Pelagic Biodiversity and Biogeography around the SouthAmerican continent

Abstract

Biogeography around South America is well documented on the Atlantic side and less well documented on the Pacific side especially south of about 30º S. The South Pacific oceanic areas are the least known of all pelagic areas. The different approaches to determine biogeographic provinces (e.g. the classical one showing mainly latitudinal and watermass distribution patterns based on presence/absence of species; and the biogeochemical approach based on productivity regimes and modelling) are discussed. The latter shows more east-west division. Testing of these concepts will probably reveal more coastal provinces in the Pacific area. The transitional area in the South Pacific is also an interesting area for molecular species research because there are some joint species with the Atlantic Ocean species that are not often found in the southern Indian Ocean.KEYWORDS: Pelagic biodiversity, biogeography, South America. RESUMENLa biogeografía en torno de América del Sur está bien documentada en el lado Atlántico y menos documentada en el Pacífico, especialmente al sur de los 30º S. Las áreas oceánicas del Pacífico Sur son las menos conocidas de todas las áreas pelágicas. Se discute los diversos intentos para determinar las provincias biogeográficas, e.g. el clásico que muestra los principales patrones de distribución latitudinal y de masas de agua basados en la presencia/ausencia de especies, y del método biogeoquímico basado en regímenes de productividad y modelamiento. El último muestra una división más este-oeste. La prueba de estos conceptos revelará probablemente más provincias costeras en el área del Pacífico. El área de transición en el Pacífico Sur, también es un área interesante para la investigación molecular de las especies porque hay un número de especies comunes con el Océano Atlántico, especies que no se presentan a menudo en el Océano Índico del Sur.

Siphonophores from surface waters of the Colombian Pacific Ocean

“…All species found in our study are epipelagic (Mackie et al, 1988;Mapstone, 2014) and perform vertical migration (Pugh, 1984;Mackie et al, 1988), which explains the higher richness we found at night. Consistent with the idea that there is a peak in siphonophore richness in subtropical/tropical waters (Mackie et al, 1988;Boltovskoy, 1999;Macpherson, 2002;Pierrot-Bults & Angel, 2013), we found more species (21 species) than in temperate waters such as off Chile (16 species, Palma, 1999) and in the Mediterranean Sea (12 species, Thibault-Botha et al, 2013).…”

“…By comparison with the rest of the planktonic environment, the hyponeuston is poorly known and yet it provides an important habitat for early life history stages of fishes (Banse, 1964;Ahlstrom & Stevens, 1976;Jeong et al, 2014), whose abundances may be impacted by siphonophores (Purcell, 1985). Here we provide new insights into the poorly known hyponeuston of the tropics, which are some of the most biodiverse areas of the world (Roy et al, 1998;Boltovskoy, 1999;Harris et al, 2000;Macpherson, 2002;Pierrot-Bults & Angel, 2013). We investigate siphonophore diversity within the hyponeuston for two major orders of siphonophores (Calycophorans and Physonects) and its relation to environmental variables.…”

Uncovering the Composition and Diversity of Pelagic Copepods in the Oligotrophic Blue Water of the South Pacific Subtropical Gyre

“…Our findings indeed showed that diversity is higher in the SPSG compared to the highly productive coastal zone of Chile (Hidalgo et al, 2010;Pino-Pinuer et al, 2014), indicating an inverse relationship between diversity and biological productivity at least within basins, as suggested by previous authors (Margalef, 1969;Venrick, 1982;Irigoien et al, 2004). High diversity in oligotrophic waters is also a characteristic of microzooplankton (Pierrot-Bults, 2003). The abundance and diversity found in this study were lower than in other studies conducted in oligotrophic areas (McGowan and Walker, 1979;Piontkovski et al, 2003;Vereshchaka et al, 2017), although comparisons with other studies is difficult due to variable sampling efforts and the dependence of the Shannon-Wiener diversity index on sample size and the type of logarithm used for its calculation (Gray, 2000).…”

Connectivity Between Coastal and Oceanic Zooplankton From Rio Grande do Norte in the Tropical Western Atlantic

“…results in circumglobal distribution patterns. This occurs much more commonly than endemism for pelagial plankton (Boltovskoy et al, 2002;Pierrot-Bults and Angel, 2012). Species with high proportions of neritic organisms and benthopelagic forms are excluded from this pattern (Angel, 1993).…”