| 51. |
- Berggren, Martin
(författare)
-
An experimentalist's approach to global limnology: filling the gaps in process understanding of large-scale organic matter transformations (invited)
- 2016
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the classical plenary lecture ‘Global limnology’ (J.A. Downing, 2007, SIL in Montréal), a new holistic direction for freshwater science was pointed out, focused at upscaling of limnological processes to planet Earth. Since then, the literature on the global importance of freshwater networks, especially as routes for carbon degassing, burial and transport, has grown explosively. This has been reflected in increased use of large-scale models, intensified collection of field survey data and in a revival of holistic concepts such as the River continuum. However, I here argue that the field has come to a point where mechanistic understanding of basic ecosystem processes again is limiting the development. Recent experimental work on bacterial and photochemical degradation processes is used to exemplify how small-scale reductionist studies can fundamentally challenge the picture painted by current large-scale models, especially with respect to the reactivity of dissolved organic matter along the land-sea continuum. Finally, I discuss how the apparent antagonism between holistic and reductionist studies can be overcome by efforts to better represent mechanistic process understanding in models.
|
|
| 52. |
- Berggren, Martin, et al.
(författare)
-
Climate Impact on Dissolved Organic Carbon Composition in a North-Temperate Peatland and Recipient Surface Water
- 2024
-
Ingår i: Journal of Geophysical Research: Biogeosciences. - 2169-8953. ; 129:6
-
Tidskriftsartikel (refereegranskat)abstract
- Climate may regulate dissolved organic carbon (DOC) composition across the peat-water interface, but experimental evidence is scarce. We manipulated the climate in peatland and recipient surface water mesocosms to reflect four different climate warming scenarios. In half of the mesocosms, the water level was managed to avoid drought, after which responses were recorded during two annual cycles. It was hypothesized that warming and drought increase the aromaticity and humic-like fluorescence character of DOC, and that this change propagate to recipient waters. Pore water DOC concentrations increased with temperature and peaked in hydrologically unmanaged mesocosms. Aromaticity increased as expected after drought in the warmest scenario (+3.2°C), but the overall evidence for hypothesized changes in DOC aromaticity and fluorescence composition (%) was limited. In managed warming scenarios, one aromatic humic component expectedly increased together with microbially derived humic fluorescence, whereas two other humic-like components decreased. In the unmanaged mesocosms which were exposed to drought, water level exerted an overriding control of humic DOC; for example, as the microbially derived humic fluorescence diminished after drought in all climate scenarios. In the surface water recipients, warming had nearly no impact on humic-like fluorescence, but there were decreases in protein-like fluorescence. Overall, this experiment revealed no conclusive support for the hypothesized aromatization and humification of peatland-derived DOC in response to drought or warming. Nonetheless, both factors increase the quantity of DOC in peatland pore waters and affect composition in complex ways, calling for further investigation of chemical and functional traits of peatland DOC in a changing environment.
|
|
| 53. |
|
|
| 54. |
|
|
| 55. |
- Berggren, Matz S., 1950, et al.
(författare)
-
Xandarovula patula (Gastropoda: Ovulidae) new to Scandinavia.
- 2011
-
Ingår i: Marine Biodiversity Records. - 1755-2672. ; 4, s. 1-4
-
Tidskriftsartikel (refereegranskat)abstract
- In August 2009 six specimens of the ovulid gastropod Xandarovula patula (Pennant, 1777) (formerly known as Simnia patula Pennant, 1777), were found in dredge samples from a locality west of Smögen in western Sweden (58°22′N 11°05′E). In June and November 2010 a total of three specimens of the same species were found in dredge samples from near Svelgen Bridge, Øygarden, Hordaland, western Norway (60°27 ′N 04°57 ′E). Several small colonies of the presumed prey species, Alcyonium digitatum Linnaeus, 1758 and Tubularia indivisa Linnaeus, 1758, were found in the same dredge hauls. Xandarovula patula has been recorded from the Atlantic coast of southern Spain to the western end of the English Channel, with scattered records from the west coasts of Ireland and Britain, as far north as the Orkneys. More recently it has been reported from most Irish coasts, several parts of the Scottish coast and also from some places in the North Sea. Until now there have been no confirmed records from Scandinavian waters. The specimens recorded here may indicate recent immigration of a southern species due to warmer water temperatures.
|
|
| 56. |
- Berggren, Magnus, et al.
