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Caracterização das megaesponjas do batial superior dos Açores
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| Versão Corrigida | 3.7 MB | Adobe PDF |
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Abstract(s)
As esponjas constituem um grupo taxonómico importante e diverso nas comunidades bentónicas, em especial em ecossistemas de oceano profundo, onde desempenham papéis funcionais chave. Em certas regiões, exemplares de grandes dimensões (e.i. > 5 cm) formam comunidades estruturadas conhecidas como agregações de esponjas. Contudo, devido às suas características biológica e ecológicas estes habitats são vulneráveis ao impacte humano tendo, por isso, sido classificados como Ecossistemas Marinhos Vulneráveis pela CE e como espécies ou habitats ameaçados ou declínio pela OSPAR. Os Açores são conhecidos por possuírem uma fauna diversa de espongiários. O presente estudo tem como principais objetivos: a) identificar e caracterizar morfologicamente as principais espécies de megaesponjas (classe Demospongiae) presentes no batial superior (200 - 800 m) dos Açores; e b) caracterizar a distribuição de megaesponjas no monte submarino Condor. Para a análise morfológica foram usados 64 exemplares capturados acessoriamente por palangre de fundo na ZEE dos Açores (COLETA-DOP/UAç). A identificação taxonómica foi realizada através da análise de caracteres morfológicos externos e internos, estes últimos por meio de microscopia óptica. No total 21 espécies de demosponjas, representantes de sete ordens e 11 famílias foram identificadas, das quais duas - Pachastrella ovisternata e Petrosia vansoesti constituem novos registos para os Açores. Para a descrição da distribuição das megaesponjas no monte submarino Condor, 12 h de vídeo subaquático, correspondente a uma área de 7,7x10-3 km2, foram analisadas e anotadas. Um total de 4350 megaesponjas foram registadas, sendo 49% pertencentes à espécie Pheronema carpenteri e 11% correspondentes a 14 taxa identificados. Os restantes 40% correspondem a esponjas não identificadas. Seis biótopos, que incluíam megaesponjas, foram identificados. As agregações multiespecíficas dominadas por Pheronema carpenteri, encontradas a 700-825 m de profundidade, eram as que apresentavam maior densidade de esponjas enquanto as agregações de pequenas esponjas em fundo misto, encontradas aproximadamente entre 430-1100 m, revelaram ser as mais taxonomicamente diversas. A distribuição batimétrica das espécies de megaesponjas no monte submarino Condor está de acordo com o descrito na literatura, sendo possível observar dois grandes grupos: a) exemplares das famílias Axinellidae e Petrosiidae (excluindo a X. variabilis) juntamente com a N. nolintangere que se encontram a profundidades até aos 500 m; e b) espécies das famílias Azoricidae, Macandrewiidae juntamente com X. variabilis e S. pellita que são encontradas em áreas mais profundas deste monte submarino, entre os 450-1100.
