Browsing by Subject "temperature"

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  • Arppe, Laura; Kurki, Eija; Wooller, Matthew J.; Luoto, Tomi P.; Zajaczkowski, Marek; Ojala, Antti E. K. (2017)
    The oxygen isotope composition of chironomid head capsules in a sediment core spanning the past 5500 years from Lake Svartvatnet in southern Spitsbergen was used to reconstruct the oxygen isotope composition of lake water (O-18(lw)) and local precipitation. The O-18(lw) values display shifts from the baseline variability consistent with the timing of recognized historical climatic episodes, such as the Roman Warm Period, the Dark Ages Cold Period and the Little Ice Age'. The highest values of the record, ca. 3 parts per thousand above modern O-18(lw) values, occur at ca. 1900-1800 cal. yr BP. Three negative excursions increasing in intensity toward the present, at 3400-3200, 1250-1100, and 350-50 cal. yr BP, are tentatively linked to roughly synchronous episodes of increased glacier activity and general cold spells around the northern North Atlantic. Their manifestation in the Svartvatnet O-18(lw) record not only testify to the sensitivity and potential of high Arctic lacustrine O-18(chir) records in tracking terrestrial climate evolution but also highlight nonlinear dynamics within the northern North Atlantic hydroclimatic system. The Little Ice Age' period at 350-50 cal. yr BP displays a remarkable 8-9 parts per thousand drop in O-18(lw) values, construed to predominantly represent significantly decreased winter temperatures during a period of increased seasonal differences and extended sea ice cover inducing changes in moisture source regions.
  • Kylä-Puhju, Maria; Ruusunen, Marita; Puolanne, Eero (Elsevier, 2005)
    The activity of glycogen debranching enzyme (GDE) was studied in relation to pH value and temperature in porcine masseter and longissimus dorsi muscles. A glycogen limit dextrin was used as the substrate for GDE, and the enzyme was derived from raw meat extracts. In both muscles, the pH only weakly affected on activity of GDE at the pH values found in carcasses post-slaughter. However, the activity of GDE decreased strongly (P < 0.001) when the temperature decreased from values of 39 °C and 42 °C found just after slaughter to values of 4 °C and 15 °C found during cooling. In both muscles the activity of GDE began to fall at temperatures below 39 °C and was almost zero when the temperature decreased to below 15 °C. Thus, the activity of GDE may control the rate of glycogenolysis and glycolysis, but does not block rapid glycolysis and pH decrease when the temperature is high. This may be important in PSE meat, where the pH decreases rapidly at high temperatures, but rapid cooling could limit the activity of GDE and thus glycogenolysis. As expected, GDE was more active in the light longissimus dorsi muscle than in the dark masseter muscle.
  • Luoto, Tomi P.; Kivila, E. Henriikka; Kotrys, Bartosz; Plociennik, Mateusz; Rantala, Marttiina; Nevalainen, Liisa (2020)
    Independent Arctic records of temperature and precipitation from the same proxy archives are rare. Nevertheless, they are important for providing detailed information on long-term climate changes and temperature-precipitation relationships in the context of large-scale atmospheric dynamics. Here, we used chironomid and cladoceran fossil assemblages to reconstruct summer air-temperature and water-level changes, during the past 400 years, in a small lake located in Finnish Lapland. Temperatures remained persistently cold over the Little Ice Age (LIA), but increased in the 20th century. After a cooler phase in the 1970s, the climate rapidly warmed to the record-high temperatures of the most recent decades. The lake-level reconstruction suggested persistently wet conditions for the LIA, followed by a dry period between similar to 1910 and 1970 CE, when the lake apparently became almost dry. Since the 1980s, the lake level has returned to a similar position as during the IAA. The temperature development was consistent with earlier records, but a significant local feature was found in the lake-level reconstruction the LIA appears to have been continuously wet, without the generally depicted dry phase during the 18th and 19th centuries. Therefore, the results suggest local precipitation patterns and enforce the concept of spatially divergent LIA conditions.
