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Olivancillaria carcellesi occurs in shallow sandy shores from north Patagonia, in intertidal and subtidal sandy bottoms. Females of O. carcellesi exhibited a remarkable specificity for spawning on the shells of living males and females, indiscriminately, of the buccinanopsid Buccinastrum deforme, measuring 26.9 ± 4.7 mm in shell length. The egg capsule was semispherical and attached to B. deforme shells by a small elliptical and wide base. The capsule was translucid when spawned, with a thick and semirigid wall and a hatching aperture of 1.8 ± 0.1 mm (n = 111) in diameter. Each egg capsule contained a single egg that measured 1367 ± 34 μm (n = 5) in diameter before cleavage. The embryo developed a small bilobed velum and an operculum, which were both lost before hatching as a crawling juvenile of 1762 ± 47 μm (n = 28) in shell length. As in other species in the genus, the eggs of O. carcellesi are among the largest in the caenogastropods with direct development. The time from oviposition to hatching is estimated to be approximately 6 months. [ABSTRACT FROM AUTHOR]

This is the first exploratory study that addresses simultaneously the phytoplankton and mesozooplankton seasonal dynamics associated with some environmental factors in the northern Patagonian gulfs: Golfo Nuevo (GN) and Golfo San José GSJ), Argentina, during an annual cycle (December 2014–2015 and January 2015–2016, respectively). It also reports data on mesozooplankton composition and abundance in a sample collected while southern right whales ( Eubalaena australis ) were feeding at the sea surface in Bahía Pirámide (GN). The phytoplankton community was represented by 69 taxa in GN and by 83 taxa in GSJ. In GN, phytoplankton was mainly dominated by diatoms and dinoflagellates whereas in GSJ diatoms dominated the phytoplankton community throughout the year. In GN, the highest phytoplankton biomass and density values were registered during austral spring, 2015 which coincided with a Pseudo-nitzschia australis bloom. In contrast, the lowest biomass values, which were associated with elevated abundances of dinoflagellates, were observed in late spring 2014. In GSJ, the highest biomass values showed two equal peaks in austral autumn and spring 2015. The latter was associated with the maximum cell density recorded in this gulf during a Chaetoceros debilis bloom. In contrast, the lowest biomass values were recorded in winter 2015. Mesozooplankton was represented by 63 taxa in GN and by 61 taxa in GSJ. In GN, this community was mainly represented by cladocerans and copepods, whereas it was dominated by copepods in GSJ. The lowest mesozooplankton abundances were recorded in austral winter in both gulfs. In GN, the highest abundances were recorded in austral summer and spring 2015, whereas in GSJ, the maximum mesozooplankton abundances were observed during austral summer and autumn 2015. The major prey items for E. australis were the copepods Calanoides carinatus , Ctenocalanus vanus , Calanus australis , and Paracalanus parvus , zoeae of the squat lobster Munida gregaria , calyptopis and furcilia of Euphausia lucens , and fish eggs and larvae. In both gulfs, the warm seasons were mainly characterized by higher relative abundances of diatoms, while the cold seasons were mostly associated with higher abundances of dinoflagellates and Dictyochophyceae. Salinity and phaeopigments were related with copepod and appendicularian abundances, whereas surface sea water temperature seemed to modulate the seasonal distribution pattern of cladocerans and decapods. [ABSTRACT FROM AUTHOR]

Semidiurnal (M 2 , S 2 , N 2 and K 2 ), diurnal (K 1 ,O 1 and P 1 ) and quarter-diurnal (M 4 , MN 4 and MS 4 ) barotropic tides over the North Patagonian Gulfs of Argentina: San Matías, (SMG), Nuevo (NG) and San José (SJG) are examined using a regional numerical model. Detailed comparison of computed elevations and currents with those obtained from harmonic analysis of few long-term observational records showed good agreement. A large amplification of all semidiurnal waves is recorded when they cross SMG mouth. Most of the tidal energy coming from the south at this frequency dissipates to the northeast of Valdés Península, where the largest tidal currents are located. While M 2 currents (up to 2–2.5 m/s) are dominant, there are large S 2 and N 2 currents and locally intensified diurnal currents (5–10 cm/s) in some outer shelf locations. At difference with the semidiurnal and diurnal tides the higher harmonics M 4 , MS 4 and MN 4 develop a large amplification inside the NG. The model revealed a complex field of tidal residual currents. The intensity of such currents in some locations are of the same order of magnitude as those generated by winds or offshore forcing. We have identified three main patterns of residual circulation: regional coastal currents and gulf-wide gyres; inlet eddies and, topographic eddies. Vorticity balances and sensitivity experiments indicate that non-linear advection and bottom topography are the key mechanisms involved in the generation of these residual structures. [ABSTRACT FROM AUTHOR]

