Posts Tagged phytoplankton

Apr 6 2016

New NASA Study Shows Lessening El Nino Impacts This Spring

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Seafood News

A new NASA study documents the current El Nino impact on the marine food chain, hoping to show where recovery may begin this spring.  The preliminary conclusions are that a recovery from El Nino is underway and that in Chile and Peru, impacts were less devastating than the 1998 super El Nino.

An El Nino, in which masses of warm tropical water slosh eastward to the coast of South America, has a huge impact on primary marine production, which NASA scientists are currently studying.

El Nino’s mass of warm water puts a lid on the normal currents of cold, deep water that typically rise to the surface along the equator and off the coast of Chile and Peru, said Stephanie Uz, ocean scientist at Goddard Space Flight Center in Greenbelt, Maryland. In a process called upwelling, those cold waters normally bring up the nutrients that feed the tiny organisms, which form the base of the food chain.

“An El Nino basically stops the normal upwelling,” Uz said. “There’s a lot of starvation that happens to the marine food web.” These tiny plants, called phytoplankton, are fish food — without them, fish populations drop, and the fishing industries that many coastal regions depend on can collapse.

NASA satellite data and ocean color software allow scientists to calculate the amount of green chlorophyll — and therefore the amount of phytoplankton present.

The ocean color maps, based on a month’s worth of satellite data, can show that El Nino impact on phytoplankton. In December 2015, at the peak of the current El Nino event, there was more blue — and less green chlorophyll — in the Pacific Ocean off of Peru and Chile, compared to the previous year. Uz and her colleagues are also watching as the El Nino weakens this spring, to see when and where the phytoplankton reappear as the upwelling cold water brings nutrients back to the region.

“They can pop back up pretty quickly, once they have a source of nutrients,” Uz said.

Researchers can also examine the differences in ocean color between two different El Nino events. During the large 1997-1998 El Nino event, the green chlorophyll virtually disappeared from the coast of Chile. This year’s event, while it caused a drop in chlorophyll primarily along the equator, was much less severe for the coastal phytoplankton population. The reason — the warmer-than-normal waters associated with the two El Nino events were centered in different geographical locations. In 1997-1998, the biggest ocean temperature abnormalities were in the eastern Pacific Ocean; this year the focus was in the central ocean. This difference impacts where the phytoplankton can feed on nutrients, and where the fish can feed on phytoplankton.

“When you have an East Pacific El Nino, like 1997-1998, it has a much bigger impact on the fisheries off of South America,” Uz said. But Central Pacific El Nino events, like this year’s, still have an impact on ocean ecosystems, just with a shift in location. Researchers are noting reduced food available along the food chain around the Galapagos Islands, for example. And there has been a drop in phytoplankton off the coast of South America, just not as dramatically as before.

Scientists have more tools on hand to study this El Nino, and can study more elements of the event, Uz said. They’re putting these tools to use to ask questions not just about ocean ecology, but about the carbon cycle as well.

“We know how important phytoplankton are for the marine food web, and we’re trying to understand their role as a carbon pump,” Uz said. The carbon pump refers to one of the ways the Earth system removes carbon dioxide from the atmosphere. When phytoplankton die, their carbon-based bodies sink to the ocean floor, where they can remain for millions of years. El Nino is a naturally occurring disruption to the typical ocean currents, she said — so it’s important to understand the phenomenon to better attribute what occurs naturally, and what occurs due to human-caused disruptions to the system.

Other scientists at Goddard are investigating ways to forecast the ebbs and flows of nutrients using the center’s supercomputers, incorporating data like winds, sea surface temperatures, air pressures and more.

“It’s like weather forecasts, but for bionutrients and phytoplankton in the ocean,” said Cecile Rousseaux, an ocean modeler with Goddard’s Global Modeling and Assimilation Office. The forecasts could help fisheries managers estimate how good the catch could be in a particular year, she said, since fish populations depend on phytoplankton populations. The 1997-1998 El Nino led to a major collapse in the anchovy fishery off of Chile, which caused economic hardships for fishermen along the coast.

So far, Rousseaux said, the phytoplankton forecast models haven’t shown any collapses for the 2015-2016 El Nino, possibly because the warm water isn’t reaching as far east in the Pacific this time around. The forecast of phytoplankton populations effort is a relatively new effort, she said, so it’s too soon to make definite forecasts. But the data so far, from the modeling group and others, show conditions returning to a more normal state this spring.

The next step for the model, she said, is to try to determine which individual species of phytoplankton will bloom where, based on nutrient amounts, temperatures and other factors — using satellites and other tools to determine which kind of microscopic plant is where.

“We rely on satellite data, but this will go one step further and give us even more information,” Rousseaux said.

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Jul 22 2015

Monterey Bay’s latest trick: turning turquoise

The water in the Monterey Bay, including off Marina State Beach, has been a turquoise color in the past few days because of the presence of coccolithophores, a single-celled phytoplankton that develops scales that reflect the sun. (Vern Fisher – Monterey Herald)

Monterey >> Our corner of the sea is turning a brighter shade of blue.

An odd and little-understood ocean phenomenon is taking place on Monterey Bay right now, and you may have noticed it: the waters are turning an almost tropical turquoise color. Derived from an abundance of a harmless microorganism, the colorful blooms are usually found in the open sea.

But Monterey Bay’s is the second bloom along the California coast in a month. It is due to the presence of coccolithophores, a single-celled phytoplankton that develops hubcap-shaped limestone scales that reflect the sun, turning the water pastel colored.

“The optics of the water when one gets coccolithophores blooms, it looks like this,” said Debora Iglesias-Rodriguez, a biological oceanographer with UC Santa Barbara, noting how odd it is to see a bloom along the shore. “This is really unusual.”

The organisms shed their scales in the water, with the phenomenon usually occurring in northern seas. When you have billions of them, they can impact huge stretches of the open sea, a visual that can be bizarre and stunning in its intensity.

“The blooms are so bright you have to wear sunglasses,” Iglesias-Rodriguez said.

In fact, coccolithophores are responsible for something most people are familiar with: the White Cliffs of Dover, along the English Channel. The striking white cliff faces were created from sediment filled with the organism’s discarded scales.

The first bloom showed up last month in the Santa Barbara Channel. Iglesias-Rodriguez said she is researching why it happened there, including whether the recent oil spill is a factor.

But late last week, it started showing up in Monterey Bay. Satellite data shows the waters from Point Pinos in the south to Natural Bridges State Beach in the north colored a vibrant hue.

Iglesias-Rodriguez is in touch with colleagues at the Monterey Bay Aquarium Research Institute in the hopes of comparing water samples. She said she can only find one unofficial record of the phenomenon occurring off Santa Barbara, dating to the 1990s.

“We are trying to figure out: Why now?” she said.

Coccolithophores seem to thrive when other phytoplankton cannot, particularly when marine phosphorous levels are low. They typically bloom in early summer.

“This would be the right time for them,” Iglesias-Rodriguez said.

This image from Saturday was created using data from NASA’s AQUA satellite, with help from biological oceanographer John Ryan at the Monterey Bay Aquarium Research Institute. The turquoise water is created by the presence of a microorganism. (Courtesy MBARI)

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