What is the Mysterious Brown Ribbon Spreading from the Atlantic Ocean to the Gulf of Mexico? Check Here!

A mysterious brown ribbon has been spotted stretching from the Atlantic Ocean to the Gulf of Mexico. It's not a snake, but it looks like one from above. This long, winding trail is actually made of sargassum—a type of brown seaweed. Sargassum floats on the ocean's surface, forming thick mats that can stretch for miles. It's natural and usually harmless, but when it accumulates on beaches, it emits an unpleasant odour and can impact tourism and marine life.

This brown ribbon has grown bigger in recent years. Scientists believe that warmer waters and pollution may be contributing to the spread of this disease. Boats and fish can get trapped in it, and it blocks sunlight from reaching coral reefs. In this article, we'll take a look at what sargassum is, why it's spreading so fast, and how it affects people and nature.

What Is the Brown Ribbon Seen in the Ocean?

The "brown ribbon" often seen in the ocean, particularly in the Atlantic, is most likely a massive belt of Sargassum algae. This phenomenon is sometimes referred to as the Great Atlantic Sargassum Belt (GASB), and it has become a significant concern in recent years.

Here are the key points about it:

• What it is: Sargassum is a genus of large brown seaweed (a type of algae) that floats in vast, island-like masses or long lines (ribbons) on the ocean's surface. It's unique because it's pelagic, meaning it floats freely and doesn't attach to the seafloor.
• Location: The Great Atlantic Sargassum Belt spans the Atlantic Ocean, extending from the West African coast to the Gulf of Mexico.
• Appearance: From above, or in satellite images, these significant accumulations of brown algae can look like a massive, continuous brown ribbon or snake stretching for thousands of kilometres.
• Ecological Role: In the open ocean, it provides a crucial floating habitat, food, and nursery ground for a variety of marine life, including fish, sea turtles, crabs, and shrimp.
• The Problem: In recent years, the amount of Sargassum has dramatically increased (known as a "bloom"). When these massive amounts wash ashore, they can cause significant problems:
• Ecological Harm: They can smother coral reefs and seagrass beds, and their decomposition in the water removes oxygen, potentially causing fish kills.
• Economic Impact: They disrupt the tourism and fishing industries, and the decaying algae on beaches releases foul odours and harmful gases, such as hydrogen sulfide.

How Does This Seaweed Affect People and Marine Life?

The mass spread of Sargassum has a dual impact, shifting from a beneficial floating habitat in the open ocean to a significant environmental, health, and economic crisis when it washes up on coasts.

Effects on People (Human Health and Economic)

• Irritation: Eye, nose, and throat irritation.
• Respiratory Problems: Nausea, headaches, and vertigo are hazardous for people with asthma or other respiratory conditions.
• Chronic/Severe Effects: Prolonged exposure may lead to neurocognitive impacts, and at high, confined concentrations, it can be hazardous. 

Other Hazards:

• Ammonia: Also released during decomposition, irritating.
• Heavy Metals: Sargassum can bioaccumulate toxic heavy metals (such as arsenic and cadmium) from the water, posing a risk if the seaweed is used for food/feed or if it contaminates coastal waters and seafood.
• Stinging Organisms: The floating mats can harbour small organisms, like jellyfish larvae, which may cause skin irritation or rashes upon contact. 
• Economic & Tourism Collapse: Beaches become unsightly, smelly, and inaccessible, driving away tourists and causing massive revenue losses for coastal economies, especially in the Caribbean.
• Cleanup Costs: Removal of the immense biomass from beaches is costly, labour-intensive, and often requires heavy machinery, which can damage the delicate beach ecosystem and cause erosion.
• Infrastructure Damage: Hydrogen sulfide gas can corrode metals, causing damage to infrastructure near the coast, including air conditioning units, power plants, and desalination plants.
• Fisheries: Fishing is disrupted as mats entangle boat propellers, clog ports, and can displace or kill fish in nearshore waters. 

Effects on Marine Life and Ecosystems

Why Is Sargassum Spreading Across the Atlantic and Gulf?

The rapid spread of Sargassum—a free-floating brown seaweed—across the Atlantic and into the Gulf of Mexico, forming what is known as the Great Atlantic Sargassum Belt (GASB), is driven by a combination of factors, primarily:

• Increased Nutrient Input (Pollution): This is considered a major driver of the massive, recent blooms:
• Terrestrial Runoff: Increased nutrient-rich pollution, particularly nitrogen and phosphorus, from land-based sources like agricultural runoff (fertilisers), sewage, and wastewater discharge flows into the ocean.
• River Discharge: Major rivers, most notably the Amazon River, as well as others like the Congo and Mississippi, discharge significant loads of these nutrients into the tropical Atlantic.
• Atmospheric Deposition: Airborne nutrients, such as iron and phosphates from Saharan dust blowing westward across the Atlantic, can also contribute to the growth.

Climate and Ocean Dynamics:

• Ocean Warming: Warmer sea surface temperatures in the tropical Atlantic and Caribbean may contribute to the faster growth of Sargassum.

Changes in Ocean Circulation and Winds:

• An unusual climatic event, such as a substantial shift in the North Atlantic Oscillation (NAO) around 2009-2010, is believed to have initially transported Sargassum from its historic home in the Sargasso Sea southward into the nutrient-rich tropical Atlantic, where the blooms first took hold in 2011.
• Ocean Currents (such as the Gulf Stream, Loop Current, and others) and Trade Winds then act to aggregate and transport the massive mats of seaweed across the Atlantic and into the Caribbean and the Gulf of Mexico.
• Seasonal changes in wind patterns cause vertical mixing of ocean layers, bringing deeper, nutrient-rich water to the surface, which fuels the bloom in the central Atlantic.