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Fattorini

composed of hydrogen and carbon atoms, existing in a migrate and escape into the marine environment. These
broad spectrum of physical states, from volatile gases, deep-sea features are therefore considered natural
such as methane to heavy, viscous liquids, and solid sources of hydrocarbons in the ocean. 22,23 Moreover,
tars. Their presence in the marine environment is not aquatic organisms, including phytoplankton, bacteria,
4
recent, considering that natural geological processes and algae, naturally produce small quantities of diverse
have continuously introduced these compounds into the hydrocarbons, which contribute to the background
oceans for millions of years, shaping unique ecosystems levels in seawater. Although these natural processes are
24
around several localized inputs. 1,5-7 However, the advent constant, a continuous degradation of hydrocarbons is
of the industrial age and the escalating global reliance operated by specialized endemic microbial populations,
on fossil fuels have dramatically altered the magnitude, demonstrating the ocean’s inherent capacity for natural
frequency, and composition of hydrocarbon inputs, attenuation. 25
transforming what were once isolated natural seepage In contrast, anthropogenic sources introduce
into widespread contamination events. 8-10 hydrocarbons into the marine environment with
The ecological and economic significance of significantly greater magnitude and frequency, often in
marine ecosystems necessitates a comprehensive concentrated, acute events. The primary anthropogenic
8,9
understanding of hydrocarbon dynamics. These contributor is the petroleum industry, encompassing
environments, ranging from surface waters enriched exploration, production, transport, and refining
with phytoplankton at the base of the aquatic food activities. Major oil spills from accidents (e.g., Exxon
webs to deep-sea hosting chemosynthetic communities Valdez, Prestige), offshore drilling blowouts (e.g.,
and an intricate benthic ecosystem, are all potentially Deepwater Horizon), and pipeline ruptures represent
susceptible to hydrocarbon exposure of both natural catastrophic point source inputs that release vast
and anthropogenic origins. 11-13 Hydrocarbons can exert quantities of crude oil over short periods, overwhelming
deleterious effects at every trophic level, impacting natural degradation processes. 26-28 Beyond these high-
organisms from unicellular species to apex predators, profile incidents, chronic operational discharges from
such as marine mammals and seabirds. 14,15 Furthermore, shipping (e.g., ballast water, engine room effluence) and
the recreational and economic value of coastal areas, discharges of produced water from offshore oil and gas
including vital fisheries, aquaculture operations, and platforms may increase the background level of global
thriving tourism industries, is directly threatened by pollution. 29-31 Moreover, land-based sources, such as
hydrocarbon pollution, leading to significant financial urban and industrial runoff carrying hydrocarbons
losses and long-term environmental damage. The from road spills, industrial effluents, and atmospheric
8,9
inherent toxicity and bioaccumulation potential of deposition of combustion byproducts from vehicles and
many hydrocarbon compounds pose a multifaceted industries, also represent significant and diffuse inputs
threat, prompting extensive scientific inquiry into their to water bodies. 32,33 Notably, the chemical composition
fate and effects in marine systems. 1,8,11,14,15 of anthropogenic hydrocarbons, particularly refined
Natural hydrocarbon sources in the marine products, often markedly differs from that of natural
environment primarily include geological seeps and seeps, containing elevated concentrations of more
biogenic production. 12,13,16,17 Deep-sea seeps found along toxic and bioavailable compounds, exacerbating the
continental margins worldwide (e.g., Gulf of Mexico, ecological impacts. 34
Santa Barbara Channel) continuously release oil and gas In the marine environment, aliphatic hydrocarbon
from subsurface reservoirs through fissures and faults mixtures can undergo a complex series of physical,
in the seabed. 5,6,18 These natural inputs have sculpted chemical, and biological transformations that govern
unique chemosynthetic ecosystems, where specialized their distribution, persistence, and ultimate fate. 1,2,35-37
microbial communities thrive on hydrocarbons and sulfur Processes, such as spreading, evaporation of volatile
compounds, forming the base of unique food webs. At components, dissolution into the water column,
the same time, volcanic activity and hydrothermal vents wave dispersion, and emulsification can rapidly alter
also contribute a minor amount of hydrocarbons. 19-21 oil physical characteristics. 1,36,37 In surface waters,
Submarine pockmarks are seabed depressions or craters chemical transformations include photo-oxidation by
that typically form through episodic or continuous sunlight, which can lead to the formation of more polar
expulsion of subsurface fluids, such as methane gas and and sometimes more toxic compounds. 38-40 However,
other hydrocarbons. They act as geological pathways microbial degradation represents the most critical natural
for hydrocarbons stored deep within the Earth’s crust to attenuation pathway, where diverse marine bacteria and

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