Transcript PPT - US Globec

US GLOBEC
Fundamental Discoveries and Surprises
David Mountain
How to Choose?
Fundamental discoveries or findings
- integrative, bigger picture
Surprises
- big, small … whatever…
Apologies
Northwest Atlantic
Salinity anomaly
Low salinity in 1990s – particularly during GLOBEC
Northwest Atlantic
Gulf of
Maine
Salinity anomaly
Phytoplankton –
seasonal timing/abundance
Zooplankton –
community structure
Cod & Haddock early life survival
consistent with stock abundance
Georges
Bank
So where did the low salinity come from?
In flow from Scotian Shelf
Gulf of St. Law & north
Arctic outflow
So where did the low salinity come from?
In flow from Scotian Shelf
Gulf of St. Law & north
Arctic outflow
Ecosystem changes are driven by external advection
And the response of the internal system dynamics to that forcing
Multi-decade simulation captures system variability
Response to large-scale atmospheric forcing
changing the amount and source of upwelling
High NPGO – upwelling from deeper depths
(higher nutrients, lower O2)
(Di Lorenzo et al., 2008)
Zooplankton:
Community changes caused by
horizontal advection associated with
that same forcing (PDO variability)
(Keister et al., 2011)
Zooplankton:
Community changes caused by
horizontal advection associated with
that same forcing (PDO variability)
(Keister et al., 2011)
Ecosystem changes are driven by external advection (vertical and horizontal)
And the response of the internal system dynamics to that forcing
Coastal Gulf of Alaska
Cross-shelf gradients in factors
controlling production
LNHC
Macro- vs micro- nutrients
Large vs small phytoplankton
Large vs small micro-zoo
Large vs small copepods
HNLC
Different dynamics over short distances
Single quantitative framework (…model…) needs all of
the above to represent both regions simultaneously
(Hinckley et al., 2009)
Coastal Gulf of Alaska
Cross-shelf gradients in factors
controlling production
Macro- vs micro- nutrients,
Large vs small phytoplankton ,
Large vs small micro-zoo
Large vs small copepods
LNHC
HNLC
Different dynamics over short distances
climate
likely will(…model…)
influence these
regions differently
SingleChanging
quantitative
framework
to represent
with
different implications
populations
both regions
simultaneously
needs allfor
ofthe
thelocal
above
Southern Ocean
Winter krill concentration
2001
Onset of winter ice coverage
2001 - Late
2002 - Early
Cold temperatures in 2002
2002
Low winter krill survival in 2001
- low ice algae concentrations
(Lawson et al., 2008)
Southern Ocean
Biological ‘Hot Spots’
Regions where predators concentrate
bathymetric, physical and biological
conditions combine to provide
consistent source of prey
Influx of Circumpolar Deep Water
- heat, nutrients
higher PP
- ties to the ACC
(Pinones et al., 2011)
Southern Ocean
Biological ‘Hot Spots’
Regions where predators concentrate
bathymetric, physical and biological
conditions combine to provide
consistent source of prey
Influx of Circumpolar Deep Water
- heat, nutrients
higher PP
- ties to the ACC
Ecosystem sensitive to climate change affecting both local atmospheric
forcing and external advection associated with the ACC
Surprises
3 flavors:
- Unexpected
- Assumed but didn’t find
- Assumed and found
Unexpected
Northwest Atlantic
In 1990s
Haddock early survival increased by x4
Cod early survival decreased by x4
And stock abundance changed similarly
Fishery management to get some credit,
but significant ecosystem component
controlling change in stock abundance
Unexpected
California Current System
Low dissolved oxygen
Oregon shelf (2002 obs)
CALCOFI region (retrospective)
Temporal trend of lower oxygen
- adverse biological effects
Upwelling of deeper, offshore waters
(lower O2 and higher nutrients)
associated with higher NPGO/lower PDO
Shoaling of hypoxic boundary
1984-2006
(Bograd et al., 2008)
Unexpected
California Current System
Delayed upwelling in 2005 –
Poor survival/condition for salmon
and other organisms
(major economic consequences)
Unexpected
California Current System
Delayed upwelling in 2005 –
Poor survival/condition for salmon
and other organisms
(major economic consequences)
Timing Matters
Expected but didn’t find:
Northeast Pacific
Expected inverse salmon
production in CGOA and CCS –
split of west wind drift
Not found – other factors dominant
in that variability
Assumed and found
Species Matter
Species specific characteristics (e.g., behavior, nutrition)
necessary to explain observations
Assumed and found
Species Matter
Species specific characteristics (e.g., behavior, nutrition)
necessary to explain observations
Its not just total carbon (or other currency)
Species Matter
Summary:
Identified major pathways through which
climate change will influence these ecosystems
and
the internal phy/bio dynamics controlling the
system response to that forcing
Summary
Identified major pathways through which
climate change will influence these ecosystems
and
the internal phy/bio dynamics controlling the
system response to that forcing
GLOBEC!
But history and experience caution humility
These are large, complicated ecosystems
We have learned a lot
But history and experience caution humility
These are large, complicated ecosystems
We have learned a lot
… so the new generation of researchers
need have no fear of running out of new,
fundamental discoveries to be made.
End