The third edition of the Festival of Marine Forests took place at the end of May. The programme consisted of 30 individual events, including guided tours, lectures, boat trips and workshops. My wife Monique and I decided to attend two events: ‘Discovering the Martinhal Lagoon’ and ‘How to make watercolours from soil’.
The walking tour around the lagoon was led by university professors and marine biologists Duarte Falde and Ester Serrao. Our small group, comprising about 15 people, was mostly made up of students from the University of Algarve in Faro.
Our learned experts identified several different algae and sea grasses and explained their benefits or detrimental effects to the environment. Algae come in two varieties: macroalgae and microalgae. The former includes species of seaweeds and larger growth specimens found on the seashore, while the latter are found in a variety of environments, specifically in our case, the Martinhal Lagoon.
The Role of Algae
Algae play a critical role in local ecosystems by converting carbon dioxide into life-sustaining oxygen. It’s estimated that algae convert nearly 50% of the Earth’s carbon dioxide into oxygen, providing us with the very air we breathe. Scientists worldwide are decrying the destruction of the planet’s forests, which play a crucial role in absorbing carbon dioxide and converting it into oxygen. In fact, trees and rainforests produce approximately 28% of the oxygen on Earth; the other 72% comes from plant life in the ocean.
Ester showed us a sample of the red alga, agar. It cultivates a type of bacteria important in microbiology. It has gelatinous properties and is used in vegetarian foods, the pharmaceutical industry, and as a natural dye. At one time it was harvested, but Morocco has an abundance and has made the relatively small amount in the Algarve uneconomical to market.
As we continued around the lagoon, we saw other algae, a marine succulent, glaucous glasswort and a marine grass, edible to birds, with some varieties even supporting organisms like small worms.
The most striking observation was the algae bloom. Normally, the green algae are healthy, but when millions of microscopic plankton multiply rapidly, they use all of the oxygen in the water, then produce toxins and harm other marine life. This can be exacerbated by excessive nutrients entering the water, caused by fertilisers or runoff from nearby villas or hotels. When the water level drops due to evaporation and the drying up of the stream that feeds it, the dead algae turn white and then black and hang from small bushes and foliage, giving a surreal appearance.
Invasive species
We continued on and came to an area where locals dump their garden refuse and here Duarte pointed out some invasive plants, a cactus, a cobra lily and even a tuft of Kikuyu grass that is often used for lawns and golf courses but can quickly spread if not controlled.
The trail led us to a patch of thread-thin grass growing alongside barley grass, which is an annual. In other words, it comes and goes on a yearly basis, but it leaves behind enough seeds to propagate again in the following season.
Finally, we returned to our starting point and in the hotel grounds, we saw a full flower bed of the invasive Pennisetum. It makes an attractive ‘fountain’ display with feather-duster-like plumes, but it proliferates aggressively. We saw where it had encroached towards the lagoon and Duarte was adamant that it was illegal to plant. Even so, it is available for purchase in many garden centres in the Algarve.
Before departing for our next adventure, we had a group photograph to celebrate nature in the 2000s. Many thanks to the Vila do Bispo Council and the University of the Algarve, the organisers and our guides, Duarte Falde and Ester Serrão.
Did you know?
Invasive plants are non-native plant species. They are introduced either accidentally or intentionally. They can displace native flora, alter soil chemistry, and/or reduce water content in the soil. They can reduce plant diversity, which may affect food supplies for birds and other wildlife. Some species, like eucalyptus, can increase fire hazard and some may impact human health, as in the case of allergies.
On the positive side, species may be introduced for food, erosion control, or for decorative purposes.
