Algal blooms are large concentrations of algae that grow in warm waters of oceans, lakes and rivers. They are often harmful to marine life, and some bloom varieties can be toxic to humans.
Blooms that grow exceptionally large are also proving to be harmful to economies that rely on tourism. They can wash up on shore, and form large piles on beaches. As water temperatures around the world slowly creep higher, more and more algae blooms are affecting wildlife and people negatively.
Facts about Algal Blooms
- They tend to form in warm waters such as the Gulf of Mexico during the summer months.
- Some types are toxic to humans, while others are not.
- Algal blooms cause the surrounding water to turn different shades of color, depending on the type of plant.
- Scientists are researching ways to solve large blooms, including the use of shellfish.
- Red tide is a variety of bloom that is toxic to humans.
What causes Algal Blooms?
An algal bloom, also called an algae bloom, is a phenomenon that happens when algae plants (simple aquatic plants) multiply quickly. This can happen in both fresh water and salt water marine environments. Depending on the type of algae involved, the water in the surrounding area will turn a different color based on the pigmentation of the algae.
Red tide, and algal blooms in general, are highly affected by surrounding atmospheric conditions and water temperatures. They require a specific temperature range to thrive, and they will disappear if the water temperature is no longer right for growth.
Where do they occur?
These phenomena are most common in places where water temperatures are warmer, such as the gulf coasts of Mississippi, Alabama and Florida during the summer months. They also occur in the warm waters of Caribbean, and can be found in East Asia, Africa, and as far north as Canada.
As average water temperatures across the US and Caribbean have been slowly rising over the past few decades, scientists have noticed an increase in the rate of blooms in these and other areas, as well as their severity.
Are they toxic to people and wildlife?
Since they are caused by different types of algae, they vary in toxicity and consequently, their potential to cause harm and damage. Some, such as red tide, are highly toxic, while others are benign and cause minimal harm.
Some are even good for the surrounding environment. When tiny algae plants die and decompose, they become a great source of food for other animals in the ocean, lake, or other body of water. The algae even plays a major role in the ocean food web by providing sustenance for organisms higher up on the food chain.
However, blooms can also harm the surrounding marine environment as it dies and decomposes. They can deprive water of oxygen levels. This drop in oxygen causes other marine life to either die or leave the area. Decaying algae can form a thick layer on the surface, which prevents crucial sunlight from reaching the floors of oceans, lakes, or rivers.
One of the most well-known types of harmful algae blooms is red tide, which occurs in Florida’s Gulf Coast just about every summer. As evidenced from the name, this algae bloom is named for the bright red color that the algae creates.
Red tide is caused by microscopic toxic algae known as Karenia brevis. When consumed by birds, marine mammals, and fish, the toxic algae can be deadly. It can also cause harm in people who eat contaminated shellfish or who have pre-existing respiratory conditions.
Since wind and ocean currents can carry the algae, people who are onshore can also be affected. People may report having trouble breathing if they are on a beach near an affected area.
Mote Marine Laboratory notes that it is important to pay attention to the color of surrounding water, whether large numbers of dead fish are in the area, and whether others near the beach are experiencing irritation. If these conditions are present, red tide may be as well and the area should be avoided.
Scientists are researching various methods to keep large blooms from happening. Some preliminary research has found that algal blooms are more prominent in areas where there has been a decline in shellfish levels, especially oysters. Efforts to re-grow shellfish populations have shown potential for controlling harmful algal blooms.
The Everglades Foundation is offering a $10 Million Dollar Prize, called the George Barley Water Prize to the person or group that figures out how to solve algal blooms cheaply.