A partir del año 2015, aumentó considerablemente la demanda y el precio del litio debido a su rol central en la producción de baterías. América Latina posee alrededor del 60% de las reservas de litio a nivel mundial. Los yacimientos se ubican, principalmente, en la puna que comparten Chile, Bolivia, Perú y Argentina. La posibilidad de extraer litio de los salares es promocionada por gobiernos y empresas como una oportunidad irrenunciable. A su vez, la minería de litio es presentada como clave para la solución a la crisis climática, ante la necesidad de disminuir los gases de efecto invernadero y favorecer la transición energética. En oposición, la extracción de litio es considerada por las comunidades locales como perniciosa porque involucra la pérdida de grandes volúmenes de agua, en la medida en que el litio se encuentra disuelto en los salares y de que una gran cantidad de agua dulce es utilizada durante el proceso y por la contaminación química que genera. En este trabajo se abordará la construcción discursiva y argumentativa de la extracción de litio. La hipótesis general es que la extracción de litio se presenta como inevitable en tanto no hay otras alternativas posibles frente a la crisis climática, impidiendo su discusión en términos políticos.
This study examined the development of biofouling assemblages on cage net panels submerged at different depths in a fish farm in the Red Sea. Experimental rafts equipped with Dyneema fibre nets were submerged at depths of 5, 10 and 15 m. Results showed significant variations (P < 0.05) in fouling biomass and the composition of fouling communities among the three depths. The highest biomass accumulation (average: 71.06 g dm−2 month−1) was recorded on panels at 5 m. The fouling community that settled on the net panels included macroalgae, sponges, bryozoans, hydrozoans, mussels and ascidians. Although the results indicated a distinct pattern of successional phases during the growth of the fouling community on the cage net panels, the abundance of dominant fouling organisms varied between depths. At 5 m, ascidians and algae were most abundant, whereas panels at 10 m were primarily colonized by ascidians, bryozoans and hydrozoans. At 15 m, ascidians and bryozoans were dominant. Overall, the findings suggest that fouling abundance decreases at greater depths, with the lowest colonization observed at 15 m. These results provide valuable insights for developing effective biofouling management strategies to mitigate excessive accumulation of dominant fouling organisms in this region.
In response to the surge of urbanization in the modern era, many organisms have undergone various changes, such as the shift of their morphological traits to face the challenges brought by this drastic environmental transformation. Rapid adaptive evolution in the morphology of urban-dwelling organisms has been documented in a broad array of taxa, such as lizards and birds, by comparing urban populations with their nonurban counterparts. However, relevant studies concerning more elusive and secretive organisms that also occur in both natural and urbanized habitats (e.g., snakes), are still lacking. Snakes lack appendages, which are often the trait of interest in other morphological studies, but factors such as head shape play a critical role in snakes, as it determines the prey size of these gape-limited predators. In this study, we apply both linear and geometric morphometric analyses to examine interpopulation morphological differences and sexual dimorphism in a small, semi-fossorial snake, Dekay’s brownsnake (Storeria dekayi). We focus on head shape in six different populations across the rural-urban gradient in New Jersey and New York, USA. We find evidence of increased morphological divergence and decreased sexual dimorphism in populations inhabiting more urbanized areas. Our study suggests the occurrence of an adaptive morphological shift in this common species in the urban environments, and lays the path for further investigation of urban adaptation in snakes and similar secretive species.
This study was conducted to identify changes in insect composition and function before and after the construction of onshore wind farms. We investigated insect fauna, composition, and functional groups in grassland and forest sites at the operational Muchang Wind Farm (MC) in Yeongdeok and Yeongyang, Gyeongsangbuk-do, and the planned Gasan Wind Farm (GS) in Jeongsun, Gangwon-do, Korea. Insects were collected using a sweeping net, pitfall traps, and light traps. A total of 12 orders, 75 families, and 2,497 individuals were collected across the study sites. Among taxonomic groups, the order with the highest species and individual counts was Lepidoptera, with 222 species and 628 individuals (25.0%), followed by Coleoptera, with 81 species and 241 individuals (23.5%). Additionally, based on functional groups such as herbivores, predators, decomposers, etc., the results reveal distinct differences in the proportion of these groups between grasslands created by habitat disturbance at the operational MC site and those at the planned GS site. The findings of this study provide valuable insights into the effects of habitat changes due to onshore wind farm establishment on insect communities.
