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Published on: August 17, 2016
The effect of sediment mimicking drill cuttings on deep water rhodoliths in a flow-through system: Experimental work
Marcia A O Figueiredo1, Ingvar Eide2, Marcia Reynier3
1Instituto de Pesquisa Jardim Botânico do Rio de Janeiro, Rua Pacheco Leão 915, Jardim Botânico 22460-030, Rio de Janeiro, RJ, Brazil; Instituto Biodiversidade Marinha, Avenida Ayrton Senna 250, Sala 208, Barra da Tijuca, 22793-000, Rio de Janeiro, RJ, Brazil; Instituto de Estudos do Mar Almirante Paulo Moreira, Departamento de Oceanografia, Divisão de Biotecnologia Marinha, Rua Kioto 253, 28930-000, Arraial do Cabo, RJ, Brazil.
Abstract:
The impact of sediment coverage on two rhodolith-forming calcareous algae species collected at 100m water depth off the coast of Brazil was studied in an experimental flow-through system. Natural sediment mimicking drill cuttings with respect to size distribution was used. Sediment coverage and photosynthetic efficiency (maximum quantum yield of charge separation in photosystem II, ϕPSIImax) were measured as functions of light intensity, flow rate and added amount of sediment once a week for nine weeks. Statistical experimental design and multivariate data analysis provided statistically significant regression models which subsequently were used to establish exposure-response relationship for photosynthetic efficiency as function of sediment coverage. For example, at 70% sediment coverage the photosynthetic efficiency was reduced 50% after 1-2weeks of exposure, most likely due to reduced gas exchange. The exposure-response relationship can be used to establish threshold levels and impact categories for environmental monitoring.
