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Notochthamalus scabrosus (N.s.) and Elminius kingii (E.k.) found in the western coast of Bahía Lapataia, Tierra del Fuego, Argentina.
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... scabrosus (Darwin, 1854) is commonly attached to littoral rocks and shells, often associated with Notobalanus flosculus (Darwin, 1854), and sometimes with Chthamalus cirratus (Darwin, 1851). Notochthamalus scabrosus was previously reported from Peru to Tierra del Fuego and Islas Malvinas / Falkland Islands by Darwin (1851). Moreover, the review of South American barnacle distribution by Young (1995) suggested that the temperate zone of the Southwestern At- lantic, occurring between 35oS and the southern tip of South America (56oS), had a barnacle fauna similar to that of the Southeastern Pacific (coasts of Chile and Peru), with N. scabrosus occurring at both zones. Particularly in the Beagle Channel, N. scabrous is the dominant species in the upper zone of the rocky intertidal. The Beagle Channel is located at the south- ernmost tip of South America ( ca. 55o S; 68o W) and is an ancient glacial valley of about 210 km length and 5 km width, with different basins. The Beagle Channel has fjord estuarine features with salinities lower than the surrounding oceanic water masses due to the discharge of glaciers and rivers (Balestrini et al . 1998, Isla et al . 1999). One of these subsys- tems is the estuarine complex of Lago Roca-Bahía Lapataia, a palaeo-fjord currently constituted by a lake discharging freshwater to the channel via the Ovando River (Isla et al . 1999; Fig. 1). Zaixso et al. (1978) described the rocky intertidal flora and fauna from 11 localities at the Beagle Channel. N. scabrosus was reported by the authors from three localities: Bahía Ensenada (Ensenada Zaratiegui) (54o 50’ S; 68o 28’ W), Punta Jones (54o 49’ S; 68o 13’ W) and Bahía Ushuaia (54o 49’ S; 68o 19’ W). With regard to Bahía Lapataia, Zaixso et al. (1978) mentioned that this species was absent there, likely as a consequence of the low salinity characterizing the zone. Authors reported the presence of Elminius kingii (Gray 1831) as the only barnacle species for this location. In the present study we report for the first time the presence of N. scabrosus in the upper zone of the rocky intertidal of the western coast of Bahía Lapataia (54o 51.54’ S; 68o 33.87’ W), Tierra del Fuego (Fig. 1). Specimens of N. scabrosus were found along with Elminius kingii (Fig. 2). On September 25 th , 2008 photographs and samples of both species were taken. The samples were collected for accurate identification after dissection. Especially during spring and summer, Ensenada Zaratiegui and Bahía Lapataia have very variable and lower salinity than other sites of the Beagle Channel, which in turn are less influenced by freshwater discharges (Table 1). N. scabrous is clearly a euryhaline species since specimens can tolerate a range of salinities of 15 – 31 ups. Although there are no specific studies on salinity tolerance of this species, the genus Chthamalus is known to be euryhaline ( e.g. Crisp & Costlow 1963, López & González 2003, Farrapeira 2008). Roughgarden et al . (1988) and Alexander & Roughgarden (1996) have suggested that the ecology of a rocky intertidal community at a site would be governed by adult-adult interactions within the site, or by limitations to the supply of larvae reaching the site, the latter being determined by the regional pat- tern of circulation and physical oceanography in the coastal waters. These characteristics would explain the variation of timing of recruitment at the coast and the likely reason that it occurs in discrete pulses. We propose that the establishment of N. scabrosus in Bahía Lapataia could be a consequence of local hydrological events, namely coastal currents, wind direction and intensity and availability of larvae in the plankton rather than by the low saline waters characterizing the zone, and these events would explain the discontinuous scheme of distribution of N. scabrosus along the coast of the Beagle Channel. This channel is a particular environment because of its fjord features and its semi-closed condition (Antezana 1999). For example, the freshwater input may change the environmental conditions at a geographical micro-scale. In some western coves the ice input from glaciers may produce the typical coastal disturbance so that the intertidal community may be locally impoverished or absent ( c.f. Mutschke & Gorny 1999, Barnes 2005). Hence, the presence of certain species at different sites with both different freshwater input and coastal orientation –and therefore differentially affected by winds and currents– may be indicators of specific hydrological processes acting on the community structure and/ or ...
