Attachment to email on 6/27/97 MEMO FOR: R. Lawrence Clark, NSF CoOP June 27, 1997 John Wickham, NOAA-COP FROM: Brian J. Eadie, NOAA-GLERL Wayne S. Gardner, U Texas J.Val Klump, U WI-Milwaukee David Schwab, NOAA-GLERL SUBJECT: Response to reviewers comments on the NSF-NOAA Great Lakes COP Project Overall Program: There were a few comments that pertained to the program as a whole: 1. Weakness in overall program integration 2. The role of ice in the plume formation 3. Use of other existing data (tributary inputs, biological data, etc.) 4. Extension of the proposed work to whole lake assessments and other systems Integration: The program has gone through several iterations with integration improving with each step and the clearly defined central theme of the proposal will serve to focus the work. The level of program integration will grow as details of the proposed efforts are discussed among the PIs and efforts are fine- tuned. We plan at least one annual all-hands PI meeting where we will discuss status and progress; our first is scheduled for early August, 1997. The management team take the responsibility of fostering collaboration very seriously, along with their other responsibilities of program administration, representation, and communication. Ice: We are further exploring the importance of ice in plume development. Peter Barnes (Barnes et al., 1993), who recently participated in and published a Lake Michigan ice-erosion study, has provided some further information. His results showed significant sand transport by anchored ice but the total amount of fine-grained material present in the near-shore ice complex is apparently several orders of magnitude less than the amount contained in th eplume. An analysis of satellite ice maps for 1995, a very mild winter, show no apparent correlation of ice cover and the early February trap data associated with the plume. Also, we now have trap data for the 1996 plume period (trap data in the proposal were from 1995 - there apparently was some confusion) and it is clear that the traps begin collection of large amounts of mass coincident with the initiation of the plume - clearly after the last ice was gone from the lake. This tends to support our hypothesis and seems to reduce the importance of direct transport by ice. We are sensitized to the ice issue and will attempt to further assess its importance - but a rigorous test of an alternative hypothesis would require a very large effort that is not included in our program. Because of the ephemeral nature of ice in the southern end of Lake Michigan, no distinct algal community develops in the ice; algal concentrations in the ice are similar to those in the water column when it formed. Moreover, the concentrations of the important spring diatom, Aulocosira islandica and A. italica, are very low in ice, whereas much higher concentrations are found in the sediments. Thus, it is highly unlikely that the melting and movement of ice plays a major role in the initiation and development of the spring diatom bloom. Other data: The reviewerÕs were incorrect in their statement about limited discussion of past studies on lake productivity and what was learned. The introduction and background in the Fahnenstiel et al. proposal synthesizes previous data from Lake Michigan. Other components of the program have also drawn from over 20 years of extensive data and several of the PIs are currently active PIs in a Lake Michigan Mass Balance (PCBs, Hg, etc.) Program about the same size as the proposed COP project. This program is in its last year and much of the information will be relevant (e.g. Tributary monitoring, whole lake surveys, etc.). Finally, the spring bloom is confined to the southern basin of Lake Michigan, and GLERL has an ongoing year round monitoring program, the limited spatial and temporal sampling in this project will not detract from putting the results of this study into a whole-lake annual assessment. Uniqueness of the plume: We now have clear satellite evidence of a similar event occurring coincidently in Lakes Erie and southern Huron. We have not done an extensive search for other examples since the occurance of large, episodic sediment resuspension events are common in most coastal environments. They may not result in a distinct plume, but the biogeochemical consequences will be similar. Because this episodic event is well pronounced and lasts for a least one month, we will be able to determine the impact of this event on annual productivity and ecosystem functioning. This generic information on the role of an episodic event will have application to lakes and aquatic science in general. Individual Proposals: Attached table shows proposed and funded amounts for each proposal and year. 1. Summary Proposal: B. Eadie (GLERL), W. Gardner (U TX), V. Klump (U WI), and D. Schwab (GLERL). Concern about the level of time devoted to program management - the management team has allocated 2.5 months for the first year to launch the program, then approximately half as much per year for the remainder. Since this will be a major NOAA-GLERL activity, more time will be made available for Eadie and Schwab if needed. Time is charged in year 1 and the remaining 4 years are institutional match; approximately twice the cost to the program. There was an annual increase in the travel budget to accommodate management team members travel to NSF CoOP meetings, to brief NOAA COP and other program matters. 