The loss of phytoplankton

Phytoplankton rapidly disappearing from the Indian Ocean

Loss of mini marine plants at base of food web threatens sea’s ecology

BY THOMAS SUMNER 

WATER COLOR  Oxygen-producing plankton are on the decline in the western Indian Ocean, new research suggests. The work tracked changes in water color across the ocean caused by the presence — or absence — of phytoplankton, such as that seen in this swirling 2013 phytoplankton bloom.LANCE/NASA

ScienceNews,

1 February, 2016

A rapid loss of phytoplankton threatens to turn the western Indian Ocean into an “ecological desert,” a new study warns. The research reveals that phytoplankton populations in the region fell an alarming 30 percent over the last 16 years.

A decline in ocean mixing due to warming surface waters is to blame for that phytoplankton plummet, researchers propose online January 19 in Geophysical Research Letters. The mixing of the ocean’s layers ferries phytoplankton nutrients from the ocean’s dark depths up into the sunlit layers that the mini plants inhabit.

The loss of these microbes, which form the foundation of the ocean food web, may undermine the region’s ecosystem, warns study coauthor Raghu Murtugudde, an oceanographer at the University of Maryland in College Park.

“If you reduce the bottom of the food chain, it’s going to cascade,” Murtugudde says. The phytoplankton decline may be partially responsible for a 50 to 90 percent decline in tuna catch rates over the last half-century in the Indian Ocean, he says. “This is a wake-up call to look if similar things are happening elsewhere.”

In the 20th century, surface temperatures in the Indian Ocean rose about 50 percent more than the global average. Previous investigations into this ocean warming’s impact on phytoplankton suggested that populations had increased. But those studies looked at only a few years of data — not long enough to clearly identify any long-term trend.

Roxy Mathew Koll, a climate scientist at the Indian Institute of Tropical Meteorology in Pune, Murtugudde and colleagues tracked the microscopic phytoplankton from space. Phytoplankton, like land plants, are tinted green. When the sea surface is filled with phytoplankton, the water takes on a lighter, greener tinge. As the phytoplankton population thins, the water turns darker and bluer.

Analyzing satellite images of ocean color collected over the last 16 years, the researchers found a 30 percent drop in the abundance of green-tinted microbes per cubic meter of water. Combining this data with computer simulations of the Indian Ocean, the researchers reconstructed the ups and downs of phytoplankton in the region over the last six decades. That work suggests that phytoplankton populations in the western Indian Ocean have declined 20 percent relative to 1950.

Warming surface temperatures resulted in the long-term drop in phytoplankton, the ocean simulations revealed. To survive, phytoplankton rely on nitrates produced by bacteria that dwell around 100 to 500 meters below the sea surface. Those nitrates are churned upward by such forces as winds blowing over the ocean surface. Warmer water is less dense and stays near the surface. As the sea surface becomes warmer relative to the deeper ocean due to climate change, the two layers become harder to mix and nutrients become scarcer in the sunlit top layer.

Upcoming ship-based studies should verify the new results, says Michael McPhaden, a physical oceanographer at the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory in Seattle. Piracy off the coast of Somalia had up until recently prevented research vessels from studying parts of the western Indian Ocean, but this year marks the beginning of a five-year Indian Ocean expedition.

“This work includes logical leaps that are sensible to make based on what we know about how the system works, but you always want to go out and verify,” McPhaden says.

Phytoplankton Population Drops 40 Percent Since 1950

Researchers find trouble among phytoplankton, the base of the food chain, which has implications for the marine food web and the world's carbon cycle

The microscopic plants that form the foundation of the ocean's food web are declining, reports a study published July 29 in Nature.

The tiny organisms, known as phytoplankton, also gobble up carbon dioxide to produce half the world's oxygen output—equaling that of trees and plants on land.

But their numbers have dwindled since the dawn of the 20th century, with unknown consequences for ocean ecosystems and the planet's carbon cycle

Climate change headlines - 05/21/2015

The Dying Earth - 05/21/2015

The main headlines come out of the Antarctica with an unexpected and unprecedented collapse of the ice sheet and loss of ice. The bad news just keeps coming, and coming

Sudden onset of ice loss in Antarctica so large it affects Earth's gravity field

A group of scientists, led by a team from the University of Bristol, UK has observed a sudden increase of ice loss in a previously stable region of Antarctica. 

The research is published today in Science.

Using measurements of the elevation of the Antarctic ice sheet made by a suite of satellites, the researchers found that the Southern Antarctic Peninsula showed no signs of change up to 2009. Around 2009, multiple glaciers along a vast coastal expanse, measuring some 750km in length, suddenly started to shed ice into the ocean at a nearly constant rate of 60 cubic km, or about 55 trillion litres of water, each year.

'Stable' Antarctic ice sheet may have started collapsing, scientists say

A vast slab of Antarctic ice that was previously stable may have started to collapse, according to new analysis of satellite data.

Research published in the journal Science on Thursday found the Southern Antarctic Peninsula (SAP) ice sheet is losing ice into the ocean at a rate of 56 gigatons each year – about 8,500 times the mass of the Great Pyramid of Giza. 

This adds around 0.16mm per year to the global sea level.

