UNA MIRADA A TRAVÉS DE LAS MACROALGAS: Una lupa sumergida bajo los mares antárticos, recopilando y compartiendo el conocimiento sobre las macroalgas.

Bajo el mar antártico se esconde una vida única adaptada a condiciones extremas de temperatura y luz. Las macroalgas antárticas desempeñan un papel fundamental en la producción de oxígeno y en la absorción de dióxido de carbono de la atmósfera, contribuyendo a regular el clima global. Estas importantes productoras primarias son auténticas ingenieras del ecosistema marino, crean y modifican los hábitats y proveen refugio y protección a una variedad de organismos marinos. Se presentan aquí las diferentes líneas de investigación desarrolladas en Caleta Potter, un ecosistema marino antártico costero seriamente afectado por los fenómenos asociados al cambio global

Different feeding strategies in scavenging amphipods and their implications for colonisation success in times of retreating glaciers.

Background: Scavenger guilds, composed of a variety of species, co-existing in the same habitat, are responsible for biomass transformation throughout the food web. Niche partitioning among them can manifest in different feeding strategies, e.g. during carcass feeding. In the bentho-pelagic realm of the Southern Ocean, scavenging amphipods of the speciose superfamily Lysianassoidea are amongst the ubiquitous taxa and occupy an essential role in decomposition processes. First, we addressed the question whether scavenging lysianassoid amphipods have different feeding strategies during carcass feeding, and if their potential synergistic feeding activities influence carcass decomposition. To this end, we compared the relatively large-sized species Waldeckia obesa with the small-sized species Cheirimedon femoratus, Hippomedon kergueleni, and Orchomenella rotundifrons during carcass feeding (Notothenia spp.). Our approach combines ex situ feeding experiments, behavioural observations, and scanning electron microscopic analyses of mandibles. Secondly, we aimed to detect ecological drivers for succession patterns of scavenging amphipods in Antarctic coastal ecosystems affected by environmental disturbances. In Potter Cove, the climate-driven rapid retreat of the Fourcade Glacier is causing various environmental changes including the provision of new marine habitats to colonise. While in the newly ice-free areas fish records are rare, macroalgae have already colonised hard substrates. Therefore, we carried out feeding assays of the most abundant lysianassoids in Potter Cove C. femoratus and H. kergueleni, to determine their consumption rates (mg food x mg amphipods-1 x day-1) and preferences of macroalgae and fish. Results We detected two functional groups with different feeding strategies among the investigated scavenging amphipods: the 'outside-insider' (openers) and 'inside-outsider' (squeezers). Synergistic effects during carcass feeding was not statistical evident. C. femoratus showed a flexible diet when fish was not available by consuming macroalgae with a consumption about 0.2 day-1 but preferred fish with feedings rates up to 0.8 day-1. Contrary, H. kergueleni rejected macroalgae entirely and consumed fish with consumption rates up to 0.8 day-1. Conclusion This study reveals functional groups in scavenging shallow water amphipods and provides new information on coastal intraguild niche partitioning. Moreover, we conclude that dietary flexibility of scavenging amphipods is a potential ecological driver for succession and colonisation of newly available ice-free Antarctic coastal habitats

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost