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And our future
Presentation by
Thomas Neudorfer
Puget Sound Watershed
•Puget Sound has 2100+ miles of shorelines
• The canal is shallow at the entrance… very deep along the long arm…. and becomes considerably shallow again within the short arm
• The region was ‘carved’ out by the most recent glacial retreat nearly 13,000 years ago.
•The glacial activity created a long, L-shaped, like body of water
• Hood Canal is about 60 mile long with nearly 200 miles of shoreline
U.S. Coastal ‘Dead Zones’ Associated with Human Activity
National attention in 2003
Pew Ocean Commission report June, 2003
The Hood Canal Dissolved Oxygen Program (HCDOP) is a collaborative effort between many parties to study and model the canal in order to recommend corrective actions and, in parallel, to direct effort towards education and early potential corrective actions.
Southern Hood Canal (Dabob Bay to Great Bend)
Average Dissolved Oxygen Measurements (below 20m) – 1950s - 2004
Low oxygen conditions appear to be getting worse. The 2004 inventory of the oxygen is the lowest on record.
RESULT: Hood Canal is naturally predisposed to low dissolved oxygen, much more so than Puget Sound which is better flushed and less stratified.
Hood Canal Attributes
Strong stratification, distinct layers maintained with different characteristics.› Deep waters with low oxygen don’t get mixed.
Slow circulation, long residence time.› Bulk of waters are “old” – with no recent air
contact.
High productivity, high organic load.› Oxygen is respired away during decomposition
of this matter.
Where is Dissolved Oxygen a Problem?
Oxygen concentration and marine life…
bad
real bad
good
OK
anoxic…no oxygen
real bad…
…throughout year
The lower portion of the canal suffers from low DO levels for most of the year.
HCDOP Integrated Assessment and Modeling
Science Plan
Marine Water Monitoring Utilize profiling moorings and nearshore transects to measure circulation and water quality
Fresh Water Flow & Nutrient Loading Monitor flow and water quality in rivers, streams, groundwater and map associated land use
Marine Life Studies
Assess DO effect on biota and biota effect on DO
Modeling and Analysis Develop and verify computer models of marine and terrestrial system, run scenarios and corrective action analysis
Rapid Response & Diver Program Respond to fish kills and algal blooms, maintain diver observation records
A multi-disciplined science plan (IAM) has been formed by multiple stakeholders to better understand Hood Canal oxygen variation.
http://www.hoodcanal.washington.edu
Increased Nutrients: Nitrogen
• Essential for life• But can be harmful at high levels• Increased human development
Increased levels of nitrogen enter Hood Canal
watershed
WARM
COLD
temperature salinity determine density
FRESH
SALTY
+
less dense
more dense
Stratification: persistent
Stratification gets even stronger in the summer and fall
Low nutrient High oxygen
High nutrient Low oxygen
Organic (primary) production:
Phytoplankton Sinks And Decays (decay uses up oxygen and leaves nutrients)
{ CO2 + H2O C(H2O) + O2 }
sunlight nutrients
Respiration
Photosynthesis
High production and respiration
Phytoplankton Grows(growth uses up nutrients and creates oxygen)
More Humans = More Nutrients
Phytoplankton Grows More Rapidly
(uses additional nutrients and creates oxygen)
Additional nutrients (plant food)
Low oxygen…
…can get lower Nutrient additions from human activity can
make the low dissolved oxygen problem worse.
More organic material to sink and decompose
Dense (colder, salty) ocean water
Dense (colder, salty) ocean water
Light (warmer, fresher) canal/river water
Intermediate (warming, freshening) water
Hood Canal bridge area Big Bend areaN
Slow Circulation = Poor Flushing
Ocean Input
River Inputs
**
*
* *Change ocean input:
O2, density
Change river input:
flushing, stratification
Change light availability:
more sun
Change organic biomass/prod’n:
better growing conditions, carcass loads
Change nutrient availability:
septics, forest, runoff loads
To what degree each of these processes is driving the oxygen variation in Hood Canal is not known
Sources: DOE , HCDOP, EPA, PSP, HCOW.GOV, PEW, ECY.GOV
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