Influence of Ocean Acidification on a Natural Winter-to-Summer Plankton Succession : First Insights from a Long-Term Mesocosm Study Draw Attention to Periods of Low Nutrient Concentrations

Every year, the oceans absorb about 30% of anthropogenic carbon dioxide (CO2) leading to a re-equilibration of the marine carbonate system and decreasing seawater pH. Today, there is increasing awareness that these changes-summarized by the term ocean acidification (OA)-could differentially affect the competitive ability of marine organisms, thereby provoking a restructuring of marine ecosystems and biogeochemical element cycles. In winter 2013, we deployed ten pelagic mesocosms in the Gullmar Fjord at the Swedish west coast in order to study the effect of OA on plankton ecology and biogeochemistry under close to natural conditions. Five of the ten mesocosms were left unperturbed and served as controls (similar to 380 mu atm pCO(2)), whereas the others were enriched with CO2-saturated water to simulate realistic end-of-the-century carbonate chemistry conditions (mu 760 mu atm pCO(2)). We ran the experiment for 113 days which allowed us to study the influence of high CO2 on an entire winter-to-summer plankton succession and to investigate the potential of some plankton organisms for evolutionary adaptation to OA in their natural environment. This paper is the first in a PLOS collection and provides a detailed overview on the experimental design, important events, and the key complexities of such a "long-term mesocosm" approach. Furthermore, we analyzed whether simulated end-of-the-century carbonate chemistry conditions could lead to a significant restructuring of the plankton community in the course of the succession. At the level of detail analyzed in this overview paper we found that CO2-induced differences in plankton community composition were non-detectable during most of the succession except for a period where a phytoplankton bloom was fueled by remineralized nutrients. These results indicate: (1) Long-term studies with pelagic ecosystems are necessary to uncover OA-sensitive stages of succession. (2) Plankton communities fueled by regenerated nutrients may be more responsive to changing carbonate chemistry than those having access to high inorganic nutrient concentrations and may deserve particular attention in future studies.Peer reviewe

Influence of Knitting and Material Parameters on the Quality and Reliability of Knitted Conductor Tracks

Many electronic textile (e-textile) applications require a stretchable basis, best achieved through knitted textiles. Ideally, conductive structures can be directly integrated during the knitting process. This study evaluates the influence of several knitting and material parameters on the resistance of knitted conductive tracks after the knitting process and after durability testing. The knitting speed proves to be of little influence, while the type of conductive thread used, as well as the knitting pattern both impact the resistance of the knitted threads and their subsequent reliability considerably. The presented research provides novel insights into the knitting process for conductive yarns and possible applications and shows that choosing suitable material and processing methods can improve the quality and robustness of knitted e-textiles

Methyl-end desaturases in the common ragworm demonstrate unique activities enabling the production of various omega-3 polyunsaturated fatty acids via multiple pathways

Trabajo presentado en el ISSFAL 14th International Congress, celebrado en modalidad virtual del 10 al 14 de mayo de 2021.Isolation and functional characterisation of methyl-end (ωx) desaturases from the common ragworm Hediste diversicolo

Unique fatty acid desaturase capacities uncovered in Hediste diversicolor illustrate the roles of aquatic invertebrates in trophic upgrading