Seagrass meadows provide important ecosystem services including carbon sequestration, coastal protection from erosion, and sustained biodiversity and fisheries thereby improving the wellbeing and livelihoods of coastal communities. The erosion of millenary deposits of intertwined roots and rhizomes of Posidonia results in the formation of three-dimensional structures named escarpments that constitute a biogenic reef habitat. However, the natural history of seagrass escarpments including their formation processes and their role as habitat for reef fauna and flora remains poorly understood. This research located and characterized Posidonia oceanica escarpments in Menorca (Balearic Islands) and compared structural complexity and fish assemblages among seagrass escarpments, seagrass meadows, rocky substrates and bare sand with emphasis on its role as habitat and shelter for typical rocky fish. Fish abundance and biomass were similar between seagrass escarpments and rocky substrates (P > 0.05), but significantly lower in seagrass meadows (P < 0.001). The large number of caves found along seagrass escarpments provide shelter to fish, including species only associated to rocky substrates. Seagrass meadows form a rather homogenous habitat within their canopy, but the presence of seagrass escarpments enhances habitat heterogeneity and structural complexity along with fish abundance and biomass at the seascape level. This study enhances understanding on the ecological importance of seagrass escarpments.
Science, General. Including nature conservation, geographical distribution
The intermittent ozone (O<sub>3</sub>) exposure of crops to alternating high and low concentrations is common in fields, but its impact on crop production has not been thoroughly investigated. In this study, two widely planted and O<sub>3</sub>-sensitive crops, winter wheat and soybean, were intermittently exposed to elevated O<sub>3</sub> concentrations in open-top chambers. The results showed that the winter wheat and soybean yields significantly decreased with O<sub>3</sub> exposure (AOT40, cumulative hourly O<sub>3</sub> concentration above 40 ppb) (<i>p</i> < 0.001). The relative yield losses were 0.99% per AOT40 for winter wheat and 1.2% per AOT40 for soybean, respectively. The responses of the crop biomasses to elevated O<sub>3</sub> concentrations were lower than that of crop yield. Although the O<sub>3</sub>-induced crop yield and biomass losses under continuous O<sub>3</sub> exposure were greater than those under intermittent O<sub>3</sub> exposure, the differences were not statistically significant. Therefore, we can conclude that the effects of elevated O<sub>3</sub> concentrations on crops are closely related to the exposure dose but not significantly related to the temporal distribution of elevated O<sub>3</sub> concentrations. This study improves our understanding of how crop production responds to intermittent O<sub>3</sub> exposure.
Andrée De Cock, Marie Anne Eurie Forio, Luis Dominguez-Granda
et al.
Increasing anthropogenic activities are affecting water quality and related ecosystem services in river basins worldwide. There is a need to identify and act on synergies between the water-energy-food (WEF) elements and the other Sustainable Development Goals (SDGs) while mediating trade-offs. The Guayas river basin (GRB), one of the major watersheds in Ecuador, is being affected by increasing urbanization, agricultural and industrial activities. In this perspective paper, we indicate the WEF interactions in the GRB linked to the SDGs. A major challenge is the geographical distance between pressures and impacts, for which environmental and agricultural governance are key to support the needed change towards sustainable development. In particular, the realization of measures to reduce the pollutant input in upstream systems will need both legislative and financial means to solve downstream water quality problems. A Bayesian belief network (BBN) framework was developed in order to support sustainable decision making in the GRB. The discussed concepts can be applied to other river basins worldwide since, in many basins, very similar food production challenges need to be addressed.
Abstract Background Horizontal gene transfer (HGT) has been documented in many herbivorous insects, conferring the ability to digest plant material and promoting their remarkable ecological diversification. Previous reports suggest HGT of antibacterial enzymes may have contributed to the insect immune response and limit bacterial growth. Carnivorous insects also display many evolutionary successful lineages, but in contrast to the plant feeders, the potential role of HGTs has been less well-studied. Results Using genomic and transcriptomic data from 38 species of ladybird beetles, we identified a set of bacterial cell wall hydrolase (cwh) genes acquired by this group of beetles. Infection with Bacillus subtilis led to upregulated expression of these ladybird cwh genes, and their recombinantly produced proteins limited bacterial proliferation. Moreover, RNAi-mediated cwh knockdown led to downregulation of other antibacterial genes, indicating a role in antibacterial immune defense. cwh genes are rare in eukaryotes, but have been maintained in all tested Coccinellinae species, suggesting that this putative immune-related HGT event played a role in the evolution of this speciose subfamily of predominant predatory ladybirds. Conclusion Our work demonstrates that, in a manner analogous to HGT-facilitated plant feeding, enhanced immunity through HGT might have played a key role in the prey adaptation and niche expansion that promoted the diversification of carnivorous beetle lineages. We believe that this represents the first example of immune-related HGT in carnivorous insects with an association with a subsequent successful species radiation.
