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| Author(s): |
Nayara Ferreira Carvalho
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto Oceanográfico (IO/DIDC) |
| Defense date: | 2024-08-26 |
| Examining board members: |
Paulo Yukio Gomes Sumida;
Marcelo Visentini Kitahara;
José Angel Alvarez Perez
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| Advisor: | Paulo Yukio Gomes Sumida; Erik E Cordes |
| Abstract | |
This thesis investigated deep coral habitats in southeastern Brazil, first examining their composition, distribution, and morphological characteristics and correlating aspects of their establishment and development with historical data on temperature and salinity, as well as their structuring within different water masses. Building on this, the biotic and abiotic variables explored in the first chapter provided a foundation for studying the sessile and mobile coral-associated megafauna to identify assemblage structure and habitat-substrate affiliations. Recognizing the dynamic nature of these environments, four additional coral habitats at two different depths were selected (in the adjacent basin due to logistical considerations) to investigate how fluctuations in environmental variables influenced changes in the associated mobile megafauna over time, and to assess the structuring of the community. Due to a collaboration with Petrobras, data collection employed advanced tools such as a multibeam echosounder, environmental characterization videos obtained with ROVs, a series of CTD casts over the continental shelf and slope, and an underwater observatory equipped with cameras, strobe, ADCP, CTD, and chlorophyll and turbidity sensors. Among the key findings, we highlight the publication of a photographic list of 63 deep-sea coral taxa in the Santos Basin; the three deep-sea coral morphological characteristics found in the Santos Basin, with Desmophyllum pertusum reefs developing on the upper slope under the influence of the South Atlantic Central Water, with a known temperature variation of 12.4 to 16.6 °C, and coral carbonate mounds predominating on the intermediate slope under the influence of the Antarctic Intermediate Water, with a dominance of Solenosmilia variabilis; the significant role that dead framework and D. pertusum played in predicting the occurrence of sessile and mobile organisms associated with these coral habitats; and the main predictors of variations in mobile megafauna within these coral habitats over time, such as fluctuations in current components (vertical and horizontal), chlorophyll, and turbidity. All findings, detailed across three primary research chapters, unveiled these environments\' intricate complexity and heterogeneity in deep Brazilian waters. (AU) | |
| FAPESP's process: | 18/13141-5 - Spatial distribution and temporal dynamics deep-sea corals from Santos Basin, and their role as biodiversity hotspots |
| Grantee: | Nayara Ferreira Carvalho |
| Support Opportunities: | Scholarships in Brazil - Doctorate |