Article
Ecology
Jenny Hieronymus, Kari Eilola, Malin Olofsson, Inga Hense, H. E. Markus Meier, Elin Almroth-Rosell
Summary: By introducing a cyanobacteria life cycle model, researchers have successfully improved the representation of cyanobacteria in the Baltic Sea within a three-dimensional coupled model, enhancing their ability to predict seasonal patterns. This model can be utilized to continuously predict internal nitrogen loads in Baltic Sea ecosystem management.
Article
Environmental Sciences
Oscar Dario Beltran-Perez, Joanna J. Waniek
Summary: The study investigated the inter-annual variability and phenology of spring and summer phytoplankton blooms in the eastern Baltic Sea. Results showed that summer blooms occur earlier, last longer, and are more sensitive to changes in environmental conditions compared to spring blooms.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Marine & Freshwater Biology
Ellen R. Salamon Slater, Kendra A. Turk-Kubo, Soren Hallstrom, Katharina Kesy, Peeter Laas, Jonathan Magasin, Jonathan P. Zehr, Matthias Labrenz, Lasse Riemann
Summary: Nitrogen fixation rates in the Baltic Sea are high, but knowledge about the composition and distribution of diazotrophs is limited. This study reveals that Pseudanabaena and non-cyanobacterial diazotrophs dominate the composition, while filamentous heterocyst-forming cyanobacteria account for most of the nitrogenase gene expression. Salinity has some influence on the composition, and different diazotrophs show varying expression levels at different salinities.
ESTUARINE COASTAL AND SHELF SCIENCE
(2023)
Article
Geosciences, Multidisciplinary
T. Klintzsch, H. Geisinger, A. Wieland, G. Langer, G. Nehrke, M. Bizic, M. Greule, K. Lenhart, C. Borsch, M. Schroll, F. Keppler
Summary: Aquatic ecosystems have a significant impact on global methane cycling, with studies showing methane supersaturation in the oxic surface mixed layer (SML) of oceans and epilimnion of lakes. The origin of methane formed under oxygenated conditions is hotly debated, but stable isotope measurements suggest that methane from phytoplankton is distinguishable from methane produced by methanogenic archaea. Comparing laboratory experiments with field measurements, it is suggested that algal and cyanobacterial populations substantially contribute to methane formation in the SML of oceans and lakes.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Engineering, Environmental
Malin Olofsson, Isabell Klawonn, Bengt Karlson
Summary: It was found that dense blooms of diazotrophic filamentous cyanobacteria are formed every summer in the Baltic Sea, contributing significantly to nitrogen fixation. The estimated nitrogen fixation rates exceed external nitrogen loading in some regions, highlighting the importance of such estimates for ecosystem management.
Article
Chemistry, Multidisciplinary
Ian-Andreas Rahn, Kersti Kangro, Andres Jaanus, Krista Alikas
Summary: This study aimed to test and develop indicators for remote sensing assessment of cyanobacterial blooms and their impact on eutrophication and environmental status. Various methods and data were used to evaluate and monitor cyanobacterial blooms in the Estonian coastal regions.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Environmental
Sylvain Bouchet, Anne L. Soerensen, Erik Bjorn, Emmanuel Tessier, David Amouroux
Summary: Identifying Hg sources and controlling Hg levels in aquatic ecosystems is crucial. This study investigated the Hg concentrations and stable isotopes in sediment, seston, and fish from different basins in the Baltic Sea. The results showed that terrestrial and industrial sources contribute to Hg in sediments, while atmospheric inputs affect odd Hg isotopes. Additionally, wet-deposited Hg accumulates more in northern basins, and the extent of MMHg photodegradation varies across different regions.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Microbiology
Ineta Liepina-Leimane, Ieva Barda, Iveta Jurgensone, Atis Labucis, Natalija Suhareva, Vendija Kozlova, Agita Maderniece, Juris Aigars
Summary: This study used the (15)N tracer method to investigate the diazotrophic activity in different seasons in the Gulf of Riga, Baltic Sea. The results show that Aphanizomenon flosaquae, the dominant cyanobacteria species in the region, has a strong correlation between its heterocyst biomass and N-2 fixation rate. This study highlights the importance of a heterocyst-focused approach in accurately evaluating diazotrophic activity.