Omega-3 (ω3 or n-3) long-chain polyunsaturated fatty acids (PUFA) including eicosapentaenoic acid and docosahexaenoic acid (DHA), play physiologically important roles in vertebrates. These compounds have long been believed to be originated almost exclusively from aquatic (mostly marine) single-cell organisms. Yet, a recent study has discovered that many invertebrates possess a type of enzymes called methyl-end desaturases (ωx) that enables them to endogenously produce n-3 long-chain PUFA and could make a significant contribution to production of these compounds in the marine environment. Polychaetes are major components of benthic fauna and thus important to maintain a robust food web as a recycler of organic matter and a prey item for higher trophic level species like fish. In the present study, we investigated the ωx enzymes from the common ragworm Hediste diversicolor, a common inhabitant in sedimentary littoral ecosystems of the North Atlantic. Functional assays of the H. diversicolor ωx demonstrated unique desaturation capacities. An ω3 desaturase mediated the conversion of n-6 fatty acid substrates into their corresponding n-3 products including DHA. A further enzyme possessed unique regioselectivities combining both ω6 and ω3 desaturase activities. These results illustrate that the long-chain PUFA biosynthetic enzymatic machinery of aquatic invertebrates such as polychaetes is highly diverse and clarify that invertebrates can be major contributors to fatty acid trophic upgrading in aquatic food webs.This study was funded through the project IMPROMEGA of the Ministry of Science, Innovation and Universities, Spanish Government (grant no. RTI2018-095119-B-I00, MCIU/AEI/FEDER, UE). N.K. was funded by the Japan Society for the Promotion of Science through Grant-in-Aid for JSPS Fellows (grant no. 16J06812). İ.G. received funding from the Ministry of National Education, Republic of Turkey. A.O. was funded by the Commonwealth Scholarship Commission (grant no. NGCS-2014-438) in the UK. A.M.M. acknowledges the Norwegian Research Council project POLYCHAETE (grant no. 280836) for funding.Peer reviewe

Plankton responses to ocean acidification: The role of nutrient limitation

In situ mesocosm experiments on the effect of ocean acidification (OA) are an important tool for investigating potential OA-induced changes in natural plankton communities. In this study we combined results from various in-situ mesocosm studies in two different ocean regions (Arctic and temperate waters) to reveal general patterns of plankton community shifts in response to OA and how these changes are modulated by inorganic nutrient availability. Overall, simulated OA caused an increase in phytoplankton standing stock, which was more pronounced in smaller-sized taxa. This effect on primary producers was channelled differently into heterotroph primary consumers depending on the inorganic nutrient availability. Under limiting conditions, bacteria and micro-heterotrophs benefited with inconsistent responses of larger heterotrophs. During nutrient replete periods, heterotrophs were in general negatively affected, although there was an increase of some mesozooplankton developmental stages (i.e. copepodites). We hypothesize that changes in phytoplankton size distribution and community composition could be responsible for these food web responses

Risk-related short-term clinical outcomes after transcatheter aortic valve implantation and their impact on early mortality: an analysis of claims-based data from Germany

Objectives We aimed to define and assess risk-specific adverse outcomes after transcatheter aortic valve implantation (TAVI) in an all-comers patient population based on German administrative claims data. Methods Administrative claims data of patients undergoing transvascular TAVI between 2017 and 2019 derived from the largest provider of statutory health-care insurance in Germany were used. Patients’ risk profile was assessed using the established Hospital Frailty Risk (HFR) score and 30-day adverse events were evaluated. Multivariable logistic regression models were applied to investigate the relation of patients’ risk factors to clinical outcomes and, subsequently, of clinical outcomes to mortality. Results A total of 21,430 patients were included in the analysis. Of those, 51% were categorized as low-, 37% as intermediate-, and 12% as high-risk TAVI patients according to HFR score. Whereas low-risk TAVI patients showed low rates of periprocedural adverse events, TAVI patients at intermediate or high risk suffered from worse outcomes. An increase in HFR score was associated with an increased risk for all adverse outcome measures. The strongest association of patients’ risk profile and outcome was present for cerebrovascular events and acute renal failure after TAVI. Independent of patients’ risk, the latter showed the strongest relation with early mortality after TAVI. Conclusions Differentiated outcomes after TAVI can be assessed using claims-based data and are highly dependent on patients’ risk profile. The present study might be of use to define risk-adjusted outcome margins for TAVI patients in Germany on the basis of health-insurance data

Development and Validation of a Dispatcher Identification Algorithm for Stroke Emergencies

