LEARNING OUTCOMES

The module aims to provide basic knowledge on the characteristics and functioning of tropical coastal ecosystems, and on the ecological role of the main components / key species of each ecosystem. In particular, the module has the following main objectives: 1) describe the features of tropical coastal marine environments; 2) explain the functional relationships between seagrass meadows, mangroves and coral reefs; 3) describe coral formations, theories on the genesis of coral reefs, the relationship between bioconstruction and biodiversity; 4) understand the ecological, trophic, constructional and biosedimentological role of the main groups of reef organisms; 5) describe the zonation of the reef ecosystem; 6) introduce the four tropical marine regions of the planet.

AIMS AND LEARNING OUTCOMES

Classes attendance will enable the student to acquire the necessary knowledge to understand the importance of studying tropical marine ecology. In particular, the students will acquire the ability to recognize and describe the main key components / species of each tropical marine ecosystem, defining their ecological role in maintaining the functioning of the ecosystem itself. They will also acquire the knowledge to recognize, thanks also to the material conserved in the DiSTAV collections, the main coral builders of the reef, the main benthic organisms that can be observed on a reef, and the main families of reef fish. They will also be able to recognize and describe the different tropical biogeographical zones of the planet.

PREREQUISITES

The basic notions of ecology and coastal marine ecology are useful to effectively address the contents of the module. During the first classes the main characteristics of coastal marine ecosystems and their functioning will be re-called, in particular the benthos-pelagos connection.

TEACHING METHODS

The module consists of lectures in presence, for a total of 24 hours. During the lectures it will often be shown examples of organisms typical of the tropical environments, conserved in the personal collections at DiSTAV, and in particular specimens of coral reef builders, which will facilitate understanding of their characteristics and the recognition of the main families.

Lectures in the classroom are delivered through multimedia presentations. As there is no reference text adopted, class attendance is strongly recommended. The student can make use of the material made available on Aulaweb.

Please refer to the specific AulaWeb application for this teaching for any updates due to changes in the health and epidemiological situation and for any further update.

SYLLABUS/CONTENT

The program includes:

Definition of tropics and characterization of the intertropical oceanic belt. Importance of the study of tropical marine ecology. Framework of tropical coastal marine environments in the general ecological characteristics of coastal systems. Importance of benthos and benthos-pelagos connection: flows; biological cycles; endosymbiosis. Spatial zonation in three dimensions. Productivity: Darwin's paradox and possible explanations; categories of primary producers; plankton (oceanic, coastal, demersal). Heterogeneity and biodiversity. Theory of parallel communities. Rocky intertidal: nature of rocks and formation of coral islands. Sandy beaches. Biotic zonation: similarities and differences with temperate seas. Functional interrelations between seagrass meadows, mangroves and coral reefs. Meta-ecosystem concept. Coral lagoons and seagrass meadows. Importance of marine phanerogams. Specific and morphological diversity of tropical marine phanerogams. Composition, structure and zonation of seagrass. Associated biota. Trophic network of the phanerogam ecosystem. Consumers of marine phanerogams.

Mangroves. Worldwide distribution. Definition of mangrove. Ecophysiological adaptations of mangroves. Saline balance. Life cycle, germination. Aerial roots, pneumatophores. Morphological and taxonomic diversity of mangroves. Zonation. Environmental characteristics of the mangroves. Associated biota and community of mangroves. Trophic network of the mangrove ecosystem. Coral formations: coral communities and coral reefs. Types of coral reefs: 1) marginal or fringing reef; 2) barrier; 3) atoll; 4) tabular reef or platform, 5) pinnacle. Constructional morphologies, inherited morphologies, residual morphologies. Theories on the genesis of coral reefs, from Darwin to Purdy. Subsidence and eustatism, "Darwin point", glacial control, marine erosion, karst corrosion. Abrasion platforms, terraces and caves. Witnesses of erosion and corrosion.

