A 13C labelling study on carbon fluxes in Arctic plankton communities under elevated CO2 levels

The effect of CO2 on carbon fluxes in Arctic plankton communities was investigated during the 2010 EPOCA mesocosm study in Ny Ålesund, Svalbard. Nine mesocosms were set up with initial pCO2 levels ranging from 185 to 1420 μatm for 5 weeks. 13C labelled bicarbonate was added at the start of the experiment to follow the transfer of carbon from dissolved inorganic carbon (DIC) into phytoplankton, bacteria, total particulate organic carbon (POC), zooplankton, and settling particles. Polar lipid derived fatty acids (PLFA) were used to trace carbon dynamics of phytoplankton and bacteria and allowed distinction of two groups of phytoplankton: phyto I (autotrophs) and phyto II (mixotrophs). Nutrients were added on day 13. A nutrient-phytoplankton-zooplankton-detritus model amended with 13C dynamics was constructed and fitted to the data to quantify uptake rates and carbon fluxes in the plankton community during the phase prior to nutrient addition (phase 1, days 0–12). During the first 12 days, a phytoplankton bloom developed that was characterized by high growth rates (0.87 days−1) for phyto I and lower growth rates (0.18 days−1) for phyto II. A large part of the carbon fixed by phytoplankton (~31%) was transferred to bacteria, while mesozooplankton grazed only ~6% of the production. After 6 days, the bloom collapsed and part of the organic matter subsequently settled into the sediment traps. The sedimentation losses of detritus in phase 1 were low (0.008 days−1) and overall export was only ~7% of production. Zooplankton grazing and detritus sinking losses prior to nutrient addition were sensitive to CO2: grazing decreased with increasing CO2, while sinking increased. Phytoplankton production increased again after nutrient addition on day 13. Although phyto II showed initially higher growth rates with increasing CO2 (days 14–22), the overall production of POC after nutrient addition (phase 2, days 14–29) decreased with increasing CO2. Significant sedimentation occurred towards the end of the experiment (after day 24) and much more material settled down in the sediment traps at low CO2

Biopsy Sampling in Upper Gastrointestinal Endoscopy : A Survey from 10 Tertiary Referral Centres across Europe

Funding Information: A. Link reports grants from European Commission “Eu-ropäischer Fond für regionale Entwicklung” (EFRE), outside the submitted work. In Lithuania the work was partly supported by Lithuanian Research Council Grant no APP-2/2016. In Latvia, the methodological support was made available from the project lzp-2018/1-0135. This work was also supported by the NIHR Oxford Biomedical Research Centre (The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care). In Barcelona, we thank the CERCA Programme/Generalitat de Catalunya for the support. Publisher Copyright: © 2020 The Author(s) Published by S. Karger AG, Basel.Background: Guidelines give robust recommendations on which biopsies should be taken when there is endoscopic suggestion of gastric inflammation. Adherence to these guidelines often seems arbitrary. This study aimed to give an overview on current practice in tertiary referral centres across Europe. Methods: Data were collected at 10 tertiary referral centres. Demographic data, the indication for each procedure, endoscopic findings, and the number and sampling site of biopsies were recorded. Findings were compared between centres, and factors influencing the decision to take biopsies were explored. Results: Biopsies were taken in 56.6% of 9,425 procedures, with significant variation between centres (p < 0.001). Gastric biopsies were taken in 43.8% of all procedures. Sampling location varied with the procedure indication (p < 0.001) without consistent pattern across the centres. Fewer biopsies were taken in centres which routinely applied the updated Sydney classification for gastritis assessment (46.0%), compared to centres where this was done only upon request (75.3%, p < 0.001). This was the same for centres stratifying patients according to the OLGA system (51.8 vs. 73.0%, p < 0.001). More biopsies were taken in centres following the MAPS guidelines on stomach surveillance (68.1 vs. 37.1%, p < 0.001). Biopsy sampling was more likely in younger patients in 8 centres (p < 0.05), but this was not true for the whole cohort (p = 0.537). The percentage of procedures with biopsies correlated directly with additional costs charged in case of biopsies (r = 0.709, p = 0.022). Conclusion: Adherence to guideline recommendations for biopsy sampling at gastroscopy was inconsistent across the participating centres. Our data suggest that centre-specific policies are applied instead.publishersversionPeer reviewe

