Since spring, El Niño conditions in the equatorial Pacific have been strengthening. The magnitude of the 2015 El Niño is similar to events in 1997–98 and 1982–83, say scientists, which are the two strongest events in the modern scientific record.
Although this El Niño hasn’t yet reached its peak, the marine food web is starting to feel the loss of phytoplankton – the foundation of the aquatic food chain. This loss is evident in declining concentrations of sea surface chlorophyll, the green pigment that indicates the presence of phytoplankton.
The globes below, derived from satellite data, compare sea surface chlorophyll in the Pacific Ocean in October 2014 and 2015. Shades of green indicate more chlorophyll and blooming phytoplankton. Shades of blue indicate less chlorophyll and less phytoplankton.
October 2014. Image credit: NASA
October 2015. Image credit: NASA
According to NASA, here’s what’s happening:
Trade winds have weakened in the Eastern Pacific, disrupting the normal ocean circulation pattern and allowing the Western Pacific warm pool to propagate eastward.
Below the ocean’s surface, that warm pool is deepening the thermocline —the level that separates warmer surface waters from cooler deep ocean waters — in the east. The deeper pool of warm water has curtailed the usual upwelling of deep water nutrients to the surface of the Eastern Pacific.
Historic observations from the area have shown that with less phytoplankton available, fish that feed upon plankton, as well the bigger fish that feed on them, have a greatly reduced food supply. In past El Niños of this magnitude, the decline in fish stocks has led to famine and dramatic population declines for many marine animals — including Galapagos penguins, marine iguanas, sea lions and seals.
Climate models predict this El Niño will peak around December and weaken during northern hemisphere spring (March–May 2016).
The last time such a strong El Niño occurred (1997–98), there were large population declines throughout the Eastern Pacific marine food web. A strong La Niña then followed in 1998–99 and had the opposite impact: stronger east-to-west trade winds increased upwelling nutrients and fertilized one of the biggest phytoplankton blooms in the satellite record. This brought a dramatic increase in fish populations.
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Bottom line: Globes created from satellite data compare conditions in October 2015 to conditions in October 2014. Data suggest that although 2015’s El Niño hasn’t yet reached its peak, the marine food web is starting to feel the loss of phytoplankton. This loss is evident in declining concentrations of sea surface chlorophyll, the green pigment that indicates the presence of phytoplankton.
Read more from NASA’s Earth Observatory
from EarthSky http://ift.tt/1Ry28Z0
Since spring, El Niño conditions in the equatorial Pacific have been strengthening. The magnitude of the 2015 El Niño is similar to events in 1997–98 and 1982–83, say scientists, which are the two strongest events in the modern scientific record.
Although this El Niño hasn’t yet reached its peak, the marine food web is starting to feel the loss of phytoplankton – the foundation of the aquatic food chain. This loss is evident in declining concentrations of sea surface chlorophyll, the green pigment that indicates the presence of phytoplankton.
The globes below, derived from satellite data, compare sea surface chlorophyll in the Pacific Ocean in October 2014 and 2015. Shades of green indicate more chlorophyll and blooming phytoplankton. Shades of blue indicate less chlorophyll and less phytoplankton.
October 2014. Image credit: NASA
October 2015. Image credit: NASA
According to NASA, here’s what’s happening:
Trade winds have weakened in the Eastern Pacific, disrupting the normal ocean circulation pattern and allowing the Western Pacific warm pool to propagate eastward.
Below the ocean’s surface, that warm pool is deepening the thermocline —the level that separates warmer surface waters from cooler deep ocean waters — in the east. The deeper pool of warm water has curtailed the usual upwelling of deep water nutrients to the surface of the Eastern Pacific.
Historic observations from the area have shown that with less phytoplankton available, fish that feed upon plankton, as well the bigger fish that feed on them, have a greatly reduced food supply. In past El Niños of this magnitude, the decline in fish stocks has led to famine and dramatic population declines for many marine animals — including Galapagos penguins, marine iguanas, sea lions and seals.
Climate models predict this El Niño will peak around December and weaken during northern hemisphere spring (March–May 2016).
The last time such a strong El Niño occurred (1997–98), there were large population declines throughout the Eastern Pacific marine food web. A strong La Niña then followed in 1998–99 and had the opposite impact: stronger east-to-west trade winds increased upwelling nutrients and fertilized one of the biggest phytoplankton blooms in the satellite record. This brought a dramatic increase in fish populations.
Enjoying EarthSky? Sign up for our free daily newsletter today!
Bottom line: Globes created from satellite data compare conditions in October 2015 to conditions in October 2014. Data suggest that although 2015’s El Niño hasn’t yet reached its peak, the marine food web is starting to feel the loss of phytoplankton. This loss is evident in declining concentrations of sea surface chlorophyll, the green pigment that indicates the presence of phytoplankton.
Read more from NASA’s Earth Observatory
from EarthSky http://ift.tt/1Ry28Z0
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