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... S, owing to local freshwater runoff from rivers and streams, but reaching 31.7‰ S as a result of evaporation, with an annual mean of ∼27‰ S (Curelovich et al., 2009). The Beagle Channel thus exhibits salinities slightly lower than that of seawater, and can be considered an estuarine regime in character (Isla et al., 1999). ...
Osmoregulatory findings on crabs from high Neotropical latitudes are entirely lacking. Seeking to identify consequences of evolution at low temperature, we examine hyper/hypo-osmotic and ionic regulation and gill ion transporter gene expressions in two sub-Antarctic Eubrachyura from the Beagle Channel, Tierra del Fuego. Despite sharing the same osmotic niche, Acanthocyclus albatrossis tolerates a wider salinity range (2-65 ‰S) than Halicarcinus planatus (5-60 ‰S); their respective lower and upper critical salinities are 4 and 12 ‰S, and 63 and 50 ‰S. Acanthocyclus albatrossis is a weak hyperosmotic regulator, while H. planatus hyper-osmoconforms; isosmotic points are 1,380 and ≈1,340 mOsm kg-1 H2O, respectively. Both crabs hyper/hypo-regulate [Cl-] well with iso-chloride points at 452 and 316 mmol L-1 Cl-, respectively. [Na+] is hyper-regulated at all salinities. mRNA expression of gill Na+/K+-ATPase is salinity-sensitive in A. albatrossis, increasing ≈1.9-fold at 5 compared to 30 ‰S, decreasing at 40 to 60 ‰S. Expression in H. planatus is very low salinity-sensitive, increasing ≈4.7-fold over 30 ‰S, but decreasing at 50 ‰S. V(H+)-ATPase expression decreases in A. albatrossis at low and high salinities as in H. planatus. Na+-K+-2Cl- symporter expression in A. albatrossis increases 2.6-fold at 5 ‰S, but decreases at 60 ‰S compared to 30 ‰S. Chloride uptake may be mediated by increased Na+-K+-2Cl- expression but Cl- secretion is independent of symporter expression. These unrelated eubrachyurans exhibit similar systemic osmoregulatory characteristics and are better adapted to dilute media; however, the gene expressions underlying ion uptake and secretion show marked interspecific divergences. Cold clime crabs may limit osmoregulatory energy expenditure by hyper/hypo-regulating hemolymph [Cl-] alone, apportioning resources for other energy-demanding processes.
... Both N. scabrosus and J. cirratus can be found in the mid-to-high intertidal along the entire coast of Chile, with populations in Peru and southernmost Argentina as well (Curelovich et al., 2009). Typically, they overlap greatly in vertical range, with J. cirratus tending to be more abundant in the high intertidal and N. scabrosus more abundant in the mid-intertidal (Shinen & Navarrete, 2014); yet there is no evidence that they competitively exclude each other from these zones (Shinen & Navarrete 2014) nor that they have distinct thermal tolerances (Lamb et al., 2014). ...
In the past 40 years, the ability to distinguish phenotypically similar species by using molecular methods has rapidly changed the study of taxonomy, biogeography, and community diversity. A cosmopolitan family of acorn barnacles, Chthamalidae Darwin, 1854, can be found on almost every non-boreal coast, with very similar habitat requirements, larval life histories, and external (test) morphologies among its species. Here I review how molecular methods have aided the description of new species as well as the characterization of phylogenetic diversity within species, and also broadened our understanding of the biogeography of this family. Multiple regional analyses have shown that the coastal habitat appears to drive diversity and diversification in generally similar ways regardless of location, while a global perspective allows us to identify regions and questions that merit further study. Variation in the spatial patterning of genomic diversity among species sometimes provides evidence as to how key life history parameters determine responses of species to ocean currents and forcing, thermal environments, and competition.
