Study of interaction between marine microorganisms and organic matter essential to understanding state of marine environment

Piran, 26 February - Microorganisms play a key role in the process of circulation of elements such as carbon, nitrogen, phosphorous and sulphur in the marine environment. Despite being the smallest among marine organisms, they are the most numerous, productive and diverse members of the food chain. To understand the role of microorganisms in the marine environment, we need to understand their number, role and colonisation, says Dr Tinkara Tinta, a researcher at the Piran Marine Biology Station. The results of Tinta's PhD research represent an important contribution to understanding the ecology of coastal waters.

The central topic of Tinta's research has been the effect of varied concentrations of inorganic and organic matter on the structure and activity of bacterial colonies in the marine environment and their impact on biogeochemical cycles in seas and oceans. "We are only now starting to understand these interactions and need to study them in detail to be able to predict the response of marine ecosystems to natural and anthropogenic factors."

The study conducted by Dr Tinta employs long-term monitoring of the size, productivity and type of microorganism colony in relation to the changing conditions of the environment using models and association networks to determine the possibility of predicting a response of the marine environment to climate change and anthropogenic influences.

The experiments conducted by Dr Tinta represent an important contribution to understanding the role of microorganisms in circulation of substances in the environment and phenomena such as algal blooms and mass jellyfish invasions. They also help improve understanding of how the introduction of pathogenic microorganisms alters the marine environment for humans and for existing wildlife.

Research on jellyfish

Research on the influence of organic nutrients on the activity of bacterial colonies focused on the effect of jellyfish substrate (organic nutrients from jellyfish) on the structure and function of bacterial colonies in the marine environment. A number of experiments were conducted using various species of jellyfish to monitor the effects of decaying matter from the jellyfish on bacterial colonies and coastal ecosystems.

Mass invasions of jellyfish have occurred frequently in coastal seas in the past decade. Jellyfish have few natural enemies. Their natural death and decay helps form a rich organic substrate that promotes the growth of bacterial colonies. This can in turn have a significant impact on the environment, says Dr Tinta.

Research has shown that the bacterial decay of jellyfish biomass leads to increased levels of dissolved proteins and organic and inorganic nutrients in the sea. "We monitored the interactions between bacteria and jellyfish substrate, including with the help of stable isotopes, and demonstrated that bacteria spurred from organic jellyfish matter prefer uptake of nitrogen substances, causing carbon rich matter to accumulate in the marine environment. The process therefore significantly impacts the carbon-nitrogen cycle," she says.

The doctoral thesis by Dr Tinta also examines the role of microorganisms in the formation of marine mucilage in the Gulf of Trieste. Coastal waters of the northern Adriatic are impacted by river run-off which introduces nutrients, especially nitrogen phosphorous, that spur algal blooms. As a result, the quantity of nutrients in the gulf, which is usually low, increases significantly. Bacteria are unable to break up such a large quantity of organic matter. The result is a seasonal abundance of dissolved organic carbon, which can in turn cause marine mucilage, says Dr Tinta,

About Dr Tinkara Tinta

As a young visiting researcher, Dr Tinta worked in the laboratory of Professor Dr F. Azama at the University of San Diego, where she went on to enrol in her post-doctoral course for which she received a Fulbright Scholarship. During her study she began researching the interactions between marine microorganisms and organic matter at individual cell level using techniques such as laser confocal microscopy and atomic force microscopy.

She also worked as a visiting doctoral student in the laboratory of the late Professor Dr Jure Piškur at the University of Lund in Sweden. The project studying deoxynucleoside kinase enzymes in maritime bacteria earned her a research scholarships from the FEMS association.

After obtaining her degree in biochemistry from the Faculty of Chemistry at the University of Ljubljana she became a young researcher under the guide of mentor Professor Dr Valentina Turk in the laboratory for maritime microbiology at the Piran Marine Biology Station. There she helped introduce molecular techniques for analysis of species composition of bacterial colonies.

Piran Marine Biology Station

The Piran Marine Biology Station was established in 1969 as a part of the National Institute for Biology in Ljubljana. Initially the station was focused on researching local flora and fauna, but eventually grew into a larger research institution conducting environmental, pollution and interdisciplinary research of the marine environment.

The station is the only research institution in Slovenia conducting scientific work related to the sea. It employs 35 people, including 19 researchers, eight early stage researchers and eight technical and administrative assistants. Students and residents of pre-graduate and post-graduate studies are occasionally involved in the research.

Cooperation chart for Tinkara Tinta

Source: Atlas of Science