Article
Oceanography
Zhouqian Chen, Chunhua Qiu, Dongxiao Wang, Hong Liang, Yuqi Tao
Summary: The atmospheric saddle-field and oceanic saddle-field have distinct flow characteristics and environmental conditions. The oceanic saddle-field undergoes changes after a typhoon, triggering a submesoscale frontogenesis process. This submesoscale process helps improve our understanding of submesoscale motions and may contribute to the improvement of physical-chemical-ecology coupled models.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2023)
Article
Oceanography
Daiki Ito, Toshio Suga, Shinya Kouketsu, Eitarou Oka, Yoshimi Kawai
Summary: The study conducted five high-resolution hydrographic sections at the periphery of an anticyclonic mesoscale eddy north of the Kuroshio Extension to explore the evolution of submesoscale structure associated with mesoscale eddies. The results showed that submesoscale filaments, composed of cold and fresh water originating from the subarctic region, contribute to rapid water mass transport and effective mixing, influenced by strain fields, convergence, geostrophic forcing, and vertical shear of horizontal velocity. These findings suggest the important role of submesoscale filaments in water mass transport and transformation around mesoscale eddies in the Kuroshio Extension region.
JOURNAL OF OCEANOGRAPHY
(2021)
Article
Oceanography
Yang Yang, James C. McWilliams, X. San Liang, Hong Zhang, Robert H. Weisberg, Yonggang Liu, Dimitris Menemenlis
Summary: The study reveals that the submesoscale energy cascades in the eastern Gulf of Mexico exhibit high spatial heterogeneity, with the strongest submesoscale signals found in the northern Gulf of Mexico. During winter, the primary sources for submesoscale KE are buoyancy conversion and forward KE cascades from mesoscale processes.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2021)
Article
Multidisciplinary Sciences
Zhiwei Zhang, Yuelin Liu, Bo Qiu, Yiyong Luo, Wenju Cai, Qingguo Yuan, Yinxing Liu, Hong Zhang, Hailong Liu, Mingfang Miao, Jinchao Zhang, Wei Zhao, Jiwei Tian
Summary: Based on two high-resolution simulations, the authors find that submesoscale eddies significantly boost poleward oceanic heat transport in Antarctic waters by strengthening transport capability of mesoscale eddies through inverse energy cascade.
NATURE COMMUNICATIONS
(2023)
Article
Environmental Sciences
Nauzet Hernandez-Hernandez, Yeray Santana-Falcon, Sheila Estrada-Allis, Javier Aristegui
Summary: This study highlights the importance of submesoscale features in impacting the distribution and variability of phytoplankton in the ocean. Observational evidence is lacking for the complexity of short-term phytoplankton distribution and variability, which has been mainly inferred from theoretical and modeling approaches. The results suggest that both temporal and spatial variability may equally contribute to the total variance of picoplankton community in the mixed layer, with time being the principal contributor to variance in the deep chlorophyll maximum (DCM).
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Oceanography
Alberto C. Naveira Garabato, Xiaolong Yu, Jorn Callies, Roy Barkan, Kurt L. Polzin, Eleanor E. Frajka-Williams, Christian E. Buckingham, Stephen M. Griffies
Summary: This study provides an observational assessment of the kinetic energy (KE) transfer between mesoscale and submesoscale motions and discovers the seasonal reversal of KE transfer. The findings partially support previous modeling investigations while also challenging them, indicating a need for further research in this field.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)
Article
Environmental Sciences
Eduard Khachatrian, Nikita Sandalyuk, Pigi Lozou
Summary: The automatic detection and analysis of ocean eddies in the marginal ice zone through remote sensing is challenging but crucial for scientific applications. In this study, we investigated the potential of using YOLOv5, a deep convolutional neural network architecture, to detect eddies in high-resolution synthetic aperture radar data. Our approach achieved accurate results with minimal training data, demonstrating the effectiveness and robustness of the chosen model in identifying different types of eddies. This work contributes to advancing oceanography research and lays the foundation for automated eddy detection using synthetic aperture radar imagery in the marginal ice zone.
