Medusae and ctenophores from the Bahia Blanca Estuary and neighboring inner shelf (Southwest Atlantic Ocean, Argentina)

An updated checklist of medusae and ctenophores is presented for the first time for the area comprised by the Bahía Blanca Estuary, the adjacent shelf El Rincón and Monte Hermoso beach, on the southwest coast of Buenos Aires province (Argentina). The area is highly productive and provides several ecosystem services including fishing and tourism. Updated information on the biodiversity of medusae and ctenophores species is essential for the study area, given that these species can affect ecosystem services. The list includes 23 hydromedusae, 3 scyphomedusae, and 3 ctenophores. Five hydromedusae (Halitiara formosa, Amphinema dinema, Aequorea forskalea, Clytia lomae and Halopsis ocellata) were firstly observed in this area. Three species of medusae, 2 hydromedusae (Olindias sambaquiensis and Liriope tetraphylla) and 1 scyphomedusae (Chrysaora lactea) pose a potential health risk, due to their toxicity to humans. Considering the size of the study area, the Bahía Blanca region has a comparatively high species richness of hydromedusae, higher than larger zones previously studied along the temperate SW Atlantic Ocean. The present report provides the baseline knowledge of gelatinous species for the Bahía Blanca region.Fil: Dutto, María Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Genzano, Gabriel Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Schiariti, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Lecanda, Maria Julieta. Museo Municipal de Ciencias Naturales de Monte Hermoso; Argentina. Universidad Nacional del Sur; ArgentinaFil: Hoffmeyer, Monica Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Tecnológica Nacional; ArgentinaFil: Pratolongo, Paula Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

Patterns and Trends in Chlorophyll-a Concentration and Phytoplankton Phenology in the Biogeographical Regions of Southwestern Atlantic

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. Here, using 24 years of satellite-derived Chl-a data, we classified the SWA 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. Our results provided further evidence of the impact of climate change on these highly productive waters.Fil: Delgado, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Geografía y Turismo; ArgentinaFil: Hernández Carrasco, Ismael. Consejo Superior de Investigaciones Científicas. Instituto Mediterráneo de Estudios Avanzados; EspañaFil: Combes, Vincent. Consejo Superior de Investigaciones Científicas. Instituto Mediterráneo de Estudios Avanzados; España. Universitat de Les Illes Balears; EspañaFil: Font Muñoz, Joan. Consejo Superior de Investigaciones Científicas. Instituto Mediterráneo de Estudios Avanzados; EspañaFil: Pratolongo, Paula Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Geografía y Turismo; ArgentinaFil: Basterretxea, Gotzon. Consejo Superior de Investigaciones Científicas. Instituto Mediterráneo de Estudios Avanzados; Españ

Influence of macrobenthos ( Meretrix meretrix Linnaeus ) on erosion‐accretion processes in intertidal flats: A case study from a cultivation zone

The activity of benthic organisms can strongly influence sediment dynamics in anintertidal flat. However, few studies have conducted a quantitative assessment of the effect of benthic organisms on erosion-accretion processes under field conditions. The aim of this study was to quantify the effects of the benthic clam Meretrix meretrix Linnaeus on bed erodibility and sediment erosion- accretion processes in an intertidal flat. Within the cultivation zone atsite A, M. meretrix is present in large numbers (up to 137 individuals/m2). On the other hand, site B is located outside the cultivation zone. At this site, which is only 500 m away from site A alongshore, M. meretrix forms a sparse population with only 3.7 individuals/m2. The results showed that the critical shear stress for erosion, denoted by τce, was 0.22 and 0.32 N/m2 at sites B and A, respectively, and the magnitudes of bed-level change were significantly higher at site A than site B. These results reveal the large effect of M. meretrix on decreasing τce, augmenting the erosion rate when the bed shear stress due to combined currents and waves, denoted by τcw, was higher than τce, and conversely enhancing the accretion rate when τcw < τce. The changes induced in these parameters are likely to have a large impact on model predictions of bed erodibility, sedimentary processes, and morphological evolution. Thus, integrated field measurements of hydrodynamic and bed-level changes, accompanied by simultaneous biological sampling, may help to improve the parameterization of hydro-sedimentary and morphodynamic models for shallow-water environmentsFil: Shi, Benwei. Tongji University; República de China. East China Normal University; República de ChinaFil: Pratolongo, Paula Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Duy, Yongfen. Nanjing Normal University; República de ChinaFil: Li, Jiasheng. Nanjing Normal University; República de ChinaFil: Yang, S.L.. East China Normal University; República de ChinaFil: Wu, Jihua. Fudan Universit. Institute of Biodiversity Science; República de ChinaFil: Xu, Kehui. State University of Louisiana; Estados UnidosFil: Wang, Ya Ping. East China Normal University; República de Chin

Evaluation of modis-aqua and olci chlorophyll-a products in contrasting waters of the southwestern Atlantic ocean

