Lakes and oceans appear blue for several reasons. One is that the surface of the water reflects the color of the sky.
When materials absorb light, the light's energy is transferred to the material, often as heat. Some of the light hitting the surface is reflected back directly but most of it penetrates the surface, interacting with its molecules. The water molecule can vibrate in three different modes when light hits it. The red, orange, yellow, and green wavelengths of light are absorbed and the remaining light we see is composed of the shorter wavelength blues and violets. This is the main reason why the ocean is blue.
Text via Wikipedia
Algae or "seaweeds" (left) differ from seagrasses (right) in several ways. Algae on the seafloor have a holdfast and transport nutrients through the body by diffusion, while seagrasses are flowering vascular plants with roots and an internal transport system.
[Credit: Courtesy of the Integration and Application Network (ian.umces.edu), University of Maryland Center for Environmental Science]
"The whale shark (Rhincodon typus) is an amazing animal, the biggest fish in the sea, yet scientists still know very little about its life and habits. Find out what we do know about this amazing and docile animal in this infographic – and learn why it’s threatened and how we can all take part in the solution."
"Found throughout the tropic and temperate ocean, mobuild rays, as manta and devil rays are collectively known, are being overfished. Growing demand for gill rakers -- feathery structures these filter feeders use to strain food as they glide through water -- puts these species at great risk of depletion around the world."
"Ocean conservation is essential but sometimes difficult to understand. Pew joined forces with cartoonist Jim Toomey, the artist behind 'Sherman’s Lagoon,' on 10 animated videos that explain the complicated concepts that guide efforts to protect our oceans."
"This 30 minute video lists the diverse types of lifeforms in the sea, and how the threats to ocean biodiversity differ from threats on the land."
"This 30 minute video examines how coral reefs are threatened by global warming, and how they could be saved."
SeaWorld announced it was ending its orca breeding programme and said the 29 orcas currently in its parks would be the last. But the company did not step back from its long-held claim that its orcas - also known as killer whales - live long healthy lives. Liz Bonnin was granted unique access to SeaWorld to investigate this claim and weigh the scientific evidence...
"When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white."
"Vertical ecological zones in the deep ocean as organized by ocean depth below the surface and seawater temperature."
"Subscribe to the Catlin Seaview Survey here:
The Catlin Seaview Survey will be taking thousands of 360 degree panoramas of the Great Barrier Reef, not just for science, but so that every person with an internet connection can experience the world's largest structure...at least virtually.
The partnership with Google will bring these images into Google Maps, Google Earth, Panoramio and, of course, YouTube."
Via SciShow: "Plastic is a huge problem in the oceans, but engineers and research groups are working on how to deal with it. Hank describes some of the leading proposed solutions."
"How is it possible for air-breathing marine mammals like sperm whales and elephant seals to hold their breath for so long?"
"The great white is one of six shark species that are endothermic, which means they can raise internal body temperatures over that of surrounding waters. This allows great whites to inhabit extreme depths as well as cold waters of higher latitudes, while still being able to function efficiently to capture swift and agile prey."
[via National Geographic]
A short video all about a group of often overlooked eight-plated molluscs living in the waters of British Columbia, Canada.
"Phytoplankton are the base of the marine food web and are crucial players in the Earth's carbon cycle. They are also incredibly diverse. This visualization shows dominant phytoplankton types from 1994-1998 generated by the Darwin Project using a high-resolution ocean and ecosystem model. The model contains flow fields from 1994-1999 (generated by the ECCO2 model), inorganic nutrients, 78 species of phytoplankton, zooplankton, as well as particulate and dissolved organic matter. Colors represent the most dominant type of phytoplankton at a given location based on their size and ability to uptake nutrients. Red represents diatoms (big phytoplankton, which need silica), yellow represents flagellates (other big phytoplankton), green represents prochlorococcus (small phytoplankton that cannot use nitrate), and cyan represents synechococcus (other small phytoplankton). Opacity indicates concentration of the phytoplankton as carbon biomass."
via NOAA Science on a Sphere http://sos.noaa.gov/Datasets/dataset.php?id=630
"This Great White Shark track dataset for SOS and SOS Explorer shows the path of Nicole the shark, who swam 7,000 miles from South Africa to Australia in only 99 days!"
"in November of 2003, about 30 great white sharks were tagged off of the coast of South Africa. Most of the sharks stayed near Africa, but one of these sharks really surprised researchers when it traveled all the way to Australia. This journey of 11,100 km (6,897 miles) took the shark only ninety-nine days. This is considered to the farthest known distance traveled by a shark. The shark's tag detached when the shark was just south of Exmouth Gulf in Western Australia. Less than nine months later, scientists were truly surprised to find the same shark back in waters near South Africa. Using identification techniques with the dorsal fin, scientists were able to confirm that this shark was the same one that had traveled to Australia in the previous months. The total round trip from Africa to Australia and back is 20,000 km (12,400 miles), which is by far, the farthest known trip taken by a shark. This dataset follows the shark from South Africa to Australia."
via NOAA Science on a Sphere http://sos.noaa.gov/Datasets/dataset.php?id=180