Oceans cover nearly three-fourths of our planet's surface, but what goes on under the water is usually out of sight and, often, out of mind. This article brings to the surface changes in the biogeography of the waters off Maine: divemagazine.com/scuba-diving-long-reads/i-dived-the-gulf-of-maine-and-saw-one-fish

When a U.S. submarine ran into an unmapped seamount in the South China Sea two months ago, many wondered how that could happen. It turns out only 19% of the world's sea floor has been mapped. Moreover, the South China Sea is known to have particularly tricky underwater terrain. You can use this mapping tool from the General Bathymetric Chart of the Oceans (GEBCO) to visualize ocean topography: download.gebco.net/ GEBCO is working to produce a complete, publicly available map of the world's oceans by 2030.

Conservationists are trying to safeguard the region of the Arctic Ocean that will be the most likely to persist as frozen ice according to climate models. This Last Ice Area, as it is being called, stretches from northwestern Greenland into the Canadian Arctic Archipelago and may serve as a refuge for organisms that depend on sea ice, from polar bears to fish and crustaceans to microbes. www.sciencenews.org/article/arctic-last-ice-area-climate-change

Stronger-than-usual trade winds are shifting water temperatures in the Pacific Ocean, creating a La Niña effect that is expected to influence weather patterns through the winter and into the spring. Because La Niña impacts vary with the location, check out the maps in this article to see what might be in store for you: www.wsj.com/articles/la-nina-is-coming-to-shape-winter-forecasts-what-to-know-11636666122

Released earlier this month, this animation illustrating comparative ocean depths is worth checking out: www.youtube.com/watch?v=Q5C7sqVe2Vg

Earlier this week researchers announced the completion of the Allen Coral Atlas, the first ever interactive mapping tool of the world's shallow coral reefs. Building on the work of more than 450 research teams and nearly 2 million satellite images, the atlas is named for the late Microsoft co-founder and philanthropist Paul Allen who was an early supporter of the project. allencoralatlas.org/atlas/#6.00/20.1359/-155.5908

Did you know that there are waterfalls underwater?? The largest waterfall in the world is the Denmark Cataract, 2000 feet under the ocean in the Denmark Strait that separates Iceland and Greenland. Cold, dense water flows over the top of an undersea ridge and rapidly sinks two miles to the ocean floor, creating a "downward flow estimated at well over 123 million cubic feet per second," making this the world's largest and highest waterfall by a long shot.  (For comparison, Angel Falls is 0.6 miles tall, and average flow over Victoria Falls is 33 thousand cubic feet per second.)  oceanservice.noaa.gov/facts/largest-waterfall.html

The National Geographic Society has (finally) declared the waters around Antarctica to be the world's fifth ocean.  The Southern Ocean, defined as the waters in the Southern Hemisphere south of 60 degrees latitude which roughly corresponds to the ocean encircled by the Antarctic Circumpolar Current, can now join the other four oceans -- Atlantic, Pacific, Indian, and Arctic -- on the geography bee :-). National Geographic is late to the party: scientists, the U.S. National Oceanic and Atmospheric Administration, and the U.S. Board on Geographic Names (which is responsible for uniform geographic name usage across the federal government) have recognized the Southern Ocean since the 1990s. www.nationalgeographic.com/environment/article/theres-a-new-ocean-now-can-you-name-all-five-southern-ocean

Like the hurricane season in the northern Atlantic Ocean, the cyclone season in the northern Indian Ocean is generally at its most intense from May to November. Over the last week, the cyclone season began with Cyclone Tauktae (Burmese for "gecko"), the biggest storm to hit the north coastal Indian state of Gujarat in more than 20 years. (Moving nearly 200,000 people in low-lying areas to shelters has also raised concerns about the spread of COVID in the coming weeks.)  This satellite image shows Tauktae as it approached Gujarat: c.ndtvimg.com/2021-05/4uaunabc_cyclone-tauktae650_625x300_17_May_21.jpg

This map has been in the news this week as climate scientists are trying to call attention to the impact of cooling waters off Greenland's southeastern coast: www.cbsnews.com/news/climate-change-map-warning/

The Gulf Stream, which carries 30x more water than all the world's rivers combined, has played a pivotal role in shaping climate, biogeography, and human civilization in Europe, North America, Africa, South America, and even Asia. Now, a growing body of scientific research is finding this critical conveyor belt of thermal energy is slowing and weakening. This article from The New York Times walks readers through the science and its implications. www.nytimes.com/interactive/2021/03/02/climate/atlantic-ocean-climate-change.html

