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Giant Submarine Landslide on the East Antarctic Margin During the Plio-Pleistocene
No full textA giant submarine landslide complex is reported on the George V margin of East Antarctic continental rise. Such landslides are imaged on seismic profiles that display evidence of basal glide planes and headwall scarps. A longitudinal seismic transect, and correlation to nearby drill sites suggest the slide was formed after the early Pliocene. To our knowledge, it is the largest submarine landslide ever identified on the Antarctic margin, with approximately 2,300 km3 of sediments evacuated from the shelf. We propose potential triggers for this slide, including weak layers, fluid and isostatic rebound following ice sheet retreat, although hypothesis relating to the processes has to be tested by direct stratigraphic data. Given the size of the landslide, an improved understanding of whether it was formed during a single event or more gradually during a prolonged interval is critical to evaluate whether Antarctic submarine geohazards may exist in a rapidly changing climates.
Key Points
A giant submarine landslide complex is the first to be discovered on the East Antarctic margin, adjacent to the Wilkes Subglacial Basin
Timing of slope failure potentially can be linked to the Pliocene-Pleistocene glacial variance
Submarine landslide failure processes are influenced by sediment deposition, weak layers, and fluid or gas presence
Plain Language Summary
We present the new discovery of a giant submarine landslide on the east Antarctic margin in front of the Wilkes Subglacial Basin, a major drainage region of the East Antarctic Ice Sheet (EAIS). To our knowledge, it is the largest reported submarine landslide along the Antarctic margin, affecting an area of c. 23, 000 km2, with approximately 2,300 km3 of sediments evacuated from the continental shelf, a similar scale to the well-documented Storegga Slide on the Norwergian margin. We propose that the primary factors driving the remobilization of sediment in the form of submarine landslides are linked to the deposition of weak layers, the presence of subseafloor fluids, and rebound of the shelf and the oversteepening of the margin caused by substantial glacier melting in warm climates. Our results suggests that EAIS variance during the Pliocene-Pleistocene ice age cycles has made this region suspectable to submarine landslides, and determining the triggers for such events is critical to understanding future Antarctic submarine geohazards related to the EAIS dynamics under future warming scenarios
2. Wochenbericht L25-10
No full textForschungsexpedition L2510 Helgoland – 5. bis 23. Juli 2025
Zweiter Wochenberich
Complementary genetic and epigenetic changes facilitate rapid adaptation to multiple global change stressors
No full textTo persist under unprecedented rates of global change, populations can adapt or acclimate. However, how these resilience mechanisms interact, particularly the role of epigenetic variation in long-term adaptation, is unknown. To address this gap, we experimentally evolved the foundational marine copepod Acartia tonsa for 25 generations under ocean acidification, warming, and their combination and then measured epigenomic, genomic, and transcriptomic responses. We observed clear and consistent epigenomic and genomic divergence between treatments, with epigenomic divergence concentrated in genes related to stress response and the regulation of transposable elements. However, epigenetic and genetic changes were inversely related and occurred in different regions of the genome; levels of genetic differentiation (FST) were up to 2.5× higher in regions where methylation did not differ between treatments compared to regions with significant methylation changes. This negative relationship between epigenetic and genetic divergence could be driven by local inhibition of one another or distinct functional targets of selection. Finally, epigenetic divergence was positively, though weakly, associated with gene expression divergence, suggesting that epigenetic changes may facilitate phenotypic change. Taken together, these results suggest that unique, complementary genetic and epigenetic mechanisms promote resilience to global change
40Ar/39Ar dating reveals over 30 million years of plume-ridge interaction formed the Rio Grande Rise
No full textThe Rio Grande Rise (RGR) oceanic plateau exhibits distinctly broad morphology compared to the linear, age-progressive Walvis Ridge (WR), despite both originating from the Tristan-Gough (T-G) plume. New 40Ar/39Ar ages (84–41 Ma) from RGR demonstrate prolonged coeval formation with WR at the Mid-Atlantic Ridge (MAR) during a ridge-centered plume configuration. These plume-ridge interactions coincided with a temporary microplate eventually incorporated into the South American Plate, explaining RGR’s broader spatial distribution. Backtracking reveals that absolute plate motion and southward plume drift shut off excess magma supply when the T-G plume moved south of large lateral MAR offsets, ending volcanism on the South American plate around 52 Ma—later than previously estimated. Although RGR’s erupted volume matches large igneous provinces, magmatic production rates were moderate, resembling modern-day Iceland rather than high-flux terrestrial large igneous provinces. This supports a ridge-centered plume origin over a high-flux magma pulse, demonstrating how plume-ridge configuration and microplate tectonics controlled the evolutionary divergence of these related South Atlantic volcanic features
KIMERA - Artificial intelligence for seabed mapping and marine spatial planning - A case study in the Clarion-Clipperton Zone
No full textScientific literature on carbon dioxide removal revealed as much larger through AI-enhanced systematic mapping
No full textCarbon dioxide removal plays an important role in any strategy to limit global warming to well below 2 °C. Keeping abreast with the scientific evidence using rigorous evidence synthesis methods is an important prerequisite for sustainably scaling these methods. Here, we use artificial intelligence to provide a comprehensive systematic map of carbon dioxide removal research. We find a total of 28,976 studies on carbon dioxide removal—3–4 times more than previously suggested. Growth in research is faster than for the field of climate change research as a whole, but very concentrated in specific areas—such as biochar, certain research methods like lab and field experiments, and particular regions like China. Patterns of carbon dioxide removal research contrast with trends in patenting and deployment, highlighting the differing development stages of these technologies. As carbon dioxide removal gains importance for the Paris climate goals, our systematic map can support rigorous evidence synthesis for the IPCC and other assessments
University Bremen Student Training Cruises: Advanced Marine Geophysical Survey Project, Marine Geophysical Field Exercise - Cruise No. AL620/1+2+3, September 11 2024 – September 24 2024,Kiel (Germany) – Kiel (Germany), GeophysPracUB
No full textThe student training cruises of the Faculty of Geosciences at the University of Bremen took place
in autumn 2024 during the Cruise AL620 with RV ALKOR. The cruise was dedicated to master
and bachelor students, but also used to demonstrate state-of-the-art marine geophysical data acquisition
to early-career scientists. Furthermore, new devices were tested during the cruise, thereby
showing the students new techniques of marine geophysical measurements.
