and algae during the degradation of hydrocarbons in the sea, pointing out the
importance of two crucial evidences: (1) the exchange of mutual benefits that help
to cope with the variability of the aquatic environment and (2) the syntrophic
behavior in the consumption of hydrocarbons. Moreover, according to the literature,
it appeared that phycosphere is a complex system that should be studied by a holistic
approach to understand the natural occurring interaction between algae and bacteria
that can contribute to the success of in situ bioremediation processes.
Keywords Algae bacteria interaction · Bioremediation in marine environment ·
Hydrocarbon-degrading bacteria
7.1 Introduction
7.1.1 Oil Pollution in Marine Environment
Petroleum is an important industrial raw material and power source widely used in
multiple fields. Given the common understanding on the necessity to use renewable
energy sources, the projection on the use of fossil fuel in the countries belonging to
the Organisation for Economic Co-operation and Development shows a decline by
2050 (Itopf.com 2016), notwithstanding the fact that the global demand for energy is
expected to rise by 25% in the period 2014–2040 and in 2040, one-third of the
world’s energy would be still provided by oil (Selin 2013). This is not consequencefree as historically demonstrated by the number and severity of the incidents that
have occurred during oil extraction, refinery, naval operation and transport, especially in marine environment (O’ Brien 2004; Gomez and Sartaj 2014; Khudur et al.
2015). According to Fernandez-Macho (2016), European Atlantic countries are at
greater risk of oil pollution, followed by Mediterranean coastlines, where Italy and
Greece seem to be much more exposed to the hazard. Moreover, Mediterranean
coastline is littered with several oil-polluted sites, which have experienced intensive
industrialization (Daffonchio et al. 2013). Some of these (i.e., Gela and Priolo, Italy)
were declared “at high risk of environmental crisis” in 1990, but little has been done
for the cleaning-up of the polluted sites and to reduce environmental damages
attributable to pollution exposure (Guerriero et al. 2011). Such conditions dramatically reduce the extent of marine areas contributing to ecosystems services (Sousa
et al. 2016). Oil pollution in marine environment threatens public and animal wellbeing, impairs environmental health, not to mention socioeconomic relapses, overall
for marine and maritime activities and industries and related jobs. The source of oil
pollution in marine environment can have natural origin as seepage, but a large
proportion derives from anthropic activities such as offshore production, shipping,
refinery operations, and industrial and urban runoff (Group of Experts on the
Scientific Aspects of Marine Environmental Protection 2007; Farrington and
McDowell 2004; Lindgren et al. 2016). Generally, oil spillages can be distinguished
into large (macro) and small (micro) spills (Sardi et al. 2017). Macro oil-spill, caused
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R. Denaro et al.
importance of two crucial evidences: (1) the exchange of mutual benefits that help
to cope with the variability of the aquatic environment and (2) the syntrophic
behavior in the consumption of hydrocarbons. Moreover, according to the literature,
it appeared that phycosphere is a complex system that should be studied by a holistic
approach to understand the natural occurring interaction between algae and bacteria
that can contribute to the success of in situ bioremediation processes.
Keywords Algae bacteria interaction · Bioremediation in marine environment ·
Hydrocarbon-degrading bacteria
7.1 Introduction
7.1.1 Oil Pollution in Marine Environment
Petroleum is an important industrial raw material and power source widely used in
multiple fields. Given the common understanding on the necessity to use renewable
energy sources, the projection on the use of fossil fuel in the countries belonging to
the Organisation for Economic Co-operation and Development shows a decline by
2050 (Itopf.com 2016), notwithstanding the fact that the global demand for energy is
expected to rise by 25% in the period 2014–2040 and in 2040, one-third of the
world’s energy would be still provided by oil (Selin 2013). This is not consequencefree as historically demonstrated by the number and severity of the incidents that
have occurred during oil extraction, refinery, naval operation and transport, especially in marine environment (O’ Brien 2004; Gomez and Sartaj 2014; Khudur et al.
2015). According to Fernandez-Macho (2016), European Atlantic countries are at
greater risk of oil pollution, followed by Mediterranean coastlines, where Italy and
Greece seem to be much more exposed to the hazard. Moreover, Mediterranean
coastline is littered with several oil-polluted sites, which have experienced intensive
industrialization (Daffonchio et al. 2013). Some of these (i.e., Gela and Priolo, Italy)
were declared “at high risk of environmental crisis” in 1990, but little has been done
for the cleaning-up of the polluted sites and to reduce environmental damages
attributable to pollution exposure (Guerriero et al. 2011). Such conditions dramatically reduce the extent of marine areas contributing to ecosystems services (Sousa
et al. 2016). Oil pollution in marine environment threatens public and animal wellbeing, impairs environmental health, not to mention socioeconomic relapses, overall
for marine and maritime activities and industries and related jobs. The source of oil
pollution in marine environment can have natural origin as seepage, but a large
proportion derives from anthropic activities such as offshore production, shipping,
refinery operations, and industrial and urban runoff (Group of Experts on the
Scientific Aspects of Marine Environmental Protection 2007; Farrington and
McDowell 2004; Lindgren et al. 2016). Generally, oil spillages can be distinguished
into large (macro) and small (micro) spills (Sardi et al. 2017). Macro oil-spill, caused
196
R. Denaro et al.