Hochschule Bremerhaven

ABSTRACT The endosymbiotic jellyfish Cassiopea andromeda represents a yet untapped marine species that could be targeted as a new source for bioproducts, including food and feed. Also, the potential use of contained valuable ingredients, such as carotenoids and other antioxidants, under controlled aquaculture conditions might be a particularly promising pathway. However, this requires close knowledge about physiology and culture conditions. In this study, the effects of different stress parameters such as different light spectra, light intensities, UV and extreme temperatures on C. andromeda were investigated. The following response parameters were measured: pigments, photosynthetic efficiency, bell pulsation rate, antioxidant activity (AOA) and respiration. The carotenoid peridinin and chlorophyll a were detected as dominant light‐harvesting pigments. Three different experiments were performed. Over a four week treatment interval under four different light conditions, C. andromeda that were exposed to light spectra lacking blue color ( λ = 400–500 nm) showed a decreasing content of chlorophyll, peridinin and all other detected pigments, while photosynthetic efficiency and AOA were not affected by any light spectra changes. Critical thresholds for both photosynthetic efficiency and respiration were detected beyond 39°C. UV seemed to have a similar effect on respiration as low temperatures, while UV did not seem to significantly affect bell pulsation rate and symbiont density. This study contributes to the development of an environmentally controlled C. andromeda indoor aquaculture system, revealing optimal temperature and light regimes. Accordingly, C. andromeda holds promise as a resource for pigment production that may offer value as a supplement for functional foods and nutraceuticals.

Seafood, including crustaceans, provides a high-quality animal-origin protein source with globally increasing consumption rates. However, international seafood trade is frequently confronted with issues like commercial fraud and safety risks for human health, partly due to incorrect species identification of aquatic food products. To distinguish between crustacean species through the identification of species-specific peptides, an untargeted liquid chromatography low-resolution mass spectrometry (LC-LRMS) method was developed and validated. Programmed algorithms were applied to identify marker candidates from peptide profiles. A targeted multiple reaction monitoring (MRM) method was established to verify the suitability of selected candidates as crustacean biomarkers related to the used dataset. An additional random forest model was built to determine unknown crustacean species based on an LC-LRMS raw data training set. In total, 49 out of 150 selected peptides were identified as species-specific biomarkers based on the monitored dataset and those are able to differentiate 14 crustacean species. To further evaluate specificity, additional commercial samples from several crustacean, mussel, insect and fish species were tested. De novo sequencing of LC-LRMS and comparing high-resolution mass spectrometry (HRMS) data mostly showed similar results concerning the proposed amino acid sequence and average local confidence score. Selected peptide markers were synthesized and experimentally confirmed. The random forest model exemplarily demonstrated the correct identification in an unseen test dataset based on plurality vote. The results show the feasibility of solving authenticity questions, e.g. to identify unknown crustacean species, by applying alternative procedures without using HRMS instruments, requiring a higher effort. At the same time, the results prove that certain limitations cannot be overcome using LRMS devices.

Wagner et al. present an extensive series of distal femoral fractures managed with lateral locked plating, employing Bayesian regression to identify risk factors for nonunion. Their innovative application of posterior probabilities, as opposed to p values, represents an advancement toward a more clinically intuitive interpretation of data. With a cohort of 560 patients across 2 Level-I trauma centers, the study boasts considerable statistical power. Furthermore, the emphasis on a clinically meaningful end point—reoperation to promote union—enhances the study’s practical relevance. The authors examined patient and fracture characteristics as well as surgical variables such as screw density and coronal alignment. They found that varus or valgus malalignment and multifragmentary comminution increased the odds of nonunion; these findings reinforce biomechanical principles and echo the results of prior large cohort studies1,2. Interestingly, their study also demonstrated that a lower screw density may be protective against nonunion, suggesting that overly rigid constructs can suppress callus formation. Clinically, surgeons should prioritize alignment restoration and avoid overly rigid constructs, especially in osteoporotic bone. In complex cases, dual plating or nail-plate constructs may be justified, and primary endoprosthetic replacement is an option for elderly patients with severe comminution1,3. Successful treatment relies on mechanical stability and biological augmentation, with autologous bone grafts being preferred over substitutes and biologics. Overly rigid constructs may hinder bone-healing, whereas insufficient stability may fail to support union, necessitating a balance between mechanical and biological factors. However, there are important caveats to consider. The retrospective design spans nearly 2 decades, during which time implant technologies and surgical techniques have evolved. The study pooled native and periprosthetic fractures despite their biological and technical differences. Relying on return to the operating room as the definition of nonunion may have caused asymptomatic or nonoperatively managed nonunions to be overlooked. Several of the Bayesian credible intervals were broad, reflecting uncertainties despite the large sample sizes. Additionally, although posterior probability thresholds of >95% indicate “very strong evidence,” they essentially parallel traditional frequentist cutoffs and may mislead clinicians who are less familiar with Bayesian terminology. In context, the study reinforces—but does not drastically expand upon—established insights. Earlier cohorts emphasized systemic risk factors such as anemia, open injury, and high body mass index4. The utilization of a Bayesian framework in the study by Wagner et al. is commendable, as such a framework aligns with clinical decision-making by expressing risk in terms of probability rather than binary statements of significance. However, the effect sizes were small to moderate, reminding us that nonunion is multifactorial, and thus optimizing patient biology and surgical technique in tandem is essential. In summary, Wagner et al. deliver valuable, quantitative reinforcement of the importance of alignment and construct strategy in distal femoral fixation. Their Bayesian approach lends clarity and may influence future studies. For now, surgeons should treat these probabilities not as absolutes but as components of a broader operative planning paradigm—one in which precision in reduction and a thoughtful fixation strategy remain foundational.

