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| 2. |
- Johansson, Markus, et al.
(författare)
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Toxicity of six pesticides to common frog (Rana temporaria) tadpoles
- 2006
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Ingår i: Environmental Toxicology and Chemistry. - 0730-7268 .- 1552-8618. ; 25:12, s. 3164-3170
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Tidskriftsartikel (refereegranskat)abstract
- Amphibian species inhabiting agricultural areas may be exposed to pesticides during their aquatic larval phase. We tested the toxicity of six commonly used pesticides on Rana temporaria spawn and tadpoles. In acute tests, tadpoles were exposed to relatively high concentrations of azoxystrobin, cyanazine, esfenvalerate, MCPA ([4-chloro-2-methylphenoxyl acetic acid), permethrin, and pirimicarb for 72 h. Chronic exposure tests were performed from fertilization to metamorphosis with azoxystrobin, cyanazine, and permethrin at concentrations similar to those found in surface waters in agricultural areas in Sweden. The most lethal pesticides in the acute exposure were azoxystrobin, permethrin, and pirimicarb. Also, negative effects on the growth of the tadpoles were observed with azoxystrobin, cyanazine, and permethrin. The chronic exposure at lower pesticide concentrations did not result in increased mortality or impaired growth. However, we found a positive effect of permethrin on growth and size at metamorphosis. The results suggest that the examined pesticides can inflict strong negative effects at high concentrations but have no or relatively weak effects on R. temporaria spawn or tadpoles at concentrations found in Swedish surface waters.
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| 3. |
- Vaezi, Alireza, et al.
(författare)
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A Late Pleistocene-Holocene multi-proxy record of climate variability in the Jazmurian playa, southeastern Iran
- 2019
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier. - 0031-0182 .- 1872-616X. ; 514, s. 754-767
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Tidskriftsartikel (refereegranskat)abstract
- We present a multi-proxy record from a 5-m long sediment core from the Jazmurian playa in southeastern Iran to provide insights into globally-recognized major climatic events since the Last Glacial Maximum (LGM). In particular, we examined how variability in the Indian Ocean Summer Monsoon (IOSM) and Mid-Latitude Westerlies (MLW) contribute to distinct environmental changes in this arid to hyper-arid region in the interior of West Asia. While interior West Asia showed cold windy conditions during the LGM and post-LGM, southeast Iran experienced quiescent conditions similar to south Asia. The presence of fine-grained sediments, low magnetic susceptibility, and a decrease in aeolian inputs from ca. 21 to 14 cal kyr BP, suggests that effects of both wind and precipitation were minimal during these quiescent conditions. Increased fluvial inputs, coupled with a low abundance of evaporite minerals in Jazmurian sediments, indicated a greater influence of the IOSM between 14 and 13.2 cal kyr BP. In contrast, the Jazmurian playa was dry and dusty between 13.2 and 11.4 cal kyr BP, as reflected by an increase in aeolian sands, and the presence of evaporite minerals. This was followed by a period of strong IOSM activity during the early Holocene, coinciding with higher fluvial input ca. 11.4 cal kyr BP. The early Holocene in southeast Iran was wetter than other analogs in south Asia because of inputs from both IOSM and MWL. Several intense dry periods with sharp increases in aeolian inputs occurred after the early Holocene, due to the southward migration of the Intertropical Convergence Zone. Precipitation sources changed from a monsoon-dominated regime to one influenced mainly by the MLW during the late-Holocene. These results show that palaeoenvironmental changes in the Jazmurian playa, located at the border of IOSM and MLW zones, were primarily governed by global and regional paleoclimatic changes.
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- Veldsman, L-M, et al.
(författare)
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A method to determine the combined effects of climate change (temperature and humidity) and eggshell thickness on water loss from bird eggs
- 2020
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Ingår i: Environmental Geochemistry and Health. - : SPRINGER. - 0269-4042 .- 1573-2983. ; 42:3, s. 781-793
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Tidskriftsartikel (refereegranskat)abstract
- Differences in bird eggshell thicknesses occur due to numerous factors, including thinning due to persistent organic pollutants. Not only does thinning weaken the shell; weaker shells combined with elevated ambient temperature and changes in humidities may result in changes in water loss rates from the egg contents. Therefore, thinner eggshells raise concern of water being lost faster than normal at lower relative humidities, which may affect hatching. To investigate the combined effects, we developed and tested an effective method that measures water loss through different thickness eggshells at controlled temperatures and relative humidities to assist in ascertaining the combined effects of climate change (temperature and humidity) and changes in eggshell thickness on bird reproduction. The fastest rate of loss was at 40% RH at 40 degrees C (0.1 mL/cm(2)/day), and the slowest was at 22 degrees C at 80% RH (0.02 mL/cm(2)/day). Eggshell thickness had a significant effect on water loss at all humidity treatments, except at the highest temperature and humidity treatment (80% RH and 40 degrees C). Temperature explained 40% of the variance, RH explained 20%, and interactions between temperature and humidity explained 15% of the variance (repeated-measures, two-way ANOVA). Generalized linear analyses revealed that both factors temperature and humidity contributed significantly in any two-way combinations. We have laid the ground for a system to test the combined effects of temperature and humidity changes associated with climate change and eggshell thinning associated with pollutants, on water loss across eggshells.
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