Sparkling ocean 'glows up' each summer: Why bioluminescence occurs and where to see it

Camille Fine, USA TODAY
·3 min read
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Microscopic plant-like organisms that form dazzling turquoise displays in shallow waters have returned as spring in North America transitions into a wet summer.

Sunlight and warm temperatures in the North Sea, between Scotland and Norway, have enabled phytoplankton to come to life this month, choking ocean waters with thick, slick-forming cyanobacteria blooms in one of nature’s “most amazing phenomena,” according to NOAA.

Bioluminescence, a chemical reaction most commonly seen in marine organisms, causes light to emit from living things. When these organisms are moved by waves or the paddle of a kayak or canoe, the light becomes visible. Most marine and land organisms' bioluminescence appears blue-green, however, some land species, such as fireflies, beetle larvae, and even mushrooms, also glow yellow.

The bloom might contain an abundance of a kind of phytoplankton commonly referred to as sea sparkle, according to National Park Service, which makes the water appear milky blue in satellite imagery, NASA said. However, without a physical sample, "it’s not possible to say for sure which type of phytoplankton are present in these images," NASA Earth Observatory said on June 20.

Spectators watch bioluminescent plankton light up the shoreline as they churn in the waves at Dockweiler State Beach during the coronavirus outbreak, Wednesday, April 29, 2020, in Los Angeles, Calif. (AP Photo/Mark J. Terrill)
Spectators watch bioluminescent plankton light up the shoreline as they churn in the waves at Dockweiler State Beach during the coronavirus outbreak, Wednesday, April 29, 2020, in Los Angeles, Calif. (AP Photo/Mark J. Terrill)
Abundant phytoplankton swirled in the waters off the U.S. Mid-Atlantic coast in spring 2023.
Abundant phytoplankton swirled in the waters off the U.S. Mid-Atlantic coast in spring 2023.

Phytoplankton typically peak at these latitudes around the summer solstice and are most abundant in the North Sea in late spring and early summer; when high levels of nutrients are available in the water — a product of increased runoff from European rivers, intense seasonal winds and rain.

notice the seasonal abundance of chlorophyll off the coast of Argentina. This area, known as the “shelf-break front,” is at a crossroads of ocean currents. The nutrients they carry often produce dazzling phytoplankton displays in the spring and summer. These blooms are especially eye-catching in natural-color satellite images. As summer approached in the southern hemisphere, a phytoplankton bloom became visible off the coast of Argentina. This image was acquired on November 21, 2022, with the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. Turbulent conditions on the edge of the continental shelf generated swirls of water traced by phytoplankton that painted the water blue and green.

Hints of the the bloom developed for about two weeks and became visible to the NOAA-20 on June 15, NASA said.

"The appearance of the blooms is similar to those created by Noctiluca scintillans (which means glistening night light) — a type of marine dinoflagellate known to live in this area in the summer," NASA said. "Though Noctiluca scintillans blooms can glow at night in beautiful ways, their presence can also soak up oxygen from the water and cause hypoxia and dead zones."

Photographs shows the luminous glow the phytoplankton can produce.

A surfer rides a wave as bioluminescent plankton lights up the surf around him April 30, 2020, in Newport Beach, Calif.
A surfer rides a wave as bioluminescent plankton lights up the surf around him April 30, 2020, in Newport Beach, Calif.
The Pier is seen as bioluminescent waves crash on the sand, shining with a blue glow on April 28, 2020, in Manhattan Beach, California.
The Pier is seen as bioluminescent waves crash on the sand, shining with a blue glow on April 28, 2020, in Manhattan Beach, California.
People stand on the beach at night to watch the waves glow blue due to bioluminescence on April 24, 2020 in Newport Beach, California.
People stand on the beach at night to watch the waves glow blue due to bioluminescence on April 24, 2020 in Newport Beach, California.

2023 Phytoplankton blooms

On June 14, 2023, the Operational Land Imager-2 (OLI) on Landsat 9 acquired this natural-color image of a bloom north of the East Frisian Islands in Lower Saxony, Germany. The bloom became visible in natural-color MODIS imagery in late May and drifted in the area through mid-June. The grids of dots within and just east of the phytoplankton are turbines that are part of an offshore wind farm.
The Operational Land Imager (OLI) on the Landsat 8 satellite captured this image of an algal bloom on Lake Villarrica in Chile on May 2, 2023. Ground-based observations and analysis of additional satellite images suggest that cyanobacteria make up the light blue-green swirls in the natural-color image.
The Operational Land Imager (OLI) on the Landsat 8 satellite captured this image of an algal bloom on Lake Villarrica in Chile on May 2, 2023. Ground-based observations and analysis of additional satellite images suggest that cyanobacteria make up the light blue-green swirls in the natural-color image.
Satellites observed hints of the bloom developing between Scotland and Norway for about two weeks, but the view from above was mostly hidden by clouds. Then, mostly clear skies on the afternoon of June 15, 2023, allowed the Visible Infrared Imaging Radiometer Suite (VIIRS) on the NOAA-20 satellite to acquire this natural-color image of the abundant phytoplankton.

When and where can I see bioluminescence?

According to the National Park Service, the best times for viewing bioluminescence are in the summer and fall on dark, cloudy nights before the moon has risen or after it sets. In the Gulf of Alaska, nutrient-rich water provides fertile conditions for phytoplankton blooms, according to NASA.

Tomales Bay State Park in northern California, Vieques National Wildlife Refuge in Puerto Rico, Olympic Coast National Marine Sanctuary in Washington and bays near Acadia National Park in Maine are just a few of the popular bodies of water to see bioluminescence in the United States.

The phenomenon can also be seen anywhere along the National Seashore's coastline, according to National Park Service.

Dinoflagellates, which are single-celled marine phytoplankton, emit an electric blue light when stirred up during a 2015 algae bloom in the Indian River Lagoon. A kayaker plied the waters at Little Mud Creek in St. Lucie County on Sept. 30, 2015.
Dinoflagellates, which are single-celled marine phytoplankton, emit an electric blue light when stirred up during a 2015 algae bloom in the Indian River Lagoon. A kayaker plied the waters at Little Mud Creek in St. Lucie County on Sept. 30, 2015.

Phytoplankton blooms are changing

In a 21-year study, researchers in Norway found that phytoplankton blooms in the region were starting later in the year and lasting slightly longer. The cause of this delay is unclear, but researchers say that warmer sea surface temperature could be changing the composition of phytoplankton blooms.

Between 2000 and 2020, blooms in the North Sea lasted, on average, about 46 days, peaking in mid-to-late April.

Bioluminescent plankton light up the shoreline as they churn in the waves in front of an empty lifeguard station at Dockweiler State Beach during the coronavirus outbreak, Sunday, April 26, 2020, in Los Angeles, Calif.
Bioluminescent plankton light up the shoreline as they churn in the waves in front of an empty lifeguard station at Dockweiler State Beach during the coronavirus outbreak, Sunday, April 26, 2020, in Los Angeles, Calif.

This article originally appeared on USA TODAY: What causes bioluminescence in ocean? Why marine life glows in summer