  • Koskela, Elina (Helsingin yliopisto, 2019)
    Tiivistelmä/Referat – Abstract This study investigates temperature data that Posiva Oy has from the Olkiluoto and ONKALO® sites. The aim of the study was to create a unifying data classification for the existing temperature measurements, give an estimate of the initial undisturbed bedrock temperature and temperature gradient and model the temperature profiles in 3D. The thermal related issues, which the repository will undergo once in operating are significant and have fundamental contribution to the evolution of the repository, creating a need in such a study. Posiva Oy has temperature data obtained with four main methods; Geophysical drillhole loggings, Posiva flow log (PFL) measurements, thermal properties (TERO) measurements and Antares measurements. The data classification was carried out by creating a platform of quality aspects affecting the measurements. The classification was then applied for all the available data by inspecting the measurement specifics of each configuration and by observing the temperature/depth profiles with WellCad software. According to the specifics of each individual measurement the data was classified into three groups: A= the best data, recommended for further use, and which fulfils all quality criteria, B= data that should be used with reservation and which only partly fulfils quality criteria, and C= unusable data. Only data that showed no major disturbance within the temperature/depth profile (class A or B) were used in this study. All the temperature/depth data was corrected to the true vertical depth. The initial undisturbed average temperature of Olkiluoto bedrock at the deposition depth of 412 m and the temperature gradient, according to the geophysical measurements, PFL measurements (without pumping), TERO measurements and Antares measurements were found to be 10.93 ± 0.09°C and 1.47°C/100m, 10.85 ± 0.02°C and 1.43°C/100m, 10.60 ± 0.08°C and 1.65°C/100m, and 10.75°C and 1.39°C/100m, respectively. The 3D layer models presented in this study were generated by using Leapfrog Geo software. From the model a 10.5 – 12°C temperature range was obtained for the deposition depth of 412 – 432 m. The models indicated clear temperature anomalies in the volume of the repository. These anomalies showed relationship between the location of the major brittle fault zones (BFZ) of Olkiluoto island. Not all observed anomalies could be explained by a possible cause. Uncertainties within the modelling phase should be taken into consideration in further interpretations. By combining an up-to-date geological model and hydraulic model of the area to the temperature models presented here, a better understanding of the temperature anomalies and a clearer over all understanding of the thermal conditions of the planned disposal location will be achieved. Based on this study a uniform classification improves the usability of data and leads into a better understanding of the possibilities and weaknesses within it. The initial bedrock temperature and the temperature gradient in Olkiluoto present thermally a relatively uniform formation. The estimates of the initial bedrock temperatures and the temperature gradient presented in this study, endorse previous estimates. Presenting the classified temperature data in 3D format generated good results in the light of thermal dimensioning of Olkiluoto by showing distinct relationships between previously created brittle fault zone (fracture zone) models. The views and opinions presented here are those of the author, and do not necessarily reflect the views of Posiva.
  • Camarena‐Gómez, María Teresa; Ruiz‐González, Clara; Piiparinen, Jonna; Lipsewers, Tobias; Sobrino, Cristina; Logares, Ramiro; Spilling, Kristian (American Society of Limnology and Oceanography, 2021)
    Limnology and Oceanography 66: 1, 255-271
    In parts of the Baltic Sea, the phytoplankton spring bloom communities, commonly dominated by diatoms, are shifting toward the co-occurrence of diatoms and dinoflagellates. Although phytoplankton are known to shape the composition and function of associated bacterioplankton communities, the potential bacterial responses to such a decrease of diatoms are unknown. Here we explored the changes in bacterial communities and heterotrophic production during the spring bloom in four consecutive spring blooms across several sub-basins of the Baltic Sea and related them to changes in environmental variables and in phytoplankton community structure. The taxonomic structure of bacterioplankton assemblages was partially explained by salinity and temperature but also linked to the phytoplankton community. Higher carbon biomass of the diatoms Achnanthes taeniata, Skeletonema marinoi, Thalassiosira levanderi, and Chaetoceros spp. was associated with more diverse bacterial communities dominated by copiotrophic bacteria (Flavobacteriia, Gammaproteobacteria, and Betaproteobacteria) and higher bacterial production. During dinoflagellate dominance, bacterial production was low and bacterial communities were dominated by Alphaproteobacteria, mainly SAR11. Our results suggest that increases in dinoflagellate abundance during the spring bloom will largely affect the structuring and functioning of the associated bacterial communities. This could decrease pelagic remineralization of organic matter and possibly affect the bacterial grazers communities.
