To safely transit marine highways that get busier with each passing year, mariners need the most accurate and up-to-date information they can find. Increasingly, they are finding that information on the nowCOAST Web site....

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A lunar day is how long it takes for one point on the Earth to make one complete rotation and end up at the same point in relation to the moon. The reason that a lunar day is longer than a normal 24-hour day is because the moon rotates around the Earth in the same direction that the Earth is spinning. It takes the Earth an extra 50 minutes to “catch up” to the moon.

Tides are very long waves that move across the oceans. They are caused by the gravitational forces exerted on the earth by the moon, and to a lesser extent, the sun. When the highest point in the wave, or the crest, reaches a coast, the coast experiences a high tide. When the lowest point, or the trough, reaches a coast, the coast experiences a low tide.

Imagine the ocean is shaped like a football pointing at the moon. The football’s pointed ends represent the parts of the Earth experiencing high tide and the football’s flat sides are the parts of the earth experiencing low tide.

The point facing the moon is formed because the gravitational pull of the moon is strongest on whichever side of the Earth faces it. Gravity pulls the ocean towards the moon and high tide occurs.

The bulge on the far side of the Earth is caused by inertia. The water moving away from the moon resists the gravitational forces that attempt to pull it in the opposite direction. Because the gravitational pull of the moon is weaker on the far side of the Earth, inertia wins, the ocean bulges out and high tide occurs.

As the Earth spins, different areas of the planet face the moon, and this rotation causes the tides to cycle around the planet.

NOS scientists advanced tidal recording systems as well as satellite imagery to monitor tides and water levels. These data are used to predict ocean behavior in order to protect our coasts and coastal communities.

For more information:
Center for Operational Oceanographic Products and Services
Tides Tutorial, NOS Education
What are Tides? - Diving Deeper audio podcast

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Phytoplankton, also known as microalgae, are similar to terrestrial plants in that they contain chlorophyll and require sunlight in order to live and grow. Most phytoplankton are buoyant and float in the upper part of the ocean, where sunlight penetrates the water. Phytoplankton also require inorganic nutrients such as nitrates, phosphates, and sulfur which they convert into proteins, fats, and carbohydrates.

The two main classes of phytoplankton are dinoflagellates and diatoms. Dinoflagellates use a whip-like tail, or flagella, to move through the water and their bodies are covered with complex shells. Diatoms also have shells, but they are made of a different substance and their structure is rigid and made of interlocking parts. Diatoms do not rely on flagella to move through the water and instead rely on ocean currents to travel through the water.

In a balanced ecosystem, phytoplankton provide food for a wide range of sea creatures including whales, shrimp, snails, and jellyfish. When too many nutrients are available, phytoplankton may grow out of control and form harmful algal blooms (HABs). These blooms can produce extremely toxic compounds that have harmful effects on fish, shellfish, mammals, birds, and even people.

The National Centers for Coastal Ocean Science conduct extensive research on harmful algal blooms. Scientists use a range of technologies to predict where and when HABs are likely to form and how they will affect the areas where they occur. Scientists use this information to inform coastal authorities on how to best respond in order to minimize negative impacts.

For more information:
NOAA's National Centers for Coastal Ocean Science
Phytoplankton -- What Are They?, Northwest Fisheries Science Center
Phytoplankton Monitoring Network
Harmful Algal Blooms

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Thirteen staff from the Office of Ocean and Coastal Resource Management’s Estuarine Reserves Division (ERD) recently got hands-on experience with nesting ospreys when they accompanied naturalist Greg Kearns as he banded some of the season’s newly hatched chicks in the Jug Bay component of the Chesapeake Bay Maryland National Estuarine Research Reserve....

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Seamounts are formed by volcanic activity and can be taller than 3,000 meters (10,000 feet).  They can be isolated or part of large mountain chains. The New England Seamount contains more than 30 peaks that stretch 1,600 kilometers (994 miles) from the coast of New England.

Seamounts often have a high level of biological productivity because they provide habitats for many species of plants and animals. Over 200 species of sea creatures have been observed at a single guyot in the New England Seamount. Seamounts are great locations to discover new species because each seamount houses different types of animals, including many that can only be found in guyot habitats.

Seamounts are home to many commercial fish and are therefore very beneficial to our economy. Seamounts are also important to the field of medicine, as any number of undiscovered species may lead to new drugs or medical treatments.

For more information:
Mountains in the Sea Exploration: No Escape (pdf, 1.2Mb), NOAA Ocean Explorer
Davidson Seamount, Office of National Marine Sanctuaries

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Although first observed in 1513 by Ponce de Leon, the Gulf Stream was not charted until the early 1770s by Benjamin Franklin, with the help of a Nantucket sea captain.

Around 1770, the Board of Customs in Boston, Massachusetts, noticed that packets travelling between Falmouth, Massachusetts, and New York, New York, by sea took two weeks longer to arrive than merchants travelling from London to Rhode Island. This was perplexing as Falmouth and New York were less than a day apart by road.

Franklin spoke with a sea captain who told him that while fishing for whales, he noticed that the whales would swim alongside the Gulf Stream, but never in it. Fishermen would frequently cross the Gulf Stream, where they passed packet ships sailing within, against the current. This was the reason for the delays. Franklin had the captain mark the location of the Gulf Stream, as well as the directions of its currents.

In 1843, the United States Coast Survey, NOAA’s earliest “ancestor”, set out to study the Gulf Stream in more detail. They wanted to determine the depth of the water, the temperature of the water at different depths, the characteristics of the ocean bottom, the direction and velocity of the currents at different depths, and the extent of plant and animal life. Their early observations led them to discover features such as cool and warm water banding, as well as the “Charleston Bump.”

For more information:
History of Ocean Exploration: Early Years (1807-1865), NOAA Ocean Explorer
1785: Benjamin Franklin's 'Sundry Maritime Observations', NOAA Ocean Explorer

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On June 11, hundreds of children from Washington, DC, descended on the National Mall to learn about the importance of protecting our nation’s watersheds through art....

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Ten years ago, a small plane piloted by the son of former U.S. President John F. Kennedy crashed into the Atlantic Ocean in an accident that drew attention from all around the world....

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“Treat the Earth well; it was not given to you by your parents, it was loaned to you by your children.” These words were delivered by NOS Assistant Administrator John H. Dunnigan at the 11th Annual Waterkeeper Alliance Conference....

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Algin, an emulsifying and bonding agent, is extracted from kelp and used in these products. Kelp is also used as food on mollusk farms. Between 100,000 and 170,000 wet tons of kelp are harvested from California waters each year.

Kelp forests are extremely biologically productive habitats for a huge range of sea creatures including fish, urchins, sea otters, sea lions, and even some whales. Because of this, kelp forests are critical for fishing and recreation industries.

Sadly, overfishing disrupts the balance of kelp forests by removing predators and allowing plant-eating populations to explode and overeat the kelp, destroying the forests. Pollution, such as sediment runoff and industrial waste, also contributes to the destruction of kelp forests.

Today, many kelp forests are located in marine protected areas and are studied by NOAA scientists. Kelp forests are monitored for kelp size and distribution, physical oceanic conditions, and associated life. The more that we discover about these amazing habitats, the better they can be preserved and strengthened.

For more information:
Ecosystems: Impacts on Kelp Forests, National Marine Sanctuaries
Kelp Forests, Olympic Coast National Marine Sanctuary
Kelp Forest and Rocky Subtidal Habitats, Monterey Bay National Marine Sanctuary

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