Diverse groups of fungi are associated with plastics in the surface waters of the Western South Atlantic and the Antarctic Peninsula

Abstract

Marine plastic pollution has a range of negative impacts for biota and the colonization of plastics in the marine environment by microorganisms may have significant ecological impacts. However, data on epiplastic organisms, particularly fungi, is still lacking for many ocean regions. To evaluate plastic associated fungi and their geographic distribution, we characterised plastics sampled from surface waters of the western South Atlantic (WSA) and Antarctic Peninsula (AP), using DNA metabarcoding of three molecular markers (ITS2, 18S rRNA V4 and V9 regions). Numerous taxa from eight fungal phyla and a total of 64 orders were detected, including groups that had not yet been described associated with plastics. There was a varied phylogenetic assemblage of predominantly known saprotrophic taxa within the Ascomycota and Basidiomycota. We found a range of marine cosmopolitan genera present on plastics in both locations, i.e., Aspergillus, Cladosporium, Wallemia and a number of taxa unique to each region, as well as a high variation of taxa such as Chytridiomycota and Aphelidomycota between locations. Within these basal fungal groups we identified a number of phylogenetically novel taxa. This is the first description of fungi from the Plastisphere within the Southern Hemisphere, and highlights the need to further investigate the potential impacts of plastic associated fungi on other organisms and marine ecosystems.

Microplastics accumulate fungal pathogens in terrestrial ecosystems

“…Evidence for the presence of pathogenic bacteria on plastics already exists for aquatic biomes 23 , 25 and is currently in the focus of microplastics research. Fungi have been largely neglected in this endeavour despite their enormous diversity 35 , ecological significance 36 , affinity for plastic 16 , 17 and impact as pathogens 37 , 38 . Aggravatingly, terrestrial ecosystems in general and human settings in particular have been extremely poorly covered, despite being the first and major sinks of MP 39 , 40 .…”

“…The hydrophobic surface of plastic waste provides an ideal environment for microbial colonisation and biofilm formation, and represents a protective ecological niche, the so-called ‘plastisphere’ 13 . These epiplastic communities harbour Archaea and Bacteria 13 – 15 , as well as unicellular and oligocellular eukaryotes including fungi 16 , 17 , and have been found on plastics from marine, limnic, and fluvial ecosystems in numerous biomes from the equator to the polar regions 18 . Metagenomic studies show that MP selects for microbial communities that are different from the surrounding environment 19 , and whose composition and succession is subject to spatial 20 and seasonal influence 19 as well as polymer type 21 .…”

Changes in Phytoplankton Communities Along the Northern Antarctic Peninsula: Causes, Impacts and Research Priorities

“…Since the current knowledge is not enough to estimate the risk of introduction or assess its potential impact, it remains unclear how the expansion or introduction of species could alter the phytoplankton community in the NAP. Nevertheless, in situ monitoring and specific actions focused on potential introduction pathways, such as ballast waters (Frenot et al, 2005) and marine plastic debris (Lacerda et al, 2019(Lacerda et al, , 2020, should be introduced in the future.…”

<em> </em>Current Research on Microbe-Plastic Interactions in the Marine Environment

“…Most plastisphere metabarcoding studies have targeted the overall eukaryotic fraction using the 18S rRNA gene as a marker 7,31,50,85,86,88,90,100,127,148,150 , but some have focussed particularly on the fungal plastisphere fraction 31,90 , in some cases employing fungal-specific ITS 148 or ITS2 31,87 marker genes.…”

“…Several studies have also reported that certain fungal taxa are able to degrade plastics, however only three of these strains are marine (Zalerion maritimum 92 , Aspergillus tubingensis and A. flavus 221 ; reviewed by Rogers et al 197 and 199 ). Nevertheless, the search for marine plastic degraders has prompted a special interest in fungi and, in recent years, the fungal fraction of the plastisphere -which has been found to comprise approximately 2.8-3% of the overall eukaryote sequences in field and lab incubations in Baltic (along an estuarine continuum) and North Sea waters, respectively 90,100 -has been specifically targeted by at least four studies 31,87,90,148 .…”