Assessing Performance of the Ascension Profiler: An Innovative Instrument for Collecting Filtered Microplastic Samples

One of the challenges we face in the PLASTINEST project is sampling microplastics in estuarine waters over key time scales of estuarine variability, as emphasized in our work « Physical processes matter! Recommendations for sampling microplastics in estuarine waters based on hydrodynamics ». Traditional sampling methods can encounter limitations, particularly when sampling at different phases of the tidal cycle, such as restricted time for in-situ sieve cleaning, contamination risks, or the need to transport large volumes of water.

In our pursuit to overcome these obstacles, we turned to the Ascension Profile—a cutting-edge instrument designed to excel in complex field conditions while minimizing contamination risks. The Ascension Profiler is a portable and tethered device capable of pumping and filtering water in-situ, even at greater depths, from the side of a small vessel or fixed installations. It offers real-time deployment capabilities and autonomous sampling missions, making it an ideal solution for our microplastic sampling needs in estuarine environments.

To address the specific challenges posed by energetic conditions and high levels of suspended sediments in macrotidal estuaries, our team embarked on meticulous lab experiments to evaluate the Ascension Profiler’s performance in hyperturbid waters. By varying suspended sediment concentrations and filter sizes, we assessed the instrument’s effectiveness in filtering water under simulated real-world conditions. These initial experiments were crucial in refining our methodologies and preparing for field deployments.

Building on the success of our lab trials, last February, we braved challenging weather conditions, to conduct field validations in the dynamic environment of the Garonne Tidal River. Collaborating with other essential instruments such as ADCP, CTD, and turbidity meters, we verified the Ascension Profiler’s reliability in real-world scenarios. The insights gained from these field validations have enabled us to further optimize our sampling protocols and methodologies for future field campaigns, enhancing our ability to understand and mitigate microplastic pollution in estuarine ecosystems.