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| 2. |
- Mock, Thomas, et al.
(author)
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Multiomics in the central Arctic Ocean for benchmarking biodiversity change
- 2022
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In: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 20:10
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Journal article (peer-reviewed)abstract
- Multiomics approaches need to be applied in the central Arctic Ocean to benchmark biodiversity change and to identify novel species and their genes. As part of MOSAiC, EcoOmics will therefore be essential for conservation and sustainable bioprospecting in one of the least explored ecosystems on Earth.
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| 3. |
- Smith, Madison M., et al.
(author)
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Thin and transient meltwater layers and false bottoms in the Arctic sea ice pack—Recent insights on these historically overlooked features
- 2023
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In: Elementa: Science of the Anthropocene. - 2325-1026. ; 11:1
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Research review (peer-reviewed)abstract
- The rapid melt of snow and sea ice during the Arctic summer provides a significant source of low-salinity meltwater to the surface ocean on the local scale. The accumulation of this meltwater on, under, and around sea ice floes can result in relatively thin meltwater layers in the upper ocean. Due to the small-scale nature of these upper-ocean features, typically on the order of 1 m thick or less, they are rarely detected by standard methods, but are nevertheless pervasive and critically important in Arctic summer. Observations during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition in summer 2020 focused on the evolution of such layers and made significant advancements in understanding their role in the coupled Arctic system. Here we provide a review of thin meltwater layers in the Arctic, with emphasis on the new findings from MOSAiC. Both prior and recent observational datasets indicate an intermittent yet longlasting (weeks to months) meltwater layer in the upper ocean on the order of 0.1 m to 1.0 m in thickness, with a large spatial range. The presence of meltwater layers impacts the physical system by reducing bottom ice melt and allowing new ice formation via false bottom growth. Collectively, the meltwater layer and false bottoms reduce atmosphere-ocean exchanges of momentum, energy, and material.The impacts on the coupled Arctic system are far-reaching, including acting as a barrier for nutrient and gas exchange and impacting ecosystem diversity and productivity.
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| 4. |
- Beck, Ivo, et al.
(author)
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Characteristics and sources of fluorescent aerosols in the central Arctic Ocean
- 2024
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In: Elementa. - 2325-1026. ; 12:1
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Journal article (peer-reviewed)abstract
- The Arctic is sensitive to cloud radiative forcing. Due to the limited number of aerosols present throughout much of the year, cloud formation is susceptible to the presence of cloud condensation nuclei and ice nucleating particles (INPs). Primary biological aerosol particles (PBAP) contribute to INPs and can impact cloud phase, lifetime, and radiative properties. We present yearlong observations of hyperfluorescent aerosols (HFA), tracers for PBAP, conducted with a Wideband Integrated Bioaerosol Sensor, New Electronics Option during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition (October 2019–September 2020) in the central Arctic. We investigate the influence of potential anthropogenic and natural sources on the characteristics of the HFA and relate our measurements to INP observations during MOSAiC. Anthropogenic sources influenced HFA during the Arctic haze period. But surprisingly, we also found sporadic “bursts” of HFA with the characteristics of PBAP during this time, albeit with unclear origin. The characteristics of HFA between May and August 2020 and in October 2019 indicate a strong contribution of PBAP to HFA. Notably from May to August, PBAP coincided with the presence of INPs nucleating at elevated temperatures, that is, >−9°C, suggesting that HFA contributed to the “warm INP” concentration. The air mass residence time and area between May and August and in October were dominated by the open ocean and sea ice, pointing toward PBAP sources from within the Arctic Ocean. As the central Arctic changes drastically due to climate warming with expected implications on aerosol–cloud interactions, we recommend targeted observations of PBAP that reveal their nature (e.g., bacteria, diatoms, fungal spores) in the atmosphere and in relevant surface sources, such as the sea ice, snow on sea ice, melt ponds, leads, and open water, to gain further insights into the relevant source processes and how they might change in the future.
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| 5. |
- Rabe, Benjamin, et al.
(author)
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The MOSAiC Distributed Network: Observing the coupled Arctic system with multidisciplinary, coordinated platforms
- 2024
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In: Elementa. - 2325-1026. ; 12:1
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Journal article (peer-reviewed)abstract
- Central Arctic properties and processes are important to the regional and global coupled climate system. The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Distributed Network (DN) of autonomous ice-tethered systems aimed to bridge gaps in our understanding of temporal and spatial scales, in particular with respect to the resolution of Earth system models. By characterizing variability around local measurements made at a Central Observatory, the DN covers both the coupled system interactions involving the ocean-ice-atmosphere interfaces as well as three-dimensional processes in the ocean, sea ice, and atmosphere. The more than 200 autonomous instruments (“buoys”) were of varying complexity and set up at different sites mostly within 50 km of the Central Observatory. During an exemplary midwinter month, the DN observations captured the spatial variability of atmospheric processes on sub-monthly time scales, but less so for monthly means. They show significant variability in snow depth and ice thickness, and provide a temporally and spatially resolved characterization of ice motion and deformation, showing coherency at the DN scale but less at smaller spatial scales. Ocean data show the background gradient across the DN as well as spatially dependent time variability due to local mixed layer sub-mesoscale and mesoscale processes, influenced by a variable ice cover. The second case (May–June 2020) illustrates the utility of the DN during the absence of manually obtained data by providing continuity of physical and biological observations during this key transitional period. We show examples of synergies between the extensive MOSAiC remote sensing observations and numerical modeling, such as estimating the skill of ice drift forecasts and evaluating coupled system modeling. The MOSAiC DN has been proven to enable analysis of local to mesoscale processes in the coupled atmosphere-ice-ocean system and has the potential to improve model parameterizations of important, unresolved processes in the future.