FEMS MICROBIOLOGY ECOLOGY
(2022)
Review
Oceanography
Toru Kobari, Maharu Shinyashiki, Kanako Saito, Gen Kume, Mutsuo Ichinomiya, Tomohiro Komorita, Hiroomi Miyamoto, Yuji Okazaki, Fumihiro Makino, Ryuji Fukuda, Fujio Hyodo, Maki Noguchi-Aita
Summary: This study investigated the trophic sources and pathways of mesozooplankton and fish larvae in the East China Sea. The results showed that the main trophic sources for these organisms were copepods and appendicularians, and their dependence on diazotrophic production was greater in pelagic waters.
PROGRESS IN OCEANOGRAPHY
(2023)
Article
Environmental Sciences
Kaisa Kraft, Jukka Seppala, Heidi Hallfors, Sanna Suikkanen, Pasi Ylostalo, Silvia Angles, Sami Kielosto, Harri Kuosa, Lauri Laakso, Martti Honkanen, Sirpa Lehtinen, Johanna Oja, Timo Tamminen
Summary: This study presented the first results of using IFCB on a Baltic Sea cyanobacterial bloom community, demonstrating the pros and cons in identifying filamentous cyanobacterial taxa and estimating their biomass. The results compared well with light microscopical analysis, especially for Dolichospermum, while slight variations were observed for Aphanizomenon biomass. The study highlighted the relationship between community shifts and water movement in understanding the development of cyanobacteria summer blooms.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Environmental Sciences
Igor Fernandez-Urruzola, Antonio Bode, Natalie Loick-Wilde, Wolfgang Schneider, Dhugal Lindsay, Ruben Escribano
Summary: This comprehensive field study explores depth-resolved changes in the trophic strategies of different size-classes of mesozooplankton from distinct habitats across the Southeast Pacific. The research finds that shifts in productivity and nitrogen sources have limited impact on the trophic position of mesozooplankton, but microbial contributions to mid-trophic level consumers are more significant at higher productivities.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Environmental Sciences
Antonio Bode, Victoria Besada, Begona Perez-Fernandez, Lucia Vinas
Summary: This study identified differences in trophic resource exploitation between geographically adjacent Yellow-legged Gull nesting colonies through the analysis of stable nitrogen isotopes in their eggs. Despite similar trophic positions, gulls in the Cies Islands obtained a substantial portion of lysine from garbage dump sites, while those from the urban colony relied on fish discards. This finding highlights the importance of detailed diet estimations in assessing the conservation status and pollution risks of marine ecosystems.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Oceanography
Sarah C. Weber, Natalie Loick-Wilde, Joseph P. Montoya, Melvin Bach, Hai Doan-Nhu, Ajit Subramaniam, Iris Liskow, Lam Nguyen-Ngoc, Dirk Wodarg, Maren Voss
Summary: The study revealed a shift in the nitrogen source for biological production in mesozooplankton across four different habitats, indicating a change from nitrate in near-coastal waters to diazotroph-N inputs in oceanic waters. This shift was accompanied by an increase in trophic position, suggesting a connection between diazotrophy and the efficiency of nitrogen transfer through the marine food web. The high trophic enrichment value of 5.1 parts per thousand suggested a link between ecosystem heterogeneity and the less efficient transfer of mass and energy across trophic levels.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2021)
Article
Geochemistry & Geophysics
Florian Kurzweil, Olaf Dellwig, Martin Wille, Ronny Schoenberg, Helge W. Arz, Carsten Muenker
