Humain Practicies Implementation

Significance of our project in France

The main objective of our project is to find new applications and add value to green algae, more specifically Ulva Spp., that is washed up on the beaches of the region of Brittany in France. These green algae form green tides that appear more and more every year on our coastline, but also in many other parts of the world.

Indeed, hundreds of articles about this disaster are published each year, and we often hear about this phenomenon on the news. The increase in the occurrence of green tides is a real public health and socio-economic issue.

Fig 1 : Average surface covered by green algae in Brittany over the period 2007-2018. NB: 1 hectare = 2.5 acres [1]

As the algae dry, they form a hermetic crust and an anoxia zone develops which allows the development of anaerobic bacteria, including sulphate-reducing bacteria (SRBs). This bacteria is responsible for the production of hydrogen sulphide (H2S), an extremely harmful gas that can be fatal for many species, including humans.

Moreover, their presence is detrimental to the economic dynamics of regions for which beaches are a major tourist attraction.

At the moment, there are no relevant solutions to the accumulation of these Ulva Spp. algae. Municipalities still rely on costly and time-consuming collection, and only few recovery initiatives exist.

.. But also on a worldwide scale

One of the reasons we choose our project is because of the regional aspect, but we can easily apply our ideas in many other places in the world.

Indeed, the green tide phenomena observed in France exist on an international level. Similar situations linked to the uncontrolled development of microalgae with harmful effects can be found in places like China, Denmark, Ireland, Italy and the United States.


Our project in figures

Anthropogenic activities are causing many changes in ecosystems. According to CEVA (Centre for the Study and Valorisation of Algae) [2], green tides are one of the most notable manifestations of these environmental changes.

This phenomenon depends on the amount of nitrates present in the land, but it is not the only factor involved. Indeed, Sylvain Ballu, who has been working on green tides for years, explains:

"On one hand, this phenomenon depends on the quantity of algae that proliferated the year before the and on the other hand on weather factors (storms, swell, sun, etc.) which favours the growth of these ulvae [3]"

To give an example from around the world, in 2008, Jiaozhou Bay in China experienced an impressive bloom of 20 million tonnes of Ulva spp. covering 30,000 km2 [4] [5] [6]

A scientific process to respond to the local problem

The aim of our project is therefore to valorise the algae Ulva spp. By using enzymes to degrade ulvane (the main component of the wall of these algae) we can collect sulphur.

This sulphur, as well as the waste products of the degradation process, could be used in various sectors such as food processing or pharmacology.

Sulphur is known for its many uses in the chemical industry, and therefore represents an interesting substance to valorise.


Our project involves certain risks, especially in the experimentation part, and therefore requires a strict application of safety rules. Indeed, we manipulate dangerous products such as H2S or sulphuric acid, requiring the application of a rigorous protocol.

For the safety protocol, please refer to the Safety page

Beyond the risks occurring during laboratory manipulations, it is important for us to carry out prevention on the potential dangers represented by green tides, as much on the biological risk as on environmental and social-economic issues.

This prevention concerns our work in Human Practice.


Our project is dedicated to different end-users. First, by proposing a solution to the accumulation of these algae, we could help municipalities who could then work with industries or laboratories. This phenomenon could then benefit financially to the affected municipalities. We know that millions of euros are spent each year on collecting green algae.

In addition to this economic issue, there is a logistical issue. In Brittany, there is only one algae treatment station, which means that all the algae from the beaches are collected in one place. The algae are then spread on agricultural land. However, this spreading can only be done once every five years in order to protect the soil.

Laboratories and industries could then trade or use the sulphur and degradation products. This would be an economical gain.

Many research studies have shown that relevant molecules are present in Ulva spp. like minerals, carbohydrates, lipids, proteins and vitamins. Algae not used in degradation could therefore be used for nutritional, pharmaceutical or cosmetic purposes. The energy resources sector is also looking for a future for these algae, which would therefore be a new opportunity.

How do we see the future of our project?

If our project were to become a reality on a larger scale, the regions affected by green tides could become major actors. There are already research laboratories working on these species of algae, and we could offer them the remaining biomass.

Our project could allow Brittany to grow economically and even create new jobs.

Moreover, by changing the enzymes used in our experiments, we could then use other algae such as brown algae and red algae, which would give a new twist to our project. This way, we will no longer restrict ourselves to the beaches of Brittany.

International outreach

By touching other species of algae, we are opening up internationally and proposing a turn-key project for other affected regions such as China.

We remind you that this project is not a definitive solution against green tides and that the reflection on a solution to their occurrence should be considered. However, our project proposes an innovative alternative to counter this harmful phenomenon.


  • [1] - OBSERVATOIRE DE L’ENVIRONNEMENT EN BRETAGNE, 2020. Average area covered by green algae over the period 2002 - 2019 [online]. 2020, April. S.l. : s.n. [Accessed on October 16, 2021]. Article Link
  • [2] ANON, 2021. Green Algae: encouraging results in 2020, but caution is still required. In: France 3 Bretagne [online]. 10 February 2021. [Accessed on 28 September 2021]. Article Link
  • [3] MOSSER, Véronique, 2021. Des tapis d’algues vertes envahissent l’Odet. In: [online]. 14 July 2021. [Accessed 16 October 2021]. Article Link
  • [4] IGEM NANTES, 2020. Implementation - iGEM Nantes. In: iGEM Nantes [online]. November 2020. [Accessed 16 October 2021]. Article Link
  • [5] Ye N.-H. , X.-W. Zhang, Y.-Z. Mao, C.-W. Liang, D. Xu, J. Zou, Z.-M. Zhuang and Q.-Y. Wang. Green tides are overwhelming the coastline of our blue planet: taking the world largest example. Ecological research, 26: 477–485, 2011.
  • [6] Gao S., X. Chen, Q. Yi, G. Wang, G. Pan, A. Lin and G. Peng. A strategy for the proliferation of Ulva prolifera, main causative species of green tides, with formation of sporangia by fragmentation. PLoS ONE, 5: e8571, 2010.