Seaweeds Against Climate Change: How Algae Provide Us with Ecosystem Services

Featured Image Caption: There are three main types of seaweeds: green seaweeds (or Chlorophytes), brown seaweeds (or Phaeophytes), and red seaweeds (or Rhodophytes). They all serve a purpose in aquatic ecosystems. (Image Source:Seaweed-2019-358” by Windell Oskay, licensed under CC BY 2.0).

Reference: Cotas, J., Gomes, L., Pacheco, D., & Pereira, L. (2023). Ecosystem Services Provided by Seaweeds. Hydrobiology.

We can all agree that seaweed is a bit annoying, right? If you’ve ever been to the beach and stepped in a patch of seaweed you must know how uncomfortable it is to share our space with it, and sometimes it might even be hard to remember that we are actually coming into its environment. We are the intruders in the aquatic ecosystems they inhabit. What is seaweed anyways? Seaweed is a general term used to describe macroscopic algae, or, in other words, algae that we can see with our own eyes. Seaweed, like the terrestrial plants we are more familiar with, are primary producers, and therefore are at the bottom of the marine food chain. All types of seaweed require two conditions: salty water and sunlight. Without these conditions, seaweed can’t thrive.

Image Caption: Scientist studying and classifying seaweeds in an intertidal zone. (Image Source:Seaweed-2019-370” by Windell Oskay, licensed under CC BY 2.0).

But what makes seaweeds so interesting is the wide range of positive roles that they play in the environment and our lives. Seaweeds don’t only serve as a shelter for marine species, but marine species also use seaweed as a food source. And beyond that, marine species aren’t the only ones who use seaweed as a food source—so do we, and not only for sushi. Seaweed is widely used as feed for farm animals and as fertilizer in agriculture. It is also an important component in medicine and some processed foods.

What Are Ecosystem Services?

Ecosystem services are the direct or indirect ways in which ecosystems contribute to human wellbeing. These can be classified into supporting services, regulating services, provisioning services, and cultural services. Supporting services are those functions that are inherent to the survival of the species being studied, but nonetheless provide support indirectly to the ecosystem as a whole and ultimately represent a gain for the human population, like photosynthesis providing energy for plants and oxygen for the whole ecosystem without that gain being its intended goal. Regulating services are those that arise from the regulation of ecosystem processes, like erosion regulation or disease and pest regulation. Provisioning services are those that describe resources that can be directly obtained from the ecosystem, like food and fibers. And lastly, cultural services are nonmaterial benefits we obtain from ecosystems, like being able to partake in ecotourism because of these components within an ecosystem.

Image Caption: Many animals use seaweed not only for food, but for shelter as well. (Image Source: “Seaweed-2019-354” (left) and “Seaweed-2019-352” (right) by Windell Oskay, licensed under CC BY 2.0).

In the past decade, ecosystem services have held the spotlight in environmental science research and policy as these attributes can help us define which species we should make an extra effort to protect and restore. In some countries, the government has even paid citizens for protecting these ecosystem services, as a way to incentivize their conservation and rehabilitation.

Ecosystem Services Provided by Seaweed

In their paper, João Cotas and their collaborators explore more than 20 ecosystem services that seaweed have to offer.

Some of the supporting services these researchers highlighted are marine soil formation (which increases environmental quality for aquatic plants), photosynthesis (which produces oxygen and plant biomass), primary production (which produces biomass for organisms higher in the food chain), the production of oxygen (which provides fish and other organisms humans use with a suitable habitat), and providing shelter for other organisms (which facilitates the conservation of biodiversity).

Some of the regulating services that seaweed provides include erosion regulation (serving as coastal and shore protection and improving water quality), water purification (which they achieve as they reduce nutrients and pollutants, enhancing water quality), and disease prevention (as the improvement of water quality leads to a decrease in pathogens in said water).

The researchers also highlighted provisioning services, like how seaweed provides us with food (both for human consumption and for other uses), fibers (used in a variety of products), and biochemicals, natural medicines, and pharmaceuticals (like the use of active components like alginate, carrageenan, and fucoidan which have been used for the prevention of cardiovascular disease, the treatment of type-2 diabetes, and the treatment of viral infections).

Finally, some of the cultural services showcased were how seaweed holds educational value (benefiting human development and critical thinking), are used for recreation and ecotourism (which serves as an economic incentive to protect seaweed), and it holds cultural heritage values, involving local knowledge systems and spiritual and religious services, all of which benefit us as a multicultural society.

For these, and many more reasons, we are called to fight for the oceans and protect our seaweed, as annoying and inconvenient as it may be.

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Andrea Valcarcel

Having graduated with a Bachelor of Science degree in Animal Biology from Thompson Rivers University (BC, Canada), I am currently working as the head of an Oceanic Lab in the Dominican Republic while also being an MSc candidate in Ecology and Environmental Sciences. My research so far has been mostly focused on corals and marine mammals and the effects climate change may have in their overall behavior and survival. When not monitoring marine ecosystems, you can find me volunteering with my therapy dog and reading romance and fantasy novels. Twitter: @andreavalcar

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