|Titre||Marine geodiversity of northeastern Brazil: a step towards benthic habitat mapping in Pernambuco Continental Shelf|
|Télécharger||Téléchargement (publication entière) |
|Licence||Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures.|
|Auteur||Lucatelli, D; Camargo, J M R; Brown, C J; Souza-Filho, J F; Guedes-Silva, E; Araújo, T C M|
|Source||Program and abstracts: 2017 GeoHab Conference, Dartmouth, Nova Scotia, Canada; par Todd, B J; Brown, C J; Lacharité, M; Gazzola, V; McCormack, E; Commission géologique du Canada, Dossier public 8295, 2017 p. 81, https://doi.org/10.4095/305889 Accès ouvert|
|Liens||GeoHab 2017 |
|Éditeur||Ressources naturelles Canada|
|Réunion||2017 GeoHab: Marine Geological and Biological Habitat Mapping; Dartmouth, NS; CA; mai 1-4, 2017|
|Media||en ligne; numérique|
|Référence reliée||Cette publication est contenue dans Program and
abstracts: 2017 GeoHab Conference, Dartmouth, Nova Scotia, Canada |
|Lat/Long OENS|| -35.0000 -33.0000 -7.0000 -10.0000|
|Sujets||techniques de cartographie; océanographie; milieux marins; études côtières; conservation; organismes marins; écologie marine; gestion des ressources; peuplements biologiques; etudes de l'environnement;
écosystèmes; marges continentales; plate-forme continentale; talus continental; benthos; sédiments marins; topographie du fond océanique; configurations lit; textures; structures sédimentaires; bathymétrie; Biologie; géologie marine; géologie des
dépôts meubles/géomorphologie; géologie de l'environnement; géophysique|
|Programme||Géoscience en mer|
|Diffusé||2017 09 26|
|Résumé||(disponible en anglais seulement)|
The Northeastern Brazil Continental Shelf (NEBCS) is one of the largest shelves off the Brazilian coast, and it is strongly influenced by volcanic and tectonic
processes. It can be divided in three portions: Inner shelf (limited by 20 m isobaths), Mid-shelf (from 20 to 40 m depth), and Outer shelf (beyond 40 m depth). Pernambuco is one of the nine States from the Northeast region of Brazil, comprising a
coast line of 187 Km (from 07°37.71'S to 08°54.34'S) and an average width of 33.28 Km. The littoral zone is strongly influenced by urban development, with extreme pollution in some areas, particularly near the capital Recife and the metropolitan
region. Nevertheless, there are two Marine Protected Area (MPA) included in the Pernambuco EEZ, namely "Fernando de Noronha Archipelago" and "APA Costa dos Corais". However, there have been no habitat mapping studies within this region of the
continental shelf, and only a small number along Brazilian coast. Based on the limited information available, the present work aimed to initiate the compilation of existing seafloor data sets on the Pernambuco region. The main objective was to map
the physiography and relate it with the classes of sediment, providing a map of the geodiversity from the coast of Pernambuco (from inner to outer shelf).
To achieve the objectives of the study, abiotic data available in a public database, and
results of technical-scientific surveys from the area were explored. Specifically, topography, slope, and sedimentary texture data were integrated. The topography was based on Gorini (1996). The map curvature was generated on ArcMap 10.1 software.
Folks' classes were used to classify the sediment and stations were interpolated by natural neighbor. To improve the information for the locality, data from the Brazilian National Oceanographic Data Bank (BNDO) was added. Thus, a total of 314 samples
were accomplished for the analyses. Multidimensional and PCA analyses were conducted using PRIMER 6.
Results of bathymetric analysis suggested some considerations: Inner and Outer shelf are narrow in the south and broaden northward along the
shelf. On the other hand, the Mid-shelf is a broad southward and narrow at North portion. The slope is variable, being possible to observe several long portions with low degree (0.8-1°) of steepness along the Inner shelf. The presence of steps toward
Mid-shelf could be observed as well. A flat portion is registered at the southern part of the shelf. Irregular areas are shown toward North. Pernambuco's platform presents its edge between 55-65 m, revealing an extended stability of the continental
shelf, in terms of tectonic and sedimentary processes. The abrupt gradient variation of the shelf edge is clearly marked, as well as the strong steepness on superior slope. Additionally, the MDS and PCA analyses reflect the influence of terrigenous
sediment, coming from continental region for the Inner shelf, and the presence of calcareous algae plus organogenic fragments (from beach-rocks and corals) on the mid and outer shelf. The sediment composition is highly relevant to the benthos
distribution. Based on our results a texture map was constructed showing the general pattern for the sediment distribution along the shelf of Pernambuco.
|Sommaire||(Résumé en langage clair et simple, non publié)|
La seizième conférence annuelle GeoHab s'est déroulée cette année (2017) au campus Waterfront du Nova Scotia Community College à Dartmouth, en
Nouvelle-Écosse, au Canada.