TROPICAL COASTAL ECOSYSTEMS

03 March 2021, 6 pm CET

Tropical coastal ecosystems (TCE) are among the most diverse and complex ecosystems in the World. Coral reefs, seagrass meadows and mangrove forests represent a habitat for more than 25% of the marine species. It’s hard to overestimate the value of the TCE for local communities. Coastal ecosystems provide various ecosystem services for fisheries, shoreline protection and tourism. At the same time, they represent one of the most rapidly declining ecosystem complexes. To date, more than 50% of coral reefs, 35% of mangrove forests and 29% of seagrass meadows were lost. The research, rational and sustainable exploitation and conservation of these ecosystems is the matter of concern of scientists and stakeholders around the globe.

At the present forum we will address several questions. How diverse are TCE? How the species inhabiting these ecosystems relate to each other and the habitats? Which physiological adaptations have the species inhabiting TCE? What are the impacts of anthropogenic pressure on TCE? Are there truly sustainable ways to use these ecosystems?

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Speakers and Abstracts

Establishment of coral associated symbiotic communities in aquaculture

Prof Dr Temir A. Britayev1*

1Head of the Laboratory of Ecology and Morphology of Marine Invertebrates A.N. Severtzov Institute of Ecology & Evolution RAS Moscow, Russia

*corresponding author: ur.xe1734801143dnay@1734801143veyat1734801143irb1734801143

Keywords: coral reefs, structure of symbiotic community, resilience, research methods, aquaculture

Coral reefs are one of the most productive and species-rich ecosystems in the World Ocean.  They are based on colonies of scleractinian corals, which form a three-dimensional carbonate framework that provides refuge for mobile and immobile organisms. According to various estimates, coral reefs are inhabited by 172,000 to 9 million species. The vast majority of these species are small invertebrates and fish that live on the surface or within various living substrates such as sponges, echinoderms and corals. Without exception, all scleractinian corals are inhabited by specialized multicellular organisms: ecto – and endosymbionts, which depend on corals. Symbionts use coral for shelter, as a food source, as a place where they reproduce and incubate juveniles. At the same time, the resilience and fitness of host corals depend on the presence of the symbiotic community (SC) and is often determined by this factor. Thus, SC associated with corals is one of the most important components in the life of the reef. Symbionts have a positive effect on coral, increasing their resilience to intense sedimentation, provides nutrients to the host, which accelerates coral growth, aerate the interior of corals, protect them against infections and parasites. Nevertheless, the process of the establishment of symbiotic communities, its main stages and factors determining its trajectories and rate have not been studied yet. The lack of these data is associated with methodological difficulties. There are currently two main approaches used to study coral-associated symbiotic communities: (1) removal of colonies from nature and extraction of symbionts from them, and (2) visual registration of symbionts under water using diving technique. Both approaches have advantages and disadvantages. (1) Removing colonies, we are obtaining exact quantitative data on the composition of the SC, abundance and size of symbionts. Removing colonies, however, damages them. (2). Visual registration of symbionts does not require removal and destruction of colonies. However, it cannot provide information on all categories of symbionts. The aim of this report is to tell about the approach developed by us, combining the advantages of two mentioned above, and to study the process of establishment of symbiotic communities. Planting corals from fragments on artificial constrictions in natural environment is applicable to most life forms of corals and, allows you to get a large number of colonies at different stages of formation. Using this approach, we got answers to the following questions: (1) at what stage of the establishment of a coral colony do the first symbionts appear? (2) What species symbionts, obligate or facultative, prevail among the first colonists in the young colonies? (3) Are there pioneer species (fast colonists – opportunists) and slow colonists (specialists) among colonists? (4) Does the proximity of large adult colonies affect the process of young colonies occupation?

At the discussion we aim to address such questions as:

1) What are the major anthropogenic threats for Tropical Coastal Ecosystems (TCE) around the globe?

2) What are the most efficient methods of conservation and/or exploitation of TCE?

3) What are the most promising approaches to recovering of the coral reefs and the mangrove forests?

4) Which fields of research of TCE appear to be the most promising?

Videos

Establishment of coral associated symbiotic communities in aquaculture

Prof Dr Temir A. Britayev 1

Coral reefs are one of the most productive and species-rich ecosystems in the World Ocean. They are based on colonies of scleractinian corals, which form a three-dimensional carbonate framework that provides refuge for mobile and immobile organisms. According to various estimates, coral reefs are inhabited by 172,000 to 9 million species. The vast majority of these species are small invertebrates and fish that live on the surface or within various living substrates such as sponges, echinoderms and corals. Without exception, all scleractinian corals are inhabited by specialized multicellular organisms: ecto – and endosymbionts, which depend on corals. Symbionts use coral for shelter, as a food source, as a place where they reproduce and incubate juveniles. At the same time, the resilience and fitness of host corals depend on the presence of the symbiotic community (SC) and is often determined by this factor. Thus, SC associated with corals is one of the most important components in the life of the reef. Symbionts have a positive effect on coral, increasing their resilience to intense sedimentation, provides nutrients to the host, which accelerates coral growth, aerate the interior of corals, protect them against infections and parasites. Nevertheless, the process of the establishment of symbiotic communities, its main stages and factors determining its trajectories and rate have not been studied yet. The lack of these data is associated with methodological difficulties. There are currently two main approaches used to study coral-associated symbiotic communities: (1) removal of colonies from nature and extraction of symbionts from them, and (2) visual registration of symbionts under water using diving technique. Both approaches have advantages and disadvantages. (1) Removing colonies, we are obtaining exact quantitative data on the composition of the SC, abundance and size of symbionts. Removing colonies, however, damages them. (2). Visual registration of symbionts does not require removal and destruction of colonies. However, it cannot provide information on all categories of symbionts. The aim of this report is to tell about the approach developed by us, combining the advantages of two mentioned above, and to study the process of establishment of symbiotic communities. Planting corals from fragments on artificial constrictions in natural environment is applicable to most life forms of corals and, allows you to get a large number of colonies at different stages of formation. Using this approach, we got answers to the following questions: (1) at what stage of the establishment of a coral colony do the first symbionts appear? (2) What species symbionts, obligate or facultative, prevail among the first colonists in the young colonies? (3) Are there pioneer species (fast colonists – opportunists) and slow colonists (specialists) among colonists? (4) Does the proximity of large adult colonies affect the process of young colonies occupation?

 

1Head of the Laboratory of Ecology and Morphology of Marine Invertebrates A.N. Severtzov Institute of Ecology & Evolution RAS Moscow, Russia