Marine biodiversity: an exploration of São Paulo coastal islands using environmental DNA metabarcoding

Abstract

Biological diversity is an ecosystem property that has received increasing attention in recent years, mainly because biodiversity loss is one of the most critical current environmental problems. Specifically, marine biodiversity may be subject to rapid changes due to anthropogenic influences such as fishing, oil and gas exploration, nonindigenous species introduction, environmental destruction, and climate change. To gather data to support future monitoring plans, mainly in depauperate populations and remote ecosystems, the development of non-invasive techniques that minimize the risks of injury or death of animals is imperative. Biodiversity surveys using DNA derived from environmental samples, known as "environmental DNA" (eDNA), allow the detection of traces of genetic material of cellular or extracellular form released into the environment through mucus, excrements, gametes, skin cells, and decomposing carcasses of different organisms. Environmental DNA can be retrieved from the environment, amplified, sequenced, and taxonomically assigned using high-throughput sequencing (HTS) metabarcoding. Despite being a widely used, rapid and efficient biodiversity monitoring tool in temperate regions, eDNA metabarcoding has not been used yet to assess the Brazilian marine biodiversity. Therefore, this pioneering project proposal will work towards filling the knowledge gap concerning marine biodiversity of protected and unprotected ecosystems via eDNA metabarcoding. Specifically, we will use massive sequence data to provide a better understanding of the current marine eukaryotic biodiversity at community (high taxonomic levels - phylum) and assemblages of fish, porifera and anthozoa at species-specific level, testing hypotheses about the possible causes of biodiversity changes. Biomonitoring data that will be performed over two years within four geographic regions in the São Paulo state, including Laje de Santos Marine State Park, Alcatrazes Archipelago Wildlife Refuge, Queimada Grande Island, and Búzios Island. Hypotheses will be tested to examine wheter eukaryotic community and some metazoan taxa (porifera, anthozoan, and fish) identified through eDNA metabarcoding differ among the various regions and the two collection years. We will compare oceanographic conditions within the two sampling years to correlate different environmental conditions with biodiversity patterns. Therefore, this project will provide crucial lacking information about marine biodiversity, which will be disseminated to both scientists and policy managers, contributing to better conservation management actions of the marine realm. By the end of this project, we expect to have contributed to a better knowledge of São Paulo marine biodiversity, implemented a new research line at the Oceanographic Institute, University of São Paulo (USP), and trained researchers and students in different disciplines such as genomics, oceanography, marine molecular ecology, evolution, bioinformatics, and statistical analysis. (AU)