Microbial carrying capacity and carbon biomass of plastic marine debris

Abstract

Trillions of plastic debris fragments are floating at sea, presenting a substantial surface area for microbial colonization. Numerous cultivation-independent surveys have characterized plastic-associated microbial biofilms, however, quantitative studies addressing microbial carbon biomass are lacking. Our confocal laser scanning microscopy data show that early biofilm development on polyethylene, polypropylene, polystyrene, and glass substrates displayed variable cell size, abundance, and carbon biomass, whereas these parameters stabilized in mature biofilms. Unexpectedly, plastic substrates presented lower volume proportions of photosynthetic cells after 8 weeks, compared to glass. Early biofilms displayed the highest proportions of diatoms, which could influence the vertical transport of plastic debris. In total, conservative estimates suggest 2.1 × 10 21 to 3.4 × 10 21 cells, corresponding to about 1% of the microbial cells in the ocean surface microlayer (1.5 × 10 3 to 1.1 × 10 4 tons of carbon biomass), inhabit plastic debris globally. As an unnatural addition to sea surface waters, the large quantity of cells and biomass carried by plastic debris has the potential to impact biodiversity, autochthonous ecological functions, and biogeochemical cycles within the ocean.

Contribution of stochastic processes to the microbial community assembly on field‐collected microplastics

“…The functions related to chemoheterotrophy, aerobic chemoheterotrophy, and fermentation were identified as the top three key differentiators of microplastic and water samples, confirming the enrichment of heterotrophs on microplastics. The potential reason can be that microplastics have the capacity to entrap organic carbon and nitrogen from the surrounding oligotrophic water (Zhao et al ., 2021). Overall, regarding both taxa composition and predicted functional groups, our results confirmed that microplastics may exert selection pressure on the formation of plastisphere communities.…”

Microbial Communities on Plastic Polymers in the Mediterranean Sea

“…For visualization of biofilms and plastic surfaces, several studies have applied scanning electron microscopy (SEM) ( Carson et al, 2013 ; Zettler et al, 2013 ; Bryant et al, 2016 ; Kirstein et al, 2018 , 2019 ; Miralles et al, 2018 ). With SEM analysis, Eukarya were identified, of which diatoms are early and/or dominant colonizers ( Eich et al, 2015 ; Dudek et al, 2020 ; Zhao et al, 2020 ). However, SEM does not allow the identification of the attached prokaryotes.…”

The Devil on a Dying Bay: Brazilian Marine Plasticarianism at Guanabara Bay

“…Mined petrochemicals are the feedstock for making plastics. Consumer used and discarded plastic is blown by wind and moved by water flowing through landscapes into the world's ultimate trash receptacle, the world's ocean [1][2]; about 1% of microbial cells in the world-ocean surface microlayer inhabit plastic debris, making that debris an unnatural habitat for oceanic flora [3]. Freshwater runoff from streams and rivers which debauch into Rio de Janeiro's GB carry floating plastic debris which, upon natural comminution, becomes a major microplastic [4] contamination macro-problem within the Holocene gulf [5] as well as the adjacent continentalshelf [6].…”

“…The literature on pollution of the seas is vast and tends always to grow, particularly with regard to plastic waste [1,3,5,6,8,10]. The pollution caused by the accumulation of plastic in river estuaries, soils and oceans is perhaps the main signature of consumerism and slouch, traces of a radically aggressive and possibly lethal inhuman modern-day consumerist life-style.…”