The paper investigates how different field conditions and sample characteristics influence genotyping success in field-collected brown bear scat samples. Genotyping performance of 413 samples collected in a pilot study in southern Slovenia was evaluated, andstatistical modelling was used to control confounding between pre- dictor variables and to quantify their specific effects ongenotyping success. The best predictors of genotyping success were subjectively estimated scat age, sampling month, and contents of ascat. Even when the other confounded variables were controlled for, genotyping success dropped rapidly with the age estimate, from 89% (82-94%) for 0-day scats to 33% (19-52%) for scats estimated to be 5 days old. Sampling month was also an important predictor, and samples collected during the bear hyperphagia period in late summer/autumn performed considerably better (90%,78-96%) than the samples collected in spring / early summer (66%, 57-74%). This effect was stronger for fresh than for older samples. Effects of different food types were also considerable, but less important for practical use. Since noninvasive genetic sampling already became the key method for surveying wild populations of many species, efficiency of studies is becoming increasingly important. Understanding the effect of the month of sampling allows the field season to be timed for maximum genotyping success, while subjective scat age provides a useful metric that indicates a sample’s viability for genotyping, allowing for prioritization of samples and culling of non-viable samples before resources are wasted for their analysis. This provides higher useful data yields per invested resources and may ultimately lead to better study results.
Graham A. Colby, Matti O. Ruuskanen, Kyra A. St.Pierre
et al.
Temperatures in the Arctic are expected to increase dramatically over the next century, and transform high latitude watersheds. However, little is known about how microbial communities and their underlying metabolic processes will be affected by these environmental changes in freshwater sedimentary systems. To address this knowledge gap, we analyzed sediments from Lake Hazen, NU Canada. Here, we exploit the spatial heterogeneity created by varying runoff regimes across the watershed of this uniquely large high-latitude lake to test how a transition from low to high runoff, used as one proxy for climate change, affects the community structure and functional potential of dominant microbes. Based on metagenomic analyses of lake sediments along these spatial gradients, we show that increasing runoff leads to a decrease in taxonomic and functional diversity of sediment microbes. Our findings are likely to apply to other, smaller, glacierized watersheds typical of polar or high latitude ecosystems; we can predict that such changes will have far reaching consequences on these ecosystems by affecting nutrient biogeochemical cycling, the direction and magnitude of which are yet to be determined.
Abstract Among the traits whose relevance for plant invasions has recently been suggested are genome size (the amount of nuclear DNA) and ploidy level. So far, research on the role of genome size in invasiveness has been mostly based on indirect evidence by comparing species with different genome sizes, but how karyological traits influence competition at the intraspecific level remains unknown. We addressed these questions in a common‐garden experiment evaluating the outcome of direct intraspecific competition among 20 populations of Phragmites australis, represented by clones collected in North America and Europe, and differing in their status (native and invasive), genome size (small and large), and ploidy levels (tetraploid, hexaploid, or octoploid). Each clone was planted in competition with one of the others in all possible combinations with three replicates in 45‐L pots. Upon harvest, the identity of 21 shoots sampled per pot was revealed by flow cytometry and DNA analysis. Differences in performance were examined using relative proportions of shoots of each clone, ratios of their aboveground biomass, and relative yield total (RYT). The performance of the clones in competition primarily depended on the clone status (native vs. invasive). Measured in terms of shoot number or aboveground biomass, the strongest signal observed was that North American native clones always lost in competition to the other two groups. In addition, North American native clones were suppressed by European natives to a similar degree as by North American invasives. North American invasive clones had the largest average shoot biomass, but only by a limited, nonsignificant difference due to genome size. There was no effect of ploidy on competition. Since the North American invaders of European origin are able to outcompete the native North American clones, we suggest that their high competitiveness acts as an important driver in the early stages of their invasion.