Weather, Hydrological and Oceanographic Conditions of the Northern Coast of the Río de la Plata Estuary during ENSO 2009–2010

Climatic, hydrological, and oceanographic conditions were determined during the 2009–2010 El Nino/Southern Oscillation (ENSO) on the north coast of the Río de la Plata (RdlP) estuary. The maximum monthly rainfall was observed in the middle and upper La Plata basin during September 2009 and February 2010 (“El Niño” phase, (EN)). The monthly flow of RdlP showed an increase with rainfall and significant differences between ENSO phases. The wind stress showed fluctuations in both phases, being less intense during EN, during which time maximum flow of RdlP was observed. During the EN phase, increased precipitation contributed to variations in salinity and absence of water column stratification in the north coast of RdlP. This was also associated with variations in Secchi depth, oxygen saturation, and nutrient concentrations. The spatial location of the turbidity front was associated with the flow of the RdlP and wind stress, thus conditioning the physicochemical characteristics of the water column, mainly during EN phase

Sea-level trends along freshwater and seawater mixing in the uruguayan Rio de la Plata estuary and Atlantic Ocean coast

Sea level is rising worldwide with local differences due to global and regional drivers. This article analyses yearly freshwater and sea level trends and fluctuations during the mixing of fresh- and sea-water along the Uruguayan coast of the Rio de la Plata River estuary and the Atlantic coast from 1961 to 2014. The global and regional drivers as well as local co-variables are described, classified in nine discrete classes and inter-correlated. Despite the observed increasing trends, local sea level rises (SLR) are not well correlated with global SLR except at the estuarine-ocean boundary (Punta del Este station). Freshwater inflow, which variability often coincides with Oceanic El Niño-La Niña (ONI-ENSO) events, is the first descriptor of sea level fluctuations and outliers all along the coast, particularly at Punta del Este. Local SLR roughly follows the overall global trend with periods of acceleration and stabilization often coinciding with ENSO event

Challenges to climate change adaptation in coastal small towns:Examples from Ghana, Uruguay, Finland, Denmark, and Alaska

The ability of a coastal settlement to adapt to climate change is largely dependent upon access to a range of resources, which many coastal towns and small cities lack. Coastal small towns of less than 10,000 are therefore at a significant disadvantage compared to larger settlements when it comes to adaptation. One way to begin to overcome this disadvantage is to compare coastal small towns in order to identify efficiencies and support knowledge sharing. In this article we present and analyse five case studies of coastal small towns: Fuvemeh, Ghana; Kiyú, Uruguay; Hanko, Finland; Lemvig, Denmark; and Nome, Alaska, USA. A number of key outcomes and lessons were identified which highlights the need for a formal network of international coastal small towns to encourage and develop knowledge sharing practices going forward. A further lesson is the importance of using a range of indicators in order to establish the regional/national importance of a town. Basing this solely on population size can result in an erroneous interpretation of the significance (and therefore adaptive capacity) of a coastal small town. Finally, despite many barriers to adaptation in coastal small towns, being small offers some potential advantages, such as the possibility of being able to form a community consensus more easily, using 3D visualisations for adaptation planning, and having managed realignment as a realistic management option. It is imperative that climate change resilience in coastal small towns is increased by focussing on overcoming barriers and developing appropriate adaptation approaches by governments, non-governmental organisations, business, and researchers

Climate Risks and Reasons for Concern along the Uruguayan Coast of the Rio de la Plata Estuary

The Uruguayan coast of the Río de la Plata river estuary (RdlP) is 300 km long. It encompasses an inner tidal river and a middle and an outer estuary. The RdlP is a micro-tidal system dominated by river inflow from the Paraná and Uruguay rivers and southern winds with increasingly frequent wind-induced storm surges impacting the coast. The El Niño-Southern Oscillation influences the river inflow, prevailing winds, water/sea level and beach erosion. First, we focus on the IPCC Reasons for Concern (RFC) about the trends of climate risks threatening the Uruguayan coast. The trends and maxima of air temperature, water/sea levels and river inflow in three coastal stations from 1980 to 2019 show temporal changes attributable to climate change and El Niño-Southern Oscillation (ENSO). The occurrence, evolution and Montecarlo simulations of return periods of the yearly river flow and sea level height maxima provide metrics of RFC to categorise the climate risks from past to projected future and the level of risk from undetectable to very high. Then, we summarise some current and expected climate risks and present the current adaptation framework and some expected impacts. The RFC has increased, reaching moderate to high-risk levels

Challenges to climate change adaptation in coastal small towns: examples from Ghana, Uruguay, Finland, Denmark, and Alaska

The ability of a coastal settlement to adapt to climate change is largely dependent upon access to a range of resources, which many coastal towns and small cities lack. Coastal small towns of less than 10,000 are therefore at a significant disadvantage compared to larger settlements when it comes to adaptation. One way to begin to overcome this disadvantage is to compare coastal small towns in order to identify efficiencies and support knowledge sharing. In this article we present and analyse five case studies of coastal small towns: Fuvemeh, Ghana; Kiyú, Uruguay; Hanko, Finland; Lemvig, Denmark; and Nome, Alaska, USA. A number of key outcomes and lessons were identified which highlights the need for a formal network of international coastal small towns to encourage and develop knowledge sharing practices going forward. A further lesson is the importance of using a range of indicators in order to establish the regional/national importance of a town. Basing this solely on population size can result in an erroneous interpretation of the significance (and therefore adaptive capacity) of a coastal small town. Finally, despite many barriers to adaptation in coastal small towns, being small offers some potential advantages, such as the possibility of being able to form a community consensus more easily, using 3D visualisations for adaptation planning, and having managed realignment as a realistic management option. It is imperative that climate change resilience in coastal small towns is increased by focussing on overcoming barriers and developing appropriate adaptation approaches by governments, non-governmental organisations, business, and researchers

