NAME AND DESCRIPTION
DATE AND TIME
Sept 28th – 9AM (GMT-5)
979 9160 2664
Venice was hit heavily twice by severe floods during the last two winters. The related physics and air-sea-land interactions are beautiful examples of how we need to consider the whole system to properly understand what is going on. This holds at both small and large scale, with different feed-backs at different scales.
The 29 October 2018 was stronger, with a strong cyclogenesis on the western Mediterranean Sea that led to unusual disastrous conditions to the west of Italy (Genoa, Ligurian Sea) and at the same time to the strong sirocco wind that led to a heavy storm surge in front of Venice. However, “we were spared” the strongest flood in history because of two conditions: 1) the storm surge peak happened at the trough of the astronomical tide, 2) what was going on on the Ligurian Sea led to a strong westerly wind over northern Italy and Venice, locally killing the sirocco wind, but leading to disastrous wind speeds (196 km/h recorded) on the mountains.
Overall conditions were completely reversed on 12 November 2019: “we were hit”. This was a mild sirocco wind storm with a mild storm surge. However, four, singularly independent and
minor, events happened together leading to what was close to be the worst flood in history: 1) storm surge, 2) extended and persistent inverse barometer effect, 3) perfect superposition of surge and astronomical tide, 4) a very small but violent atmospheric minimum independent of the general situation, leading to local above 100 km/h wind.
I will discuss the physics, the probability and the predictability of similar events. There is a diffused claim that these events are connected to climate change. I will also touch on this topic.
DATE AND TIME
Sept 29th – 4PM (GMT-5)
912 9499 3626
Ecosystems are connected to human well-being in a number of complex ways at multiple time and space scales. Marine and coastal ecosystems are among the most valuable in providing these services. The challenge of ecosystem services science (ESS) is understanding and modeling these connections, with a range of purposes including raising awareness and providing information to allow better management of our natural capital assets. In order for ecosystem services (the benefits provided to humans by ecosystems) to occur, natural capital (natural ecosystems and their products that do not require human activity to build or maintain) must be combined with other forms of capital that do require human intervention to build and maintain. These include: built or manufactured capital, human capital (e.g., human labor and knowledge); and social capital (e.g., communities and cultures). Thus ESS is inherently an integrated, transdisciplinary science that is concerned with the way these four forms of capital contribute to human well-being and the synergies and trade-offs among them. The process of valuation of ecosystem services is about quantifying and modeling these synergies and trade-offs to allow better management. It requires a deeper understanding of the interconnections among human psychology and decision processes, ecosystem processes and functions, and economic production and consumption processes at multiple time and space scales. The challenges of ESS are huge and will require a significantly more transdisciplinary approach than our current academic institutions are comfortable with. But the payoffs are also huge. Our future depends on making rapid progress in this area.
DATE AND TIME
Sept 30th – 9AM (GMT-5)
932 5632 1178
50% of the population of the Tropics will live on the ocean coasts in 2030. It has been established that it will suffer severely from the impacts of climate change (CC), and disproportionately relative to its responsibility in the phenomenon. Moreover, the importance of tropical oceans themselves is paramount for the global climate of our planet (due to heat and CO2 stock), for the marine biodiversity and for the existence of animal species that find their reproductive condition only in these warm waters.
Over the centuries to come, the tropical coastal oceans will suffer from increasing effects of at least four stresses forced by the climate change: warming, acidification, deoxygenation, inducing hypoxia, anoxia and extension of Oxygen Minimum Zones. In addition, there is increased chemical pollution due intense exploitation of continental and ocean biotic and mineral resources. We are only beginning to assess and understand these long-term man-induced disturbances.
Quantification of the ongoing and future impacts on tropical coastal productivity, biodiversity, fisheries, coral reefs and climate, requires that the variations in marine environmental parameters be known and therefore measured in real time and over the long term. Sampling strategies for those regions must be designed bearing in mind the large spatial and temporal variability of the atmosphere and sea-water environments, and the logistic constraints imposed by tropical conditions and diversity in human cultures. We claim that part of the solution will come from the development of fixed buoy-platforms equipped with last generation sensors for physics, biogeochemistry and biology. We present, as a case study, the COCAS International network of coastal buoys anchored nowadays on both sides of the Tropical Atlantic together with examples of new knowledge made possible by its new datasets.
