Microalgae

According to a new study Microalgae appear to rely on a unique strategy to cope up with the global warming.

Microalgae:

• They are unicellular organisms that can grow in aquatic environments and use light and carbon dioxide (CO2) to create biomass.
• They contain lipids and fatty acids as membrane components, storage products, metabolites, and sources of energy.
• They may exist individually, or in chains or groups.
• Unlike plants they do not have roots, stems, or leaves.
• They are capable of performing photosynthesis, and hence are important for life on earth as they produce approximately half of the atmospheric oxygen.
• Microalgae, together with bacteria, form the base of the food web and provide energy for all the trophic levels above them.

Key highlight of the study:

• As climate change reduces the availability of nutrients in the sea, marine microalgae increase production of a protein called rhodopsin.
  • It is related to the protein in the human eye responsible for vision in dim light.
• This light-responsive protein is helping the microalgae flourish with the help of sunlight in place of traditional chlorophyll.
• Microbial rhodopsin is proposed to be major light capturers in the ocean.
  • They may absorb as much light as chlorophyll-based photosynthesis in the sea, which also captures light to generate energy and food.

Coping with global warming:

• The warmer the surface water gets, the lower are the nutrients in these surface water layers leading to less mixing between the surface waters and nutrient-rich deeper waters as the oceans warm.
• The nutrients become scarce at the surface, impacting the primary producers such as microalgae that are present in the top layer.
• Algae starve and, therefore, produce less food and capture less carbon dioxide from the atmosphere.

Role of Rhodopsins:

• Rhodopsins were found to be more concentrated in low latitudes, where there is less mixing of ocean waters and lower concentrations of nutrients, including dissolved iron.
• For algae to produce food and to remove carbon dioxide from the atmosphere, they need sunlight and to harness sunlight, the microalgae require a lot of iron.
• However, 35% of the surface of the ocean does not have enough iron to support the growth of algae.
• This is particularly relevant for the Southern Ocean, which is the largest iron-limited aquatic ecosystem.
• But they are home to the largest populations of consumers such as krill, fish, penguins and whales, which depend on primary producers such as microalgae.
• These findings, have the potential to reduce the negative effects of changing environmental conditions, such as ocean warming and even the reduction in the productivity of crops
• The same mechanism could be deployed to enhance the activity of microbes that cannot use light, such as yeast.

Ref: Source