En este trabajo se presentan los resultados de un modelo hidrodinámico barotrópico de alta resolución no-lineal tridimensional para examinar la respuesta de los golfos norpatagónicos argentinos, San Matías (GSM), Nuevo (GN) y San José (GSJ), ante forzante de marea y patrones idealizados de viento superficial. La estructura de la circulación inducida por el viento predominante (Oeste) en los tres golfos consiste en dos giros independientes: uno anticiclónico en el Oeste con una corriente costera más intensa que fluye hacia el sur y un retorno más débil por el centro de los golfos y otro giro ciclónico en el Este, que establece la conexión con la Plataforma en el caso del GSM. El GN y GSJ tienen la comunicación con el exterior muy restringida. La inclusión de efectos disipativos producidos por la marea reduce la intensidad de los giros, pero la estructura espacial de la circulación permanece. Si se incrementa la magnitud del viento se intensifican principalmente los giros anticiclónicos y el transporte de intercambio en la boca del GSM y se profundiza la capa superficial de Ekman. En los experimentos forzados con vientos meridionales la circulación media se divide en dos giros cuyo sentido de circulación depende de la dirección del viento: un giro Norte ciclónico (anticiclónico) y un giro Sur anticiclónico (ciclónico) para vientos del Sur (Norte). Cuando los golfos son forzados simultáneamente por marea y vientos, las corrientes residuales de marea dominan la circulación media y contribuyen a un mayor aislamiento dinámico de los mismos con la plataforma exterior.This work presents the results of a high resolution three dimensional non-linear barotropic hydrodynamic model used to examine the response of three north Patagonian gulfs in Argentina (San Matías, SMG; Nuevo, NG; and San José, SJG) forced by tides and idealized patterns of surface winds. The structure of the circulation induced by the dominant winds (Westerly) in all three gulfs consists of two independent gyres: one anticyclonic gyre in the west with an intense southward coastal flow and weaker return flow in the middle of the gulfs and one cyclonic gyre in the east that, in the SMG's case, connects with the shelf. The other two gulfs (NG and SJG) have much more restricted connections with the exterior. The inclusion of tidal dissipation effects reduces the intensity of the gyres, but the general spatial pattern of the circulation remains. Increasing the wind magnitude mainly intensifies the anticyclonic gyre and the cross-shelf transport through the SMG mouth and deepens the surface Ekman layer. If the gulfs are forced with meridional winds, the circulation splits into two gyres whose sense of circulation depends on the wind direction: a northern cyclonic (anticyclonic) gyre and a southern anticyclonic (cyclonic) gyre for Southerly (Northerly) winds. When the gulfs are forced simultaneously by tides and winds, the residual tidal currents dominates the general circulation and contributes to a greater dynamical isolation of the gulfs from the exterior shelf.

This work presents the results of a high resolution three dimensional non-linear barotropic hydrodynamic model used to examine the response of three north Patagonian gulfs in Argentina (San Matías, SMG; Nuevo, NG; and San José, SJG) forced by tides and idealized patterns of surface winds. The structure of the circulation induced by the dominant winds (Westerly) in all three gulfs consists of two independent gyres: one anticyclonic gyre in the west with an intense southward coastal flow and weaker return flow in the middle of the gulfs and one cyclonic gyre in the east that, in the SMG's case, connects with the shelf. The other two gulfs (NG and SJG) have much more restricted connections with the exterior. The inclusion of tidal dissipation effects reduces the intensity of the gyres, but the general spatial pattern of the circulation remains. Increasing the wind magnitude mainly intensifies the anticyclonic gyre and the cross-shelf transport through the SMG mouth and deepens the surface Ekman layer. If the gulfs are forced with meridional winds, the circulation splits into two gyres whose sense of circulation depends on the wind direction: a northern cyclonic (anticyclonic) gyre and a southern anticyclonic (cyclonic) gyre for Southerly (Northerly) winds. When the gulfs are forced simultaneously by tides and winds, the residual tidal currents dominates the general circulation and contributes to a greater dynamical isolation of the gulfs from the exterior shelf. [ABSTRACT FROM AUTHOR]