Abstract

Sunlight drives virtually all life on the Earth’s surface, with about 50% of primary productivity occurring in marine systems. Yet, this traditional view of phototrophy changed radically with the discovery of marine bacterial rhodopsins (i.e., proteorhodopsins; PR), over twenty years ago. PRs are simple light-driven proton pumps present in over 80% of surface bacterioplankton, which allow them to transform light into biochemical energy.

Combining culture-based physiology studies with (meta)-genomics, (meta)-transcriptomics, and environmental quantifications we are just starting to understand the role that PR-based photoheterotrophy plays in the ocean. In this presentation, I will discuss the knowns and unknowns of PR-phototrophy and what we are starting to learn from looking at its natural distributions in different oceanographic basins, ranging from extreme ultraoligotrophic regions to high productivity environments

Abstract

The ability of marine bacteria to direct their movement in response to chemical gradients influences inter-species interactions, nutrient turnover, and ecosystem productivity. While natural chemical hotspots produce gradients comprised of hundreds to thousands of different chemical compounds, we do not know how this chemical diversity affects the chemotactic responses of bacteria. I will present results from two studies that reveal some unexpected responses when bacteria are exposed to complex chemical mixtures. Using in situ and laboratory-based assays, we show that marine bacteria are strongly attracted to the abundant algal polysaccharide laminarin, but chemotaxis towards this large molecule is enhanced by dimethylsulfoniopropionate (DMSP), another ubiquitous algal-derived metabolite. Our results indicate that DMSP acts as a methyl donor for marine bacteria, increasing their gradient detection capacity and facilitating their access to polysaccharide patches. Using a novel chemotaxis choice assay, we then directly expose a model marine bacterium to four potent chemoattractants simultaneously (i.e., one monosaccharide and three amino acids). Although the bacterium is strongly chemotactic to each of these molecules in isolation, when these four molecules are provided simultaneously, the cells exhibit a striking response by swimming towards only one of them. These results start shedding light on the synergistic effects (e.g., laminarin and DMSP) and sharp chemical preferences modulating the behaviours of bacteria.

INTERNATIONAL VISITING SCHOLAR PROGRAMME (IVSP)

Abstract

Seagrass meadows and the services they provide are declining worldwide as a result of human perturbations. Along the Swedish W coast, almost 60% of the seagrass has been lost since the 1980's, representing a loss of approximately 190 km2 of seagrass. The seagrass Zostera marina, L. (eelgrass) is the dominant macrophyte on soft bottoms along the Swedish coast. The decrease in seagrass worldwide has lead to many restoration programs but their success rate is very low due to the regime shift and feedback mechanisms that also prevent natural recovery.

This presentation aims to provide a review on the restoration successes and challenges on eelgrass in Sweden. For example, positive feedbacks generated by water turbidity due to sediment resuspension, drifting macroalga covering eelgrass transplants and the presence of eelgrass predators such as shore crabs have been identified as causes affecting restoration success. To overcome these issues, restoration techniques using sand-capping have shown to be successful to reintroduce eelgrass in areas where it was lost. An interdisciplinary approach using field and laboratory experiments linked with hydrodynamical modeling showed to be key to understand the complex coastal ecological dynamics.

In addition, new methods to monitor coastal habitats such as seagrass meadows and marine mammals (dugongs and seals) using aerial drones and machine learning will be presented. These new technologies can contribute to faster data collection and data analysis for ecological studies and to provide relevant information to coastal managers and decision makers working on ecological conservation.

Bio

Eduardo Infantes is a researcher at the University of Gothenburg in Sweden, where he leads the Seagrass Ecology Lab research group  based at Kristineberg marine station. With a focus on seagrass ecology over the last 18 years, his main interests are in 1) studying interactions between fluid dynamics and marine vegetation through field data, mesocosm experiments and flume studies, 2) restoration of coastal habitat using seagrass within the interdisciplinary ZORRO group, and 3) monitoring of seagrass beds and marine mammals (e.g. harbor seals, manatees, and dugongs) using drones and AI. With an interdisciplinary profile, he collaborates in research and management, contributing to environmental policies in coastal restoration and monitoring.

Abstract

Establishing root systems in rhizome fragments of Posidonia oceanica presents a significant challenge for its restoration. Rhizome fragments of this slow-growing seagrass require robust rooting for successful anchorage and nutrient absorption from the environment. Controlled experiments have demonstrated that the use of plant growth regulators, such as the auxins α-naphthaleneacetic acid (NAA) and indole-3-butyric acid (IBA), stimulates rooting in P. oceanica cuttings. However, this effect has not been tested in a marine environment. In this study, rhizome fragments were exposed to varying concentrations of NAA and IBA for 24 hours before transplanting into a dead matte area in the Bay of Pollensa (Mallorca, Spain). After one year, all fragments survived; however, contrary to expectations, no significant differences emerged in the growth and biomass of roots, rhizomes (orthotropic and plagiotropic), and leaves between treated and untreated fragments. This implies that applying auxins to P. oceanica rhizome fragments may not offer an advantage when rooting transplants in the marine environment. Future studies should explore how other environmental conditions can influence rooting and interactions with auxin effects over time.

