A diatom is any member of a large group comprising several genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of the Earth's biomass: they generate about 20 to 50 percent of the oxygen produced on the planet each year, take in over 6.7 billion tonnes of silicon each year from the waters in which they live, and constitute nearly half of the organic material found in the oceans. The shells of dead diatoms can reach as much as a half-mile deep on the ocean floor, and the entire Amazon basin is fertilized annually by 27 million tons of diatom shell dust transported by transatlantic winds from the African Sahara, much of it from the Bodélé Depression, which was once made up of a system of fresh-water lakes.
Long Island Sound is a marine sound and tidal estuary of the Atlantic Ocean. It lies predominantly between the U.S. state of Connecticut to the north and Long Island in New York to the south. From west to east, the sound stretches 110 mi (180 km) from the East River in New York City, along the North Shore of Long Island, to Block Island Sound. A mix of freshwater from tributaries, and saltwater from the Atlantic Ocean, Long Island Sound is 21 mi (34 km) at its widest point and varies in depth from 65 to 230 feet.
The Maumee River is a river running in the United States Midwest from northeastern Indiana into northwestern Ohio and Lake Erie. It is formed at the confluence of the St. Joseph and St. Marys rivers, where Fort Wayne, Indiana has developed, and meanders northeastwardly for 137 miles (220 km) through an agricultural region of glacial moraines before flowing into the Maumee Bay of Lake Erie. The city of Toledo is located at the mouth of the Maumee. The Maumee was designated an Ohio State Scenic River on July 18, 1974. The Maumee watershed is Ohio's breadbasket; it is two-thirds farmland, mostly corn and soybeans. It is the largest watershed of any of the rivers feeding the Great Lakes, and supplies five percent of Lake Erie's water.
The rainbow trout is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead is an anadromous (sea-run) form of the coastal rainbow trout(O. m. irideus) or Columbia River redband trout (O. m. gairdneri) that usually returns to freshwater to spawn after living two to three years in the ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are also called steelhead.
This is a timeline of environmental history of New Zealand. It includes notable events affecting the natural environment of New Zealand as a result of human activity.
The Monocacy River is a free-flowing left tributary to the Potomac River, which empties into the Atlantic Ocean via the Chesapeake Bay. The river is 58.5 miles (94.1 km) long, with a drainage area of about 970 square miles (2,500 km2). It is the largest Maryland tributary to the Potomac.
The Motueka River is located in the north of the South Island of New Zealand and is a popular tourist destination for watersports and fishing. The Motueka flows 116 kilometres (72 mi) from the mountains 40 km west of the city of Nelson in the southeast of the catchment and flows north to the Tasman Bay.
The Tekapo River flows occasionally through the Mackenzie Basin, Canterbury, in New Zealand's South Island, although the riverbed is now often dry in the upper reaches. It maintains a constant flow below the confluence of several tributaries, notably the Maryburn, Forks, and Grays rivers.
A number of introduced species, some of which have become invasive species, have been added to New Zealand's native flora and fauna. Both deliberate and accidental introductions have been made from the time of the first human settlement, with several waves of Polynesian people at some time before the year 1300, followed by Europeans after 1769.
The Wallkill River, a tributary of the Hudson, drains Lake Mohawk in Sparta, New Jersey, flowing from there generally northeasterly 88.3 miles (142.1 km) to Rondout Creek in New York, just downstream of Sturgeon Pool, near Rosendale, with the combined flows reaching the Hudson at Kingston.
Mattawoman Creek is a 30.0-mile-long (48.3 km) coastal-plain tributary to the tidal Potomac River with a mouth at Indian Head, Maryland, 20 miles (32 km) downstream of Washington, D.C. It comprises a 23-mile (37 km) river flowing through Prince George's and Charles counties and a 7-mile (11 km) tidal-freshwater estuary in Charles County. About three-fourths of its 94-square-mile (240 km2) watershed lies in Charles County, with the remainder in Prince George's County immediately to the north.
The New Zealand mud snail is a species of very small freshwater snail with a gill and an operculum. This aquatic gastropod mollusk is in the family Tateidae.
