Oceanography

Twice in recent history, the periodic El Niño event has caused sea level drops abruptly in the tropical western Pacific. The tides remain below normal for up to a year in the South Pacific, especially around Samoa, and Samoans call the resulting wet stench of coral die-offs arising from the low sea levels "taimasa" (pronounced [kai' ma'sa]).

A team of scientists at the International Pacific Research Center, University of Hawai'i at Mānoa and at the University of New South Wales, Australia is studying the climate effects of this particular variation of El Niño.  


Satellite observations of global sea-surface temperature have shown that a 30-year upward trend slowed in the last 15 years.  It can't be due to successful mitigation, since outside the United States and a few countries in Europe, CO2 emissions have not dropped back to those levels.

Some satellites carry instruments that provide a global view of the surface temperature of oceans and seas. Satellite and local readings show that sea-surface temperature rose rapidly during the 1970s and '80s but then significantly slowed in the last 15 years.

 Mesopelagic fishes like lantern fishes (Myctophidae) and cyclothonids (Gonostomatidae) live in the twilight zone of the ocean, between 200 and 1,000 meters deep.

 With a stock estimated at 1,000 million tons so far, mesopelagic fish dominate the total biomass of fish in the ocean and are the most numerous vertebrates of the biosphere. Now it turns out they have been severely underestimated. Researchers writing in Nature Communications have estimated their numbers are 10 times higher than previous estimated, based on acoustic observations conducted during the circumnavigation of the Malaspina Expedition.


It's cold and snowy just about everywhere except where you expect it. Ice in northern Alaska’s lakes during winter months is on the decline, as shown by twenty years of satellite radar imagery demonstrating how changes in our climate are affecting high-latitude environments - at least in the last few decades. 

Changes in air temperature and winter precipitation over the last five decades have affected the timing, duration and thickness of the ice cover on lakes in the Arctic. In this region, warmer climate conditions result in thinner ice cover on shallow lakes and, consequently, a smaller fraction of lakes freezing all the way through during winter months. 

Are they landing marks for aliens? Craters from World War II bombs?

The first pictures, which appeared in 2008 after being taken by a tourist, showed some strange circular formations in the shallow waters off the famous white cliffs of chalk on the island Møn in Denmark. And then they disappeared.

In 2011, the circles came back, and this time there were so many that they made it into media stories.
Since those first images appeared, people have searched for an explanation. 


A group of researchers say they have established a new biomarker for how stressed polar bears are about climate change.    

Last year, a team reported that fluctuations in climate and ice cover are closely related to stress among polar bears in East Greenland as indicated by levels of the stress hormone cortisol in hair samples. The team is hopeful this type of analysis will be beneficial once others learn that it can now be done with much greater reliability.


Near the center of Antarctica, measurements from CryoSat - which exists to make comprehensive measurements of the polar regions in an unusually high-inclination orbit and latitudes of 88° north and south -  have detected an unusual pattern in the ice sheet’s elevation. 

CryoSat carries a radar altimeter that can ‘see’ through clouds and in the dark, providing continuous measurements over areas like central Antarctica that are prone to bad weather and long periods of darkness.  The radar measures the surface height variation of ice by timing the interval between the transmission and reception of very short radar pulses as the satellite orbits Earth. CryoSat collects data over Antarctica while passing on northbound and southbound orbits.

Marine cyanobacteria are tiny ocean plants that produce oxygen and make organic carbon using sunlight and CO2, and so they are primary engines of Earth's biogeochemical and nutrient cycles.

They nourish other organisms through the provision of oxygen and with their own body mass, which forms the base of the ocean food chain. Researchers have discovered a new benefit of these tiny cells: Cyanobacteria continually produce and release vesicles, spherical packages containing carbon and other nutrients that can serve as food parcels for marine organisms. The vesicles also contain DNA, likely providing a means of gene transfer within and among communities of similar bacteria, and they may even act as decoys for deflecting viruses.


Pine Island Glacier is one of the biggest routes for ice to flow from Antarctica into the sea and the floating ice shelf at the glacier's tip has been melting and thinning for the past four decades, causing the glacier to speed up and discharge more ice.

It's been a key factor in estimates for sea level rise in a warming world but it turns out that the ice shelf melting depends on the local wind direction, which is tied to tropical changes associated with El Nino.


An international team of scientists predicts that seafloor dwelling marine life will decline by up to 38 percent in the North Atlantic and over five percent globally over the next century, due to global warming. The changes will be driven by a reduction in the plants and animals that live at the surface of the oceans that feed deep-sea communities. As a result, ecosystem services such as fishing will be threatened.