Metacommunity: spatial and temporal dynamics of Capitellidae annelids in submarine canyons

Author(s)

José Weverton Santos de Souza

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2024-01-16

Examining board members

Antonia Cecília Zacagnini Amaral; Silvio Felipe Barbosa de Lima; Wagner Ferreira Magalhães; Fosca Pedini Pereira Leite; Maikon Di Domenico

• Advisor: Antonia Cecília Zacagnini Amaral; Helio Herminio Checon

Abstract

Submarine canyons are complex geomorphological formations, and their presence promotes an increase in the heterogeneity of the continental margin. This complexity has a direct impact on the spatio-temporal faunal distribution, varying according to the spatial scale analyzed. In this context, we investigated the assembly of the "Capitellidae" (Annelida) metacommunity in submarine canyons during two seasonal periods. The thesis is divided into three chapters. Chapter 1: We discuss the effects of the intrusion of four water masses on environmental heterogeneity and diversity metrics. We evidenced the occurrence of masses of Tropical Water, Central Water of the South Atlantic, Intermediate Antarctic Water and Deep Water of the North Atlantic. The occurrence of these water masses promoted vertical environmental stratification and increased environmental heterogeneity. We recorded high rates of beta-diversity promoted by turnover and species sorting. The highest rates of beta-diversity occurred in deep waters. The intrusion of water masses rich in O2 had a negative effect on richness, abundance and diversity. These results suggest that water masses generate a strong environmental gradient capable of selecting sets of local species and that O2 is a secondary and non-limiting factor for these communities, since increases in abundance, richness and diversity were strongly related to temperature and salinity. Chapter 2: we address the influence of spatial scales on the perception of environmental and biological patterns in different seasonal periods. We found an increase in environmental heterogeneity associated with increasing spatial scale. Furthermore, our results indicated the influence of neutral and niche processes on the beta-diversity of "Capitellidae" annelids and that the spatial scale analyzed directly influences the observed patterns and is dependent on the characteristics of each system, in which the environmental component was almost always most important for assembling these communities, especially on a larger spatial scale. Chapter 3: we investigated the bathymetric spatial niche overlap and within sediment layers as a strategy for species coexistence under different environmental conditions. We found that species present restrictions along environmental gradients, and this reflected low niche amplitude in both canyons and seasonal periods. Furthermore, we found that large sets of species overlap in the use of bathymetric space and segregate their distribution vertically in the sediment layers as a strategy for coexistence and reducing possible competitive interactions. The reduction of organic nutrients along the bathymetric gradient promoted a reduction in the use of sediment layers and a decline in richness and density. These patterns highlight the existence of niche sharing and differentiation processes in bathymetric gradients and sediment layers and the influence of nutrient availability mediating the assembly of these communities. We believe that these results contribute significantly to environmental and biological knowledge in the deep sea, especially in submarine canyons, due to their high complexity and because they are little explored. Furthermore, these environments can be considered potential hotspots of diversity, therefore, these data can be fundamental to guide the adequate establishment of Marine Protected Areas aiming at the conservation of these unique environments (AU)

• FAPESP's process: 19/20108-7 - Metacommunity: space and time dynamics of Capitellidae annelides in submarine canyons
• Grantee: José Weverton Santos de Souza
• Support Opportunities: Scholarships in Brazil - Doctorate