If there is no light, the beach at night will be pitch black, but in the middle of summer, the sea will be fluorescent, and the waves will constantly flash blue-green light, looking beautiful, isn't it magical?
In August and September this year, many people saw the fluorescence in the waves under the night on the shore of Qingdao Laoshan Mountain, with the surge of the waves, very magical world feeling, this phenomenon is called "fluorescent sea", also known as "blue tears", not only near Qingdao, almost all over the coast of China will appear, in May and June this year, Fujian Xiamen and other places appear fluorescent sea, and Dalian near the sea also often appears this phenomenon, it can be said that most of the urban areas along the coast of our country can be witnessed, The same is true for coastal areas abroad.
So why does the phenomenon of "fluorescent sea" appear at night in the sea? In fact, the fluorescence in the seawater comes from the luminous algae growing in the seawater, it is an algae that can fluoresce at night, mostly spherical, and it should be very cute to think of, but in fact, it is not popular, because people often say that the red tide that appears in the sea is actually it.
When the seawater is eutrophicated, this algae can be multiplied in large quantities in the seawater, so it can form a red tide, the red tide can make the seawater hypoxia, the survival of other organisms in the seawater is challenged, and this algae is very small, between 0.1 and 2 mm in volume, they can enter the gill holes of fish, shrimp and shellfish with the flow of water, resulting in difficulty in breathing or even unable to breathe, so the appearance of fluorescent seas is not a good phenomenon, when the red tide appears in a large area, fish and shrimp in the same sea area may die in large quantities. Fishermen certainly don't like it, and it can take a huge toll on marine fisheries.
However, not all the algae that can cause red tide are luminous algae, because at least 180 kinds of plankton can cause red tide, and luminous algae is only one of them, but it is the one that is most likely to cause red tide. And the reason why this algae can produce fluorescence at night is because luminous algae emit light when stimulated, because its cytoplasm contains a large number of luciferin particles, essentially a lipoprotein, pink, which is why they gather in large quantities to form a red tide, and when luminous algae cells are stimulated, these luminous particles begin to shrink and produce light blue fluorescence, in the absence of other light at night, when the number of luminous algae per liter of seawater is about 200, We can see a faint blue fluorescence, and when the number of luminous algae reaches 1,000 to 2,000 per liter, the phenomenon of "fluorescent sea" will be very obvious.
In addition, the Heath's curved throat sea firefly can also trigger the "fluorescent sea" phenomenon, it is a mesozoite, the body contains fluorescein, when stimulated, it will also emit light, the size of this small animal is between 1 and 4 cm, the luminescence can be seen alone, but the light emitted by these two organisms is cold light, and will not increase the temperature of the seawater.
Resources:
"Qingdao Traffic Broadcasting Network" September 6 article "Qingdao surprised the "fluorescent sea"? The waves come with a magical blue light