Article
Oceanography
Jinchao Zhang, Zhiwei Zhang, Bo Qiu, Xincheng Zhang, Hideharu Sasaki, Wei Zhao, Jiwei Tian
Summary: This study investigates for the first time the seasonal modulation of submesoscale kinetic energy in the northeastern South China Sea using data from a single mooring. The submesoscale kinetic energy shows an asymmetric annual cycle modulated by mixed-layer depth and mesoscale strain rate, and the inverse KE cascade may play a crucial role in modulating mesoscale KE temporal variation in winter.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2021)
Article
Oceanography
Zhiwei Zhang, Xincheng Zhang, Bo Qiu, Wei Zhao, Chun Zhou, Xiaodong Huang, Jiwei Tian
Summary: Submesoscales with large vertical velocities, vertical heat flux, and strong ageostrophic KE were discovered in the northwestern Pacific subtropical countercurrent region during 2017-19. These submesoscales are most energetic during winter-spring season and generally weak in summer-autumn season. Energies analysis indicates that submesoscales receive KE from potential energy release but lose some of it through inverse cascade, suggesting a forward cascade balance mechanism.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2021)
Article
Oceanography
Dhruv Balwada, Qiyu Xiao, Shafer Smith, Ryan Abernathey, Alison R. Gray
Summary: This study demonstrates that criteria based on surface vorticity and strain JPDF can effectively decompose the surface velocity field into distinguishable flow regions, with different flow features contained in different regions. Conditioning vertical tracer transport on the vorticity-strain JPDF can help attribute the transport to different types of flows and scales.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2021)
Article
Environmental Sciences
Seyed Mahmood Hamze-Ziabari, Mehrshad Foroughan, Ulrich Lemmin, David Andrew Barry
Summary: Large-scale coherent circulations, such as gyres and eddies, are common in large lakes and play a crucial role in determining water quality. However, field measurements of near-surface currents in lakes are challenging due to their high variability. Satellite imagery, combined with numerical simulations and field observations, can provide valuable insights into the mesoscale and submesoscale processes in lakes. In this study, Sentinel-1 SAR satellite imagery was used to identify gyres/eddies in Lake Geneva, and the results were validated using numerical models and in situ observations.
Article
Geosciences, Multidisciplinary
S. M. Hamze-Ziabari, A. M. Razmi, U. Lemmin, D. A. Barry
Summary: Submesoscale filaments have been found in Lake Geneva for the first time based on high-resolution 3D numerical simulations, field observations, and remote sensing imagery. These filaments are formed during summertime and have significant impacts on the biophysical processes in the lake.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Limnology
Eduard Fadeev, Matthias Wietz, Wilken-Jon von Appen, Morten H. Iversen, Eva-Maria Noethig, Anja Engel, Julia Grosse, Martin Graeve, Antje Boetius
Summary: The study reveals the presence of submesoscale filament in summerly Arctic waters, which enhances mixing of Polar and Atlantic water masses and shapes distinct biogeochemical conditions and microbial communities within a few kilometers of the ocean. This suggests the importance of investigating the role of submesoscale features in polar waters for surface ocean biodiversity and biogeochemical processes, particularly in the face of sea ice fate in the warming Arctic Ocean.
LIMNOLOGY AND OCEANOGRAPHY
(2021)
Article
Geosciences, Multidisciplinary
A. A. Kubryakov, A. I. Mizyuk, S. V. Stanichny
Summary: This article investigates the evolution of the Sevastopol eddies using altimetry measurements and a high-resolution Nemo numerical model. The eddies can reside in the Black Sea for >3-6 months, impacting cross-shelf exchange and nutrient fluxes. The stationarity of the eddies is mainly due to the continental slope acting as a barrier, preventing cyclonic propagation.
JOURNAL OF MARINE SYSTEMS
(2024)
Article
Oceanography
D. Ito, T. Kodama, Y. Shimizu, T. Setou, K. Hidaka, D. Ambe, S. Sogawa
Summary: The study investigates the contribution of oceanic front and its strengthening to subsurface chlorophyll a (CHL) concentration near the Kuroshio. It is found that frontogenesis leads to the shoaling of the nitracline and an increase in subsurface CHL concentration. Additionally, the study demonstrates that the strengthening of fronts can be estimated using satellite-derived data to determine the distribution of CHL concentration.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Review
Geochemistry & Geophysics
Gerhard J. Herndl, Barbara Bayer, Federico Baltar, Thomas Reinthaler
Summary: The deep ocean waters below 200 m depth is the largest habitat in terms of volume, hosting around 70% of the prokaryotic biomass in the oceanic water column. These waters are characterized by low temperature, increasing hydrostatic pressure, and decreasing organic matter supply with depth. Recent advancements in microbial oceanography have provided a refined understanding of the ecology of prokaryotes in the dark ocean.
