Spatial and temporal patterns in food web accumulation of by jxp20641

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									Spatial and temporal patterns in food
      web accumulation of Hg

  San Francisco Mercury Coordination Meeting
              February 20, 2008
       Questions addressed
•   Spatial patterns: Where is most
    bioavailable mercury in the Bay?
    – Using small fish as biosentinels
    – Comparing with sediment MeHg data
    – Regions
    – Habitat types and conditions
•   Temporal patterns: How does mercury
    vary in small fish from year to year?
Spatial patterns: Bay margins vs. open waters
                          Spatial patterns: Bay margins vs. open waters
                0.4




                0.1                                                          ARROW GOBY
                                                                             CHEEKSPOT GOBY
                                                                             MISSISSIPPI SILVERSIDE
Hg (g/g wet)




                                                                             SHIMOFURI GOBY
                                                                             TOPSMELT
                                                                             YELLOWFIN GOBY
                                                                             BAY GOBY
                                                                             STRIPED BASS
                                                                             NORTHERN ANCHOVY
                                                                             PACIFIC HERRING
          0.01




      0.003
                      0     20     40          60           80   100   120

                                        Total Length (mm)
                          Spatial patterns: Organized by species habits

                                                      Wetlands/margins
                0.4




                0.1                                                          ARROW GOBY
                                                                             CHEEKSPOT GOBY
                                                                             MISSISSIPPI SILVERSIDE
Hg (g/g wet)




                                                                             SHIMOFURI GOBY
                                                                             TOPSMELT
                                                                             YELLOWFIN GOBY
                                                                             BAY GOBY
                                                                             STRIPED BASS
                                                                             NORTHERN ANCHOVY
                                                                             PACIFIC HERRING
          0.01




      0.003
                                                       Open waters
                      0     20     40          60           80   100   120

                                        Total Length (mm)
             Spatial patterns: Regional patterns across Bay
        Mississippi silverside 2005                                                         Mississippi Silverside 2006
                                      0.2

                                                                                                                          0.18




                                                             Hg wet weight (g/g)
                                                                                                                          0.16

                                      0.15
                                                                                                                          0.14




                                             Hg (ug/g wet)




                                                                                                                                 Hg (ug/g wet)
                                                                                                                          0.12


                                                                                                                          0.1
                                      0.1

                                                                                                                          0.08


                                                                                                                          0.06
0   Miles     20
                                      0.05                   0                      Miles         20
                                                                                                                          0.04




• 2005 elevated in                                                             2006  elevated in Pt.
  southern stations                                                            Isabel (significant)
  (significant)
Spatial patterns including salt pond data




                Includes data provided by C. Eagles-Smith and J. Ackerman
            Topsmelt 2005                                         Topsmelt 2006
                            0.048

                            0.046                                                 0.055

                            0.044
                                                                                  0.05
                            0.042

                            0.04                                                  0.045




                                    Hg (ug/g wet)
                            0.038
                                                                                  0.04
                            0.036
                                                                                  0.035
                            0.034

                            0.032                                                 0.03

                            0.03
                                                                                  0.025
0   Miles   20              0.028                   0     Miles   20




    • 2005 elevated in                                  2006   elevated in
      southern stations                                 southern stations,
      (not significant)                                 Pt. Isabel, and
                                                        Richardson Bay
                                                        (significant)
• Potential
  explanations for
  spatial patterns:
   – High sediment
     MeHg in southern
     stations,
     Richardson Bay
   – Suggests linkage:
     fish vs. sediment
     MeHg
   – Suggests spatial
     gradient




  Source: RMP
                Sediment MeHg may be correlated with
                           topsmelt Hg
                    0.08
                    0.07                                            •Topsmelt 2006 data
                    0.06
                                                                    •RMP and Calfed
Hg in fish (ug/g)




                    0.05
                                                                    sediment data within
                    0.04                                            1.5 km disk of fish

                    0.03                                            •R2 = 0.61


                    0.02

                                   0.5    1.0   1.5 2.0 2.53.0 .5
                                                              3
                           MeHg in sediment (ng/g)
Sediment MeHg higher in shallow/nearshore sites
             38.2

             38.1
                                                Sediment MeHg:
             38.0                                   < 1 ng/g
                                                    1 – 2 ng/g
             37.9                                   > 2 ng/g
  Latitude




             37.8

             37.7
                                                     LOGMEHG
             37.6                                     2
                                                      1
                                                      0
             37.5                                     -1
                                                      -2
             37.4                                     -3
              -122.6   -122.3      -122.0   -121.7
                           Longitude
                                                                 Sediment MeHg Hotspots
         MeHg Hotspots in Sediment
                                                         8000




