We are currently testing macroalgae cultivation across various sites in the Venetian lagoon, Italy. Our challenge has been to identify the species that are growing naturally, and then assess which of these types of algae are best for the environment, and which provide opportunities for bioproduct creation. The type of bioproduct that can be made depends on the species of algae that grows most effectively, and the properties that make up the algae.
One of the species we are cultivating is Ulva! It is commonly known as "sea lettuce." This type of algae has promising cultivation potential within Venice. It can greatly benefit the environment due to its rapid growth rate and ability to trap heavy metals and microplastics that pollute the lagoon or other waters.
Picture of Ulva in the Venetian lagoon
Our first round of testing shows that the biomass has doubled each week, and by introducing it to the cultivation area, we have immediately witnessed a significant increase in biodiversity around the farming structure.
We are monitoring the data carefully and continually to ensure that growth is not too rapid and it is controlled in order to minimise any potentially negative, unintended environmental impact(s). The key to sustainable growth is to ensure that cultivation is performed safely and conscientiously, based on a firm scientific foundation of research.
Just like other types of macroalgae this species can also be turned into a variety of bioproducts that can help reduce the need for harmful fossil fuels.
Why Ulva Species?
Promising Cultivation Potential
The macroalgae species Ulva Lactuca, commonly known as green sea lettuce, has great potential for macroalgae farming.
Over the last ten years there has been growing interest in the cultivation of this species due to its rapid growth rate and wide environmental tolerance towards factors such as: temperature, salinity, eutrophication, and pH (Steinhagen et al., 2022).
This type of macroalgae can live in water that is near coastal areas that have a water depth from 1-2 meters. (Buck & Shpigel, 2023) , and have been shown to multiply and thrive “when nutrient-rich wastewater from agricultural or densely populated areas is flushed into the sea” (Wichard, 2023). Wastewater acts as a fertilizer for these species, helping to promote algal growth (Wichard, 2023).
Ulva Species Cultivation
Environmental Benefits
Ulva has the potential to be cultivated both on land and in the sea to harvest biomass (Buck & Shpigel, 2023). Harvested biomass can be used for various purposes such as bioenergy and biomaterial production. The high growth rate sees the percentage of biomass increasing by up to 30% per day through the absorption of nutrients from seawater. This high growth rate shows a huge potential application for bioremediation, reducing heavy metal pollution and ocean acidification through absorption of metals and carbon dioxide by algal blooms (Simon et al., 2022).
Additionally, Ulva has potential to trap plastics and research in the Yellow Sea has shown that Ulva cultivation traps approximately 35.6 tons/year of microplastics (Gao et al., 2020).
Environmental Risks
The decomposition of Ulva lactuca can produce acidic vapors that are harmful to both animals and humans. When uncontrolled, the rapid growth of Ulva species can also lead to a decrease in biodiversity, as well as invading local beaches. However when grown in a controlled environment and with close monitoring and maintenance, these risks can be mitigated.
Potential Bioproducts
Ulva has high concentrations of phosphorus and can be converted into a biofuel source (Simon et al., 2022).
Ulva's biomass also has the potential to be converted into bioethanol because of its physical makeup being 50% carbohydrates (Simon et al., 2022).
These fuels can be utilized by industries as a replacement for fossil fuels through entire production supply chains to help mitigate climate change (Peter et al., 2024).
Comments