As if the ocean wasn’t scary enough, some of its dangerous inhabitants lurk unseen beneath the surface. And they’re not only limited to oceans but also rivers, ponds, and other bodies of water.

Micro-pests have a significant impact on other water creatures as well as humans, sometimes causing serious illnesses. Here’s how micro-pests are tracked and managed.

What are Micro-Pests?

Micro-pests are tiny organisms that negatively affect environments such as aquatic ecosystems. Here are some examples of micro-pests and how we can track them.

Plankton Pests: Microscopic Organisms Floating With the Current

Plankton are microscopic organisms that can’t swim but instead float with the current. They’re important for the health of the environment, but even plankton can be harmful in some cases.

Plankton are divided into two categories: phytoplankton and zooplankton.

Phytoplankton: Phytoplankton is also known as microalgae. Like plants, this microscopic marine algae contains chlorophyll and needs sunlight to live and grow. Most phytoplankton live near the water’s surface, where they get ample sunlight. It’s important in ponds and other aquatic ecosystems for several reasons, including that it’s a source of dissolved oxygen from photosynthesis and that it minimizes aquatic plant growth.

However, some phytoplankton species produce biotoxins that can accumulate in shellfish. These toxins may cause seafood poisoning in ocean waters. Furthermore, as the National Library of Medicine reports, they may cause skin, liver, hepatic, and gastrointestinal tumor promotion activity. Toxic algae are more common in coastal water than in freshwater.

Excess phytoplankton can cause:

• High afternoon pH
• Low nighttime dissolved oxygen concentrations
• Shallow thermal stratification of the water column in ponds

According to Global Seafood, “The simplest tool for assessing phytoplankton abundance is the Secchi disk, which is ‘read’ according to the depth at which it disappears from view.” It’s a proxy for phytoplankton levels rather than a direct measuring tool. Other methods, such as chlorophyll-a measurements, may be used for more precise assessments.

Waters with elevated inorganic nitrogen and phosphate concentrations usually contain a lot of phytoplankton. Waters that lack phytoplankton usually need more nutrients like inorganic nitrogen and phosphate.

On the other hand, waters with too much phytoplankton need fewer of these nutrients. Early detection is crucial. Algal blooms can also be managed with natural predators and competitors of phytoplankton, like types of zooplankton.

Zooplankton: Zooplankton are tiny animals living near the water’s surface that are classified by size and developmental stage. We classify them by stage using two categories: meroplankton and holoplankton. Meroplankton are larvae that change into worms, fish, insects, and so forth. On the other hand, holoplankton stay plankton their entire lives.

Holoplankton found in the ocean include arrow worms, diatoms, radiolarians, dinoflagellates, foraminifera, amphipods, krill, copepods, salps, comb jellies, and jellyfish, as well as some gastropod mollusk species like pteropods.  Holoplankton in freshwater include rotifers, daphnia, cyclops, waterbugs, diving beetles, and boatmen.

Some zooplankton are considered pests because some of their traits make them dangerous. For instance, while copepods like Cyclops aren’t pests per se, they can be hosts for parasites that infect fish or transmit diseases to humans. Therefore, we could consider them pests under certain conditions.

Typically, trained taxonomists use microscopes to measure zooplankton quantities and diversity. But other methods, like plankton nets, are available for estimating zooplankton abundance.

According to ScienceDirect, “Promising options for zooplankton control include physical methods such as filtration, hydrodynamic cavitation, shear, and bead mills; chemical methods such as increasing HRAP night-time CO2 concentration, promoting the lethal un-ionized ammonia toxicity, using biocides and the chitinase inhibitor chitosan; and biocontrol using competitor and predatory organisms.”

Parasites: Organisms That Feed on Other Organisms

We mentioned that some zooplankton are problematic because they carry parasites. It’s only logical that the next micro-pests are parasites themselves. Parasites live inside another organism called the host. They live off the host and steal its nutrients.

An example of a water parasite is parasitic protozoa. According to the National Library of Medicine, some protozoa cause human infections. Those include:

• Toxoplasma gondii
• Entamoeba histolytica
• Cyclospora cayetanensis
• Isospora belli
• Blastocystis hominins
• Balantidium coli
• Acanthamoeba spp.
• Sarcocystis spp.
• Naegleria spp.

Water samples can be analyzed for the presence of parasites. Parasites are usually managed through:

• Water treatments
• Education
• Good sanitary conditions

Unfortunately, the processes of treating drinking water are often unattainable in developing countries, which increases the risks of human infections.

Bacteria: The Threat Below the Surface

Dangerous and even deadly bacteria spread through the waters. For instance, as Scientific American reports, “Multiple species of rod-shaped Vibrio bacteria live in the world’s oceans, and their populations rise and fall based on many different variables, changing the likelihood of making people sick.”

The article goes on to say that the Vibrio bacteria causes about 80,000 illnesses and 100 deaths yearly in the U.S.A. alone. The World Health Organization reports that the Vibrio cholerae bacteria causes up to 142,000 yearly deaths worldwide.

Bacteria can be detected with various methods, like water sampling. Like parasites, bacteria in water is managed through:

• Water treatments
• Education
• Good sanitary conditions

How to Make Water Cleaner

While you may not have much to do with your local plankton population, you can still do a lot to keep local water clean. Remember these eco-friendly practices:

• Reduce pollution: Minimize your use of chemicals like fertilizers, pesticides, and fungicides.
• Dispose of waste properly: Make sure you dispose of all your waste to prevent it from contaminating water sources.
• Conserve water: Save as much water as possible. Don’t leave taps running or irrigate your lawn when unnecessary. Fix any leaks in your water system as soon as possible. Consider xeriscaping your landscape.
• Fix leaky faucets and fix gaps around pipes: These are two of the best ways to keep sewer roaches out of your drains. Sewer roaches, of course, can spread dysentery, diarrhea, and salmonella.

We can do much to be better stewards of our water resources in our homes and the oceans. If more of us consciously try to make a difference, the impact will be more than a drop in the ocean.

Judith Gallova is a freelance home and yard improvement writer. She explores plant care essentials using her skills and research to help you maintain a beautiful garden. In her free time, Judith likes to spend time with loved ones, stroll through nature, and study the Bible.