Form function of sulcus acusticus of the sagittal otolith in seven Sciaenidae (Acanthuriformes) species using geometric morphometrics (southwestern Atlantic)

15 pages, 12 figures, 1 tableThe morphology of otoliths determines the function they perform, and it is influenced by genetic and environmental factors. Knowing those relationships is necessary to understand the role of hearing in fish. The objectives of this work were: exploring the shape of the sulcus of the sagittal otolith in seven species of Sciaenidae, in relation to sound production, and analyzing whether the shape and size of the sulcus can be used as a phylogenetic character. For this purpose, geometric morphometry analysis was carried out using landmarks data. It was found that there is an influence of size on the shape of the sulcus, and significant differences were found between the shapes of the sulcus (permutational multivariate analysis of variance). Three general shapes of the sulcus were identified (using principal component analysis, canonical variate analysis, and clustering): (1) in species that produce sounds at dominant frequencies 350 Hz, the ostium showed a flattened ovoid shape, and the cauda increased its length; (3) the species that do not produce sounds, did not show any modifications, relative to the form of consensus. Despite finding sister species that presented similar sulcus shapes in the phylogeny, the results did not confirm that this can be used as a phylogenetic character. This work discusses whether the combined effects of phylogenetic legacy and natural functional selection have led to convergent evolution for the sulcus form. The differences presented by the sulcus of species that occupy the same clade, could indicate that there is a displacement of characters. The sagittal otolith and the sensory macula associated with the sulcus acusticus are highly plastic structures that are subject to strong evolutionary pressure in relation to environmental and behavioral factors, resulting in great variability in shapes that can be associated with a specific character. The variation in the shape of the sulcus would allow the analysed species to coexist in the same coastal soundscapes, without losing their particular hearing needs, even in case of overlapping their spatial and temporal distribution areasPrograma de desarrollo de las ciencias basicas (PEDECIBA)With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)Peer reviewe

Temporal feeding habits of the whitemouth croaker Micropogonias furnieri in a shallow coastal lagoon (southwestern Atlantic Ocean, Uruguay)

We analyzed the stomach contents of 2915 individuals of the whitemouth croaker, Micropogonias furnieri, ranging from 15.6 to 42.0 cm total length, collected from a coastal lagoon in Rocha, Uruguay, during 1997–1999. A total of 56% (n = 1646) of individuals were found with content in their stomachs. Six food items were identified and classified as crustaceans (49%), polychaetes (26%), vegetal debris (15%), molluscs, juvenile fishes, and unidentified contents, the latter three representing less than 5% of the total stomach contents. Fishes displayed a higher proportion of stomachs with food between February and August 1998, simultaneous with a low gonadosomatic index and a decrease in water temperature. Crustaceans were the dominant food item from November 1997 to March 1998 and from November to December 1998 (austral summer), whereas polychaetes were predominant from April to October 1998 and from January to February 1999. Availability of polychaetes and their higher frequency of occurrence in the stomachs before the reproductive period could play an important role in the reproduction of the species. Feeding frequency was correlated with length classes. Smaller fishes (<25 cm) preyed on polychaetes and vegetal debris, whereas larger fishes fed mainly on crustaceans and fishes. The temporal feeding habits of M. furnieri in this coastal lagoon showed selective and opportune utilization of prey items according to annual variability in reproductive status and water temperature

Elucidating Spirocerca lupi spread in the Americas by using phylogenetic and phylogeographic analyses

Spirocerca lupi is a parasitic nematode of domestic and wild canids of the world. This nematode induces esophageal spirocercosis and may eventually lead to carcinomas, aortic aneurisms, and death of the animal. Two genotypes of S. lupi have been described based on specimens from Europe, Asia, Africa, and Oceania, but no profound analysis has been conducted with S. lupi from the Americas. To study this, S. lupi specimens isolated from domestic dogs from Mexico, Costa Rica, and the United States, were molecularly characterized using 18S rDNA and cox1 fragments. Bayesian inference (BI) phylogenetic trees, Templeton-Crandall-Sing (TCS) haplotype networks and Principal coordinate analysis on nucleotide distances were constructed for each locus separately. In addition, a phylogeographic study using a fragment of the cox1 gene was used to infer the evolutionary history of the genus. BI cox1 trees grouped S. lupi from the Americas in genotype 1, together with Israeli specimens, and showed a high nucleotide identity with those worms. In the TCS network, American specimens clustered next to Israeli S. lupi. Furthermore, the 18S rDNA gene fragment separated Costa Rican worms from African, Asian, and European specimens and other species of the family Spiruridae. Interestingly, phylogeographic analysis suggested that the origin of S. vulpis was in Europe, and it later diverged into S. lupi that spread first to Africa, then to Asia and finally to the Americas. Therefore, we suggest that the worms from the American continent might have originated from Asia by dispersion of infected intermediate, paratenic or definitive hosts.Universidad de Costa Rica/[803-C2-064]/UCR/Costa RicaUCR::Vicerrectoría de Docencia::Salud::Facultad de MicrobiologíaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Enfermedades Tropicales (CIET