Seasonal variability of metazooplankton in coastal sub-Antarctic waters (Beagle Channel)

Aguirre, Gastón E.; Capitanio, Fabiana L.; Lovrich, Gustavo A.; Esnal, Graciela B.

doi:10.1080/17451000.2011.627922

Cited by 42 publications

(29 citation statements)

References 37 publications

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“…Copepods were the dominant metazooplankton group at the study site, as observed in other temperate coastal regions (Hopcroft et al 2001, Aguirre et al 2012). Copepods play a key role in the pelagic carbon flux because of their capability of taking up energy from the microbial food web and transferring it to higher trophic levels (Turner 2004, Viñas et al 2013.…”

Section: Discussionmentioning

confidence: 64%

“…Los copépodos fueron el grupo de metazooplancton dominante en el sitio estudiado, como se ha observado en otras regiones costeras templadas (Hopcroft et al 2001, Aguirre et al 2012. Los copépodos juegan un papel clave en el flujo de carbono pelágico debido a su capacidad para tomar la energía de la red trófica microbiana y transferirla a los Table 3.…”

Section: Discussionunclassified

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Diversity of copepods in Atlantic Patagonian coastal waters throughout an annual cycle

Spinelli

Gonçalves²,

Villafañe³

et al. 2016

Cienc. Mar.

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ABSTRACT. The aim of this study is to analyze the annual zooplankton succession at a coastal station in Patagonia (Argentina), with special emphasis on copepods and their potential preys, using solar radiation and temperature as environmental factors. The annual plankton cycle exhibited autumn/winter and spring/summer phases. During the autumn/winter phase, low temperature and radiation were correlated with higher diatom abundance and copepod diversity. This period was characterized by a dominant classical herbivorous food web in which the large copepod Calanoides carinatus dominated the community. On the contrary, during the spring/summer period, with high radiation and temperature levels, flagellates were the dominant food available for zooplankton and correlated with smaller species of copepods such as the harpacticoid Euterpina acutifrons. Also, intensive reproduction of the small copepods E. acutifrons and Paracalanus parvus occurred mainly in summer. On the other hand, high species diversity was found in winter when the ultraviolet radiation was low. The temporal pattern of the copepods observed in our study was explained by food availability and environmental factors (temperature and solar radiation), although other factors such as predator abundance may also be important in modulating the community. Our results show the importance of copepod abundance dynamics and highlights their key role in the pelagic food web in northern Patagonian coastal waters.Key words: zooplankton, harpacticoid copepods, Argentinean Sea, phytoplankton.RESUMEN. El objetivo de este estudio es analizar la sucesión anual del zooplancton en una estación costera en la Patagonia (Argentina), con especial énfasis en copépodos y sus posibles presas, en relación con la radiación solar y la temperatura como factores ambientales. El ciclo anual del plancton mostró dos periodos, otoño/invierno y primavera/verano. Durante el periodo otoño/invierno, la baja temperatura y la radiación se correlacionaron con la mayor abundancia de diatomeas y la mayor diversidad de copépodos. Este periodo se caracterizó por la dominancia de la cadena clásica herbívora, y el copépodo grande Calanoides carinatus dominó la comunidad. Por el contrario, durante el periodo de primavera/verano, con alta radiación y mayores niveles de temperatura, los flagelados fueron el alimento disponible para el zooplancton y se correlacionaron con las especies pequeñas de copépodos como el harpacticoideo Euterpina acutifrons. Además, la reproducción intensiva de los copépodos pequeños E. acutifrons y Paracalanus parvus se llevó a cabo principalmente en verano. Por otro lado, se encontró una alta diversidad de especies en invierno, cuando la radiación ultravioleta fue baja. El patrón temporal de los copépodos observado en nuestro estudio fue explicado por la disponibilidad de alimento y los factores ambientales (temperatura y radiación solar), aunque otros factores tales como la abundancia de los depredadores pueden ser también importantes en la modulación de la comunidad. Nuestros ...

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Section: Discussionmentioning

confidence: 64%

Section: Discussionunclassified

Diversity of copepods in Atlantic Patagonian coastal waters throughout an annual cycle

Spinelli

Gonçalves²,

Villafañe³

et al. 2016

Cienc. Mar.

