Preprints
Filtering by Subject: Marine Biology
Random-split validation overstates the skill of machine-learning models of global coral bleaching severity
Published: 2026-10-21
Subjects: Climate, Environmental Indicators and Impact Assessment, Marine Biology, Oceanography, Statistical Methodology
Global compilations of coral bleaching surveys are increasingly used to train machine-learning models of bleaching severity, but such models are often evaluated with random train–test splits that ignore duplicated records, spatial dependence and differences among contributing survey programmes. We re-examined an earlier analysis of the Global Coral Bleaching Database (BCO-DMO dataset 773466) that [...]
Ecosystem community structure shapes carbon dynamics in the ocean
Published: 2026-10-19
Subjects: Climate, Marine Biology, Oceanography, Physical Sciences and Mathematics
Understanding how marine ecosystems influence air–sea CO2 flux under climate change remains a major uncertainty in ocean carbon-cycle projections. Progress is hampered by insufficient representation of ecosystem complexity in climate models and insufficient observations for developing and calibrating complex marine ecosystem models. We present a novel three-branch ensemble of the PlankTOM12 [...]
Wave-Driven Sliding, Ratcheting, and Overturning of Coral Transplant Units: An Idealized Nonsmooth Contact Model
Published: 2026-10-11
Subjects: Environmental Monitoring, Marine Biology, Numerical Analysis and Computation, Numerical Analysis and Scientific Computing, Oceanography, Systems Biology
Coral transplantation attaches fragments to a structure placed on the seabed, and that structure must stay put long enough for the fragments to fuse to it. We examine that requirement with an idealized model in which a transplant unit is a planar rigid body on a rigid bed under two unilateral frictional contacts, loaded through a Morison description of near-bed wave kinematics and integrated by a [...]
Interface Habitats: An Integrated Observing Strategy for Earth’s Most Dynamic and Consequential Aquatic Boundaries
Published: 2026-09-25
Subjects: Biodiversity, Climate, Earth Sciences, Life Sciences, Marine Biology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology
One line, no hard line breaks — safe to copy and paste: Interface Habitats – the dynamic boundaries where water meets land, the seafloor, the atmosphere, and ice, and where fronts, eddies, and filaments draw comparably sharp boundaries within the water itself – are among Earth's most productive, diverse, and rapidly changing ecosystems, and the site of most human interaction with aquatic [...]
Transient Events: A Rapid-Response, Multi-Platform Observing Strategy for Detecting and Understanding Abrupt Change in Aquatic Ecosystems
Published: 2026-09-25
Subjects: Biochemistry, Biodiversity, Biogeochemistry, Earth Sciences, Marine Biology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Extremes, not average conditions, increasingly govern the state of aquatic ecosystems and the risks they carry for people. Events far outside normal variability can reshape ecosystem structure and function within hours to weeks, and both the observational record and climate projections indicate such extremes are growing more frequent, more intense, and longer lasting. Whether an extreme becomes a [...]
Ocean warming and acidification alter larval development and swimming behavior in the Atlantic sea scallop, Placopecten magellanicus
Published: 2026-09-10
Subjects: Animal Sciences, Biology, Ecology and Evolutionary Biology, Life Sciences, Marine Biology
Ocean warming (OW) and ocean acidification (OA) are expected to have wide-ranging consequences for populations in marine systems caused by organism-level responses at a range of life history stages, including early larval stages. The Atlantic sea scallop, Placopecten magellanicus, is an economically important bivalve species that may be vulnerable to ocean change, but larval responses remain [...]
The Vulnerability Spiral: Compound Climate Risk Across Five Islands
Published: 2026-09-05
Subjects: Biodiversity, Earth Sciences, Environmental Monitoring, Environmental Sciences, Environmental Studies, Geographic Information Sciences, Geography, Geomorphology, Hydrology, International and Area Studies, Marine Biology, Natural Resource Economics, Nature and Society Relations, Oceanography and Atmospheric Sciences and Meteorology, Other Environmental Sciences, Other Geography, Remote Sensing, Spatial Science, Statistical Methodology, Statistical Models, Sustainability
Low islands face two threats at once: the sea rising, and the reefs and mangroves that buffer it weakening. I measured both across 5 island groups in 3 ocean basins (Maldives, Lakshadweep, Seychelles, Fiji and the Canary Islands), testing mangroves and coral reefs as separate pathways. Exposure is the share of people (WorldPop 2020) living on land at or below 1 m, on a bare earth elevation model [...]