2. Retrospective Analysis: Measuring the Historical Magnitude of Turbidity Plumes Using Archived Remote Sensing Imagery: C. Kerfoot (MTU), J. Budd, and R. Stumpf Based on comments, a total of approximately $54,000 was removed from this program, with the majority in the last 2 years. As the reviewers suggested, the majority of the retrospective work will be completed early in the program. The algorithm development and some of the ground truthing activities will be funded directly by MTU as part of the development of a remote sensing center of excellence. 3. Effects of the Lake Michigan Spring Plume on Annual Lake Wide Primary Production: Analysis of Phytoplankton and Dissolved Carbon Concentrations Derived from Satellite Observations of Lake Color: G. Leshkevich (GLERL), B. Lesht, and C. Merry Based on reviewers comments, this entire effort has been eliminated. Lesht and Merry are considering NASA funding. Leshkevich has some funding for algorithm development from NOAA CoastWatch and will collaborate at a reduced level. 4. Physical Oceanography Observations: J. Saylor (GLERL), G. Miller, and M. McCormick Concern was expressed over the resolution of the bottom and surface boundary layers. There will be 12 VACM moorings with 2 VACMs on each mooring. The surface boundary layer cannot be resolved with the VACMs because the meters can be no closer than 10m below the surface in order to comply with USCG regulations for subsurface moorings and vessel clearance. Surface floats cannot be used in the winter because of ice concerns. The bottom meter will be placed within 1m of the bottom and should provide useful information for colleagues focusing on bottom resuspension. The ADCPs will be able to provide information on the flow field closer to the surface than we are able to obtain with the VACMs. Under the barotropic conditions of this study we believe that the planned vertical resolution is adequate. More importantly, it is achieving adequate resolution of the major horizontal scales of the hypothesized flow field that was our top concern and priority in planning our observation strategy and mooring configuration. ARGOS resolution and drogue configuration. We do not use ARGOS positioning but rather use ARGOS as a data platform for relaying GPS positions. The GLERL drifters have all been designed for internal data storage and retrieval. The CODE type drifters will be GPS based as well. The drogue configuration for the GLERL drifter is a holey sock type approximately 3m long by 1.5m in diameter. The buoy and drogue are designed to minimize wind and wave induced slippage and have both a shallow center of effort (approximately 3m) and an aspect ratio greater than 50:1 (underwater cross-sectional area/ buoy freeboard cross-sectional area). The CODE type drifters have also been designed to be surface tracking with minimal slippage and a high aspect ratio. The near surface center of effort of these drifters negates any concern that current shear may have on excess buoy/drogue slippage. 5. Episodic Events and Cross-Margin Transport in the Great Lakes: HF Radar Observations of Currents, Winds, and Waves: J. Vesecky (UMI) Vesecky: Two issues were raised by a reviewer concerning the proposed HF radar observations to obtain spatial maps of surface currents, surface current shear, wind direction and wave conditions. The two issues were maximum range over the fresh water in Lake Michigan and adequate resolution to achieve overall experiment goals. It is well known that the maximum range of HF radar observations will be reduced in Lake Michigan because of propagation losses over fresh water. We propose the following actions to improve signal to noise performance over fresh water. The actions are listed in order of difficulty. 1. Increase the radar integration time from 15 minutes to 1 hour or more 2. Use lower or higher operating frequencies to find the best combination of propagation and waveheight of the resonant surface wavelength 3. Increase the energy in a radar pulse by increasing the length of the radar's coded pulse sequence 4. Increase transmit power by a factor of ten to twenty using 1 kW linear power amplifiers 5. Increase antenna gain by the use of two or three element arrays on transmit and possibly the use of twin loop receive antennas. From studies of propagation over fresh water relative to salt water we anticipate that a combination of the actions above will provide useful HF radar observations out to a maximum range of 20 to 40 km which is adequate to observe the near-shore waters of Lake Michigan that are of interest in the proposed investigation. Regarding resolution we proposed to use a polar grid spacing of the current, wind direction and wave data fields of about 750 m in range from the radar site and from 7° to 30° in azimuth, over the four radar frequencies. To achieve this goal and further improve the resolution we propose to take the following action to decrease the resolution cell size: 1. Use direction finding techniques, such as the music algorithm, to decrease the azimuth grid spacing, especially at the lower frequencies. 