| 1. |
- Jürgens, Klaus, et al.
(författare)
-
[Indirect parameters: Ecosystem] Microbial community and processes
- 2021
-
Ingår i: Climate change in the baltic sea. - Helsinki : Helsinki Commission (HELCOM). ; , s. 39-39
-
Bokkapitel (refereegranskat)abstract
- This overview focuses on bacterioplankton, comprising single-celled prokaryotes, i.e.,small organisms that lack a nucleus (Bacteriaand Archaea), in the water column, consuming organic carbon as an energy and carbonsource. Benthic prokaryotes and protozoa (i.e., unicellular zooplankton and zoobenthos) are also important but not included here. Bacteria are the major transformers of carbon, nitrogen, sulphur, and trace metalcycles in aquatic environments. The supply of organic carbon mainly controls bacterial biomass production. The bacterial community composition changes along the salinity andoxygen gradients of the Baltic Sea. Shifts in, e.g., food sources, temperature, and oxygen concentration result in rapid bacterioplankton community changes, with potential impact also on overall ecosystem functions, such as respiration, carbon consumption, and biomass production.
|
|
| 2. |
|
|
| 3. |
- Ramnefält, Richard, et al.
(författare)
-
Plan for centralized data portal for mesocosm
- 2021
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A centralized international data tool for primary experimental data is developed to achieve Open science with Open data. This will promote meta-analyses across environments and times. A prerequisite is harmonized data entry, with a reliable quality. Simultaneously, the primary data shell shall provide support for individual research groups by easy entering of primary data, integrated quality assurance tools, including open data archiving, facilitating evaluation, and reporting of research data. Time for data administration should be minimized and scientific work optimized.The demands and expectations of the primary data shell have been collected by three workshops and a questionnaire. We use the term “shell” to reflect its implementation as a layer filtering primary data prior to archiving in an existing EU-data base for research data.By adopting an interactive and inclusive (i.e. agile) approach this plan will be an organic document, evolving by multiple iterations between research groups and developers. In the first steps of the development, the model of the computer components required was defined and a sketch created, defining its key parts. The user interface will evolve in iterations in later stages of the development process.The aim is to create a user-friendly, versatile and logical data tool. Trust in the primary data shell from the end users is crucial for a successful implementation. Users should feel that they have control over and access to their own data, safe archiving with reliable back-up routines lowering barriers for data sharing. We also use a generic approach enabling easy administration of common experimental research data from any subject field.
|
|
| 4. |
- Ramnefält, Richard, et al.
(författare)
-
Report of centralised data portal launch
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A pilot version of a web interface primary data shell has been developed. The shell was pre-tested by a selected group of dedicated partners, improved and launched for testing by partners in the whole AQUACOSM-plus community. By a couple of introductory meetings, partners were shown the procedure to enter a mesocosm experiment and add primary data. Partners had the opportunity to test the platform for 2,5 months and give feed-back with suggestions of improvements. Suggestions for improvements were noted from the partners and additional improvements were furthermore identified by the task group itself. No major requirements of changes of the basic structure of the primary data shell were requested. Most suggested improvements for the six prioritized variables are planned to be remedied within the project period. The need of resources to develop a fully operational shell will be presented in the final report from this task.
|
|
| 5. |
- Vass, Máté, et al.