  • Mammola, Stefano; Piano, Elena; Cardoso, Pedro; Vernon, Philippe; Dominguez-Villar, David; Culver, David C.; Pipan, Tanja; Isaia, Marco (2019)
    Scientists of different disciplines have recognized the valuable role of terrestrial caves as ideal natural laboratories in which to study multiple eco-evolutionary processes, from genes to ecosystems. Because caves and other subterranean habitats are semi-closed systems characterized by a remarkable thermal stability, they should also represent insightful systems for understanding the effects of climate change on biodiversity in situ. Whilst a number of recent advances have demonstrated how promising this fast-moving field of research could be, a lack of synthesis is possibly holding back the adoption of caves as standard models for the study of the recent climatic alteration. By linking literature focusing on physics, geology, biology and ecology, we illustrate the rationale supporting the use of subterranean habitats as laboratories for studies of global change biology. We initially discuss the direct relationship between external and internal temperature, the stability of the subterranean climate and the dynamics of its alteration in an anthropogenic climate change perspective. Owing to their evolution in a stable environment, subterranean species are expected to exhibit low tolerance to climatic perturbations and could theoretically cope with such changes only by shifting their distributional range or by adapting to the new environmental conditions. However, they should have more obstacles to overcome than surface species in such shifts, and therefore could be more prone to local extinction. In the face of rapid climate change, subterranean habitats can be seen as refugia for some surface species, but at the same time they may turn into dead-end traps for some of their current obligate inhabitants. Together with other species living in confined habitats, we argue that subterranean species are particularly sensitive to climate change, and we stress the urgent need for future research, monitoring programs and conservation measures.
  • Yi, Chuixiang; Ricciuto, Daniel; Li, Runze; Wolbeck, John; Xu, Xiyan; Nilsson, Mats; Aires, Luis; Albertson, John D.; Ammann, Christof; Arain, M. Altaf; de Araujo, Alessandro C.; Aubinet, Marc; Aurela, Mika; Barcza, Zoltan; Barr, Alan; Berbigier, Paul; Beringer, Jason; Bernhofer, Christian; Black, Andrew T.; Bolstad, Paul V.; Bosveld, Fred C.; Broadmeadow, Mark S. J.; Buchmann, Nina; Burns, Sean P.; Cellier, Pierre; Chen, Jiquan; Ciais, Philippe; Clement, Robert; Cook, Bruce D.; Curtis, Peter S.; Dail, D. Bryan; Dellwik, Ebba; Delpierre, Nicolas; Desai, Ankur R.; Dore, Sabina; Dragoni, Danilo; Drake, Bert G.; Dufrene, Eric; Dunn, Allison; Elbers, Jan; Eugster, Werner; Falk, Matthias; Feigenwinter, Christian; Flanagan, Lawrence B.; Foken, Thomas; Frank, John; Fuhrer, Juerg; Gianelle, Damiano; Goldstein, Allen; Goulden, Mike; Granier, Andre; Gruenwald, Thomas; Gu, Lianhong; Guo, Haiqiang; Hammerle, Albin; Han, Shijie; Hanan, Niall P.; Haszpra, Laszlo; Heinesch, Bernard; Helfter, Carole; Hendriks, Dimmie; Hutley, Lindsay