Grantee Research Project Results
Final 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 Amount: $423,493
RFA: Ecology and Oceanography of Harmful Algal Blooms (2001) RFA Text | Recipients Lists
Research Category: Water Quality , Water , Aquatic Ecosystems
Objective:
The objectives of this research project were to: (1) parameterize a representative physiological/behavioral Karenia brevis model based on laboratory experiments; (2) construct K. brevis Population Mimics (KBPM); (3) follow the trajectories of the free-ranging, buoyancy adjusting floats programmed to act as K. brevis on the west Florida shelf; and (4) incorporate the laboratory and field results into evolving physical-biological numerical models.
Taxonomic Update
Because Gymnodinium breve was renamed Karenia brevis, the Gymnodinium breve Population Mimic (GBPM) is now called the Karenia brevis Population Mimic (KBPM).
Summary/Accomplishments (Outputs/Outcomes):
Physiological/Behavioral Program
Extensive laboratory measurements and field verification provided background information for the controlling physiological/behavioral program. K. brevis swims at about 1 m h-1 over most of its natural temperature range and has a complex response to light intensity related to its photosynthetic activity. Photoinhibition increases as cell density increases. K. brevis exhibits a tendency toward chemotaxis and exhibits enhanced dark nutrient uptake after 12 hours of nutrient deprivation. K. brevis changes its pattern of vertical migration in response to the distribution of light and nutrients in the available water column and the fullness of its internal carbon and nitrogen pools. K. brevis appears well-suited to maintain populations near the sediment-sea interface at low light intensities and to grow at the air-sea interface during bloom conditions. These data supported the construction of a biological model that included both realistic physiological and behavioral responses to external environmental cues and to internal cellular state.
KBPM
The KBPM is now an operational unit. The design is based on a high-end Microchip PIC microcontroller. All of the circuitry (except temperature sensor, IR communications transceiver, GPS, and radio beacon module) fits an 11-cm diameter PC board. It comprises the PIC; 64-256K of nonvolatile data memory; real-time clock; sensors for rotation, pressure, and light; and drivers for the pinger, buoyancy pump, radio and LED beacons, and conductivity cell. Reprogramming now can be conducted via an external IR serial port. The mimic’s user interface includes a menu providing access to a host of operational parameters (sensor calibrations, wake interval, datalogging frequency, variables to log, migration models, GPS fix times, recovery time, upload of logged data, etc.).
The “speed through water” sensor uses a new device, the Austria Microsystems AS5020. The program uses the output to sense angular velocity caused by spin of the “propeller” drag skirt as the device moves up or down through the water. The salinity sensor corrects for the current temperature reading (sensor in same module as conductivity cell), and calculates salinity. The temperature- and gain-compensated pressure transducer is read by the PIC’s 10-bit A/D converter, and 10 samples are averaged to reduce the effect of power-line noise from the switching voltage regulator. The sensor for light (photosynthetically active radiation [PAR]) is the TAOS TCS230, which measures light intensity in several bands. Light is collected by a spherical Teflon diffuser and conducted to the sensor by a graded-index light fiber (Fujitsu) bundle. The mimic program weights the response in each band such that the aggregate curve is as flat as possible between 400 and 700 nm. Geographical position fixes are obtained during brief surface intervals. A Garmin GPS receiver engine relays position data to the microcontroller’s secondary serial port. The PIC uses the satellite time data to update the system clock to the exact second and logs a good position fix. Before sinking back to “playing organism,” the instrument transmits its current position over the radio beacon. Data (time, target and observed depth, temperature, PAR, salinity, pump activity, vertical velocity, etc.) are logged into nonvolatile serial electronically erasable programmable read-only memory.
The basis of the pressure housing remains a fire extinguisher cylinder; these are inexpensive, readily available, and of almost exactly the right characteristics for 100 m maximum depth. The two halves meet in a PVC ring with o-ring seals. The module containing the IR communications port, temperature sensor, and salinity sensor is part of this mating ring. A plug that screws into the neck of the cylinder incorporates the radio beacon, 32 KHz tracking/telemetry pinger, pressure sensor tube, light collector/fiber, and GPS antenna/cable. The variable ballast (buoyancy adjusting) system uses vinyl ballast bags and ethylene glycol (antifreeze—noncorrosive and with some lubricity) as the ballast fluid. Using parameters determined empirically in a lab tank, the unit maintains programmed depths within 10 cm.
