Warming Seas and Microplastics Are Harming Sardines—And Us

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Infographic showing how feeding behavior and temperature affect plastic fibre ingestion in European sardines (Sardina pilchardus). Sardines that use filter-feeding ingest more plastic fibres, expel them faster, and have a lower condition index compared to particulate-feeding sardines. Warmer temperatures (19°C) increase plastic fibre ingestion and speed up intestinal transit time.


Feeding behavior and warming seas influence plastic fibre ingestion in sardines. Sardines that filter-feed ingest significantly more plastic fibres than those that eat larger particles (particulate-feeding). Warmer water temperatures (19°C) lead to faster digestion but also more plastic consumption. Filter-feeding sardines show lower health scores, highlighting the combined stress of microplastic pollution and climate change. (Source: Rodriguez-Romeu et al., 2024)

Sardines may be small, but they play a big role in the ocean—and on our dinner plates. These little fish are a key food source for larger marine animals like dolphins and tuna, and millions of people around the world eat them, too. They’re also packed with nutrients and are considered one of the most sustainable seafood choices out there.

But sardines are in trouble. In the Mediterranean Sea, their population has dropped sharply in recent decades. And scientists are discovering that two major forces—warming ocean temperatures and plastic pollution—are teaming up to make life even harder for these essential fish.

What’s harming sardines may be a warning sign for us all.

The Hidden Threat: Plastic Fibres in the Ocean

Microplastics are tiny pieces of plastic that break down from larger items like bottles, bags, and packaging. But not all microplastics are the same. A specific type called plastic fibres is even more common in the ocean—and more likely to be eaten by fish.

Plastic fibres are tiny thread-like pieces that come from clothing, fishing gear, and other waste. They’re too small to see with the naked eye but can float in the water, where fish easily mistake them for food. In fact, up to 91% of microplastics in ocean water are fibres, making them the most common type of plastic pollution in the sea.

The Experiment: What Scientists Found

To better understand how sardines interact with plastic fibres, scientists designed a unique experiment. They took wild sardines and placed them in tanks that mimicked ocean conditions. The tanks contained a realistic amount of plastic fibres—five fibres per liter of water, similar to what’s found in polluted areas of the sea.

They fed the sardines in two different ways:

  • Particulate-feeding: Fish were given large food pellets, which they eat one by one.

  • Filter-feeding: Fish were given tiny particles, similar to how they naturally eat plankton by filtering water through their gills.

The scientists also tested two water temperatures:

  • 16°C, which reflects current Mediterranean conditions.

  • 19°C, which represents a possible future scenario as oceans warm due to climate change.

Startling Results: What Happened to the Sardines

The results were clear—and concerning.

Sardines that fed by filter-feeding accidentally ate about eight times more plastic fibres than those eating larger particles. On average:

  • Filter-feeders ingested 4.95 fibres per fish

  • Particulate-feeders ingested only 0.6 fibres per fish

Temperature also made a difference. At warmer temperatures (19°C):

  • Sardines expelled plastic fibres faster, likely due to faster digestion.

  • But they also ingested more plastic, probably because their metabolism increased and they needed more food.

Another discovery: Plastic fibres stayed in the sardines’ digestive system longer than real food. Half the food was gone in about 12–14 hours, but it took 23–25 hours to get rid of just half the plastic fibres.

The Health Impact on Sardines

Over the course of the experiment, filter-feeding sardines didn’t just eat more plastic—they also got weaker.

  • They lost more weight and had lower body condition scores compared to those eating larger particles.

  • Their stomachs were less full, which suggests they ate less food overall and didn’t get enough energy.

Interestingly, the plastic alone wasn’t what made them unhealthy. Instead, it was the combination of filter-feeding and warmer water that seemed to hurt them most. Warmer oceans can lead to smaller plankton, which makes filter-feeding more common—and that leads to more plastic being ingested.

Why This Matters for Climate and Human Health

The health of sardines isn’t just a fish problem—it’s an ocean problem and a human problem.

Here’s why this matters:

  • Warming oceans = smaller plankton

  • Smaller plankton = more filter-feeding by fish

  • More filter-feeding = more plastic consumed

If sardine populations continue to shrink:

  • Predators like tuna, dolphins, and seabirds could lose a key food source.

  • People who depend on sardines for protein or income may struggle.

  • Ocean ecosystems could become unbalanced.

These changes don’t happen in isolation. Climate change and plastic pollution often work together, creating stress that marine life—and people—may not be able to overcome.

