Download Effects of Climate Change on Aquatic Ecosystems

Effects of Climate
Change on Aquatic
Ecosystems
John Gunn
Canada Research Chair for Stressed Aquatic Systems
How will climate change affect water
quality and quantity in Ontario?
1.
Increased evaporation – leading to lower water levels
(surface and groundwater) – drought
2.
Increased concentration of nutrients and contaminants –
increased algal bloom, bacteria and beach closures
3.
Longer ice free period – increased end of summer anoxia
and macrophyte growth
4.
Changes in time, intensity of precipitation events – winter
thaw, floods , erosion, sewer overflows
5.
Loss of wetlands – release of stored sulphur and metals
Declining lake levels
Declining Ice Cover
January 10, 2007
J. Houle
Extreme Events
Swan Lake Wetland
Millions of tons of stored sulfur in wetland soils: Our 100 year legacy
SO4-2
pH
6.0
5.5
5.0
Drought and Re-acidification of
Swan Lake
4.5
4.0
82 84 86 88 90 92 94 96 98
Year
How will climate change impact
aquatic ecosystems?
1.
Distribution and abundance of fish
2.
Changes in contaminant flux ( Hg)
3.
Changes in nutrient cycling
Kelly Lake
2005 Extreme Temperature
29-30°C
Heat shock mortality in Ontario’s Far North
40
Air Temp. °C
35
30
2001 Daily Maximum
Temperature at Peawanuck
25
20
15
10
5
0
15-Jun
22-Jun
29-Jun
06-Jul
13-Jul
20-Jul
27-Jul
03-Aug
10-Aug
Small mouth bass
invasion in Ontario
Current - Historic [Hg] (ppm)
Temporal change (~ 1979 to 2009) in muscle [Hg] for seven
fish species across northern Ontario lakes (at 1 kg)
0.2
Ontari
o
0.1
0.0
-0.1
WALL
NP
LT
BUR
SMB
LWF
WS
Photo courtesy of Friends of Ramsey Lake
What are invasive species, how are
they getting here, and what types of
impacts do they have?
1.
Non indigenous species ( milfoil) and
expanding native species (smallmouth bass)
2.
Boats, aircraft, intentional human-assisted
introductions, floods, etc.
3.
Increased competition and predation and
often elimination of some native species
Invasive Species
Non-native
Native
E. Engbretson
Borrowman 2010
How will climate change affect
Ontario's overall aquatic
biodiversity? The fishing industry?
1.
Loss of many coldwater species ( lake trout,
brook trout)
2.
Expansion of warmwater species
3.
Decline of commercial and recreational
harvest opportunities for coldwater species
3.5
3.0
2.5
Lake charr CPUE 2.0
(n/net)
77%
1.5
1.0
0.5
0
Reference
(No bass
No roads)
Bass and
Roads
Kaufman et al 2008 CJFAS
What kind of adaptation measures
are there to decrease the risks to
aquatic ecosystems?
1.
Reduce overall water use and the harvest of
vulnerable species
2.
Protect and restoration of key habitat
features – wetlands, riparian and shoreline
buffers
3.
Reduce contaminants and nutrient additions
4.
Eliminate the movement of non native
species
Is this good enough?
Will this work?