A5039101627- Marine and coastal ecosystems
- Microbial Community Ecology and Physiology
- Methane Hydrates and Related Phenomena
- Geochemistry and Elemental Analysis
- Atmospheric and Environmental Gas Dynamics
- Soil and Water Nutrient Dynamics
- Hydrocarbon exploration and reservoir analysis
- Aquatic Ecosystems and Phytoplankton Dynamics
- Marine Biology and Ecology Research
- Marine and environmental studies
- Groundwater and Isotope Geochemistry
- Paleontology and Stratigraphy of Fossils
- Radioactive element chemistry and processing
- Wastewater Treatment and Nitrogen Removal
- Radiomics and Machine Learning in Medical Imaging
- Phosphorus and nutrient management
- Mine drainage and remediation techniques
- Heavy metals in environment
- Aquatic Invertebrate Ecology and Behavior
- Particle physics theoretical and experimental studies
- Atomic and Subatomic Physics Research
- Genomics and Phylogenetic Studies
- Geology and Paleoclimatology Research
- Mercury impact and mitigation studies
- Drilling and Well Engineering
University of Helsinki
2021-2024
Stockholm University
2023-2024
Östersjöcentrum
2023-2024
Utrecht University
2018-2024
Coastal zones account for 75% of marine methane emissions, despite covering only 15% the ocean surface area. In these ecosystems, tight balance between production and oxidation in sediments prevents most from escaping into seawater. However, anthropogenic activities could disrupt this balance, leading to an increased escape coastal sediments. To quantify unravel potential mechanisms underlying disruption, we used a suite biogeochemical microbiological analyses investigate impact...
Oxygen depletion in coastal waters may lead to release of toxic sulfide from sediments. Cable bacteria can limit by promoting iron oxide formation Currently, it is unknown how widespread this phenomenon is. Here, we assess the abundance, activity, and biogeochemical impact cable at 12 Baltic Sea sites. were mostly absent sediments overlain anoxic sulfidic bottom waters, emphasizing their dependence on oxygen or nitrate as electron acceptors. At sites that temporarily reoxygenated, bacterial...
Abstract. Coastal systems can act as filters for anthropogenic nutrient input into marine environments. Here, we assess the processes controlling removal of phosphorus (P) and nitrogen (N) four sites in eutrophic Stockholm archipelago. Bottom water concentrations oxygen (O2) P are inversely correlated. This is attributed to seasonal release from iron-oxide-bound (Fe-oxide-bound) surface sediments degrading organic matter. The abundant presence sulfide pore its high upward flux towards...
Abstract Continental shelves are a major source of iron (Fe) and manganese (Mn) to marine waters. Here, we investigate controls on benthic release Fe Mn the impact water column in Baltic Sea. We find high situ rates dissolved at seasonally hypoxic sites (bottom oxygen between 0–63 μ mol L −1 ) receiving inputs organic matter. that is sensitive bottom concentrations. Benthic likely additionally controlled by Fe–sulfur redox chemistry surface sediment. For Mn, correlates positively with oxide...
Coastal waters worldwide suffer from increased eutrophication and seasonal bottom water hypoxia. Here, we assess the dynamics of iron (Fe), manganese (Mn), phosphorus (P) in sediments eutrophic, brackish Gulf Finland populated by cable bacteria. At sites where are oxic spring, surface enrichments Fe Mn oxides high abundances bacteria were observed upon sampling early summer. one site, P enriched a thin layer (~ 3 mm) just below sediment-water interface. X-ray absorption near edge structure...
Abstract Using a combination of sediment trap experiments, sedimentary biogeochemical analyses and mass balance calculations, we conducted comprehensive quantitative evaluation the in-lake phosphorus (P) cycles including in both water phases for Lake Hiidenvesi, dimictic eutrophic lake southern Finland. We explicitly demonstrated heterogeneity P between basins with distinct morphological features. Enhanced interactions waters sediments occur shallow non-stratified areas, as evidenced by...
Coastal areas are an important source of methane (CH4). However, the exact origins CH4 in surface waters coastal regions, which turn drive sea-air emissions, remain uncertain. To gain a comprehensive understanding current and future climate change feedbacks, it is crucial to identify these sources processes that regulate its formation oxidation. This study investigated dynamics by comparing water column data from six stations located brackish Tvärminne Archipelago, Baltic Sea. The sediment...