... Tides are semidiurnal; the surface water temperature ranges from 4.48C in August to 9.48C in January. Salinity reaches an average of 24 psu during November-March, attaining local minimum values as low as 15 psu in nearshore waters (Curelovich et al., 2009). ...
This study presents for the first time the factors governing the recruitment in a rocky intertidal community of the Beagle Channel, Tierra del Fuego (54°51′S 68°29′W), Argentina. The aim of this study was to examine the effect of grazers and predators, free substrate availability and crustose coralline algae on the recruitment of the main sessile components of the intertidal: Notochthamalus scabrosus, Notobalanus flosculus, Mytilus chilensis, Perumytilus purpuratus and Aulacomya atra at three intertidal levels. For barnacles, the probability of recruitment was higher with grazers, while the contrary was observed for bivalves. The number of N. flosculus recruits was higher with increased substrate availability, while N. scabrosus recruited more with reduced free substrate in the first sampling. Mussel recruitment was higher with reduced free substrate. The highest probability of recruitment of N. scabrosus was observed at the upper level. Notably, this probability and the recruits per plot were higher at the mid level under uncaged-ORP treatment than expected for the mid level. The probability of bivalve and N. flosculus recruitment was higher at upper and lower levels, respectively. At the lower level, barnacle recruitment was higher on bare rock than on crustose coralline algae. Our results suggest that grazers increase the probability of barnacle recruitment, while the presence of sessile organisms enhances the density of mussel recruits. Almost no recruitment of bivalves was observed in ORPs over one year, showing that the secondary succession is slow in this environment.
... Calcagno et al. ( , 1998), Calcagno y Luquet (1997) y López estudiaron diversos aspectos de la ecología de A. amphitrite en sitios expuestos a la contaminación en la provincia de Buenos Aires. En el Canal Beagle, Zaixso et al. (1978) describieron los patrones de distribución vertical de N. scabrosus y Elminius kingii en el intermareal, y Curelovich et al. (2009) registraron por primera vez la presencia de N. scabrosus en Bahía Lapataia . Otra especie de cirripedios presente en el extremo sur de Argentina es N. flosculus. ...
... For a typical cline, we might expect the B clade to go toward fixation in samples taken further south (but see Wares and Cunningham 2005); instead, it never is found at frequency greater than 30%. While additional information may be necessary from populations of N. scabrosus still further south (it is found as far south as Beagle Channel in southern Argentina; (Curelovich et al. 2009), the behavior of this evolutionary lineage is much like a cryptic species with more restrictive physiological tolerances (Schizas et al. 2001). Sequence data from a single nuclear marker (elongation factor 1-alpha) suggested that the major haplogroups in N. scabrosus are randomly mating (Zakas et al. 2009); additional data from the nuclear genome will be necessary to evaluate the potential mechanisms maintaining the distributional edge of this lineage. ...
A significant genetic cline has previously been identified along the Chilean coast in the barnacle Notochthamalus scabrosus. Samples from the previous study, spanning 800 km, were not able to show whether the southern lineage ultimately goes to fixation at higher latitudes. In addition to expanding the geographic sampling of this species, locations that were sampled approximately four to five generations ago were resampled for this study, enabling a temporal comparison of the location and strength of the observed cline. Here, we show that although the cline persists as expected, the tremendous changes in observed lineage frequencies near the clinal boundary are indicative of source-sink dynamics that may be associated with a codistributed biogeographic transition zone. We also find that the southern lineage does not increase in frequency in more southern populations, suggesting that this lineage is maintained through a combination of density-dependent interactions and a coastal fitness gradient.
