Sroczynska, KatarzynaBarroso, GilbertoChícharo, Luís2014-09-222014-09-222012Sroczynska, Katarzyna; Barroso, Gilberto; Chícharo, Luís. In situ effective clearance rate measurement of mangrove oysters (Crassostrea rhizophorae) in a tropical estuary in Brazil, Ecohydrology & Hydrobiology, 12, 4, 301-310, 2012.1642-3593AUT: LCH00360http://hdl.handle.net/10400.1/5041Anthropogenic nutrient enrichment in estuaries induces high phytoplankton production, contributing to coastal eutrophication. Abundant natural banks of filter feeders, such as bivalves, in downstream areas may contribute to reducing symptoms of eutrophication by decreasing phytoplankton biomass and amount of material subjected to microbial regeneration. The current concern is to what extent bivalves can control water quality and how environmental parameters can influence the filtration process and vice versa. In the present study Crassostrea rhizophorae (Guilding, 1818) grazing ability on suspended particles in their natural environment was determined in situ, using the biodeposition method and uniquely constructed sediment traps. Additionally the effect of body size on effective clearance rate (ECR) was examined using three different size groups. The experiment was conducted in the Piraquê-açu/Piraquê-mirim estuary system, (Aracruz, ES, Brazil) during the second week of June 2012 (dry season). Environmental parameters were measured together with total particulate matter (TPM, mg L-1) and chlorophyll a analysis (CHL, μg L-1) at the beginning and at the end of the experiment. Average values recorded for TPM and CHL were 5.79 mg L-1 and 2.55 μg L-1 respectively with very high organic seston fraction (80%). The reported effective clearance rate (ECR, in litres per hour) was 17.99 L h-1g-1 dry weight (DW), one of the highest reported in literature and can be associated with a high detritus content and different feeding strategies in comparison to bivalves residing in temperate environments. Weight and length (height) relationship were closely correlated (r = 0.73) however, clearance rate (ECR) standardized to 1 g dry tissue weight did not vary significantly among different size classes. High ECR at high particulate organic matter (POM, %) supports the belief that bivalves can exhibit ECR flexibility according to food quality.porCrassostreaEffective clearance rateNatural sestonOyster sizeTropical ecosystemjournal article2014-09-19http://dx.doi.org/10.2478/v10104-012-0024-0