View full text Add to dashboard Cite

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“…This bottom-up regulation has been reported frequently in populations of appendicularians (BÅMSTEDT et al, 2005). AGUIRRE et al (2012) observed that the highest densities of F. borealis in the Beagle Channel during spring coincided with the maximum values of surface chlorophyll-a. In the present study, the highest densities of F. borealis were registered in spring and summer while the maximum values of chlorophyll-a occurred in late winter.…”

Section: Discussionmentioning

confidence: 89%

“…During the seasonal cycle at a Buenos Aires coastal station (38º28´S, 57º41´W), its highest densities occurred during the autumn-winter period, coinciding with the lowest temperatures (CAPITANIO et al, 2008). Also, in the subAntarctic region, AGUIRRE et al (2012), who studied the seasonal variation in the composition and abundance of metazooplankton in different bays of the Beagle Channel, reported that this species is widely distributed in these coastal zones. F. borealis was an important component of zooplankton in spring (November), coinciding with maximum values of chlorophyll-a.…”

Section: Introductionmentioning

confidence: 99%

Population structure and maturity stages of Fritillaria borealis (Appendicularia, Tunicata): seasonal cycle in Ushuaia Bay (Beagle Channel)

2015

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Fritillaria borealis is a cosmopolitan species, very frequent in sub-antarctic and antarctic waters. The objective of this paper was to analyze its size structure and maturity stages at two sites in Ushuaia Bay: a coastal site exposed to anthropogenic pressure (E1) and a reference site (E2) located in the external zone of the bay. Zooplankton was collected during the 2012 seasonal cycle. The sampling method involved the use of a 67 µm-mesh net. Appendicularians were classified in four maturity stages: I) undifferentiated gonads, II) testis and ovary differentiated, III) expanded testis, IV) discharged testis, expanded ovary. Our results showed that the highest densities of F. borealisoccurred in spring and summer at both sites; coinciding with high values of chlorophyll-a. The percentage of juveniles (I and II) exhibited a spatial and temporal pattern similar to that observed for chlorophyll-a values. During spring-summer, juveniles and mature specimens (III and IV) showed a greater gonadal development than those individuals found in autumn-winter. In conclusion, the mismatching in the population structure and the pattern of densities of F. borealis between coastal and external zones would suggest the existence of two sub-populations susceptible to the influence of the anthropogenic impact in the bay.

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“…The Beagle Channel is located at the southern tip of South America and is a sub-Antarctic coastal marine-estuarine environment (Isla et al 1999;Aguirre et al 2012). The environmental conditions are markedly seasonal: sea surface temperature in the lower intertidal zone ranges from 5.2°C in August to 9.5°C in January (Laboratorio Biología de Crustáceos, CADIC, unpublished data).…”

Section: Study Areamentioning

confidence: 99%

Moult cycle and growth of the crab Halicarcinus planatus (Brachyura, Hymenosomatidae) in the Beagle Channel, southern tip of South America

Diez

Lovrich

2012

Helgol Mar Res

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The crab Halicarcinus planatus is the only hymenosomatid crab that inhabits the southern tip of South America and is the only decapod species that reproduces twice a year in the Beagle Channel. In this article, we study the moult cycle in the field (moult frequency, analysis of size frequency distribution) and linked it with growth studied in the laboratory (absolute and per cent growth increment, Hiatt function). Hiatt functions were similar for males and females. Moult frequency was seasonal: in early austral spring and in austral summer. In females, the pubertal moult is the terminal moult, whereas males continue moulting after attaining the size of morphometric maturity. Moult increment was highly variable. The relationship between absolute moult increment and crab size was described by a quadratic function. Per cent growth increment decreased with size, and relationships were different for each sex: linear for females and quadratic for males. Seven and eight modal groups explained the size frequency distributions for females and males from the field, respectively, and revealed the existence of two cohorts of recruits per year. Further modal analysis was mainly hampered by the high variability of size increment that could make any moulting individual fall in its own or one of two following modal groups. The antagonism between growth and reproduction was evident in small males. We hypothesize that the terminal pubertal moult is an advantageous feature that allows females to maximize their investment in reproduction after their terminal moult, which allows this species to have two spawnings per year.

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Seasonal variability of metazooplankton in coastal sub-Antarctic waters (Beagle Channel)

Cited by 42 publications

References 37 publications

Diversity of copepods in Atlantic Patagonian coastal waters throughout an annual cycle

Diversity of copepods in Atlantic Patagonian coastal waters throughout an annual cycle

Population structure and maturity stages of Fritillaria borealis (Appendicularia, Tunicata): seasonal cycle in Ushuaia Bay (Beagle Channel)

Moult cycle and growth of the crab Halicarcinus planatus (Brachyura, Hymenosomatidae) in the Beagle Channel, southern tip of South America

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