Percorrer por autor "Turra, Alexander"
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- Full stomachs at empty tides: tidal cycle affects feeding activity and diet of the sandy beach gastropod Olivella minutaPublication . Checon, Helio H.; Silva, Mariana Oliveira; Corte, Guilherme N.; Yokoyama, Leonardo Q.; Teodosio, Maria; Turra, AlexanderOlivella minuta is an abundant neogastropod on sandy beaches from Texas (USA) to southern Brazil. This study aimed to characterize and compare the feeding activity and diet of a Brazilian population of O. minuta in different tidal zones (intertidal and subtidall, and different tidal levels (high and low tides), with three combinations of tidal zone and level being studied (intertidal during low tide, intertidal during high tide and subtidal). The results showed that diet composition was generally similar among tidal conditions, with O. minuta being a generalist, feeding on 45 different food items. Feeding activity, however, was higher in the intertidal during low tide, whereas the richness and diversity of food items were higher in the intertidal during high tide. The higher feeding activity of O. minuta during low tide may be linked to a lower risk of predation; at low tide organisms may be able to feed for a longer time, arid this may be particularly true on beaches with fine sand, where water retention is higher than that on beaches with coarse sand. The higher diversity of food items consumed in the intertidal during high tide is likely related to the increased prevalence of planktonic food during high tide. Our results indicate that tidal zone and level may strongly influence the feeding activity of coastal soft-bottom species and that species may show higher feeding activity during low tide. Given the current loss of intertidal habitats due to anthropogenic activity and climate-change associated factors, our study has important implications, highlighting the importance of intertidal areas for the ecology and conservation of sandy beach species.
- Marine forests forever—A necessary multilateral program for a fair futurePublication . Horta, Paulo; Sissini, Marina N.; Fonseca, Alessandra; Turra, Alexander; Rodrigues, Ana Claudia; Rorig, Leonardo; Bonomi‐Barufi, José; Pagliosa, Paulo; Bastos, Eduardo; Grimaldi, Guido; Dias, Carlos Eduardo Peixoto; Fialho, Fabio; Oliveira, Carlos Yure B.; Frade, Pedro R.; Schubert, Nadine; Silva, João; Assis, Jorge; Rossi, Sergio; Mansilla, Andres; Soares, Marcelo; Gouvêa, Lidiane; Alves-Lima, Cicero; Coelho, Márcio A. G.; Serrao, Ester A.; Anderson, Antonio Batista; Joyeux, Jean‐Christophe; Berchez, Flávio; Otero‐Ferrer, Francisco; Filho, Jorge Luiz Rodrigues; Mies, Miguel; Araujo, Moacyr; Hall‐Spencer, Jason M.Not only advances but also old addictions, setbacks, obstructions and delays are observed during COP16 (on biodiversity), COP29 (on climate change) and G20 in a year full of tragedies resulting from climate change; we need to look in the rearview mirror and plan new paths to be presented and discussed at COP30, in 2025, in the Brazilian Amazon. Worldwide temperature records show that 2023 and 2024 were the warmest in at least the last 2000 years (Esper, Torbenson, and Büntgen 2024). About 90% of the excess heat trapped by greenhouse gases and 30% of human emissions of carbon dioxide are stored in the ocean, shielding the planet from even more rapid changes in the biosphere. The recent acceleration in climate change is a threat not only to terrestrial systems but also to largely neglected marine ecosystems and their socio-biodiversity. Considering the relationship between global warming and biological extinctions (Malanoski et al. 2024), as well as the high vulnerability of marine biodiversity to these global threats (Pinsky et al. 2019), we call for the urgent need to create global and multilateral policies that are based on climate-smart ocean planning and carbon neutrality, focused on climate adaptation and mitigation strategies to protect, restore and foster sustainable management of marine socio-ecological systems (Frazão Santos et al. 2024).
