1982-2002; ill.; Includes bibliographic references; Issues lack volume numbering
Form 10*226 (April 1966) UNITED STATES DEPARTMENT OF THE INTERIOR NATIONAL PARK SERVICE INVESTIGATOR'S ANNUAL REPORT (Natural Sciences Research) This form is to be completed by the researcher and returned to the Superintendent of the Park by JANUARY 1. See reverse for additional instructions. TO SUPERINTENDENT Crater Lake REGION 1. Project Title Particle fluxes in Crater Lake and their relationship to water clarity 2. Name(s) of Researcher(s) and Inatitution(s) Jack Dymond College of Oceanography, Oregon State University 3. Source(s) and Amount(a) of Funds Other Than NPS, if Any College of Oceanography, Oregon State University 4* Starting Date of Project June 1983 5. Percent Completion of Project to Date: io% 2-3 Est. Additional Time Required for Completion Beyond January 1st; Years Months 7. Summary: (a) of progress; (b) of significant findings, if any, to date; (e) recommendations regarding future course, i.e., on basis of work so far, should it proceed as planned, be reoriented, expanded, reduced, time schedule and support level adjusted, etc.; The goal of this project is to contribute to the understanding of the declining water clarity at Crater Lake by measuring the flux and composition of particles falling through the water column of the Lake. Water-column particle fluxes reflect outside inputs of nutrients and inorganic particles to the Lake. Thus, the flux of particle-associated nutrient elements measured below the photic zone defines not only the productivity of the photic zone, but also the flux of nutrients to the photic zone. Since Crater Lake is a nutrient-limited lake, any increase in nutrients to the Lake will result in increased flux of biogenic particles through the water column. Particle fluxes at Crater Lake can be measured with devices known as sediment traps, and on July 12, 1983, my research group deployed two sediment traps on a subsurface mooring anchored in approximately 465 m water depth. One trap was located at 200 m depth to collect particles falling from the photic zone, and the second trap was moored 7 m above bottom to measure the flux of particles reaching the Lake floor. This mooring was in place throughout the summer season and was recovered on September 12, 1983. An identical mooring with two traps at the same depths was deployed on September 13, 1983. Through a timer mechanism, this mooring will be released from the bottom on July 10, 1984. Thus, these two moorings will provide data on particle fluxes for an entire year, partitioned into a summer and a winter °Chemical analyses of the particle samples recovered in September are currently in progress. These data will allow us to delineate biogenic and non-biogemc sources of particles. In the deep portions of the Lake, precipitates from Mrothermal springs may contribute to the particle flux and be a cause of deep water turbidity. Other inorganic particle fluxes are the result of erosion of the caldera wall and wind-blown sources. Chemical analyses of the trapped particles coupled with our (Use Additional Sheets it Necessary) V wW » ANUtU J Date 8. Signature of Investigator 9. RSP Number N A6 Project Summary (continued) -2- linear programming-based normative analysis scheme will provide quantitative data on the fluxes of organic and inorganic particles. Our measured bulk fluxes for the summer season are approximately 1 mg/cm2/yr. This rate is yery low compared to flux measurements of other lakes and is comparable to moderate to low productivity areas of the open ocean. During our two 1983 expeditions ot the Lake, we also took water samples for 222Rn, 226Ra, and trace metal analyses. 222Rn and 226Ra are daughter products in the decay of the naturally occurring 238ut and their abundance can indicate the importance of hydrothermal sources. Because we were limited to the upper 300 m of water depth, our 222Rn and 226Ra measurements generally only demonstrated the very low background of these isotopes in the Lake. One sample near the summit of the submerged Merriam Cone, however, had relatively high 222Rn contents indicative of a hydrothermal source. Trace metal analyses were made by Dr. Robert Collier as part of a separate project funded by Oregon State University Research Office. These measurements indicated exceedingly low trace metal contents for the Lake, suggesting the possibility that trace metals, such as Zn and Fe, could be limiting productivity of the Lake. Higher trace metals observed in the surface water suggest these elements are introduced to the lake by eolian or intercaldera seeps. A 7