Satellite chlorophyll-a concentration (Chl-a) estimations provide a valuable tool to study marine phytoplankton dynamics with unprecedented spatial and temporal coverage. Standard empirical Chl-a algorithms perform well where phytoplankton is the dominant optically active component in seawater, but usually fail in those regions where there is a high optical influence from multiple dissolved and particulate components that are not covariant with Chl-a (Prieur and Sathyendrenath, 1981). Therefore, in coastal regions, where colored dissolved and suspended particulate matter are dominant, it is crucial to perform an accuracy assessment of satellite Chl-a products to ensure their reliable use.Fil: Delgado, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Pratolongo, Paula Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Dogliotti, Ana Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina. Instituto Franco-Argentino sobre Estudios del Clima y sus Impactos; ArgentinaFil: Arena, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Celleri, Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Garzon Cardona, John Edison. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Martínez, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur. Departamento de Química; Argentin

Dynamics of herbaceous communities subject to different hydrological regimes in the lower Delta of the Paraná river and their monitoring using remote sensing data

En este trabajo se evaluaron la productividad primaria neta, la dinámica de la biomasa, la acumulación de materia orgánica y las tasas de descomposición en juncales de Schoenoplectus californicus y pajonales de Scirpus giganteus del Bajo Delta del río Paraná. El análisis se realizó en dos escalas diferentes, considerando tanto la comparación de las respuestas funcionales de la vegetación, ante situaciones hidrológicas contrastantes, como la evaluación de los patrones espaciales de fijación de carbono en una escala de paisaje. En ambas escalas de análisis y en todos los ambientes estudiados, se encontró una fuerte correspondencia entre mayores niveles de circulación superficial del agua y valores más altos de productividad primaria neta. Se encontró además, que el régimen hidrológico determina cambios en la capacidad de los ambientes para retener la biomasa producida y condiciona los patrones de acumulación de materia orgánica en el suelo. A partir de los resultados obtenidos, se realizó una caracterización funcional de estos ambientes y se estableció un modelo de cambios de estado en los niveles de energía que aporta una visión complementaria al modelo clásico de reemplazo de especies de la zona frontal del Bajo Delta.Present work in the Lower Delta of the Paraná River, evaluated the net primary production, biomass dynamics, organic matter accumulation and decomposition rate in Schoenoplectus californicus and Scirpus giganteus marshes. This study was performed at two different scales, through comparisons of the vegetation functional response in relation to different hydrologic situations, at a local scale, as well as the evaluation of spatial patterns of carbon sequestering, at a landscape scale. In every case, it was found that the higher the superficial runoff, the greater the net primary production values. Furthermore, the hydrologic regime determines differences in the biomass retention abilities and sets up the organic matter accumulation patterns in the soil. Starting from obtained results, a functional characterization was stated for these marshes and a model was derived based on energetic changes of state, which gives a complimentary point of view to the classic model of species replace in the frontal zone of the Lower Delta.Fil: Pratolongo, Paula Daniela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Salt Marshes and Mangroves: Tidal Saline Wetlands Dominated by Vascular Plants

Coastal wetlands encompass an ecosystem continuum between subtidal depths (to which light penetrates to support photosynthesis) and the landward edge of sea level influence. A broader definition of coastal wetlands includes, in addition to salt marshes and mangroves, a wide diversity of environments, from tidal flats, to non-tidal wetlands at the landward edge, whose hydrology is still influenced by sea level. In humid climates, freshwater seepage and high groundwater levels fed by excess rainfall provide the waterlogged conditions necessary for the establishment and growth of peat-forming wetlands. Freshwater swamps, Pocosins, non-tidal marshes, and bogs develop in shore zones under humid climates, beyond the limits of tidal influences. For these wetlands, water from terrestrial sources (groundwater seeps and often perched water tables) cause the inundation, but sea level modulates their hydrology and impedes drainage. In the shore zone of arid climates, under a combination of high evaporation and low freshwater inputs, soils develop extremelyhigh salinities. Extensive barren salt flats or halophytic steppes characterize arid coastal lowlands instead of freshwater swamps and bogs. These flat salt-crusted wetlands in arid shore zones are never flooded by tides but sea level keeps a shallow water table near the surface. This chapter focuses on the two ecosystems dominated by vascular plants along the intertidal zone. Tidal salt marshes dominated by herbaceous or low shrubby halophytic vegetation occur on protected shorelines from the Arctic to the subtropics. Mangrove communities dominated by halophytic treesreplace salt marshes in tropical regions worldwide, although they may even extend into subtropicalregions where ocean currents ameliorate temperatures. While salt marshes still occur in the tropics, they cover a smaller area than mangroves. Despite their different appearance, salt marshes and mangroves are remarkably similar in terms of their ecological functions and relevanceFil: Pratolongo, Paula Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