B.; Ibrom, Andreas; Jacobs, Cor; Johansson, Torbjoern; Jongen, Marjan; Katul, Gabriel; Kiely, Gerard; Klumpp, Katja; Knohl, Alexander; Kolb, Thomas; Kutsch, Werner L.; Lafleur, Peter; Laurila, Tuomas; Leuning, Ray; Lindroth, Anders; Liu, Heping; Loubet, Benjamin; Manca, Giovanni; Marek, Michal; Margolis, Hank A.; Martin, Timothy A.; Massman, William J.; Matamala, Roser; Matteucci, Giorgio; McCaughey, Harry; Merbold, Lutz; Meyers, Tilden; Migliavacca, Mirco; Miglietta, Franco; Misson, Laurent; Moelder, Meelis; Moncrieff, John; Monson, Russell K.; Montagnani, Leonardo; Montes-Helu, Mario; Moors, Eddy; Moureaux, Christine; Mukelabai, Mukufute M.; Munger, J. William; Myklebust, May; Nagy, Zoltan; Noormets, Asko; Oechel, Walter; Oren, Ram; Pallardy, Stephen G.; Kyaw, Tha Paw U.; Pereira, Joao S.; Pilegaard, Kim; Pinter, Krisztina; Pio, Casimiro; Pita, Gabriel; Powell, Thomas L.; Rambal, Serge; Randerson, James T.; von Randow, Celso; Rebmann, Corinna; Rinne, Janne; Rossi, Federica; Roulet, Nigel; Ryel, Ronald J.; Sagerfors, Jorgen; Saigusa, Nobuko; Sanz, Maria Jose; Mugnozza, Giuseppe-Scarascia; Schmid, Hans Peter; Seufert, Guenther; Siqueira, Mario; Soussana, Jean-Francois; Starr, Gregory; Sutton, Mark A.; Tenhunen, John; Tuba, Zoltan; Tuovinen, Juha-Pekka; Valentini, Riccardo; Vogel, Christoph S.; Wang, Shaoqiang; Wang, Weiguo; Welp, Lisa R.; Wen, Xuefa; Wharton, Sonia; Wilkinson, Matthew; Williams, Christopher A.; Wohlfahrt, Georg; Yamamoto, Susumu; Yu, Guirui; Zampedri, Roberto; Zhao, Bin; Zhao, Xinquan (2010)
  • Eyres, Alison; Eronen, Jussi T.; Hagen, Oskar; Boehning-Gaese, Katrin; Fritz, Susanne A. (2021)
    Climatic niches describe the climatic conditions in which species can persist. Shifts in climatic niches have been observed to coincide with major climatic change, suggesting that species adapt to new conditions. We test the relationship between rates of climatic niche evolution and paleoclimatic conditions through time for 65 Old-World flycatcher species (Aves: Muscicapidae). We combine niche quantification for all species with dated phylogenies to infer past changes in the rates of niche evolution for temperature and precipitation niches. Paleoclimatic conditions were inferred independently using two datasets: a paleoelevation reconstruction and the mammal fossil record. We find changes in climatic niches through time, but no or weak support for a relationship between niche evolution rates and rates of paleoclimatic change for both temperature and precipitation niche and for both reconstruction methods. In contrast, the inferred relationship between climatic conditions and niche evolution rates depends on paleoclimatic reconstruction method: rates of temperature niche evolution are significantly negatively related to absolute temperatures inferred using the paleoelevation model but not those reconstructed from the fossil record. We suggest that paleoclimatic change might be a weak driver of climatic niche evolution in birds and highlight the need for greater integration of different paleoclimate reconstructions.