ABSTRACT: Sponges constitute an important and diverse group in benthic communities, particularly in deep-sea ecosystems where they play key ecological roles. In some areas, large specimens (i.e. > 5 cm) form structured communities known as sponge aggregations. However, due to biological and ecological features, these communities are vulnerable to human impact, reason for which they were classified as Vulnerable Marine Ecosystems (VMEs) by the EC, and as threatened and/or declining species or habitats by OSPAR. The Azores archipelago is known to harbour a diverse sponge fauna, especially at bathyal depths. This study had as main goals to: a) identify and morphologically characterize the main megasponge species (class Demospongiae) of the upper bathyal zone (200 – 800 m) of the Azores; and b) analyze the distribution of megasponges in the Condor seamount. For the morphological analysis 64 specimens bycaught by bottom longlines in the Azores EEZ (COLETA-DOP/UAç) were used. Taxonomic identifications were performed from the analysis of external and internal morphological characters, the later under optical microscopy. In total, 21 demosponge species representing seven orders and 11 families were identified, of which two - Pachastrella ovisternata and Petrosia vansoesti - constitute new records for the Azores. For the description of megasponges distribution in the Condor seamount, 12h of underwater videos, corresponding to an area of 7.7x10-3 km2 were analyzed and annotated. A total of 4350 megasponges were recorded, of which 49% corresponded to the birds’ nest sponge Pheronema carpenteri and 11% corresponded to 14 identified taxa. The remainder 40% of the records corresponded to unidentified sponges. Six biotopes that included megasponges were identified. Pheronema carpenteri multispecific aggregations, found at 700-825 m depth, were the ones with the highest sponge density, whereas mixed substrates found approximately between 430-1100 m were the most taxonomically diverse. The bathymetric distribution of the megasponge species found in the Condor seamount were within the ranges reported in the literature and two main groups are distinguished on the basis of their vertical range: a) species within the families Axinellidae and Petrosiidae (excluding X. variabilis) along with N. nolitangere were found down to 500 m depth; and b) species within the Azoricidae, Macandrewiidae and the species X. variabilis and S. pellita were found in the deeper areas of this seamount, between 450-1100 m depth.
ABSTRACT: Sponges constitute an important and diverse group in benthic communities, particularly in deep-sea ecosystems where they play key ecological roles. In some areas, large specimens (i.e. > 5 cm) form structured communities known as sponge aggregations. However, due to biological and ecological features, these communities are vulnerable to human impact, reason for which they were classified as Vulnerable Marine Ecosystems (VMEs) by the EC, and as threatened and/or declining species or habitats by OSPAR. The Azores archipelago is known to harbour a diverse sponge fauna, especially at bathyal depths. This study had as main goals to: a) identify and morphologically characterize the main megasponge species (class Demospongiae) of the upper bathyal zone (200 – 800 m) of the Azores; and b) analyze the distribution of megasponges in the Condor seamount. For the morphological analysis 64 specimens bycaught by bottom longlines in the Azores EEZ (COLETA-DOP/UAç) were used. Taxonomic identifications were performed from the analysis of external and internal morphological characters, the later under optical microscopy. In total, 21 demosponge species representing seven orders and 11 families were identified, of which two - Pachastrella ovisternata and Petrosia vansoesti - constitute new records for the Azores. For the description of megasponges distribution in the Condor seamount, 12h of underwater videos, corresponding to an area of 7.7x10-3 km2 were analyzed and annotated. A total of 4350 megasponges were recorded, of which 49% corresponded to the birds’ nest sponge Pheronema carpenteri and 11% corresponded to 14 identified taxa. The remainder 40% of the records corresponded to unidentified sponges. Six biotopes that included megasponges were identified. Pheronema carpenteri multispecific aggregations, found at 700-825 m depth, were the ones with the highest sponge density, whereas mixed substrates found approximately between 430-1100 m were the most taxonomically diverse. The bathymetric distribution of the megasponge species found in the Condor seamount were within the ranges reported in the literature and two main groups are distinguished on the basis of their vertical range: a) species within the families Axinellidae and Petrosiidae (excluding X. variabilis) along with N. nolitangere were found down to 500 m depth; and b) species within the Azoricidae, Macandrewiidae and the species X. variabilis and S. pellita were found in the deeper areas of this seamount, between 450-1100 m depth.
Description
Dissertação de Mestrado, Estudos Integrados dos Oceanos, 19 de Julho 2013, Universidade dos Açores.
Keywords
Batial Superior Esponja Megaesponjas Monte Submarino Condor Açores Porifera Sponge Megasponge Upper Bathyal Azores
Citation
Pereira, Raquel Sofia Macedo. "Caracterização das megaesponjas do batial superior dos Açores". 2013. 123 p.. (Dissertação de Mestrado em Estudos Integrados dos Oceanos) - Horta: Universidade dos Açores, 2013.