What Can We Do?

The good news is that small changes on land can protect life in the sea. Here are a few steps anyone can take:

  • Choose clothes made from natural fibers (like cotton or wool). Washing synthetic clothes sheds plastic fibres into the water.

  • Reduce plastic packaging by using reusable bags, bottles, and containers.

  • Support ocean cleanup efforts and organizations that study microplastics.

  • Advocate for climate action, including clean energy and reduced carbon emissions, to help slow ocean warming.

  • Hold your local, state, and national elected officials accountable for taking climate action and protecting our water, air, and health.

A Call to Protect What Connects Us All

Sardines may not get much attention, but they’re part of a delicate chain that connects us all. When small creatures suffer, the effects can ripple through the food web—and onto our plates.

The choices we make on land ripple into the sea—and into our future.

By staying informed, reducing plastic use, and supporting climate action, we can help protect the ocean, our food systems, and the health of generations to come.

Source: Rodriguez-Romeu, O., Constenla, M., Soler-Membrives, A., Dutto, G., Saraux, C., & Schull, Q. (2024). Sardines in hot water: Unravelling plastic fibre ingestion and feeding behaviour effects. Environmental Pollution, 363, 125035. https://linkinghub.elsevier.com/retrieve/pii/S0269749124017500

Microplastics in Our Brains

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A minimalist illustration of a human head in profile with a vintage-style anatomical drawing of a brain superimposed inside.
A conceptual illustration depicting human cognition, featuring a vintage anatomical drawing of a brain within a simple silhouette of a head.

What You Need to Know and How to Reduce Your Exposure

Did you know that tiny plastic particles—called microplastics—are in our food, water, and even the air we breathe? Every day, we are unknowingly consuming and inhaling microplastics. Scientists have now discovered something even more concerning: microplastics are making their way into human brains, and their levels are increasing.

This raises an important question: What does this mean for our health, and what can we do about it? While we may not be able to eliminate microplastics entirely, there are simple steps we can take to reduce our exposure and protect our health. In this article, we’ll break down what microplastics are, how they enter our bodies, the potential health risks, and practical ways to reduce our exposure.

What Are Microplastics?

Microplastics are tiny plastic particles, smaller than 5mm, that come from broken-down plastic waste, synthetic clothing, industrial processes, and food packaging. Because plastic never fully biodegrades, these particles remain in the environment indefinitely, breaking down into even smaller pieces over time.

Common Sources of Microplastics

Microplastics are found in everyday items, including:

  • Bottled water: Contains significantly more microplastics than tap water.

  • Seafood: Marine animals ingest microplastics from polluted oceans.

  • Processed foods: Particularly those packaged in plastic.

  • Tea bags: Some brands use plastic-based tea bags that release billions of plastic particles into hot water.

  • Air: Microplastics are floating around in household dust and city pollution.

Since we eat, drink, and breathe microplastics daily, it’s important to understand how they enter our bodies and what harm they may cause.

How Do Microplastics Get into the Human Body?

Microplastics make their way into our bodies through three primary routes:

Eating and Drinking

  • Bottled water drinkers ingest up to 90,000 microplastic particles per year, compared to 4,000 for tap water drinkers (Cox et al., 2019).

  • Seafood, processed foods, and canned goods can contain microplastics due to contamination during production and packaging.

  • Heating food in plastic containers releases billions of plastic particles into the food.

Breathing

Airborne microplastics are present in the air we breathe at home, in offices, and outdoors, particularly in urban areas. Additionally, synthetic clothing sheds plastic fibers into the air when it is washed or worn, further contributing to the inhalation of these particles.

Household Exposure

Cooking and storing food in plastic can cause microplastics to leach into the food we eat. Similarly, plastic tea bags and coffee pods release billions of tiny plastic particles into hot liquids, increasing overall exposure.

Because these tiny particles are everywhere, scientists are now studying how they affect our health—especially our brains.

Are Microplastics Harmful to Our Health?

While research is still ongoing, several studies have raised serious concerns about microplastics in the human body. Here’s what scientists have found so far:

Microplastics in the Brain

A recent study found microplastics in human brain tissue, with levels 3–5 times higher in people with dementia (Nihart et al., 2025). Scientists are unsure whether dementia weakens the brain’s defense, allowing more plastic in, or if microplastics contribute to cognitive decline.

Heart Disease Risk

A study found that people with plastic particles in their arteries had a higher risk of heart attacks and strokes (Marfella et al., 2024).

