CMOP_ETM_Initiative_HalfBakedtalk28June2011

Report
I-IV: Physics & Biogeochemistry of Estuarine Turbidity Maxima
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Estuarine Turbidity Maxima (ETM) are major features in both the North and South
Channel of the Columbia River estuary.
Detailed understanding and ability to predict the ETM dynamics is necessary to address
the variability and change of the biogeochemistry and ecosystem function in the lower
Columbia River estuary, under the effects of climate and land/use. Phase 1 focus.
The biogeochemistry of the North and South channel ETMs shows important contrasts,
the understanding of which matters for CMOP II initiatives in the role of lateral bays on
carbon cycle, in estuarine hypoxia/acidification, and in M. rubra blooms. Phase 2 focus.
For numerical models to usefully address ETM biogeochemistry, they need to be skilled
in representing circulation and trapping mechanisms at fine scales. Core CMOP focus.
salinity:
marine
estuarine
freshwater
sandflats
mudflats
sandy, vegetated
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ETM resuspension and settling
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Long-Term Scientific Goals Enabled by the Phase 1 ETM Initiative
To develop highly skilled numerical models that describe key ETM processes,
in particular density structure, sediment trapping, and exchanges with the
ocean and estuarine lateral bays. This will be accomplished by:
• Measuring and characterizing the dominant physical processes that
determine circulation, mixing and trapping in the North Channel, through
a combination of long-term observations at endurance stations and of
intense fortnightly observations in low and high-flow conditions.
• Characterizing the turbulence structure along the North Channel, and
computing eddy coefficients for incorporation in numerical models.
• Rigorously benchmarking numerical models of circulation and sediment
transport against the observed physical structure of the North Channel
ETM, and exploring strategies for model improvements.
• Conducting a “blind evaluation” of the predictive ability of numerical
models to characterize ETMs at the mouth and in the South Channel of
the estuary.
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Phase 1: North Channel Laboratory
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Instrumentation to deploy: In addition to endurance stations
– Bottom node supporting ADV and CTD
– Sigma profiler
– Repeated vertical profiling from R/V, including V, T, S, O2, OBS, LISST 100,
altimeter and turbulence profiles, supplemented by appropriate
biogeochemistry sensors
– Doppler radar measurements of surface velocity over N. Channel
– Mobile profiles of water properties with an autonomous mobile AUV
Field operations (IOP): Two-week operations in May and September 2012
Expected Outcomes:
– Improved understanding of flow and mixing in N. Channel
– Refined parameterizations of bottom and interfacial stresses
– Improved skill of circulation models
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Long-Term Scientific Goals Enabled by the Phase 2 ETM Initiative
Develop and demonstrate detailed quantitative understanding and
predictive ability of how the salinity intrusion and ETM formation
influences biogeochemical factors, and demonstrate portability of
theses predictive capabilities to the South Channel and entrance
ETMs.
• Determine and contrast the dynamics and biogeochemistry of the
three Columbia River ETMs, and their role as bioreactors for
transformation and removal of river-borne nutrients and biogenic
inputs.
• Predict climate change and land-use impacts on Columbia River
ETMs, and integrate acquired understanding on regional efforts
assessing or managing habitat and water quality for fisheries and
aquaculture.
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What is Needed to Achieve ETM Goals and Operations
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• People: Initial team:
– Lead PIs: Tom Sanford and Byron Crump
– Phase 1 PIs: Jim Lerczak (OSU), Murray Levine (OSU), Antonio Baptista (OHSU), Yvette
Spitz (OSU), Craig McNeil (APL-UW), Gordon Farquharson (APL-UW), Fred Prahl (OSU)
• Prior Studies: CRETM-LMER
• Instruments and facilities:
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Endurance stations
R/V Forerunner (scheduling limitations?) and access to UNOLS vessels
PI and CMOP instrumentation and methodologies
CMOP’s Virtual Columbia River modeling
• Funding:
– NSF from CMOP II
– Contributions from involved PIs from personal grants
– Extramural sources, especially for instrumentation
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ETM resuspension and settling
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Particle-attached bacterial production correlates with turbidity
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ETM particles are aggregates, and can be >1mm in size
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Unique ETM bacteria amid allochthonous communities (1997)
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Ocean
River
Estuary
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Diversity correlates with salinity, varies with season, repeats annually
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Fortunato et al. In Prep
Marine Diatoms dominate 18S rRNA sequences in bottom waters.13
Abundant diatom sequences
Salinity
100%
5.9
13.1
10.3
11.8
2.3
2.9
5.4
7.3
12.4
0.9
80%
60%
40%
20%
0%
18.3
Bottom
2.1
Surface
Turbidity (NTU)
Marine diatom
Freshwater diatom
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Conceptual model of OM composition in Estuary
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Estuary particulate organic matter
refractory = freshwater diatoms
labile = freshwater diatoms
labile = marine diatoms
labile = estuary M. rubra bloom decay
labile = estuary retention of Katablepharis
salinity
5.9
river flow
River
Ocean
salinity = 0.9
12.4
13.1
tidal flow
post
ETM
peak
ETM
pre
ETM
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