Corexit, oil and marine microgels

Chiu, Meng-Hsuen; Garcia, Santiago G.; Hwang, Benjamin; Claiche, Devon; Sanchez, G.; Aldayafleh, Reef; Santschi, Peter H.; Quigg, Antonietta; Chin, Wei‐Chun

doi:10.1016/j.marpolbul.2017.06.077

Cited by 13 publications

(2 citation statements)

References 30 publications

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“…In the last few years, considerable effort has been directed toward understanding how the ternary system (oil-dispersant-EPS) determines the fate and transport of oil (hydrocarbons) in the ocean, particularly considering the role of dispersants. Studies of oil, Corexit and organic matter, including exudates (EPS and TEP) may lead to conflicting observations as to the question of whether Corexit application promotes or hinders MOS formation and/or the subsequent sedimentation unless the findings are carefully dissected (Chiu et al, 2017;Passow et al, 2017Passow et al, , 2019. On one hand, Corexit application leads to significantly more oil droplets, thereby increasing the probability that oil is incorporated into marine snow.…”

Section: How Does the Presence Of The Resulting Ternary System (Oil-dispersant-eps) Modify The Fate Of The Oil?mentioning

confidence: 99%

Aggregation and Degradation of Dispersants and Oil by Microbial Exopolymers (ADDOMEx): Toward a Synthesis of Processes and Pathways of Marine Oil Snow Formation in Determining the Fate of Hydrocarbons

Quigg

Santschi

et al. 2021

Front. Mar. Sci.

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Microbes (bacteria, phytoplankton) in the ocean are responsible for the copious production of exopolymeric substances (EPS) that include transparent exopolymeric particles. These materials act as a matrix to form marine snow. After the Deepwater Horizon oil spill, marine oil snow (MOS) formed in massive quantities and influenced the fate and transport of oil in the ocean. The processes and pathways of MOS formation require further elucidation to be better understood, in particular we need to better understand how dispersants affect aggregation and degradation of oil. Toward that end, recent work has characterized EPS as a function of microbial community and environmental conditions. We present a conceptual model that incorporates recent findings in our understanding of the driving forces of MOS sedimentation and flocculent accumulation (MOSSFA) including factors that influence the scavenging of oil into MOS and the routes that promote decomposition of the oil post MOS formation. In particular, the model incorporates advances in our understanding of processes that control interactions between oil, dispersant, and EPS in producing either MOS that can sink or dispersed gels promoting microbial degradation of oil compounds. A critical element is the role of protein to carbohydrate ratios (P/C ratios) of EPS in the aggregation process of colloid and particle formation. The P/C ratio of EPS provides a chemical basis for the “stickiness” factor that is used in analytical or numerical simulations of the aggregation process. This factor also provides a relative measure for the strength of attachment of EPS to particle surfaces. Results from recent laboratory experiments demonstrate (i) the rapid formation of microbial assemblages, including their EPS, on oil droplets that is enhanced in the presence of Corexit-dispersed oil, and (ii) the subsequent rapid oil oxidation and microbial degradation in water. These findings, combined with the conceptual model, further improve our understanding of the fate of the sinking MOS (e.g., subsequent sedimentation and preservation/degradation) and expand our ability to predict the behavior and transport of spilled oil in the ocean, and the potential effects of Corexit application, specifically with respect to MOS processes (i.e., formation, fate, and half-lives) and Marine Oil Snow Sedimentation and Flocculent Accumulation.

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Section: How Does the Presence Of The Resulting Ternary System (Oil-dispersant-eps) Modify The Fate Of The Oil?mentioning

confidence: 99%

Aggregation and Degradation of Dispersants and Oil by Microbial Exopolymers (ADDOMEx): Toward a Synthesis of Processes and Pathways of Marine Oil Snow Formation in Determining the Fate of Hydrocarbons

Quigg

Santschi

et al. 2021

Front. Mar. Sci.

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“…Nevertheless, an overarching concern for practitioners is whether particular oil-spill responses, such as dispersant application, will enhance or inhibit MOS formation (Figure 2). Dispersants can reduce the overall stickiness of particles through either destabilization of TEP precursors (e.g., microgels; Chiu et al, 2017) or direct dispersal of TEP (Passow et al, 2017). This means that particles may collide but not stick together.…”

Section: Concluding Remarks and Recommendationsmentioning

confidence: 99%

Marine Oil Snow, a Microbial Perspective

Gregson

McKew

Holland³

et al. 2021

Front. Mar. Sci.

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Under certain conditions, dispersed crude oil in the sea combines with organisms, organic matter, and minerals to form marine oil snow (MOS), thereby contributing to the sinking of oil to the seafloor. Marine microbes are the main players in MOS formation, particularly via the production of extracellular polymeric substances. Distinct groups of microbes also consume the majority of the hydrocarbons during descent, leading to enrichment of the less bioavailable hydrocarbons and asphaltenes in the residue. Here we discuss the dynamics of microbial communities in MOS together with their impacts on MOS evolution. We explore the effects of dispersant application on MOS formation, and consider ways in which laboratory experiments investigating MOS formation can be more representative of the situation in the marine environment, which in turn will improve our understanding of the contribution of MOS to the fate of spilled oil.

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Colloids and Nanoparticles in Aquatic Systems

Santschi

2019

Encyclopedia of Water

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Colloids in the ocean are mainly composed of natural organic matter (NOM), with trace amounts of metals, nutrients, radionuclides, pollutants, and variable amounts of anthropogenically produced engineered nanoparticles and nanoplastics. Thus, state‐of‐the‐art instrumental techniques are required to unravel the chemical composition of colloids. Such studies revealed that colloidal macromolecular organic matter (COM) contain aquagenic substances (composed of microbially produced exopolymeric substances, EPS, gels, transparent exopolymer particles, TEP, and TEP precursors) and pedogenic substances (humic and fulvic matter). COM can act as glue or as soap; can be bioavailable and biodegradable or refractory; and contain different moieties that act as metal chelators, antioxidants, or absorber of hydrophobic pollutants. EPS in aquatic systems, mostly composed of polysaccharides and proteins, can form not only biofilms but also marine snow (MS) or marine oil snow (MOS), and are important in initiating and maintaining aggregation and sedimentation processes. These processes can also be traced by natural radionuclides that have colloidal fractions. These aggregation processes lead to “colloidal pumping” (aggregation to form larger particles) of trace substances bound to EPS and other macromolecular NOM compounds that counteract the prevailing pathway of degradation of macromolecular NOM to low‐molecular‐weight molecules.

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Corexit, oil and marine microgels

Cited by 13 publications

References 30 publications

Aggregation and Degradation of Dispersants and Oil by Microbial Exopolymers (ADDOMEx): Toward a Synthesis of Processes and Pathways of Marine Oil Snow Formation in Determining the Fate of Hydrocarbons

Aggregation and Degradation of Dispersants and Oil by Microbial Exopolymers (ADDOMEx): Toward a Synthesis of Processes and Pathways of Marine Oil Snow Formation in Determining the Fate of Hydrocarbons

Marine Oil Snow, a Microbial Perspective

Colloids and Nanoparticles in Aquatic Systems

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