  • Pilla, Rachel M.; Williamson, Graig E.; Adamovich, Boris V.; Adrian, Rita; Anneville, Orlane; Chandra, Sudeep; Colom-Montero, William; Devlin, Shawn P.; Dix, Margaret A; Dokulil, Martin T.; Gaiser, Evelyn E.; Girdner, Scott F.; Hambright, David K.; Hamilton, David P.; Havens, Karl; Hessen, Dag O.; Higgins, Scott N.; Huttula, Timo H.; Huuskonen, Hannu; Isles, Peter D. F.; Joehnk, Klaus D.; Jones, Ian D.; Keller, Wendel Bill; Knoll, Lesley B.; Korhonen, Johanna; Kraemer, Benjamin M.; Leavitt, Peter R.; Lepori, Fabio; Luger, Martin S.; Maberly, Stephen C.; Melack, John M.; Melles, Stephanie J.; Müller-Navarra, Dörthe C.; Pierson, Don C.; Pislegina, Helen V.; Plisnier, Pierre-Denis; Richardson, David C.; Rimmer, Alon; Rogora, Michela; Rusak, James A.; Sadro, Steven; Salmaso, Nico; Saros, Jasmine E.; Saulnier-Talbot, Émilie; Schindler, Daniel E.; Schmid, Martin; Shimaraeva, Svetlana V.; Silow, Eugene A.; Sitoki, Lewis M.; Sommaruga, Ruben; Straile, Dietmar; Strock, Kristin E.; Thiery, Wim; Timofeyev, Maxim A.; Verburg, Piet; Vinebrooke, Rolf D.; Weyhenmeyer, Gesa A.; Zadereev, Egor (Rebekah A. Canada, 2020)
    Scientific Reports 10, 1 (2020), 20514
    Globally, lake surface water temperatures have warmed rapidly relative to air temperatures, but changes in deepwater temperatures and vertical thermal structure are still largely unknown. We have compiled the most comprehensive data set to date of long-term (1970–2009) summertime vertical temperature profiles in lakes across the world to examine trends and drivers of whole-lake vertical thermal structure. We found significant increases in surface water temperatures across lakes at an average rate of + 0.37 °C decade−1, comparable to changes reported previously for other lakes, and similarly consistent trends of increasing water column stability (+ 0.08 kg m−3 decade−1). In contrast, however, deepwater temperature trends showed little change on average (+ 0.06 °C decade−1), but had high variability across lakes, with trends in individual lakes ranging from − 0.68 °C decade−1 to + 0.65 °C decade−1. The variability in deepwater temperature trends was not explained by trends in either surface water temperatures or thermal stability within lakes, and only 8.4% was explained by lake thermal region or local lake characteristics in a random forest analysis. These findings suggest that external drivers beyond our tested lake characteristics are important in explaining long-term trends in thermal structure, such as local to regional climate patterns or additional external anthropogenic influences.
  • Mytty, Tuukka (Helsingfors universitet, 2013)
    Does carbon dioxide predict temperature? No it does not, in the time period of 1880-2004 with the carbon dioxide and temperature data used in this thesis. According to the Inter Governmental Panel on Climate Change(IPCC) carbon dioxide is the most important factor in raising the global temperature. Therefore, it is reasonable to assume that carbon dioxide truly predicts temperature. Because this paper uses observational data it has to be kept in mind that no causality interpretation can be made, only predictive inferences. The data is from the years 1880-2004 and consists of carbon dioxide emissions and temperature anomalies, the base period for the anomalies is 1961-1990. The main analysis method is the cointegrated VAR model but also the standard VAR model is used. The variables were tested for possible unit roots and it was found that there were unit roots present. Then the variables were tested for the cointegrating rank and here the analysis divided into three parts. One, with the assumptions that the variables are integrated of order one, a constant as a deterministic term and one cointegrating relation. Two, variables are allowed to be integrated of order two, a linear trend as a deterministic term and one cointegrating relation. Three, based on some weak evidence there was a result that variables weren’t cointegrated and the analysis could be done in differences. In the first the case it the result was that carbon dioxide doesn’t predict temperature but actually temperature predicted carbon dioxide, the second version gave the same result. In the third case neither one of the variables predicted the other one. These results go against the what is considered as the common consensus in the subject matter of climate change.
