Work Package 2: Microplastic uptake by groundwater food webs

Rationale
Microplastics enter surface freshwater food webs directly, e.g. through uptake
from the water/ sediment and/or indirectly, through consumption of contaminated prey. The uptake mechanisms of microplastics and their contaminants in groundwater food webs, how this differs across aquifer types and environmental constraints (e.g.
nutrients) are completely unknown. This knowledge gap critically hampers assessment of the impact of microplastics on the essential ecosystem services that groundwater food webs deliver to humankind.

Research question
How do microplastics and their associated contaminants enter groundwater food webs, and how is their uptake dependent on microplastics properties (size, concentration), constraints such as nutrient concentration and also aquifer type?

Objective
Identify pathways of microplastic uptake into groundwater food webs and the impact of microplastic properties and major environmental constraints such as nutrients on uptake.

Methods
We will use microcosm arrays that have greater realism in simple groundwater systems (low abundance and species) than in more complex surface water systems. We will establish microcosms with fluorescently labelled microplastics mixes (size range, concentrations and types informed by WP 1 findings) with differing 2-
element food chains within the groundwater food web. Further experiments will focus on the effect of nutrient concentration on microplastic uptake by protozoans
as nutrients stimulate bacterial growth and bacterial feeding protozoans are crucial members of the groundwater community. We will also explore uptake of microplastics by macro-crustaceans using material and communities sampled across 3 aquifer types. 

Work Package lead
Dr Julia Reiss
julia.reiss@roehampton.ac.uk