The master students took part in the frame of the course “Advanced marine geophysical survey
project”, which is part of the module “Field and Lab Practice” within the internationally oriented
postgraduate study program Master of Science "Marine Geosciences". The module is mandatory
for students in the first year of the curriculum. The data collected during the cruise can be used for
small scientific projects carried out by the students after the cruise. Additionally, the collected data
are available for master theses.
For the bachelor students, the cruise is the “Marine geophysical field exercise” as part of the
module “Geoscientific Field Competence”. This module is mandatory for bachelor students in
their second academic year. The “Marine geophysical field exercise” is especially addressed to
students which enrolled the core subject “Exploration Geophysics”. Within this core subject, the
module “Marine Geophysics” is a major component of the second academic year of the students,
and the content communicated in the module „Marine Geophysik“ should be applied during the
cruise. The collected seismic data are used by the participating students in the third academic year
in the course “Structural Imaging”. Within the frame of this course, seismic data processing and
interpretation are taught utilizing data collected during the RV ALKOR cruise.
During the cruise seismo-acoustic data were collected by means of a multichannel seismic system,
a multibeam system, a sidescan sonar, and the hull mounted echosounders SES2000 and
EK80. Additionally, magnetic and CTD measurements were carried out during stations
Coccolithophore abundance and production and their impacts on particulate inorganic carbon cycling in the western North Pacific
No full textCoccolithophores are globally distributed, calcifying phytoplankton that play an important role in the marine carbon cycle through their contribution to the carbonate pump. However, limited knowledge of their biogeography and environmental drivers hinders our ability to predict the response of the marine carbonate pump to climate change. Here, we investigated coccolithophore abundance, species composition, coccolithophore-derived calcium carbonate (CaCO3 as calcite), and particulate inorganic carbon (PIC) concentrations in the upper water column of the western North Pacific Ocean. Sampling was conducted along a meridional transect spanning the oligotrophic subtropical gyre and the nutrient-rich Kuroshio–Oyashio transition region. Our results show that Umbellosphaera tenuis is the numerically dominant coccolithophore species in the subtropical gyre, while Emiliania huxleyi and Syracosphaera spp. dominated in the transition region. The coccolithophore community composition exhibited significant depth- and latitude-dependent variations. On average, coccolithophore calcite contributed 79 ± 27 % of the total CaCO3 standing stock in Niskin bottle samples from the euphotic zone, with a higher contribution observed in the subtropical gyre (91 ± 30 %) compared to the Kuroshio–Oyashio transition region (70 ± 24 %). This pattern was further supported by size-fractionated PIC data from in situ pump samples, with the small size fraction (1–51 µm) contributing 76 ± 11 % of the total PIC (> 1 µm) in the subtropical gyre, compared to 67 ± 13 % in the transition region. During the sampling period, coccolithophore CaCO3 production rates ranged from 0.8 to 2.1 mmol m−2 d−1, averaging 1.5 ± 0.7 mmol m−2 d−1 in the subtropical gyre and 1.2 ± 0.4 mmol m−2 d−1 in the transition region. These findings highlight the critical role of coccolithophores in the pelagic CaCO3 cycle, particularly in oligotrophic ocean waters, and emphasize the need for improved mechanistic understanding of their distribution and calcification dynamics in a changing ocean
The chromosomal genome sequence of the sponge Crambe crambe (Schmidt, 1862) and its associated microbial metagenome sequences
No full textWe present a genome assembly from an individual Crambe crambe (Porifera; Demospongiae; Poecilosclerida; Crambeidae). The host genome sequence is 143.20 megabases in span. Most of the assembly is scaffolded into 18 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 19.53 kilobases in length. Several symbiotic prokaryotic genomes were assembled as MAGs, including two relevant sponge symbionts, the Candidatus Beroebacter blanensis/AqS2 clade (Tethybacterales, Gammaproteobacteria) of LMA sponges, and the widely distributed archaeal Nitrosopumilus sp. clade
