When Marine Productivity Increases, Tree Growth Slows

Written by on November 19, 2014 in Marine Life

Variability in Earth’s climate has opposite effects on marine life and tree growth: the same factors that support marine productivity can result in slower tree growth.

Blue oak in California. Photo credit: <a href="https://www.flickr.com/photos/john_d_rusk/13205180465/">John Rusk</a> via <a href="http://photopin.com">photopin</a> <a href="http://creativecommons.org/licenses/by-nc-sa/2.0/">cc</a>.

Blue oak in California. Photo credit: John Rusk via photopin cc.

New research reveals that the “climatic drivers” that increase upwelling of nutrient-rich water can result in decreased precipitation on land, which leads to slower tree growth. By studying tree rings dating back 600 years, researchers determined that growth patterns in blue oak trees growing near the California coast are highly sensitive to the same climate factors that enhance upwelling.

Upwelling, the process by which deep, cold, nutrient-rich waters rise to the surface, supports marine productivity by fueling blooms of phytoplankton, which form the base of the marine food web. During these 600 years, four of the 10 most “extremely poor” upwelling years occurred since 1950, and seven of the 10 have occurred since 1850.

To investigate the relationship between upwelling and productivity, researchers studied how quickly fish grew every year since the 1940s, the timing of seabird egg laying and fledging success since the 1970s. They found an “exceptionally high” correlation between climate and both marine and terrestrial productivity.

This is because the high pressure systems that support upwelling actually block storm fronts, preventing precipitation from falling on land and leading to slower tree growth. The opposite is true for marine productivity: weak upwelling years are associated with slower fish growth and lower reproductive success for seabirds.

“So in effect we see opposite effects of the same climatic conditions when we look at marine organisms or trees growing nearby on the land,” study co-author David Frank of the Swiss Federal Research Institute WSL said in a news release. “We see how interconnected and complex the earth’s climate system is, especially when we are trying to understand interactions and feedbacks with biological systems.”

“Our study underscores the fact that California is a place of high coastal upwelling variability”, said lead author Bryan Black at the University of Texas at Austin’s Marine Science Institute. “You have to keep that in mind if you’re managing a fishery — for example, you can’t plan for every year being moderate or reliable. There are a lot of ups and downs.”

California coastline.

California coastline. Photo credit: NOAA.

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Copyright © 2014 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of MarineScienceToday.com. She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .

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