The climatology of the deep particle flux in the oligotrophic western North Atlantic gyre, 1978–2022

Progress In Oceanography, Journal Year: 2025, Volume and Issue: unknown, P. 103433 - 103433

Published: Feb. 1, 2025

Language: Английский

---

Bayesian Calibration for the Arctic Sea Ice Biomarker IP₂₅

Paleoceanography and Paleoclimatology, Journal Year: 2025, Volume and Issue: 40(3)

Published: March 1, 2025

Abstract Sea ice plays multiple important roles in regulating the global climate. Rapid sea loss Arctic has been documented over recent decades, yet our understanding of long‐term variability and its feedbacks remains limited by a lack quantitative reconstructions. The diatom‐derived biomarker combined with sterols produced open‐water phytoplankton index as proxy to achieve semi‐quantitative Here, we analyze compilation 600 published core‐top measurements paired brassicasterol and/or dinosterol across (sub‐)Arctic oceans calculate newln() that correlates nonlinearly concentration. Leveraging sediment trap observational studies, develop spatially varying Bayesian calibration ( BaySIC ) for ln() account non‐stationary relationship concentration other environmental drivers (e.g., surface salinity). model is fully invertible, allowing probabilistic forward modeling well inverse past bi‐directional uncertainty quantification. facilitates direct proxy‐model comparisons palaeoclimate data assimilation, providing polar constraints currently missing climate simulations enabling, first time,

Language: Английский

---

The Arctic summer microbiome across Fram Strait: Depth, longitude, and substrate concentrations structure microbial diversity in the euphotic zone

Environmental Microbiology, Journal Year: 2024, Volume and Issue: 26(2)

Published: Jan. 24, 2024

Abstract The long‐term dynamics of microbial communities across geographic, hydrographic, and biogeochemical gradients in the Arctic Ocean are largely unknown. To address this, we annually sampled polar, mixed, Atlantic water masses Fram Strait (2015–2019; 5–100 m depth) to assess microbiome composition, substrate concentrations, oceanographic parameters. Longitude depth were major determinants (~30%) community variability. Bacterial alpha diversity was highest lower‐photic polar waters. Community composition shifted from west east, with prevalence of, for example, Dadabacteriales Thiotrichales Arctic‐ Atlantic‐influenced waters, respectively. Concentrations dissolved organic carbon peaked western, compared carbohydrates chlorophyll‐maximum eastern Strait. Interannual differences due time sampling, which varied between early (June 2016/2018) late (September 2019) phytoplankton bloom stages, illustrated that resulting availability labile substrates influence bacterial dynamics. We identified 10 species clusters stable environmental correlations, representing signature populations distinct ecosystem states. In context published metagenomic evidence, our microbial‐biogeochemical inventory a key region establishes benchmark imprint climate change.

Language: Английский

---

Ice algae contributions to the benthos during a time of sea ice change: a review of supply, coupling, and fate

Frontiers in Environmental Science, Journal Year: 2024, Volume and Issue: 12

Published: Aug. 16, 2024

The polymer-facilitated flux of ice algae on Arctic shelves can initiate benthic activity and growth after the nutritionally constrained winter period. Lipid-rich are readily consumed by benthos those entering sediment benefit deposit feeders. Ice assimilated organisms cascade up multiple trophic levels within sub-web, re-entering pelagic sub web through habitat coupling species. Pelagic predators have significant ice-algal carbon signals obtained from compartment. Sympagic-pelagic-benthic is expected to weaken with ongoing sea-ice change. This review discusses phenology, quantity, quality contributions coupling, linked thinning snow cover including multi-year replacement. Predicting future between marine sub-webs requires focused research that considers markers sources.

Language: Английский

---

A Lagrangian Model‐Based Analysis of Protist Plankton Variability and Its Impact on Organic Matter Dynamics Along Transit Pathways Through the Fram Strait

Journal of Geophysical Research Oceans, Journal Year: 2024, Volume and Issue: 129(10)

Published: Oct. 1, 2024

Abstract The Arctic Ocean is characterized by substantial seasonal and inter‐annual variability, of which the sources impacts are not yet fully understood. Here, we analyze how much variability found in situ observations biogeochemical ecological variables collected at Long‐Term Ecological Research Observatory HAUSGARTEN can be explained differences physical conditions water masses passing through Fram Strait (FS). Employing a size‐based plankton ecosystem model with nine distinct size classes protist phyto‐ zooplankton, simulate standing stocks fluxes within nutrient, phytoplankton, detritus pools parcels that follow trajectories tracing opposing East‐Greenland West‐Spitsbergen currents FS. Our results agree tracers, measurements, climatological data, remote sensing observations. They show temporal developments composition, growth, export trajectory ensembles, highlighting variable affect communities' specific growth histories. study indicates 10%–72% upper column tracer concentrations observed FS attributed to parcel trajectories. maxima net primary production vertical along occurred some (spatial temporal) distance upstream sites sampling. This shows Lagrangian modeling helps clarify complex biogeochemical‐ecological relationships highly dynamic systems such as FS, urgently needed understand role climate change carbon cycle.

Language: Английский

---

Release of ballast material during sea-ice melt enhances carbon export in the Arctic Ocean

PNAS Nexus, Journal Year: 2024, Volume and Issue: 3(4)

Published: Feb. 17, 2024

Globally, the most intense uptake of anthropogenic carbon dioxide (CO

Language: Английский

---