                   Distance From Nearest Shoreline (m)
                                                         7000                            < 2 ng/g
Concentrations                                           6000
highest close                                                                            > 2 ng/g
                                                         5000
to shoreline and                                         4000
surrounded                                               3000
by land
                                                         2000

                                                         1000




                                                                             0.2 0.4 0.6 0.8 1.0
                                                                Proportion Land Within 2 KM Buffer
  Hypothesis: Importance of enclosed
areas like Pt. Isabel and Richardson Bay
Temporal Patterns
       How Hg varies from year to year?
            Mississippi silverside
       0.3




       0.2
HGWW




       0.1

                                                  YEAR
                                                   2005
       0.0                                         2006
                 SL     NP
                          K      NA   EN
                                        L    SL
             AL
                V             HI            W
                      BE    C       ED    NE

•Station effect    STATION
•Year effect
•Interaction term not significant
•Disconnect from patterns seen in Delta/Suisun Bay (Slotton et al.)
                                   Topsmelt
       0.08

       0.07

       0.06
HGWW




       0.05

       0.04

       0.03                                         YEAR
                                                     2005
       0.02                                          2006
                   L       I       L
                VS       RD      EN     SL    HE
                                                A
              AL       BI      ED
                                       W
                                     NE    OM

•Station effect      STATION
•Year effect
•Similar to Slotton et al.
                       2006 higher than 2005!
Relative importance of station vs.
           year effect


      Species          Station R2 Year R2 Station/Year
      Topsmelt            0.30     0.43        0.7
Mississippi Silverside    0.58     0.05       11.6
                Summary
New   • Interannual variation differs among species
        (habitat types)
      • Elevated in some salt ponds
      • Apparent association between sediment and
        biosentinel MeHg

Q1    • Hg entering food web at Bay margins,
        tributaries, wetlands, salt ponds
      • South Bay and nearshore or enclosed hotspots
        (Pt. Isabel, Richardson Bay)

Q2    • Sediment net methylation may be locally
        important process for food web accumulation
Next step: more intensive survey
• Spatial survey of about 40 stations/yr
(3 years)
• Annual monitoring at 8 stations to determine
  trends
• Monthly monitoring at 2 stations to determine
  seasonal variation
• External collaborations
  – Combining efforts with UC Davis team
  – Diffusive Gradient in Thinfilm Devices, Bivalves
    (Hintelmann and Best)
  – Stable Hg isotopes in fish (Blum)
Collaboration/Data Sharing…   Field/Lab Work and Site Access…
Andy Jahn                     Katie Harrold
Mark Sandheinrich             Aroon Melwani
Kristen Cayce                 John Oram
Collin Eagles-Smith           Carrie Austin
Josh Ackerman                 Max Delaney
Wes Heim                      Fred Hetzel
SF Bay Regional Board         Richard Looker
                              April Robinson
                              Meg Sedlak
                              SF Bay National Wildlife Refuge
                              USFWS Stockton
                              USGS BRD
                              California State Parks
                              CA Department Fish & Game
                              Interagency Ecological Program
SUPPORTING INFORMATION:
               Spatial survey
•   Targeting 40 locations
•   Multiple interrelated factors
    A.   Land use, land cover, and Hg sources
    B.   Spatial location in Bay
    C.   Subtidal hydrology and bathymetry
    D.   Sediment physical and chemical
         parameters
    Workplan: Specific questions to
               address
1. Where is mercury entering the Bay food web?
2. What habitats, conditions, or factors help to identify
   hotspots of food web accumulation in Bay margins?
3. Are there interannual trends in MeHg
   bioaccumulation resulting from wetland and margin
   restoration activities?
4. What are the best biomonitoring tools for
   characterizing hotspots of MeHg bioaccumulation?
        Spatial survey potential design
     • Focus on four types of location – test hypothesis of
       effect
     • Include spatial gradient from North to South Bay
     • Also consider subtidal bathymetery/hydrology
     • Focus on topsmelt and Mississippi silverside
Land Use/Land Cover                      N Bay       S Bay
Wetlands                                 5 sites     5 sites
Urban outfall                            5 sites     5 sites
POTW into slough/marsh                   5 sites     5 sites
Control (upland, residential, no
                                         5 sites     5 sites
discharges)
Potential sampling locations –
• E.g., POTW outfalls:
  – Fairfield-Suisun
  – Palo Alto
  – Sunnyvale
  – San Jose
       Coordinate with SBMP sites:
Improve understanding of wetland – Bay linkages




       Topsmelt
       Silversides
                                     Marsh fish
                                     Brine flies
                                     Song sparrows
                          Trend analysis – a multiple
                             station BACI design
                          0.3


