The underexplored potential of green macroalgae in aquaculture

Abstract

Green macroalgae (Chlorophyta) currently represent a residual fraction (<1%) of global seaweed biomass production landings. In turn, red (Rhodophyta) and brown (Ochrophyta) macroalgae dominate the remaining percentage of aquaculture production, exceeding 32 million tonnes per annum. However, the industry relies on a relatively low number of species, in which as few as seven macroalgal genera collectively represent the bulk of global production metrics. At present, innovation and increased sustainability of the industry calls for diversification of macroalgal species/strains in aquaculture to counteract potential adverse effects ensuing from genetic impoverishment, decreased resilience to disease and climate change. Despite the dominance of red and brown seaweed regarding production figures, aquaculture of green macroalgae has witnessed an increasing trend in productivity and diversification over the last decades, particularly in Asia, where green seaweed taxa often occupy specific market niches in the food sector. Furthermore, growing interest in green seaweeds in aquaculture has been highlighted for different applications in emerging western markets (eg IMTA, biorefineries, food delicacies), owing to a unique diversity of cytomorphologies, ecophysiological traits, propagation capacities and bioactive compounds featured by this group of macroalgae. Cultivation technologies are relatively well developed, but sustainability assessments are scarce and required to unlock the potential of green seaweeds. Although it is likely that green macroalgae will remain occupying specialised market niches, in which high‐value products are favoured, we argue that aquaculture of chlorophytan taxa presents itself as a compelling option under the current quest for commercial diversification of products and expansion of the sector.

Marine Autotroph-Herbivore Synergies: Unravelling the Roles of Macroalgae in Marine Ecosystem Dynamics

“…Green algae comprise of 9000 to 12,000 species, with the majority of them occurring in freshwater rather than the marine environments [ 86 , 87 ]. Most green algae are microscopic, except for a small number of species in some specific genera such as those in Cladophora which are multicellular and macroscopic [ 87 , 88 , 89 ]. The unicellular genera Chlamydomonas and Chlorella are some common examples of green algae in both marine and freshwater ecosystems worldwide, which consist of species that disperse in a wide range of habitats [ 90 ].…”

Massive Ulva Green Tides Caused by Inhibition of Biomass Allocation to Sporulation

“…Ulva is a promising organism for carbon dioxide fixation and bioproduct production due to its high productivity [51,52]. Understanding the allocation system of vegetative growth and sporulation decay will enable greater control of biomass production and will contribute to the development of the bioeconomy.…”

Rosmarinic Acid and Ulvan from Terrestrial and Marine Sources in Anti-Microbial Bionanosystems and Biomaterials

“…Ulva is an abundant and ubiquitous green macroalgae, proposed as a model system with phenotypic plasticity [39,40]. The genus Ulva is adapted to various environmental conditions and could be wild-harvested or cultivated regarding ulvan extraction [41][42][43]. The extraction of the polymer occurs from many different locations around the world, including the species: U. rotundata [44], U. armoricana [44,45], U. rigida [46,47], U. clathrata [48], U. fasciata [49][50][51][52], U. intestinalis [53], U. ohnoi [54,55], U. lactuca [56][57][58], U. pertusa [59], and many others.…”

“…Despite the dominance of red and brown seaweed production, the particular interest of Ulva is due to its fast growth rates and high ulvan carbohydrate content [40,60]. Consequently, the biomass of the Ulva species is emerging as a sustainable raw material, with increasing commercial importance and diversification for the bioeconomy [43].…”