Geoscience Reference
In-Depth Information
Table 6.4
Effects of ocean acidii cation on calcii cation in planktonic organisms, comparing rates at pre-industrial/present-day p CO
2
levels with those
at p CO
2
projected for the end of this century.
Group/species
Response References
Foraminifera
¯
Lombard et al. ( 2010 )
Pteropods
¯
Comeau et al. ( 2009 )
Echinoderm larvae
¯
Clark et al. ( 2009 ), Sheppard Brennand et al. ( 2010 )
Coccolithophores
Emiliania huxleyi
Calcii cation
Iglesias-Rodriguez et al . ( 2008 ), Shi et al . ( 2009 )
¯
Riebesell et al. ( 2000 ), Zondervan et al. ( 2002 ), Sciandra et al. ( 2003 ), Delille et al. (2005),
Engel et al. ( 2005 ), Langer et al. ( 2006 ), Feng et al. ( 2008 ), Gao et al. 2009 , De Bodt et al.
( 2010 ), Hoppe et al. (pers. comm.)
«
Buitenhuis et al. ( 1999 )
PIC:POC
¯
Buitenhuis et al. ( 1999 ), Riebesell et al. ( 2000 ), Zondervan et al. ( 2002 ), Delille et al. (2005),
Engel et al. ( 2005 ), Langer et al. ( 2006 , 2009 ), Feng et al. ( 2008 ), Iglesias-Rodriguez et al.
( 2008 ), Gao et al. ( 2009 ), Shi et al. ( 2009 ), De Bodt et al. ( 2010 ), Müller et al. ( 2010 ), Hoppe
et al. (pers. comm.)
«
Sciandra et al . ( 2003 ), Langer et al. ( 2009 )
Gephyrocapsa oceanica
Calcii cation
¯
Riebesell et al. ( 2000 )
«
Rickaby et al. ( 2010 )
PIC:POC
¯
Riebesell et al. ( 2000 ), Rickaby et al. ( 2010 )
Calcidiscus leptoporus
Calcii cation
¯
Langer et al. ( 2006 )
PIC:POC
¯
Langer et al. ( 2006 )
Coccolithus pelagicus/
braarudii
Calcii cation
¯
Müller et al. ( 2010 )
«
Langer et al. ( 2006 ), Rickaby et al. ( 2010 )
PIC:POC
¯
Müller et al. ( 2010 )
«
Langer et al. ( 2006 ), Rickaby et al. ( 2010 )
, enhanced;
¯
, slowed down;
«
, unaffected/inconclusive.
PIC, particulate inorganic carbon; POC, particulate organic carbon.
be replaced by other groups and/or more CO
2
/pH-
tolerant calcifying species. It is also unknown
whether adaptation will allow calcii ers to overcome
the adverse effects of ocean acidii cation.
no effect of elevated
p
CO
2
. A diverse set of responses
is seen in diatoms, which in some cases show oppo-
site trends even in closely related species (e.g.
Burkhardt
et al.
1999 ).
A trend towards higher C:N and C:P ratios also
emerges from studies on natural phytoplankton
assemblages in mesocosm CO
2
perturbation stud-
ies, as observed in suspended particulate organic
matter (POM) (Engel
et al.
2005 ), in the drawdown
of dissolved inorganic carbon relative to nitro-
gen (Riebesell
et al.
2007 ; Bellerby
et al.
2008 ), and
in sedimented organic matter (Schulz
et al.
2008 ).
No effect of CO
2
on natural community C:N ratios
was observed by Kim
et al.
( 2006 ) or Feng
et al.
(2008). In contrast, no consistent response was
obtained for N:P ratios (Tortell
et al.
2002 ; Engel
et al.
2005; Bellerby
et al.
2008 ; Feng
et al.
2010 ) . Elevated
CO
2
has also been observed leading to enhanced
production of extracellular organic matter (Engel
6.3.5 Cell stoichiometry
In view of the multiple effects of ocean acidii cation
on key metabolic processes such as carbon and
nitrogen i xation, respiration, and calcii cation, it is
not surprising to also i nd strong changes in the
chemical composition of primary producers with
changing carbonate chemistry (see Hutchins
et al.
2009 for a detailed review). A common response to
elevated
p
CO
2
is an increase in cellular carbon to
nitrogen ratios (Table 6.5). A comparatively uniform
response in this respect is obtained for coccolitho-
phores and cyanobacteria, which with few excep-
tions either show increased C:N and N:P ratios or