Manufactured vulnerability in the Ganges–Brahmaputra–Meghna delta: engineered drivers and coastal displacement in south-west Bangladesh
Published: 2026-08-29
Subjects: Life Sciences, Marine Biology, Risk Analysis, Social and Behavioral Sciences
Displacement from the Ganges–Brahmaputra–Meghna delta in south-west Bangladesh is usually attributed to sea-level rise, cyclones and salinity. The evidence assembled here points to a jointly produced process, in which hazards act together with engineered landscape change, governance arrangements and the interval households spend unable to return. Peer-reviewed and grey literature for Khulna, [...]
phytoclassShiny: a Guided Workflow for Phytoplankton Pigment Chemotaxonomy
Published: 2026-08-23
Subjects: Life Sciences, Marine Biology
Estimating phytoplankton community structure using diagnostic pigment biomarkers relies on chemotaxonomic tools like CHEMTAX and the mathematical improvements of the phytoclass R package. However, phytoclass requires programming experience that limits its accessibility to non-coders. We present phytoclassShiny, a free, open-source, offline R Shiny application that guides users through a linear, [...]
Marine Heatwaves Disrupt Phytoplankton Communities Through Trait-dependent Selection
Published: 2026-05-24
Subjects: Biodiversity, Biogeochemistry, Climate, Marine Biology
Phytoplankton communities, key regulators of marine ecosystems and the global carbon cycle, are susceptible to sea surface temperature variability, such as marine heatwaves (MHWs). However, their trait-dependent responses and the resulting compositional shifts during MHWs remain poorly understood. Here, using an advanced global ocean–biogeochemical model that resolves 310 phytoplankton trait [...]
A snag for nutrient fertilization: decoupled production and export
Published: 2026-03-28
Subjects: Earth Sciences, Ecology and Evolutionary Biology, Environmental Sciences, Life Sciences, Marine Biology, Microbiology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Interest in nutrient fertilization waned after inconclusive field experiments, but has resurged. Collating Southern Ocean \textit{in-situ} observations and available fertilization simulations, we find phytoplankton primary production and organic carbon export are uncorrelated in the largest high-nutrient-low-chlorophyll (HNLC) region, while model estimates cast doubt on realistic deployments [...]
Assessing the medium-term risk to reef damage and rubble generation for the Great Barrier Reef
Published: 2026-03-06
Subjects: Atmospheric Sciences, Environmental Monitoring, Life Sciences, Marine Biology, Natural Resources and Conservation, Oceanography, Other Earth Sciences, Physical Sciences and Mathematics
Coral reef systems live in multi-hazard environments and are exposed to a wide range of disturbance events that operate at different spatial and temporal scales. We identify seven drivers derived from hazards that have and can result in reef damage in the Great Barrier Reef (GBR): waves, winds, bottom current velocity, coral bleaching, crown-of-thorns seastar outbreaks, ship groundings, and [...]
Hybrid Physics–AI Ecosystem Simulations Improve Biogeochemical Predictions in Temperate Shelf Seas
Published: 2026-02-03
Subjects: Artificial Intelligence and Robotics, Biochemistry, Biogeochemistry, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Marine Biology, Numerical Analysis and Scientific Computing, Oceanography, Planetary Biogeochemistry, Terrestrial and Aquatic Ecology
Biogeochemical models form a core part of marine forecasting and climate projections, yet they suffer from persistent biases in predicting key ecosystem variables, creating challenges across regional and global scales. To address this, we developed an AI-augmented three-dimensional hybrid framework that integrates machine-learning corrections directly into a process-based model’s productivity [...]
Diel Dynamics of Zooplankton Fecal Pellet Flux Revealed by Integrated Optical Observations and Modeling
Published: 2026-01-23
Subjects: Biogeochemistry, Life Sciences, Marine Biology, Oceanography
The contribution of sinking fecal pellets to the biological carbon pump depends on pellet properties, producer abundance, and the depth and timing of pellet production, which can be modulated by diel vertical migration. We examined diel variability in zooplankton fecal pellet flux in the subarctic Northeast Pacific using two image-based tools: the Underwater Vision Profiler (UVP5) and [...]
Coral reef commitments are largely absent from national biodiversity and climate frameworks
Published: 2025-11-21
Subjects: Biodiversity, Climate, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Marine Biology, Natural Resource Economics, Natural Resources and Conservation, Natural Resources Management and Policy, Oceanography, Other Oceanography and Atmospheric Sciences and Meteorology, Sustainability
Global agreements under the Convention on Biological Diversity (CBD) and the UN Framework Convention on Climate Change (UNFCCC) call for integrated action on biodiversity loss and climate change. Yet national implementation remains poorly understood, even for ecosystems highly vulnerable to warming, such as tropical coral reefs. Bleaching-level heat stress has affected over 85% of global reefs [...]