last decade, and importantly, an assessment of key priorities for the coming decade, towards achieving the SOOS vision and delivering essential data to all end users. المحيط الجنوبي مهم بشكل غير متناسب في تأثيره على نظام الأرض، مما يؤثر على النظم المناخية والكيميائية الحيوية والإيكولوجية، مما يجعل التغييرات التي لوحظت مؤخرًا في هذا النظام مصدر قلق عالمي. يتطلب الفهم المعزز والتحسينات في المهارات التنبؤية اللازمة لفهم وإسقاط الحالات المستقبلية للمحيط الجنوبي ملاحظات مستمرة. على مدى العقد الماضي، أنشأ نظام مراقبة المحيط الجنوبي (SOOS) شبكات لتعزيز التنسيق الإقليمي ومجموعات مجتمع البحث لتعزيز تطوير قدرات نظام المراقبة. تدعم هذه الشبكات تقديم رؤية SOOS لمدة 20 عامًا، وهي تطوير نظام قطبي يضمن سلسلة زمنية من المتغيرات الرئيسية، وتحقيق أكبر تأثير من البيانات لجميع المستخدمين النهائيين الرئيسيين. على الرغم من أن المحيط الجنوبي لا يزال أحد مناطق المحيطات الأقل رصدًا، إلا أن التنسيق الدولي المعزز والتقدم في المنصات المستقلة أدى إلى إحراز تقدم نحو تلبية الحاجة إلى عمليات مراقبة مستدامة لهذه المنطقة. منذ عام 2009، نشر مجتمع المحيط الجنوبي أكثر من 5700 منصة مراقبة جنوب 40درجةجنوباً. تم دعم الجهود متعددة التخصصات واسعة النطاق أو متعددة السنوات أو المستمرة، وهي تقدم الآن ملاحظات للمتغيرات الأساسية في نطاقات المكان والزمان التي تمكن من تقييم التغييرات التي يتم ملاحظتها في أنظمة المحيط الجنوبي. ومع ذلك، فإن التغطية الرصدية المحسنة هي في الغالب للمحيط المفتوح، وتشمل الصيف، وتتكون في المقام الأول من المتغيرات الأوقيانوغرافية الفيزيائية وتغطي السطح حتى 2000 متر. لا تزال هناك فجوات كبيرة في ملاحظات المحيط المتأثر بالجليد، والجليد البحري، والأعماق التي تزيد عن 2000 متر، والواجهة بين الهواء والبحر والجليد، والمتغيرات البيوكيميائية والبيولوجية، ولمواسم أخرى غير الصيف. تتطلب معالجة فجوات البيانات هذه بطريقة مستدامة تقدمًا موازيًا في شبكات التنسيق والبنية التحتية السيبرانية وأدوات إدارة البيانات ومنصة المراقبة وتكنولوجيا الاستشعار واستجواب المنصة وتقنيات نقل البيانات وأطر النمذجة ومتطلبات أخذ العينات المتفق عليها دوليًا للمتغيرات الرئيسية. تقدم هذه الورقة بيانًا مجتمعيًا حول التقدم العلمي والرصدي الرئيسي في العقد الماضي، والأهم من ذلك، تقييم الأولويات الرئيسية للعقد المقبل، نحو تحقيق رؤية SOOS وتقديم البيانات الأساسية لجميع المستخدمين النهائيين.

Conceived as a major new tool for climate studies, the Surface Water and Ocean Topography (SWOT) satellite mission will launch in late 2021 and will retrieve the dynamics of the oceans upper layer at an unprecedented resolution of a few kilometers. During the calibration and validation (CalVal) phase in 2022, the satellite will be in a 1- day-repeat fast sampling orbit with enhanced temporal resolution, sacrificing the spatial coverage. This is an ideal opportunity - unique for many years to come - to coordinate in situ experiments during the same period for a focused study of fine scale dynamics and their broader roles in the Earth system. Key questions to be addressed include the role of fine scales on the ocean energy budget, the connection between their surface and internal dynamics, their impact on plankton diversity, and their biophysical dynamics at the ice margin. AP acknowledges support from the Spanish Research Agency and the European Regional Development Fund (Award no. CTM2016-78607-P/PRE-SWOT). Part of the research for this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. JW and L. L. Fu acknowledge the support from SWOT mission. We thank the “Délégation Générale de l’Armement” which funded through the “Programme d’Etudes Amont Protevs II” the 2018 PROTEVSBIOSWOT campaign (PI Franck Dumas from the Service hydrographique et océanographique de la Marine) and makes a fruitful collaboration with the SWOT Science Team possible.

AbstractIntense regional warming was observed in the western Antarctic Peninsula (WAP) over the last 50 years. Here, we investigate the impact of climate change on primary production (PP) in this highly productive region. This study is based on temporal data series of ozone thickness (1972–2010), sea ice concentration (1978–2010), sea‐surface temperature (1990–2010), incident irradiance (1988–2010) and satellite‐derived chlorophyll a concentration (Chl‐a, 1997–2010) for the coastal WAP. In addition, we apply a photosynthesis/photoinhibition spectral model to satellite‐derived data (1997–2010) to compute PP and examine the separate impacts of environmental forcings. Since 1978, sea ice retreat has been occurring earlier in the season (in March in 1978 and in late October during the 2000s) while the ozone hole is present in early spring (i.e. August to November) since the early 1990s, increasing the intensity of ultraviolet‐B radiation (UVBR, 280–320 nm). The WAP waters have also warmed over 1990–2010. The modelled PP rates are in the lower range of previously reported PP rates in the WAP. The annual open water PP in the study area increased from 1997 to 2010 (from 0.73 to 1.03 Tg C yr−1) concomitantly with the increase in the production season length. The coincidence between the earlier sea ice retreat and the presence of the ozone hole increased the exposure to incoming radiation (UVBR, UVAR and PAR) and, thus, increased photoinhibition during austral spring (September to November) in the study area (from 0.014 to 0.025 Tg C yr−1). This increase in photoinhibition was minor compared to the overall increase in PP, however. Climate change hence had an overall positive impact on PP in the WAP waters.