2. Increase the number of antennas in the receive antenna array (the antenna multiplexer is adequate for twice as many antennas as we currently use) 3. Decrease the chip length in the coded pulse sequence. We anticipate that a combination of the actions proposed above will provide both adequate range and resolution for the HF radar to fulfill its expected role in the proposed study of the impact of episodic events on nearshore-offshore transport in the Great Lakes. For both increased range and better resolution the proposed actions are needed for all the applications of the radar and so will be supported by funding from other sources as well as NSF-NOAA COP funds requested here. 6. Hydrodynamic Modeling Program: D. Schwab (GLERL) and D. Beletsky We are planning to use a 2km grid in the beginning of the project, in situations when the lake is essentially homogeneous. With the computer enhancements scheduled for the beginning of the third program year, we will be able to use 1km grid in situations where baroclinic components, like near-bottom symmetric instabilities (Allen et al. 1995, 1996), become more important. We will also consider using grid nesting to employ even finer horizontal resolution. We will experiment with idealized forcing cases before scenario testing cases as suggested by the reviewer. We will consider using data assimilation techniques, possibly in collaboration with the graduate student at OSU who we added to the Bedford proposal. An extensive program for model skill assessment including standard statistical techniques as well as cross-spectral analysis will be undertaken. Chen will be using the same version of POM in the lower food web modeling component of the program. In general, we do not consider the sediment-laden ice rafting to be an important mechanism for fine- grained sediment transport in the Great Lakes. Previously reported data suggested that this mechanism is mostly important for coarse sediments, getting entrained in the ice in the very narrow nearshore area (Barnes et al. 1993, 1994). However, the development of a dynamic ice model as proposed in the program will provide us with an opportunity to assess the potential contribution of sediment-laden ice to fine-grained sediment transport. Ice model results will be verified by comparing simulated ice extent and concentrations to that of the NIC ice charts, and also SAR imagery available from the NOAA CoastWatch. Indirectly, ice thickness will be verified by the ability of the model to simulate ice disappearance. In conclusion, we want to mention that POM is an established tool for nearshore simulations. It has been tested extensively in many coastal and estuarine environments. 7. Meteorological Modeling Program: P. Roebber (UWM) There were no critical comments about this proposal, only that this component was necessary for the overall modeling program. No change in budget. 8. Sediment Resuspension and Transport Modeling Program: K. Bedford (OSU) Ellen McDonald will be unable to participate and her proposed efforts will be executed by the addition of two post-doctoral assisstants at OSU, Philip Chu and David Podber, who have considerable experience in numerical modeling. There was a suggestion by NSF to add a student to the modeling program and that has been included in this proposal; the additional graduate student on the project will be co-advised by Dr. Schwab in his capacity as adjunct faculty in the meteorology program here at OSU. After adding resources to cover the extra student, the overall budget was then reduced by approximately 10% per year. We chose to eliminate dollars evenly over the five year life of the project in anticipation of the modeling continuing evenly over the life of the project. This is in contrast to the field personnel who must front load during the first three years followed by a large drop off in the latter two years with field work being completed. The maximum grid size contemplated for the high resolution sediment modeling will be 0.5km. We anticipate trying 0.25km but this test will be more in the nature of a sensitivity study. A comment was made concerning Dr. Bedford's lack of experience in sediment transport. Dr. Bedford has 18 years of productive research in the sediment transport field. With J. Lynch at WHOI, his group was the first to vigorously calibrate ultrasonic sediment concentration profiling devices. His group was the first to directly field measure entrainment and erosion at the sediment water interface for which they received the Huber and Hilgard Prizes from the American Society of Civil Engineers. His group was the first to field validate the Glenn and Grant wave-current sediment boundary layer model by high resolution sediment profile data. The near bottom wave current layer prediction and model formulation were confirmed. Dr. Bedford's group has just completed a wavelet analysis approach to separating swell, wind wave, current and turbulence data in near surface sediment transport data. His group was the fourth group in the US to publish a fully robust time varying sediment resuspension model after Mehta, Krone, and Lick and Sheng that incorporated a "bottom model". This model was then followed by a full consolidation representation for the bottom. Arrangements are being made to have Dr. Lick serve as a consultant on the coagulations, flocculation and disaggregation aspects of the model. 