The deep, ultraoligotrophic piedmont lakes of Northern Patagonia (Argentina) are located in pristine and barely impacted areas, along a wide latitudinal range. Several studies have reported moderate to high total mercury (Hg) concentrations and contrasting methylmercury (CH3Hg+) production in different lake compartments. Sources of Hg for western Patagonian terrestrial and aquatic ecosystems are still not clear; while point sources can be ruled out and atmospheric deposition is a plausible source, along with contribution from active volcanic areas of the Andes. In this investigation, we reported a noticeably seasonal, spatial (between lake branches), and vertical (between water column strata) heterogeneity in the total Hg concentrations found in the pelagic zone of Lake Moreno. Sterile water samples taken in a depth profile of the lake showed moderate to high concentrations of CH3Hg+ in autumn with a decreasing trend with depth. Our results indicated that Hg is largely allocated in the plankton fraction between 10–53 μm; which dominated within the euphotic (epilimnetic) zone of the lake due to the high densities attained by two species of the dinoflagellate Gymnodinium. The 53–200 μm planktonic size fraction (comprising rotifers, ciliates and immature stages of crustaceans) and the 200 μm fraction (calanoid copepods and cladocerans) were found to bear strikingly lower total Hg concentrations, suggesting that the magnification of Hg at the planktonic consumer level is negligible. 相似文献
Environmental and Ecological Statistics - Detection heterogeneity is inherent to ecological data, arising from factors such as varied terrain or weather conditions, inconsistent sampling effort, or... 相似文献
Solid-phase microextraction (SPME) is an effective technique for studying frog volatile secretions. Its primary advantage is in its application to sampling live animals. the ability to sample an organism over an extended period allows changes in an individual's chemical signature to be determined. the presence of eucalyptol in the skin secretion of Ewing's tree frog, Litoria ewingi, was used to assess the effectiveness of SPME in sampling frog volatiles. Rapid sample times coupled with the polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibre provided the best signal/noise ratio for the majority of frog volatiles analysed, and importantly resulted in the least amount of stress to the animals involved. 相似文献
Evaluating the outcomes and tracking the trajectory of biodiversity offsets is essential to demonstrating their effectiveness as a mechanism to conciliate development and conservation. We reviewed the literature to determine the principles that should underpin biodiversity offset planning and the criteria for offset evaluation at the project level. According to the literature, the core principles of equivalence, additionality, and permanence are used as criteria to evaluate conservation outcomes of offsets. We applied the criteria to evaluate offsets of a large iron ore mining project in the Atlantic Forest in Brazil. We examined equivalence in terms of the amount of area per biodiversity value affected and fauna and flora similarity, additionality in terms of landscape connectivity, and permanence in terms of guarantees to ensure protection and restoration offsets lasting outcomes. We found an offset ratio (amount of affected area:offset area) of 1:1.8 for forests and 1:2 for grasslands. Ecological equivalence (i.e., similarity between affected and offset areas) was found for forested areas, but not for ferruginous rupestrian grasslands or for fauna. Landscape metrics showed that connectivity improved relative to the preproject situation as a result of locating restoration offsets in the largest and best-connected forest patch. Permanence of offsets was addressed by establishing covenants and management measures, but financial guarantees to cover maintenance costs after mine closure were lacking. Offsets should be equivalent in type and size, provide conservation outcomes that would not be obtained without them (additionality), and be lasting (permanence). To monitor and evaluate offsets, it is necessary to determine how well these 3 principles are applied in the planning, implementation, and maintenance of offsets. Achieving measurable conservation outcomes from offsets is a long-term endeavor that requires sustained management support, and is information intensive. Thus, offsets require ongoing monitoring and evaluation as well as adaptive management. 相似文献
Economic growth and economic energy consumption have received greater attention due to its contribution to global CO2 emissions in recent decades. The literature on CO2 emissions and innovation for regional differences is very scanty as there is not enough study that considered different regions in a single analysis. We adopt a holistic approach by incorporating different regions so as to assess how innovation contributes to emission reduction. The study, therefore, examined the effects of innovation and economic growth on CO2 emissions for 18 developed and developing countries over the period of 1990 to 2016. The study used panel technique capable of dealing with cross-section dependence effects: panel cross-sectional augmented Dickey-Fuller (CADF) unit root to determine the order of integration, Westerlund cointegration tests confirmed that the variables are co-integrated. We employed panel fully modified ordinary least square (FMOLS) and panel dynamic ordinary least square (DOLS) to estimate the long-run relationship. The results show that energy consumption increases CO2 emissions at all panel levels. However, innovation reduces CO2 emissions in G6 while it increases emissions in the MENA and the BRICS countries. Environmental Kuznets curve (EKC) hypothesis is valid for the BRICS. The pollution haven hypothesis (PHH) and pollution halo effect were confirmed at different panel levels. Based on the findings different policy recommendations are proposed.
This paper contains an assessment and standardized comparative analysis of the current water management regimes in four case-studies
in three European river basins: the Hungarian part of the Upper Tisza, the Ukrainian part of the Upper Tisza (also called
Zacarpathian Tisza), Alentejo Region (including the Alqueva Reservoir) in the Lower Guadiana in Portugal, and Rivierenland
in the Netherlands. The analysis comprises several regime elements considered to be important in adaptive and integrated water
management: agency, awareness raising and education, type of governance and cooperation structures, information management
and—exchange, policy development and—implementation, risk management, and finances and cost recovery. This comparative analysis
has an explorative character intended to identify general patterns in adaptive and integrated water management and to determine
its role in coping with the impacts of climate change on floods and droughts. The results show that there is a strong interdependence
of the elements within a water management regime, and as such this interdependence is a stabilizing factor in current management
regimes. For example, this research provides evidence that a lack of joint/participative knowledge is an important obstacle
for cooperation, or vice versa. We argue that there is a two-way relationship between information management and collaboration.
Moreover, this research suggests that bottom-up governance is not a straightforward solution to water management problems
in large-scale, complex, multiple-use systems, such as river basins. Instead, all the regimes being analyzed are in a process
of finding a balance between bottom-up and top–down governance. Finally, this research shows that in a basin where one type
of extreme is dominant—like droughts in the Alentejo (Portugal) and floods in Rivierenland (Netherlands)—the potential impacts
of other extremes are somehow ignored or not perceived with the urgency they might deserve. 相似文献