Climate-driven changes in underwater irradiance and primary productivity in an Antarctic fjord (Potter Cove, Western Antarctic Peninsula).

The West Antarctic Peninsula (WAP) is a hotspot of climate warming, evidencing glacier retreat and a decrease in the fast-ice duration. This study provides a > 30-y time-series (1987-2022) on annual and seasonal air temperatures in Potter Cove (Isla 25 de Mayo/King George Island). It investigates the interaction between warming, glacial melt, fast-ice and the underwater conditions (light, salinity, temperature, turbidity) over a period of 10 years along the fjord axis (2010-2019), and for the first time provides a unique continuous underwater irradiance time series over 5 years (2014-2018).

Recent methane surges reveal heightened emissions from tropical inundated areas.

Record breaking atmospheric methane growth rates were observed in 2020 and 2021 (15.2±0.5 and 17.

How does the coral microbiome mediate its natural host fitness under climate stress conditions? Physiological, molecular, and biochemical mechanisms.

Although the symbiotic partnership between corals and algal endosymbionts has been extensively explored, interactions between corals, their algal endosymbionts and microbial associates are still less understood. Screening the response of natural microbial consortiums inside corals can aid in exploiting them as markers for dysbiosis interactions inside the coral holobiont. The coral microbiome includes archaea, bacteria, fungi, and viruses hypothesized to play a pivotal vital role in coral health and tolerance to heat stress condition via different physiological, biochemical, and molecular mechanisms.

Functional characterization of the second feedback loop in the circadian clock of the Antarctic krill Euphausia superba.

Background: The Antarctic krill Euphausia superba is a keystone species in the Southern Ocean ecosystem. This crustacean has an ancestral clock whose main components have been identified and characterized in the past few years. However, the second feedback loop, modulating clock gene expression through two transcription factors, VRI and PDP1, has yet to be described.

The International Bathymetric Chart of the Arctic Ocean Version 5.0.

Knowledge about seafloor depth, or bathymetry, is crucial for various marine activities, including scientific research, offshore industry, safety of navigation, and ocean exploration. Mapping the central Arctic Ocean is challenging due to the presence of perennial sea ice, which limits data collection to icebreakers, submarines, and drifting ice stations. The International Bathymetric Chart of the Arctic Ocean (IBCAO) was initiated in 1997 with the goal of updating the Arctic Ocean bathymetric portrayal.

Origin and intra-annual variability of vertical microplastic fluxes in Fram Strait, Arctic Ocean.

Microplastic (MP) pollution has reached the remotest areas of the globe, including the polar regions. In the Arctic Ocean, MPs have been detected in ice, snow, water, sediment, and biota, but their temporal dynamics remain poorly understood. To better understand the transport pathways and drivers of MP pollution in this fragile environment, this study aims to assess MPs (≥ 11 μm) in sediment trap samples collected at the HAUSGARTEN observatory (Fram Strait) from September 2019 to July 2021.

Raised water temperature enhances benthopelagic links via intensified bioturbation and benthos-mediated nutrient cycling.

Sediment reworking by benthic infauna, namely bioturbation, is of pivotal importance in expansive soft-sediment environments such as the Wadden Sea. Bioturbating fauna facilitate ecosystem functions such as bentho-pelagic coupling and sediment nutrient remineralization capacities. Yet, these benthic fauna are expected to be profoundly affected by current observed rising sea temperatures.

Recent global temperature surge intensified by record-low planetary albedo.

In 2023, the global mean temperature soared to almost 1.5 kelvin above the preindustrial level, surpassing the previous record by about 0.17 kelvin.

Circumpolar and Regional Seascape Drivers of Genomic Variation in a Southern Ocean Octopus.

Understanding how ecological, environmental and geographic features influence population genetic patterns provides crucial insights into a species' evolutionary history, as well as their vulnerability or resilience under climate change. In the Southern Ocean, population genetic variation is influenced across multiple spatial scales ranging from circum-Antarctic, which encompasses the entire continent, to regional, with varying levels of geographic separation. However, comprehensive analyses testing the relative importance of different environmental and geographic variables on genomic variation across these scales are generally lacking in the Southern Ocean.