  • Räisänen, Jouni (2019)
    The effect of atmospheric circulation on temperature variability and trends in Finland in 1979–2018 is studied using a trajectory-based method. On the average 81% of the detrended interannual variance of monthly mean temperatures is explained by the start points of the three-dimensional trajectories, with the best performance in autumn and winter. Atmospheric circulation change is only found to have had a small impact on the observed annual mean temperature trends, but it has considerably modified the trends in individual months. In particular, changes in circulation explain the lack of observed warming in June, the very modest warming in October in southern Finland, and about a half of the very large warming in December. The residual trends obtained by subtracting the circulation-related change from observations are robustly positive in all months of the year, exhibit a smoother seasonal cycle, and agree better with the multi-model mean temperature trends from models in the 5th Coupled Model Intercomparison Project (CMIP5). Nevertheless, some differences between the residual trends and the average CMIP5 trends are also found.
  • Hänninen, Heikki; Pelkonen, Paavo (Suomen metsätieteellinen seura, 1988)
  • Hänninen, Heikki (Suomen metsätieteellinen seura, 1987)
  • Peng, Li Qing; Tang, Min; Liao, Jia Hong; Liang, Shi Yuan; Gan, Li Tao; Hua, Ke Jun; Chen, Yan; Li, Hong; Chen, Wei; Merilä, Juha (2020)
    Organisms living in extreme environments, such as amphibians inhabiting the Tibetan plateau, are faced with a magnitude of potentially strong selection pressures. With an average elevation exceeding 4500 m, the Tibetan plateau is mainly characterized by low temperatures, but little is known about the influence of this factor on the growth, development, and behaviour of amphibian larvae living in this environment. Using a common garden experiment, we studied the influence of temperatures on the early growth and development of tadpoles of the Tibetan brown frog (Rana kukunoris) endemic to the eastern Tibetan plateau. We discovered that temperature had a significant influence on early growth and development of the tadpoles, with those undergoing high-temperature treatment growing and developing faster than their siblings from a low-temperature treatment. However, high-altitude individuals grew faster than low-altitude individuals at low temperatures. while the opposite was true at high temperatures. These results support the temperature adaptation hypothesis, as tadpoles' growth and developmental rates were maximized at the temperatures experienced in their native environments. These results suggest that variation in ambient temperature. combined with evolutionary adaptation to temperature of local environments, is probably one of the most critical environmental factors shaping altitudinal differences in the growth and development of amphibian larvae on the Tibetan plateau.
  • Nieminen, Martta (Helsingfors universitet, 2013)
    The trend of energy policy in European Union as well as in international context has lately been to increase the share of renewable biofuels. The causes for this are global warming, shrinking reserves of fossil fuels and governments' aspiration for energy independence. Microalgae have shown to be a potential source of biofuels. Though cultivation of microalgae has a long history, has production for fuel yet been unprofitable. Production has become more effective as cultivation has shifted from open ponds to controlled photobioreactors but to achieve effective cultivation methods substantially more understanding on the ecophysiology of microalgae is needed. The aim of my thesis was to research the optimal light intensity and temperature of photosynthesis for three microalgae (Chlorella pyrenoidosa, Euglena gracilis and Selenastrum sp.), which are the main parameters limiting the level of photosynthesis in nutrient rich environments such as photobioreactor. The research strains were incubated in eight light intensities (0,15-250 µmol m-2 s-2) and in 5-6 temperatures (10-35 °C). Photosynthetic activity was determined with radiocarbon method which is based on the stoichiometry of photosynthesis. The purpose of radiocarbon method is to estimate how much dissolved carbon dioxide do the algae assimilate when photosynthesizing. In the method the algae are incubated in light and dark bottles where certain amount of radiocarbon (14C) has been added as a tracer. The algae fix 14C in the proportion to available 12C. 14C method has become the most common way to measure the photosynthesis of microalgae. All of the algal strains