Report from the September 25-28, 2000
EEGLE All-hands Meeting


[Agenda] [Summary] [Recommendations]
[Sediment Workgroup Report] [Physical-Ecological Interactions Workgroup Report] [Data Assimilation Workgroup Report]

The EEGLE Program held an all-hands meting at the Homestead Conference Center in Glen Arbor, MI. Approximately 40 participants spent three plus days (Sep 25-28) discussing results, issues and potential collaborations. A 130 page workbook was generated prior to the meeting and is available on the EEGLE website, in four parts, at:

  1. Intro.pdf
  2. Hypo1.pdf
  3. Hypo2.pdf
  4. Hypo3.pdf

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Meeting Agenda

Monday, September 25

2:00 - Plenary

2:30 - Brief overviews of all 20 PI Reports (Schwab, Eadie and Fahnenstiel)
4:30 - General discussion
5:00 - Unstructured time

Tuesday, September 26

Plenary - presentations of preliminary modeling results to focus interdisciplinary discussions.

8:30 - Data synthesis (optimal integrated use of data sets and models), McCormick and Murthy
9:00 - Physical - ecological modeling, Chen et al.
9:45 - Sediment transport modeling, Schwab et al., Bedford et al.
10:00 - Charge to Workgroups

Wednesday, September 27

8:00 - Reconvene Plenary to discuss progress
9:00 - Reconvene Workgroups
1:45 - Bus trip to Sleeping Bear Dunes National Park
5:00 - Workgroups or unstructured time

Thursday, September 28


8:00 - Reconvene Plenary - Workgroup reports (~20 minutes)
9:30 - General discussion — consensus on dedicated issue (venue [JGR, Continental Shelf Research, other], participants, and timing)
11:00 - Adjourn

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After several thought-provoking presentations, the participants broke up into three workgroups: Data Assimilation, Sediments Transport, and Physical-Ecological Interactions. Separate brief reports from each workgroup follow at the end of this report, after a brief summary of meeting accomplishments.

Summary of Meeting Accomplishments

First, our program timing has been fortunate; 1998 and 2000 were years that had large sediment resuspension events while 1999 had only small events (figure 1). This provides excellent data for a comparison of transport and impacts. Second, our data and sample collection success rate was quite high, as illustrated in figure 2 and table 1.


1998, 1999, 2000 Plume Images
Figure 1. NOAA AVHRR (Channel 1 - Channel 2) reflectance for sediment resuspension events for the three EEGLE field years (1998-2000). Subjectively, these were the maximum events for the three years that were observed by satellite.
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Timeline of EEGLE activities
Figure 2. Selected EEGLE field activities. The figure provides information on temporal coverage for several types of program activities.
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Table 1. EEGLE Cruise, Web, & Data Statistics as of August, 2000
 

1997 - 2000

Cruises

109

Total Days

396

   

Water Samples

675

Plankton Survey Tows

115

   

Trap samples

816

Current meters

66

Drifter days

690

   

Papers

13

Presentations - Public

46

Presentations - Professional

58

   

Data Objects Submitted

871 (540 MB)

Visits to EEGLE web site

58,325


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Recommendations

At the meeting wrapup, we agreed that:

Special Sessions at:

EEGLE All-hands meetings (3 day workshops)

  • Some PIs thought that a specific writing workshop would be useful, this will be explored and potential participants/schedules organized by the management team. This could range from days to weeks and perhaps be associated with the delivery of products for the Special Issue

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    Workgroup Reports

    Sediment Workgroup Report

  • Status

    Success in collection of a good suite of data - both spatially and temporally

    Caveat: "even with great ingredients you can make a lousy cake", K. Orlandini

    Availability of a number of types of data to constrain models, e.g. in the case of particle fields:
    --direct TSM measurements
    --tripod measurements and moored transmissometers
    --CTD/Transmissometer casts
    --ADCP
    --satellite data

    ** challenge is to integrate/concatenate - importance of cross-linking our data sets and interacting with one another

  • Issues being worked on:

