Earth Snapshot RSS Feed Twitter

Posts tagged Algae

Algal Blooms in Caspian Sea Near Volga Delta, Russia and Kazakhstan

45.7N 48.8E

October 18th, 2011 Category: Lakes, Rivers, Wetlands

Caspian Sea - October 12th, 2011

The brown and green fan-shaped area on the northwestern shores of the Caspian Sea, on the left side of this image, is the Volga Delta. It is the largest river delta in Europe, although the far eastern part of the delta lies in Kazakhstan.

Industrial and agricultural modification to the delta plain has resulted in significant wetland loss. Between 1984 and 2001, the delta lost 277 km² of wetlands, or an average of approximately 16 km² per year, from natural and human-induced causes. The Volga discharges large amounts of industrial waste and sediment into the relatively shallow northern part of the Caspian Sea. The added fertilizers nourish the algal blooms that grow on the surface of the sea, allowing them to grow larger. These algal blooms appear bright green in this image.

Ice and Sediments in Lake Michigan, USA – April 21st, 2010

43.4N 87.2W

April 21st, 2010 Category: Image of the day, Lakes

USA - March 5th, 2010

USA - March 5th, 2010

Lake Michigan is one of the five Great Lakes of North America, and the only one located entirely within the United States. It is bounded, from west to east, by the U.S. states of Wisconsin, Illinois, Indiana, and Michigan. Although this image focuses on the southern section of the lake, parts of all four states are visible. The city of Chicago is also situated on the southwestern shores.

The beaches of the lake’s western coast and the northernmost part of the east coast are rocky, while the southern and eastern beaches are sandy and dune-covered. This is partly because of the prevailing winds from the west which also cause thick layers of ice to build up on the eastern shore in winter. Here, ice can be observed along the southeastern coastline, while greenish sediments or algae border both the western and eastern shores.

Lake Huron’s Saginaw Bay in Michigan, USA

43.8N 83.6W

April 12th, 2010 Category: Lakes

USA - March 5th, 2010

USA - March 5th, 2010

Saginaw Bay (left) is a bay within Lake Huron (one of the Great Lakes) located on the eastern side of the USA state of Michigan. It forms the space between Michigan’s Thumb region and the rest of the Lower Peninsula of Michigan. Here, most of the bay appears covered in ice. Moving northeast, a greenish trail of algae or sediments is visible in the main body of Lake Huron.

Saginaw Bay is 1,143 square miles (2,960 km2) in area. It is located in parts of five Michigan counties: Arenac, Bay, Huron, Iosco, and Tuscola.The Saginaw Bay Watershed is the largest drainage basin in Michigan, draining approximately 15% of the total land area. The watershed contains the largest contiguous freshwater coastal wetland system in the United States.

Aquatic Vegetation on Lake Ouachita, Arkansas

34.5N 93.3W

March 24th, 2010 Category: Lakes

USA - March 5th, 2010

USA - March 5th, 2010

Lake Ouachita is a reservoir created by the damming of the Ouachita River by the Blakely Mountain Dam. The lake is located near Hot Springs, Arkansas, USA. It is completely surrounded by the Ouachita National Forest.

Lake Ouachita is the largest lake completely in Arkansas, as the larger Bull Shoals Lake extends into Missouri. Lake Ouachita has over 690 miles (1,110 km) of shoreline and over 40,000 acres (16,000 ha) of water.

A topic of debate is the vegetation that covers 10% of the lake. Lake Ouachita’s vegetation is being addressed by the U.S. Army Corps of Engineers, the Arkansas Game and Fish Commission, and the Lake Ouachita Association to control the hydrilla and Eurasian watermilfoil.

The goal of the project is to contain and reduce — not to eradicate — the vegetation, since the presence of aquatic vegetation in moderate amounts is beneficial to the lake’s fishery.

Green Waters Around Djerba and the Kerkennah Islands, Tunisia

33.8N 10.8E

November 13th, 2009 Category: Snapshots

Tunisia - September 24th, 2009

Tunisia - September 24th, 2009

The water around the shores of eastern mainland Tunisia, the island of Djerba (below) and the Kerkennah Islands (above), and in the Gulf of Gabès (center left) and Gulf of  Boughrara (below Djerba) show various shades of green, ranging from light and bluish to dark and brownish.

Some of the dark green color may be caused by two species of green algae that have a tendency of invading the coast of Tunisia and are often found around the Kerkennah Islands.