Microplastic (MP) particles spread all over the marine trophic chain, latently threatening ecosystems’ and human health. To tackle the problem, the traits that favor their accretion across habitats must be identified. Seagrass meadows are key ecosystems of soft bottoms worldwide. Their leaves trap particles from the water column, favoring their burial into the sediment. Several studies have confirmed the presence of MP in these meadows’ sediments, but less light has been shed on the features that mediate their accrual. Here we studied the MP accumulation mediating role of seagrass epigeal structural complexity of an intermediate-sized species. Two replicated habitat types (vegetated, unvegetated-UV) and levels of structural complexity (high-HC, low-LC) were assessed in natural meadows (Canary Islands). Sedimentary MP abundance was determined from cores of superficial sediment. We found MPs in the sediments of all studied meadows, covering diverse shapes, sizes and colors, being the 1-2 mm transparent fibers the most profuse. MP abundance in the sediments inside HC meadows significantly exceeded that of their abutting UV sediments. MP abundance inside LC meadows equaled that of their abutting UV sediments, significantly exceeding that of UV sediments abutting HC meadows. Our results evince that epigeal structural complexity of seagrass meadows mediate their MP sink capacity. HC meadows function as enhanced sinks when compared to UV sediments. Conversely, LC meadows lack this boosted filtering capacity, and their abutting UV sediments function as enhanced MP sinks instead.

Primary Presenter: Silvia Oliva Pérez, Universidad de La Laguna (silviaolivaperez@gmail.com)

Authors:

Cristina Villanova Solano, Universidad de La Laguna  ()

José Carlos Mendoza Durán, Instituto Español de Oceanografía  ()

Cintia Hernández Sánchez, Universidad de La Laguna  ()

Javier Hernández Borges, Universidad de La Laguna  ()

Carmen B. de los Santos, Centro de Ciências do Mar - Universidade do Algarve  ()