Gut Health Concerns

People with inflammatory bowel disease (IBD) had 1.5 times more microplastics in their stool compared to healthy individuals (Yan et al., 2022). Microplastics may disrupt gut bacteria and contribute to inflammation.

Other Potential Effects

Scientists suspect microplastics may also contribute to:

  • Hormone disruption: some plastics contain chemicals that interfere with the endocrine system.

  • Lung irritation: from inhaling airborne microplastics.

  • Long-term health risks: still being studied.

Since avoiding microplastics completely is impossible, the next best step is reducing exposure where we can.

Easy Ways to Reduce Microplastic Exposure

While plastic is everywhere, simple daily changes can significantly lower the amount of microplastics we ingest and inhale.

  • Switch to Tap Water: Drinking tap water instead of bottled water can reduce microplastic intake by over 90%. Use a water filter if concerned about contaminants.

  • Avoid Heating Food in Plastic: Use glass or stainless steel containers instead of plastic. Never microwave food in plastic containers.

  • Choose Fresh or Frozen Foods Over Canned: Canned foods can release chemicals like BPA, which is linked to hormone disruption. Opt for fresh, frozen, or glass-packaged alternatives.

  • Use Cloth or Metal Tea Strainers: Avoid plastic tea bags—opt for loose-leaf tea with a stainless steel infuser.

  • Improve Air Quality: Use a HEPA air filter at home to remove airborne microplastics. Vacuum regularly to reduce plastic dust indoors.

These small changes can make a big difference in reducing everyday exposure.

Can Microplastics Be Removed from the Body?

Right now, scientists don’t know if microplastics can be fully removed from the human body, but some early research suggests:

  • Sweating may help: Some studies suggest that sweating (through exercise or sauna use) can help excrete plastic-related chemicals like BPA.

  • Healthy lifestyle choices: Staying hydrated, eating fiber-rich foods, and regular exercise may help the body naturally eliminate toxins.

  • Long-term exposure reduction: The best strategy is reducing intake in the first place.

More research is needed, but reducing microplastic exposure now is the safest approach.

Small Changes Make a Big Difference

Microplastics are everywhere, and while we can’t avoid them completely, we can take practical steps to limit exposure and protect our health. By making the choices we suggested above, you can help protect your health while also reducing plastic pollution in the environment.

It’s crucial to hold local, state, and national elected officials accountable for policies that protect your health and the well-being of your loved ones. Be mindful of who you vote for, and once they are in office, advocate for strong regulations that reduce plastic pollution and safeguard public health. Your voice matters—demand action.

Sources: Nihart et al., 2025 – Study on microplastics in the human brain (Nature Medicine). Marfella et al., 2024 – Microplastics and heart disease (New England Journal of Medicine). Cox et al., 2019 – Microplastic consumption (Environmental Science & Technology).

How Climate Change is Changing Our Food

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A pile of dried corn cobs, some with missing kernels.
Climate change is affecting crop yields—this image of dried corn cobs. Farmers face crop challenges with unpredictable weather patterns and environmental stress. Photo by Livier Garcia on Pexels.

What You Need to Know

Have you ever noticed that certain fruits or vegetables seem harder to find at the grocery store—or that prices for some foods have gone up significantly? If so, you’re not alone. Climate change is reshaping the way we grow food, affecting where crops can thrive and making some foods more difficult to produce.

As global temperatures rise, extreme weather events become more common, and rainfall patterns shift, farmers worldwide are facing new challenges. Some crops may no longer be able to grow in areas where they have been farmed for generations. Others may start appearing in places where they were once impossible to grow.

Below, we’ll explore how climate change is impacting food production, what it means for global food diversity, and what steps we can take to ensure a stable food supply for the future.

Why Climate Matters for Our Food

Every plant has specific needs—some require warmth, others need cooler temperatures, and all depend on the right amount of water. Imagine a banana tree—it flourishes in warm, humid regions. Now think about wheat, which grows best in cooler, drier climates. These differences explain why certain foods are grown in specific parts of the world.

But as global temperatures rise, these conditions are changing. Some places are becoming too hot or too dry for traditional crops, while others are experiencing floods or unexpected frosts. These shifts are forcing farmers to rethink what they plant and where they plant it.

  • More heat: Many crops, like rice and corn, have an upper temperature limit. Once it gets too hot, they stop growing.

  • Unpredictable rainfall: Some areas are getting too much rain, while others face droughts, making it harder to maintain stable harvests.

