Algae
Algae

Algae

Tags
đź“Ś
Meet our investment in this space: BettaF!sh

TL;DR

Algae are aquatic, plant-like, organisms that are an essential part of our climate system. Because algae are fast-growing and cover more surface area, they are much more efficient than trees at removing CO2 from our atmosphere. Algae can be farmed for commercial uses or "sunk" into the deep ocean, trapping the carbon for thousands of years.

đź’ˇ
Research is still needed around the environmental impacts of enhancing the natural CO2 drawdown of algae, and regulation will need to catch up with the growth of the industry.

What are algae?

Algae are aquatic organisms from two groups: macroalgae (aka seaweed) and microalgae (aka phytoplankton). Scientists estimate there might be more than 1 million different species of algae out there and each one possesses different, often valuable, qualities. Algae has also been called a "secret weapon" against climate change.

Microalgae - Phytoplankton

Source:
Source: What are Phytoplankton?

80% of all algae are microalgae: single-celled organisms found in the upper layers of fresh and saltwater environments because, like plants, they need sunlight, nutrients, and CO2 to live and grow. During the day, microalgae draw down CO2 and give off oxygen (actually 50 to 80% of our oxygen comes from algae).

Nutrient pollution, from things like agricultural runoff, can speed up microalgae growth and cause harmful algal blooms. As the algae die, oxygen is removed from the water, creating a "dead zone" that wipes out all plant and animal life in the area. Certain species will even give off toxins that make the water unsafe, possibly deadly, for people and land animals.

Microalgae cultivation

Microalgae can be grown in areas where agriculture isn't possible and without using fresh water but requires significant amounts of fertilizer. There are two types of microalgae cultivation: open and closed.

Carbon capture potential

Microalgae drive the "biological carbon pump" that is responsible for sequestering about 10 gigatons of carbon in the deep ocean every year. It has been proposed that adding nutrients (like iron and rock dust) to the ocean is an effective way to increase microalgae production and draw down even more CO2.

"If you give me half a tanker of iron, I can return you an ice age." - John Martin, Marine Observation Station

There are some questions about how useful macroalgae (seaweed) is at capturing carbon because many studies have not looked at how much CO2 is released by the organisms supported by seaweed. This “net ecosystem production” might mean that seaweed ecosystems are a source, rather than a sink for CO2, essentially because the increase in seaweed enhances the food web—bringing in more fish that breath out CO2. This does not mean we give up on seaweed, because it is likely still better than the alternatives, but this is something we should keep in mind when planning aquaculture projects.

Commercial uses for microalgae*

Human consumption

  • Human food: Adding microalgae to food products can increase nutritional benefits, improve texture and quality, and reduce spoilage.
  • Cosmetics: When microalgae are exposed to harsh conditions, they develop ways to become resistant and the products of those reactions are of interest to the cosmetics industry. Microalgae is used in makeup as well as products for anti-aging, sun protection, blemish prevention, moisturization, and skin whitening.

Biofuel

  • Theoretically, microalgae can produce carbon-neutral fuel alternatives for internal combustion engines and electricity generation that don't compete with food systems. Although algae can grow very fast and in harsh environments, it doesn't currently scale for this purpose.
    • "Meeting just 10% of Europe’s fuel demand with unmodified algae would require flooding three Belgiums in more than 7 inches of water while using 50% of the fertilizer used for European agriculture..." - Professor Kevin Flynn, U.K.’s Plymouth Marine Laboratory (WSJ, 2021)

    The microalgae produced for biofuel can also be used as a substitute for petroleum in other products.

Other uses

Macroalgae - Seaweed

Seaweed = three types of macroalgae (classified by the dominant pigment they produce) found in marine (saltwater) environments

Red macroalgae

source
source
  • ~6,200 types
  • example: nori
  • grows at deepest depths
  • highest protein (13-40%)

Brown macroalgae

source
source
  • ~1,800 types
  • example: kelp
  • largest in size
  • contain the most iodine

Green macroalgae

source
source
  • ~1,800 types
  • example: aonori
  • only grows in shallow water

Carbon capture potential

Seaweeds are good at capturing CO2 because they generate more organic material than gets used up within their ecosystems. Globally, wild seaweed sequesters about 173 million tons of carbon every year, and farmed seaweed could potentially trap another 6.8 million tons of carbon (equivalent to 2.48 million tons of CO2).

  • The cost per ton of CO2 varies by species, region, and size of the farm. It can be as low as $71/ton or as high as $27,000/ton (median is $543/ton). Costs are likely to go down as the industry develops.
Source:
Source: How Kelp Naturally Combats Global Climate Change

Seaweed cultivation

Seaweed needs: enough nutrients + correct temperature + light + salinity

Seaweeds can grow more than 30x faster than land plants, but their potential is limited by where they can be grown and it's possible that climate change will actually decrease suitable areas. The seaweed cultivation market is predicted to reach $30.2 billion by 2025 (up from $16.7 billion in 2020), with Europe projected to have the highest growth.

Source:
Source: Can Seaweed Farming Reverse Climate Change?

Seaweed can be cultivated in open water or in land-based facilities (like ponds or artificial tanks). Land facilities can have high infrastructure and energy costs but cultivation is often year-round, it is easier to control the environment, and there is less risk of negative environmental consequences.

