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Ocorrência de plásticos no tubo digestivo do Calca-mar (pelagodroma marina hypoleuca) das Ilhas Selvagens : Potencialidades para a monitorização da poluição no mar português?
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Abstract(s)
A poluição marinha por plástico, é um dos maiores problemas ambientais que afeta os ecossistemas marinhos, na atualidade. Esta investigação teve como objetivos avaliar a prevalência de plástico e caracterizar o conteúdo plástico ingerido por uma ave pelágica, o Calca-mar, durante o período de 2012- 2014. Foram analisadas 313 plumadas que continham Calca-mares, das Ilhas Selvagens. O presente estudo documenta uma incidência de 70% de plásticos em Calca-mares, provenientes de plumadas de Gaivotas-de-Patas-Amarelas (Larus michahellis). Foram recolhidos 1061 pedaços de plástico, com um peso total de 4,701g. No total, 91,5% das partículas analisadas mediam entre 0,46 e 5,0 milímetros. O tipo de plástico mais abundante foi o plástico de utilizador (83,6 %). Em termos de cores, a análise revelou que os plásticos de cor clara (68,0 %) foram predominantes, seguidos dos de cores intermédias (16,0 %) e escuras (16,0%). O tipo de polímero mais ingerido foi o HDPE (70,0%). Procurou analisar-se se a probabilidade de ingestão de plásticos variava, entre indivíduos, em função das características do seu nicho trófico e isotópico. Assim, comparou-se a composição em isótopos estáveis de carbono e azoto das unhas de Calca-mares que haviam ingerido plástico com outros que não tinham ingerido. Foi constatado que não existem diferenças: indivíduos com plástico (N: 10,74 ‰ ± 0,49‰; C: -19,12 ‰ ± 0,52‰) e indivíduos sem plástico (N: 10,70 ‰ ± 0,54‰; C: 19,00 ‰ ± 0,64‰). Este estudo confirma o potencial das plumadas como bioindicadores para a poluição marinha.
ABSTRACT: Nowadays, the marine pollution caused by plastics is one of the biggest environmental problems which affect marine ecosystems. This investigation intended to evaluate the prevalence of plastic and to characterize plastic content ingested by a pelagic bird, the Calcamar, in the period 2012-2014, sampled at the Selvagens Islands Nature Reserve. We analysed 313 pellets from Yellow-legged gulls (Larus michahellis) containing Calcamares and 70.0% of these contained plastic remains originating in the digestive tract of the preyed birds. We collected 1061 plastic pieces with a total weight of 4.701g. In total, 91.5% of the analysed particles measured from 0.46 to 5.0 mm. The predominant type of plastic was the user plastic (83.6%). Considering the colours, the analysis revealed that light coloured plastics are predominant (68.0%), followed by intermediate colours (16.0%) and dark ones (16.0%) The most ingested type of polymer was the HDPE (70.0%). This study also attempted to analyse if the probability of plastic ingestion varied, amongst individuals, according to the characteristics of their trophic and isotopic niche. The composition in stable isotopes of carbon and nitrogen present in the toenails of Calcamares that had ingested plastics was compared to the ones of individuals that had no plastic in their guts. We observed no differences: individuals with plastic (N: 10.74 ‰ ± 0.49‰; C: -19.12 ‰ ± 0.52‰) and individuals without plastic (N: 10.70 ‰ ± 0.54‰; C: 19.00 ‰ ± 0.64‰). This study confirms the potential of the pellets as bio-indicators for marine pollution.
ABSTRACT: Nowadays, the marine pollution caused by plastics is one of the biggest environmental problems which affect marine ecosystems. This investigation intended to evaluate the prevalence of plastic and to characterize plastic content ingested by a pelagic bird, the Calcamar, in the period 2012-2014, sampled at the Selvagens Islands Nature Reserve. We analysed 313 pellets from Yellow-legged gulls (Larus michahellis) containing Calcamares and 70.0% of these contained plastic remains originating in the digestive tract of the preyed birds. We collected 1061 plastic pieces with a total weight of 4.701g. In total, 91.5% of the analysed particles measured from 0.46 to 5.0 mm. The predominant type of plastic was the user plastic (83.6%). Considering the colours, the analysis revealed that light coloured plastics are predominant (68.0%), followed by intermediate colours (16.0%) and dark ones (16.0%) The most ingested type of polymer was the HDPE (70.0%). This study also attempted to analyse if the probability of plastic ingestion varied, amongst individuals, according to the characteristics of their trophic and isotopic niche. The composition in stable isotopes of carbon and nitrogen present in the toenails of Calcamares that had ingested plastics was compared to the ones of individuals that had no plastic in their guts. We observed no differences: individuals with plastic (N: 10.74 ‰ ± 0.49‰; C: -19.12 ‰ ± 0.52‰) and individuals without plastic (N: 10.70 ‰ ± 0.54‰; C: 19.00 ‰ ± 0.64‰). This study confirms the potential of the pellets as bio-indicators for marine pollution.
Description
Dissertação de Mestrado apresentada ao ISPA - Instituto Universitário
Keywords
Ingestão Plástico Plumadas Ingestion Plastic Pellets