  • Soil changes: Rising temperatures and irregular rainfall can lead to soil degradation, making it harder to grow food in certain areas.

In short, climate change is making it more difficult to maintain the world’s current food production system.

The Problem – Crops Are Losing Their Homes

Scientists estimate that by 2100, up to 30% of global food crops could be growing in areas that no longer support them. The impact will be especially severe in low-latitude regions, which include parts of Africa, South Asia, and Latin America.

Take rice, for example—a staple food for billions of people. If global temperatures rise by just 2°C (3.6°F), 17% of current rice-growing areas may no longer be suitable for production. That means farmers in these regions could struggle to produce enough food, leading to higher prices and potential food shortages.

This problem isn’t just about one crop. Other key foods like coconuts, yams, cowpeas, and pigeon peas could also see 50% or more of their global production become unsustainable under 3°C warming.

For many farmers, this means tough decisions—either adapt to the new climate, switch to different crops, or move elsewhere. But for people in these regions who rely on farming for food and income, these choices are not easy.

Some Places Will Gain, Others Will Lose

While some regions are struggling, others may actually benefit from climate change—at least in the short term.

  • North America and Europe could see an increase in food crop diversity as warming temperatures make it possible to grow foods that previously required warmer climates.

  • For example, Canada and northern parts of the U.S. may become suitable for crops like peaches, figs, and even citrus fruits.

  • Parts of Africa and South Asia may lose traditional crops like maize and coffee as conditions become too hot or dry.

But this shift isn’t as simple as it sounds. Just because a crop can grow in a new location doesn’t mean farmers are immediately ready to produce it. They need the right equipment, knowledge, and infrastructure to make the transition successful.

Additionally, pests and diseases that once affected crops in warmer climates may start appearing in new areas, making farming even more unpredictable.

Why Losing Crop Diversity is a Big Deal

A diverse food system is a strong food system. When farmers grow a variety of crops, it helps:

  • Protect against crop failures: If one crop struggles due to drought or disease, others can still provide food and income.

  • Support a stable food supply: Different crops provide different nutrients, ensuring balanced diets for communities.

  • Strengthen ecosystems: Crop diversity can improve soil health, reduce pest outbreaks, and increase resilience to extreme weather.

Climate change is reducing crop diversity, especially in low-latitude regions. When fewer crops can grow in an area, food supplies become more vulnerable to disease, pests, and climate disasters.

For example, if a region depends heavily on one type of grain and that grain fails due to extreme heat, food prices can skyrocket, leaving many people without affordable options. This is why protecting crop diversity is essential for food security.

What Can Be Done?

While the challenges are real, there are ways to adapt and protect our food supply. Here’s how different groups can take action:

Farmers can adapt by:

  • Growing heat-resistant and drought-tolerant crops.

  • Using smarter irrigation systems to conserve water.

  • Practicing crop rotation to keep soil healthy and improve resilience.

Scientists are helping by:

  • Developing new crop varieties that can handle extreme weather.

  • Improving soil management techniques to keep farmland productive.

  • Researching alternative farming methods like vertical and hydroponic farming.

Governments and communities can support by:

  • Creating policies that support sustainable farming and innovation.

  • Investing in research and education for farmers.

  • Helping farmers transition to new crops when necessary.

Consumers can make a difference by:

  • Supporting local farmers: Buying locally grown food helps reduce the carbon footprint.

  • Eating seasonal foods: This reduces the demand for crops that require excessive resources to grow in the wrong climate.

  • Reducing food waste: Less waste means less pressure on global food production.

Every action, big or small, contributes to a more sustainable food future.

The Future of Food is in Our Hands

Climate change is already reshaping our food system. Some regions are struggling to maintain traditional crops, while others are seeing new opportunities. But without careful planning, food shortages, rising prices, and loss of diversity could threaten global food security.

The good news? There are solutions. Farmers, scientists, policymakers, and consumers all have a role to play in ensuring a resilient and diverse food supply for future generations.

So next time you’re at the grocery store, take a moment to think about where your food comes from. What if your favorite fruits and vegetables disappeared? What steps can you take today to support a more sustainable food future?

The choices we make now will shape the food we eat tomorrow.

Source: Heikonen, S., Heino, M., Jalava, M., Siebert, S., Viviroli, D., & Kummu, M. (2025). Climate change threatens crop diversity at low latitudes. Nature Food. https://www.nature.com/articles/s43016-025-01135-w?error=cookies_not_supported&code=4791b26a-7950-40df-9a19-33dc3e5ebeff