Phuket, with its beautiful beaches and crystal-clear waters, is a popular destination for both locals and tourists alike. However, if you’ve ever gone for a swim after a heavy rain, you may have noticed something strange: itchy skin. This uncomfortable sensation can be caused by several factors, but one of the most common culprits is plankton—microscopic marine organisms that flourish in the water after rain. So, why does this happen, and how can we prevent it?
Understanding the Role of Plankton in the Sea
Plankton are tiny organisms that live in both freshwater and saltwater. They play a vital role in the marine ecosystem, serving as food for a variety of marine creatures, from tiny fish to large whales. However, some types of plankton, especially dinoflagellates, can release toxins or irritate the skin when they come into contact with humans.
These plankton are particularly abundant in tropical regions like Phuket, where warm water temperatures and nutrient-rich conditions create the perfect environment for their growth.
Why Does It Happen After It Rains?
- Rainwater and Nutrient Runoff
- During heavy rainfall, nutrients such as nitrogen and phosphorus are washed off the land and into the sea. These nutrients, commonly found in fertilizers and organic matter, provide a food source for plankton, especially dinoflagellates.
- This influx of nutrients promotes plankton blooms, which are sudden increases in plankton populations. As these plankton multiply, they become more concentrated in the water, making it more likely that swimmers will come into contact with them.
- Warm Water Temperature
- Phuket’s tropical waters are naturally warm, providing an ideal environment for plankton to thrive year-round. During the rainy season, the water temperature remains high, which further encourages plankton growth.
- Turbidity and Water Clarity
- Rain can stir up sediment in the water, making it cloudy and reducing water clarity. This can increase the concentration of plankton near the surface of the water, putting swimmers in direct contact with them.
What Causes the Itching?
The itchiness and irritation you feel after swimming in the sea are mainly due to the presence of plankton, specifically dinoflagellates or other marine stingers. When you swim in water with a high concentration of plankton, they can release toxins or directly irritate your skin.
In some cases, small marine animals such as jellyfish larvae (commonly referred to as sea lice) may be present in the water. These tiny creatures can cause similar reactions, leading to itchy skin, redness, and even rashes. The stingers or toxins from these marine organisms can cause mild to moderate skin irritation, often accompanied by a burning sensation.
Symptoms of Skin Irritation After Swimming:
- Itchy skin: The most common symptom is intense itching, which can occur shortly after swimming in the sea.
- Redness and rash: You may notice red, blotchy patches on your skin, sometimes with raised bumps or welts.
- Burning or stinging sensation: Some people may feel a burning or stinging sensation immediately after exposure to the water.
- Hives or blisters: In more severe cases, the skin may develop raised areas (hives) or even blisters in response to the irritation.
How to Prevent Itching After Swimming in the Sea
While it’s not always possible to avoid the presence of plankton or other marine irritants, there are steps you can take to minimize the risk of itching and irritation:
- Avoid Swimming After Heavy Rain: If the rain has been particularly heavy, it’s best to avoid swimming in the sea for at least a few hours. The heavy runoff could lead to higher concentrations of plankton and other irritants in the water.
- Shower Immediately After Swimming: Always rinse off with fresh water as soon as you exit the sea. This will help remove any plankton or toxins from your skin and minimize the risk of irritation.
- Wear Protective Swimwear: If you’re concerned about coming into contact with plankton or other marine irritants, wearing a rash guard or a full-body swimsuit can help protect your skin from exposure.
- Use Anti-itch Creams or Lotions: After swimming, apply a soothing lotion or cream that contains aloe vera, calamine, or hydrocortisone to help calm irritated skin. These ingredients help reduce inflammation and itching.
- Stay Hydrated: Plankton-induced irritation can worsen if you’re dehydrated. Make sure to drink plenty of water to keep your skin hydrated and help it heal faster.
What to Do if You Experience Severe Itching or Rash:
In most cases, skin irritation caused by plankton exposure is mild and can be treated with over-the-counter remedies. However, if you experience severe symptoms, such as swelling, blisters, or intense pain, it’s important to seek medical advice. In rare cases, individuals may have an allergic reaction to marine toxins, which requires immediate medical attention.
Conclusion
The next time you take a dip in the sea after it rains, it’s good to be aware of the plankton blooms and marine stingers that could cause irritation to your skin. While the discomfort is usually temporary, taking steps to protect your skin and understanding the reasons behind the itchiness can make your beach experience more enjoyable. Remember to shower after swimming, wear protective clothing, and treat any irritation promptly to keep your skin healthy and irritation-free.
