Biodiversity of invertebrates associated with the newly revealed rhodolith bed of Couves Island, Ubatuba, São Paulo.

• Grant number: 24/15408-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2025
• End date: January 31, 2026
• Field of knowledge: Biological Sciences - Ecology
• Principal Investigator: Guilherme Henrique Pereira Filho
• Grantee: Giovanna Augusto Costa
• Host Institution: Instituto do Mar (IMar). Universidade Federal de São Paulo (UNIFESP). Campus Baixada Santista. Santos , SP, Brazil

Abstract

Rhodolith beds are structures composed of the accumulation of calcified algal nodules that typically occur on sedimentary seafloors. These beds provide a variety of ecological resources, acting as microhabitats for invertebrates, algae, and fish, thereby increasing local heterogeneity and the diversity of associated fauna when compared to other types of seabeds. In 2023, LABECMar revealed the existence of a rhodolith bed on the northern coast of São Paulo, located at Couves Island, Ubatuba, ranging from 5 to 12 meters in depth, and presenting nodules with larger diameters compared to other beds along the Brazilian coast. The newly revealed bed may harbor a high diversity of associated organisms due to the presence of different taxa at the site, but its associated biodiversity and characteristics have yet to be described by any systematic study, thus remaining a largely unknown environment. In general, there is still a lack of data in the literature regarding the occurrence and ecological roles of this rhodolith bed on the Brazilian coast. Therefore, the generation of knowledge about the biodiversity associated with these beds is urgent, given that they are habitats susceptible to the increasing impacts on the coastal zone experienced in recent decades. In this context, the present project proposes the first survey of the biodiversity of invertebrates associated with the newly revealed rhodolith bed at Couves Island. The study will assess the organisms of its vagile macrofauna, including its epifauna and infauna, through the sorting of samples collected manually on-site via scuba diving and fixed in absolute ethanol. The structural aspects of the bed will also be considered, highlighting characteristics such as the complexity and size of the collected nodules. All vagile macroinvertebrate fauna will be identified to the highest possible taxonomic resolution, with the best-preserved specimens photographed for the preparation of photographic plates. Differences in species composition between epifaunal and infaunal organisms will be tested using a Permutational Multivariate Analysis of Variance.