A Simple Guide About Plankton and Their Importance to Our Future
You know that distinctively awesome smell that gets you all excited as you get closer to the sea? It’s produced by bacteria feeding on decaying plankton and marine plants.
While googling about what caused the ocean scent, I learnt that plankton make more than half of our oxygen. How incredible is that? I got curious and read up on these tiny organisms. They’re fascinating!
There are two main types of plankton: phytoplankton and zooplankton. Phytoplankton: Plant plankton or photosynthetic organisms that turn sunlight and carbon dioxide to into energy.
Zooplankton: Animal plankton feed on phytoplankton and are in turn, eaten by other marine animals, like the magnificent right whale.
Plankton has to be one of the most underrated organisms in the world. They’re so important to us, but most of us know little about them.
Why plankton are important
Phytoplankton produces oxygen and removes carbon dioxide from the environment: Phytoplankton and algal plankton produce 50% of the world’s oxygen. However, oxygen production isn’t the most important thing they do.
When phytoplankton photosynthesizes, they remove carbon dioxide from and release oxygen into the environment. They’re natural carbon sinks. When they die, they sink and transfer the carbon incorporated in them to the bottom of the ocean, trapping them for thousands of years.
Plankton forms the base of the marine ecosystem: Phytoplankton and algae make up the main producers* of the marine ecosystem. Phytoplankton feed zooplankton, which in turn, feeds small marine creatures and huge ones like the whales. They’re the basis of life in the ocean, and directly influence the healthiness of a marine food web.
* Producers are organisms that make their own food and forms the base of ecosystems. In a healthy food web, the base contains the biggest number of organisms, and the number decreases higher up the food web.
Plankton influence cloud formation: When stressed by UV light, plankton produces a chemical called DMSP, which gets broken down by bacteria into DMS. DMS is then released into the air in the form of tiny dust-like particles, promoting cloud formation.
The clouds shield the ocean from the harsh UV light, keeps it cooler and protect marine plants.
How we’re affecting plankton
Global warming
In nature, carbon dioxide are produced when animals breath and things decompose, or when plants and trees respire at night. In the day, photosynthetic organisms take in carbon dioxide and turn it into sugar for energy. It’s a beautiful and balanced cycle.
However, there has been a rapid increase of carbon dioxide production from the burning of fossil fuel and deforestation. We’re producing carbon dioxide faster than it can be removed from the atmosphere – causing an imbalance.
The excess carbon dioxide in the environment traps infra red radiation, causing earth and oceans to warm. Some of these carbon dioxide dissolves into the ocean, causing the ocean to acidify.
Scientists believe that the rise in sea temperatures has been causing the decrease of phytoplankton by 40% since 1950.
Research has also shown that cooler nutrient rich water from lower parts of the ocean cannot cycle to the higher levels where plankton reside, causing phytoplankton to lack material they need to convert carbon dioxide and sunlight into energy.
Plastic pollution
Researchers have found evidence that plankton are mistaking micro plastic for food, affecting their ability to survive and reproduce.
Plankton ingesting plastic causes bioaccumulation of plastic and toxins in the entire food chain. More on that later.
Nutrient Pollution
When fertilizers used at the farms run off into the ocean, they affect the diversity and balance of plankton in the ocean. Nitrogen and phosphorus from fertilizers and wastewater cause the population of certain phytoplankton to spike. This is known as algal bloom.
The sudden increase of algae and phytoplankton in the sea prevents oxygen and sunlight to reach the organisms beneath it. Since oxygen cannot reach the organisms and marine plants cannot photosynthesize and create oxygen, dead zones form underneath these algal blooms.
When the phytoplankton die, they decompose and use up the oxygen in the water, killing most organisms in the water and aggravating the problem.
Effects of plankton loss
Reduced oxygen in the ocean
As the ocean warms and the amount of plankton decreases, there’re lesser phytoplankton to produce oxygen.
At the same time, our continual release of carbon dioxide meant that more carbon dioxide will be absorbed into the ocean, causing ocean acidification.
With lesser oxygen and too much carbon dioxide, the ocean will suffocate.
Worsening global warming
When phytoplankton photosynthesize, they take in heat-trapping carbon dioxide and release oxygen into the ocean and the environment. It’s thanks to their absorption of carbon dioxide that the earth is not warmer!
As mentioned before, phytoplankton are natural carbon sinks that helps to lock carbon at the bottom of the ocean when they die.
With their numbers reducing, more carbon dioxide will remain in the atmosphere, accelerating global warming.
Shortage of food
The reduction of plankton population will tip the entire marine ecosystem off balance. Small fishes and squids that feed on plankton would find themselves with a shortage of food. This reduces their numbers, which in turn reduces the food source for larger animals feeding on them, causing shortages of food all the way up the food chain.
The entire marine food chain will shrink. The numbers of dolphins, sharks, and whales will decrease. And its effects doesn’t stop in the ocean. Sea birds, penguins, seals and polar bears would find themselves with a lack of food too.
Ultimately, it’ll affect our supply of seafood. Communities, trades and economies with high dependence on the seafood supply will take the worst hits.
Bioaccumulation of plastic and toxins
Aside from plankton loss, bioaccumulation is also an important issue to look at.
Microplastic tends to contain a lot of chemical contaminant – this is often a result of the production process or the recycling process. Hydrophobic contaminants in the ocean also tend to attach itself to microplastic.
When small fishes eat plankton that consumed contaminated microplastic, they use the energy and nutrients from the plankton and retain contaminants in their tissues.
When bigger fishes eat small fishes, the same process happens – they use the energy and nutrients from the small fishes and the contaminants accumulate in their tissues. This phenomenon is bioaccumulation.
The higher up on the food chain, the more plastic and toxin bioaccumulate in the animals, the more unhealthy its populations would become.
Ultimately, the toxins end up on our plates.
What we can do for them
Plankton may be tiny, but they’re definitely significant. They play a critical role in the survival of humans and many species of marine animals in the ocean.
Without plankton, our food and oxygen supply will dwindle; marine animals and animals feeding on them will starve; and global warming will be accelerated. Yet, I never gave them much thought until the past couple of months.
Here are some things we can do to help protect plankton.
- Reduce your plastic use. Stop using products that contain microbeads, glitter and stop buying clothes made with synthetic fiber. Marine creatures often mistake microfiber from clothes for food.
- Reduce energy consumption and use public transportation to reduce the need to burn fossil fuels.
- Be mindful of how you use fertilizers to prevent nutrient run off into the sea to prevent algal bloom.
- Eat lesser meat – meat has a huge carbon footprint and is a huge contributor to global warming and deforestation.
- Support causes to protect habitats on land and in oceans – this preserves parts of earth’s lungs and helps to slow down global warming.
- Spread awareness about what phytoplankton do and what we’re doing to them. Understanding the problems helps us to handle them better!
If you were like me and never gave these tiny organisms much thought, I hope you’ve found the post informative. The more we know how our actions are impacting our environment, the better we’ll be at fighting climate crisis!
I’ve tried my best to put together what I’ve learnt about phytoplankton, and not being a marine biologist, my understanding or explanation may not be perfect. If you spot any error in the post, kindly let me know.
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