Soft-bottom Marine Benthos

The term benthos applies to the organisms that inhabit ocean bottoms. Benthos distribution is controlled by a combination of factors such as sediment granulometry, dissolved O2, OM content, as well as disturbance and pollution. Functional classifications of soft-bottom marine benthos may follow different criteria, namely, size (micro-, meio- and macrobenthos); habitat preference (epifauna, infauna); feeding strategies (shredders, grazers, suspension- and deposit feeders); type of carnivory (predators and scavengers); or their contribution to sediment stability and/or erodibility (stabilizers and bioturbators). Deep-sea benthic ecosystems harbor a high biological diversity and several hypotheses have been invoked to explain such diversity and distribution patterns. Deep-sea ecosystems may be divided into two major groups, heterotrophic and chemosynthetic habitats, in relation to the energy fuelling them. Soft-bottom ecosystems play a major role in nutrient regeneration, through the processing of OM coming from different sources. The pelagic and benthic sub-systems are interconnected through physical or biologically-mediated processes, collectively known as benthic-pelagic coupling (BPC). Suspension-feeding, an example of biological BPC, is an energy-acquisition strategy convergently evolved among many phyla of marine organisms, that targets a profit from the large amount of particles suspended in seawater. There is no analogous mechanism to suspension-feeding in terrestrial ecology.Fil: Pan, Jeronimo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Pratolongo, Paula Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentin

Introduction to the Marine Environment from Physical and Chemical Perspectives

The oceans and the atmosphere exchange heat, salt, water, and momentum, and most physical andchemical processes in the oceans result from this interaction. Winds blowing over the ocean transfer energy to the surface layers allowing for the development of ocean currents. Solar radiation can evaporate water, removing heat from the ocean that is transferred to the atmosphere when water vapor is condensed into clouds. Evaporation and freezing, both resulting from the ocean-atmosphere interaction, turn liquid water saltier, but rainfall dilutes the salt concentration of the surface ocean. As mentioned, there are many feedback mechanisms between the oceans and the atmosphere. In the next sections, we will introduce some of the physical and chemical properties of the marine environment that result from the ocean atmosphere coupling and are relevant for marine life. Our coverage of these topics is by no means exhaustive, nor at length, but rather aiming to provide the basics anyone interested in marine biology should be familiar with. Those readers interested in more thorough and quantitative treatments of these topics should refer to specific oceanography and biogeochemistry textbooks.Fil: Pratolongo, Paula Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Pan, Jeronimo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

The Bahía Blanca Estuary in a regional context

The aim of this introductory chapter is to provide the readers some insight into the regional context of the Bahía Blanca Estuary. We begin this chapter with a description of the geological settings along the Atlantic coast of South America. Central to this issue is the evolution of the relative sea level during the Holocene, which shaped the landscape structure of major coastal wetland systems. Regarding the regional climate, central east Argentina is characterized by a large interannual rainfall variability and by a strong gradient of decreasing rainfall from the northeast to the southwest. Vegetation types along this area are strongly associated with the regional precipitation gradient, ranging from grasslands in the northeast to xerophytic shrublands and bushy steppes in the southwest. In the marine realm, the Bahía Blanca Estuary belongs to the Large Marine Ecosystem called Patagonian Shelf, characterized by the extensive mixing of the Malvinas and the Brazil Currents. El Rincón, in the coastal zone off the Bahía Blanca Estuary, is a highly productive area due to the occurrence of elevated densities of fish and zooplankton. The availability of adequate food, suitable thermal and salinity ranges, and the oceanic circulation that favors a retention mechanism would facilitate fish larval recruitment and growth of valuable commercial species.Fil: Pratolongo, Paula Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Fiori, Sandra Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin

Net aboveground primary production and soil properties of floating and attached freshwater tidal marshes in the Rio de la Plata estuary, Argentina

In the lower delta of the Parana´ River, at the head of the Rı´o de la Plata estuary (Argentina), we compared net aboveground primary production (NAPP) and soil properties of the dominant macrophyte Scirpus giganteus (Kunth) in a floating and an attached marsh community. Both marshes are tidally influenced but in different ways. The floating marsh site is relatively isolated from tidal influences because its ability to float makes it resistant to overland flow and to sediment inputs from the estuary. The attached marsh lacks the capacity to float and receives sediment supplies from the estuary through overland flow. These hydrologic differences are reflected in lower mineral content in sediments of the floating marsh. Using a leaf tagging technique, estimated NAPP was 1,109+-206 g m-2 y r-1 for the floating marsh and 1,866+-258 g m-2 y r-1 for the attached marsh. We attribute the lower NAPP of the floating marsh to isolation from sediment input from overland flow.Fil: Pratolongo, Paula Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Kandus, Patricia. Universidad de Buenos Aires; ArgentinaFil: Brinson, Mark. East Carolina University; Estados Unido