Banca de DEFESA: ANNE KAROLLINE RIBEIRO COSTA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ANNE KAROLLINE RIBEIRO COSTA
DATE: 27/03/2024
TIME: 15:00
LOCAL: Remoto (online via GoogleMeet)
TITLE:

Connectivity and ecology of the reef tidal spray crab  Plagusia depressa (Fabricius, 1775) in the Tropical Atlantic.

KEY WORDS:

Linear morphometry; Geometric Morphometry; Brachyura; Phenotypic plasticity; stable isotopes

PAGES: 200
BIG AREA: Ciências Exatas e da Terra
AREA: Oceanografia
SUMMARY:

The present study investigated patterns of population morphometric variations of the reef tidal spray crab, Plagusia depressa and its role in the trophic structure of coastal marine environments and oceanic islands in the Western Tropical Atlantic through approaches using morphometric analysis tools, stable isotopes of δ13C and δ15N and stomach contents. We tested hypotheses regarding  phenotypic plasticity, changes in dietary composition and trophic enrichment in response to environmental, geographic and biogeochemical factors. Individuals were collected between 2019 and 2022 conducted for the two distinct investigations as follows: first, individuals were sampled in three coastal environments and a Brazilian island region: Baia de Suape- Pernambuco (SB), Praia de Tamandaré- Pernambuco (TM ), Barra Grande- Ceará (BG) and Archipelago of Fernando de Noronha- Pernambuco (FN); for the second, the specimens were sampled in a coastal marine environment (TM) and an island environment (FN). Linear and geometric morphometric analyzes were used using specific landmarks on the carapaces, abdomens and right chelipods of male and female aratus. Important significant differences were observed in the westernmost region (BG) of the Brazilian coast in relation to the others studied, such as elongation of the carapace regions of males and abdominal narrowing, longer telson and thinned and elongated chelae of females in this area, indicating the possible influence of a biogeographic barrier present in this coastal area, previously little considered, along with the patterns in ocean currents acting in this environment. In contrast, it was observed that island females (FN) had a wider posterior lateral region of the carapace. As it is further away from the continent, FN has distinct environmental characteristics, affecting the population through desiccation and greater sun exposure. The right chelae of males showed significant differences between the areas studied, indicating a significant impact of food capture and interaction with other organisms on their phenotypic plasticity. The results of feeding ecology indicated that the species has a preference for marine macroalgae according to the stomach contents analyzed, with a total of 25 taxa of marine algae found in individuals in FN and 21 taxa in TM. Higher values in δ13C fractionation were observed in TM than in the more oceanic environment (FN) in the studied groups of algae, tissues and stomach contents of P. depressa and Eriphia gonagra, a sympatric species, indicating the influence of mangrove and estuarine systems strongly present in this coastal area. However, a pattern of δ15N enrichment in the island environment (FN) in the studied groups with enrichment values of 2.8‰, 2.1‰ and 1‰ of δ15N for macroalgae and tissues of P. depressa and E. gonagra, respectively , showing that in biogeochemical systems, the large-scale nitrogen cycle is distinct in oceanic and coastal environments. Enrichment was also observed between consumers (P. depressa and E. gonagra) and food sources (macroalgae), with δ15N enrichment in P. depressa of 3‰ and 3.8‰ in FN and TM, respectively, and 2.5‰ and 4.5‰ for E. gonagra. These results provide new ecological information and perspectives for populations of Plagusia depressa, with important implications for the biogeography of the Tropical Atlantic and the development of management plans for  marine ecosystems.

COMMITTEE MEMBERS:
Externa à Instituição - ANA CARLA ASFORA EL DEIR
Interno - 3360049 - PATRICIO ALEJANDRO HERNAEZ BOVE
Interno - 2330768 - PEDRO AUGUSTO MENDES DE CASTRO MELO
Presidente - 2309616 - RALF SCHWAMBORN
Externa à Instituição - RENATA AKEMI SHIMOZAKI MENDES - UFRPE