- Although these microscopic organisms are among the ocean’s smallest, their “blooms” are often visible from space.
- Phytoplankton are critical to making the planet livable and contribute to the global carbon cycle as key producers of oxygen.
- The composition of phytoplankton blooms may be changing over time with warmer sea surface temperatures, scientists say.
- Phytoplankton can grow explosively over a few days or weeks, according to NASA.
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.
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.
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.
2023 Phytoplankton blooms
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.
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.
