Grantee Research Project Results
2002 Progress Report: Behaving Drifters as Gymnodinium breve Mimics
EPA Grant Number: R829370Title: Behaving Drifters as Gymnodinium breve Mimics
Investigators: Kamykowski, Daniel , Wolcott, Thomas G. , Janowitz, Gerald S.
Institution: North Carolina State University
EPA Project Officer: Packard, Benjamin H
Project Period: November 19, 2001 through November 18, 2004 (Extended to May 18, 2006)
Project Period Covered by this Report: November 19, 2001 through November 18, 2002
Project Amount: $423,493
RFA: Ecology and Oceanography of Harmful Algal Blooms (2001) RFA Text | Recipients Lists
Research Category: Water Quality , Water , Aquatic Ecosystems
Objective:
Because Gymnodinium breve recently was renamed Karenia brevis, the Gymnodinium breve Population Mimic (GBPM) is now called the Karenia brevis Population Mimic (KBPM). The objective of this research project is to follow the trajectories of free-ranging, buoyancy-adjusting floats programmed to act as KBPM on the west Florida shelf and to incorporate the results into evolving physical-biological models. The following hypotheses will be tested: (1) K. brevis exhibits positive chemotaxis toward inorganic and organic nutrients; (2) K. brevis adjusts its migration in response to the nutrient sources that yield a chemotactic response when they are available in only part of a laboratory water column; (3) KBPMs and CODE drifters placed in proximity to each other follow similar tracks; (4) KBPM that migrate vertically in the same water column as other KBPM distributed and maintained at different water column depths integrate the horizontal flows encountered during the vertical migration and track differently than the KBPM maintained at any given depth; (5) the environmental exposure recorded by the migrating KBPM will support better relative growth than that recorded by the stationary depth KBPM when entered into an existing model of K. brevis' physiological responses; (6) KBPM, programmed to vertically migrate, track in situ K. brevis populations when dropped into natural aggregations of K. brevis; and (7) physical-biological models incorporating information obtained from KBPM better simulate natural events (population growth and physical aggregation) than those that do not.
Progress Summary:
We made progress on all of the proposed hypotheses. Preliminary experiments were performed in support of chemotaxis technique development. The chemotaxis chambers were redesigned to provide control and experimental choices for the same population. The mesocosm incubator room was upgraded to power high wattage bulbs that provide light intensities closer to natural noon levels. The mesocosms were upgraded with improved support structures and with tops for cleaner operation. Preliminary experiments were performed in support of mesocosm technique development. An acoustic Doppler current profiler (ADCP) and a digital global positioning systems (GPS) unit were ordered to measure the horizontal and vertical velocities in the area of the KBPM field experiments. An environmental measuring system was assembled by SubChem Systems Inc., which includes a CTD, a PAR quantum sensor, a SubChemPak nutrient analyzer, and a chlorophyll fluorescence/particle concentration sensor. Laboratory experiments were performed in support of behavioral model improvements for the KBPM. For example, eight different clones of K. brevis divide into two different photoresponse groups, one more light capable than the other. This photoresponse quality will be incorporated into the KBPM productivity response program. Design of the KBPM has proceeded on multiple fronts. The multitude of new components released since the prototype version of the KBPM has presented a rich variety of new options. The approach that has been selected shifts much of the computational load to a much more capable PIC microcontroller (the "spinal gangion"). This device will be able to read all sensors, drive the (modulated) pinger and radio beacon, and control the buoyancy adjustor. The high-speed DS87C530 "brain" microcontroller will be invoked only when complex mathematical operations are required (e.g., exponential calculations for onset/decay of photoinhibition). Other major advancements are 128K of nonvolatile memory for data logging, IRDA-compliant wireless communication with a host computer, and a smaller, simpler PC board. Both of the microcontrollers will be quickly field-reprogrammable without opening the pressure housing. The Liu, et al. (Marine Ecology Progress Series 2001;213:13-37) K. brevis behavioral model was generalized to incorporate a three dimensional, time-dependent velocity field over a variable topography utilizing a stretched coordinate in the vertical (sigma coordinates). The model was tested with a constant eddy viscosity, steady, wind-driven, alongshore-invariant current field although any velocity field, could be incorporated. The velocity field can be utilized to track a programmed KBPM and compare its trajectory relative to that of a K. brevis patch.
Future Activities:
Laboratory experiments will continue to examine biochemical pools and physiological/behavioral rates critical to the parameterization of the K. brevis biological model. Small-scale experiments include chemotaxis trials using different sources, swimming velocity characterization in response to changes in selected environmental factors, and a characterization of swimming path characteristics at different water column locations over the course of a diel vertical migration. Larger scale experiments will use nutrient-stratified mesocosms to investigate nutrient-influenced diel vertical migration in response to selected limiting nutrients such as nitrate and phosphate. The major support equipment has been purchased. We will finalize the KBPM design and begin mass production of KBPM for field deployment. The biological part of the biophysical model will be upgraded with the same parameterization used in the KBPM. Comparison runs will determine how the full range of K. brevis physiological/behavioral capabilities determined in the laboratory influences the ability to predict bloom development based on standard physical forcing.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 39 publications | 11 publications in selected types | All 10 journal articles |
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Type | Citation | ||
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Liu G, Janowitz GS, Kamykowski D. Influence of current shear on Gymnodinium breve (Dinophyceae) population dynamics: a numerical study. Marine Ecology Progress Series 2002;231:47-66. |
R829370 (2002) R829370 (Final) R827085 (2000) R827085 (2001) R827085 (Final) |
Exit Exit |
Supplemental Keywords:
marine, ecology, environmental chemistry, physics, organism, measurement methods, modeling, Southeast, ecosystem protection/environmental exposure and risk, RFA, water, biology, ecological risk assessment, ecology, ecology and ecosystems, oceanography, algal blooms, ECOHAB, harmful algal bloom, HAB, Karenia brevis population mimics, KBPMs, K. brevis behavioral submodel, K. brevis red tides, K. brevis toxins, Gymnodinium breve., RFA, Scientific Discipline, Water, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Oceanography, algal blooms, Ecological Risk Assessment, Ecology and Ecosystems, Biology, brevetoxins, Gymnodinium breve toxins, ECOHAB, G. breve Population Mimics (GBPMs), G. breve red tidesProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.