Increased knowledge of breathing to understand acid-free seabed

The results of Kevin Vikströms' thesis in a coastal region of the Baltic Sea show that a decrease in nutrients, and therefore growth, does not necessarily reduce oxygen consumption. Kevin Vikström proposes a new perspective on the management of the marine environment where maintenance needs to be considered. He defends his thesis on November 9 at the University of Umeå.

An increase in oxygen-free areas as well as a decrease in oxygen in coastal areas have been observed worldwide in recent years. This leads to areas where no fish, shellfish or crustacean can live. In order to fight against the appearance of an oxygen deficiency, it is necessary to better know the distribution of the oxygen consumption caused by the growth and the maintenance of the breathing.

Breathing means that carbon compounds and oxygen are converted into energy. All animals living in the ocean need energy for their growth, but also for their functions, which means that energy is used to move, maintain vital functions and repair damage.

Already in the 1970s, one could measure a need for oxygen even without growth of bacteria, and a model was developed to describe the so-called bacterial maintenance spirit. The model was developed further in the 1980s, but until now, everything was based on laboratory cultures. Another concept similar to the spirit of maintenance has also been developed at the level of the ecosystem, where the growth of photosynthetic microscopic plants has been used as an explanatory variable. The concept calls basic breathing and is defined as acid consumption when photosynthesis is negligible. Coal from rivers and groundwater, for example, can be used for respiration and thus disconnects the primary production of the respiratory system. The effect of respiration and basic maintenance on ecosystems has not been studied.

Kevin Vikström has studied these concepts in a coastal area of ​​the Baltic Sea and presents an initial estimate of the annual contribution of basic maintenance and bacterial maintenance. His results show that the model describing bacterial maintenance respiration works to some extent under conditions of high productivity and would lead to a 58% contribution of maintenance breath to annual bacterial respiration. . Basic breathing was also important and accounted for 50% of the annual oxygen consumption in the body of water.

– In a broader perspective, the results show that a decrease in bacterial growth using reduced amounts of nutrients does not necessarily reduce the oxygen consumption of bacteria. Instead, growth-based breathing switches to maintenance breathing with a marginal difference in total oxygen consumption as a result, explains Kevin Vikström.

Base alcohols were mainly derived from coal supplied to the coast by rivers. As a result, there may be different levels of basic breathing in different environments. In an ecosystem where basic breathing is high, a reduction in nutrients will not necessarily reduce oxygen consumption. On the other hand, it is located in an environment where the production of algae by the sea is the main source of coal.

Breathe to maintain vital functions, but not growth, in the ecosystem can be high in coastal areas. Thus, the current growth-oriented environmental management strategy may be inadequate.

"Basic management and maintenance is crucial to take into account the understanding and management of the development of low-oxygen coastal areas in an efficient and economical way," says Kevin Vikström.

Read the full thesis

About the thesis:
On Friday, 9 November, Kevin Vikström, Department of Ecology, Environment and Geosciences of the University of Umeå, defends his thesis entitled: Importance of maintaining bacteria respiration and basic breathing for the development of coastal hypoxia.

The thesis will take place at 9:00 Sal N440 at the Natural Sciences Center of Umeå University.

The opposing professor is Josep M. Gasol, Department of Biology, Marina in Oceanography, Institute of Cultural Affairs, Maric – CSIC

For more information, please contact:

Kevin Vikström, Department of Ecology and Geoscience
Phone: 073-049 00 07
E-mail: [email protected]

Press picture. Photo: Mattias Pettersson