The tens of thousands of tons of seaweed that gather at the seaside exasperate every summer the tourists on the coast. The authorities and the companies that manage portions of the beach have taken energetic measures in the face of the green “attack”, spending a lot of money on equipment specialized in their collection. In some countries like Greece, seaweed is widely used in industry and biofuel production, bringing substantial income. In Romania, however, the national algae production goes directly to the landfill.
Algae have a number of features that makes them a good biological indicator of water quality: present and abundant in nearly all aquatic habitats. They are very sensitive to changes in the physicochemical nature of the water and many species present ecological requirements and tolerances well defined. There don’t seem to have preference to a certain type of substrate. They have a short development cycle and quickly colonize new habitats, so that changes at the community level show rapid responses to environmental changes.
Searching into the depths of a small entering in the Black Sea it is discovered that at a distance of 2-12 m from the water surface live 1-5 green algae species, 8-10 species brown algae and 10 to 12 species of red algae. At 25 m depth, green algae are no longer present, of brown algae survive only 5 species, and of the Red survive 8-10 species. If you are studying the water surface to the 2 m, you will find: about 20 species of green algae, 10 species of brown algae and 4-5 species of red algae. This allocation can be assigned to different penetration power through the layer of water of the different light radiation. The red radiation does not pass almost 34 m, while blue and green rays penetrate up to 500 m. But the green algae have a maximum absorption of the red light, and the red ones absorb green light.
Algae are an important agent in combating pollution and are already used worldwide in wastewater treatment, especially in the removal of nitrates and phosphorus. Their use has two major advantages over traditional practices: reducing the amount of chemicals and energy costs. These plants play an important role in many industries: textiles, aquaculture, pulp and paper, distillery, tobacco, food, chemical, patrochemical, pharmaceutical or metallurgical.
Algae can also be used as feed, as a fertilizer, but also in the process of isolating carbon dioxide, uranium and plutonium. However, the properties of marine plants do not stop at the curative effects and their important role in the biosphere. In the very near future, algae could become one of the main resources in biofuel production. In this sense, large companies have already begun to invest heavily in research.
The Romanian coast abounds in seaweed that could be exploited. Among the green ones, we have significant amounts of Ulva lactuca (sea salad), a common food in other parts of the globe. Red alga, for example, Porphyra leucosticta has a high content of vitamin C and natural carotenoids. These compounds have multiple uses in the pharmaceutical, cosmetic and food industries. Greed alga with its green pigment is a useful therapeutic agent, having extensive uses in the cosmetics industry (deodorant).
Contamination of the marine environment with domestic or industrial waters, accentuated during the summer season, when tourism is intense, has unfavorable consequences on algal vegetation, being one of the causes that led to the qualitative reduction of sensitive species, their place being taken by opportunistic green algae species, that are much more resistant to pollutants. They have a strong reproductive capacity and, once torn off by waves from the substrate, they generate deposits on the shore.
Excessive development of algae during the warm season (eutrophication) is considered a normal response to environmental conditions (high temperature and large amount of nutrients in the water, along with a favorable transparency of the photosynthesis process). The mere existence of macrophytes is an indication of the regeneration of the marine environment, and the presence of perennial species (capable of developing over several years), sensitive to changes in the marine environment, reflects a balance between chemical and physical factors in the marine environment.
An example of a perennial species is the brown alga Cystoseira barbata, which was estimated to live up to 20 years, reaching a size of about 1.5 m. Algae with special ecological value is protected within the Marine Reserve 2 Mai – Vama Veche , whose custodian has been the National Institute for Marine Research and Development “Grigore Antipa” in Constanța (INCDM) for over 10 years. In fact, INCDM periodically carries out macrophyte monitoring activities, by identifying new species, quantitative assessments, having a tradition in this regard for several decades.
Looking at the past, we can say that the algal populations on the Romanian coast have undergone radical changes over time, the most important being the decline of perennial species and species development opportunists, who have created over the decades undesirable events, materialized with the diminution of zoobental communities and fish, for which macroalgae represented the necessary habitat.
Currently, we can say that macroalgae also follow the trend of the entire Black Sea basin, that of regeneration, referring here to perennial species, able to truly sustain an underwater life, compared to the seasonal ones, with an ephemeral existence.
Author: Giuglea Raul – President of ECOM