Successful deployments in tethered mode demonstrated that the physiological/behavioral program effectively modulated KBPM vertical migration in response to external environmental and internal cellular cues. Successful deployments on the west Florida shelf demonstrated that KBPM can be deployed in free mode, programmed to undergo vertical migrations, and recovered.
Physical/Biological Model
The physiological/behavioral program was also included in a numerical model. The physical/biological model predicts the alongshore independent development of a K. brevis population over a continental shelf in the presence of a steady wind-driven circulation and specified nutrient fields. The model is intended to predict bloom initiation and development. The key assumption is that the vertical swimming behavior of a cell is determined by the internal carbon and nitrogen content of the cell, its short- and long-term light exposure histories, and the local nutrient and light fields in which it finds itself.
Conclusions
KBPMs provide a cost-effective means of realistically studying the initiation, growth, maintenance, and dissipation of K. brevis blooms. At a cost of $1000 per unit, replicate deployments with different sets of KBPM programmed with alternate behaviors are practical. The controlling KBPM program drives a representative vertical migration based on both external environmental cues (light, temperature, salinity, depth) and internal cellular state (carbon pool fullness regulated by photosynthesis and respiration; nitrogen pool fullness regulated by nutrient uptake capacity and nutrient availability). Deployment duration exceeds 2 weeks with depth capability to 200 m. Recovery is facilitated by an internal pinger, RF transmitter and GPS. Application to other harmful algal bloom species merely requires an appropriate physiological/behavioral program.
Journal Articles on this Report : 9 Displayed | Download in RIS Format
| Other project views: | All 39 publications | 11 publications in selected types | All 10 journal articles |
|---|
| Type | Citation | ||
|---|---|---|---|
|
|
Janowitz GS, Kamykowski D. Modeled Karenia brevis accumulation in the vicinity of a coastal nutrient front. Marine Ecology Progress Series 2006;314:49-59. |
R829370 (Final) |
Exit Exit |
|
|
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 |
|
|
McKay L, Kamykowski D, Milligan E, Schaeffer B, Sinclair G. Comparison of swimming speed and photophysiological responses to different external conditions among three Karenia brevis strains. Harmful Algae 2006;5(6):623-636. |
R829370 (2004) R829370 (Final) |
Exit Exit Exit |
|
|
Nagai T, Yamazaki H, Kamykowski D. A Lagrangian photoresponse model coupled with 2nd-order turbulence closure. Marine Ecology Progress Series 2003;265:17-30. |
R829370 (2003) R829370 (2004) R829370 (Final) |
Exit Exit |
|
|
Schaeffer B, Kamykowski D, Sinclair G, McKay L, Milligan E. Diel vertical migration thresholds of Karenia brevis (Dinophyceae). HARMFUL ALGAE 2009;8(5):692-698. |
R829370 (Final) |
Exit Exit |
|
|
Schaeffer B, Kamykowski D, McKay L, Sinclair G, Milligan E. Lipid Class, Carotenoid, and Toxin Dynamics of Karenia Brevis (Dinophyceae) During Diel Vertical Migration. JOURNAL OF PHYCOLOGY 2009;45(1):154-163. |
R829370 (Final) |
Exit Exit |
|
|
Sinclair GA, Kamykowski D. The effects of physiology and behaviour on the near-bottom distributions of Karenia brevis on the west Florida shelf: a numerical study. African Journal of Marine Science 2006;28(2):361-364. |
R829370 (Final) |
Exit |
|
|
Sinclair G, Kamykowski D, Gilbert P. Growth, uptake, and assimilation of ammonium, nitrate, and urea, by three strains of Karenia brevis grown under low light. HARMFUL ALGAE 2009;8(5):770-780. |
R829370 (Final) |
Exit Exit |
|
|
Waters L, Wolcott T, Kamykowski D, Sinclair G. Deep-water seed populations for red tide blooms in the Gulf of Mexico. MARINE ECOLOGY PROGRESS SERIES 2015;529:1-16 |
R829370 (Final) |
Exit Exit |
Supplemental Keywords:
marine, ecology, environmental chemistry, physics, organism, measurement methods, modeling, algal blooms,, 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.