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CMIP6 Models agree on similar carbon cycle feedbacks between enhancing terrestrial and marine carbon sinks
No full textCarbon dioxide removal (CDR) is a crucial component of climate mitigation required to reach international climate targets. However, gaps exist in our understanding of the responses and feedbacks of the Earth system to the deployment of CDR. In this study, we compare two complementary approaches that enhance the terrestrial and marine carbon sinks with afforestation and reforestation (A/R) and ocean alkalinity enhancement (OAE), respectively, under the high emission scenario SSP5-8.5. Eight CMIP6 Earth system models are utilized, enabling a quantification of both inter-model and internal variability. By mid-century, simulated large-scale deployment of A/R and OAE individually reduces atmospheric CO2 concentrations by up to 20 ppm. For both methods, while carbon removal from the atmosphere is robust, it is difficult to detect the effects on global mean temperature, posing challenges for monitoring, reporting and verification of mitigation efforts. To quantify the carbon cycle feedbacks, we define the carbon cycle feedback ratio of A/R (OAE) as the ratio of changes in the marine (terrestrial) sink to changes in the terrestrial (marine) sink. We show that the carbon cycle feedback ratios of A/R and OAE have similar magnitudes, which is -16% and -13%, respectively. Moreover, although inter-model differences of the simulated amounts of carbon removal due to A/R are large, the corresponding carbon cycle feedback ratios of A/R are similar
Multidisciplinary teaching cruise MNF-bioc-301 Plankton along the Baltic Sea salinity gradient, Cruise No. AL618, August 18th – August 30th 2024, Kiel (Germany) – Kiel (Germany); MNF-bioc-301
No full textThe multidisciplinary teaching cruise AL618 was part of the curriculum of the master “Biological
Oceanography” at the Christian-Albrechts-University Kiel and the GEOMAR Helmholtz Centre
for Ocean Research. During this mandatory part of the MNF-bioc-301 module the students were
able to gain hands-on experience of the scientific operation on-board a modern multidisciplinary
research vessel. Methods in physical, biological and chemical oceanography were taught based on
biodiversity changes in several functional plankton groups along the Baltic Sea salinity gradient
as a main subject. The students performed tasks such as deploying state-of-the-art measuring and
sampling gear, data and sample collection as well as first on-board analyses and curation of data
and samples for later use. The on-board analyses included taxonomic identification, measurements
and counts of plankton organisms, and chlorophyll A concentrations and recording of CTD
profiles. Further samples were collected for later analyses during other practical courses in the
master curriculum such as seawater samples for eDNA and viral plankton analyses. The work with
the crew onboard ALKOR was outstanding
The archaeal class Nitrososphaeria is a key component of the reproductive microbiome in sponges during gametogenesis
No full textSponge-associated microbes play fundamental roles in regulating their hosts' physiology, yet their contribution to sexual reproduction has been largely overlooked. Most studies have concentrated on the proportion of the microbiome transmitted from parents to offspring, providing little evidence of the putative microbial role during gametogenesis in sponges. Here, we use 16S rRNA gene analysis to assess whether the microbial composition of five gonochoristic sponge species differs between reproductive and non-reproductive individuals and correlate these changes with their gametogenic stages. In sponges with mature oocytes, reproductive status did not influence either beta or alpha microbial diversity. However, in two of the studied species, Geodia macandrewii and Petrosia ficiformis, which presented oocytes at the previtellogenic stage, significant microbial composition changes were detected between reproductive and non-reproductive individuals. These disparities were primarily driven by differentially abundant taxa affiliated with the Nitrososphaeria archaeal class in both species. We speculate that the previtellogenic stages are more energetically demanding, leading to microbial changes due to the phagocytosis of microbes to meet nutritional demands during this period. Supporting our hypothesis, we observed significant transcriptomic differences in G. macandrewii, mainly associated with the immune system, indicating potential changes in the sponge's recognition system. Overall, we provide new insights into the possible roles of sponge microbiomes during reproductive periods, potentially uncovering critical interactions that support reproductive success.IMPORTANCEOur research explores the fascinating relationship between sponges and their resident microbes, focusing specifically on how these microbes might influence sponge reproduction. Sponges are marine animals known for their complex and beneficial partnerships with various microbes. While previous studies have mainly looked at how these microbes are passed from parent sponges to their offspring, our study is among the first to examine how microbial communities change during the different stages of sponge reproduction. By analyzing the microbial composition in five sponge species, we discovered that significant changes occur in species with premature oocytes, suggesting that microbes may play a crucial role in providing the necessary nutrients during early egg development. This work not only enhances our understanding of sponge biology but also opens up new avenues for studying how microbes support the reproductive success of their hosts in marine environments
FAIR Data – Base for a Living Lab in MULTI-MAREX
No full textFAIR Data form the base for a Living Lab in MULTI-MAREX. This poster rise the awareness for Metadata and provides practical approach of Data management with MULTI-MAREX along the FAIR data lifecycle
Notes on Parameterized Energy Pathways in the Ocean: Insights From Stochastic and Deterministic Kinetic Energy Injection
No full textAccurately representing ocean dynamics across interacting scales remains a challenge in numerical modeling. This study examines mesoscale eddy parameterization in eddy‐permitting ocean models by incorporating novel stochastic perturbations and comparing them with a well‐tested dynamic kinetic energy backscatter scheme. Momentum dissipation through eddy viscosity, a key aspect at such model resolutions, causes excessive dissipation not only at the grid scale but across all scales, including energy‐containing ones. This necessitates methods like dynamic backscatter to counteract energy loss and restore variability. Stochastic perturbations provide an alternative by reinjecting energy and capturing small‐scale variability. Using a double‐gyre FESOM2 configuration, we assess two stochastic forcing schemes, applied with and without dynamic backscatter. The stochastic perturbations are generated using linear inverse modeling based on a high‐resolution reference simulation. Both stochastic methods improve simulated dynamics, particularly heat distribution and kinetic energy, though they are less effective at large scales than dynamic backscatter. Contrary to expectations, combining stochastic forcing with dynamic backscatter does not yield substantial improvements. Moreover, none of the schemes significantly enhances mean kinetic energy in the jet region, suggesting unresolved dynamics at this resolution despite increased eddy‐kinetic energy (EKE). A comprehensive scale analysis, including kinetic energy production, transfer, dissipation, and spectra, highlights distinct energy pathways. Energy injection by dynamic backscatter directly increases kinetic energy, while stochastic perturbations enhance potential energy conversion and subsequent transfer to EKE. These findings emphasize the need for carefully designed energy injection patterns aligned with flow dynamics to improve parameterizations at eddy‐permitting resolutions.