The value of information in predicting harmful algal blooms.

Environmental decision-making is inherently subject to uncertainty. However, decisions are often urgent, and whether to take direct action or invest in collecting additional data beforehand is pervasive. To make this trade-off explicit, the value of information (VoI) theory offers a powerful decision analytic tool to quantify the expected benefit of resolving uncertainty in a decision context.

The Hunga Tonga-Hunga Ha'apai volcanic barometric pressure pulse and meteotsunami travel recorded in several Antarctic stations.

The Hunga Tonga-Hunga/Hunga-Ha'apai eruption on January 15, 2022 sent off a plume of ash material up to the stratosphere and triggered a meteotsunami and barometric pressure pulse that rippled through the atmosphere and oceans all around the world. The nature of the volcanic event and its global impacts on the oceans, atmosphere, lithosphere and the cryosphere are a matter of debate. Here we present a first overview of the time travel of the sound atmospheric pressure wave through the Antarctic continent based on in situ measurements, which represented a unique event observed through the polar ice sheet during the instrumental meteorological era.

Frazil ice changes winter biogeochemical processes in the Lena River.

The ice-covered period of large Arctic rivers is shortening. To what extent will this affect biogeochemical processing of nutrients? Here we reveal, with silicon isotopes (δSi), a key winter pathway for nutrients under river ice. During colder winter phases in the Lena River catchment, conditions are met for frazil ice accumulation, which creates microzones.

Multicentennial cycles in continental demography synchronous with solar activity and climate stability.

Human population dynamics and their drivers are not well understood, especially over the long term and on large scales. Here, we estimate demographic growth trajectories from 9 to 3 ka BP across the entire globe by employing summed probability distributions of radiocarbon dates. Our reconstruction reveals multicentennial growth cycles on all six inhabited continents, which exhibited matching dominant frequencies and phase relations.

Effect of particles from wind turbine blades erosion on blue mussels Mytilus edulis.

Offshore wind farms (OWFs) pose new anthropogenic pressures on the marine environment as the erosion of turbine blades release organic and inorganic substances with potential consequences for marine life. In the present study, possible effects of the released particles and their chemical constituents on the metabolic profile of the blue mussel, Mytilus edulis, were investigated, utilizing H NMR spectroscopy. In the lab, mussels were exposed for 7 and 14 days to different concentrations (10 and 40 mg L) of microplastic (MP) particles which were derived from cryo-milled rotor blade coatings and core materials (glass fiber polymer, GFP).

Chromosome-level genome assemblies and genetic maps reveal heterochiasmy and macrosynteny in endangered Atlantic Acropora.

Background: Over their evolutionary history, corals have adapted to sea level rise and increasing ocean temperatures, however, it is unclear how quickly they may respond to rapid change. Genome structure and genetic diversity contained within may highlight their adaptive potential.

Results: We present chromosome-scale genome assemblies and linkage maps of the critically endangered Atlantic acroporids, Acropora palmata and A.

Towards high-resolution water isotope analysis in ice cores using laser ablation - cavity ring-down spectroscopy.

A new micro-destructive technique for high-resolution water isotope analysis of ice samples using a Laser Ablation (LA) system coupled with a Cavity Ring Down Spectrometer (CRDS) is presented. This method marks the first time water isotope analysis is conducted directly on the ice, bypassing the traditional steps of melting and vaporizing the ice sample, thanks to the direct transition of ice into water vapour through the laser ablation process. A nanosecond ArF laser ablation system (193 nm) with an integrated two-volume ablation chamber was successfully coupled to a CRDS analyzer, utilizing nitrogen as the carrier gas.

Discovery of deep-sea coral symbionts from a novel clade of marine bacteria with severely reduced genomes.

Microbes perform critical functions in corals, yet most knowledge is derived from the photic zone. Here, we discover two mollicutes that dominate the microbiome of the deep-sea octocoral, Callogorgia delta, and likely reside in the mesoglea. These symbionts are abundant across the host's range, absent in the water, and appear to be rare in sediments.