9. Sediment Resuspension and Transport: B. Eadie (GLERL), D. Edgington, B. Lesht, V. Klump, K. Nealson, J. Robbins, and B. Tonner There were no specific critical comments on the GLERL component of this effort - however we were able to reduce our cost by approximately 15% over the 5 year program. Most of this reduction was in increasing the GLERL match, which is now several times that from the NOAA-COP and will not result in any loss of effort. Some reductions were also made in year 4 and 5 travel and supply budgets reflecting the lack of any field work in those years. Similarly there were no critical comments regarding the proposed benthic work by Lesht. His program was reduced by approximately 7% to help meet the budget targets. Based upon the panel's comments the University of Wisconsin has made the following revisions to their proposed budget and work. Our overall budget is reduced by $411,724 or 18.7%. They have eliminated nearly all of the particle characterization work by Nealson, including funds for ESEM/EDS and TOFMS analytical work. We have retained the postdoctoral support for Tonner's work. This represents the only particle tracer work, other than the radionuclide studies, that will be carried out in this project. This work has great promise, a strong fit to the particle aging studies, and is very low cost (2 mo. of postdoctoral support). The microscopic work proposed by Tonner and Nealson using the advanced light source at the DOE lab at Berkeley provides a very exciting capability of examining the structure of particle surfaces in terms of elemental distribution (including bacteria) and the chemical environment surrounding individual atomic sites. This will be very important in meeting our goal of understanding particle transformation. It is generally recognized that adsorptrion at particle surfaces is a dominant process and a great deal is already known. We are reducing Nealson's supported effort, however, to 0.5 month. This will keep him in the mix and allow him to co-supervise one of the graduate students supported on the grant. These Research Assistantships are 50% match funded by our Graduate School and represent a significant leveraging of support which we do not want to lose. They have reduced the subcontract to Orlandini by ~10% in years. 1-3 and eliminated it altogether in years 4 & 5; his CV, missing from the submitted proposal, is attached. With respect to the ROV studies, several of the reviewers noted the importance of this sampling platform to the particle transport and transformation studies. It will provide valuable observational data and sediment floc samples that can be obtained in no other way. The system we will be using is not a simple ROV, but a complex sampling system that has been developed in cooperation with Dave Lovalvo, of Eastern Oceanics Inc., a small one man operation. We have worked with Lovalvo for 10 years, with significant support from the NOAA National Undersea Research Program (NURP). Based upon this experience and the complexity of the system, we are certain that the costs associated with this subcontract are very reasonable, and are equivalent or slightly less than NOAA contracts with Eastern Oceanics over the last few years. The U WI has increased the budget request for purchase of the ultra-low level beta counter slightly ($7500). This was necessitated by an increase in the estimated cost of the instrument, a decrease in the overall budget and the concomitant lessening of the matching funds available to the Center for Great Lakes Studies (CGLS). CGLS will still provide up to $5,000 in matching support, in addition to $27,500 in a dollar for dollar match for this item provided by our Graduate School, for a total match of $32,500. 10. Phosphorus Dynamics and Production in Lake: J. Cotner (TAMU), T. Johengen Based on comments, the geochemical kinetics work of Noel Urban was eliminated completely and the phosphorus measurement work of Johengen was reduced by approximately 50%. His remaining effort will be on measuring ambient fields of P concentration in the plume and measurements of P on particles collected in the sediment resuspension proposal (traps and sediment floc; Eadie et al.). These cuts resulted in approximately 40% reduction per year. Noel Urban is seeking other funding to re-enter the program. Cotners P uptake and storage work was relatively undisturbed. 11. Impact of Episodic Transport and Resuspension on Coastal Phytoplankton Processes: A Case Study of the Lake Michigan Recurrent Coastal Plume: G. Fahnenstiel (GLERL), S. Lohrenz, O. Schofield, D.Millie, and L. Goad. The major concern for this project centered on the application of high-tech instruments. We feel that our state-of-the art instrumentation and derived optical measurements are critical to the success of the program. Moreover, we do not feel that they are risky; rather our experience suggests the opposite when these techniques are appropriately used. Our optical measurements will be backed up using traditional instrumentation and techniques (e.g., LICOR instruments). The collection of state-of-the-art bio-optical data will also be of paramount importance for thoroughly characterizing the optical field in this important freshwater environment. 