Background and Purpose— Recent innovations such as CT installation in ambulances may lead to earlier start of stroke-specific treatments. However, such technically complex mobile facilities require effective methods of correctly identifying patients before deployment. We aimed to develop and validate a new dispatcher identification algorithm for stroke emergencies. Methods— Dispatcher identification algorithm for stroke emergencies was informed by systematic qualitative analysis of the content of emergency calls to ambulance dispatchers for patients with stroke or transient ischemic attack (N=117) and other neurological (N=39) and nonneurological (N=51) diseases (Part A). After training of dispatchers, sensitivity and predictive values were determined prospectively in patients admitted to Charité hospitals by using the discharge diagnosis as reference standard (Part B). Results— Part A: Dysphasic/dysarthric symptoms (33%), unilateral symptoms (22%) and explicitly stated suspicion of stroke (47%) were typically identified in patients with stroke but infrequently in nonstroke cases (all &lt;10%). Convulsive symptoms (41%) were frequent in other neurological diseases but not strokes (3%). Pain (26%) and breathlessness (31%) were often expressed in nonneurological emergencies (6% and 7% in strokes). Part B: Between October 15 and December 16, 2010, 5774 patients were admitted by ambulance with 246 coded with final stroke diagnoses. Sensitivity of dispatcher identification algorithm for stroke emergencies for detecting stroke was 53.3% and positive predictive value was 47.8% for stroke and 59.1% for stroke and transient ischemic attack. Of all 275 patients with stroke dispatcher codes, 215 (78.5%) were confirmed with neurological diagnosis. Conclusions— Using dispatcher identification algorithm for stroke emergencies, more than half of all patients with stroke admitted by ambulance were correctly identified by dispatchers. Most false-positive stroke codes had other neurological diagnoses. </jats:sec

KOSMOS 2013 Gullmar Fjord long-term mesocosm study: Mesozooplankton abundance

Ocean acidification (OA) is one of the major symptoms of the current increase in atmospheric CO2. Here, we present results from a mesocosm experiment carried out during 113 days in the Gullmar Fjord, Skagerrak coast of Sweden, studying plankton responses to predicted end-of-century pCO2 levels. Abundances of both copepods (Pseudocalanus acuspes, Temora longicornis, and Oithona similis) and hydromedusae (Hybocodon prolifer and Aglantha digitale) responded to pCO2. Furthermore, stage-specific pCO2 sensitivities were detected in copepods, copepodites being the most sensitive stage

Ocean acidification effects on mesozooplankton community development: Results from a long-term mesocosm experiment.

Ocean acidification may affect zooplankton directly by decreasing in pH, as well as indirectly via trophic pathways, where changes in carbon availability or pH effects on primary producers may cascade up the food web thereby altering ecosystem functioning and community composition. Here, we present results from a mesocosm experiment carried out during 113 days in the Gullmar Fjord, Skagerrak coast of Sweden, studying plankton responses to predicted end-of-century pCO2 levels. We did not observe any pCO2 effect on the diversity of the mesozooplankton community, but a positive pCO2 effect on the total mesozooplankton abundance. Furthermore, we observed species-specific sensitivities to pCO2 in the two major groups in this experiment, copepods and hydromedusae. Also stage-specific pCO2 sensitivities were detected in copepods, with copepodites being the most responsive stage. Focusing on the most abundant species, Pseudocalanus acuspes, we observed that copepodites were significantly more abundant in the high-pCO2 treatment during most of the experiment, probably fuelled by phytoplankton community responses to high-pCO2 conditions. Physiological and reproductive output was analysed on P. acuspes females through two additional laboratory experiments, showing no pCO2 effect on females' condition nor on egg hatching. Overall, our results suggest that the Gullmar Fjord mesozooplankton community structure is not expected to change much under realistic end-of-century OA scenarios as used here. However, the positive pCO2 effect detected on mesozooplankton abundance could potentially affect biomass transfer to higher trophic levels in the future