Environmental Engineering Reference
In-Depth Information
1999
; Marchand and Rontani
2001
; Rontani
2001
; Lemaire et al.
2002
; Rontani
and Volkman
2003
; Marchand et al.
2005
; Christodoulou et al.
2009
; Christodoulou
et al.
2010
). Chl can also be degraded in higher plants, which for instance causes
the colour change in leaves from green to yellow or red that is naturally observed
in autumn. However, degradation can also occur as a consequence of cell death
caused by external factors, such as injuries due to low or high temperature, pathogen
attack, as well as phenomena taking place during various phases of the life cycle
of plants (Hendry et al.
1987
; Takamiya et al.
2000
). Conversion of Chls to pheo-
phytins can take place during discolouration of green vegetable upon processing
by several chemicals, photoinduced or enzymatic reactions including simultaneous
actions of enzymes, weak acids or changes in pH, oxygen, light and heat (Blair and
Ayres
1943
; Gupte et al.
1964
; Hayakawa and Timbers
1977
; Minguez-Mosquera
et al.
1989
; Mangos and Berger
1997
; Koca et al.
2007
). Moreover, the key PSII
degradation reactions of Chls are photooxidation, involving attack of singlet oxygen
or HO
•
via H
2
O
2
, and enzymatic degradation (Takamiya et al.
2000
; Brown et al.
1991
; Hörtensteiner
2006
; Kräutler and Hörtensteiner
2006
; Moser et al.
2009
;
Hörtensteiner and Kräutler
2011
; Gálvez et al.
1988
).
This chapter will give an overview of the various kinds of Chl, their properties,
functions, and techniques for their precise determination. It extensively discusses the
distribution of Chl
a
providing information about SCM and DCM depths, the forma-
tion mechanisms of such maxima as well as the changes of Chl
a
concentrations
in a variety of natural waters, under both field and experimental conditions. It also
discusses the degradation and degradation mechanisms of Chl
a
bound to aquatic
microorganisms and higher plants, as well as the modifications taking place during
food processing. Finally, an explanation will be provided of how Chl
a
acts as a uni-
versal signature of phytoplankton bloom, and of the possible actions to be adopted
for the management of eutrophication by controlling primary production or Chl
a
.
2 Chlorophylls (Pigments) in Phytoplankton
Photosynthetic organisms can collect light energy with their light-harvesting systems
that are composed of core and peripheral antenna complexes (Green and Durnford
1996
). Core antenna complexes of oxygen-evolving photosynthetic organisms have
Chl
a
as pigment. In contrast peripheral antenna complexes, particularly for photo-
system II (PSII), have various pigments depending on the group of photosynthetic
organisms. They are Chl
b
, Chl
c
(made up of
c
1
,
c
2
and
c
3
), Chl
d
, phycobilins,
fucoxanthin, zeaxanthin (carotenoids), echinenone, peridinin, and so on (Bianchi et
al.
2002
; Woodward et al.
1960
,
1990
; Dougherty et al.
1966
; Fleming
1967
; Wu
and Rebeiz
1985
; Jeffrey and Wright
1987
; Verne-Mismer et al.
1988
,
1990
; Fookes
and Jeffrey
1989
; Rowan
1989
; Grossman et al.
1995
; Miyashita et al.
1996
,
1997
;
Motilva
2008
).
Chl
b
is detected in various forms such as: divinyl Chl
b
, with two vinyl
groups at R
1
and R
2
positions; monovinyl Chl
b
, with vinyl at R
1
and ethyl at
