Monday, November 23, 2015

First Glimpse of the 2015 El Niño from in the trenches



If anyone asked me prior to this trip what I expected to find in the Galapagos during this strong El Niño event-- an event that may be on par with the strongest events in the historical record (in 1982-83 and 1997-98)-- I likely would have given a textbook answer of what happens in the Galapagos during a “classic” strong El Niño event.  It would have sounded a bit like this: rain, lots of rain; warn waters; dead sea life; dry, barren landscapes transformed to lush green wonderlands full of fat, happy finches.
Photo by Stephan Hlohowskyj
This picture I had painted in my head came not just from research on El Niño, but also from personal accounts of colleagues who were in the Galapagos during the huge 1982-83 El Niño, which hit the Galapagos very hard.  I heard stories of sea lions dying on the beaches while land birds thrived off of the unusually lush landscape.   Local divers and reef experts also paint a stark picture of the coral reefs, which succumbed to coral bleaching and death as a result of the high ocean temperatures.  Even 30 years after this event, its devastating impact was impossible to ignore while collecting coral samples on our last 2 expeditions.  We were hard pressed to find any large coral heads that survived that event, and all of the corals we sampled had a distinct death band in 82/83.

During these large, classic El Niño events, marine ecosystems crash around the Galapagos and throughout the eastern Pacific Ocean as a result of above average temperatures and a reduced influx of key nutrients from deeper waters.  At the same time, terrestrial ecosystems thrive under above normal rainfall.
The day before we departed for our trip, the Ecuadorian Government declared a “state of emergency due to the phenomenon of El Niño.”  The announcement said that the Ecuadorian Government was forecasting a stronger than normal event with unusually high volume of rainfall, and encouraged residents and visitors to visit their new website to learn about El Niño and its effects on Ecuador.
As an early career scientist who has focused her research largely on the phenomenon of El Niño—aiming to improve our understanding of how the strength and frequency of these events has changed in the past and may change in the future—I was extremely excited to get on the ground to see and measure these impacts in real time. 
So you can imagine my disappointment when I got here to find that the El Niño picture I had painted in my mind was, well only a fairy tale?!  Well, no, but where was all of the rain??
The clouds had definitely rolled in, with ominous clouds above us as we quickly devoured the coveted “encocado de pescado” at Williams, our favorite restaurant on the island.



And the view out of the back porch of our dorms at the Charles Darwin Research Station is no doubt more cloudy every day 



than it was during our last trip in January of 2015 (around the peak of last year’s warm/wet season)






But despite the ominous clouds, it has not rained.  Our boat captain Lenin tells us it rained a few days ago, but made a point of saying that he is skeptical of this El Niño.  He doesn’t believe the hype, and thinks the government’s state of emergency is just a control tactic. 
BUT, on the other hand he notes that the guides have told him that Darwin and Wolf (the most northern Galapagos Islands) are very lush and have been receiving a lot of rain.  So are the northern islands being impacted more by this event so far, despite warm ocean temperatures throughout the islands? This surprising observation has my head reeling through open questions and implications. 

How patchy are the El Niño rains among the islands?   And as a result of this patchiness, could such a large event be missed if only sampled from one island?  What are the implications of this for the interpretation of the frequency of El Niño events in the past from natural archives of past climate (e.g. sediments accumulating at the bottom of Galapagos lakes)? 
I anxiously await our field expedition to Genovesa and Bainbridge crater lakes to try to address these open questions.  We have been monitoring the local climate and lake conditions at these sites to determine how such El Niño events are recorded in these lakes; for example, how much rain falls during El Niño events, and how does this change the conditions of the lake and the sediments deposited on the lake bottom? 

Based on the occurrence of these signature El Niño layers in sediment cores extracted from these lakes, we can then produce improved records of the frequency of El Niño events over the past 6,000+ years.
And now as I finish writing this, it just started raining!!! Stay tuned…to be continued…


This material is based upon work supported by the National Science Foundation under Grant Number (NSF AGS-1561121). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

No comments:

Post a Comment