103 research outputs found
Epilithic community development on artificial reefs deployed along a cross-shelf environmental gradient off Paraná state, southern Brazil
Plataforma para compartilhamento de dados de pesquisa em agricultura de precisão.
Resumo: Este trabalho descreve a experiência de utilização da plataforma GeoNode para o compartilhamento de dados de pesquisa da Rede de Agricultura de Precisão da Embrapa. A plataforma se mostrou uma boa solução, principalmente para o compartilhamento de dados vetoriais. Para imagens com alta resolução espacial, algumas melhorias são necessárias, principalmente com relação à obtenção dos dados por parte dos usuários autorizados.Editores: Paulino Ribeiro Villas-Boas, Maria Alice Martins, Débora Marcondes Bastos Pereira Milori, Ladislau Martin Neto. SIAGRO 2019
A strong CO<sub>2</sub> sink enhanced by eutrophication in a tropical coastal embayment (Guanabara Bay, Rio de Janeiro, Brazil)
In contrast to its small surface area,
the coastal zone plays a disproportionate role in the global carbon cycle.
Carbon production, transformation, emission and burial rates at the
land–ocean interface are significant at the global scale but still poorly
known, especially in tropical regions. Surface water pCO2 and
ancillary parameters were monitored during nine field campaigns between
April 2013 and April 2014 in Guanabara Bay, a tropical eutrophic to
hypertrophic semi-enclosed estuarine embayment surrounded by the city of Rio
de Janeiro, southeast Brazil. Water pCO2 varied between 22 and 3715 ppmv in
the bay, showing spatial, diurnal and seasonal trends that mirrored those of
dissolved oxygen (DO) and chlorophyll a (Chl a). Marked pCO2
undersaturation was prevalent in the shallow, confined and thermally
stratified waters of the upper bay, whereas pCO2 oversaturation was
restricted to sites close to the small river mouths and small sewage
channels, which covered only 10 % of the bay's area. Substantial daily
variations in pCO2 (up to 395 ppmv between dawn and dusk) were also
registered and could be integrated temporally and spatially for the
establishment of net diurnal, seasonal and annual CO2 fluxes. In
contrast to other estuaries worldwide, Guanabara Bay behaved as a net sink of
atmospheric CO2, a property enhanced by the concomitant effects of
strong radiation intensity, thermal stratification, and high availability of
nutrients, which promotes phytoplankton development and net autotrophy. The
calculated CO2 fluxes for Guanabara Bay ranged between −9.6 and
−18.3 mol C m−2 yr−1, of the same order of magnitude as the
organic carbon burial and organic carbon inputs from the watershed. The
positive and high net community production (52.1 mol C m−2 yr−1)
confirms the high carbon production in the bay. This autotrophic metabolism is apparently
enhanced by eutrophication. Our results show that global CO2
budgetary assertions still lack information on tropical, marine-dominated
estuarine systems, which are affected by thermal stratification and
eutrophication and behave specifically with respect to atmospheric CO2
Freely decaying weak turbulence for sea surface gravity waves
We study numerically the generation of power laws in the framework of weak
turbulence theory for surface gravity waves in deep water. Starting from a
random wave field, we let the system evolve numerically according to the
nonlinear Euler equations for gravity waves in infinitely deep water. In
agreement with the theory of Zakharov and Filonenko, we find the formation of a
power spectrum characterized by a power law of the form of .Comment: 4 pages, 3 figure
Spatial Variation of Bacteria in Surface Waters of Paranaguá and Antonina Bays, Paraná, Brazil
Coastal high-frequency radars in the Mediterranean - Part 1: Status of operations and a framework for future development
Due to the semi-enclosed nature of the Mediterranean Sea, natural disasters and anthropogenic activities impose stronger pressures on its coastal ecosystems than in any other sea of the world. With the aim of responding adequately to science priorities and societal challenges, littoral waters must be effectively monitored with high-frequency radar (HFR) systems. This land-based remote sensing technology can provide, in near-real time, fine-resolution maps of the surface circulation over broad coastal areas, along with reliable directional wave and wind information. The main goal of this work is to showcase the current status of the Mediterranean HFR network and the future roadmap for orchestrated actions. Ongoing collaborative efforts and recent progress of this regional alliance are not only described but also connected with other European initiatives and global frameworks, highlighting the advantages of this cost-effective instrument for the multi-parameter monitoring of the sea state. Coordinated endeavors between HFR operators from different multi-disciplinary institutions are mandatory to reach a mature stage at both national and regional levels, striving to do the following: (i) harmonize deployment and maintenance practices; (ii) standardize data, metadata, and quality control procedures; (iii) centralize data management, visualization, and access platforms; and (iv) develop practical applications of societal benefit that can be used for strategic planning and informed decision-making in the Mediterranean marine environment. Such fit-for-purpose applications can serve for search and rescue operations, safe vessel navigation, tracking of marine pollutants, the monitoring of extreme events, the investigation of transport processes, and the connectivity between offshore waters and coastal ecosystems. Finally, future prospects within the Mediterranean framework are discussed along with a wealth of socioeconomic, technical, and scientific challenges to be faced during the implementation of this integrated HFR regional network
Coastal high-frequency radars in the Mediterranean - Part 2: Applications in support of science priorities and societal needs
The Mediterranean Sea is a prominent climate-change hot spot, with many socioeconomically vital coastal areas being the most vulnerable targets for maritime safety, diverse met-ocean hazards and marine pollution. Providing an unprecedented spatial and temporal resolution at wide coastal areas, high-frequency radars (HFRs) have been steadily gaining recognition as an effective land-based remote sensing technology for continuous monitoring of the surface circulation, increasingly waves and occasionally winds. HFR measurements have boosted the thorough scientific knowledge of coastal processes, also fostering a broad range of applications, which has promoted their integration in coastal ocean observing systems worldwide, with more than half of the European sites located in the Mediterranean coastal areas. In this work, we present a review of existing HFR data multidisciplinary science-based applications in the Mediterranean Sea, primarily focused on meeting end-user and science-driven requirements, addressing regional challenges in three main topics: (i) maritime safety, (ii) extreme hazards and (iii) environmental transport process. Additionally, the HFR observing and monitoring regional capabilities in the Mediterranean coastal areas required to underpin the underlying science and the further development of applications are also analyzed. The outcome of this assessment has allowed us to provide a set of recommendations for future improvement prospects to maximize the contribution to extending science-based HFR products into societally relevant downstream services to support blue growth in the Mediterranean coastal areas, helping to meet the UN's Decade of Ocean Science for Sustainable Development and the EU's Green Deal goals
Biology of Chirocentrodon bleekerianus (Poey, 1867) (Clupeiformes: Pristigasteridae) in a continental shelf region of southern Brazil
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