A new report finds that the planet is losing 1.2 trillion tons of ice each year, up from 760 billion tons in the 1990s, and the pace of ice loss is accelerating. Scientists used satellite data to study land and sea ice and found the areas experiencing the greatest loss of ice are Greenland and Antarctica, where warming water is eating away at glaciers and ice sheets where they meet the sea. Moreover, the report finds that previous estimates fail "to fully account for the role of ocean undercutting" and sea-level rise from melting ice "may be underestimated by 'at least a factor of 2.'” ... “'It’s like cutting the feet off the glacier rather than melting the whole body,' said Eric Rignot, a study co-author and a glacier researcher at NASA’s Jet Propulsion Laboratory and the University of California at Irvine. 'You melt the feet and the body falls down, as opposed to melting the whole body.'” www.washingtonpost.com/climate-environment/2021/01/25/ice-melt-quickens-greenland-glaciers

Some of the first detailed maps of the seafloor were produced by Marie Tharp, a geologist and cartographer who was barred from ocean-mapping voyages because she was a woman. Instead, she stayed ashore and analyzed the data collected. Her iconic maps -- like this one from 1977 www.sciencenews.org/wp-content/uploads/2021/01/010521_sn100_earth_spotlight-tharp_inline1-1004x580.jpg -- revolutionized the understanding of ocean topography and were instrumental in tipping the scales toward continental drift theory.  (from www.sciencenews.org/article/marie-tharp-maps-plate-tectonics-seafloor-cartography)

As 2020 winds down, the world has a new marine sanctuary, the largest in the Atlantic Ocean and the fourth-largest in the world. Centered around the South Atlantic's remote Tristan da Cunha archipelago, the new marine sanctuary "will protect tens of millions of native and migratory birds, rare migratory sharks, whales, seals, golden undersea forests of kelp, and penguins—collectively valued as a UNESCO World Heritage Site—from illegal mining, fishing, and other extractive activities." www.goodnewsnetwork.org/tristan-da-cunha-biggest-marine-protected-area/

Although not obvious from most maps of Japan, Japan extends most of the way to Taiwan because of the Ryukyu Islands, the archipelago that includes Okinawa and stretches nearly 800 miles south of Japan's four main home islands. Archaeological evidence suggests the Ryukyu Islands were settled more than 30,000 years ago, but recent research mapping ocean currents suggests those early settlers would had to have set out for the Ryukyu Islands intentionally because ocean currents would not have carried drifting boats near the islands. www.sciencenews.org/article/ancient-humans-sea-voyage-japan-ryukyu-island-migration

Today, Alaska's glaciers, the melting of which has already fueled about 30% of global sea level rise, are all that remains of the Cordilleran ice sheet that once covered the northwestern quadrant of North American down into what is today Idaho and Washington. Researchers are now finding, to their surprise, that temperature changes in the North Pacific, rather than the Atlantic, are perhaps a better leading indicator of global climate changes as diverse as a weakening of Asian monsoons, melting in Antarctica, and a drop in salinity in the Atlantic. www.sciencenews.org/article/north-pacific-ice-sheets-climate-change

Earlier this week, The Wall Street Journal ran an article on the first documented trans-Atlantic journey by a mini-sub carrying narcotics -- in this case, 3 tonnes of cocaine worth $100 million -- from South America to Europe. (There likely have been previous journeys not thwarted by first bad weather and then authorities.) This map, from The Wall Street Journal, shows the sub's route, as re-created by Spanish police. (from www.wsj.com/articles/inside-the-first-narco-submarine-caught-after-crossing-the-atlantic-11603033200)

Spring has returned to the Southern Hemisphere. In the Southern Ocean, as in the rest of the world's oceans, illegal fishing accounts for a significant proportion of all fishing activity.  In the Crozet Islands, in the far southern Indian Ocean not far north of the Antarctic Convergence (the point at which cold polar water sinks beneath slightly warmer subantarctic waters, creating a churning of nutrients and a biological and hydrological "moat" encircling Antarctica), researchers fitted albatrosses with radar devices. Because albatrosses are naturally drawn to fishing ships and can spot them from as far as 30 km away, albatrosses carrying radar sensors were used to identify fishing ships that had illegally turned off their automatic identification systems. More than a quarter of the ships albatrosses detected in the waters around the Crozet Islands, which are a French-protected marine sanctuary, had turned off their AIS as had 37% of the albatross-detected fishing ships in nearby international waters. www.popularmechanics.com/science/a30694308/bird-cops-illegal-fishing

