Field and laboratory studies on the effect of particle size and composition on optical backscattering measurements in hydrothermal plumes

Abstract We describe the performance of an inexpensive but highly sensitive light backscattering sensor (LBSS) suitable for use in deep-sea waters, where particle concentrations are typically 10 μm. Field studies indicate that in hydrothermal plumes dominated by fine-grained metal precipitates the 95% confidence interval for predicting mass concentration with an LBSS ranges from ±0.004 mg/l for 0.03 mg/l suspensions to ±0.008 mg/l at 0.12 mg/l. Comparisons among a group of 19 LBSSs found between-instrument variability to reach 70%, but normalizing the raw data using a laboratory calibration procedure reduced the maximum variability to ∼8%.

[1]  J. Moody,et al.  Near-bottom suspended matter concentration on the Continental Shelf during storms: estimates based on in situ observations of light transmission and a particle size dependent transmissometer calibration , 1987 .

[2]  H. Pak,et al.  LIGHT‐SCATTERING VECTORS OF SOME MARINE PARTICLES1 , 1970 .

[3]  J. Zaneveld,et al.  Intermediate Nepheloid Layers Observed off Oregon and Washington , 1980 .

[4]  R. Feely,et al.  Seafloor eruptions and evolution of hydrothermal fluid chemistry , 1997, Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[5]  James K. B. Bishop,et al.  The correction and suspended particulate matter calibration of Sea Tech transmissometer data , 1986 .

[6]  R. Gibbs.  Light scattering from particles of different shapes , 1978 .

[7]  C. Tropea,et al.  Light Scattering from Small Particles , 2003 .

[8]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[9]  W. Gardner.  Baltimore Canyon as a modern conduit of sediment to the deep sea , 1989 .

[10]  C. Wirsen,et al.  Microbiology and Ecology of Filamentous Sulfur Formation , 1997 .

[11]  Dariusz Stramski,et al.  Effects of microbial particles on oceanic optics: A database of single‐particle optical properties , 1997 .

[12]  E. Baker,et al.  In situ observations of the onset of hydrothermal discharge during the 1998 Submarine Eruption of Axial Volcano, Juan de Fuca Ridge , 1999 .

[13]  R. Hogg,et al.  Estimation of particle size distributions from turbidimetric measurements , 1979 .

[14]  Richard D. Vanous,et al.  5 – THE THEORY AND MEASUREMENT OF TURBIDITY AND RESIDUE , 1982 .

[15]  P. Ridd,et al.  Biofouling control for optical backscatter suspended sediment sensors , 1994 .

[16]  John P. Downing,et al.  Laboratory apparatus for calibrating optical suspended solids sensors , 1989 .

[17]  Dale A. Kiefer,et al.  Light scattering by microorganisms in the open ocean , 1991 .

[18]  E. Baker,et al.  Particle-size distributions within hydrothermal plumes over the Juan de Fuca Ridge , 1988 .

[19]  E. Baker.  Patterns of suspended particle distribution and transport in a large fjordlike estuary , 1984 .

[20]  E. Baker,et al.  Hydrothermal plumes along the East Pacific Rise, 8°40′ to 11°50′N: Particle distribution and composition , 1994 .

[21]  André Morel,et al.  Optics of heterotrophic nanoflagellates and ciliates : a tentative assessment of their scattering role in oceanic waters compared to those of bacterial and algal cells , 1991 .

[22]  E. Baker,et al.  The effect of particle size on the light attenuation coefficient of natural suspensions , 1984 .

[23]  E. Baker,et al.  Evidence for iron and sulfur enrichments in hydrothermal plumes at Axial Volcano following the January–February 1998 eruption , 1999 .

[24]  H. Edmonds,et al.  Evolution of East Pacific Rise hydrothermal vent fluids following a volcanic eruption , 1995, Nature.