Environmental Engineering Reference
In-Depth Information
climate warming (Vinebrooke and Leavitt
1998
; Schindler et al.
1996
; Yan et al.
1996
; Sommaruga et al.
1999b
). UV-B radiation strongly influences aquatic car-
bon, nitrogen, sulfur and metals cycles and affects a wide range of life processes
(Epp et al.
2007
). UV-B radiation changes the biological availability of dissolved
organic matter (DOM) to microorganisms and accelerates DOM transformation
into dissolved inorganic carbon and nitrogen, including carbon dioxide and ammo-
nium (Epp et al.
2007
). It is reported that large shifts in underwater UV-B, UV-A
and photosynthetically available radiation (PAR) associated with changes in the
input of colored DOM occurred into subarctic lakes during the Holocene (Pienitz
and Vincent
2000
). A moderate increase in UV-B also occurred in the northern
hemisphere such as in the Arctic (von Der Gathen et al.
1995
) and in the Swiss
Alps (Blumthaler and Ambach
1990
).
Global warming induces changes of climate, soil and water ecosystems
(IPCC
2007a
). Some 70 % of the Earth surface is covered by water containing an
extremely complicated milieu of organic and inorganic chemical species (Erickson
Iii et al.
2000
). The photoinduced production and transformation of various green-
house and chemically reactive gases in the ocean has been a focus of many studies
over the last century (Erickson Iii et al.
2000
). Increased UV radiation has impli-
cations on the biogeochemistry of the aquatic and marine boundary layer, with
a focus on trace gases such as CO
2
, DMS, CO, OCS, CH
4
, N
2
O, non-methane
hydrocarbons (NMHCs) and organohalogens, which can be exchanged between
the ocean and the atmosphere (Erickson Iii et al.
2000
).
This chapter describes a general overview on the contributions to global warm-
ing of atmospheric constituents including GHGs, as well as their key emission
processes. The aim of this review is to explain the impacts of global warming on
the aquatic biogeochemical processes, including changes in light cycle and water
temperature, photoinduced processes, microbial processes, photosynthesis, pri-
mary production, dissolved organic matter (DOM) dynamics and global carbon
cycle, and finally the nutrients cycle in natural waters. This chapter also discusses
a conceptual model for the effect of global warming on key biogeochemical pro-
cesses and remedial measures for controlling algal blooms caused by global
warming.
2 Global Warming
The atmospheric constituents accountable for global warming are: water vapor;
clouds (condensed water in ice and liquid form); greenhouse gases (GHGs) such
as carbon dioxide (CO
2
), methane (CH
4
), nitrous oxide (N
2
O) and halocarbons
including chloroflurocarbons (CFCs), hydrofluorocarbons (HFCs), perfluorocar-
bons (PFCs), ozone, sulphur hexafluoride (SF
6
), methyl chloroform (CH
3
CCl
3
)
and carbon tetrachloride (CCl
4
) (Wigley
1988
,
1989
; Charlson et al.
1989
; Fisher
et al.
1990
; den Elzen et al.
1992
; Kroeze and Reijnders
1992
; Solomon and
Daniel
1996
; Kiehl and Trenberth
1997
; Quaas et al.
2004
; IPCC
2007a
; Velders
