Oceanography


Looks healthy, but still lacks the big predatory fish... how would it rate on the Promonitor Index? AF Johnson, CC BY-NC-SA

By Andrew Frederick Johnson, University of California, San Diego

As the Earth warms and glaciers all over the world begin to melt, the natural concern has been how all of that extra water will contribute to sea level rise.

Less considered is what happens to all of the organic carbon found in those glaciers when they melt. A new paper estimates what could happen if major ice sheets break down.

Glaciers and ice sheets contain about 70 percent of the Earth's freshwater and ongoing melting is a major contributor to sea level rise. But, glaciers also store organic carbon derived from both primary production on the glaciers and deposition of materials such as soot or other fossil fuel combustion byproducts.  



Scientists propose a new, potentially more accurate way, to measure the rate of sea level rise. Shutterstock

By Carling Hay, Harvard University

When you ask yourself what the biggest unanswered scientific questions are, “how did sea levels change over the past 100 years?” is unlikely to appear at the top of your list.


After mass bleaching in 1998, more than half of coral reefs in the Seychelles have slowly recovered. Nick Graham

By John Pandolfi, The University of Queensland

Coral reefs are the poster child for the damage people are doing to the world’s oceans. Overfishing, pollution and declining water quality have all taken their toll on reefs around the world. Perhaps the most famous example is Australia’s Great Barrier Reef, where half of the coral cover has disappeared over the past 25 years.

The change in global sea level rise since the beginning of the 20th century has been significantly larger than previous estimates according to new estimates in a new paper.

The paper, co-authored by Carling Hay, a Harvard post-doctoral fellow in the Department of Earth and Planetary Sciences (EPS), and Eric Morrow, a recent PhD graduate, says that previous estimates of global sea-level rise from 1900-1990 had been over-estimated by as much as 30 percent.  

But it confirms previous estimates of sea-level change since 1990, and that suggests that the rate of sea-level change is increasing more quickly than previously believed. 

The massive ice sheet that covers about 80 percent of Greenland is the largest single chunk of melting snow and ice in the world
and for that reason it is considered the biggest potential contributor to rising sea levels due to glacial meltwater in a warming world.

What gets the most media, and therefore a lot of research, attention is the ice sheet's aquamarine lakes -- bodies of meltwater that tend to abruptly drain -- and monster chunks of ice that slide into the ocean to become icebergs.


Ocean Currents in the South Asian Archipelago

The losses of AirAsia QX8501 and Malaysia Airlines MH370 are tragic.  I hope that the relatives may find some comfort in the knowledge that their loved ones will have a lasting monument in improvements in air safety and in improved knowledge of our planet's oceans and climate.

As a direct result of the loss of MH370 a large scale ocean-floor survey was commenced, leading to almost daily discoveries of scientific importance. 

MH370 Operational Search Update—07 January 2015

The ice on Greenland formed due to processes in the deep Earth interior of the Arctic, large-scale glaciations that began about 2.7 million years ago. Prior to that, the northern hemisphere was so warm it was mostly without it, and that period lasted for 500 million years.

The big question geologically is why the glaciation of Greenland only developed so recently. 

It's because of the interaction of three tectonic processes. Greenland literally had to be lifted up, so that the mountain peaks reached into sufficiently cold altitudes of the atmosphere. Greenland also needed to move sufficiently far northward, which led to reduced solar irradiation in winter. Then a shift of the Earth axis caused Greenland to move even further northward.


Over the past decade, ocean acidification has started to receive recognition outside science, though primarily as another weapon in the 'carbon dioxide' culture war on the modern world, similar to methane being discussed this year.

Politics aside, it is a vital area for study and a new article outlines three major challenges to understanding the real issues and effects: It needs to expand from single to multiple drivers, from single species to communities and ecosystems, and from evaluating acclimation to understanding adaptation.  


Oceanlab Scientists Film Supergiant Amphipod and Deepest Fish

Scientists at the University of Aberdeen have set a new record for the world's deepest fish, a species of snailfish, which was filmed in the Mariana Trench this year.

The new finding was just one of several new species discovered, as well as the first footage of a living supergiant amphipod.