Bioconstruction. Biological, geological and ecological aspects. Importance of bioconstruction: scientific, ecological, economic, environmental, climatic. CO2 cycle, carbon flow and calcification: coral reefs as CO2 sources. Definition and terminology. Concepts of elevation (positive topography), persistence, hydrodynamic resistance. Role of stress and disturbance. Climatic constancy. Bioconstruction and biodiversity. Mediterranean bioconstructions. Dynamic aspects of bioconstruction. Bioconstruction as a self-organized and unpredictable historical process. Relations between bioconstruction and sea level changes. Models keep up, give up, catch up.

Concepts of superstratal and constratal growth. Aggregation and progradation. Bioarms and biostromes. Coral formations. Bioconstructor organisms: definition of hermatipic, constructional, zooxanthellate. Ecological roles. Guild or guild concept referring to the genesis and maintenance of the coral reef. Primary and secondary builders; encrusting binders; deflectors; sediment producers; inhabitants; destroyers. Bioerosion. Internal and external bio-destructors. Mechanical destruction and formation of coral patches. Diversity. Associated biota diversity (notes on the diversity of zooxanthellae) and diversity of builders. Oligotypical cliffs and polytypic cliffs. Hypothesis on the origin of diversity: 1) climate stability; 2) productivity; 3) antiquity. Hypotheses on the maintenance of diversity: 1) environmental heterogeneity (habitat and microhabitat); 2) niche specialization; 3) lottery; 4) intermediate disturbance. The reef organisms. Philetic and specific diversity. Type and importance of physiological and behavioral symbioses. Ecological, trophic, constructional, and biosedimentological role of the main groups of organisms. Coral biology and ecology. Solitary forms and colonial forms. Skeletal structure; biomechanical characteristics. Basics of functional anatomy. Nutritional cycle in zooxanthellate corals. Sexual reproduction: emission and incubation. Mass emission, synchronization. Asexual reproduction, intracalicinal and extracalicinal budding. Morphologies and species recognition. Main growth forms (digitate, branching, tabular, submassive, massive, columnar, encrusting). Intraspecific variability. Taxonomic descriptors (biodiversity) and non-taxonomic (ecological indicators). Approach to the recognition of some significant families: Acroporidae, Faviidae, Poritidae, Fungiidae, Pocilloporidae, Dendrophylliidae. Corals potentially constructing in the Mediterranean. Relationship between growth forms and environmental factors, abiotic (light, hydrodynamism, sedimentation) and biotic (competition). Indirect competition or by subtraction of resources: shadowing; direct competition or interference: extracelenteric digestion. Coral predators. The COT phenomenon. Coral diseases, concept of pathogenic microbial consortium. Bleaching: causal hypotheses and consequences. Mortality (partial and total), Phoenix effect, recovery. Zonation of the reef ecosystem. Pichon's model. Recifale biocenosis (polytrophic) and subrecifale (planctotrophic) biocoenosis. Algal crest. Relative role of light and hydrodynamism. Vertical and horizontal zonation of growth forms. Morphology of bioconstruction: spurs and grooves. Interrelations corals - algae - sea urchin- herbivorous fish. Bottom-up and top-down control. The problem of phase shift in coral reefs. Influence of climate and man.

Ecology of coral reef fish. Pelagic fish and reef fish. Vertical zonation of reef fish. Temporal niches. Food niches. Feeding methods: suction feeding, ram feeding, manipulation. Herbivores, corallivores, piscivores, bentophagi, planctophagi, categories of predators. Defense mechanisms from predators. Hazard and toxicity. Behavioral symbiosis. Importance of large groups. Mimics: crypsis or camouflage; disruptive or somatolytic colors; imitation, batesian mimic (mime and model) and mullerian mimic (mullerian chain). Aposematic communication lines. Behavioral ecology of cleaning fish. Main families of typical coral fish and their ecological role.

The four tropical marine regions of the planet: 1) western Indo-Pacific; 2) western Atlantic; 3) Eastern Pacific; 4) Eastern Atlantic. Characteristics and peculiarities (extension, coral formations, biodiversity). Affinities and differences.

RECOMMENDED READING/BIBLIOGRAPHY

The adoption of a reference text is not envisaged. Available (downloadable from Aulaweb) a copy of the presentations used during the classes (in pdf), didactic material and scientific articles for further information.