Marine microbiology is quickly emerging as one of the most exciting and fast-moving areas of modern science. Scientists and researchers worldwide are devoting themselves to understand and get more details about the roles of microbes in ocean processes, their interactions with other aquatic life, and the overall impact of these microbes on the maintenance of Earth. With every step towards better technology, we have better tools that aid our scientists today like remote sensing, molecular biology, and deep-sea explorations. Studying the role of microbes is providing helpful insights into the food web, symbiosis, and other such related concepts. Let’s delve deeper and understand why microbes are so important.
Microbes are those organisms that are so small in size that they are not visible to the naked eye and have to be seen using a microscope. They are everywhere, and often in huge numbers. One litre of coastal seawater alone can contain billions of such microorganisms which include different types. Microbes make up 98% of the biomass of the oceans of the world. At the broadest level, they can be categorized into the following three types:
- Bacteria: Bacteria are quite diverse in their nature and can be scientifically classified into 19 major groups on the basis of their shape, cell structure, metabolic functions, and strain properties.
- Archaea: Archaea are single-celled organisms that resemble bacteria but are actually in a different biological domain. These microbes may comprise up to half the mass of life in the oceans. They were originally discovered in extreme environmental environments such as highly saline or acidic environments, terrestrial hot springs, but on some more research years later, they were also found to be living in freshwater and saltwater environments.
- Eukaryotes: Any organism with a clearly defined nucleus is classified as a eukaryote. This group of microbes includes animals, plants, fungi, protists, and algae. Eukaryotes are said to have evolved almost as early as 1.9 billion years ago.
What Do Marine Microbes Do?
Most microbes live in extremely organized and interactive communities that can be quite difficult to study. They are an integral part of life on Earth and yet, for the most part, they remain a hidden majority of living organisms dwelling in the depths of water bodies. Microbes are the processing factories of geological, chemical, and biological interactions on Earth.
- Photosynthesis: Marine microbes like phytoplankton and cyanobacteria are estimated to provide more than 70% of the oxygen we need to breathe. If not for these microbes converting the sun’s energy into chemical energy using the electrons and protons from the water, we wouldn’t even be alive today. The massive abundance of microbes in the sea results in the release of large amounts of carbon dioxide which gets absorbed by phytoplankton and other autotrophic organisms during the process of photosynthesis. Thank you, Microbes!
- Nutrient Cycling: Not every microbe can prepare its own food using photosynthesis or eat other organisms for energy. Some don’t even have a mouth to ingest food or have any microorganisms that are smaller than them to prey upon. What happens to such microbes? Bacteria are such organisms that play a unique role in the recycling of nutrients and transferring energy within the aquatic food web. Essentially, bacteria can be thought of as decomposers. They decompose dead animals or plants and other organic wastes that are created by all the living things. And as they decompose dead matter, they are also able to consume some part of it which is known as ‘Dissolved Organic Matter’ (D.O.M.). Not only does bacteria recycle the organic matter into nutrients that can be used by the plants, but they themselves become food for larger microscopic organisms like flagellates and ciliates. Thus these microorganisms become members of the food web in two ways – providing nutrients and becoming food themselves. Hence, the energy gets transferred up the food chain. Without the bacteria, this would not be possible and the cycling of matter would get disrupted. This phenomenon is also referred to as ‘microbial loop’ by various scientists and researchers in the field.
- Human Health Impacts: The world’s oceans are still used for disposal of human wastes in many parts of the world. While small amounts of sewage, industrial or human wastes can dissipate quickly, routine dumping of such wastes has caused harm to many ecosystems. At various sewage treatment plants, microscopic bacteria are cultured and then used to break down human wastes. But even though bacteria are mostly beneficial, human pathogens are known to develop disease-causing viruses that can prove fatal to humans. For example, Escherichia coli which can be found in coastal waters, if ingested can cause organ damage and other life-threatening circumstances.
We must realize the vital role microbes play for the sustenance of life on our planet and do our best to not come in their way of the natural processes they undergo for our benefit.