Крупное соленое озеро Урмия, расположенное на Армянском нагорье в Иране, стало кроваво-красным. NASA Earth Observatory представила снимки, сделанные спектрорадиометром MODIS 23 апреля и 18 июля 2016 года, на которых видны произошедшие изменения.
Red Lake Urmia Like the Aral Sea, Iran’s salty Lake Urmia has shrunk rapidly during the past few decades. As it grows smaller, the lake grows saltier. And as it grows saltier, microscopic organisms are periodically turning the water striking shades of red and orange. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite recently captured a transition in the color of Lake Urmia between April and July 2016. On April 23, (left image) the water was green; by July 18, it was the color of wine. The shoreline is encrusted with salt deposits and appears white. Note that the ring of salt is especially noticeable in July, when water levels were lower. The color changes have become common in the spring and early summer due to seasonal precipitation and climate patterns. Spring is the wettest season in northwestern Iran, with rainfall usually peaking in April. Snow on nearby mountains within the watershed also melts in the spring. The combination of rain and snowmelt sends a surge of fresh water into Lake Urmia in April and May. By July, the influx of fresh water has tapered off and lake levels begin to drop. The fresh water in the spring drives salinity levels down, but the lake generally becomes saltier as summer heat and dryness take hold. That’s when the microorganisms show their colors, too. Careful sampling of the water would be required to determine which organisms transformed the lake in 2016, but scientists say there are likely two main groups of organisms involved: a family of algae called Dunaliella and an archaic family of bacteria known as Halobacteriaceae. Note that in July 2016, the color of the lake (and thus salinity levels) appeared to be relatively constant, despite the presence of a highway causeway. While there has been concern that the causeway would make it difficult for water to circulate between the northern and southern arms of the lake—as is the case in the Great Salt Lake of Utah—the effect in Lake Urmia is not nearly as noticeable. http://go.nasa.gov/2aevkrs @nasa #earthnow #nasaearth #lakeurmia #urmia #iran
За последние десятилетия озеро сильно обмелело. Кроме того, вода становится более соленой. И в июле микроорганизмы окрашивают его в красный или оранжевый цвет. За это ответственны одноклеточные водоросли Dunaliella salina и бактерии Halobacteriaceae.