(författare)
-
Solid-state droplet laser made from an organic blend with a conjugated polymer emitter
- 1997
-
Ingår i: Advanced Materials. - : Wiley-VCH Verlag Berlin. - 0935-9648 .- 1521-4095. ; 9:12, s. 968-
-
Tidskriftsartikel (refereegranskat)abstract
- Lasers based on organic materials have been produced with a wide range of resonator design and in a variety of geometries. A new strategy is presented for fabricating permanently near-spherical whispering gallery mode (WGM) lasers from a blend of PPV7 and PBD (see Figure) by a melting and resolidification process. The thresholds and quality factors of these resonators are estimated and discussed.
|
|
| 57. |
- Berggren, Martin, et al.
(författare)
-
Systematic microbial production of optically active dissolved organic matter in subarctic lake water
- 2020
-
Ingår i: Limnology and Oceanography. - : Association for the Sciences of Limnology and Oceanography (ASLO). - 0024-3590 .- 1939-5590. ; 65:5
-
Tidskriftsartikel (refereegranskat)abstract
- The ecology and biogeochemistry of lakes in the subarctic region are particularly sensitive to changes in the abundance and optical properties of dissolved organic matter (DOM). External input of colored DOM to these lakes is an extensively researched topic, but little is known about potential reciprocal feedbacks between the optical properties of DOM and internal microbial processes in the water. We performed 28-day dark laboratory incubation trials on water from 101 subarctic tundra lakes in northern Sweden, measuring the microbial decay of DOM and the resulting dynamics in colored (CDOM) and fluorescent (FDOM) DOM components. While losses in dissolved oxygen during the incubations corresponded to a 20% decrease in mean DOM, conversely the mean CDOM and total FDOM increased by 22% and 30%, respectively. However, the patterns in microbial transformation of the DOM were not the same in all lakes. Notably, along the gradient of increasing ambient CDOM (water brownness), the lakes showed decreased microbial production of protein-like fluorescence, lowered DOM turnover rates and decreasing bacterial growth per unit of DOM. These trends indicate that browning of subarctic lakes systematically change the way that bacteria interact with the ambient DOM pool. Our study underscores that there is no unidirectional causal link between microbial processes and DOM optical properties, but rather reciprocal dependence between the two.
|
|
| 58. |
|
|
| 59. |
- Bergqvist, Johanna, et al.
(författare)
-
Att införa skriftliga betygskriterier : en pedagogisk satsning vid Humanistiska och teologiska fakulteterna vid Lunds universitet
- 2015
-
Konferensbidrag (refereegranskat)abstract
- Att implementera ett övergripande policybeslut i en kunskapsintensiv organisation är komplext, mångfacetterat och långtifrån enkelt (Senge 2006; Trowler 2005). Ämnestraditioner och olika lokala akademiska mikrokulturer (Roxå & Mårtensson 2015) påverkar hur organisationens beslut tas emot, tolkas, och omsätts i praktik. HT-fakulteterna vid Lunds universitet har sjösatt ett stort pedagogiskt utvecklingsprojekt med syfte att alla fakulteternas kurser ska ha skriftliga betygskriterier. Skriftliga betygskriterier är emellertid inte till mycket glädje för varken studenter eller lärare om de är ogenomtänkta eller bara hamnar i skrivbordslådan (Bergqvist 2015; O’Donovan et al. 2006). För att undvika det har lyhördhet gentemot fakulteternas undervisande personal varit viktig, liksom att ta till vara deras erfarenheter, inte minst vid skrivandet av en vetenskapligt underbyggd handbok (Bergqvist 2015). Riktlinjer som tagits fram har eftersträvats att vara så smidiga och praxisnära som möjligt. Tid har getts för det hela att ta form, landa och så småningom implementeras vid institutionerna. Implementeringsfasen har nu inletts och löper 2017 ut. I detta papper vill vi dela med oss av våra tankar och erfarenheter kring pedagogiska och strukturella beaktanden i samband med genomförandet av ett stort högskolepedagogiskt utvecklingsprojekt vid Lunds universitet, och om att göra detta med utgångspunkt i den lokala undervisningskulturen.
|
|
| 60. |
|
|