Lake Needwood is a 75-acre (300,000 m2) reservoir in Derwood, Maryland, United States. Located east of Rockville, in the eastern part of Montgomery County, it is situated on Rock Creek. The lake was created by damming Rock Creek in 1965 with the goal of providing flood control and reducing soil erosion. Lake Needwood also protects the water quality of the creek by functioning as a retention basin to trap sediment from storm-water runoff.
The term fish kill, known also as fish die-off, refers to a localized die-off of fish populations which may also be associated with more generalized mortality of aquatic life. The most common cause is reduced oxygen in the water, which in turn may be due to factors such as drought, algae bloom, overpopulation, or a sustained increase in water temperature. Infectious diseases and parasites can also lead to fish kill. Toxicity is a real but far less common cause of fish kill.
Stillman Creek, also known during different eras as Mud Creek, Old Man's Creek, Sycamore Creek, and Stillman's Run, is part of the Rock River watershed, and located in Ogle County, Illinois, United States. The stream was named for Isaiah Stillman, who also lent his name to the village of Stillman Valley, Illinois, which lies along the creek.
A harmful algal bloom (HAB), or excessive algae growth, is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, mechanical damage to other organisms, or by other means. HABs are sometimes defined as only those algal blooms that produce toxins, and sometimes as any algal bloom that can result in severely lower oxygen levels in natural waters, killing organisms in marine or fresh waters. Blooms can last from a few days to many months. After the bloom dies, the microbes that decompose the dead algae use up more of the oxygen, generating a "dead zone" which can cause fish die-offs. When these zones cover a large area for an extended period of time, neither fish nor plants are able to survive. Harmful algal blooms in marine environments are often called "red tides".
The Mad River is a tributary to the Winooski River in Vermont. It has its headwaters in Granville Gulf, then flows north through the towns of Warren, Waitsfield, and Moretown before entering the Winooski River just downstream from Middlesex. Other towns within the Mad River watershed are the entire Town of Fayston and a portion of the Town of Duxbury. Relative to other rivers in the state, the Mad River is fairly rocky and clear, making it a popular for swimming. In the summer of 2008, didymo, or Rock Snot, was found in the upper portions of the river.
Castle Rock Lake is an artificial lake on the Wisconsin River. It is located in central Wisconsin in Adams County and Juneau County. The lake has an inflow from Petenwell Lake, Yellow River, Big Roche a Cri., and Klien Creek. It has a surface area of 16,640 acres (67.3 km2) and its depth varies from 8–20 ft (2.4–6.1 m) in most places, with area in the old river beds reaching as deep as 35 ft (11 m).
In 2004 Didymosphenia geminata, a diatom commonly known as didymo or rock snot, was discovered in New Zealand, the first time it was found in the Southern Hemisphere. To restrict its spread, the whole of the South Island of New Zealand was declared a controlled area in December 2005. All items, such as boats, fishing gear, clothing, and vehicles, that have been in a stream, river or lake, must be cleaned before they enter another waterway. Biosecurity New Zealand working with Environment Southland, AgriQuality and Fish and Game New Zealand launched an extensive public awareness campaign to encourage river users to clean their equipment after use in affected waterways. This campaign was highly successful, with 99% of freshwater users surveyed in 2008 in the South Island being aware of didymo.
Phytobenthos (from Greek φυτόν and βένθος are autotrophic organisms found attached to bottom surfaces aquatic environments, such as rocks, sediments, or even other organisms. This photosynthetic community includes single-celled or filamentous cyanobacteria, microalgae, and macrophytes. Phytobenthos are highly diverse, and can be found in freshwater and marine environments, as well as transitional water systems. However, their distribution and availability still depend on the factors and stressors that exist in the environment. Because phytobenthos are autotrophs, they need to be able to subsist where it is still possible to perform photosynthesis. Similar to phytoplankton, phytobenthos contribute to the aquatic food web for grazers and heterotrophic bacteria, and researchers have also been studying their health as an indicator for water quality and environmental integrity of aquatic ecosystems.
