Title : Highly halotolerant green filamentous macroalgae cladophora vagabunda as a promising aquaculture target
Abstract:
Cladophora is a genus of green, branching, filamentous macroalgae that are found worldwide in various water bodies. certain species of cladophora are traditionally consumed as food in Southeast Asian countries and Pacific islands. Its inherent qualities are becoming more and more recognized as a valuable resource for applications in agriculture, healthcare, and various industries. Discussions are currently underway regarding the potential for cultivating cladophora spp., with ongoing research and development of various cultivation technologies. The Crimean Peninsula, the largest peninsula in the Black Sea, is renowned for its numerous hypersaline lakes and the largest hypersaline lagoon in the world, Bay Sivash.
This unique extreme environment is home to a variety of cladophora species, which flourish by forming dense mats covering vast areas. These mats can achieve impressive biomass levels, with wet weights reaching up to 5 kg per square meter. The production of algae is staggering, with sivash Bay alone generating up to 15 million tons of raw biomass annually. However, previously, scientists could not definitively determine how many species of cladophora exist in crimean hypersaline lakes due to their high morphological variability. We employed morphological and advanced molecular genetic techniques to identify the species of cladophora from two lakes with markedly different salinity levels. We discovered the presence of the identical species, cladophora vagabunda (Linnaeus) Hoek, 1963, in both saline lakes, one with a salinity level of 20 g/l and the other with a salinity of 80 g/l. C. vagabunda is widely distributed, occupying coastal marine waters in the Atlantic, Pacific, and Indian Oceans. It also thrives in saline continental environments, such as Tibet and the caspian Sea.
This species stands out for its high productivity and is one of the most successful in its genus, forming significant biomass in marine ecosystems. In the Black Sea, for example, its biomass can reach up to 2.8 kg/m2. C. vagabunda can adapt to a wide range of salinity levels and exhibits remarkable thermotolerance, growing normally at temperatures between approximately 10 °C and 35 °c. The biomass of C. vagabunda, akin to other cladophora species, is rich in a wide range of valuable components, making it a highly promising candidate for large-scale cultivation. The most promising strategy is cultivating C. vagabunda in waters with high salt concentrations. This method offers several significant advantages. Hypersaline aquaculture holds significant potential for development, leveraging both natural hypersaline water sources and artificially generated brines. By 2020, approximately 20,000 seawater desalination plants were operational globally, producing 146 million cubic meters of brine daily. Utilizing this brine in aquaculture, particularly for cultivating C. vagabunda, can mitigate environmental damage from brine discharge and reduce freshwater expenses. The additional revenue generated from aquaculture by-products can further offset these costs.
