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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Sinking particles in the photic zone: relations with biogeochemical properties in different sectors of the Cananéia-Iguape Estuarine-Lagoon Complex (CIELC)-Brazil

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Author(s):
Bruno O. Sutti [1] ; Vitor G. Chiozzini [2] ; Carmen G. Castro [3] ; Elisabete S. Braga [4]
Total Authors: 4
Affiliation:
[1] University of São Paulo. LABNUT-IOUSP Institute of Oceanography. Laboratory of Biogeochemistry of Nutrients, Micronutrients and Traces in Oceans - Brasil
[2] University of São Paulo. LABNUT-IOUSP Institute of Oceanography. Laboratory of Biogeochemistry of Nutrients, Micronutrients and Traces in Oceans - Brasil
[3] Instituto de Investigaciones Marinas - Espanha
[4] University of São Paulo. LABNUT-IOUSP Institute of Oceanography. Laboratory of Biogeochemistry of Nutrients, Micronutrients and Traces in Oceans - Brasil
Total Affiliations: 4
Document type: Journal article
Source: Ocean and Coastal Research; v. 71, 2023-11-13.
Abstract

Abstract Over the last decades, regional climate changes, erosion, and heightened agricultural runoffs have increased nutrient and particle input in rivers, unbalancing the biogeochemical cycle of this suspended material along estuaries. In this context, particle fluxes in the euphotic zone, a very productive layer and important to maintain the food chain and estuarine preservation, require better understanding. This study aims to evaluate particle sedimentation fluxes in the photic zone of the Cananéia-Iguape Estuarine-Lagoon Complex (CIELC), considering sectors under different salinities and trophic statuses. A cylindrical sediment trap was installed at the base of the photic layer to measure particle fluxes and photopigments. Meanwhile, water samples were taken to measure temperature, salinity, pH, dissolved oxygen, and nutrients. Valo Grande (a freshwater domain) showed high nutrient concentrations, in which high fluxes of phaeopigments and chlorophyll-b highlighted the contribution of vegetable detritus to particle sinking. In the Batatais mangrove creek, the high fluxes of organic particles (675.32 mg m-2 d-1) and chlorophyll-a (98.40 mg m-2 d-1) evinced a high contribution of microplankton to carbon sinking. During the winter of 2018, flocculation processes were evinced in the flood tide of the Cananéia Bay as an important driver of sedimentation rates, with considerable fluxes of inorganic particles (1161.20 mg m-2 d-1) and chlorophyll-a (83.27 mg m-2 d-1). In the summer of 2019, we observed a lower flux in total particles (451.24 mg m-2 d-1) in a period of haline stratification. In the Ararapira Channel, the lowest organic particle fluxes (<100 mg m-2 d-1) were associated with ultra-oligotrophic conditions, indicating a low influence of microplankton on sinking particles. These findings suggest that freshwater input, tidal variation, and trophic status are relevant controls of sinking particles in different CIELC sectors. (AU)

FAPESP's process: 20/16485-7 - Biogeochemical and socio-environmental study of coastal ecosystems: contribution to the assessment of sustainability and environmental impact (BIOGEOQUIS-ECOS)
Grantee:Elisabete de Santis Braga da Graça Saraiva
Support Opportunities: Regular Research Grants