Efeitos de eventos climáticos extremos e mudança climática na produção agrícola das regiões do Baixo e Submédio da bacia hidrográfica do Rio São Francisco

Este estudo busca investigar os efeitos de eventos climáticos extremos e, por consequência, a influência da mudança climática, sobre o valor da produção agrícola nas regiões do submédio e baixo da Bacia Hidrográfica do Rio São Francisco no Brasil. Para tal, utiliza as análises de cluster e fatorial, combinada com regressões de efeito fixo. Estes métodos permitem levar em conta a interação entre a produção agrícola, a intensidade tecnológica no cultivo, e a diversidade do ecossistema na mensuração do impacto dos eventos climáticos. Os resultados mostram que a temperatura e a precipitação extrema influenciam no valor total da produção agrícola e, ainda, que a tecnologia é necessária, mas não suficiente para combater estas influências. Por fim, a divisão por intensidade tecnológica permite destacar o cunho social dos eventos climáticos. Destaca-se, portanto, necessidade da adoção de melhores estratégias adaptativas que atentem às questões sociais na região.Este estudio busca investigar los efectos de los eventos climáticos extremos y, en consecuencia, la influencia del cambio climático, en el valor de la producción agrícola en las regiones submedia y baja de la Bacia Hidrográfica del Río São Francisco en Brasil. Para ello, utiliza análisis de cluster y factorial, combinados con regresiones de efectos fijos. Estos métodos permiten tener en cuenta la interacción entre la producción agrícola, la intensidad tecnológica en el cultivo y la diversidad de los ecosistemas en la medición del impacto de los eventos climáticos. Los resultados muestran que la temperatura y la precipitación extrema influyen en el valor total de la producción agrícola y que la tecnología es necesaria, pero no suficiente, para combatir estas influencias. Finalmente, la división por intensidad tecnológica permite resaltar el carácter social de los eventos climáticos. Por lo tanto, existe la necesidad de adoptar mejores estrategias de adaptación que aborden los problemas sociales en la región.This study seeks to investigate the effects of extreme weather events, and, consequently, the influence of climate change, on the value of agricultural production in the sub-middle and lower regions of the São Francisco River Basin in Brazil. For this, it uses cluster and factorial analysis, combined with fixed effects regressions. These methods allow considering the interaction between agricultural production, technological intensity in cultivation, and the diversity of the ecosystem in measuring the impact of climatic events. The results show that temperature and extreme precipitations influence the total value of agricultural production, and that technology is necessary, but not sufficient to combat these influences. Finally, the division by technological intensity allows highlighting the social nature of climatic events. Therefore, there is a need to adopt better adaptive strategies that address social issues in the region.Cette étude vise à étudier les effets des événements météorologiques extrêmes et, par conséquent, l'influence du changement climatique, sur la valeur de la production agricole dans les régions submoyennes et inférieures du bassin du fleuve São Francisco au Brésil. À cette fin, il utilise une analyse par grappes et factorielle, combinée à des régressions à effets fixes. Ces méthodes permettent de prendre en compte l'interaction entre la production agricole, l'intensité technologique des cultures et la diversité des écosystèmes pour mesurer l'impact des événements climatiques. Les résultats montrent que la température et les précipitations extrêmes influencent la valeur totale de la production agricole et que la technologie est nécessaire, mais pas suffisante, pour combattre ces influences. Enfin, le découpage par intensité technologique permet de mettre en évidence le caractère social des événements climatiques. Par conséquent, il est nécessaire d'adopter de meilleures stratégies d'adaptation qui répondent aux problèmes sociaux de la région

Vegetated coastal ecosystems in the Southwestern Atlantic Ocean are an unexploited opportunity for climate change mitigation