ANNUAL REVIEW OF MARINE SCIENCE
(2023)
Article
Limnology
Markel Gomez-Letona, Javier Aristegui, Nauzet Hernandez-Hernandez, Maria Perez-Lorenzo, Xose Anton Alvarez-Salgado, Eva Teira, Marta Sebastian
Summary: This study investigates the vertical connectivity between surface productivity regimes and deep ocean prokaryotic communities. The results show that higher prokaryotic abundances and viabilities, as well as smaller cell sizes, are observed below highly productive surface waters. However, leucine uptake rates in deep waters do not show a clear relationship with surface productivity.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Limnology
Daniele De Corte, Marta M. Varela, Angeles M. Louro, Sarah K. Bercovici, Joaquin Valencia-Vila, Eva Sintes, Federico Baltar, Tamara Rodriguez-Ramos, Meinhard Simon, Antonio Bode, Thorsten Dittmar, Jutta Niggemann
Summary: Zooplankton grazing on phytoplankton promotes the release of organic matter into the water column and is consumed by prokaryotes, contributing to its molecular diversification. In a experiment using zooplankton-derived dissolved organic matter (DOM) as substrate, the prokaryotic community demonstrated exponential growth and transformed the DOM over the incubation period. The results suggest that zooplankton-prokaryotic interactions play a significant role in the ocean's carbon cycle.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Multidisciplinary Sciences
Moira Decima, Michael R. Stukel, Scott D. Nodder, Andres Gutierrez-Rodriguez, Karen E. Selph, Adriana Lopes dos Santos, Karl Safi, Thomas B. Kelly, Fenella Deans, Sergio E. Morales, Federico Baltar, Mikel Latasa, Maxim Y. Gorbunov, Matt Pinkerton
Summary: Salp blooms in the Southern Ocean have significant impacts on microbial dynamics and the global biological carbon pump (BCP). Their grazing activities reduce primary production and increase particle export, resulting in higher BCP efficiency compared to non-salp locations.
NATURE COMMUNICATIONS
(2023)
Article
Fisheries
Clare I. M. Adams, Gert-Jan Jeunen, Hugh Cross, Helen R. Taylor, Antoine Bagnaro, Kim Currie, Chris Hepburn, Neil J. Gemmell, Lara Urban, Federico Baltar, Michael Stat, Michael Bunce, Michael Knapp
Summary: In response to climate change, efficient monitoring methods are needed for rapidly shifting biodiversity patterns in the oceans. Environmental DNA (eDNA) metabarcoding has emerged as a cost-effective solution. Using eDNA, we detected four community types across a transect in the Southern Hemisphere and found that diversity patterns were mainly driven by planktonic organisms. This technique lays the foundations for multi-trophic environmental monitoring efforts.
ICES JOURNAL OF MARINE SCIENCE
(2023)
Review
Ecology
Eva Breyer, Federico Baltar
Summary: Previous investigations on ocean ecology and biogeochemistry have focused mainly on bacteria, archaea, and protists, neglecting pelagic fungi (mycoplankton) which were thought to only exist in association with solid substrates on the seafloor. However, recent studies have shown that pelagic fungi are found ubiquitously throughout the water column in all ocean basins and play an active role in organic matter degradation and nutrient cycling. This review highlights the current knowledge on mycoplankton ecology, identifies knowledge gaps and challenges, and emphasizes the need to recognize pelagic fungi as significant contributors to oceanic organic matter cycling and ecology.
TRENDS IN ECOLOGY & EVOLUTION
(2023)
Article
Oceanography
M. D. Perez-Hernandez, A. Hernandez-Guerra, L. Cana-Cascallar, C. Arumi-Planas, V. Cainzos, A. J. Gonzalez-Santana, M. A. Gutierrez-Guerra, A. Martinez-Marrero, A. Mosquera Gimenez, C. Presas Navarro, D. Santana-Toscano, P. Velez-Belchi
Summary: For the first time, four dedicated hydrographic cruises were carried out in 2015 around the Canary Islands to determine the seasonality of the flows at the eastern boundary of the North Atlantic Subtropical Gyre. The results show that the Canary Current has a seasonal behavior, flowing on the easternmost position in winter and on the westernmost position in fall. At the Lanzarote Passage, the dominant flow is southward except in fall, where a northward transport is observed.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Microbiology
Federico Baltar, Clara Martinez-Perez, Chie Amano, Marion Vial, Semidan Robaina-Estevez, Thomas Reinthaler, Gerhard J. Herndl, Zihao Zhao, Ramiro Logares, Sergio E. Morales, Jose M. Gonzalez
Summary: Through studying the samples collected beneath the Ross Ice Shelf in Antarctica using single-cell genomics, community metagenomics, metatranscriptomics, and single-cell activity measurements, we identified a ubiquitous mixotrophic bacterial group (UBA868) that plays a dominant role in the expression of sulfur oxidation and dissolved inorganic carbon fixation genes, thus highlighting its global distribution and importance in the mesopelagic ocean.
