ARTICLE IN PRESS JID: ECOHYD [m3Gdc;May 1, 2020;14:27] Ecohydrology & Hydrobiology xxx (xxxx) xxx Contents lists available at ScienceDirect Ecohydrology & Hydrobiology journal homepage: www.elsevier.com/locate/ecohyd Original Research Article Removal of seston by crassostrea rhizophorae (guilding, 1828) in the vitoria bay estuarine system, brazil Thayana de Alencar Leite a , Gilberto Fonseca Barroso b , Q1 Mônica Maria Pereira Tognella c , Sávia Soares Pascoalini a , Luis Chicharo d a Environmental Oceanography Graduate Program, Federal University of Espirito Santo, Vitória, ES, Brazil b Department of Oceanography and Ecology, Federal University of Espirito Santo, Vitória, ES, Brazil c Department of Biological Sciences, Federal University of Espirito Santo, Vitória, ES, Brazil d Faculty of Science and Technology, University of Algarve, Faro, Portugal a r t i c l e i n f o Article history: Received 6 December 2017 Revised 22 November 2019 Accepted 21 March 2020 Available online xxx Key words: Ecohydrology Oyster Bivalve Clearance rate Salinity Estuarine ecosystem a b s t r a c t The clearance of organic suspended particles by bivalve mollusks in estuarine ecosystems has been considered a key regulating service. In Neotropical estuaries and associated man- grove ecosystems, the mangrove oyster, Crassostrea rhizophorae, is a key species in such process. To evaluate C. rhizophorae clearance rates (CR bd ), biodeposit experiments were carried out at dry (2015) and wet (2016) seasons, in three sites of the Vitória Bay Estu- arine System (VBES), southeastern Brazil. The average CR bd was 0.67 L.g −1 .h −1 , which can be regarded as low CR. Although organic fraction predominate in the particulate matter (>60%), estuarine high salinity caused by low river discharge during prolonged regional drought, impaired oyster feeder rates. When the CR bd take in account the estimate entire mangrove oyster biomass at the VBES (3.77 × 10 5 kg.km −2 ) it yields a rate of 6.51 × 10 6 m 3 .kg −1 .day −1 , corresponding to a mean daily capacity of organic seston removal of 26% of the total estuarine volume. Even conservative, this result highlight the importance of man- grove oyster for the estuarine regulation, emphasizing its ecological importance and the needs to sustain the key ecosystem services of regulating estuarine environmental quality. © 2020 European Regional Centre for Ecohydrology of the Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved. 1. Introduction 1 Suspended particles in water column, also known as 2 seston, are key structural components of aquatic ecosys- 3 tems, regulating water clarity and the depth of the photic 4 zone, therefore primary and secondary production. Ses- 5 ton comprises organic and inorganic particles greater than 6 0,45 μm with decaying of detrital matter fractions, plank- 7 ton, nutrients, silt, clay and associated pollutants. Sedimen- 8 tation, resuspension, mixing, mineralization and retention 9 E-mail addresses: thay.oceanografia@gmail.com (T. de Alencar Leite), gilberto.barroso@ufes.br (G.F. Barroso), monica.tognella@gmail.com (M.M.P. Tognella), savia.pascoalini@gmail.com (S.S. Pascoalini), lchichar@ualg.pt (L. Chicharo). are key processes of aquatic ecosystem functioning regulat- 10 ing the dynamics of suspended particles (Håkanson, 2006). 11 Marine and estuarine bivalve mollusks, such as oysters, can 12 regulate the quantity and quality of suspended particles re- 13 moving phytoplankton through filter feeding (Dame, 1996; 14 Pomeroy et al., 2006; Newell et al., 2007; Lens and Boehs, 15 2011; Sroczy ´ nska et al., 2012; Pollack et al., 2013). Q2 16 The estuarine variability inherent in longitudinal and 17 vertical physicochemical gradients requires a great phys- 18 iological plasticity of biological species to stand the dy- 19 namic environment of salinity, dissolved oxygen, turbid- 20 ity and amount of suspended particles. In neotropical es- 21 tuaries and associated mangrove ecosystems the mangrove 22 oyster, Crassostrea rhizophorae, which grows in an intertidal 23 zone attached to the root systems of the red mangrove, 24 https://doi.org/10.1016/j.ecohyd.2020.03.003 1642-3593/© 2020 European Regional Centre for Ecohydrology of the Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved. Please cite this article as: T. de Alencar Leite, G.F. Barroso and M.M.P. Tognella et al., Removal of seston by crassostrea rhizophorae (guilding, 1828) in the vitoria bay estuarine system, brazil, Ecohydrology & Hydrobiology, https: //doi.org/10.1016/j.ecohyd.2020.03.003