(författare)
-
Co-occurrences enhance our understanding of aquatic fungal metacommunity assembly and reveal potential host–parasite interactions
- 2022
-
Ingår i: FEMS Microbiology Ecology. - : Oxford University Press. - 0168-6496 .- 1574-6941. ; 98:11
-
Tidskriftsartikel (refereegranskat)abstract
- Our knowledge of aquatic fungal communities, their assembly, distributions and ecological roles in marine ecosystems is scarce. Hence, we aimed to investigate fungal metacommunities of coastal habitats in a subarctic zone (northern Baltic Sea, Sweden). Using a novel joint species distribution model and network approach, we quantified the importance of biotic associations contributing to the assembly of mycoplankton, further, detected potential biotic interactions between fungi–algae pairs, respectively. Our long-read metabarcoding approach identified 493 fungal taxa, of which a dominant fraction (44.4%) was assigned as early-diverging fungi (i.e. Cryptomycota and Chytridiomycota). Alpha diversity of mycoplankton declined and community compositions changed along inlet–bay–offshore transects. The distributions of most fungi were rather influenced by environmental factors than by spatial drivers, and the influence of biotic associations was pronounced when environmental filtering was weak. We found great number of co-occurrences (120) among the dominant fungal groups, and the 25 associations between fungal and algal OTUs suggested potential host–parasite and/or saprotroph links, supporting a Cryptomycota-based mycoloop pathway. We emphasize that the contribution of biotic associations to mycoplankton assembly are important to consider in future studies as it helps to improve predictions of species distributions in aquatic ecosystems.
|
|
| 6. |
- Verma, Ashish, et al.
(författare)
-
Prokaryotic maintenance respiration and growth efficiency field patterns reproduced by temperature and nutrient control at mesocosm scale
- 2023
-
Ingår i: Environmental Microbiology. - : John Wiley & Sons. - 1462-2912 .- 1462-2920. ; 25:3, s. 721-737
-
Tidskriftsartikel (refereegranskat)abstract
- The distribution of prokaryotic metabolism between maintenance and growth activities has a profound impact on the transformation of carbon substrates to either biomass or CO2. Knowledge of key factors influencing prokaryotic maintenance respiration is, however, highly limited. This mesocosm study validated the significance of prokaryotic maintenance respiration by mimicking temperature and nutrients within levels representative of winter and summer conditions. A global range of growth efficiencies (0.05-0.57) and specific growth rates (0.06-2.7 d(-1)) were obtained. The field pattern of cell-specific respiration versus specific growth rate and the global relationship between growth efficiency and growth rate were reproduced. Maintenance respiration accounted for 75% and 15% of prokaryotic respiration corresponding to winter and summer conditions, respectively. Temperature and nutrients showed independent positive effects for all prokaryotic variables except abundance and cell-specific respiration. All treatments resulted in different taxonomic diversity, with specific populations of amplicon sequence variants associated with either maintenance or growth conditions. These results validate a significant relationship between specific growth and respiration rate under productive conditions and show that elevated prokaryotic maintenance respiration can occur under cold and oligotrophic conditions. The experimental design provides a tool for further study of prokaryotic energy metabolism under realistic conditions at the mesocosm scale.
|
|
| 7. |
- Verma, Ashish, et al.
(författare)
-
Prokaryotic variables from a indoor-mesocosm experiment measured during the winter in the Northern Bothnian Sea
- 2023
-
Annan publikationabstract
- The primary data was collected during the indoor-mesocosm experiment conducted in March 2020 at Umea Marine Science Centre, Umea University, Sweden situated in the Northern Bothnian Sea (63° 34ˈN, 19° 50ˈE). A full factorial experiment was set with temperature and the addition of nutrients as treatment factors with a natural pelagic food web containing all trophic levels except fish. A total of four experimental treatments were set up with three replicates each: C, control (1°C, no additions); N (1°C,+ nutrients); T (10°C, no additions) and TN (10°C, + nutrients). For each treatment, eight different samplings were done in triplicates. The variables in the data include the prokaryotic abundance (PA), growth (PG), respiration (PR), specific prokaryotic respiration (ρ), specific growth rates (µ), growth efficiency (PGE), dissolved organic carbon (DOC), total dissolved phosphorus (TDP) and total dissolved nitrogen (TDN).
|
|
| 8. |
- Vikström, Kevin, 1988-, et al.