DATE AND TIME
Sept 30th – 5PM (GMT-5)
990 5095 9465
The continuing and rapid global decline of coral reefs calls for new approaches to sustain reefs and the millions of people who depend on them. In this talk, I present ongoing work by my research group aimed at rethinking reef conservation along two lines. First is directly confronting key drivers of change. In addition to environmental factors, there are socioeconomic drivers that influence the condition of coral reef ecosystems, though reef governance rarely focus on explicitly managing these. My colleagues and I analysed data from >2500 reef sites worldwide to quantify how key socioeconomic and environmental drivers are related to reef fish biomass, the presence of top predators, and trait diversity. Our global analysis reveals that the most consistent driver of reef fish assemblages is our metric of potential interactions with urban centres (market gravity). These results highlight underutilized policy levers that could help to sustain coral reefs, such as dampening the negative impact of markets. Second, drawing on theory and practice in human health and rural development, we use a positive deviance (bright spots) analysis to systematically identify coral reefs that have substantially higher biomass than expected, given their socioeconomic and environmental conditions. We then do a “deep dive” into one bright spot where I have been working for 16 years and describe some of the challenges and opportunities of the adaptive reef management system they employ.
DATE AND TIME
Oct 1st – 9AM (GMT-5)
927 4150 8024
An overview of the Gill-Oxygen Limitation Theory (GOLT) will be presented, i.e., of a theory seeking to explain a variety of life processes in fish and aquatic invertebrate by the fact that that the surface of their gills (and hence their oxygen supply) cannot, as 2-dimensional objects, keep up with the growth of their 3-dimensional bodies, and thus with their oxygen requirements. Various processes and attributes of fish and invertebrates will be presented which had to date no mechanistic explanation, but which fit within the GOLT, offered as a tool to interpret phenomena that until now were perceived as unrelated. However, the GOLT should also help to address practical problems, such as arise for fish farming when water temperature increases because of global warming.
DATE AND TIME
Oct 2nd – 9AM (GMT-5)
973 1009 7663
Fishes are widely recognized for extraordinary morphological diversity, including forms as different as deep-bodied butterflyfish, elongate eels, flattened batfish, and large-headed scorpionfish. But, we lack a comprehensive understanding of the nature of this diversity – the major axes of body shape variation and the factors that caused its evolution. I present an analysis of fish body shape diversity using a data set of eight linear measurements of body shape made on over 6,100 species of teleosts. The three primary dimensions of fish bodies, their length, depth and width, each represent a major axis of diversification. In a comparison of benthic, demersal and pelagic marine species I show that a benthic lifestyle results in elevated rates of body shape evolution and the highest disparity among these three realms. Mode of locomotion also influences body shape as species that swim by undulating the body are generally more elongated than species that swim with their median or paired fins, which are deeper-bodied. Feeding mode has a large influence on body shape as fishes that feed by biting benthic prey are more deep-bodied and laterally compressed than suction feeders. Finally, I show the surprising result that marine fishes that live at high latitudes, especially in polar regions, have higher rates of body shape evolution than species that live in equatorial regions. While specific responses to ecological and physiological challenges vary considerably across fishes, these analyses show that there are clear trends in how these factors have shaped fish diversification.
DATE AND TIME
Oct 3rd – 9AM (GMT-5)
912 5888 5207
Although most marine species are diploid (and often highly heterozygous), researchers interested in delineating them usually turn a blind eye to heterozygosity as they focus on haploid (e.g., mitochondrial or chloroplastic) markers or retain only one randomly chosen allele of each locus for their downstream analyses. This is tantamount to forcing a round peg into a square hole and yields highly biased biodiversity estimates. By contrast, haplowebs and conspecificity matrices are recently proposed species delimitation methods that embrace intra-individual polymorphism instead of ignoring it: as they use allele sharing to delineate species, they identify hybrids and introgressed individuals in a sensitive and accurate fashion. For marine fishes, the results of these approaches closely match morphology-based expectations, whereas applications to scleractinian corals suggest that actual hybridization occurs far less often than previously thought.