Guidelines for Harmonizing Ocean Surface Microplastic Monitoring Methods. Version 1.1.

Manta Net: The Golden Method for Sampling Surface Water Microplastics in Aquatic Environments

“…For example, an error of 48% was observed according to where the height is measured, between the lowest or the highest point reached by water (Karlsson et al, 2020). According to (Michida et al, 2019), the measurement of the water's height remains an issue when using a Manta net and can lead to under-or over-estimating the volume sampled and the resulting concentration of MPs.…”

“…The future for sampling MPs with a Manta net would require first a harmonization and then a standardization of all the parameters in order to compare all data produced worldwide. Some characteristics should be described in order to obtain a more precise version of the protocols proposed, for example, by Viršek et al, 2016;Michida, Y., et al, 2019 andCowger et al, 2020. First, we recommend that sampling be always carried out under calm conditions, to limit the effects of turbulence on the water column.…”

“…First, we recommend that sampling be always carried out under calm conditions, to limit the effects of turbulence on the water column. Sampling should not be carried out when timing and conditions are unsuitable, such as during high densities of natural particles or organisms, i.e., algae and plankton blooms (Michida, Y., et al, 2019). The environmental conditions, i.e., important metadata, should also always be recorded while a sample is collected, and include measurements of wind speed and direction, wave height, tide coefficient, sea temperature and weather conditions such as precipitation to allow comparisons with other survey results (Michida, Y., et al, 2019).…”

“…Sampling should not be carried out when timing and conditions are unsuitable, such as during high densities of natural particles or organisms, i.e., algae and plankton blooms (Michida, Y., et al, 2019). The environmental conditions, i.e., important metadata, should also always be recorded while a sample is collected, and include measurements of wind speed and direction, wave height, tide coefficient, sea temperature and weather conditions such as precipitation to allow comparisons with other survey results (Michida, Y., et al, 2019). Observation of the environmental conditions of the preceding few days is also very important, and can give good leads to explain the concentration of MPs in the water (Free et al, 2014;Sutton et al, 2016).…”

“…The boat used for sampling with a Manta net should sail under 3 knots to properly stabilize the sampling net and to avoid tearing it by accident and to avoid turbulent inflow at the net mouth (Michida et al, 2019) Table 1.…”