Dealing with the promise of metabarcoding in mega-event biomonitoring:
EXPO2015 unedited data
Abstract
As human activities on our planet persist, causing widespread and
irreversible environmental degradation, the need to biomonitor
ecosystems has never been more pressing. These circumstances have
required a renewal in monitoring techniques, encouraged by necessity to
develop more rapid and accurate tools which will support timely
observations of ecosystem structure and function. The World Exposition
(from now ‘EXPO2015’) hosted in Milan from May to October 2015 was a
global event that could be categorized as a mega-event, which can be
defined as an acute environmental stressor, possibly generating
biodiversity alteration and disturbance. During the six months of
EXPO2015, exhibitors from more than 135 countries and 22 million
visitors insisted on a 1.1 million square meters area. Faced with such a
massive event, we explore the potential of DNA metabarcoding using three
molecular markers to improve the understanding of anthropogenic impacts
in the area, both considering air and water monitoring. Furthermore, we
explore the effectiveness of the taxonomy assignment phase considering
different taxonomic levels of analysis and the use of data mining
approaches to predict sample origin. Unless the degree of taxa
identification still remains open, our results showed that DNA
metabarcoding is a powerful genomic-based tool to monitor biodiversity
at the microscale, allowing us to capture exact fingerprints of specific
event sites and to explore in a comprehensive manner the eukaryotic
community alteration. With this work, we aim to disentangle and overcome
the crucial issues related to the generalization of DNA metabarcoding in
order to support future applications.