Glaciers in part of Antarctic thought to be stable suddenly melting at a massive rate, say scientists

A sudden and massive melting of glaciers in a part of the Antarctic that was thought to be relatively stable has been detected by satellites monitoring the polar ice sheet, scientists have said.

Many glaciers in the Southern Antarctic Peninsula have become unstable since 2009, releasing vast amounts of ice into the sea equivalent to about 56bn tonnes of meltwater each year, the researchers said.

Multiple glaciers along a stretch of coastline 750km long have suddenly and consistently started to shed ice into the ocean at a constant rate of 60 cubic km or 55 trillion litres of water each year, they report in the journal Science.

Meanwhile in the past few days a major blob of warm water has been discovered in the Indian Ocean that has the potential to migrate up to the North Atlantic and affect the melting of Arctic sea ice.

Everything is connected

Bad News Keeps Flowing From Antarctica

"Lee said it’s likely to continue globe trotting along the ocean conveyor belt and find its way to the Atlantic in the coming decades."

“If this warm blob of water in upper Indian Ocean is transported all the way to North Atlantic, that could affect the melting of Arctic sea ice,” Lee said. “That can also increase hurricane activity and influence the effects of drought in the U.S. These are simply hypotheses that need to be tested and studied in the future work.”

There's the kicker.

Heat is Piling Up in the Depths of the Indian Ocean

The world’s oceans are playing a game of hot potato with the excess heat trapped by greenhouse gas emissions.

Scientists have zeroed in on the tropical Pacific as a major player in taking up that heat. But while it might have held that heat for a bit, new research shows that the Pacific has passed the potato to the Indian Ocean, which has seen an unprecedented rise in heat content over the past decade.

"Temperatures have increased more than two degrees Celsius since the fall of 2013"

"A conference at California’s Scripps Institution of Oceanography earlier this month featured scientists in fields ranging from avian biology to Arctic climatology. They tried to determine the potential impacts of a giant mass of warm, ocean water that currently stretches from the Gulf of Alaska down to Baja California"

The Blob expands from Gulf of Alaska to Baja California

Scientists are watching for how a warmer North Pacific Ocean could affect weather and climate this year. There could also be significant impacts to marine life, including species that form the basis for Alaska’s commercial fisheries.

A conference at California’s Scripps Institution of Oceanography earlier this month featured scientists in fields ranging from avian biology to Arctic climatology. They tried to determine the potential impacts of a giant mass of warm, ocean water that currently stretches from the Gulf of Alaska down to Baja California.

Temperatures have increased more than two degrees Celsius since the fall of 2013.

Meanwhile Arctic sea ice is at a historic low.

Arctic Sea Ice At Historic Low

On May 20, 2015, Arctic sea ice extent was only 12.425 million square km, a record low for the time of the year since satellite measurements began in 1979.

And in the area of extreme weather trends in North America....

May’s torrential rainstorms super-charged by strengthening climate patterns

The month of May is typically known for its severe weather season in the Plains states — tornadoes, damaging winds and very large hail. But this year, May might be remembered more for its prolific rain and flooding — a series of brief but destructive events spurred by an intensifying El Niño in the Pacific Ocean and just part of the upward trend in extreme rainfall events in a warming world.

Drought urgency hits rain country: Washington governor declares state emergency

Washington Gov. Jay Inslee declared a statewide drought Friday — citing historically low snowpack, dwindling rivers and rising temperatures that have plunged nearly the entire West Coast into official emergency status.



“The drought has deepened dramatically over the past few weeks,” said Inslee, a Democrat. “It has spread quickly and now encompasses all of the state of Washington. We are already seeing severe impacts in several areas of the state, and conditions are expected to worsen over time.”

But in a climatic quirk peculiar to the Pacific Northwest this year, Washington's deepening drought is accompanied by regular rainfall, and the major population centers of Seattle, Tacoma, Everett and Spokane are not expected to notice that disaster lurks.

Fairbanks, Alaska, to Start Weekend Warmer Than Phoenix

Mother Nature seems to have the weather flipped upside down with Fairbanks, Alaska, set to start the Memorial Day holiday weekend on a warmer note than Phoenix.

The unusual weather will stem from a dip in the jet stream ushering cool air across Arizona, while a ridge of high pressure continues to allow temperatures to soar throughout eastern Alaska.

As a result, a high in the lower 80s is expected in Phoenix on Saturday as temperatures in Fairbanks climb into the upper 80s.

Climate change: Americans crowding into future heatwave zones, study says

Houston-Dallas-San Antonio and Atlanta-Charlotte-Raleigh areas most affected by ‘double whammy’ of population shift and temperature rises, scientists argue

How climate change is making California's epic drought worse

The Significance of El Niño and Its Impacts

This event shows the significance of El Niño through observations—satellite, in situ, and model simulations—its physical mechanisms and associated biological and biogeochemical impacts, with a focus on the Equatorial Pacific and South America. The event provides a detailed discussion on seasonal ENSO forecasts and will bridge together knowledge from other domestic and international agencies to provide a complete understanding of ENSO.

And here are some scientific presentations -on el-Nino and Antarctic glaciers

Observing Antarctic Glaciers - Eric Rignot