Marine Microplastics and Zooplankton

How marine microplastics are disrupting the planet’s most abundant animals, zooplankton, and the systems they support.

What does every landscape on the planet have in common? From the highest peaks to the uninhabitable deserts to the deepest depths of the ocean, and everywhere in between, plastic pollution is present.

By now you know we at Bee Wild Outside are consumed by plastic pollution. Our recent blog, Plastic Pollution, and Coral Reefs introduced zooplankton as an unintentional carrier of microplastics into the marine reef ecosystem. In this blog, we explore how microplastic vis-a-vis zooplankton upsets the homeostasis of our oceans.

What is Zooplankton?

Zooplankton are the most abundant animals on the planet. Zooplankton play a vital role in the marine food system and in regulating the Earth’s climate; aquatic superheroes. Zooplankton are tiny animals like krill and copepods, and immature stages of larger animals like baby crabs and fish. Zooplankton feed on microscopic plant-like organisms called phytoplankton, which get their energy from the sun.

Microplastics

Microplastics (<5mm in size) are found everywhere in our oceans and include particles and fibers of various shapes, sizes, colors, and materials. Microplastics come from two main sources. The first are nurdles or mermaid tears. These small plastic pellets are the raw materials used to manufacture plastic goods. The second are derived from the breakdown of larger plastic litter through exposure to sun and erosion, or they are released into wastewater when we wash nylon or polyester clothing. Researchers believe there could be as many as 125 trillion pieces of microplastic floating in the oceans; this number is growing.

The story of microplastics gets worse. As microplastics move through natural systems like the ocean they encounter environmental pollutants that attach to their surface. Microplastics act as a kind of magnet for the pollutants, concentrating them on their surfaces. When non-organic plastic and the organic pollutant converge, the toxicity of the pollutant is compounded. This toxicity threatens the marine environment and ultimately human health.

Microplastic and Zooplankton

Plankton are aquatic organisms that are unable to swim effectively against currents. There are two main types of plankton, phytoplankton which are plants and zooplankton which are animals. Both phytoplankton and zooplankton drift or are carried along by currents in the ocean. Zooplankton feed on phytoplankton and then become food for animals up the food chain.

Zooplankton are filter feeders. Filter feeders lack complex digestive systems and feed through filtering large quantities of water; filter feeders come in all shapes and sizes, from tiny zooplankton to the largest animal on the planet, the blue whale. The filter feeder’s natural diet is phytoplankton. Inevitably they ingest microplastics of similar size to phytoplankton. Microplastics impair natural digestion, for zooplankton, this means they don’t get sufficient nutrients which inhibits their development and reproduction.

This fact by itself is troubling news; recall that zooplankton are integral to the larger marine food system and climate regulation.

Zooplankton and the Marine Food Web

Disruption of both phytoplankton and zooplankton impedes the larger marine food chain. Microplastics then affect fish, sea birds, jellyfish, coral, marine mammals, and apex predators such as killer whales, great white sharks and leopard seals.

Fish that ingest zooplankton at high levels and we’ve seen that most fish do are ingesting dangerous toxins that build up in their systems (think mercury in tuna, PCBs in freshwater fish). These toxins negatively impact growth, health and reproduction. The ingestion of toxic chemicals and microplastics by predators means that eventually these plastics and chemicals that we have dumped into our environment will come full circle by making their way to our dinner plates!

Zooplankton and Carbon Cycling

Aside from being an integral part of the marine food chain zooplankton also play a critical role in what’s know as carbon cycling through photosynthesis. When zooplankton eat carbon rich phytoplankton, their excrement naturally sinks to the bottom ocean floor. When the excrement contains microplastics it floats and rereleases carbon back into the atmosphere as CO2.

What Can We Do?

The story of zooplankton is a tragic reminder of how interconnected all life on earth is and illustrates that microplastics persist; they don’t degrade, they simply cycle through each new system impeding the natural food train.

Almost half the plastic made is single-use plastic, designed to be used once and thrown away. Together, we individuals can make a huge difference. With over 8 Billion people on the planet, imagine every person reducing single-use plastic by one item per day; that’s 56 Billion fewer pieces of plastic per week entering the environment.

Small Actions Create Big Impact

Five simple ways to achieve this:

Use a refillable water bottle.
Refuse single-use plastic water bottles from hotels, stores, and restaurants. Request instead that they create water refill stations.
Use a reusable coffee cup. Some shops extend discounts for using your own cup.
Don’t let trash reach our waterways. When you see trash on the street, trail, or beach, pick it up!
Inspire change by sharing what you learn with family and friends.

How We at Bee Wild Outside are Tackling This Issue

Bee Wild Outside is blazing the path for sustainable sun care by protecting you without polluting the earth.

Our clean sunscreen is refillable and recyclable:

Non-toxic, mineral formula.
Aluminum refills are 100% recyclable.
Forever reusable dispenser is Ocean Waste Plastic.

We are removing nasty chemicals and single-use plastic from your daily sun care routine.

Join our journey to remove single-use plastic from sun care.

Sign up for our monthly newsletter or drop us an email to share ideas and questions about our sunscreen or to share your story about going plastic-free!

Sources:

Nature Communications: Zooplankton grazing of microplastic can accelerate global loss of ocean oxygen

Slate: When Plankton Gobble Plastic

oceanbites: Plankton are eating plastic!

Science Direct: Bioavailability and effects of microplastics on marine zooplankton: A review

NOAA: Aquatic food webs

Science Daily: Microplastics increase the toxicity of organic pollutants in the environment by a factor of 10, study finds