Form 10*226 (April 1966) UNITED STATES DEPARTMENT OF THE INTERIOR NATIONAL PARK SERVICE INVESTIGATOR'S ANNUAL REPORT (Natural Sciences Research) This form is to be completed by the researcher and returned to the Superintendent of the Park by JANUARY 1. See reverse for additional instructions. TO SUPERINTENDENT Crater Lake REGION 1. Project Title Particle fluxes in Crater Lake and their relationship to water clarity 2. Name(s) of Researcher(s) and Inatitution(s) Jack Dymond College of Oceanography, Oregon State University 3. Source(s) and Amount(a) of Funds Other Than NPS, if Any College of Oceanography, Oregon State University 4* Starting Date of Project June 1983 5. Percent Completion of Project to Date: io% 2-3 Est. Additional Time Required for Completion Beyond January 1st; Years Months 7. Summary: (a) of progress; (b) of significant findings, if any, to date; (e) recommendations regarding future course, i.e., on basis of work so far, should it proceed as planned, be reoriented, expanded, reduced, time schedule and support level adjusted, etc.; The goal of this project is to contribute to the understanding of the declining water clarity at Crater Lake by measuring the flux and composition of particles falling through the water column of the Lake. Water-column particle fluxes reflect outside inputs of nutrients and inorganic particles to the Lake. Thus, the flux of particle-associated nutrient elements measured below the photic zone defines not only the productivity of the photic zone, but also the flux of nutrients to the photic zone. Since Crater Lake is a nutrient-limited lake, any increase in nutrients to the Lake will result in increased flux of biogenic particles through the water column. Particle fluxes at Crater Lake can be measured with devices known as sediment traps, and on July 12, 1983, my research group deployed two sediment traps on a subsurface mooring anchored in approximately 465 m water depth. One trap was located at 200 m depth to collect particles falling from the photic zone, and the second trap was moored 7 m above bottom to measure the flux of particles reaching the Lake floor. This mooring was in place throughout the summer season and was recovered on September 12, 1983. An identical mooring with two traps at the same depths was deployed on September 13, 1983. Through a timer mechanism, this mooring will be released from the bottom on July 10, 1984. Thus, these two moorings will provide data on particle fluxes for an entire year, partitioned into a summer and a winter °Chemical analyses of the particle samples recovered in September are currently in progress. These data will allow us to delineate biogenic and non-biogemc sources of particles. In the deep portions of the Lake, precipitates from Mrothermal springs may contribute to the particle flux and be a cause of deep water turbidity. Other inorganic particle fluxes are the result of erosion of the caldera wall and wind-blown sources. Chemical analyses of the trapped particles coupled with our (Use Additional Sheets it Necessary) V wW » ANUtU J Date 8. Signature of Investigator 9. RSP Number N A6 Project Summary (continued) -2- linear programming-based normative analysis scheme will provide quantitative data on the fluxes of organic and inorganic particles. Our measured bulk fluxes for the summer season are approximately 1 mg/cm2/yr. This rate is yery low compared to flux measurements of other lakes and is comparable to moderate to low productivity areas of the open ocean. During our two 1983 expeditions ot the Lake, we also took water samples for 222Rn, 226Ra, and trace metal analyses. 222Rn and 226Ra are daughter products in the decay of the naturally occurring 238ut and their abundance can indicate the importance of hydrothermal sources. Because we were limited to the upper 300 m of water depth, our 222Rn and 226Ra measurements generally only demonstrated the very low background of these isotopes in the Lake. One sample near the summit of the submerged Merriam Cone, however, had relatively high 222Rn contents indicative of a hydrothermal source. Trace metal analyses were made by Dr. Robert Collier as part of a separate project funded by Oregon State University Research Office. These measurements indicated exceedingly low trace metal contents for the Lake, suggesting the possibility that trace metals, such as Zn and Fe, could be limiting productivity of the Lake. Higher trace metals observed in the surface water suggest these elements are introduced to the lake by eolian or intercaldera seeps. A 7