Global rates of water-column denitrification derived from nitrogen gas measurements

Biologically available nitrogen (N) limits phytoplankton growth over much of the ocean. The rate at which N is removed from the contemporary ocean by denitrifying bacteria is highly uncertain 1-3. Some studies suggest that N losses exceed inputs 2,4-6; others argue for a balanced budget 3,7,8. Here, we use a global ocean circulation model to simulate the distribution of N 2 gas produced by denitrifying bacteria in the three main suboxic zones in the open ocean. By fitting the model to measured N 2 gas concentrations, we infer a globally integrated rate of water-column denitrification of 66 ±6 Tg N yr -1. Taking into account isotopic constraints on the fraction of denitrification occurring in the water column versus marine sediments, we estimate that the global rate of N loss from marine sediments and the oceanic water column combined amounts to around 230 ±60 Tg N yr -1. Given present estimates of N input rates, our findings imply a net loss of around 20 ± 70 Tg of N from the global ocean each year, indistinguishable from a balanced budget. A balanced N budget, in turn, implies that the marine N cycle is governed by strong regulatory feedbacks. © 2012 Macmillan Publishers Limited. All rights reserved

Energy neutral and circular cooperation of farmers: work package research file

n the work package described in this report, members are investigating whether a cooperative of farmers can become self-sufficient in energy and fertilization by using manure and organic waste flows in combination with anaerobic fermentation. The aim is to link the nutrient cycle (from manure to digestate to green fertilizer consisting of, for example, nitrate, phosphate, potassium, and trace elements) to a self-sufficient energy system, by the combined production of electricity, green gas, green fuels, and green fertilizers. Within this research such a system is called a circular multi commodity system (CMCS). In effect linking, the nutrient cycle with an energy production chain. In addition, other energy sources and sinks can also play a role in the system such as wind, solar PV and storage (e.g. batteries or hydrogen). For this symbiosis of production techniques to succeed in practice, intensive cooperation between arable farmers and dairy farmers is needed. Farmers supply part of the input from the biofermenter and receive green fertilizers at the end of the process, which are used as a substitute for fertilizer. The case is based on a cooperative of farmers with a minimal geographical spread and maximum diversity in type of business. In this way, the current waste and nutrient chain is being replaced by a more sustainable and closed cycle. This could provide significant environmental benefits: reduction of the environmental impact through the use of fertilizer, reduction of dependence on fossil raw materials, and reduction of CO2 emissions

Energy neutral and circular cooperation of farmers:work package research file

n the work package described in this report, members are investigating whether a cooperative of farmers can become self-sufficient in energy and fertilization by using manure and organic waste flows in combination with anaerobic fermentation. The aim is to link the nutrient cycle (from manure to digestate to green fertilizer consisting of, for example, nitrate, phosphate, potassium, and trace elements) to a self-sufficient energy system, by the combined production of electricity, green gas, green fuels, and green fertilizers. Within this research such a system is called a circular multi commodity system (CMCS). In effect linking, the nutrient cycle with an energy production chain. In addition, other energy sources and sinks can also play a role in the system such as wind, solar PV and storage (e.g. batteries or hydrogen). For this symbiosis of production techniques to succeed in practice, intensive cooperation between arable farmers and dairy farmers is needed. Farmers supply part of the input from the biofermenter and receive green fertilizers at the end of the process, which are used as a substitute for fertilizer. The case is based on a cooperative of farmers with a minimal geographical spread and maximum diversity in type of business. In this way, the current waste and nutrient chain is being replaced by a more sustainable and closed cycle. This could provide significant environmental benefits: reduction of the environmental impact through the use of fertilizer, reduction of dependence on fossil raw materials, and reduction of CO2 emissions