grew in 10-30 °C but C. pyrenoidosa was the only one which grew also in 35 °C. The data was analyzed by fitting them with two photosynthesis-light intensity relationship models and one photosynthesis-temperature relationship model and as a result values of essential parameters, i.e. optimal light intensity (Iopt) and temperature (Topt) for photosynthesis, could be estimated. The model which gave the best fit was chosen to describe the photosynthesis-light intensity relationship. The optimal light intensity for C. pyrenoidosa ranged between 121–242 µmol m-2 s-2 and optimal temperature was 15 °C. Corresponding values for E. gracilis were 117-161 µmol m-2 s-2 and 24,1 °C, and for Selenastrum sp. 126-175 µmol m-2 s-2 and 16,7 °C. Q10-values were also determined. With all research strains, the level of photosynthesis increased as light intensity and temperature grew until optimal values were reached. The strains tolerated higher light intensities in warmer temperatures but after reaching the optimal temperature, the level of photosynthesis did not increase any more with elevating temperature. Robust algal strains, i.e. strains, that are most adaptable in terms of light intensity and temperature, are the most prominent ones for biofuel production. From these research strains the most adaptable strain in terms of light intensity was C. pyrenoidosa and in terms of temperature Selenastrum sp. C. pyrenoidosa had superior carbon fixation rate in relation to cell size. Therefore it can be concluded that C. pyrenoidosa is the most suitable algal strains for biofuel applications of the strains assessed here.
  • Vasander, Harri; Lindholm, Tapio (Suomen metsätieteellinen seura, 1985)
  • Nygren, Markku (Suomen metsätieteellinen seura, 1987)
    Tests on seeds from a natural stand and from a clone archive, with various photoperiods and temperature regimes, showed that germination was delayed at low temperature (10 degrees C) and in darkness. This effect diminished the later in autumn seeds were collected.
  • Jauhiainen, Jyrki; Page, Susan E.; Vasander, Harri (2016)
    Agricultural and other land uses on ombrotrophic lowland tropical peat swamps typically lead to reduced vegetation biomass and water table drawdown. We review what is known about greenhouse gas (GHG) dynamics in natural and degraded tropical peat systems in south-east Asia, and on this basis consider what can be expected in terms of GHG dynamics under restored conditions. Only limited in situ data are available on the effects of restoration and the consequences for peat carbon (C) dynamics. Hydrological restoration seeks to bring the water table closer to the peat surface and thus re-create near-natural water table conditions, in order to reduce wildfire risk and associated fire impacts on the peat C store, as well as to reduce aerobic peat decomposition rates. However, zero emissions are unlikely to be achieved due to the notable potential for carbon dioxide (CO2) production from anaerobic peat decomposition processes. Increased vegetation cover (ideally woody plants) resulting from restoration will increase shading and reduce peat surface temperatures, and this may in turn reduce aerobic decomposition rates. An increase in litter deposition rate will compensate for C losses by peat decomposition but also increase the supply of labile C, which may prime decomposition, especially in peat enriched with recalcitrant substrates. The response of tropical peatland GHG emissions to peatland restoration will also vary according to previous land use and land use intensity.
  • Hosseinzadeh, Mahboubeh Sadat; Farhadi Qomi, Masood; Naimi, Babak; Roedder, Dennis; Kazemi, Seyed Mandi (2018)
    Species distribution models estimate the relationship between species occurrences and environmental and spatial characteristics. Herein, we used maximum entropy distribution modelling (MaxEnt) for predicting the potential distribution of the Plateau Snake Skink Ophiomorus nuchalis on the Iranian Plateau, using a small number of occurrence records (i.e. 10) and environmental variables derived from remote sensing. The MaxEnt model had a high success rate according to test AUC scores (0.912). A remotely sensed enhanced vegetation index (39.1%), and precipitation of the driest month (15.4%) were the most important environmental variables that explained the geographical distribution of O. nuchalis. Our results are congruent with previous studies suggesting that suitable habitat of O. nuchalis is limited to the central Iranian Plateau, although mountain ranges in western and eastern Iran might be environmentally suitable but not accessible.