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June 15, 2004 - (date of web publication)


LIBRARY #: G04-029

TRT: ###



RELEASE DATE: 05/14/04

PRODUCER: LIZ SMITH 301-286-1540

URL(S): http://www.gsfc.nasa.gov/topstory/2004/0602hurricanebloom.html

Synopsis: Despite dealing out overwhelming devastation on land, a hurricane reshuffles the water in its path and leaves a healthier ocean in its wake. Researchers at Johns Hopkins University ran a “magnifying glass” over 13 North Atlantic hurricanes from 1998-2001, pouring over ocean color data from the NASA SeaWiFS instrument on the SeaStar satellite, which indicates levels of chlorophyll, or the green pigment in plants. First observed in 1998 following Hurricane Bonnie, the satellite images consistently showed tiny microscopic ocean plants, called phytoplankton, bloomed following the storms.

As a hurricane passes over the tropical waters of the Atlantic, it draws up cold water from deep below the warmer surface – this process drives the power engine of the cyclone. As researchers have discovered though, this heat engine drives more than the hurricane itself. The colder water rising to the surface brings with it phytoplankton and nutrients necessary for life. These microscopic ocean plants then bloom in greater-than-average amounts. The study clearly found that the physical make-up of a storm directly relates to the amount of plankton produced. Bigger storm cause larger plankton blooms. And, more plankton produces more chlorophyll, and satellites can see that.

Right now, phytoplankton produce almost half the oxygen we breathe. Phytoplankton play a major role in our planet’s carbon cycle, sucking carbon dioxide from the air and eventually bringing it to the ocean floor. By stimulating these phytoplankton blooms, hurricanes can affect the ecology of the upper ocean. This research is a major step in the effort to monitor overall planetary health, from climate change to the rhythms of life in oceans and on land.

ITEM 1: Hurricanes Leave Colder Water in Their Wake

SOURCE: G03-055 “warm water fuels hurricane Isabel”

The engines driving hurricanes across the Atlantic require 82 'F or warmer sea surface temperatures to keep the storm running. As these cyclones pass over warm waters, they cause colder water to rise to the surface. NASA satellites that detect sea surface temperatures through clouds can demonstrate the change in water temperature left in a hurricane’s wake.

In this visualization, red and orange indicate water at 82 F or warmer. As Hurricane Fabian drives through a large patch of this water, it leaves a blue colder water trail behind. Needing to fuel up on warm water as well, Hurricane Isabel hits the same area and takes a different path, leaving another cold trail behind.

The Advanced Microwave Scanning Radiometer (AMSR-E) on board the Aqua satellite provided data for this animation from August 22 to September 17, 2003. AMSR-E was developed by National Space Development Agency (NASDA) of Japan.


ITEM 2: Colder Water Not the Only Change Left Behind

SOURCE: SVS – SeaWiFS stills of Isabel, change in sea color/phytoplankton

Hurricane-induced upwelling, the rising of cooler water to the ocean surface, also substantially affects plankton growth in the ocean. For two to three weeks following almost every storm, the SeaWiFS data showed greater-than-normal phytoplankton growth that was stimulated by the addition of nutrients brought up to the surface.

SeaWiFS took the following images of Hurricane Isabel on September 15th and 18th of 2003. As the hurricane passes, it leaves behind it a trail of plankton blooms, evident by the rapid change in chlorophyll amounts. The lighter blue areas in the hurricane’s wake represent higher amounts of chlorophyll.

SeaWiFS, or Sea-Viewing Wide Field of View Sensor, is the scientific portion of the OrbView-2 satellite, orbiting 423 miles above Earth.


ITEM 3: With Cold Water Upwelling Comes Carbon-Sucking Phytoplankton

SOURCE: Susan Twardy – New Animation of Hurricane passing and then plankton bloom. And G01-023 “Carbon Cycle in the Ocean”

Carbon is the root of all life on Earth, and as it circulates through our biosphere, the Earth's state of health responds. Whenever the size of phytoplankton colonies in the ocean changes, it affects the amount of carbon absorbed from the atmosphere. These blooms are highly dependent on surrounding environmental conditions.

As a hurricane passes over the tropical waters of the Atlantic, it draws up cold water from deep below the warmer surface. As the cooler water rises, it brings with it phytoplankton and nutrients necessary for life. These microscopic plants then bloom in higher than average amounts. Bigger storms cause larger plankton blooms and more plankton absorb a greater amount of carbon from our atmosphere.

As phytoplankton die, a major portion sink to the bottom of the ocean, becoming what oceanographers call "marine snow." This precipitation is one of several natural processes that contribute to Earth's carbon cycle. Scientists are still trying to determine how much carbon dioxide might be removed by such a process.


ITEM 4: Planet-Wide Plankton Blooms

SOURCE: G01-023 “Spring Bloom in the Atlantic”

Using five years of continual data from the SeaWiFS instrument, scientists have taken the Earth’s pulse. Every spring, phytoplankton spread across the North Atlantic in one of the largest “blooms” on the planet. These explosive annual growths keep Earth’s carbon-based circulatory system flowing like a heartbeat. In this visualization, the phytoplankton colony shown in green covers an area larger than the Amazon rainforest in South America.


ITEM 5: Small-sized Friends, Super-sized Effects

SOURCE: G01-023 “Think Small”

Phytoplankton may be humankind’s smallest friend. These microscopic single-celled organisms are the foundation for the oceanic food chain. Our oceans teem with them. Despite their size, they play a major role in the carbon cycle affecting every form of life on Earth. Right now, tiny phytoplankton produce almost half the oxygen you breathe.


ITEM 6: Hurricane B-Roll

SOURCE: G03-036 “Hurricane Mitch” and “Hurricane Floyd Grows Nasty”

Clip A: Hurricane Mitch was the deadliest hurricane on record and took over 10,000 lives worldwide. This 3-D video sequence shows it approaching the Mexican coastline, October 26-27, 1998
Clip B: Hurricane Floyd was the third-most costly hurricane on record to hit the U.S. These sequences show its development and landfall from September 12-15, 1999. The video was enhanced at the NASA GSFC Laboratory for Atmospheres.
Data for both clips came from NOAA/National Weather Services' Geostationary Operational Environmental Satellite (GOES)-8.


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