Vegetated coastal ecosystems (mangroves, seagrasses, and saltmarshes, often called Blue Carbon ecosystems) store large carbon stocks. However, their regional carbon inventories, sequestration rates, and potential as natural climate change mitigation strategies are poorly constrained. Here, we systematically review organic carbon storage and accumulation rates in vegetated coastal ecosystems across the Central and Southwestern Atlantic, extending from Guyana (08.28°N) to Argentina (55.14°S). We estimate that 0.4 Pg organic carbon is stored in the region, which is approximately 2-5% of global carbon stores in coastal vegetated systems, and that they accumulate 0.5 to 3.9 Tg carbon annually. By ecosystem type, mangroves have the largest areal extent and contribute 70-80% of annual organic carbon accumulation, with Brazil hosting roughly 95% of mangrove stocks. Our findings suggest that organic carbon accumulation in the region is equivalent to 0.7 to 13% of global rates in vegetated coastal ecosystems, indicating the importance of conserving these ecosystems as a nature-based approach for mitigating and adapting to climate change

The Ocean and Cryosphere in a Changing Climate in Latin America: Knowledge Gaps and the Urgency to Translate Science Into Action

Climate Change hazards to social-ecological systems are well-documented and the time to act is now. The IPCC-SROCC used the best available scientific knowledge to identify paths for effective adaptation and mitigation of climate change impacts on the ocean and cryosphere. Despite all the evidence highlighted by SROCC and the key role of the ocean and cryosphere for climate change at all levels, Latin America (LA) faces challenges to take effective action mostly due to socio-economic vulnerability, political instability and overall technical capacities. Countries have adopted diverse actions as the information needed by policy makers has been made available, not necessarily in accessible and inclusive ways. Regional imbalance in economic development, technological level, capacity development, societal involvement, and governmental oversight have contributed to skewed geographical and technological gaps of knowledge on key ecosystems and specific areas preventing effective climate actions/solutions. We analyze the Nationally Determined Contributions (NDCs) from the region as proxies to the incorporation of IPCC recommendations. The gaps and opportunities for the uptake of ocean and climate science to political decision making is discussed as five key aspects: (i) climate assessment information and regional policies, (ii) knowledge production, (iii) knowledge accessibility, (iv) knowledge impact to policy, and (v) long term monitoring for decision making. We advocate that the uptake of SROCC findings in LA policies can be enhanced by: (a) embracing local realities and incorporating local, traditional and indigenous knowledge; (b) empowering locals to convey local knowledge to global assessments and adapt findings to local realities; (c) enhancing regional research capabilities; and (d) securing long-term sustainable ocean observations. Local and regional participation in knowledge production and provision enhances communication pathways, climate literacy and engagement which are key for effective action to be reflected in governance. Currently, the lack of accessible and inclusive information at the local level hampers the overall understanding, integration and engagement of the society to mitigate climate effects, perpetuates regional heterogeneity and threatens the efforts to reverse the course of climate change in LA. Local researchers should be empowered, encouraged, rewarded and better included in global climate-ocean scientific assessments.Fil: Muelbert, Mônica M. C.. Universidade Federal de Sao Paulo; Brasil. Universidade Federal do Rio Grande; BrasilFil: Copertino, Margareth. Universidade Federal do Rio Grande; Brasil. Rede Brasileira de Pesquisas sobre Mudanças Climáticas Globais; BrasilFil: Cotrim da Cunha, Leticia. Rede Brasileira de Pesquisas sobre Mudanças Climáticas Globais; Brasil. Universidade do Estado de Rio do Janeiro; BrasilFil: Lewis, Mirtha Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; ArgentinaFil: Polejack, Andrei. World Maritime University; Suecia. Ministério de Ciência, Tecnologia e Inovações; BrasilFil: Peña Puch, Angelina del Carmen. Universidad Autónoma de Campeche; MéxicoFil: Rivera Arriaga, Evelia. Universidad Autónoma de Campeche; Méxic

Bridging soil biogeochemistry and microbial communities (archaea and bacteria) in tropical seagrass meadows

