UWs Burke Museum

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UWs Burke Museum
and..at a theater near you Arctic Tale Winged
Migration, Never Cry Wolf, Fast Runner, Snow
Walker
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Lec 6 Estuaries another kind of conveyor belt
circulation
HAS221a 2008 Oceans and the global environment
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Near the coasts oceanic phytoplankton can be
intensely productive, as in these images of
(false) ocean colorredis high chlorophyll, high
phytoplankton
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• Estuaries where rivers meet the sea
• some of which are fjords, which are carved by
  glaciers
• San Francisco Bay, Chesapeake Bay, Puget Sound,
  Boston Harbor, Cook Inlet and numerous rivers
  (e.g. Columbia River WA, Fraser River, BC Canada)
  
• Estuaries provide roughly 75 of the US fish
  catch (value 111B per year)

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problems

• overenrichment of nutrients gt oxygen depletion
  (e.g. Chesapeake Bay, Hood Canel on Puget
  Sound)
• pathogen contamination virus, bacteria,
  parasites gt shellfish bed closures
• toxic chemicals (heavy metals, pcbs, aromatic
  hydrocarbons..)
• alteration of freshwater inflow (as well as
  natural seasonal cycles) usually by new
  construction houses, highways
• loss of habitat
• declines in fish and wildlife (e.g. Delaware
  horseshoe crab scallops in New York)
• and introduction of invasive species (e.g., San
  Francisco Bay, Asian clams dominate, and filter
  the entire water body every few hoursplankton
  and all)

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Dissolved oxygen

• 5 to 6 parts per million, close to saturation, is
  healthy. Where oxygen concentration is less than
  2 parts per million, it is known as hypoxia
  danger to fish, shellfish
• Excess algae shade the water of sunlight, and
  when they decay, use up oxygen
• In Maryland Coastal Bays runoff from land
  contributes more than 50 percent of nitrogen
  loadings. Half of these loadings are associated
  with agricultural feeding operations (primarily
  poultry), despite the small amount of land area
  occupied by these operations
• http//www.epa.gov/owow/estuaries/

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Segar, Introduction to Ocean Sciences
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http//green.kingcounty.gov/WLR/Waterres/hydrology
/GaugeMap.aspx
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Segar, 2007 text
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http//geosci.sfsu.edu/courses/geol103/labs/estuar
ies/partI.html
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RECREATIONAL CRAB HARVESTMarine Area 9 -
Admiralty Inlet
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red tide (harmful algal bloom) California coast
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http//www.nwfsc.noaa.gov/hab/outreach/videos/ecoh
abpnw4.html
The Juan de Fuca eddy traps domoic acid, which
causes harmful algal blooms when it migrates in
to shore
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John Mickett Mark Warner UW Oceanography
anoxic water in Hood Canal (the blue region near
the end of the canal)
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average dissolved oxygen concentration in the
water below 20 meters depth in the region between
Dabob Bay and the Great Bend (PRISM Station 11)
plotted versus the day of the year
2003 to 2006 oxygen concentration in Hood Canal
(Sund Rock) dangerously low
diseased krill zooplankton
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• salmon recovery 600 mile of stream banks
  restored
• fish-friendly dams, some dam removal
• increased protection for 60,000 miles of streams

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Admiralty Inlet where the Pacific Ocean salty
water cascades down over a sill into the main
basin of Puget Sound to the South. From the air
you can see streaks indicating this flow.
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lab model of the conveyor belt circulation in an
estuary
open ocean

river input
Parker MacCready, UW Oceanography
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The estuary is a conveyor belt circulation driven
by the buoyancy difference between the fresh
river water and 3 salinity of the open ocean.
However if the river flowed quietly in on top of
the ocean water, no such circulation would
develop. The tides stir the fresh water down,
making it available to drive the overturning
conveyor belt. The circulation that results is
typically 15 to 50 times as big (in volume flow)
as the river flow itself.
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Puget Sound is a basin with relatively shallow
connection with the Pacific Ocean. Despite its
complexity, it does function as the kind of ideal
estuary we described above tides stir the fresh
river runoff down into the salty water below,
thus creating a massive conveyor belt circulation
that brings in ocean nutrients and helps to keep
the subsurface water healthyexcept for isolated
branches like Hood Canal
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The case of cholora Peru and Bangladesh

• Vibrio cholorae lives in coastal oceans,
  attaches to shellfish..here a copepod. Like
  hurricanes, it is sensitive to upper ocean
  temperatures. Massive outbreaks of cholera occur
  where poor public health
• practices (sanitation) combine with a source of
  the pathogen

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ocean temperaturefrom satellite
cholera cases ocean temperature in
Bangladesh
1992
1995