| 1. |
- Friedrich, Jana, et al.
(författare)
-
Investigating hypoxia in aquatic environments: diverse approaches to addressing a complex phenomenon
- 2014
-
Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper we provide an overview of new knowledge on oxygen depletion (hypoxia) and related phenomena in aquatic systems resulting from the EU-FP7 project HYPOX (“In situ monitoring of oxygen depletion in hypoxic ecosystems of coastal and open seas, and landlocked water bodies”, www.hypox.net). In view of the anticipated oxygen loss in aquatic systems due to eutrophication and climate change, HYPOX was set up to improve capacities to monitor hypoxia as well as to understand its causes and consequences. Temporal dynamics and spatial patterns of hypoxia were analyzed in field studies in various aquatic environments, including the Baltic Sea, the Black Sea, Scottish and Scandinavian fjords, Ionian Sea lagoons and embayments, and Swiss lakes. Examples of episodic and rapid (hours) occurrences of hypoxia, as well as seasonal changes in bottom-water oxygenation in stratified systems, are discussed. Geologically driven hypoxia caused by gas seepage is demonstrated. Using novel technologies, temporal and spatial patterns of watercolumn oxygenation, from basin-scale seasonal patterns to meter-scale sub-micromolar oxygen distributions, were resolved. Existing multidecadal monitoring data were used to demonstrate the imprint of climate change and eutrophication on long-term oxygen distributions. Organic and inorganic proxies were used to extend investigations on past oxygen conditions to centennial and even longer timescales that cannot be resolved by monitoring. The effects of hypoxia on faunal communities and biogeochemical processes were also addressed in the project. An investigation of benthic fauna is presented as an example of hypoxia-devastated benthic communities that slowly recover upon a reduction in eutrophication in a system where naturally occurring hypoxia overlaps with anthropogenic hypoxia. Biogeochemical investigations reveal that oxygen intrusions have a strong effect on the microbially mediated redox cycling of elements. Observations and modeling studies of the sediments demonstrate the effect of seasonally changing oxygen conditions on benthic mineralization pathways and fluxes. Data quality and access are crucial in hypoxia research. Technical issues are therefore also addressed, including the availability of suitable sensor technology to resolve the gradual changes in bottom-water oxygen in marine systems that can be expected as a result of climate change. Using cabled observatories as examples, we show how the benefit of continuous oxygen monitoring can be maximized by adopting proper quality control. Finally, we discuss strategies for state-of-the-art data archiving and dissemination in compliance with global standards, and how ocean observations can contribute to global earth observation attempts.
|
|
| 2. |
- Gourdon, Pontus Emanuel, 1978, et al.
(författare)
-
Optimized in vitro and in vivo expression of proteorhodopsin: A seven-transmembrane proton pump
- 2008
-
Ingår i: Protein Expression and Purification. - : Elsevier BV. - 1096-0279 .- 1046-5928. ; 58:1, s. 103-113
-
Tidskriftsartikel (refereegranskat)abstract
- Proteorhodopsin is an integral membrane light-harvesting proton pump that is found in bacteria distributed throughout global surface waters. Here, we present a protocol for functional in vitro production of pR using a commercial cell-free synthesis system yielding 1.0 mg purified protein per milliliter of cell lysate. We also present an optimized protocol for in vivo over-expression of pR in Escherichia coli, and a two-step purification yielding 5 mg of essentially pure functional protein per liter of culture. Both approaches are straightforward, rapid, and easily scalable. Thus either may facilitate the exploitation of pR for commercial biotechnological applications. Finally, the implications of some observations of the in vitro synthesis behavior, as well as preliminary results towards a structural determination of pR are discussed.
|
|
| 3. |
- Hektor, Erik, 1978, et al.
(författare)
-
Med fokus på koldioxidproblematiken - Tre systemperspektiv på koldioxidavskiljning och flexibla mekanismer
- 2005
-
Ingår i: Arbetsnotat Program Energisystem. - Linköping : Linköpings universitet, Institutionen för konstruktions- och produktionsteknik, Energisystem.
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Arbetet är uppdelat i tre delar. De första två behandlar koldioxidavskiljning och lagring, CCS, varav den första främst är en intervjustudie som analyserar debatten om CCS i Sverige. Den andra är en ekonomisk utvärdering av CCS vid implementering i massabruk. Massabruken är för övrigt en av Sveriges största källor till koldioxidutsläpp. Den tredje och sista delen behandlar Kyotoprotokollets flexibla mekanismer, nämligen joint implementation, JI, och clean development mechanism, CDM, utifrån hypotesen att stora delar av de beräknade ekonomiska vinsterna kan komma att ätas upp på grund av transaktionskostnader.
|
|
| 4. |
- Stigebrandt, Anders, 1942, et al.
(författare)
-
An Experiment with Forced Oxygenation of the Deepwater of the Anoxic By Fjord, Western Sweden
- 2015
-
Ingår i: Ambio. - : Springer Netherlands. - 0044-7447 .- 1654-7209. ; 44:1, s. 42-54
-
Tidskriftsartikel (refereegranskat)abstract
- In a 2.5-year-long environmental engineering experiment in the By Fjord, surface water was pumped into the deepwater where the frequency of deepwater renewals increased by a factor of 10. During the experiment, the deepwater became long-term oxic, and nitrate became the dominating dissolved inorganic nitrogen component. The amount of phosphate in the water column decreased by a factor of 5 due to the increase in flushing and reduction in the leakage of phosphate from the sediments when the sediment surface became oxidized. Oxygenation of the sediments did not increase the leakage of toxic metals and organic pollutants. The bacterial community was the first to show changes after the oxygenation, with aerobic bacteria also thriving in the deepwater. The earlier azoic deepwater bottom sediments were colonized by animals. No structural difference between the phytoplankton communities in the By Fjord and the adjacent Havsten Fjord, with oxygenated deepwater, could be detected during the experiment.
|
|
| 5. |
- Vernersson, Tore V, 1968, et al.
(författare)
-
Wheel tread damage – a numerical study of railway wheel tread plasticity under thermomechanical loading
- 2010
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - 0954-4097 .- 2041-3017. ; 224:5, s. 435-443
-
Tidskriftsartikel (refereegranskat)abstract
- A numerical study is presented where the impact of simultaneous thermal and mechanical loading on a railway wheel tread, as imposed by braking and rolling contact, is reported. A comparison is made of two-dimensional (2D) and 3D finite-element simulations of the thermomechanical problem featuring a material model that accounts for thermal expansion and plastic deformations. It is found that 2D simulations give unrealistic predictions of plastic deformations. The 3D simulations demonstrate a significant influence of the thermal loading also in cases of rather moderate temperature increases. In particular, the combination of thermal loading and high traction is found to be very detrimental.
|
|