1) Characterization of in situ absorption and scattering properties are critical for the development of a predictive model for the subsurface irradiance field. The ac-9 provides these data. While this instrument has had its share of problems, WetLabs has made improvements in design and provided more detailed guidance to ensure that the instrument provides high quality data. The newer models (which we proposed to purchase) would include the most recent improvements in design. Steve Lohrenz has been working with Naval Research Laboratory investigators in various studies that have evaluated the performance of the ac-9. When proper protocols are followed, the instrument yields consistent and reliable results. We proposed to check the performance of the instrument using an independent method for determining particulate absorption. 2) The Satlantic Spectroradiometer is crucial for providing direct measurements of the subsurface spectral irradiance field. Again, this is essential for developing a model of the light field. This is a vital component of our project, as our objectives include determining the role of the resuspension plume on light and its associated effects on the growth, productivity and photosynthetic characteristics of the phytoplankton population. A 14 channel instrument is required to minimally resolve the spectral properties of the light field. The measurements must be made at the same time as our sampling. Therefore, we cannot rely on other projects to make these measurements for us. The Satlantic is considered the top-of-the-line industry standard for in situ radiometric profiling. Both of these instruments require regular calibration and maintenance. Other instruments owned by Rutgers and USM will not be dedicated to this project and are, therefore, not guaranteed of being available or properly maintained for this project. In view of the importance of this component to our proposal, we feel we must not compromise this aspect of the project. One of the goals of this program was to bring advanced techniques to bear on problems in the Great Lakes. If we sacrifice this instrumentation, we will reduce the quality of the science and the scientific productivity. Regarding the WetLabs fluorescence measurements, this instrument is being provided at no cost to the project. There is little concern about managing the data stream since we have used these instruments in the past, and are very comfortable with the software. The productivity models do not strictly rely on the in situ absorption or fluorescence data. Those data are crucial to modeling the light field, but are not explicitly required for the productivity measurements. Our productivity measurements already have "back-up" built in to them, in that we do not depend on the ac-9 data or fluorescence data for results. Rather, the use of the ac-9 and other in situ optical data should provide for more detailed spatial and temporal resolution of primary production, allowing us to better match our results with the physical and chemical data sets and be compatible with remote sensing data sets (if and when they are available). Finally, a thorough understanding of phytoplankton dynamics is needed for all other biological projects in this program funded, and the most effective way to generate a high resolution picture in both space and time is to use optical approaches. BUDGET CONSIDERATIONS: Our project budget was reduced by approximately 6% during the 5 year program. In order to achieve these cuts and still maintain the high quality of science, GLERL/NOAA increased its budget in year 1 (carryover) and absorbed most of the reductions during years 2 and 3. This loss will be compensated by an increased commitment of GLERL match resulting in minimal reduction of effort. We believe the understanding of the Great Lakes ecosystem will be advanced significantly with the application of current oceanographic techniques. During the synthesis phase of this program (years 4 and 5), uniform budget cuts (12 and 9%) were taken by all investigators. In some cases these cuts were minimized by increases in base support from home institutions. Overall, we believe our proposed cuts will have a small impact on the science. 12. The Recurrent Coastal Plume in Lake Michigan: A Critical Event for Copepod Reproduction and Recruitment: H. Vanderploeg (GLERL) and M. Bundy In response to reviewers' comments, the proposed laboratory feeding work and direct observations of zooplankton feeding and swimming, have been eliminated. Instead the focus will be on the fieldwork component that was favorably reviewed. This component will emphasize: (1) distribution of the zooplankton as related to the plume and physics; (2) production measurements in the field, necessary for Chen's model and the resting egg story; and (3) collaboration with Gardner and Lavrentyev to connect trophic interactions of the mesozooplankton to those of the microzooplankton. The new streamlined study requires Bundy's effort at half time for years 2 and 3 and a reduced effort in years 4 and 5 (approximately 50% reduction). Additional savings have also been made by increasing the GLERL match to more than 2:1. 