(författare)
-
Strong Influence of Baseline Respiration in an Oligotrophic Coastal Ecosystem
- 2020
-
Ingår i: Frontiers in Marine Science. - : Frontiers Media S.A.. - 2296-7745. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Respiration is a key metabolic process in the marine environment and contemporary phytoplankton production (PhP) is commonly assumed the main driver. However, respiration in the absence of contemporary PhP, termed baseline respiration, can influence the energetics of an ecosystem and its sensitivity to hypoxia. Direct studies of baseline respiration are currently lacking. This study aims to obtain a first estimate of baseline respiration in a sub-arctic estuary and determine its contribution to plankton community respiration. Three approaches used to define baseline respiration determined the average rate to be 4.1 ± 0.1 (SE) mmol O2 m–3 d–1. A hypsographic model at the basin scale accounting for seasonal variation estimated an annual contribution of 30% baseline respiration to planktonic respiration. There was no correlation between plankton respiration and PhP, but a significant linear dependence was found with the total carbon supply from phytoplankton and riverine input. The sum of dissolved organic carbon transported by rivers, provided by both benthic and pelagic algae, could sustain 69% of the annual plankton respiration, of which as much as 25% occurred during winter. However, only 32% of the winter season respiration was explained, indicating that unknown carbon sources exist during the winter. Nitrification had a negligible (≤2.4%) effect on baseline respiration in the system. The results show that baseline respiration accounted for a significant percentage of coastal plankton respiration when allochthonous sources dominated the carbon supply, weakening the respiration-to- PhP relationship.
|
|
| 9. |
- Wikner, Evelina, 1987, et al.
(författare)
-
How the utilised SOC window in commercial Li-ion pouch cells influence battery ageing
- 2021
-
Ingår i: Journal of Power Sources Advances. - : Elsevier BV. - 2666-2485. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- In many lithium-ion battery (LIB) applications, e.g. hybrid vehicles and load-levelling storage systems, only part of the state-of-charge (SOC) range needs to be utilised. This offers the possibility to use an optimal SOC window to avoid LIB ageing. Here, a large test matrix is designed to study LIB ageing in a commercial 26 Ah pouch cell, in order to map the ageing behaviour at different SOC levels with respect to temperature and current. A quantification of the degradation modes, loss of lithium inventory (LLI), loss of active positive (LAM(PE)) and negative (LAM(NE)) electrode materials is made by analysing the change in the open circuit voltage (OCV). A key result is that lower SOC intervals significantly improved battery ageing. Even during harsh test conditions, such as high Crates and temperatures, the cells deliver more than three times the expected number of full cycle equivalents. High SOC combined with high C-rate increase ageing where the dominating ageing mechanisms are LLI, followed by LAM(PE).
|
|
| 10. |
- Wikner, Johan, Professor, 1961-, et al.
(författare)
-
Extensive prokaryotic maintenance respiration in the sea influenced by osmoregulation
- 2023
-
Ingår i: Frontiers in Marine Science. - : Frontiers Media S.A.. - 2296-7745. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Microbial respiration is the major process consuming oxygen in the biosphere. The relative energy demand from growth of biomass or maintenance activities determines the regulation of respiration with impact on how the development of hypoxia and CO2 emissions is controlled. This coupling is crucial for understanding the life history and associated ecological interactions of microorganisms. However, the knowledge of rate and regulating factors of maintenance respiration in the biosphere is limited. In this study, we demonstrated significant relationships in marine field samples where the prokaryotic specific growth rate predicts cell-specific respiration, in accordance with theory from culture models, over a 10-fold salinity range. This enables the first reported direct estimates of maintenance respiration in nature to show a 6-fold variation between 0.12-0.62 fmol O2 cell-1 d-1, comprising 29-72% of prokaryotic specific respiration. The lowest maintenance respiration occurred at salinity close to physiological osmolarity, suggesting osmoregulation as one of the more energy-consuming maintenance activities. A conservative global estimate of maintenance respiration accounted for 66% of the total prokaryotic respiration in the ocean´s mixed layer. This means that maintenance activities dominate the use of the energy generated by prokaryotic respiration in the sea, where osmoregulation is one significant energy consumer. Consequently, maintenance respiration and its regulation must be included in ecological and biogeochemical models to accurately project and manage the development of hypoxia and CO2 emissions from the ocean.
|
|