NASA is investigating a growing area over the South Atlantic where the earth's magnetic field is mysteriously weakening, already posing a problem for satellites that fly over the region. "On average, the planet's magnetic field has lost almost 10% of its strength over the last two centuries - but there is a large localised region of weakness stretching from Africa to South America. Known as the South Atlantic Anomaly, the field strength in this area has rapidly shrunk over the past 50 years just as the area itself has grown and moved westward." news.sky.com/story/nasa-investigates-mysterious-south-atlantic-anomaly-12051548

On April 1, the U.S. Coast Guard ordered cruise ships in U.S. waters to be sequestered indefinitely to prevent the spread of COVID-19. As of earlier this month, more than 12,000 crew members remain stuck on cruise ships in U.S. waters, most unable to go home because of travel restrictions. According to a report by USA Today, the Coast Guard continues to track "57 cruise ships moored, at anchor, or underway in vicinity of a U.S. port, or with potential to arrive in a U.S. port." www.usatoday.com/story/travel/cruises/2020/08/08/cruise-ships-us-have-12000-crew-members-amid-covid-19/5574288002/

The Indian Ocean island nation of Mauritius, considered part of Africa, usually derives much of its income from tourism, with its pristine beaches and coral reefs being the big draw. For the last six months, though, tourism has plummeted, and now Mauritius faces what may be a more long-lived threat to its tourism: heavy bunker fuel spilling out of a Japanese tanker that ran aground on a reef off Mauritius's east coast and is beginning to break apart. This map shows the tanker's route heading to Brazil from Singapore through the Strait of Malacca and across the Indian Ocean straight into a coral reef: specials-images.forbesimg.com/imageserve/5f32255b76f5a4d456105eb2/960x0.jpg Mauritius has declared a state of emergency, and residents are trying to stop the oil with homemade booms of hair, straw, tights, plastic bottles, and sugar cane leaves. (The map is from a great Forbes article on how satellite technology is being deployed in this situation: www.forbes.com/sites/nishandegnarain/2020/08/09/how-satellites-traced-the-fateful-journey-of-the-ship-that-led-to--mauritius-worst-oil-spill-disaster/#7db02e345b42.)

Oceans also have food deserts: regions where nutrient levels are too low to fuel the growth of phytoplankton or any other life. Consequently, there is very little organic matter to sink through the water column or settle on the seafloor. Researchers studying one of these ocean food deserts -- the abyssal plain 3700 to 5700 meters beneath the South Pacific Gyre -- were surprised to find microbes in the sediment of this food desert, some more than 100 million years old, that began to metabolize and reproduce when supplied with nutrients. www.sciencenews.org/article/ancient-seafloor-microbes-woke-up-after-over-100-million-years

Coral bleaching occurs when unusually warm water temperatures lead to coral polyps' eviction of their symbiotic algae. But some of the world's most spectacular coral reefs are located in the hot, saline waters of the Red Sea and Persian Gulf. Scientists based in the UAE are studying local reef ecology to try to understand how corals and other fauna can withstand the extreme conditions. www.al-monitor.com/pulse/originals/2020/06/united-arab-emirates-coral-reef-fauna-climate-change.html

Vanuatu and the Solomon Islands have been in the news this week, having been hit by a massive late-season Category 5 cyclone. (In the southern hemisphere, the tropical storm season is reversed because the seasons are reversed. In both hemispheres, fall generally brings cooling waters and an end to the tropical storm season.) Lying northeast of Australia, the Republic of Vanuatu and the Solomon Islands are both volcanic archipelagos in the region of the South Pacific between the equator and the Tropic of Capricorn known as Melanesia. upload.wikimedia.org/wikipedia/commons/thumb/5/59/Oceania_UN_Geoscheme_-_Map_of_Melanesia.svg/1920px-Oceania_UN_Geoscheme_-_Map_of_Melanesia.svg.png

Tomorrow is the beginning of daylight savings time in those parts of the United States that adopt daylight savings time. Another time oddity is the International Date Line, the imaginary line that roughly corresponds to a longitude of 180°. The west side of the line is a day ahead of the east side of the line. Although the line jogs around certain political entities, it still creates for some curious situations, especially as far as islands are concerned. In the South Pacific, clocks in Tonga and American Samoa, for example, will show precisely the same time, but Tonga is a day ahead of American Samoa because, even though they share a time zone, Tonga is on the west side of the International Date Line. In the North Pacific, Big Diomede and Little Diomede are two islands that sit 2.5 miles apart in the Bering Strait but are separated by the International Date Line (and geopolitics). Big Diomede, part of Russia, is a day ahead of Little Diomede, which is part of Alaska, leading to their respective nicknames Tomorrow Island and Yesterday Island. static01.nyt.com/images/2012/07/31/opinion/31borderlines/31borderlines-blog427.jpg