Microorganisms are microscopic in size and are the smallest forms of life existing in most habitats worldwide. Rocky coastlines support a rich biodiversity of specialised microorganisms that are adapted to unique microenvironments. A master of science by research was conducted into this interesting subject, to describe the microorganisms growing along the shoreline in Sliema. The research was carried out by Sarah Schembri and was supervised by Gabrielle Zammit, from the Biology Department of the University of Malta.

In various microenvironments along the rocky shore, the microorganisms are exposed to a variety of stressors including desiccation, temperature, nutrient limitation, high ultraviolet (UV) radiation and salinity variations. To successfully survive such adverse conditions, these microorganisms form biofilm communities on the rock surface, that are typically one to several cell layers thick, or multilayered microbial mat communities that range from a few millimetres to a centimetre in thickness.

Biofilm and microbial mat communities inhabit the coastal ecosystem around the Sliema shoreline throughout the year

Biofilm and microbial mat communities inhabit the coastal ecosystem around the Sliema shoreline throughout the year. However, these communities are understudied, both in Malta and in the central Mediterranean. When observed under the microscope, the biofilms and microbial mats were found to be highly diverse and self-sustaining communities, made up of different types of microorganisms. The results of this research were published in a scientific paper in the Journal of Coastal Research, titled The biodiversity of epilithic microalgal communities colonising a central Mediterranean coastline.

In coastal environments, biofilm and microbial mat communities are highly dependent on the presence of light. In fact, the main microorganisms in these microbial communities were photosynthetic microorganisms known as cyanobacteria and microalgae. Photosynthetic microorganisms play a major role in microbial communities since they use sunlight to synthesise organic matter and generate oxygen through photosynthesis. These are then utilised by non-photosynthetic microorganisms present in the community. A number of different strains of cyanobacteria from these microbial communities were recorded for the first time from the Sliema coastline during the study. This provides new knowledge and understanding of these diverse and understudied microbes, which are not harmful to human health.

This research work was conducted at the Lab of Applied Phycology of the Centre for Molecular Medicine and Biobanking of the University of Malta and was funded by the ENDEAVOUR Scholarship Scheme (Malta), which is part-financed by the European Union - European Social Fund (ESF) under Operational Programme II - Cohesion Policy 2014-2020, “Investing in human capital to create more opportunities and promote the well-being of society”.

Sound Bites

•        Cyanobacteria are found all over the world, even in extreme environments. Yellowstone National Park, located in the United States, is an extraordinary collection of hydrothermal features including hot springs. Heat-loving microorganisms called thermophiles live in these features forming colourful and vibrant microbial mats. Cyanobacteria are found in some of these mats where they can survive in waters as hot as 73 degrees Celsius.

•        Certain environmental conditions in freshwater and marine environments enable some species of cyanobacteria to grow very quickly, causing blooms with a visible discolouration of the water. Some cyanobacteria that produce these blooms are capable of producing substances that are highly toxic, known as cyanotoxins. Harmful blooms threaten aquatic ecosystems and degrade water quality, which may possibly be dangerous to human health by affecting drinking water and activities such as swimming and fishing.

•        Results of the research carried out to describe the microorganisms growing along the shoreline in Sliema are published in the scientific paper that can be accessed here.

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DID YOU KNOW?

•        Cyanobacteria represent the earliest known form of life on earth. They are thought to be the very first organisms to evolve and develop photosynthesis.

•        Cyanobacteria are used as food by several aquatic organisms.

•        The dietary supplement spirulina, associated with many health benefits, is a cyanobacterium that is now called Arthrospira.

•        The Red Sea gets its name from occasional blooms of a cyanobacteria called Trichodesmium erythraeum which accumulate and give the sea a red hue.

For more trivia, see: www.um.edu.mt/think.