Algae and Chain Aquaculture: An Approach Towards Sustainable Agriculture

Global warming, water scarcity and the rise of sea level have resulted in drastic changes that lead to shortage of living resources needed to meet the demands of the ever-increasing human population. Moreover, the contaminated and the poor quality of resources available represent challenges for any sustainable development plans. The major challenges that hinder the establishment of sustainable agriculture are the limited water resources, the limited fertilizer supply and the limited hospitable space (where edible food and water exist) for placing the population. Also, eco-friendly solutions that are not hazardous or polluting are needed to suffice the living and space demands of the increasing population. In Egypt, the population is mainly centred in the delta area and the narrow fertile Nile valley. This is uneven demographic distribution as most of Egypt’s area is uninhabited deserts. Desert lands that represent more than 95% of the total area of Egypt can provide a solution for the lack of hospitable space and establishing new sustainable communities. The present chapter discusses a proposed working model in which algae play major roles. Algae, the photosynthetic plantlike organisms, are important part of the different global ecosystems. Nevertheless, they have been underexploited in case of agriculture despite their indispensable role as primary producers and as a rich source of nutrients and bioactive compounds as well. Our model is based on using innovative strategy of integrating the culturing of algae, fish and plants in a sustainable aquatic chain. The unpolluted underground water, which is mostly brackish, provides a solution to the limited water resources and is to be used for establishing algal and fish cultures. Algae are to be used as fish feed in part and as biofertilizers for plants. The algae are to be mass cultured using an economic open culturing pond/system. Meanwhile, the fish wastewater would be reused for the irrigation of plants where the phosphorus, nitrogen and organic matter in the wastewater represent natural fertilizers for plants. The plants are also to be biofertilized using algal bioconcentrate/biomass. This integrated system in which algae play multiple roles would hopefully offer solutions to obstacles hindering sustainable agriculture.