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COMPARING BACTERIAL ABUNDANCE IN THE CALIFORNIA CURRENT ECOSYSTEM REGION ACROSS EL NIÑO, BLOB, AND NORMAL YEARS (E)

Evidence suggests surface ocean waters are warming, leading to greater stratification, likely altering marine food webs. To examine the response of microbial communities to changes in upper ocean stratification, we compared bacterial abundance, size, and productivity across three climatic periods with substantially different surface temperature characteristics. We compared data from California Current Ecosystem Long Term Ecological Research cruises that sampled two normal years (2006, 2007) to data from two anomalously warm periods, the Blob in 2014 and the 2016 positive ENSO anomaly (El Niño). While the Blob had warm waters confined near the surface, warming extended deeper during El Niño. Overall, the range in bacterial abundance in warm years, with lowest surface ocean values near 5.0x108 cells L-1 and highest values near 3.1x109 cells L-1, encompassed values observed in normal years. However, regional differences between normal and El Niño data were observed, but anomalies were not always in the same direction. The Blob had comparable regional abundance to normal years. El Niño bacterial abundance data correlated with organic matter concentrations, importantly with particulate organic carbon, providing insight into the carbon reservoirs potentially driving the observed differences. Cell sizing data for warm years also show a different trend, the significance of which is being confirmed. Bacterial productivity measurements and 16S-based characterization of the active microbial community are currently being analyzed to further elucidate microbial dynamics in the region.

Authors

Rivera, S. R., Scripps Institution of Oceanography, UC San Diego, USA, s6rivera@ucsd.edu

Rasina, B., Scripps Institution of Oceanography, UC San Diego, USA

Azam, F., Scripps Institution of Oceanography, UC San Diego, USA, fazam@ucsd.edu

Aluwihare, L. I., Scripps Institution of Oceanography, UC San Diego, USA, laluwihare@ucsd.edu

Details

Poster presentation

Session #:059
Date: 03/03/2017
Time: 15:30 - 16:30
Location: Poster/Exhibit Hall

Presentation is given by student: Yes

PosterID: 493