Eco-Plastics in the Sea: Succession of Micro- and Macro-Fouling on a Biodegradable Polymer Augmented With Oyster Shell

Abstract

Impacts of Marine Plastic Debris (MPD) on marine ecosystems are among the most critical environmental concerns of the past three decades. Virgin plastic is often cheaper to manufacture than recycled plastics, increasing rates of plastic released into the environment and thereby impacting ecosystem health and functioning. Along with other environmental effects, MPD can serve as a vector for marine hitchhikers, facilitating unwanted organisms’ transport and subsequent spread. Consequently, there is a growing demand for more eco-friendly replacements of conventional plastic polymers, ideally with fit-for-purpose properties and a well-understood life cycle. We enriched polybutylene succinate (PBS) with three different concentrations of oyster shell to investigate the dynamics of biofouling formation over 18 weeks at the Nelson Marina, Aotearoa/New Zealand. Our study focused on oyster shell concentration as a determinant of fouling assemblages over time. While generally considered as a waste in the aquaculture sector, we used oyster shells as a variable of interest to investigate their potential for both, environmental and economic benefits. Using bacterial 16S and eukaryotic 18S rRNA gene metabarcoding, our results revealed that following immersion in seawater, time played a more critical role than substrate type in driving biofouling community structures over the study period. In total, 33 putative non-indigenous species (NIS) and 41 bacterial families with putative plastic-degrading capability were detected on the different substrates. Our analysis of NIS recruitment revealed a lower contribution of NIS on shell-enriched substrates than unadulterated polymers samples. In contrast, the different concentrations of oyster shells did not affect the specific recruitment of bacterial degraders. Taken together, our results suggest that bio-based polymers and composites with increased potential for biodegradability, recyclability, and aptitude for the selective recruitment of marine invertebrates might offer a sustainable alternative to conventional polymers, assisting to mitigate the numerous impacts associated with MPD.

Assessing the Plastisphere from Floating Plastics in the Northwestern Mediterranean Sea, with Emphasis on Viruses

“…In addition, we found numerous species of Planctomycetes, a bacterial phylum widely distributed in aquatic and terrestrial habitats, which play a considerable role in the global cycle of metals and nitrogen [ 59 ]. This group was also detected in the marine plastisphere of the South Atlantic [ 18 ] and South Pacific [ 60 ] Oceans, thus reinforcing the need to understand its role in biogeochemical cycles as a plastisphere member. Moreover, Roseovarius , another highly abundant and ubiquitous group we observed, comprises bacteria species known for their involvement in the sulfur cycle [ 61 ], as well as for its ability to degrade complex organic compounds [ 62 ].…”

Pest Alert Tool—a web-based application for flagging species of concern in metabarcoding datasets

“…We also see potential applicability of the tool for research purposes. For example, as part of the initial proof-of-concept test, the offline algorithm underlying the Pest Alert Tool has been tested in a study aimed at investigating potential affinity of marine NIS to particular biopolymer types in a marine deployment experiment ( 27 ). The algorithm allowed to quickly screen an extensive dataset obtained from 60 biofilm samples, representing 4225 unique amplicon sequence variants (ASVs) for a subset of marine NIS ASVs.…”

Does plastic type matter? Insights into non-indigenous marine larvae recruitment under controlled conditions

“…The PCR cycles for the 16S rRNA gene amplification were as follows: 94 °C for 3 min followed by 35 cycles of 94 °C (20 s), 52 °C (20 s) and 72 °C (30 s) with a final extension at 72 °C for 5 min. Negative (no-template) PCR controls were included in each PCR run ( Audrézet et al, 2022 ). Amplicon PCR products were purified using AMPure XP PCR Purification beads (Agencourt, Beverly, MA, USA), quantified using a Qubit Fluorometer (Life Technologies, Carlsbad, CA, USA) and diluted to 3 ng µL −1 .…”

“…Sequencing adapters and sample-specific indices were added to each amplicon via a second round of PCR using a Nextera Index kit. After that, 5 μL of each indexed sample was pooled, and a single clean-up of pooled PCR products was undertaken, as previously described by Audrézet et al (2022) . A bioanalyzer was used to check the quality of the library which was then diluted to 4 nM and denatured.…”