GEOMAR Helmholtz Centre for Ocean Research Kiel

A comprehensive phylogenomic framework for brachiopod evolution among lophotrochozoans

Brachiopods appeared early in the Cambrian radiation and represent an important clade for understanding the origin of animal body plans and the evolution of biomineralized structures. A robust phylogenetic framework of the living representatives is needed to answer persistent que...

Distinct drivers control trace metal distributions through the Atlantic Ocean

Trace metals (TMs) including iron, manganese, cobalt, nickel, copper, zinc, cadmium, and lead have important biogeochemical roles in the ocean. However, the controlling factors of TM distributions have not yet been quantified and investigated on an ocean scale. Here we take a hol...

Hidden subsurface suspended sediment export from Greenland's marine‐terminating glaciers

Abstract Runoff and calved ice volumes from the Greenland Ice Sheet are well constrained, but quantifying the associated suspended sediment flux remains challenging. Here we present near‐terminus observations from three glacierized fjords in southeast Greenland, combining full‐de...

Antarctic sea ice response to meltwater due to Antarctic ice sheet mass loss in a multi-model ensemble

Abstract. We present the first multi-model study of the Antarctic sea ice response to enhanced meltwater due to dynamic mass loss from the Antarctic ice sheet. This meltwater flux (and its future increase under global warming) is not included in the most recent state-of-the-art c...

Remobilized volcanogenic sediments boost photophysiological activity in three symbiotic reef-building coral species

Abstract Coral reefs that surround volcanic islands are continually influenced by run-off carrying remobilized volcanogenic sediments. Although unaltered volcanic ash is known to supply trace metals that enhance coral holobiont productivity, the impacts of long-term exposure to w...

Impacts of simulated coastal ocean alkalinity enhancement on the seasonal carbon cycle in European waters under a low- and a high-emission scenario

One potentially scalable method to remove CO 2 from the air is ocean alkalinity enhancement (OAE), which works to lower the ocean's CO 2 partial pressure ( p CO 2 ) and accelerate CO 2 sequestration and durable storage. This study explores how OAE might affect the seasonal carbon...

A global consistent database of plankton and detritus from in situ imaging by the Underwater Vision Profiler 5

Plankton and detritus are essential components of the Earth's oceans influencing biogeochemical cycles and carbon sequestration. Climate change impacts their composition and fluxes, and marine ecosystems as a whole. To improve our understanding of these changes, standardized obse...

Seasonal influence on post-fire debris flow likelihood after the 2020 Lake Fire

The increasing severity of wildfires in Western North America is widely hypothesized to lead to an increase in the likelihood of post-fire debris flows (PFDF), specifically those triggered by high-intensity rain. PFDF likelihoods are highest in the first year and tend to decrease...

Unsupervised ecosystem risk assessment in the Baltic Sea reveals bottom-oxygen depletion and fishing pressure as key threats in species-abundant hotspots

Abstract Marine ecosystems are increasingly shaped by the combined effects of multiple environmental and anthropogenic stressors, generating non-linear, spatially heterogeneous patterns of risks to ecosystem functioning. The Baltic Sea represents a paradigmatic system where geogr...

Volcanic stratigraphy offshore East Montserrat: Selective preservation and subaqueous remobilisation in marine records

Abstract In tectonically active regions, volcanic eruptions generate large volumes of material that are transported offshore through processes such as pyroclastic density currents, turbidity currents, and secondary sediment remobilisation. These deposits form key stratigraphic ma...

A global mitochondrial genomic atlas illuminates freshwater microeukaryote diversity

Abstract Environmental genomics has transformed our view of the microbial world, yet progress remains largely prokaryote-centric. Among microbial eukaryotes, inconsistent marker choice and limited species-level resolution blunt diversity estimates and hinder cross-study synthesis...

Spring phytoplankton bloom dynamics reveal thresholds of ocean alkalinity enhancement in the North Sea

Abstract Spring phytoplankton blooms drive primary production and food web dynamics in marine ecosystems. Ocean alkalinity enhancement, a proposed carbon dioxide removal strategy, alters seawater chemistry and could disrupt planktonic food webs, yet its ecological consequences re...

Assessing the effects of climate change and fishing management on demersal stocks in the western Mediterranean: Rethinking WestMed-MAP effort reductions in the Balearic Islands

Bottom trawl fishing effort in the Balearic Islands has decreased considerably in recent decades due to a progressive fleet reduction and the implementation, since 2020, of the effort regime under the multiannual plan for demersal fisheries in the western Mediterranean (WestMed-M...

Metabolic switching between inorganic and organic phosphorus sustains microbial activity in an ultraoligotrophic ocean

Abstract Phosphorus scarcity constrains microbial activity in parts of the oligotrophic ocean, yet the extent to which dissolved organic phosphorus (DOP) supports microbial P demand remains unresolved. Here, we quantified the concentrations, turnover times, and uptake kinetics of...

Enhanced carbon loss in the Southern Ocean under mitigation scenarios

The Southern Ocean (SO) plays a pivotal role in the global carbon cycle by absorbing anthropogenic carbon dioxide (CO 2 ). Yet, it remains uncertain whether this role will persist under future mitigation efforts. Using idealized emission-driven simulations with the Community Eart...

Nitrous oxide and methane concentrations and air-sea fluxes in undersampled areas of the Mediterranean basin

Abstract. Nitrous oxide (N2O) and methane (CH4) are potent greenhouse gases for which oceanic contributions remain uncertain, particularly in undersampled regions like the Southwest and Southeast margins of the Mediterranean Sea, where there is a major observational gap. This dat...

Trends in Heat Stress During Heat Waves Across Europe (1979–2023)

Abstract With heat waves becoming more frequent and intense under global warming, heat stress is a growing public health risk. We analyze heat stress trends (Simplified Wet Bulb Globe Temperature, sWBGT) during European heatwaves (1979–2023) using observations and reanalysis data...

Buoyancy and polarity driven accumulation of dissolved organic matter in the sea surface microlayer during a phytoplankton bloom

Abstract. The sea surface microlayer (SML) is only 1–1000 µm thick but resembles a biologically and geochemically very active boundary that modulates the exchange of energy and matter between the ocean and atmosphere. Globally, the SML accumulates up to 200 Tg C yr−1 of organic m...

Phagocytosis of microbial symbionts supports embryonic nutrition in the sponge Halichondria panicea

Abstract Animals associate with microbial symbionts that play crucial roles in their nutrition and development, yet their function during gametogenesis and embryogenesis remains poorly understood. Here, we investigate host–symbiont dynamics throughout the reproductive cycle of th...

Competing Effects of Elastic Heterogeneity and Viscous Flow on Interseismic Coupling at Cascadia

Abstract Interseismic coupling maps are important tools for estimating future earthquake hazard at subduction zones. Often interseismic coupling is estimated from surface velocities using a homogeneous elastic Earth model. However, inversions that incorporate viscoelastic mantle...