Summary: Manganese oxides preferentially adsorb light tungsten isotopes in marine environments, leading to heavier W isotope compositions in seawater. The stable W isotope data in sediments are related to the oxygenation level of seawater, indicating its potential as a tracer for early Earth redox reconstructions.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Engineering, Environmental
Riikka K. Vainio, Veijo Jormalainen, Rune Dietz, Toni Laaksonen, Ralf Schulz, Christian Sonne, Jens Sondergaard, Jochen P. Zubrod, Igor Eulaers
Summary: This study investigated the trophic dynamics of Hg in the polluted Baltic Archipelago Sea using trophic magnification and biomagnification factors. The results showed overall biomagnification of THg, with higher TMFs in pelagic species compared to benthic species when excluding homeotherm birds. However, when including homeotherm birds, the difference in TMFs between benthic and pelagic species disappeared. The study emphasizes the importance of considering ecological and ecophysiological traits when studying trophic contaminant dynamics.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Ecology
Elvita Eglite, Martin Graeve, Joerg Dutz, Dirk Wodarg, Iris Liskow, Detlef Schulz-Bull, Natalie Loick-Wilde
ECOLOGY AND EVOLUTION
(2019)
Article
Microbiology
William D. Orsi, Aurele Vuillemin, Paula Rodriguez, Oemer K. Coskun, Gonzalo Gomez-Saez, Gaute Lavik, Volker Morholz, Timothy G. Ferdelman
NATURE MICROBIOLOGY
(2020)
Correction
Microbiology
William D. Orsi, Aurele Vuillemin, Paula Rodriguez, Omer K. Coskun, Gonzalo V. Gomez-Saez, Gaute Lavik, Volker Mohrholz, Timothy G. Ferdelman
NATURE MICROBIOLOGY
(2020)
Article
Geosciences, Multidisciplinary
Christian Katlein, Volker Mohrholz, Igor Sheikin, Polona Itkin, Dmitry Divine, Julienne Stroeve, Arttu Jutila, Daniela Krampe, Egor Shimanchuk, Ian Raphael, Benjamin Rabe, Ivan Kuznetov, Maria Mallet, Hailong Liu, Mario Hoppmann, Adela Dumitrascu, Stefanie Arndt, Philipp Anhaus, Marcel Nicolaus, Ilkka Matero, Marc Oggier, Hajo Eicken, Christian Haas
GEOPHYSICAL RESEARCH LETTERS
(2020)
Article
Oceanography
Kirstin Schulz, Markus Janout, Yueng-Djern Lenn, Eugenio Ruiz-Castillo, Igor Polyakov, Volker Mohrholz, Sandra Tippenhauer, Krissy Anne Reeve, Jens Hoelemann, Benjamin Rabe, Myriel Vredenborg
Summary: This study quantifies oceanic heat fluxes along the continental slope of the Eurasian part of the Arctic Ocean, focusing on the fate of warm Atlantic Water and the observed heat loss of the Arctic Boundary Current (ABC). The results show that mixing with colder water along the continental margins is a significant contribution to AW heat loss, and the importance of both surface warming and increased vertical mixing in a future ice-free Arctic Ocean in summer is highlighted.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2021)
Article
Physiology
Jorge Toro-Chacon, Flora Tickell, Rodrigo Gonzalez, Pedro F. Victoriano, Igor Fernandez-Urruzola, Mauricio A. Urbina
Summary: The study evaluated both aerobic and anaerobic metabolic scaling in the endemic Chilean freshwater crayfish Parastacus pugnax, finding that anaerobic metabolism does not scale with crayfish size, suggesting adaptation to hypoxic environments throughout their ontogeny.
JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMS AND ENVIRONMENTAL PHYSIOLOGY
(2021)
Article
Limnology
Igor Fernandez-Urruzola, Osvaldo Ulloa, Ronnie N. Glud, Matthew H. Pinkerton, Wolfgang Schneider, Frank Wenzhofer, Ruben Escribano
Summary: Respiration plays a critical role in the cycling of particulate matter and regulates the carbon export to the deep ocean. Plankton < 100 mu m contributes significantly to total community respiration, with remineralization rates being highest in the euphotic zone. The study suggests that large fast-sinking particles from the surface ocean effectively sustain the respiratory carbon demands in ultra-deep marine environments.