13. The Effects of a Recurrent Spring Plume on the Dynamics and Structure of the Lower Food Web in Southern Lake Michigan: W. Gardner (U TX) and P. Lavrentyev This proposal had no critical comments; the significant budget reductions (ca. 12%) were transferred to GLERL through Eadie's budget in the resuspension project. This was to partially cover the inclusion of Joann Cavaletto, Gardner's former support-scientist at GLERL, who will support his proposed work. The request for Cavaletto's salary had been in the original proposal, as a separate component, but, by mistake, this component was not included with the proposal to the Co-op program in the submission process by The University of Texas. GLERL will match the transferred funds approximately 2:1. Overall, this modification results in an increased effort in this project over what was requested but is appropriate for the proposed work. 14. Nutrient and Lower Food Web Dynamics: A Coupled Biological and Physical Modeling Study: C. Chen (UGA) There were no critical comments on this proposal. Chen will use the same version of the Princeton Ocean Model as will be used by Schwab. References Allen, J.S., P.A. Newberger, and J. Frederick. 1995: Upwelling circulation on the Oregon continental shelf: Part 1: response to idealized forcing. J. Phys. Oceanogr. 25:1843-1866. Allen, J.S., P.A. Newberger, and R.A. Holman. 1996 Nonlinear shear instabilities of alongshore currents of plane beaches. J. Fluid Mech. 310:181-213. Barnes, P.W., E.W. Kempera, E. Reimnitz, M. McCormick, W.S. Weber, and E.C. Hayden. 1993. Beach profile modification and sediment transport by ice: an overlooked process on Lake Michigan. J. Coastal Res. 9:65-86. Barnes, P.W., E.W. Kempera, E. Reimnitz, M. McCormick. 1994. The influence of ice on Lake Michigan coastal erosion. J. Great Lakes Res. 20:179-195. KENT A. ORLANDINI Scientific Associate, Environmental Research Division Argonne National Laboratory Argonne National Laboratory, Environ. Research Div., Argonne, IL Phone: 708-252-4236 S.S. No: 336-28-3478 EDUCATION: B.S., University of Illinois, Urbana, IL, 1957 (Chemistry) POSITIONS HELD: Research Technician, Chemistry Division, Argonne National Laboratory (ANL), 1957-58 Research Technician/Scientific Assistant, Chemistry Div., ANL, 1961-71 Research Director, GBS Laboratories, Inc., Sycamore, IL, 1971-73 Scientific Associate, Environmental Research Division, ANL, 1974-present RESEARCH INTERESTS: Radiochemistry and nuclear counting techniques, actinide measurements, isolation of colloidal materials using hollow-fiber ultrafiltration, field studies of subsurface transport of radionuclides, measurement of atmospheric radioactivity rain, development of improved electrodeposition methods for radiochemical counting. SELECTED PUBLICATIONS RELATED TO PROPOSED PROJECT: Gaffney, J.S., N.A. Marley and K.A. Orlandini. 1992. Evidence for thorium isotopic disequilibria due to organic complexation in natural waters. Environ. Sci. Tech. 26:1248-1250. Orlandini, K.A., W.R. Penrose, B.R. Harvey, M.B. Lovett and M.W. Findlay. 1990. Colloidal behavior of actinides in an oligotrophic lake. Environ. Sci. Technol. 24:706-712. Gaffney, J.S., K.A. Orlandini, N.A. Marley and C.J. Popp. 1994. Measurements of Be-7 and Pb-210 in rain, snow and hail. Journal Applied Meteorology, V. 33, No. 7. July 1994. Alberts, J.J., M.A. Wahlgren, K.A. Orlandini and C.A. Durbahn. 1989. The distributions of 239, 240Pu, 238Pu, 241Am anad 137Cs among chemically-defined components of sediments, settling particulates, and net plankton of Lake Michigan. J. Environ. Radioactivity 9:89-103. Nelson, D.M. and K.A. Orlandini. 1986. The role of natural dissolved organic compounds in determining the concentrations of americium in natural waters. In: Speciation of Fission and Activation Products in the Environment, R.A. Bulman and J.R. Cooper, eds., Elsevier Applied Science, London. ADDITIONAL SELECTED PUBLICATIONS: Nelson, D.M., K.A. Orlandini and W.R. Penrose. 1989. Oxidation states of plutonium in carbonate-rich natural waters. J. Environ. Radioactivity 9:189-198. Orlandini, K.A., J.S. Gaffney and N.A. Marley. 1991. Improved method for analysis of radium in natural waters. Radiochimica Acta 55:205-207. Marley, N.A., J.S. Gaffney, K.A. Orlandini, K.C. Picel and G.R. Choppin. 1992. Chemical characterization of size-fractionated humic and fulvic materials in aqueous samples. The Science of the Total Environment 113:159-177. Orlandini, K.A., W.R. Penrose and D.M. Nelson. 1986. Pu(V) as the stable form of oxidized plutonium in natural waters. Marine Chemistry 18:49-57. Edgington, D.N., J.A. Robbins, M.P. Gustin, K.A. Orlandini, S.C. Colman, M.A. Grachev and Ye Likhoshway. 1996. Uranium-series disequilibrium, sedimentation, diatom frustules, and paleoclimate change in Lake Baikal. Earth and Planetary Science Letters. In press.