National & Minnesota Report

Recent reports of a large seaweed blob transcending to Florida are the focus of local broadcasts, on CNN, MarketWatch, and Scientific American. The dimensions of the encroaching incursion are shown to be larger than the size of the United States. As spring break beckons and beachgoers from Minnesota and other agricultural states head south, they will not be experiencing the pristine white sand beaches of the east coasts of North and South Carolina, Georgia, and Florida, the Caribbean Islands, or as far as Mexico. This is due to the significant influx of Sargasso Seaweed, Phaeophyceae on the beaches.

The main problem is once the Sargassum gains landfall during high tides, and when rotting off gases’ hydrogen sulfide gas, leeches of ammonia, and also the accumulation of arsenic obtained through its journey. These toxins can irritate the eyes, nasal passages, and skin. The resulting chemicals release adversely affects marine life including fish, crustaceans, and corral. Even though it also provides habitat to various fish populations when it’s at sea.

This large detached mass was first documented in Christopher Columbus’s journal (1492) when his vessel the Santa Maria, and her sister ships the Nina and the Pinta, were becalmed for three days on their journey west. A combination of this vegetative material and the lack of wind stalled the exploration and raised fears amongst the crew of running aground and being prevented from returning to Spain.

Sargassum (Latin for kelp) is a brown naturally occurring belt of floating vegetation—due to the formation of air sacs—from the western coast of Africa to the USA. The material has been plaguing our eastern shores for decades and became more pronounced in 2011. This increase coincides with drought conditions in the agricultural belt which reduced water volumes in rivers and exposed the river bottoms to more churning activity and flushed out the muck and mire, thus releasing the chemicals temporarily sequestered. The main chemicals emanating from agricultural applications and those being nitrogen (N), phosphate (P), and potassium (K) or NPK.


This series of events combined with the regular dispersion of nutrient chemicals applied to fields and lawns in addition to chemical applications for ice melt on roadways all resulted in run-offs into the river basins. This has added to the nutrient enrichment flowing downstream from the Missouri, Ohio, Platte, Arkansas, Tennessee, and Red Rivers flowing into the Mississippi and spilling out in the Gulf of Mexico and out into the Atlantic Ocean via the Gulf Stream.

As yields of corn, cotton, soybeans, rice, wheat, and oats have increased, so has the application of higher amounts of NPKs in direct proportions. In recent years, some communities have eliminated the sale of lawn fertilizer containing Phosphorus, but this is not universal across the nation. As stated, the impact of the droughts has again re-exposed the older chemical deposits.

Additionally, on the Gulf of Mexico side of Florida, another type of Harmful Algae Bloom (HAB) is Karenia brevis, which forms Red Tides, but the question of whether increased NPKs have impacted these algae blooms. This is a common response and is often determined by who commissioned the study. Conflicting information often has resulted in the creation of the term non-source point pollution, but as technology and chemical markers are known, is it really a non-point source?

This coupled with increasing temperatures caused by climate change and the warming of the Gulf of Mexico and the Atlantic provides a perfect environment for this overgrowth and its continued expansion.