Turning the Tide: Harnessing Ulva Biomasses in the Mediterranean from Problem to Opportunity

The proliferation of Ulva genus macroalgae in the Mediterranean reflects the dual forces of eutrophication and climate change. Historically scattered, these organisms now thrive in abundance, transforming the delicate balance of marine ecosystems. Eutrophication, driven by nutrient runoff from human activities, provides a fertile breeding ground for Ulva, while rising sea temperatures and altered ocean currents due to climate change further facilitate their expansion. This expansion leads to Ulva thalli outcompeting native species, disrupting food webs, and smothering fragile habitats, ultimately jeopardizing biodiversity and undermining the resilience of marine environments. The dense mats formed by Ulva can impede recreational activities such as swimming, boating, and fishing, affecting both locals and tourists. Additionally, the excessive growth of Ulva can exacerbate anoxic conditions in marine environments, leading to the depletion of oxygen levels crucial for supporting marine life. Effective management strategies are essential to mitigate the adverse effects of Ulva proliferation and ensure the sustainability of coastal ecosystems. A promising management strategy involves exploring the potential of Ulva in various sectors, such as pharmaceuticals, food, and feed industries. This approach not only transforms Ulva from waste to a resource but also views it through the lens of biorefinery. Extracts derived from Ulva can be utilized for their pharmacological properties, including antibiofilm activity and immunomodulatory effects. By harnessing these properties, Ulva-based products could find applications in pharmaceutical formulations aimed at contrasting bacterial infections or modulating immune responses. Additionally, Ulva extracts can be incorporated into food and feed products to enhance nutritional value or provide functional benefits. The cultivation of Ulva is also beginning in the Mediterranean through Integrated Multi-Trophic Aquaculture (IMTA) with fishes and mollusks. Extracts containing ulvans can be utilized in cosmetics and nutraceuticals, and these species can be used as food, even in Italy. In agricultural use, Ulva exhibits various biostimulant effects and accentuated plant growth regulator (PGR) contents. Research is exploring new extraction methods, such as microwave utilization and ultrasound extractions, to enhance performance and environmental friendliness. The Mediterranean region, known for its diverse biodiversity and increasing environmental pressures, has seen a shift in perspective regarding Ulva algae. Once considered a nuisance, Ulva is now seen as a valuable resource due to growing awareness of marine ecosystems' importance, technological advances, and socioeconomic factors. Ulva biomass, previously discarded, can now be utilized for various purposes. Sustainable management of marine resources, environmental quality, and multi-stakeholder collaboration are essential. This work provides a preliminary insight into the topic, promising further exploration of how Ulva biomass utilization can contribute to a more sustainable future in the Mediterranean.