                         0.25
Mercury Concentrations




                          0.2                                          Control 1

                                                                       Impact 1

                                                                       Control 2
                         0.15
                                                                       Impact 2

                                                                       Control 3
                          0.1                                          Impact 3

                                                                       Control 4

                                                                       Impact 4
                         0.05


                           0
                                1   2   3   4   5      6   7   8   9

                                                Year
Trend Sampling Locations
 Hamilton
                                Benicia Park
    China
    Camp


                                           Control
                       Point Isabel         Impact (Restoration)




                              Oakland Middle Harbor
      Candlestick
            Point

                                      Eden Landing


            Bird Island/
     Steinberger Slough
                                           Newark Slough

                                             Alviso Slough
Trend Sampling Locations
 Hamilton
                                Benicia Park
    China
    Camp


                                           Control
                       Point Isabel         Impact (Restoration)




                              Oakland Middle Harbor
      Candlestick
            Point

                                      Eden Landing


            Bird Island/
     Steinberger Slough
                                           Newark Slough

                                             Alviso Slough
Monthly sampling locations


       Additional North Bay Station
       Sampled by USFWS




                     Martin Luther King Shoreline
MLK Shoreline Location
 Collection of additional parameters

• Aimed at better understanding
  mechanisms for spatial variation in
  bioavailable Hg
• GIS spatial parameters
• Sediment parameters
               GIS spatial parameters
Parameter Type                        Hypothesized mechanism of influence
Water residence time                  Water dilution and replacement and sediment advective
                                         transport may cause net loss of Hg or MeHg, and
                                         redox conditions
Distance to nearest POTW and          Loading of Hg and MeHg, as well as nutrients, fine
    nearest storm drain discharge        particulates, influencing methylation potential
Number of storm drains feeding        As above.
   into inlet (for urban stormwater
   outfall sites)
Distance to creeks and tributaries    As above. Also, movement of fish upstream to
                                          conditions favoring methylation.
Latitude                              Longer residence time in South Bay favoring reduced
                                         conditions and consequent methylation.
Average depth near site               High biotic activity and repeated wetting and drying at
                                         shallow sites favoring bacterial methylation activity.
Abundance of intertidal mudflat       As above.
   near site
Nearby Land Cover/Land Uses           Multiple potential mechanisms
       Sediment parameters

• Sediment parameters: redox, TON,
  grain size, total and methyl Hg
• Duplicate sediment samples at subset
  of 20 stations
 Questions for the Workgroup
• Is the general approach appropriate?
  – Indicators selected
  – Allocation of effort to spatial vs. interannual vs.
    monthly vs. tool comparison
• Spatial survey design
  – Hypothesis testing approach
  – Sampling sites (wetlands, POTWs)
• Trend sampling
  – Annual sampling sites
  – Monthly sampling sites
• Additional parameters
  – Sediment parameters
              Annual monitoring of trend
                      stations
          Site Name               Region        Site        Impact Type             Sampled
                                                Type
   Long-term monitoring                                                        2005 2006 2007
           stations
China Camp Wetland*            San Pablo Bay   Control   None                   X     X       X
Mouth of Newark Slough         South Bay       Control   None                   X     X       X
Hoffman Marsh at Pt. Isabel*   Central Bay     Control   None                         X       X
Benicia State Park             Carquinez       Control   None                   X     X       X
                               Strait
Candlestick Point              San Pablo Bay   Impact    Wetland creation             X       X
                                                         nearby
Eden Landing at Old            South Bay       Impact    Saltpond breaching     X     X       X
Alameda Creek
Mouth of Alviso Slough         South Bay       Impact    Saltpond breaching     X     X       X
(Pond A8)*
Oakland Middle Harbor          Central Bay     Impact    Habitat creation       X     X
Bair Island at Steinberger     South Bay       Impact    Saltpond breaching     X     X       X
Slough
Hamilton Army Airfield*        San Pablo Bay Impact      Wetland restoration                  X
       0.08
       0.07
       0.06                                    Alviso
                                                 Tiburon
                                            New ark
       0.05                                                 Pt Isabel
FISH



       0.04                 Oakland Harb
                 Treasure Isl


       0.03


              China Camp
              SQ
       0.02

                                      0.5       1.0     1.5 2.0 2.53.0 .5
                                                                      3
                                   SEDIMENT
                     Least Squares Means          Station effect
          0.0


          -0.2
LOGHGDW




          -0.4


          -0.6


          -0.8


          -1.0
                     S   L       P   K       NA        N   L         SL
                 ALV          EN         CHI        DE          EW
                             B                    E            N
                                         STATION

								
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