IMEDEA Calendar
 
junio 2024
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Abstract



The Southwestern Atlantic Ocean (SWA), is considered one of the most productive areas of the world, with a high abundance of ecologically and economically important fish species. Yet, the biological responses of this complex region to climate variability are still uncertain. Using 24 years of satellite-derived Chl-a data, the SWA was classified into 9 spatially coherent regions based on the temporal variability of Chl-a concentration, as revealed by SOM (Self-Organizing Maps) analysis. These biogeographical regions were the basis of a regional trend analysis in phytoplankton biomass, phenological indices, and environmental forcing variations. A general positive trend in phytoplankton concentration was observed, especially in the highly productive areas of the northern shelf-break, where phytoplankton biomass has increased at a rate of up to 0.42 ± 0.04 mg m −3 per decade. Significant positive trends in sea surface temperature were observed in 4 of the 9 regions (0.08–0.26 °C decade −1) and shoaling of the mixing layer depth in 5 of the 9 regions (−1.50 to −3.36 m decade −1). In addition to the generally positive trend in Chl-a, the most conspicuous change in the phytoplankton temporal patterns in the SWA is a delay in the autumn bloom (between 15 ± 3 and 24 ± 6 days decade −1, depending on the region). The observed variations in phytoplankton phenology could be attributed to climate-induced ocean warming and extended stratification period. The provided results further evidence of the impact of climate change on these highly productive waters.


Jun 7 12:00 12:30
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Seminar “Understanding the network structure of ecosystems to guide conservation action”
Jun 10 10:00 11:30
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Abstract



CyberTracker is a non-profit organization which develops free field data collection software. While Cybertracker software is free of charge, easy to use by a broad range of users due to its simplicity and provides multiple advantages for field data collection in comparison to a manual approach, it is still widely unknown and rarely used. During this talk, I will introduce the software, explain its advantages and applications, the types of hardware available, provide some personal examples of the application during my research and introduce its functioning. Hopefully, the talk will serve for the attendees to understand its potential and consider using this powerful tool that has made my field data collection much easier and efficient and has also improved the quality of the data recorded.


Jun 14 12:00 12:30
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Abstract



Posidonia oceanica meadows have suffered a global regression in the Mediterranean Sea during the last decades. In order to counter this decline, some restoration projects have relied on the use of seedlings as a strategy to accelerate the natural recovery of their meadows and increase genetic diversity. Furthermore, understanding the dynamics and interactions that affect each species and between different organisms are key to enhance restoration success. On this project, we set an experiment in Pollensa Bay (Mallorca, Spain) to study whether P. oceanica seedlings, which had been previously cultured in controlled conditions for three months, improve their survivorship rates at different planting densities (1, 4, 8, 12 and 16 seedlings/0.04 m2). We planted the seedlings in two locations of Pollensa Bay, which presented different substrates: dead matte with marine phanerogams, sand with marine phanerogams and bare sand. Six months after plantation, no density-dependent effect was observed in any of the clumps anywhere. However, an interspecific facilitation effect was noticed for the seedlings planted in sand with other marine phanerogams, as they displayed a 39.27% ± 34.56 average survivorship rate, compared to 0% survivorship on this same substrate without any other seagrass around. Moreover, dead matte remained as the best substrate for restoration purposes, with an average survivorship rate of 57.07% ± 29.92. Our results reinforce the relevance of understanding the ecological interactions between seagrass species in order to increase restoration success, as well as the main factors affecting the survivorship of P. oceanica seedlings in the early stages after establishment in the substrate.


Jun 21 12:00 12:30
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Abstract



Saccharomyces cerevisiae is one of the best studied eukaryotic model organisms. It can alternate between haploid and diploid phases, with lack of nutrients favoring a switch to the haploid phase through a mechanism called sporulation. During sporulation, a single diploid cell generates four haploid daughter cells -a tetrad- which are tightly enclosed within a structure called the ascus. Confinement within the ascus is thought to enforce mating between products of the same meiotic division, minimizing outcrossing in this stage of the life cycle. Therefore, outbreeding has been commonly considered extremely rare in nature. Recent studies, however, have begun to challenge this view by uncovering a surprising ecological niche for the outbreeding of wild yeast: the guts of wasps. Yeast outbreeding in this environment likely involves an interaction between the physicochemical environment of the gut and the biological response of the cells. Preliminary results indicate that ascus breakage results from the combination of physical stresses and enzymatic digestion factors. Mixing due to movement at the gut-level can then promote the formation of multi-strain aggregates and outbreeding. Understanding the natural mechanisms leading to yeast outbreeding in nature will lead us to a better understanding of the S. cerevisiae evolution and adaptation capability. This project is a part of a HFSP grant entitled “The aphrodisiac gut”, in collaboration with research groups specialized in Chemistry from University of Sydney, in Biology from University of Turin and Mathematics from Boston University.



 

Jun 28 12:00 12:30
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