Coastal ecosystems play a significant role in the cycling of greenhouse gases (GHGs), yet they remain understudied compared to open oceans and terrestrial systems. Here, we present measurements carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O) concentrations from shallow coastal environments along Swedish Baltic Sea coast Auckland, New Zealand, highlighting variability drivers GHG dynamics across diverse habitats.In Sea, conducted April September 2024,...
Abstract. Since the discovery of cable bacteria more than a decade ago, these multi-cellular, filamentous sulfur-oxidizing have been found in range sedimentary environments. However, their abundance, diversity and activity continental margin sediments overlain by oxygen-deficient waters at water depths >100 m remain poorly known. Here we address this studying five basins along coasts California Mexico. All are organic carbon rich (2.5 – 7.5 wt%) characterized active iron sulfur cycling....
Internal phosphorus (P) loading is widely recognized as a major cause of lake eutrophication. One conventional paradigm states that the magnitude internal through P diffusion constrained by presence iron (Fe) oxides in surface sediments under oxic conditions near sediment-water interface (SWI). However, biogeochemical dynamics Fe-rich sedimentary systems are still not fully understood, especially eutrophic lakes where intensively coupled organic matter (OM) remineralization and reductive...
Abstract. Cable bacteria can strongly alter sediment biogeochemistry. Here, we used laboratory incubations to determine the potential impact of their activity on cycling iron (Fe), phosphorus (P) and sulfur (S). Microsensor depth profiles oxygen, sulfide pH in combination with electric profiling fluorescence situ hybridisation (FISH) analyses showed a rapid development (<5 d) cable bacteria, followed by long period (>200 d). During most experiment, current density correlated linearly...
Abstract Coastal zones account for significant global marine methane emissions to the atmosphere. In coastal ecosystems, tight balance between microbial production and oxidation in sediments prevents most from escaping water column. Anthropogenic activities, causing eutrophication bottom deoxygenation, could disrupt this cycle lead increased release sediments. Here, we combined microbiological biogeochemical analyses of three sites along a redox gradient (oxic-hypoxic-euxinic) eutrophic...
Abstract. Sedimentary molybdenum (Mo) and uranium (U) enrichments are often used as redox proxies to reconstruct bottom water changes. However, these may not be equally reliable across a range of coastal settings due varying depositional environments. Fjords vary greatly in their conditions, unique bathymetry hydrography, highly vulnerable anthropogenic climatic pressures. Currently, it is unknown what extent Mo U sequestration affected by variable conditions fjords. Here, we use pore...
Abstract Recycling of phosphorus (P) from deoxygenated sediments perpetuates eutrophic conditions in parts the Baltic Sea. Sedimentary organic P is a major source dissolved to water column, but also sink for permanent burial. The mechanisms behind these two pathways are, however, largely unknown. Using new methods, we determined DNA and phospholipids, which are both found all organisms. We identified inositol phosphates that particularly important eukaryotes. Sediment cores were collected...
Hypoxia has occurred intermittently in the Baltic Sea since establishment of brackish-water conditions at ∼8,000 years B.P., principally as recurrent hypoxic events during Holocene Thermal Maximum (HTM) and Medieval Climate Anomaly (MCA). Sedimentary phosphorus release been implicated a key driver these events, but previous paleoenvironmental reconstructions have lacked sampling resolution to investigate feedbacks past iron-phosphorus cycling on short timescales. Here we employ Laser...
Abstract. Sedimentary molybdenum (Mo) and uranium (U) enrichments are often used as redox proxies to reconstruct bottom water changes. However, these may not be equally reliable across a range of coastal settings due varying depositional environments. Fjords vary greatly in their conditions, unique bathymetry hydrography, highly vulnerable anthropogenic climatic pressures. Currently, it is unknown what extent Mo U sequestration affected by variable conditions fjords. Here, we use pore...
Figure S1: Sub-basin division of the Baltic Sea in BALTSEM: 1. Northern Kattegat (NK), 2. Central (CK), 3. Southern (SK), 4. Samsø Belt (SB), 5. Fehmarn (FB), 6. Öresund (OS), 7. Arkona Basin (AR), 8. Bornholm (BN), 9. Gotland (GS
Abstract. Methane (CH4) cycling in the Baltic Sea is studied through model simulations that incorporate stable isotopes of CH4 (12C-CH4 and 13C-CH4) a physical-biogeochemical model. A preliminary budget identifies benthic release as dominant source, which largely balanced by oxidation water column to smaller degree outgassing. The contributions from land loads net export North are marginal importance. Simulated total emissions correspond an average 0.04 g m−2 y−1, can be compared calibrated...