Maritime ports represent concentrated emissions zones due to the simultaneous operation of manoeuvring ships, auxiliary engines and diesel-driven cargo equipment. This research applies a detailed bottom-up framework to quantify emissions arising from port operations, comparing marine diesel oil (MDO) to liquefied natural gas (LNG). A 600,000 TEU container terminal was modelled with representative vessel data and operating pro-files sourced from simulation, auxiliary load modelling and equipment duty cycles. Marine diesel operation produced approximately 595,000 tonnes per year of carbon dioxide (CO2), 6,480 tonnes per year of sulphur oxides (SOx), 276 tonnes per year of nitrogen oxides (NOx) and 14.2 tonnes per year of particulate matter (PM). Switching to LNG eliminated SOx, reduced PM by more than eighty per cent and lowered NOx by fifty-eight per cent, while cutting CO2 emissions by approximately twenty-two per cent. Yet even under LNG, the terminal would require more than 150,000 hectares of mature temperate forest to offset its residual CO2. The analysis highlights LNG as an effective transitional fuel that alleviates air quality burdens while ports invest in electrification and prepare for zero-carbon alternatives such as ammonia, hydrogen and renewable-derived synthetic fuels.

The North Sea provides valuable habitats for characteristic species and communities on different trophic levels, which have changed rapidly over the last decades, due to environmental and human impacts such as global warming, fisheries and de-eutrophication. In this study, we analyzed common trends in four characteristic epifauna communities and associated demersal fish assemblages in the south-eastern North Sea along an offshore to coastal transect (‘Tail End’, ‘Oyster Ground’, ‘Coast North Frisia’, ‘Coast East Frisia’), for which spatio-temporally overlapping epifauna and demersal fish data were available from 1998 to 2022. We applied a Dynamic Factor Analysis to identify common trends in epifauna communities and demersal fish assemblages in relation to trends of six environmental parameters and human activities. Common trends of all four epifauna communities and demersal fish assemblages indicated turning points between 2004-2006 and 2013-2017, which were related to cold winters and known regime shifts. These common trends furthermore significantly correlated with changes in winter and summer water temperature and de-eutrophication. They were also linked to lower sedimentation rates combined with stronger sea water velocities, which both led to lower mud contents. A decreasing trend in demersal trawling effort was visible in all four offshore to coastal communities and was particularly strong in the region ‘Coast East Frisia’. • 25-year time series (1998-2022) of spatio-temporally overlapping biotic and abiotic data • Covering an offshore-coastal transect in the south-eastern North Sea • Common trends in epifauna communities and fish assemblages showed regime shifts or turning points • De-eutrophication and changes in water temperature were key drivers of common trends • Changes in sediments, sea water velocity and trawling effort also influenced common trends

Background: Cardiac implantable electronic devices (CIEDs) are vital for managing arrhythmias but carry a notable risk of infection, which increases patient morbidity, mortality, and healthcare burden. This review examines current evidence on risk factors and preventive strategies for CIEDI. Methods: A structured search was performed in PubMed, Embase, and the Cochrane Library using terms such as “CIED,” “infection,” “pacemaker,” “ICD,” “infection prevention,” “biofilm,” “antibiotic prophylaxis,” and “antibiotic-eluting envelope.” Study selection followed PRISMA guidelines. Results: For well-established topics, recommendations are based on high-quality evidence from the literature. In areas with limited CIED-specific data, evidence from related surgical fields was considered, and expert consensus was used to guide recommendations. Conclusions: This review offers practical guidance for clinicians on CIED infection prevention, addressing gaps not previously covered in existing guidelines.

• Ecological plausibility of species-distribution models is often neglected • Traditional optimal performance metrics often yield implausible models • Temperature response should comply with the ecological niche concept • Performance metrics based on decadal changes are better for climate studies • Temperature bell-shape responses provide better models for climate projections Species Distribution Models (SDMs) are widely used tools for studying potential climate-induced shifts in species distribution to support future marine spatial planning. However, the ecological plausibility of selected models is often neglected, particularly in marine ecosystems, resulting in potentially misleading outcomes, especially when climate effects are of concern. In this study we modeled the distribution of 11 commercial fish species in the North Sea using 57 years of observations and 60 SDMs with various degrees of freedom and aimed to improve the ecological plausibility of SDMs by evaluating common model selection techniques. Model performance was evaluated using deviances obtained with three cross-validation designs, Akaike Information Criterion, median absolute deviation and percentage of local mismatch. We identified top performing models based on consistent good scores of those metrics and assessed the ecological plausibility of all models. Specifically, we tested whether the modeled temperature response curve aligned with the ecological niche concept, i.e. having a bell shape within the plausible temperature range for each species, where the highest habitat suitability should relate to optimal conditions. The tested performance metrics often yielded conflicting outcomes and selected models with implausible temperature response curves that had poor extrapolation skills in temperature space and, thus, may result in unreliable predictions under climate change. Building on our findings, we provide recommendations for future SDM applications to improve their accuracy, ecological plausibility and predictive skills in climate-related studies.