Page 38 - AJWEP-22-6

Fattorini

a significant role in the atmospheric transport and to sand particles, forming persistent, resistant oil-sand
deposition of volatile oil components and the formation agglomerates. These tarballs and other oil residues can
of aerosol and spray. This can lead to the widespread penetrate seashore sediments, migrate, and be released.
dispersal of oil hydrocarbons into the atmosphere. 88-90 This infiltration can lead to long-term contamination
Hydrocarbons transported through the atmosphere can of the intertidal and subtidal zones. 88,90 Stratification
move to destinations very far from the primary emission can occasionally occur within the sediments, with oil
sources, reaching the surface of the water, beaches, or burying itself at various depths. This buried oil can
other emerged areas, through wet or dry deposition. 88,90 continue to undergo mixing with sediments and deep
Oil on the water surface or transported in the storage, making its remediation challenging. Like in
atmosphere can directly threaten seabirds, which are the open ocean, bioaccumulation and biotransformation
particularly vulnerable to this contamination. The more in biota may occur within the shoreline ecosystem,
viscous components adhere to the plumage of these affecting benthic organisms and potentially their
animals, causing movement and flight difficulties, consumers. 11,27,62,82 In addition, the seabirds can be
thermoregulation disorders, impairment of various directly endangered due to contact with oiled shorelines,
abilities, including catching food, and toxicity and emphasizing the vulnerability of avian species to coastal
death. 11,27,62,82 oiling. 62,82
Further interactions occur within the water column. Hydrocarbon mixtures in the sea can undergo various
Dissolution from oil slicks may occur when water- physicochemical and biological degradation processes
soluble components of the oil dissolve directly into at multiple stages. Although these processes determine
the seawater. The sudden mixing of oil slicks and a natural mitigation of hydrocarbon contamination,
surface water favors the formation of emulsions (oil they can potentially lead to the formation of different
emulsification in waters or waters in oil emulsion), compounds often characterized by a greater solubility
where small oil droplets are dispersed within the water in water and potentially a greater toxicity in living
column, often stabilized by natural surfactants. The organisms. 35-40,89 Microbial biodegradation represents the
heavier components tend to slowly disperse deep into primary natural attenuation mechanism for hydrocarbons
the water column, while the lighter ones return to the in marine environments. This complex process involves
surface, re-aggregating with the oil slicks and thus diverse microbial communities, primarily bacteria and
promoting a cycle. 90 fungi, breaking down hydrocarbons into less harmful
Simultaneously, oil can undergo sorption on substances, ultimately leading to mineralization into
suspended solids, where oil molecules adhere to carbon dioxide or methane. The efficacy and specific
particulate matter, increasing their density and pathways of this degradation are critically dependent
potentially leading to sedimentation. 88,90 Within the water on oxygen availability, leading to distinct aerobic and
column, large oil droplets collapse, and dispersion and anaerobic processes. 36,37,89
dissolution continue, breaking down the oil into smaller Aerobic biodegradation is the dominant and generally
components. These processes facilitate the uptake more rapid process in oxygen-rich marine waters,
and release from sediments. Once oil settles, it can be such as the surface layers and oxic sediments. A series
re-released into the water column, initiating a recurring of specialized microorganisms possess enzymatic
cycle. All these transports and migrations contribute to systems, particularly alkane hydroxylase complexes,
bioaccumulation and biotransformation in biota, with that initiate the degradation of hydrocarbons. 36,37,41,89,91
various marine vertebrates (benthic or pelagic fish) and The primary mechanism involves the incorporation of
invertebrates (i.e., mollusks, polychaetes, and algae) molecular oxygen into the hydrocarbon molecule by
taking up oil compounds, which are then metabolized monooxygenases, forming an alcohol. This alcohol
and accumulated within their tissues, with significant is then oxidized to a fatty acid, which undergoes
toxicological effects on marine life. 11,62 successive β-oxidation cycles, progressively shortening
As oil drifts toward the coast, driven by currents the carbon chain and finally forming acetyl-CoA.
and winds, it can lead to onshore stranding. Once on Acetyl-CoA then enters the tricarboxylic acid cycle for
the shoreline, the interactions become more complex, complete mineralization to carbon monoxide and water,
largely dependent on the characteristics of the beach, generating energy for microbial growth. 41,91 Biosurfactant
the presence of rocks, and the type of sediments and production by certain aerobic microorganisms enhances
sands. Oil mixed with sand and the formation of the bioavailability of hydrophobic hydrocarbons by
90
“tarballs” is a common phenomenon, where oil adheres emulsification, making them more accessible for

Volume 22 Issue 6 (2025) 32 doi: 10.36922/AJWEP025290224