Category : Natural History

Natural History / Natural History - 4 years ago

What are the horse latitudes?

The horse latitudes are regions located at about 30 degrees north and south of the equator. These latitudes are characterized by calm winds and little precipitation. The horse latitudes are located at about 30 degrees north and south of the eq...

Natural History / Natural History - 4 years ago

Are horseshoe crabs really crabs?

Horsehoe crab mating season, Lewes, Delaware. Image credit: Jacqueline Bedell Despite their common name, horseshoe crabs are not really crabs (crustaceans). Atlantic horseshoe crabs (Limulus polyphemus), which swarm U.S. coastlines each summer...

Natural History / Natural History - 4 years ago

What are PBDEs?

As part of NOAA's Mussel Watch Program, PBDEs are one of 150 different contaminants that are continually monitored by periodically sampling bivalves and sediment at 300 coastal sites around the nation. PBDEs are found in a variety of consumer...

Natural History / Natural History - 4 years ago

When Was the First Earth Day?

Firefighters battle a fire on Ohio's Cuyahoga River in 1952. The polluted river caught fire on several occasions between 1936 and 1969, when debris and oil had concentrated on the water's surface and ignited. A blaze in 1969 came at a time of inc...

Natural History / Natural History - 4 years ago

What is a pelagic fish?

Oceanic pelagic fish, such as the tuna pictured above, have agile bodies made for long distance migration. Many oceanic pelagic fish travel in schools while some are solitary that drift with ocean currents. Pelagic fish can be categorized as c...

Natural History / Natural History - 4 years ago

What is bombogenesis?

Fourteen of 20 hurricane-force wind events underwent bombogenesis in the North Atlantic during the first two months of 2014. This unusual activity can be seen in wind speed data from the period. In this image, blues indicate areas with wind speed...

Natural History / Natural History - 4 years ago

What do geodesists do?

Geodesists measure and monitor the Earth’s size and shape, geodynamic phenomena (e.g., tides and polar motion), and gravity field to determine the exact coordinates of any point on Earth and how that point will move over time. Using a wide var...

Natural History / Natural History - 4 years ago

What is an anchialine pool?

 Anchialine pools form some of the longest submerged caves structures on Earth. (Image courtesy of National Science Foundation) The word “anchialine” (AN-key-ah-lin) comes from a Greek word meaning “near the sea." These typically small pools,...

Natural History / Natural History - 4 years ago

What is an artificial reef?

Can you spot the sunken ship? In June 2002, the retired USS Spiegel Grove  was sunk in waters off Key Largo. At 510 feet (155.45 meters) long, the ship was, at the time, the largest vessel ever intentionally scuttled for the purpose of creating an...

Natural History / Natural History - 4 years ago

Are there oceans on other planets?

Europa is thought to have subsurface liquid water. Scientists hypothesize that Europa's hidden ocean is salty, tidal, and causes its ice surface to move, resulting in large fractures which are clearly visible in the above image. Although Europa i...

Natural History / Natural History - 4 years ago

What is dredging?

As sand and silt washes downstream, sedimentation gradually fill channels and harbors. This material must be periodically removed by dredging. Dredging is the removal of sediments and debris from the bottom of lakes, rivers, harbors, and other...

Natural History / Natural History - 4 years ago

What is a slough?

South Slough is a 4,771-acre National Estuarine Research Reserve located on Coos Bay Estuary in Oregon (Image credit: South Slough NERR). A slough is typically used to describe wetlands. Sloughs along the edges of rivers form where the old cha...

Natural History / Natural History - 4 years ago

Is the Earth round?

This NASA image shows Earth from space. The image is a combination of data from two satellites. The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA’s Terra satellite collected the land surface data over 16 days, while...