La ecorregión subantártica de Magallanes posee una heterogénea costa de fiordos y canales, con una gran extensión de ecosistemas intermareales sujetos al efecto de condiciones climáticas extremas características de zonas de altas latitudes. Trabajos de investigación recientes sugieren que la estructura de los ensambles intermareales que habitan en ambientes extremos, como subantárticos y antárticos, presenta altas variaciones horizontales y verticales que se acentúan a escalas espaciales finas. Éste podría ser un patrón general en hábitats intermareales de altas latitudes del hemisferio sur, y en este trabajo evaluamos la hipótesis que la variabilidad horizontal y vertical de los ensambles bentónicos intermareales en ambientes extremos subantárticos es mayor a escalas finas. En marzo-abril de 2017 se analizó la variabilidad espacial sobre los ensambles bentónicos intermareales de bahía Yendegaia, Reserva de la Biosfera Cabo de Hornos, como modelo de estudio con un diseño anidado con diferentes escalas espaciales que van desde centímetros a kilómetros. El análisis de los componentes de varianza y pseudo-varianza mostró una significativa variación horizontal y vertical a escalas finas. Se identificaron seis comunidades con una marcada zonación vertical. Las especies más representativas fueron el molusco Perumytilus purpuratus y las algas Porphyra/Pyropia sp1. y Ulva flexuosa, las que tuvieron una alta variación vertical en escalas finas. Estos patrones apoyan la hipótesis testeada, sin embargo, es probable que factores físicos locales del hábitat relacionados con cambios abióticos también influyan significativamente sobre las variaciones espaciales a pequeñas escalas en las comunidades de bahía Yendegaia. Por lo tanto, se propone extender este tipo de investigaciones incorporando la variabilidad temporal y datos ambientales en bruto. Estos estudios permitirán detectar los factores locales más influyentes sobre la variación espacial de los ensambles bentónicos intermareales subantárticos.
Live transport to markets requires a baseline on the effects of temperature during air-exposure and the subsequent recovery in water. Our aim was to analyze the physiological effect of 24 h of air exposure in commercial male Lithodes santolla at different temperatures and subsequent re-immersion. Three groups of animals were air-exposed at three temperatures (4 °C, 8 °C and 12 °C) for 24 h, and then re-submersed for 12 h. The control group was kept in water at 8 °C. Samples of haemolymph were extracted after air exposure and re-immersed. We measured superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), ascorbic acid (AA), and protein oxidation (PO). Animals exposed at 12 °C died during emersion. Almost all measured parameters changed with air exposure and temperature. The total recovery of most of the analyzed oxidative stress parameters was attained only at 8 °C, where SOD, CAT and GPx, AA, glucose, and pH returned to values similar to the control group. In animals exposed at 4 °C, only SOD and AA returned to basal levels. Acclimation temperature is an important parameter to consider in the shipping-stock chain of L. santolla, since changes in temperature might be an extra factor of stress during recovery of the animal, besides the reperfusion itself.
The crab Halicarcinus planatus (Fabricius, 1775) is the only member of Hymenosomatidae that inhabits the southern tip of South America, and it is the only decapod species that reproduces twice a year in the Beagle Channel. In this study, we analysed seasonal variations in development duration, body size, biomass (dry weight), and elemental composition (CHN) of larvae from a population living at the southernmost limit of the species' geographic range. Compared to offspring produced in December (early summer), larvae released in August (late winter) were on average larger and heavier, and they showed a higher carbon content (suggesting a larger lipid fraction). This pattern of intraspecific variation in larval size and biomass corresponds with minimum primary productivity in sub-Antarctic regions during winter, suggesting that large winter eggs may represent a reproductive adaptation to a regular pattern of variation in nutritional conditions, including food limitation in winter. As an additional or alternative explanation, also strong salinity fluctuations occurring in summer might reduce larval quality in the December cohort. In conclusion, seasonal variation in larval size and biomass may be related to variations in nutritional and/or physical factors.