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| 6. |
- Schulz, Kirstin, et al.
(author)
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The Eurasian Arctic Ocean along the MOSAiC drift in 2019-2020: An interdisciplinary perspective on physical properties and processes
- 2024
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In: ELEMENTA-SCIENCE OF THE ANTHROPOCENE. - 2325-1026. ; 12:1
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Journal article (peer-reviewed)abstract
- The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC, 2 019-2 02 0), a year-long drift with the Arctic sea ice, has provided the scientific community with an unprecedented, multidisciplinary dataset from the Eurasian Arctic Ocean, covering high atmosphere to deep ocean across all seasons. However, the heterogeneity of data and the superposition of spatial and temporal variability, intrinsic to a drift campaign, complicate the interpretation of observations. In this study, we have compiled a qualitycontrolled physical hydrographic dataset with best spatio-temporal coverage and derived core parameters, including the mixed layer depth, heat fluxes over key layers, and friction velocity. We provide a comprehensive and accessible overview of the ocean conditions encountered along the MOSAiC drift, discuss their interdisciplinary implications, and compare common ocean climatologies to these new data. Our results indicate that, for the most part, ocean variability was dominated by regional rather than seasonal signals, carrying potentially strong implications for ocean biogeochemistry, ecology, sea ice, and even atmospheric conditions. Near-surface ocean properties were strongly influenced by the relative position of sampling, within or outside the river-water influenced Transpolar Drift, and seasonal warming and meltwater input. Ventilation down to the Atlantic Water layer in the Nansen Basin allowed fora stronger connectivity between subsurface heat and the sea ice and surface ocean via elevated upward heat fluxes. The Yermak Plateau and Fram Strait regions were characterized by heterogeneous water mass distributions, energetic ocean currents, and stronger lateral gradients in surface water properties in frontal regions. Together with the presented results and core parameters, we offer context for interdisciplinary research, fostering an improved understanding of the complex, coupled Arctic System.
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| 7. |
- Beck, Lisa J., et al.
(author)
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Differing Mechanisms of New Particle Formation at Two Arctic Sites
- 2021
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In: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 48:4
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Journal article (peer-reviewed)abstract
- New particle formation in the Arctic atmosphere is an important source of aerosol particles. Understanding the processes of Arctic secondary aerosol formation is crucial due to their significant impact on cloud properties and therefore Arctic amplification. We observed the molecular formation of new particles from low-volatility vapors at two Arctic sites with differing surroundings. In Svalbard, sulfuric acid (SA) and methane sulfonic acid (MSA) contribute to the formation of secondary aerosol and to some extent to cloud condensation nuclei (CCN). This occurs via ion-induced nucleation of SA and NH3 and subsequent growth by mainly SA and MSA condensation during springtime and highly oxygenated organic molecules during summertime. By contrast, in an ice-covered region around Villum, we observed new particle formation driven by iodic acid but its concentration was insufficient to grow nucleated particles to CCN sizes. Our results provide new insight about sources and precursors of Arctic secondary aerosol particles.
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| 8. |
- Koch, Xianyu, et al.
(author)
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Variability of Dissolved Organic Matter Sources in the Upper Eurasian Arctic Ocean
- 2024
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In: Journal of Geophysical Research - Oceans. - 0148-0227 .- 2156-2202. ; 129:6, s. 1-19
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Journal article (peer-reviewed)abstract
- Chromophoric dissolved organic matter (CDOM) is a ubiquitous component in marine environments, and substantial changes in its sources and distribution, related to the carbon cycle in the Arctic Ocean, are expected due to Arctic warming. In this study, we present unique CDOM data in the Eurasian Arctic Ocean derived from the year‐round MOSAiC expedition. We used CDOM absorbance spectra and fluorescence excitation‐emission matrices in combination with parallel factor analysis to characterize differences in DOM sources and composition. Our results suggested that terrestrial DOM was less sensitive to seasonal changes but controlled by regionality in hydrography. Elevated dissolved organic carbon (DOC) levels in polar surface water were primarily derived from terrigenous sources as identified by CDOM absorption and fluorescence characteristics. In the Amundsen Basin and western Fram Strait surface waters, to which terrestrial DOM is primarily transported by the Transpolar Drift, we found, on average, a 188% larger meteoric water fraction and a 40% higher DOC concentration compared to the Atlantic water that dominated western Nansen Basin and Yermak Plateau. In the Amundsen Basin, the DOC concentration in summer of surface water was only 13% higher compared to winter season. Additionally, autochthonous DOM and chlorophyll‐a concentrations were relatively low in surface water and exhibited significant differences compared to those observed in summer, while there were significant differences between autochthonous DOM and chlorophyll‐a. We also observed that sea ice melt contributed to autochthonous DOM in summer, while storms in winter affected the vertical distribution of terrestrial and autochthonous DOM in the subsurface.
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