title: In situ applications of a new diver-operated motorized microsensor profiler.
abstract: Microsensors are powerful tools for microenvironment studies, however their use has often been restricted to laboratory applications due to the lack of adequate equipment for in situ deployments. Here we report on new features, construction details, and examples of applications of an improved diver-operated motorized microsensor profiler for underwater field operation to a water depth of 25 m. The new motorized profiler has a final precision of 5 microm, and can accommodate amperometric Clark-type microsensors for oxygen and hydrogen sulfide, potentiometric microsensors (e.g., for pH, Ca2+), and fiber-optic irradiance microsensors. The profiler is interfaced by a logger with a signal display, and has pushbuttons for underwater operation. The system can be pre-programmed to autonomous operation or interactively operated by divers. Internal batteries supply power for up to 24 h of measurements and 36 h of data storage (max. 64 million data points). Two flexible stands were developed for deployment on uneven or fragile surfaces, such as coral reefs. Three experimental pilot studies are presented, where (1) the oxygen distribution in a sand ripple was 3-D-mapped, (2) the microenvironment of sediment accumulated on a stony coral was studied, and (3) oxygen dynamics during an experimental sedimentation were investigated. This system allows SCUBA divers to perform a wide array of in situ measurements, with deployment precision and duration similar to those possible in the laboratory.
authors.affiliation: Max-Planck-Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany. m.weber@hydra-institute.com
authors.forename: Miriam
authors.initials: M
authors.lastname: Weber
authors.forename: Paul
authors.initials: P
authors.lastname: Faerber
authors.forename: Volker
authors.initials: V
authors.lastname: Meyer
authors.forename: Christian
authors.initials: C
authors.lastname: Lott
authors.forename: Gabriele
authors.initials: G
authors.lastname: Eickert
authors.forename: Katharina E
authors.initials: KE
authors.lastname: Fabricius
authors.forename: Dirk
authors.initials: D
authors.lastname: De Beer
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000502:physiology; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002118:Calcium / Q000032:analysis; D002413:Cations, Divalent; D004242:Diving; D004563:Electrochemistry; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D005336:Fiber Optic Technology; D019015:Geologic Sediments / Q000032:analysis; D006801:Humans; D006862:Hydrogen Sulfide / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D016247:Information Storage and Retrieval; D055100:Optical Fibers; D010100:Oxygen / Q000032:analysis; D045483:Rivers; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D002413:Cations, Divalent; D010100:Oxygen; D002118:Calcium; D006862:Hydrogen Sulfide