From Sea Grass Change to Meth-Addicted Trout: See How Pollution Affects the Wildlife 

Pollution can happen in many things. And as we know, human made pollution can harm the wildlife, land or water.  

Now, while noise pollution is not good for marine animals like whales to scallops, it’s apparently bad news for non-animals. A new study has shown that this pollution negatively affects one species of seagrass, a marine plant. 

To be specific, the marine plant is Neptune grass, which is unfortunately also a protected species native to the Mediterranean Sea. This species can get significant acoustic damage when they ‘listen’ to low-frequency artificial sounds for only two hours. 

The damage is apparent in the parts of the plant responsible for detecting gravity and storing energy. 

Michel André is a bioacoustician who led this research. He said he got the inspiration to do this research ten years ago after he and his colleagues found that cephalopods suffer massive acoustic trauma when exposed to low-frequency noise.  

André said, “This totally shifted our vision and our approach to noise pollution.” We should remember that until that point, researchers and many still focused on concerns for whales and dolphins.  

They use sound to mate, find food, communicate, and navigate, which was concerning at that time. Still is until now actually, but other marine creatures like corals and jellyfish that possess statocysts have the same potential risks from human-generated noise.  

Even though seagrasses don’t possess statocysts, they have similar sensory organ called an amyloplast. They’re gravity-sensing cells that help underwater plants push their roots down through seafloor sediments.  

The experiment on seagrass 

Because of the similar sensory organ to creatures with statocysts, scientists wanted to test the effects of noise on plants.  

In their latest experiment, André and his colleagues used a loudspeaker. They blasted a dynamic mix of artificial sounds with frequencies from 50 to 400 hertz to tanks of Neptune grass. The sound ranges from noises associated with human activity. 

After exposing the seagrass to this low-frequency mixed tape for two hours, the researchers used electron microscopes to examine the amyloplasts. They investigated the seagrass’ roots and rhizomes, which are underground stems that store energy as starch. 

What they found was that the acoustic damage was acute and worsened over the next five days. Moreover, starch levels inside the seagrass’ amyloplasts dropped dramatically and the symbiotic fungus in the roots didn’t do well either. 

Even though it may seem insignificant, since these are just plants, Neptune seagrass sequester lots of carbon dioxide out of the atmosphere by storing it as starch.  

As the time goes, seagrass meadows build up in layers locking carbon in several-meter-thick mats that can persist for thousands of years. 

This discovery, according to André, is just the beginning. “There is no reason to think that other plants should not suffer from the same trauma,” he said. 

 

Animal vision affected by light pollution 

Even though we know that insects seem to love light, it doesn’t mean that we gotta turn the lights on all the time. Artificial lighting can have more subtle consequences for species that rely on night vision for their behavior. 

That’s according to the findings of University of Exeter researchers. They’ve examined the impact 20 kinds of lighting on the vision of moths, and birds that eat them. 

The researchers found that elephant hawkmoth vision was enhanced by some types of lighting and disrupted by others. On the other hand, the vision of birds that hunt moths was improved by almost any lighting. 

 

elephant hawkmoth by gailhampshire Wikimedia Commons

 

Lighting during night time has increased rapidly worldwide and it has changed quite significantly in the last 20 years. We’ve seen a lot more modern lights like LEDs than the ole amber streetlights.  

According to Dr. Jolyon Troscianko of the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall, “Modern broad-spectrum lighting allows humans to see colour more easily at night. However, it is difficult to know how these modern light sources affect the vision of other animals.” 

Even though hawkmoth eyes are sensitive to blue, green, and ultraviolet to find flowers like bees, they do it at incredibly low light levels. They can do it under starlight, in fact. 

“Moths are also vitally important pollinators—accounting for a similar proportion of pollination as bees—so we urgently need to investigate how lighting affects them,” Dr. Troscianko continued. 

The potentially harmful benign lights 

What’s more, the study also finds that phosphor converted amber LED lighting has unpredictable consequences for insect vision. These lights often suggested to be less harmful to nocturnal insects. But depending on distance from the light source and the color of viewed objects, the impacts are still unclear. 

White lights with greater blue component can show more natural color vision in moths. However, other species are not compatible, so to speak, with these light sources.  

Therefore, so far there’s no clear solution to this problem even though we have to act quickly. Moth numbers are declining across Europe, as are with other nocturnal species. 

So far, the researchers’ suggestion is to limit the amount and intensity of light wherever possible. 

 

Trout species which has become meth addicts 

Disposing trash or chemicals in waterways, either accidentally or on purpose, can affect water animals in ways that we don’t expect to happen. After all, when trash or chemicals enter the waters, they see them as food. 

In a new study, researchers tested the effect of methamphetamine on brown trout (Salmo trutta). Why meth, did you ask? Well, it’s apparently a common drug found in wastewater in both the USA and Europe. And yes. Long story short, meth has the fish hooked. 

Now, meth use has apparently skyrocketed during the pandemic. And because this drug isn’t completely absorbed when consumed, they exit the body via excrement.  

Up until now, however, wastewater treatment plants can’t exactly remove this kind of contaminant. So, the sewage water is loaded with meth and it goes back to the environment without us being able to control its level. 

Study author Pavel Horky from Czech University of Life Sciences Prague said, “Where methamphetamine users are, there is also methamphetamine pollution of freshwaters.” 

How did the researchers find out? 

The research team studied the effects of the drug on this species by lab experiment. They tried to replicate meth-polluted wastewater and placed 60 trout in that water tank.  

Researchers made the tank match the levels of discharge from wastewater treatment plants in Czechia and Slovakia. 

 

Brown trout or Salmo trutta fario by Gilles San Martin Wikimedia Commons

 

Then, the researchers forced the trout to quit meth cold turkey after two months of living in meth-loaded environment. They found that these trout moved around less than the non-addicted trout, which is a sign of withdrawal. 

Horky’s team also found traces of meth in the trout’s brains up to ten days after the exposure. 

After this, researchers gave both addicted and clean trout the option to enter either a stream filled with meth or another without. And it’s no surprise; meth-exposed trout preferred to return to the drug-filled stream, compared to the clean trout. 

So, the researchers took this phenomenon as a sign of addiction. 

What will be the effect of this? Well, meth consumption can lead to detrimental effect for this species in the wild. They can have difficulties finding food, change their usual migration patterns, can’t find mates, and be vulnerable to predators. 

Moreover, addicted trout may also seek out sources of the drug and make them flock around wastewater treatment areas. That’ll disrupt distribution in their natural habitats and eventually create chaos across the food web. 

There’s still no clear solution to solve this issue, but at least we know it today.  

 

Sources

https://www.smithsonianmag.com/science-nature/seagrass-harmed-noise-pollution-180978290/ 

https://www.sciencedaily.com/releases/2021/07/210706102041.htm 

https://www.smithsonianmag.com/smart-news/meth-pollution-waterways-turning-trout-addicts-180978133/ 

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