UCN-CEAZA
Floating Seaweeds and Their Communities.
Rothäusler, E., Gutow, L., & Thiel, M.
A wide diversity of floating seaweeds is found in temperate and subpolar regions of the world’s oceans where sea surface currents and winds determine their traveling velocities and directions. The importance of floating seaweeds as dispersal agents for associated organisms and for the algae themselves varies depending on the supply from benthic source populations and on their persistence at the sea surface. Persistence of floating algae depends on water temperature, grazing activity, epifaunal load, and, to a lesser extent, on prevailing irradiance conditions. In temperate regions, persistence of floating algae is primarily limited by warm sea surface temperatures and high densities of motile and sessile epifauna whereas at higher latitudes algae can successfully compensate grazer-induced tissue loss by continuous growth at the prevailing low water temperatures. Accordingly, floating seaweeds can bridge large oceanic distances especially at high latitudes allowing for connectivity among distant benthic populations of algae and associated rafters.
Año: 2012
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Referencia APA: Rothäusler, E., Gutow, L., & Thiel, M. (2012). Floating Seaweeds and Their Communities. Ecological Studies, 359-380.
Authentication of commercialized crab-meat in Chile using DNA Barcoding.
Haye, P., Segovia, N., Vera, R., Gallardo, M., & Gallardo-Escárate, C.
Authentication of commercialized marine products has become a market priority. Crustaceans are benthic marine resources highly exploited in Chile. Brachyuran crabs are of particular interest and in Chile are commercialized with different processing and presentations. Generally, Chilean brachyuran crab-meat commercial packages do not include taxonomic information, which in addition to the loss of diagnostic characters during the processing, impedes the identification of species being commercialized. The goal of this study was to determine which brachyuran species are being commercialized in the Chilean market using DNA Barcoding and phylogenetic analysis. For authentication of commercial crab-meat and DNA Barcoding a partial sequence of the Cytochrome Oxidase I (COI) gene of seven commercialized brachyuran species in Chile were used. For authentication, samples were obtained from seven commercial formats available on the local market in Coquimbo, Chile. Most commercial packages contained more than one species of crab. The Species detected in order of frequency are Metacarcinus edwardsii, Romaleon polyodon, Cancer porteri, Cancer plebejus, and Homalaspis plana. Mislabeling was detected in one of the commercial formats that declared including meat from Cancer species. The procedure presented herein, based on standard DNA Barcoding as well as phylogenetic analyses, can be used for the normative control of crab-meat processed products.
Año: 2012
Palabras claves: Food authentication; DNA Barcoding; Crab meat; Species identification; Mislabeling; Conservation genetics
Referencia APA: Haye, P., Segovia, N., Vera, R., Gallardo, M., & Gallardo-Escárate, C. (2012). Authentication of commercialized crab-meat in Chile using DNA Barcoding. Food Control, 25(1), 239-244.
Genetic signatures of rafting dispersal in algal-dwelling brooders Limnoria spp. (Isopoda) along the SE Pacific (Chile).
Haye, P., Varela, A., & Thiel, M.
ABSTRACT: Brooding marine isopods of the genus Limnoria inhabit and feed on kelp holdfasts and wood. These substrata have high floating potential, making these species ideal organisms to study the effects of rafting-mediated connectivity on the population structure of brooders living on rafting substrata. It is hypothesized that rafting leaves particular genetic signatures such as low differentiation among distant local populations and absence of isolation by distance (IBD) at a macro-geographic scale (thousands of km). Using cytochrome oxidase I (COI) sequences, we tested the effects of rafting-mediated gene flow with respect to genetic differentiation on L. quadripunctata (from wood and also the holdfasts of the giant kelp Macrocystis pyrifera) and L. chilensis (mainly from the bull kelp Durvillaea antarctica) sampled across 2400 km of the Chilean coast. Analyses of COI data for both species indicated low differentiation between distant locations along the Chilean coast and lack of IBD, bearing the expected genetic signatures of rafting dispersal. Phylogenetic analyses were performed with COI and the nuclear gene 28S to place the genetic diversity of Chilean Limnoria spp. into a wider geographical context. Both markers revealed that L. quadripunctata from Chile is a sister clade to other Limnoria spp. analyzed (L. chilensis, L. segnis, and L. stephenseni), which mainly inhabit D. antarctica. L. chilensis from Chile and subantarctic islands form a tight monophyletic group. Phylogenetic and phylogeographic analyses show that along the studied area, L. quadripunctata and L. chilensis have the genetic signatures of relatively recent or ongoing rafting.
Año: 2012
Palabras claves: Peracarids, Rafting, Biogeography, Mitochondrial DNA, COI, 28S, Phylogeny, Phylogeography
Referencia APA: Haye, P., Varela, A., & Thiel, M. (2012). Genetic signatures of rafting dispersal in algal-dwelling brooders Limnoria spp. (Isopoda) along the SE Pacific (Chile). Marine Ecology Progress Series, 455, 111-122.