Seasonal and interannual variation of the phytoplankton and copepod dynamics in Liverpool Bay

The seasonal and interannual variability in the phytoplankton community in Liverpool Bay between 2003 and 2009 has been examined using results from high frequency, in situ measurements combined with discrete samples collected at one location in the bay. The spring phytoplankton bloom (up to 29.4 mg chlorophyll m?3) is an annual feature at the study site and its timing may vary by up to 50 days between years. The variability in the underwater light climate and turbulent mixing are identified as key factors controlling the timing of phytoplankton blooms. Modelled average annual gross and net production are estimated to be 223 and 56 g C m?2 year?1, respectively. Light microscope counts showed that the phytoplankton community is dominated by diatoms, with dinoflagellates appearing annually for short periods of time between July and October. The zooplankton community at the study site is dominated by copepods and use of a fine mesh (80 ?m) resulted in higher abundances of copepods determined (up to 2.5×106 ind. m?2) than has previously reported for this location. There is a strong seasonal cycle in copepod biomass and copepods greater than 270 ?m contribute less than 10% of the total biomass. Seasonal trends in copepod biomass lag those in the phytoplankton community with a delay of 3 to 4 months between the maximum phytoplankton biomass and the maximum copepod biomass. Grazing by copepods exceeds net primary production at the site and indicates that an additional advective supply of carbon is required to support the copepod community

Cold-Water Coral in Aquaria: Advances and Challenges. A Focus on the Mediterranean

Knowledge on basic biological functions of organisms is essential to understand not only the role they play in the ecosystems but also to manage and protect their populations. The study of biological processes, such as growth, reproduction and physiology, which can be approached in situ or by collecting specimens and rearing them in aquaria, is particularly challenging for deep-sea organisms like cold-water corals. Field experimental work and monitoring of deep-sea populations is still a chimera. Only a handful of research institutes or companies has been able to install in situ marine observatories in the Mediterranean Sea or elsewhere, which facilitate a continuous monitoring of deep-sea ecosystems. Hence, today’s best way to obtain basic biological information on these organisms is (1) working with collected samples and analysing them post-mortem and / or (2) cultivating corals in aquaria in order to monitor biological processes and investigate coral behaviour and physiological responses under different experimental treatments. The first challenging aspect is the collection process, which implies the use of oceanographic research vessels in most occasions since these organisms inhabit areas between ca. 150 m to more than 1000 m depth, and specific sampling gears. The next challenge is the maintenance of the animals on board (in situations where cruises may take weeks) and their transport to home laboratories. Maintenance in the home laboratories is also extremely challenging since special conditions and set-ups are needed to conduct experimental studies to obtain information on the biological processes of these animals. The complexity of the natural environment from which the corals were collected cannot be exactly replicated within the laboratory setting; a fact which has led some researchers to question the validity of work and conclusions drawn from such undertakings. It is evident that aquaria experiments cannot perfectly reflect the real environmental and trophic conditions where these organisms occur, but: (1) in most cases we do not have the possibility to obtain equivalent in situ information and (2) even with limitations, they produce relevant information about the biological limits of the species, which is especially valuable when considering potential future climate change scenarios. This chapter includes many contributions from different authors and is envisioned as both to be a practical “handbook” for conducting cold-water coral aquaria work, whilst at the same time offering an overview on the cold-water coral research conducted in Mediterranean laboratories equipped with aquaria infrastructure. Experiences from Atlantic and Pacific laboratories with extensive experience with cold-water coral work have also contributed to this chapter, as their procedures are valuable to any researcher interested in conducting experimental work with cold-water corals in aquaria. It was impossible to include contributions from all laboratories in the world currently working experimentally with cold-water corals in the laboratory, but at the conclusion of the chapter we attempt, to our best of our knowledge, to supply a list of several laboratories with operational cold-water coral aquaria facilities