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Projeto do CEBIMar

Dados do solicitante

Amana Guedes Garrido

Natureza do projeto

Projeto de docente ou pesquisador
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Projeto de Pós-Doutorado

Pesquisadores ou docentes associados

Marcelo Visentini Kitahara
Thiago Mendes
Carla Zilberberg
Débora Alvares Leite Figueiredo

Recursos

bolsa vinculada ao JPII coordenado por Marcelo Kitahara (2021/06866-6)
Fapesp

Descrição do projeto

Community structuring, phylogeography, and ecological traits from the Brazilian scleractinian
endosymbiont zooxanthellae
09-10-2022
30-08-2024
Since their debut in shallow-waters (circa 240 Mya), the vast majority of scleractinian corals have established a symbiotic relationship with photosynthetic dinoflagellates of the family Symbiodiniaceae. These endosymbionts, commonly known as zooxanthellae, assist corals in their nutrient production through photosynthetic activities. In brief, the zooxanthellae provide fixed carbon compounds to the coral host and, in return, the host coral provides a protected environment and a steady supply of carbon dioxide for the zooxanthellae photosynthesis. However, the millions of years that such a relationship has endured turned most shallow-water corals dependent on the zooxanthellae’s energy supply. Due to this relationship, corals and, therefore, shallow-water coral reefs are particularly sensitive to increasing temperatures as their symbiosis with zooxanthellae suffers a breakdown when temperatures are anomalously high. The breakage of this symbiotic relationship, termed “coral bleaching”, reduces the performance of the coral host, and have become more frequent and widespread in the past decades. These mass bleaching events are often associated with widespread coral mortality and, for those that survive, depressed colony growth and reproduction have been detected. On top of that, the increase in frequency and strength of ocean thermal anomalies in the last few years is resulting in more pervasive bleaching events. Nevertheless, there is growing evidence indicating that patterns of bleaching as well as bleaching susceptibility are far from homogeneous in terms of taxa and also locations. In Brazil, several localities are being affected by climate change but, our corals have been purported to have a higher resistance as heterotrophy appears to be more widespread in our more turbid waters. Furthermore, the zooxanthellae population/community structure within the coral is dynamic, and field experiments have indicated turnover in the endosymbiont community that improved hosts’ susceptibility to ocean warming at a particular place and time. Therefore, the aim of this project is to further understand the holobiont fitness/adaptation in time of increasing anthropogenic-related impacts. To achieve that, in situ zooxanthellae community profile from the Brazilian corals will be determined, and in situ and ex situ experiments will test the zooxanthellae community potential turnover due to ocean warming. Besides being the first effort to sequence genomic and transcriptomic data from Brazilian corals, the project will generate unprecedented data that will serve as a baseline for future investigations and help to answer several questions within small and large evolutionary scales.
coral bleaching; metabarcoding; coral reefs; Symbiodiniaceae; dinoflagellates
Species/populations targeted for the zooxanthellae community profiling will be sampled at 12 localities along the Brazilian coast, including 3 oceanic islands. In addition, in situ experiments will be performed at the Alcatrazes Archipelago (SP) and Natal (RN), key sites holding particularly interesting environmental conditions. The first experiment is part of an ongoing research monitoring M. hispida at the Alcatrazes Archipelago. This archipelago is under the influence of a wind-driven upwelling, which changing the water temperature by up 10 ºC within a day. Such a particular condition provides a completely different thermal environment for colonies according to their depth distribution, with colonies from the shallower depths (4 m deep) experiencing higher temperatures (especially during climate anomalies), mid-water colonies (4-8 m depth) experiencing strong temperature fluctuations, and deeper-water individuals being protected from rising temperatures by the cold South Atlantic Central Water Mass (SACW). On this locality, several colonies distributed within a ~500 m2 area from 2 to 12 m depth were tagged in May 2021 and are being continuously monitored. Tissue samples, along with images under natural (using a coral watch card) and ultraviolet lights (taken at night), will be taken at the beginning of the experiment and at every six months. Further samplings will be performed in specific cases such as bleaching alarms from NOAA, bleaching events, and bleaching recovering.
The second in situ experiment will be performed in Natal, where the target species S. stellata can be found in two highly divergent thermal environments such as tide pools, where seawater temperature can reach over 36 ºC, and infra-littoral areas with “normal” temperatures. To investigate if and how the zooxanthellae community from S. stellata from one environment shifts to acclimatize the holobiont to divergent conditions, four colonies from tide pools and four colonies from the infra-littoral sites will be divided into two fragments, one of which will be transplanted between the two environments. Transplants will be performed reciprocally between sites. Colonies will be fragmented and left to heal for two weeks when the first tissue sampling will be taken (T0). One day after the reciprocal transplants were performed, another tissue sample will be taken (T1). Additional two sub-samples will be collected on the 10th (T2) and 30th (T3) day. After T3, fragments will be relocated to their respective original sites and sub-sampled at the same time range as described above (T4-T6).
For the third experiment (ex situ), three specimens from M. hispida and M. decactis will be collected on the same day from six sites to be chosen along the Brazilian coast and maintained in a common garden (10,000 L tank). Sites will be selected to encompass areas with divergent environmental conditions. All colonies will be transported to the Center for Marine Biology and kept in an open-water system for acclimation and with freshly collected plankton offered as food every day. After acclimation (~30-40 days), the open water system will be closed and the thermal experiment will start (temperature still to be decided). Samples are planned to be taken from each colony before, during (10th day), and after the experiment has finished (~20 days). Changes in sampling time might happen as a consequence of colonies’ health.
For all the collected samples, total genomic DNA will be extracted and the identification of endosymbionts composition will be performed throughout metabarcoding (using the internal transcribed spacer 2 of the ribosomal DNA; ITS2 rDNA; ~243-266bp).
Latitudinal related sampling – previously performed
Transplant experiment 1 – second semester of 2022 and first quarter of 2023
Transplant experiment 2 – second semester of 2022 and first quarter of 2023
Ex situ experiment – second semester of 2022
DNA extraction – second semester of 2022 and first semester of 2023
DNA library preparation and sequencing – second semester of 2022 and first semester of 2023
Zooxanthellae community profiling – 2023 and first semester of 2024
Reports – August 2024
Manuscript submission – second semester of 2023 and first semester of 2024

Solicitações

Laboratório Molecular
Equipamentos para análises moleculares presentes no Laboratório Molecular, como termociclador, espectrofotômetro de
microvolumes, fluxo laminar, transiluminador, fonte e cuba de eletroforese, centrífuga, micropipetas, espaço na geladeira e nos freezers -20ºC e -80ºC.
Corais escleractinios
Arquipélago de Alcatrazes
Não se aplica
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