Industrial mining trial for polymetallic nodules in the Clarion-Clipperton Zone indicates complex and variable disturbances of meiofaunal communities

• DOI: 10.3389/fmars.2024.1380530
• Publication Date: 2024-05-08T04:41:42Z
• Authors: Nene Lefaible; Lara Macheriotou; Ellen Pape; Massimiliano Molari; Matthias Haeckel; Daniela Zeppilli; Ann Vanreusel
• Keywords: ELEMENT FLUXES; IMPACTS; 0106 biological sciences; Science; Q; BIOGEOCHEMICAL PROCESSES; Biology and Life Sciences; General. Including nature conservation, geographical distribution; environmental impacts; QH1-199.5; ECOLOGY; 01 natural sciences; deep-sea mining; benthic ecosystem; Earth and Environmental Sciences; polymetallic nodules; metabarcoding; PATTERNS; nematoda; NEMATODE ASSEMBLAGES; SEDIMENTS; SCALE

Following several small-scale benthic disturbance experiments, an industrial polymetallic nodule collector trial was conducted by the company Global Sea mineral Resources (GSR) in their exploration contract area Clarion-Clipperton Zone using pre-prototype vehicle Patania II (PATII). In this study, meiofaunal (i.e., nematode abundance, ASV diversity and genus composition) environmental grain size, total organic carbon/total nitrogen pigment) properties are compared between categories Pre-impact, Collector Impact Plume Impact). One week after trial, proxies for food availability within sediments were altered with lower carbon (TOC) pigment CPE: sum of Chlorophyll a phaeopigments) values. Albeit not significant, observed decrease abundance diversity, further indicate consequences removal ecologically important surface sediment layer PATII tracks. Next to removal, exposed modified different ways (e.g., central strips, parallel caterpillar imprints alternating bands depressions/ripples interface patches) also subject heavy collector-induced blanketing. We propose that these cumulative impacts have led intricate seabed modifications various levels intensity which resulted high variability observed. Adjacent nodule-rich areas Impact) received considerable deposition (2-3 cm) defined significantly sources (CPE, TOC, ratio) observation enrichment higher average diversity; although statistically non-significant), but mechanisms behind ecological changes suspended material-surface fluxes, passive dispersal fauna plume vs. active upward migration “viability” redeposited fauna) remain unresolved. conclude complex pressure-response relationships associated combined degree natural spatial temporal abyssal communities sedimentary parameters, complicates quantitative assessment deep-sea mining disturbances.