LIMNOLOGY AND OCEANOGRAPHY
(2021)
Article
Ecology
William D. Orsi, Aurele Vuillemin, Omer K. Coskun, Paula Rodriguez, Yanik Oertel, Jutta Niggemann, Volker Mohrholz, Gonzalo Gomez-Saez
Summary: This study investigated the role of fungi in the marine carbon cycle using C-13 DNA stable isotope probing and phylogenetic analysis. The findings showed that saprotrophic fungi related to the yeast Malassezia were the main fungal foragers of pelagic dEPS, while fungi in sulfidic sediments assimilated more carbon from chemosynthetic bacteria. The research reveals the functional relevance of fungal diversity in structuring carbon flow in marine ecosystems.
Article
Environmental Sciences
Natalia Osma, Cristian A. Vargas, Maria Alguero-Muniz, Lennart T. Bach, May Gomez, Henriette G. Horn, Andrea Ludwig, Theodore T. Packard, Ulf Riebesell, Vanesa Romero-Kutzner, Jan Taucher, Igor Fernandez-Urruzola
Summary: The study revealed that ocean acidification can reduce the metabolic and enzymatic rates of zooplankton, particularly affecting the mesozooplankton community. Nutrient-rich conditions can promote diatom blooms and affect the metabolic performance of zooplankton significantly.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Multidisciplinary Sciences
Kirstin Schulz, Volker Mohrholz, Ilker Fer, Markus Janout, Mario Hoppmann, Janin Schaffer, Zoe Koenig
Summary: This study obtained unprecedented data on turbulent mixing in the Arctic Ocean, providing valuable information on the vertical profiles of turbulent dissipation rate and water column properties. The data set allows for a systematic assessment of upper ocean mixing and can help improve turbulence parameterizations in ocean circulation models.
Review
Engineering, Environmental
Elvita Eglite, Clarissa Mohm, Jan Dierking
Summary: Food web research is essential for understanding ecosystem functioning, but its practical application in ecosystem-based management is hindered by a lack of knowledge synthesis. In this study, the authors conducted a systematic review of ecological studies in the heavily impacted Baltic Sea macro-region using stable isotope analysis, identifying both advancements and limitations in the field. They propose enhanced collaboration and integration, including the submission of primary datasets to stable isotope databases, to overcome current shortcomings and promote future research and resource management.
Article
Limnology
Xinxin Li, Xin Zhao, Hongyue Dang, Chuanlun Zhang, Igor Fernandez-Urruzola, Zhiqiang Liu, Frank Wenzhoefer, Ronnie N. Glud
Summary: This study focuses on the study of Hadal sediments in the Atacama Trench in the Pacific Ocean. It found that Hadal sediments are important carbon deposition centers and have intensified microbial activity. The sources and turnover of hadopelagic organic carbon and its linkages to microbial activities have not been studied. The research also found that particulate organic carbon, dark carbon fixation, and size-fractionated microbial community respiration proxy attenuate rapidly with increasing depth in the water, but remain stable in bathypelagic and abyssopelagic waters. High variability in organic carbon sources and microbial activities was observed in the hadopelagic trench.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Geochemistry & Geophysics
Michael Kossack, Florian Scholz, Chloe H. Anderson, Paul Vosteen, Chih-Chieh Su, Volker Mohrholz, Matthias Zabel
Summary: In this study, the influence of spatially and seasonally contrasting redox conditions on the formation of authigenic Mo and U enrichments in organic carbon (TOC) rich mud belt sediments on the Namibian shelf was investigated. The results emphasize the importance of short-term redox fluctuations in the bottom waters and underlying sediments, as well as lateral sediment transport for the authigenic enrichment of redox-sensitive trace metals in reducing shelf sediments.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Environmental Sciences
Edgart Flores, Igor Fernandez-Urruzola, Sebastian I. Cantarero, Matias Pizarro-Koch, Matthias Zabel, Julio Sepulveda, Osvaldo Ulloa
Summary: This study provides new insights into the sources and distribution of organic matter (OM) in the Atacama Trench. The results indicate that the majority of OM in the trench comes from deep-sea sediments rather than the surface ocean. These findings are important for understanding carbon cycling and predicting climate change.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2023)