Emulating Deep-Sea Bioremediation: Oil Plume Degradation by Undisturbed Deep-Sea Microbial Communities Using a High-Pressure Sampling and Experimentation System

Abstract

Hydrocarbon biodegradation rates in the deep-sea have been largely determined under atmospheric pressure, which may lead to non-representative results. In this work, we aim to study the response of deep-sea microbial communities of the Eastern Mediterranean Sea (EMS) to oil contamination at in situ environmental conditions and provide representative biodegradation rates. Seawater from a 600 to 1000 m depth was collected using a high-pressure (HP) sampling device equipped with a unidirectional check-valve, without depressurization upon retrieval. The sample was then passed into a HP-reactor via a piston pump without pressure disruption and used for a time-series oil biodegradation experiment at plume concentrations, with and without dispersant application, at 10 MPa and 14οC. The experimental results demonstrated a high capacity of indigenous microbial communities in the deep EMS for alkane degradation regardless of dispersant application (>70%), while PAHs were highly degraded when oil was dispersed (>90%) and presented very low half-lives (19.4 to 2.2 days), compared to published data. To our knowledge, this is the first emulation study of deep-sea bioremediation using undisturbed deep-sea microbial communities.

Crude Oil and Its Burnt Residues Induce Metamorphosis in Marine Invertebrates

“…The samples were injected diluted in 100 μL ultrapure DCM and spiked with the IS to 100 ppb concentration. The aromatic hydrocarbon components were quantified against the internal standard using an assumed response factor of 1 (see Antoniou et al (2022) 47 for further details regarding the instrumental analysis parameters). The precision of the analytical method, evaluated in terms of the repeatability of the experimental results (n = 8; in spiked samples) and expressed in terms of relative standard deviation, was ranged from 1.6 to 4.2% for individual PAHs.…”