Blue Economies - The Seas Affect Our Lives in Many Ways

Blue economies are another recent catchword, which indicates economical activity associated mainly with marine environments. From the environmental point of view there are a couple of things that need to be realized.

First, marine pollution is a huge problem. It is probably the biggest single factor behind climate change. Because of the large sea area, algae, largely unicellular microalgae, contribute 40-50 % of the total photosynthesis of the earth. Although in certain areas microalgal growth has increased, it has been estimated that owing to marine pollution the overall amount of carbon dioxide fixed by algae has decreased 10-20 %. This decrease of carbon dioxide sink is greater than that caused by recent rainforest cuts. An important component of marine pollution which has recently got much attention is plastic pollution. A lot has been talked about microplastics, but the weathering of plastics generates even smaller components, nanoplastics, which affect phyto and zooplankton. Their effects can be direct, but additionally they can result in hydrophobic environmental pollutants to become concentrated and available to organisms.

Second, world's seas are overfished. Environmentally, the use of cultured fish would be better than supporting fishing that can cause extinction of the most popular food species within 100 years. However, the problems with aquaculture are the present marked use of antibiotics and pesticides. Both should be diminished. Also, at present the feed is mainly fish flour, which means that overexploitation of natural fish is not reduced by aquaculturing, only changed to species with less human consumption. So, environmentally friendly aquaculture would require development of feeds that are not based on fish flour.

These are two things that need to be considered when developing blue economies.