IntroductionSeagrass meadows are among the most valuable ecosystems, providing numerous ecosystem services and functions. Despite its importance, there is a lack of knowledge about soil’s biogeochemical process variability, which can control microbiological communities. Thus, this study aimed to evaluate whether seagrass meadows in different geo-environments exhibit varying Fe and sulfate reduction intensities, shaping distinct archaea and bacteria communities.MethodsSoil samples were collected in seagrass meadows under contrasting climatic, geological, vegetational and hydrological settings along the Brazilian coast (e.g., Semiarid Coast - SC, Southeastern Granitic Coast – GC, and Southern Quaternary Coast - QC). The soils were characterized by particle size, pH, redox potential (Eh), total organic C and total N content, acid-volatile sulfides (AVS), and simultaneously extracted Fe. Furthermore, a solid-phase Fe fractionation was performed to characterize the decomposition pathways in these soils, and the shifts in the microbial community along this spatial variation were analyzed using denaturing gradient gel electrophoresis.ResultsThe studied soils presented a sandy texture (values ranging from 74 ± 11.8 to 80.5 ± 6.4%) caused by energetic hydrodynamic conditions. The pH values were circumneutral, while redox conditions presented significant distinction among the studied sites, ranging from anoxic to oxic (values ranging from -63 to +334 mV). The degree of pyritization (DOP) ranged from< 10% to values higher than 80%, highly influenced by rhizospheric oxidation, and higher AVS content was recorded for sites with lower DOP (i.e., GC and QC).DiscussionsThus, biogeochemical processes in the seagrass soils present a wide variation in response to the geo-environmental settings. Plants influence the soil’s geochemical and microbiological communities, retaining fine particles, promoting rhizosphere oxidation, and inducing anoxic conditions controlling the Fe and S forms. Moreover, the same plant species can result in distinct soil conditions and microbial communities due to geoenvironmental settings

Seagrass and submerged aquatic vegetation (VAS) habitats off the Coast of Brazil: state of knowledge, conservation and main threats

Seagrass meadows are among the most threatened ecosystems on earth, raising concerns about the equilibrium of coastal ecosystems and the sustainability of local fisheries. The present review evaluated the current status of the research on seagrasses and submerged aquatic vegetation (SAV) habitats off the coast of Brazil in terms of plant responses to environmental conditions, changes in distribution and abundance, and the possible role of climate change and variability. Despite an increase in the number of studies, the communication of the results is still relatively limited and is mainly addressed to a national or regional public; thus, South American seagrasses are rarely included or cited in global reviews and models. The scarcity of large-scale and long-term studies allowing the detection of changes in the structure, abundance and composition of seagrass habitats and associated species still hinders the investigation of such communities with respect to the potential effects of climate change. Seagrass meadows and SAV occur all along the Brazilian coast, with species distribution and abundance being strongly influenced by regional oceanography, coastal water masses, river runoff and coastal geomorphology. Based on these geomorphological, hydrological and ecological features, we characterised the distribution of seagrass habitats and abundances within the major coastal compartments. The current conservation status of Brazilian seagrasses and SAV is critical. The unsustainable exploitation and occupation of coastal areas and the multifold anthropogenic footprints left during the last 100 years led to the loss and degradation of shoreline habitats potentially suitable for seagrass occupation. Knowledge of the prevailing patterns and processes governing seagrass structure and functioning along the Brazilian coast is necessary for the global discussion on climate change. Our review is a first and much-needed step toward a more integrated and inclusive approach to understanding the diversity of coastal plant formations along the Southwestern Atlantic coast as well as a regional alert the projected or predicted effects of global changes on the goods and services provided by regional seagrasses and SAV

Production ecology and ecophysiology of turf algal communities on a temperate reef (West Island, South Australia) / Margareth Copertino.

Includes bibliographical references (leaves 235-258).xxi, 274 leaves, [8] leaves of plates : ill. (chiefly col.), map 30 cm.Estimates the primary production and investigates the photosynthetic performance of temperate turfs at West Island, off the coast of South Australia. These communities play a fundamental role in reef ecology, being the main source of food for grazers, both fishes and invertebrates. Turfs also have an important function in benthic algal community dynamics, being the first colonizers on disturbed and bare substratum.Thesis (Ph.D.)--University of Adelaide, Dept. of Environmental Biology, 200