- Night underwater rides: the activity of a sandy beach gastropod is affected by interactive effects of light availability and water levelPublication . Checon, Helio H.; Silva, Mariana; N. Corte, Guilherme; Q. Yokoyama, Leonardo; Teodosio, M A; Turra, AlexanderOlivella minuta is an abundant gastropod and important consumer on beach food webs, whose feeding activity was recently demonstrated to be reduced when submerged. Our study aimed to test the interactive effects of water level and light in the activity of O. minuta. Experiments were conducted in the laboratory simulating four conditions: (1) Light, emerged (LE); (2) Dark, emerged (DE); (3) Light, immersed (LI); and (4) Dark, immersed (DI). Our results showed a significant interaction between water level and light variation. During conditions of light availability, the results corroborated our expectations and individuals were less active when immersed. However, individuals showed the highest activity when immersed during lightless conditions. This enhanced activity on dark immersed periods can be explained by optimization of feeding strategy, to benefit from the input of food resources brought by the tide. This could also be an adaptation to avoid predation by visual predators, which needs to be further evaluated. Our results show that patterns of activity of O. minuta may be susceptible to impacts of light pollution and coastal squeezing, and that the interacting effects of light and water level need to be considered in further studies on the behaviour of beach organisms.
- The Rio Grande Rise: current knowledge and future frontiers for deep-sea science, mineral resources and governancePublication . Jovane, Luigi; Ulsen, Carina; Galante, Douglas; Bernardini, Simone; Bergo, Natascha Menezes; Braga, Elisabete de Santis; Brandini, Frederico P.; Carrion, Ronaldo; Castro, David Lopes de; Constantino, Renata R.; Bin Hassan, Muhammad; Janasi, Valdecir de Assis; Jeck, Izabel King; Junior, Marco Antonio Couto; Lima, Fabiola A.; de Oliveira Júnior, Luciano; Marques, Simone; Massola, Gustavo M.; Mestre, Nelia C. C.; Mohriak, Webster; Monlevade, Eduardo F.; Oliveira, Carina Costa de; Pellizari, Vivian Helena; Portes, Marcelo Cecconi; Praxedes, Adriane G. P.; Rodrigues, Fabio; Rodrigues, Lucas C. V.; González Sanz, Francisco Javier; Silveira, Ilson C. A. da; Soto, Jules M. R.; Souza-Neto, Pedro Walfir; Sumida, Paulo Y. G.; Tagliaro, Gabriel T.; Silva, Solange Teles da; Turra, Alexander; Santos, Roberto Ventura; Yamamoto, Marcio; Mello, Sidney L. M.The Rio Grande Rise (RGR) is the largest oceanic plateau in the South Atlantic and represents a key natural laboratory for understanding oceanic plateau formation, deep-sea circulation, ecosystem functioning, and ferromanganese crust development. This study presents a critical synthesis of current scientific knowledge on the RGR, integrating geological, geophysical, oceanographic, biological, and geochemical evidence published over the last two decades. Geophysical data reveal a complex tectono-magmatic evolution involving Late Cretaceous plume-related volcanism, crustal thickening, rifting, and subsequent subsidence. The structural framework of the plateau is dominated by the Cruzeiro do Sul Rift, which plays a central role in controlling sedimentation, magmatism, and seawater circulation. Oceanographic studies demonstrate that the interaction between the southern branch of the South Equatorial Current and the complex topography of the RGR generates intense internal tides and bottom currents, strongly influencing sediment transport and benthic habitats. Biological investigations indicate that the RGR hosts diverse deep-sea communities, including sponge grounds, cold-water corals, and associated fauna, whose distribution is tightly linked to geomorphology and hydrodynamics. Ferromanganese crusts occurring on the plateau preserve valuable geochemical records of oceanographic and redox conditions, although their spatial distribution, thickness, and metal budgets remain incompletely constrained. Despite major advances, significant knowledge gaps persist regarding crustal structure, sedimentary evolution, ecosystem functioning, and mineral formation processes. This review highlights these uncertainties and outlines research priorities necessary to improve understanding of oceanic plateaus and deep-sea systems in the South Atlantic.