Offshore farming can expand seaweed farming areas but is not without its challenges. The open ocean environment is harsher and more exposed than close to the coast, so it requires a lot of monitoring. Costs and energy requirements can be higher due to the need for frequent transportation to and from the crops.

  • Sea6 Energy (India/Indonesia) has claimed to develop the world's first open-ocean, mechanized seaweed farming operating system.
Source:
Source: Seaweed for Europe

Marine conditions can be very different from place to place, even within a few meters or centimeters. The same species of seaweed will adapt very differently based on their environment.

Source:
Source: Pegasus - Phycomorph European Guideline for a Sustainable Aquaculture of Seaweeds

Co-benefits of seaweed farming

  • Protect coasts from erosion by dampening the effects of waves.
  • Removing excess nitrogen and phosphorous that runoff from agriculture and preventing harmful algal blooms.
  • May protect shellfish from ocean acidification (photosynthesis reduces CO2 concentrations in that area and raises the pH). It is important to note that this protection disappears when that seaweed is harvested.
  • May help marine creatures adapt to warmer water by providing an oxygen-rich habitat. This is because the seaweed is harvested before it has a chance to break down (when that happens, the process removes oxygen from the water and releases CO2).

Consequences of seaweed farming

  • Introducing non-native species can have unforeseen consequences on wild marine organisms (both at the farm and if the seaweed escapes and populates in other areas, i.e. becomes an invasive species).
  • Seaweed absorbs heavy metals and bacteria like E. coli, so if the end-product is food-based the location must be closely monitored. This also increases the chance that escaped seaweed could spread parasites and pathogens which can also accumulate in other organisms that humans consume.
  • May reduce seagrass habitat by cutting off light access. Seagrass is one of the biggest carbon sinks in the ocean (accounting for 10-18% of all carbon buried).

We have seaweed, what now?*

Production of seaweed more than tripled between 2010 and 2018 (from 10.6 to 32.4 million tons) and about 97% is farmed (the rest is wild-collected).

Use it (sell the seaweed)

77% of seaweed produced is used for human consumption (food, medicine, and cosmetics). A large driver of seaweed growth over the past decade has been for carrageenan (food additive, vegan substitute for gelatin).

Seaweed has the potential to reduce emissions from its end-use. This includes replacing plastic packaging and as an animal feed additive (has been shown to reduce methane emissions from cattle).

Sink it (sell offsets)

In order to remove carbon from circulation, seaweeds would need to be sunk in ocean waters with depths greater than 1,000m. Looking at kelp (which grows in depth of less than 30m), up to 22% has the potential to reach the deep ocean on its own, so it needs assistance to sink deep enough to trap that carbon.

  • Urchin poop. Urchin grazing can destroy entire kelp forests, but their poop actually makes it so the material can travel further distances (urchin poop sinks 20x slower than whole plants).

More on seaweed as a food source

  • Plant-based diets are more sustainable than meat, however, with rising populations, the increased conversion of land over to agriculture is driving up emissions.
  • Seaweed is high in amino acids, minerals and vitamins—some species of red seaweed even contain up to 40% protein and have been identified as having the potential to develop low-cost, nutrient-rich, diets that can compete with current crop-based sources of protein like the soya bean.
  • The shelf-life and overall quality of foods can be improved through the addition of either seaweeds or seaweed extracts. Beyond nutritional value, these additives have potential as antioxidants, antimicrobials, preservatives, and emulsifiers in everything from baked goods to beef and pork products.
  • Seaweed's high fiber content has been found to promote digestive health and even reduce the risk of colorectal cancer. For example, sodium alginate (a natural polysaccharide found in brown algae) can have reparative and inflammation suppressing effects on the stomach.
  • Seaweeds contain Omega-3 which we otherwise source from fish, however, fish do not create these heart-healthy nutrients by themselves—they get them by eating algae. By eating the plants fish eat, humans get the same benefits while reducing pressure on fish stocks.

Concerns over seaweed as a food source:

  • Because of human activity (mainly industrial), the concentrations of toxic elements like arsenic, cadmium, mercury, lead, and antimony have risen in aquatic environments. Since seaweeds will absorb whatever elements are present in their environment, water quality monitoring is important.

Regulations around seaweed aquaculture

  • The Nagoya Protocol: A UN treaty around biological diversity; offshore seaweeds could be considered as being located in areas beyond national jurisdictions.
  • Europe: There are no Europe-wide regulations specifically for farming seaweed, but many apply to seaweed and licenses need to be obtained at the country level. Additional regulations may apply based on the intended end-use (i.e. product safety for food, cosmetics, etc.).
    • Some examples:
      • Habitats Directive (EEC): aquaculture should be compatible with natural habitats.
      • Marine Strategy Framework Directive (EC): aquaculture should not negatively affect biodiversity or contribute to invasive species.
      • Water Framework Directive (EC): aquaculture should not negatively affect biodiversity.
      • Maritime Spatial Planning Directive (EU): aquaculture should not interfere with other maritime activities.
    • Seaweed for Europe’s Licensing Toolkit: Offers tips for how to get a seaweed farming license in Norway, Denmark, Scotland, Ireland, England, and France.
  • United States: Regulations are up to the state and vary widely. At the federal level, FDA guidelines apply only to seaweed grown as a food product.