Banca de QUALIFICAÇÃO: JESSICA BLEUEL

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : JESSICA BLEUEL
DATE: 06/09/2023
TIME: 14:00
LOCAL: SALA 1- DOL com transmissão via Google Meet
TITLE:

TAXONOMIC, FUNCTIONAL, AND TROPHIC DIVERSITY OF CORALS AND RESPONSES TO THERMAL STRESS

KEY WORDS:

diversity; functional traits; trait space; trophic ecology; growth; thermal stress; bleaching;

PAGES: 72
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Corals play unique roles and are critically important in reefs, but they are threatened by rising ocean temperatures causing bleaching events that can lead to loss of coverage, diversity, and reef complexity. Considering that approaches based on functional traits can provide insights into their responses to environmental disturbances, understanding patterns of coral diversity and their traits, as well as their responses to climate change, is fundamental. In Chapter 1, we describe the taxonomic and functional diversity of corals in Brazil, evaluating species composition and the functional space occupied among regions. We observe clustering of eight regions, where Bahia holds the highest species richness and proportion of occupied functional space, both decreasing with distance from this region. Species composition and regional distribution are influenced by environmental barriers and filters and related to coral traits. In Chapter 2, we investigate the fatty acid profile, trophic plasticity, and trophic mode of corals along 21° of latitude on the Brazilian coast. We note that at higher latitudes (16°S to 24°S), the total concentration of fatty acids and the fatty acid marker concentration for heterotrophy (CGA) increase. Coral species showing differences in fatty acid composition among regions exhibit trophic plasticity, while those without differences do not. Moreover, based on CGA concentrations, Porites astreoides is the least heterotrophic coral, whereas Mussismilia hispida is the most heterotrophic. Coral growth form is also an important attribute due to the addition of calcium carbonate to the reef environment. Thus, in Chapter 3, we experimentally assess the relative contribution of autotrophy and heterotrophy-based feeding modes on the growth of Millepora alcicornis and Montastraea cavernosa corals, and how they respond to thermal stress. We observe a higher growth rate for M. alcicornis compared to M. cavernosa. The dissolved organic matter (DOM) feeding treatment initially positively influenced coral growth for M. cavernosa, which was not sustained over time, and had a later positive effect on M. alcicornis. Thermal stress had limited impact on growth and the dominant trophic mode of both species. However, it negatively impacted the photochemical efficiency (Fv/Fm) and coloration of M. alcicornis (temperature-sensitive), yet corals under the DOM feeding treatment were less susceptible and showed greater recovery after thermal stress. On the other hand, the health of M. cavernosa (temperature-resistant) was unaffected by thermal stress. Thus, through the integration of these chapters, we aim to better understand the potential geographic expansion of corals based on their traits, and the role of heterotrophy in coral growth, resistance, and resilience to thermal stress.

COMMITTEE MEMBERS:
Presidente - 2319234 - GUILHERME ORTIGARA LONGO
Interna - 2412921 - JULIANA DEO DIAS
Externa à Instituição - AMANA GUEDES GARRIDO