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      Distribution of the species of Lucifer Thompson, 1829 in the subtropical South Atlantic between parallels 20º and 30ºs

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          Abstract

          Abstract The distribution of the species of Lucifer Thompson, 1829 (Decapoda: Luciferidae) in the South Atlantic Subtropical Gyre was assessed by the Brazil Transatlantic Commission in November and December 2009. The samples were collected at 83 stations on two profiles between Brazil and Africa (20 º and 30 ºS). Oblique hauls were performed with a WP-2 net up to 150 meters deep. A distinct sexual relationship was noted between the two species found and L. faxoni presented a significantly higher number of females relative to males 1:0.5 (X2 = 21.77, p = 0.0001). The L. typus sex ratio had significantly more males than females 1.86:1 (X2=50.84, p = 0.0001). The distribution of L. typus occurred in both the western and the eastern portions of the Mid-Oceanic Ridge. This distribution was significantly related to salinity (R2 = 0:13; F = 3.79, p = 0.009), which was higher in the western portion of the study area. In addition, the recordings of the two species were extended to the Atlantic Subtropical Gyre. Overall, Luciferidae shrimp were more common and abundant at the stations west of the Mid-Oceanic Ridge and L. typus was the most frequent and abundant species.

          Translated abstract

          Resumo A distribuição das espécies de Lucifer Thompson, 1829 (Decapoda: Luciferidae) no Giro Subtropical do Atlântico Sul foi avaliada pela Comissão Transatlântico Brasil I, entre novembro e dezembro de 2009. As amostras foram coletadas em 83 estações, em dois perfis entre o Brasil e África (20º e 30º Sul). Foram realizados arrastos oblíquos com rede cilindro-cônica, até 150 metros de profundidade. Observou-se uma relação sexual distinta entre as duas espécies encontradas. L. faxoni apresentou número de fêmeas significativamente maior em relação aos machos: 1:0.5 (X2 = 21,77, p = 0,0001), enquanto L. typus, teve proporção sexual de machos significativamente maior que de fêmeas: 1.86:1 (X2 = 50,84, p = 0,0001). A distribuição de L. typus variou entre as porções oeste e leste da cordilheira Mesoceânica. Essa distribuição esteve relacionada significativamente com a salinidade (R2 = 0.13; F(3.79); p = 0,009), mais elevada à oeste da área de estudo. No presente trabalho as duas espécies tiveram seus registros ampliados para o Giro Subtropical do Atlântico. De forma geral, os camarões luciferídeos foram mais frequentes e abundantes nas estações de coleta a oeste da Cordilheira Mesoceância, com L. typus sendo mais representativo tanto em abundância quanto em ocorrência.

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          Most cited references 21

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          The shelf and coastal waters off southern Brazil

          The data collected on three oceanographic cruises undertaken in 1956 indicate that the main branch of the Brazil Current flows southwards along the continental slope, where it reaches maximum velocity, and further, that a well defined limit is found between the warm and saline tropical water from the north and that situated over the central part of the shelf. This is especially the case during the summer months (October-March). Below the Brazil Current a water layer of lower salinity and temperature is found. This water mass is formed near the western extremity of the Subtropical Convergence where it sinks and flows northwards to reappear near or at the surface in an area situated between the lighter, south-flowing, tropical water, and the coastal water. Such a distribution of density across the Current is to be expected in view of the dynamics of ocean currents. There are, however, evidences which indicate the occurrence of upwelling from moderate depths, in particular near Cabo Frio where the prevailing winds from NE drive the surface waters offshore. It is further suggested that the upwelling is maintained by a thermohaline mechanism as the density of the cold and low salinity water is decreased by heating from solar radiation. In order to maintain dynamic stability, the heated water must consequently flow out of the area and be replaced by water from below which in turn suffers the same decrease of density, and so on. Such mechanism might, together with prevailing winds, be responsible for permanent or periodic upwelling near other regions in the tropical and subtropical zone of the oceans where salinity decreases with depth.
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            Ecological geography of the sea

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              Forma da correlação T-S de massas de água das regiões costeira e oceânica entre o Cabo de São Tomé (RJ) e a Ilha de São Sebastião (SP), Brasil

              As variações na estrutura e em propriedades de massas de água da plataforma continental e das de água oceânica adjacente são estudadas com base em expressões analíticas das curvas T-S, As medições das variáveis oceanográficas foram feitas por métodos clássicos numa rede de estações hidrografiacas, as quais foram amostradas em cinco intervalos de tempo (5-10 dias) cada um, entre os meses de janeiro de 1970 e fevereiro de 1971. A revisão da classificação das massas de água usada sob condições regionais confirma que as Massas de Água Subtropical Profunda (ASTP), Subtropical (AST) e Centrando Atlântico Sul (ACAS), são designações diferentes de uma mesma massa de água. A ultima nomenclatura, Água Central do Atlântico Sul (ACAS), é sugerida para indicar a massa de água com índice termohalino (20,0ºC; 36,36 ‰) , a qual e observada sob a Massa de Água Tropical. Esse valor de salinidade e um pouco maior do que o índice termohalino modificado da ACAS (36,20 ‰) e pode ser usado com vantagem nos cálculos volumétricos na área. As expressões polinomiais da curva T-S, cujos coeficientes foram determinados pelo método dos mínimos quadrados, foram usadas em aplicações práticas. Nessas aplicações, foram desenvolvidos métodos alternativos para a determinação da derivada termohalina e da razao de densidade constante (Rρ = αdT/βdS).
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                Author and article information

                Contributors
                Role: ND
                Role: ND
                Role: ND
                Journal
                bjoce
                Brazilian Journal of Oceanography
                Braz. j. oceanogr.
                Universidade de São Paulo, Instituto Oceanográfico
                1982-436X
                September 2016
                : 64
                : 3
                : 217-226
                Affiliations
                [1 ] BIOENV Meio Ambiente Brasil
                [2 ] Universidade Federal do Espírito Santo Brazil
                Article
                S1679-87592016000300217
                10.1590/S1679-87592016099006403

                This work is licensed under a Creative Commons Attribution 4.0 International License.

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                Product Information: website
                Categories
                MARINE & FRESHWATER BIOLOGY
                OCEANOGRAPHY

                Oceanography & Hydrology, Ecology

                Larva, Zooplankton, Decapods, Densidade, Zooplâncton, Decápodes, Density

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