    Transport models - 2 general types
    --Simpler 2D - pc based - long term (years - decades) simulations to test ideas
    --Coupled 3D - supercomputer based for event simulations

    Initial conditions & boundary conditions for modeling efforts
    --materials available for resuspension
    --source - time series of inputs of erosional material
    --particle size distribution effects
    --better "mapping" of bottom type/character

    Improving estimates of mass fluxes in resuspension events ~ 106 MT
    -- alternatives/cross checks on sat data

    Particle residence times, settling rates and horizontal transport rates - promising radionuclide tracer data + integrating into models
    -- Linking time scales & transport to transformation of biogeochemically important materials
    -- tracking particles
    -- offshore transport; again initial conditions important

  • Agreement for the need to meet on periodic basis - next for sediment bunch is the day before EEGLE-KITES @ Argonne - November 29 (our 4th group meeting).

  • Suggest making explicit links and collaborations among all PIs

  • Some Issues under discussion:
    Linking time scales and transport to transformation of BIMs
    Tracking sources of material
    Better "mapping" of bottom type and physical composition
    How tie biogeochemical data to hydrodynamics
    Questions for other groups -- coming

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    Physical-Ecological Interactions Workgroup Report

    Phytoplankton Optics

  • What we know:
    --The recurrent coastal plume (RCP) does not significantly stimulate phytoplankton growth and productivity.
    --Initially, the RCP does not significantly change phytoplankton nutrient status. However, over time, phytoplankton do seem to be more P-deficient post-RCP than pre-RCP

  • Emerging Issues
    --Major issues to be resolved are:
    1. the importance of P utilization by bacteria and
    2. the role of P scavenging by particles

    Phytoplankton populations

  • What we know:
    --Phytoplankton diversity is higher during the RCP Because growth is not stimulated in the plume, this suggests this is a "source" issue Direct resuspension of meroplankton strongly influences (controls?) phytoplankton community structure in the RCP.

  • Emerging Issues
    --Resolve ecological significance of central-lake "donut hole" phenomenon (charge to HAV, WCK, GAF - with WCK having the lead to initiate something)
    --Qualify dynamics of phytoplankton community during resuspension event using:
    representative species as tracers
    material from water column and sediment traps

    --Heterotrophic vs. autotrophic activity
    --N uptake and regeneration vs. light and P regime show that heterotrophic activity dominated during winter-spring except in region influenced by St. Joseph River
    --Phosphorus was not limiting to rates of heterotrophic activity outside of regions of riverine influence
    --In areas of riverine influence, autotrophic activity dominated and responded positively to phosphorus additions

  • Emerging Issues and Questions
    --How close will nutrient cycling rates and patterns relate to microbial food web composition at the riverine vs.. non-riverine sites?

    The Microbial Food Web (MFW)

  • What we know:
    --Biomass and growth rates of heterotrophic components increase with respect to RCP
    --Abundance and biomass of protozoans seems to be correlated with spatial distribution of sediment associated with the RCP
    --Protozoan grazing rates are tightly coupled to bacterial and algal biomass and production

  • Emerging Issues and Questions
    --If the protozoa are consuming so much production, where does it originate?
    --Over time, does bacterial biomass accumulate in the plume?
    --Is there a significant contribution of resuspended meroplanktonic bacteria????
    --Are there differences in grazing rates on particle-associated vs. free bacteria?
    --Is there evidence that the organisms (including resting stages) associated with the nearshore plume are transported offshore?
    --Initial measurements show a substantial amount of production occurs on particles (ca. 60%), but only a few of the proposed measurements have been made thus far.

    The BIG question...
    To what degree does the RCP shift the nearshore environment from autotrophy toward heterotrophy by:

    1. "turning off the lights"
    2. modifying the nutrient regime
    3. shifting community structure as a result of resuspension?