Plain Language Summary
We explore ways to make ocean simulations more accurate by focusing on mesoscale eddies — whirlpools of water spanning tens to hundreds of kilometers. We test two methods: one associated with stochastic forcing, which adds random movements to mimic missing small scale flow variations, and one called dynamic kinetic energy backscatter, which boosts kinetic energy at larger scales. Using a computer model, we study how these methods affect ocean dynamics at resolutions where mesoscale eddies are only partially represented. Our results show that stochastic forcing helps to improve aspects like heat distribution but is not as effective as dynamic backscatter in enhancing kinetic energy at larger scales. Combining these methods may enhance the representation of ocean dynamics but their efficiency, when used together, was also assessed through additional diagnostics, highlighting that they do not act together optimally. These results help us to better understand how small scale processes interact with larger scales and how new methods of representing them need to be devised.
Key Points
Implementation of two stochastic forcings that meet balance constraints to reinject missing energy into coarse‐resolution simulations
Stochastic energy injection boosts kinetic energy at small scales, while dynamic backscatter spreads it more broadly across scales
Cross‐scale energy fluxes, production and dissipation are crucial for evaluating the effectiveness of parameterizations for mesoscale eddie
The risk of pathogenicity and antibiotic resistance in deep-sea cold seep microorganisms
No full textDeep-sea cold seeps host high microbial biomass and biodiversity that thrive on hydrocarbon and inorganic compound seepage, exhibiting diverse ecological functions and unique genetic resources. However, potential health risks from pathogenic or antibiotic-resistant microorganisms in these environments remain largely overlooked, especially during resource exploitation and laboratory research. Here, we analyzed 165 metagenomes and 33 metatranscriptomes from 16 global cold seep sites to investigate the diversity and distribution of virulence factors (VFs), antibiotic resistance genes (ARGs), and mobile genetic elements (MGEs). A total of 2,353 VFs are retrieved in 689 metagenome-assembled genomes (MAGs), primarily associated with indirect pathogenesis like adherence. In addition, cold seeps harbor nearly 100,000 ARGs, as important reservoirs, with high-risk ARGs (11.22%) presenting at low abundance. Compared to other environments, microorganisms in cold seeps exhibit substantial differences in VF and ARG counts, with potential horizontal gene transfer facilitating their spread. These virulome and resistome profiles provide valuable insights into the evolutionary and ecological implications of pathogenicity and antibiotic resistance in extreme deep-sea ecosystems. Collectively, these results indicate that cold seep sediments pose minimal public health risks, shedding light on environmental safety in deep-sea resource exploitation and research.IMPORTANCEIn the "One Health" era, understanding pathogenicity and antibiotic resistance in vast and largely unexplored regions like deep-sea cold seeps is critical for assessing public health risks. These environments serve as critical reservoirs where resistant and virulent bacteria can persist, adapt, and undergo genetic evolution. The increasing scope of human activities, such as deep-sea mining, is disrupting these previously isolated ecosystems, heightening the potential for microbial exchange between deep-sea communities and human or animal populations. This interaction poses a significant risk for the dissemination of resistance and virulence genes, with potential consequences for global public health and ecosystem stability. This study offers the first comprehensive analysis of virulome, resistome, and mobilome profiles in cold seep microbial communities. While cold seeps act as reservoirs for diverse ARGs, high-risk ARGs are rare, and most VFs were low risk that contribute to ecological functions. These results provide a reference for monitoring the spread of pathogenicity and resistance in extreme ecosystems, informing environmental safety assessments during deep-sea resource exploitation
Health risks status for two seaweeds of economic interest in Northwest Africa
No full textHighlights
• Health risks assessed for metal content in two economically valuable seaweeds
• All seaweed samples exceed the Cd reference threshold for human consumption
• Minimal health risk for adults at very low daily intake
• Specific sites are suitable for safe consumption by children
Abstract
Seaweeds are a promising dietary resource because they contain essential trace elements. Meristotheca senegalensis and Hypnea musciformis are two economically important seaweeds in the coastal regions of Senegal. However, they can bioaccumulate potentially toxic trace elements, such as arsenic (As), cadmium (Cd), and lead (Pb), posing potential health risks. This study analyzed the elemental composition of these seaweeds and assessed their health risks using estimated daily intake (EDI), target hazard quotients (THQ), hazard index (HI), and carcinogenic risk (CR) for both children and adults across multiple consumption levels (0.100, 2.00, 4.00, and 8.00 g day−1). Cd concentrations exceeded the toxicity thresholds in all samples, and As was the primary contributor to carcinogenic risk in nearly all scenarios. 0.100 g day−1 intake posed no significant long-term risk for adults, while it presented carcinogenic risks for children depending on the collection site. These findings emphasize the need for site-specific monitoring and the development of safety guidelines to support the sustainable integration of seaweed into food systems within Africa's emerging blue economy