QUANTITATIVE IMPROVEMENTS IN MARINE ZOOPLANKTON METABARCODING USING PCR BIAS CORRECTION

Recent advances in DNA metabarcoding have revolutionized how we measure and monitor zooplankton. However, methodological biases such as those introduced during PCR amplification remain a critical challenge in our quantitative interpretation of molecular-based measurements. In this study, we applied a novel PCR-bias correction method to environmental samples of marine zooplankton. We employed variable PCR cycle experiments to calibrate and attempt to mitigate amplification differences across the mixed community. This approach, only trialed in microbiome studies, was adapted to marine zooplankton by pooling samples from a range of environmental conditions and estimating taxon-specific amplification efficiencies. Our study focuses on size-fractionated mesozooplankton from the California Current Ecosystem, where we examined the variability in PCR amplification for key zooplankton taxa, including copepods and euphausiids. By integrating metabarcoding with Zooscan imaging of the same samples, we assessed the improvements in quantifying zooplankton community composition and abundance following bias correction. The results demonstrated enhanced agreement between molecular and morphological estimates for abundant taxa such as calanoid copepods. This work represents the first application of PCR bias correction to marine zooplankton and highlights its potential for improving the quantitative reliability of metabarcoding data. This methodology can be a critical tool for ecologists aiming to integrate DNA-based approaches with traditional morphological methods.

Presentation Preference: Oral

Primary Presenter: Dante Capone, Scripps Institution of Oceanography (dcapone@ucsd.edu)

Authors:

Hannah Budroe, University of Georgia  (hmb25721@uga.edu)

Ramon Gallego, Universidad Autónoma de Madrid - Unidad de Genética  (ramongallego@gmail.com)

Stephanie Matthews, University of Washington  (samatt@uw.edu)

Michelle Nixon, Pennsylvania State University  (pistnerm1@gmail.com)

Jeff Bowman, University of California San Diego, Scripps Institution of Oceanography  (jsbowman@ucsd.edu)

Moira Décima, University of California San Diego, Scripps Institution of Oceanography  (mdecima@ucsd.edu)

Justin Silverman, Pennsylvania State University  (JustinSilverman@psu.edu)