    Mesozooplankton (copepods, cladocera) provide a link to higher trophic levels

    Evidence:
    Late winter/early spring is time of high mesozooplankton reproduction Calanoid copepods are long-lived (generation times of months), therefore, success of juveniles in late winter/early spring is key to success of population in spring In the spring, copepods are the major prey of larval and juvenile fish

    Mesozooplankton

  • What we know:
    --The RCP occurs at a critical time during zooplankton reproduction and recruitment.
    --Copepod clearance (e.g. feeding rates) of MFW organisms are higher than clearance rates of phytoplankton.
    --Egg production and survival rates of offspring of dominant calanoids can be enhanced if females and juveniles are feeding on microzoplankton.
    --There is a significant resuspension of zooplankton resting stages in the RCP.
    --PSS data reveal that there can be shifts in species dominance from year to year

  • Emerging Issues and Questions
    --Does enhanced microbial food web production enhance new mesozooplankton production in the RCP? (Consider time and spatial scales)
    --How does the RCP impact zooplankton recruitment through resuspension of resting stages if the epiphia don't hatch at cold temperatures? Does it "set the table" for later hatching?

    BIG questions and issues:
    --Need to resolve Chen's food web model with ground-truth data and satellite data. How much error is there in the satellite data and model data?
    --During a single event, are there multiple resuspension events that move and resuspend resting stages?
    --If recruitment (i.e., fecundity and survival of offspring, and injection of resting stages) is stimulated, what is its relevance to the entire lake food web? To higher trophic levels later in year?

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    Data Assimilation Workgroup Report

    Progress

  • HF Radar
    1999 data reduction complete
    2000 data reduction underway

  • Physical Oceanography
    Statistical/dynamical analysis of 1999 data completed
    1997-1999 GLERL data on web - 2000 GLERL data in production
    1997-2000 CCIW data on web

  • Hydrodynamic Modeling
    Mar/Apr 1998 and 1999 modeling completed - provided to Chen

  • OSU Sediment transport modeling
    Coding completed for coupled model, parallel version implemented
    Bottom sediment mapping and particle tagging completed
    First week of March 1998 completed

  • Meteorological Modeling

    Critical Questions

  • Can we qualitatively/quantitatively characterize:
  • The conditions necessary to initiate a major event ?
  • The physical conditions within the lake during a major event ?
  • How well do the numerical model hindcasts compare to in-situ and remotely sensed data ?

    Six Months Plans

  • Surrogate climatology of Lake Michigan events (Schwab et al.)
  • 1998-99 major event analysis (Saylor et al) based on observations and models in support of offshore sediment transport
  • Statistical/dynamical analysis of 1998-99 EEGLE data (Murthy et al)
  • March 1998 Sediment model completed (Bedford et al)
  • Meteorological model case studies (Roebber et al)

    One year Plans

  • Statistical analysis of drifter data (McCormick et al)
  • Statistical data comparison (HF, ADCP, Drifter (Vesecky et al)
  • 2000 major event analysis (Saylor et al)
  • Statistical/dynamical analysis of 2000 EEGLE data (Murthy et al)
  • Comparison of HF data with hydrodynamical model (Vesecky et al)
  • Comparison of Sediment model with EEGLE data (Bedford et al)

    Integrated Products

  • Event Climatology - Integrating wave hindcast, wind data/model output, remote imagery, and in-situ measurements
  • Models
    --Numerical
    --Meteorological, hydrodynamic, and sediment dynamic
    --Integration with observations
    --Semi-empirical/conceptual
  • Major event physics integrating physical measurements
  • EOS summary
  • Encourage publications in open literature to assure visibility

    What would we do differently?

  • Abandon point measurements in favor of profiling devices (ADCP)
  • Alter frequency of some data collection devices (example PSS)
  • Increase number of over-water or near-water met stations
  • Include vessel-mounted ADCP transects
  • Obtain micro-structure measurements
  • Improve HF hardware design for freshwater

    New Plans

  • Ecological model (Fahnenstiel and McCormick, others)
  • Dictated by data
  • Null hypothesis: Plume has no biological impacts on Lake Michigan

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