Phytoplankton are single-celled organisms that mostly live in lakes and oceans and are known to make their own food using the process of photosynthesis. Algae too convert the sunlight into energy using photosynthesis but they cover a great diversity of organisms that range from microscopic cyanobacteria to giant kelp. And so, not all algae are phytoplankton, but all phytoplankton are considered algae. Let us find out more about them and how they impact the aquatic ecosystems and can improve the dynamics of biofuels.
Phytoplankton are free-floating organisms that move with the current of the water. The main categories of phytoplankton include cyanobacteria, dinoflagellates, and diatoms. Dinoflagellates can control their movements using flagella and they don’t drift away with the water current. Phytoplankton uses carbon dioxide and releases oxygen, thereby converting minerals to a form that can be used by the aquatic animals of the water body. Oceanic phytoplankton is also the main source of food for most of the sea organisms ranging from zooplankton to other types of invertebrates and small fishes. Phytoplankton are known to thrive when the levels of carbon dioxide in the water body rise and increase its acidity. The researchers say that phytoplankton help to reduce the intake of carbon dioxide by the ocean and thus help in regulating the climate worldwide by absorbing the gas which would otherwise heat up the atmosphere.
Impact of Phytoplankton
Even though phytoplankton is the foundation of the aquatic food web and is the primary producer that feed all the aquatic life, they can also have a disastrous effect on the marine life. Certain types of phytoplankton are known to cause mass mortality in the ocean or lakes and cause ‘toxic algal bloom’ or ‘red-rides’. If there is an overgrowth of phytoplankton, they produce powerful biotoxins that can kill marine life that feeds on the phytoplankton. It can also have serious effects on people who may eat this contaminated seafood. As a toxic algal bloom occurs, dead phytoplankton sink to the bottom of the ocean or the lake. The bacteria that decompose the phytoplankton drain the oxygen from the water, thereby choking the marine life and resulting in a dead zone.
Now lets us look at how algal biofuels can be one of the most sustainable sources of biomass and source of fuel and other products:
Importance of Algal Biofuels
Algae are a logical source from which biodiesels can be made as the oil that can be found inside the algae cells is a lot similar to oils that can be found in vegetables like rapeseed, soy, and canola. There are more than 1,00,000 genetically diverse strains of algae that the researchers worldwide can study and develop promising algal biofuels and bioproducts. Algae can be cultivated on land that is not otherwise suitable for traditional agriculture and also water bodies that cannot be used for other crops, including brackish and wastewater. Thus algae biofuels can complement the biofuels made using other traditional sources of agriculture. As algae thrive in nutrient-rich wastewaters, it can simultaneously purify these wastes while producing biomass.
Biofuel from algae may be produced from seaweeds through photoautotrophic methods or through heterotrophic methods. Phototrophic methods require light for the algae to grow and produce biomass whereas, in the case of heterotrophic methods, algae are grown without light and are made to feed on carbon sources like sugars to create biomass. In heterotrophic fermentation processes, hydrogen, ethanol, methane, and other alkenes can be directly produced by the algae. By using both the phototrophic and heterotrophic processes, algae biomass can be converted into different types of biofuels like biodiesel, biogasoline, ethanol, and jet fuel. Production of algal biofuels does not lessen the carbon dioxide levels in the atmosphere as when these biofuels are burned, they return the carbon dioxide taken out of the atmosphere. High oil prices and world food crisis are driving the big agencies to farm algae for making biofuels using wastewaters and lands that are not suitable for traditional agriculture. The International Energy Agency predicts that biofuels will contribute 6% of total fuel use by the year 2030.
Benefits of Algal Biofuels
- Algae grow faster than the traditional crops and can produce higher volumes of biomass and biofuels.
- Algae have high biofuel yields as they store the energy in the form of oil and carbohydrates. They can produce anywhere between 2,000 and 5,000 gallons of biofuels per acre every year.
- After the oil has been extracted from the algae, the left-over algal biomass can still be used by drying and pelletizing it and using it for other power generation sources.
- The Algae Industry is helping create a large number of jobs throughout the US. The Algal Biomass Organization estimates the creation of 2,20,000 jobs in this sector by the year 2020.