NATURE MICROBIOLOGY
(2023)
Article
Microbiology
Pavla Debeljak, Federico Baltar
Summary: Fungi have played a significant role in shaping the biosphere since the origin of life on Earth. However, research on fungal communities has been mainly focused on soils, leaving the role and composition of fungi in aquatic environments largely unexplored. In this study, we used a dataset of 18S rRNA sequences from various ecosystems to conduct a global assessment of fungal diversity. Our findings reveal different patterns of fungal diversity and community composition in terrestrial, freshwater, and marine environments, with the highest diversity found in terrestrial ecosystems. Additionally, we identified the most abundant fungi in each ecosystem, highlighting the dominant presence of Ascomycota and Basidiomycota in most environments, except for freshwater rivers where Chytridiomycota were dominant. This study fills an important knowledge gap in understanding the Earth's mycobiome.
Article
Microbiology
Marilena Heitger, Federico Baltar
Summary: This study measured the respiration and biomass production of three marine fungi under different temperature and nutrient concentration conditions. The results showed that fungal respiration and production rates varied among species, temperature, and nutrient concentration. Higher temperatures enhanced fungal respiration and production, while lower temperatures improved fungal growth efficiencies. Nutrient concentration influenced fungal respiration, production, and growth efficiency, but the effects differed among species. This study provides valuable insights into the role of pelagic fungi in the marine carbon cycle as a source/sink of carbon during organic matter remineralization.
Article
Environmental Sciences
Sheila N. Estrada-Allis, Angel Rodriguez-Santana, Alberto C. Naveira-Garabato, Luis Garcia-Weil, Mireya Arcos-Pulido, Mikhail Emelianov
Summary: The filaments of the African Eastern Boundary Upwelling System (EBUS) play a crucial role in providing nutrients to the oligotrophic waters of the northeastern Atlantic. This study examines the turbulent mixing associated with nutrient uplift in the Cape Ghir upwelling filament using microstructure profiler measurements. The results show that an increase in vertical current shear, rather than symmetrical instabilities induced by down-front winds, is responsible for the enhanced turbulent kinetic energy dissipation rates observed in the filament.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Ecology
Kristian Spilling, Jonna Piiparinen, Eric P. Achterberg, Javier Aristegui, Lennart T. Bach, Maria T. Camarena-Gomez, Elisabeth von der Esch, Martin A. Fischer, Markel Gomez-Letona, Nauzet Hernandez-Hernandez, Judith Meyer, Ruth A. Schmitz, Ulf Riebesell
Summary: The Peruvian upwelling system is a productive ecosystem with a large oxygen minimum zone (OMZ). A mesocosm experiment was conducted off Callao, Peru, with the addition of OMZ water collected from two different sites simulating different upwelling scenarios. The study focused on the pelagic remineralization of organic matter through the activity of leucine aminopeptidase (LAP) and alkaline phosphatase activity (APA). The results showed high enzyme activity, suggesting that bacterial community-driven pelagic N remineralization supported the high standing stock of primary producers in the mesocosms after N depletion.
Article
Ecology
Jens Hartmann, Niels Suitner, Carl Lim, Julieta Schneider, Laura Marin-Samper, Javier Aristegui, Phil Renforth, Jan Taucher, Ulf Riebesell
Summary: Ocean alkalinity enhancement (OAE) is a carbon dioxide removal (CDR) approach with potential for countering ocean acidification. However, its real-world application requires safe and sustainable procedures for adding alkalinity to seawater. The stability of alkalinity when added to seawater is a concern, as it can lead to carbonate precipitation and reduce the efficiency of CO2 removal. Experiments show that using CO2-equilibrated alkaline solution poses the lowest risk of losing alkalinity, while the addition of reactive alkaline solids can cause net loss if added alkalinity exceeds certain levels. Precipitates formed can partially redissolve, suggesting that net loss of alkalinity may not be permanent.
Article
Mycology
Katherine Salazar-Alekseyeva, Gerhard J. Herndl, Federico Baltar
Summary: Marine fungi have been found to release cell-free enzymes, which are potential contributors to the oceanic enzymatic pool. Salinity changes may affect the enzymatic activities of marine fungi and their potential contribution to oceanic biogeochemical cycles.
FRONTIERS IN FUNGAL BIOLOGY
(2023)
