Transcript Trends in sea surface temperature (1890 - 2007)

Variability in the physical structure,
ocean chemistry, plankton ecology and
commercial fish species of the seas
surrounding Ireland between 1997 and
2010
G. Nolan 1, K.Lyons1, S.Fennell1, T. Mc Grath1,
D.Guihen2, C.Cusack1, C. Lynam3
ICES/NAFO Decadal Symposium, Santander
11th May 2011
19/04/07
Water mass overview
May 2011
Biogeographical provinces:
Niall Mc Ginty et al., (Poster 78)
Trends in sea surface temperature (1890 - 2007)
Local temperature anomalies extracted from HadSST2. Malin head data
is overlain in red (Note apparent 60 year cycle in N. Atlantic)
Recent intense warming in the NE Atlantic attributed
in part to the AMO (Atlantic Multidecadal Oscillation),
and in part to global warming.
Sub-polar gyre cooled over the 1955-2003 period,
consistent with predominantly positive NAO
Cannaby H, Husrevoglu YS (2009) The influence of low-frequency variability and long-term
trends in North Atlantic sea surface temperature on Irish waters. ICES J Mar Sci:fsp062
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AVHRR: SST anomaly from 1985-2006 mean
Stn 16 2007/ stn 13 2008 / stn 12 2009
Porcupine Bank
Station depth
= 3000m
-500
SAIW
2010
MEDW
2007
-1000
-1500
-2000
-2500
-3000
34.8
35
35.2
35.4
Red:2006, Green: 2007: Blue: 2008, Black: 2009, Purple 2010, Yellow 2011
35.5
-240
-250
Apr08
Jul08
Oct08
Jan09
Apr09
Jul09
Oct09
35.5
-480
-500
Apr08
Jul08
Oct08
Jan09
Apr09
Jul09
Oct09
-950
-1000
-1050
Apr08
35
35.5
-700
-750
Apr08
35
Jul08
Oct08
Jan09
Apr09
Jul09
Oct09
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35.5
Jul08
Oct08
Jan09
Apr09
Jul09
Oct09
35
19/04/07
Spring Bloom timing
Development of suitable
growth conditions in Spring
using SST as an indicator
Timing of Spring in Julian Days
JD of Spring arrival (10 °C)
163
05 June
156
2: General Trend in coastal waters
that it is arriving earlier
Julian Day
149
142
135
128
3: Abiotic conditions important in
spring (water column structure and
nutrient availability)
121
114
107
100
1950
1: Interannual variations on the
date SST reaches 10 C
1960
1970
1980
1990
2000
2010
Year
2006-2007 Winter:
Land vegetation greening occurred 10
days earlier than the average over the
past three decades
(Geophs. Res. Lett. 2008) Maignan et al.
15 April
1959 – 2005
(47 years daily SST data).
Phytoplankton colour and HAB
species
AMO
Phyto Colour Index
Positive
2
4
6
8
% samples K. mikimotoi present
10 12
2005
2005
2000
2000
1995
1995
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9 10 11 12
2005
2000
1990
1990
Negative
% samples
1985
1985
1980
1980
1975
1975
50 to 100
25 to 50
10 to 25
5 to 10
1 to 5
0 to 0
1995
1990
PCI (RU)
1970
1970
1965
1965
1960
1960
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10
0.0 to 0.2
0.2 to 0.5
0.5 to 1.0
1.0 to 2.0
2.0 to 3.0
3.0 to 4.0
4.0 to 5.0
5.0 to 6.5
12
Month
An increase in phytoplankton biomass is
evident in the northern Celtic Sea, based
on Continuous Plankton Recorder (CPR)
data, since 2000
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The percentage occurrence of Karenia mikimotoi
during the winter months has increased since 2000
Total annual abundance of harmful and toxic species
varies greatly between years
Warm >>>>>>>>>> cold
Zooplankton changes:
Beaugrand view of whole
region
Specific look at warm water
species in Irish waters
(on the increase)
mean abundance in Celtic Sea :
Annual
March
p < 0.05
The abundance of a common warm
water species (Calanus helgolandicus)
has increased to the southeast of
Ireland
Poor cod distributions 2003/4 vs 2006/7
(possible indicator species)
Poor cod and lesser spotted dogfish have increased to the north of Ireland
and decreased to the south and are suitable candidate climate indicator
species
Decline in cold-water species
of fish and increase in warmwater species (Kendall tau
plot) eg. Boarfish
Fishery effects must be considered and
long-term data is required to detect such
change
Red= expected distribution Blue= actual
Pipefishes (Syngnthidae) – related to seahorses
A symptom of major ecosystem changes?
60°0'0"N
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Possibly linked to SST rises?
Largely absent from samples
1958-2001 Increase in catch in
2003, 2004, 2005
Migratory fish species
Salmon –
Adult salmon
declining marine survival
since the 1970s
No. returns to trap
2000
1500
1000
500
0
1965
1985
2005
Time (years)
Sea trout –
Sea trout
Survival (%)
50
stock collapse in 1980s, with adult
returns still at a low level
25
0
1965
1985
Tim e (years)
2005
Nutrient analysis: water mass definition
Higher phosphate values
on WOCE cruises
AABW
signal
Higher surface nutrients
in more recent cruises
May 2011
Conclusions
1. Warming trend with AMO signal apparent at
2.
3.
4.
5.
6.
7.
Malin Head
LSW (freshened between 2004 and 2009 and
then increased salinity in 2010 and 2011)
Changes in temperature are mirrored in biological
data sets
Increases in the annual numerical abundance of
diatoms and dinoflagellates are evident in all
coastal regions since 1998.
Warm water fish species more prevalent
Decline in migratory fish returns
Some differences in nutrient concentrations when
comparing WOCE data with 2008-2010 data