101
mones, as Baweja et al. (2009) indicated. Competence is defined as the status in
which a cell must be able to perceive, transduce and respond to a signal (Osborne
and McManus 2005). There was a confused but apparently accepted idea that any
part of any alga was competent with respect to plant growth regulators, but this is
not so (Baweja et al. 2009). All in all, our knowledge of the role of volatiles in algal
reproduction is so little and so disperse but truly incredible to discover.
5.2 Volatile Compounds Are All Around: How Do Algae
Smell?
Very briefly, algae smell of short-chained aromatic volatiles, the most common
components as benzaldehyde, which contribute to the flavour of processed algae
and algae-based products, something of great importance in the industry, since their
identification would determine the quality and freshness of a product as their organoleptic features are related to processed foods (Yamamoto et al. 2014). Other wellcharacterised volatile organic compounds have been identified, such as alkanes,
alkenes, alcohols, terpenes, carbonyls, esters, halogen, compounds containing sulphur and acids (Loreto and Schnitzler 2010; Klaschka and Kolossa-Gehring 2007;
Holopainen 2004; Bleecker 2000).
Halogenated compounds are the most extensively studied volatiles. The production of halomethanes from macroalgae has been reported to vary by up to three
orders of magnitude depending on the geographical location (Schall et al. 1994;
Manley et al. 1992) and by anthropogenic effect (Goodwin et al. 1997).
Specifically, chlorinated compounds have been encountered in algae, in spite of
being relatively rare in living organisms. Their interest lies in their antibacterial
properties, such as the green alga Chara globularis, reportedly emitting against
Staphylococcus aureus (Bankova et al. 2001).
Micro- and macroalgae also contribute to a large extent to the production of bromine and polybromomethanes in marine environments (Paul and Pohnert 2011;
Carpenter et al. 2003), and their presence in the atmosphere may directly affect
human health, cloud condensation nuclei formation and climate (Pirjola et al. 2000).
Moreover, bromine is known to be the halogen often found in marine-derived compounds (Abrahamsson et al. 1995). It is estimated that around 70% of the world’s
bromoform is produced by macroalgae (Carpenter and Liss 2000).
Furthermore, seaweeds also produce other haloforms, whose emission rates
depend on light intensity and pH changes. For example, halomethane production has
been reported in the green algae Enteromorpha and Ulva, in the giant kelp Macrocystis
(Goodwin et al. 1997) and in the brown seaweeds Ascophyllum, Fucus and Laminaria
and in the red seaweeds Gelidium, Asparagopsis, Eucheuma and Mastocarpus
(Garcia-Jimenez et al. 2013; Mtolera et al. 1996 and references herein).
An intense bouquet from planktonic microalgae has also been associated with
fatty acid transformation, mainly halogenated fatty acids and fatty acid-derived
metabolites. Otherwise, fatty acids render long-chain aldehydes (LCA) by means of
5 Volatiles in the Aquatic Marine Ecosystem: Ethylene and Related Plant Hormones…
mones, as Baweja et al. (2009) indicated. Competence is defined as the status in
which a cell must be able to perceive, transduce and respond to a signal (Osborne
and McManus 2005). There was a confused but apparently accepted idea that any
part of any alga was competent with respect to plant growth regulators, but this is
not so (Baweja et al. 2009). All in all, our knowledge of the role of volatiles in algal
reproduction is so little and so disperse but truly incredible to discover.
5.2 Volatile Compounds Are All Around: How Do Algae
Smell?
Very briefly, algae smell of short-chained aromatic volatiles, the most common
components as benzaldehyde, which contribute to the flavour of processed algae
and algae-based products, something of great importance in the industry, since their
identification would determine the quality and freshness of a product as their organoleptic features are related to processed foods (Yamamoto et al. 2014). Other wellcharacterised volatile organic compounds have been identified, such as alkanes,
alkenes, alcohols, terpenes, carbonyls, esters, halogen, compounds containing sulphur and acids (Loreto and Schnitzler 2010; Klaschka and Kolossa-Gehring 2007;
Holopainen 2004; Bleecker 2000).
Halogenated compounds are the most extensively studied volatiles. The production of halomethanes from macroalgae has been reported to vary by up to three
orders of magnitude depending on the geographical location (Schall et al. 1994;
Manley et al. 1992) and by anthropogenic effect (Goodwin et al. 1997).
Specifically, chlorinated compounds have been encountered in algae, in spite of
being relatively rare in living organisms. Their interest lies in their antibacterial
properties, such as the green alga Chara globularis, reportedly emitting against
Staphylococcus aureus (Bankova et al. 2001).
Micro- and macroalgae also contribute to a large extent to the production of bromine and polybromomethanes in marine environments (Paul and Pohnert 2011;
Carpenter et al. 2003), and their presence in the atmosphere may directly affect
human health, cloud condensation nuclei formation and climate (Pirjola et al. 2000).
Moreover, bromine is known to be the halogen often found in marine-derived compounds (Abrahamsson et al. 1995). It is estimated that around 70% of the world’s
bromoform is produced by macroalgae (Carpenter and Liss 2000).
Furthermore, seaweeds also produce other haloforms, whose emission rates
depend on light intensity and pH changes. For example, halomethane production has
been reported in the green algae Enteromorpha and Ulva, in the giant kelp Macrocystis
(Goodwin et al. 1997) and in the brown seaweeds Ascophyllum, Fucus and Laminaria
and in the red seaweeds Gelidium, Asparagopsis, Eucheuma and Mastocarpus
(Garcia-Jimenez et al. 2013; Mtolera et al. 1996 and references herein).
An intense bouquet from planktonic microalgae has also been associated with
fatty acid transformation, mainly halogenated fatty acids and fatty acid-derived
metabolites. Otherwise, fatty acids render long-chain aldehydes (LCA) by means of
5 Volatiles in the Aquatic Marine Ecosystem: Ethylene and Related Plant Hormones…