Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2018
Forfattere
Arne StensvandSammendrag
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Sammendrag
Carbonic anhydrase (CA) plays an important physiological role in all biological systems by accelerating the interconversion of CO2 and HCO3 −. In algae, CA is essential for photosynthesis: external CA (CAext) dehydrates HCO3 −, enhancing the supply of CO2 to the cell surface, and internal CA (CAint) interconverts HCO3 − and CO2 to maintain the inorganic carbon (Ci) pool and supply CO2 to RuBisCO. We frst conducted a literature review comparing the conditions in which CA extraction and measurement have been carried out, using the commonly used Wilbur–Anderson method. We found that the assay has been widely modifed since its introduction in 1948, mostly without being optimized for the species tested. Based on the review, an optimized protocol for measuring CA in Macrocystis pyrifera was developed, which showed that the assay conditions can strongly afect CA activity. Tris–HCl bufer gave the highest levels of CA activity, but phosphate bufer reduced activity signifcantly. Bufers containing polyvinylpyrrolidone (PVP) and dithiothreitol (DTT) stabilized CA. Using the optimized assay, CAext and CAint activities were readily measured in Macrocystis with higher precision compared to the non-optimized method. The CAint activity was 2×higher than CAext, which is attributed to the Ci uptake mechanisms of Macrocystis. This study suggests that the CA assay needs to be optimized for each species prior to experimental work to obtain both accurate and precise results.
Sammendrag
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Forfattere
Anna Caroline HoleneSammendrag
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Forfattere
Kaishan Song Zhidan Wen Yijun Xu Hong Yang Lili Lyu Ying Zhao Chong Fang Yingxin Shang Jia DuSammendrag
Dissolved carbon in lakes play a vital role in the global carbon cycling. The concentration and dynamics of lake dissolved carbon can be influenced by both the surrounding landscape and a combination of physical, chemical and biological processes within the lakes themselves. From 2009 to 2016, we conducted a large-scale assessment of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in 249 lakes across a diverse range of climatic, geopedologic, topographical and hydrological conditions in five Chinese limnetic regions: the East Limnetic Region (ELR), the Northeast Limnetic Region (NLR), the Inner Mongolia-Xinjiang Limnetic Region (MXR), the Yungui Limnetic Region (YGR), and the Tibet-Qinghai Limnetic Region (TQR). We found that the density of the organic matter in the soil in the surrounding landscape plays an important role in the DOC and DIC in lake water, as was evidenced by the high DOC and DIC levels in the NLR, where the soil is respectively organically rich. Conditions in the arid and semi-arid environments (i.e. TQR and MXR) have created a number of brackish/saline lakes and here we found that, DOC and DIC levels (median: 21.79 and 93.72 mg/L, respectively) are significantly higher than those in the freshwater lakes (median: 5.80 and 29.38 mg/L). It also appears to be the case that the trophic state of freshwater lakes influences the spatial variation of DOC. This can be seen in the relationships between DOC and trophic state index (TSI) in agriculturally-dominated regions such as the ELR (R2 = 0.59, p < 0.01), NLR (R2 = 0.65, p < 0.001), and YGR (R2 = 0.78, p < 0.001). Additionally, a close relationship between DOC and DIC can be found in lake waters with different trophic states (eutrophic: slp = 0.63, R2= 0.69; mesotrophic: slp = 1.03, R2 = 0.65; oligotrophic: slp = 1.00, R2 = 0.64). This indicates that human activities influence the quantity and quality of dissolved carbon in inland water across China. This study is able to provide insights regarding the potential effects of climate change and changes in land-use upon the amount of dissolved carbon in lake water.
Forfattere
Finn-Arne HaugenSammendrag
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Forfattere
Finn-Arne HaugenSammendrag
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Forfattere
Finn-Arne HaugenSammendrag
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Forfattere
Bjørn Egil FløSammendrag
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Forfattere
Finn-Arne HaugenSammendrag
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