Abstract

The animal gut hosts diverse bacterial communities that can affect the individual’s behavior, physiology, and metabolism. However, the relationship between an individual’s microbiome and its social behavior in the wild is poorly understood. We tested the hypothesis that social behavior in the wild is correlated with the gut microbiome composition in a marine fish (Xyrichtys novacula). Relying on high-resolution acoustic telemetry, we first obtained a high-quality positioning data set from 232 individuals (153 females and 79 males). From these data, we computed the associations between paired individuals and found a harem-like social structure. Territories were formed by one male and several females, and males displayed agonistic behaviors towards their neighbors to defend territories. Subsequently, a sample of the social network was captured, and the diversity of the gut microbiome was quantified using operational phylogenetic units (OPUs) based on the analysis of 16S rRNA gene amplicons using Illumina high throughput sequencing. The social network properties were strongly correlated to the gut microbiome. Individual microbiome samples of fish from the same harem (including from different sex) were more similar to each other, while differences to other harems were strong. The use of similar local microhabitats, including food resources, as well as local social contact can both provide key transmission pathways for gut symbionts that shape gut microbiota, structuring the microbiome along social networks in aquatic animals. This work is among the first to show a relationship between social structure and the microbiome in a fish species in the wild. Further work is needed to reveal cause-and-effect relationships into whether the social network shapes the microbiome or the microbiome and the resulting metabolites shape certain behaviors that in turn create the network structure.

Abstract

Seed predation and dispersal play key roles in the regeneration of tropical trees. Seeds may escape pre-dispersal predation when ingested with the fruit pulp and moved away from the parent trees by frugivores. Frugivore species may influence dispersal quality differently even when feeding on the same fruit species. In southern Mexico, we investigated if seed traits (i.e., length, width, and mass) and germination success differed among seeds ingested by howler monkeys (Alouatta pigra), spider monkeys (Ateles geoffroyi), and non-ingested seeds. For this, we recorded the germination rate and percentage of seeds from five tropical tree species, including the following: Ampelocera hottlei , Brosimum lactescens , Dialium guianense, Spondias mombin and Spondias radlkoferi. Furthermore, only for D. guianense we determined if there was a primate selection towards seeds with no insect damaged. Results showed that traits of seeds ingested by howler monkeys differed from those ingested by spider monkeys and non-ingested seeds; while seeds ingested by spider monkeys were similar to non-ingested seeds. Howlers consumed on average the larger seeds. For all five tree species, germination rate was greatest for seeds ingested by howler monkeys. The proportion of damaged seeds declined significantly from non-ingested seeds (48 %), to seeds in spider monkey feces (29 %), and finally to seeds in howler monkey feces (7 %). Fruit selection by primate species influences dispersal quality differently, even when feeding on the same plant species. Howler monkeys may increase the reproductive success of the studied tree species by selecting larger and predation-free seeds/fruits.

You4Blue - Young Generations for Sustainable Blue Growth es un proyecto Erasmus+ dirigido a estudiantes de secundaria en tres islas mediterráneas de la UE, con el objetivo de aumentar la conciencia sobre los desafíos ambientales y proporcionar herramientas para una vida sostenible. El proyecto fomenta una nueva relación con el medio ambiente, desarrolla competencias en áreas STEAM y TIC, y promueve habilidades blandas como la empatía y el pensamiento crítico.

En el marco de este proyecto, el “Sea Curriculum” promueve la participación de estudiantes locales en experiencias prácticas relacionadas con los ecosistemas y las ciencias marinas. Este componente está coordinado por IMEDEA en colaboración con IES Bendinat, con el objetivo de desarrollar e implementar estas actividades de aprendizaje. Una de las actividades consiste en que los estudiantes elijan una temática de investigación y preparen una presentación, la cual será expuesta en IMEDEA.

Comprender y mitigar la acidificación de los océanos

AUTORES: Gemma Semley-Dyne, Fiona Martina Torres Cruz, Manoela Tsvetanova Manolova, Marc Reynes Garcia, Amelia Moral Blanco, Vlada Stashkevych.

¿Es posible un turismo sostenible en Mallorca?

AUTORES: Marcos Merino Sierra, Amadou Sall, Toni Matias Castell, Daniel Sander Gassner, Diego Bertorelli Carmona

Praderas de Posidonia: ante una nueva extinción?

AUTORES: Fernando Blanes, Hugo Gonzalez, Noelia Navarro, Alicia Catalá, Andrea Thyus, Lily Ron

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.

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.

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.

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.