&lt;title&gt;Scattering error correction of reflecting-tube absorption meters&lt;/title&gt;

Zaneveld, J. Ronald V.; Kitchen, James C.; Moore, C.

doi:10.1117/12.190095

Cited by 239 publications

(215 citation statements)

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“…Absorption data were additionally corrected for scattering losses within the ac9 light path according to the third method of Zaneveld et al (1994), and CDOM absorption was subtracted. SPM concentrations were determined gravimetrically on triplicate, pretared, 0.1-mm pore size, 47-mm-diameter polycarbonate filters (Nucleopore).…”

Section: Methodsmentioning

confidence: 99%

Rate and apparent quantum yield of photodissolution of sedimentary organic matter

Estapa

Mayer

Boss

2012

Limnology & Oceanography

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We quantified rates of photochemical dissolution (photodissolution) of organic carbon in coastal Louisiana suspended sediments, conducting experiments under well-defined conditions of irradiance and temperature. Optical properties of the suspended sediments were characterized and used in a radiative transfer model to compute irradiances within turbid suspensions. Photodissolution rate increased with temperature (T), with activation energy of 32 6 7 kJ mol 21 , which implicates indirect (non-photochemical) steps in the net reaction. In most samples, dissolved organic carbon (DOC) concentration increased approximately linearly with time over the first 4 h of irradiation under broadband simulated sunlight, after higher rates in the initial hour of irradiation. Four-hour rates ranged from 2.3 mmol DOC m 23 s 21 to 3.2 mmol DOC m 23 s 21 , but showed no relation to sample origin within the study area, organic carbon or reducible iron content, or mass-specific absorption coefficient. First-hour rates were higher-from 3.5 mmol DOC m 23 s 21 to 7.8 mmol DOC m 23 s 21 -and correlated well with sediment reducible iron (itself often associated with organic matter). The spectral apparent quantum yield (AQY) for photodissolution was computed by fitting DOC photoproduction rates under different spectral irradiance distributions to corresponding rates of light absorption by particles. The photodissolution AQY magnitude is similar to most published dissolved-phase AQY spectra for dissolved inorganic carbon photoproduction, which suggests that in turbid coastal waters where particles dominate light absorption, DOC photoproduction from particles exceeds photooxidation of DOC.

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Section: Methodsmentioning

confidence: 99%

Rate and apparent quantum yield of photodissolution of sedimentary organic matter

Estapa

Mayer

Boss

2012

Limnology & Oceanography

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“…The contribution of particles to total absorption was assessed as the difference between the unfiltered and filtered values. Temperature and salinity corrections were applied to both absorption and attenuation values [Pegau et al, 1997], and absorption measurements were corrected for scattering errors [Zaneveld et al, 1994]. In addition, the absorption spectra for dissolved material were offset to zero at 676 nm.…”

Section: Methodsmentioning

confidence: 99%

Temporal and vertical variability in optical properties of New England shelf waters during late summer and spring

Sosik¹,

Green²,

Pegau³

et al. 2001

J. Geophys. Res.

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Abstract. Relationships between optical and physical properties were examined on the basis of intensive sampling at a site on the New England continental shelf during late summer 1996 and spring 1997. During both seasons, particles were found to be the primary source of temporal and vertical variability in optical properties since light absorption by dissolved material, though significant in magnitude, was relatively constant. Within the particle pool, changes in phytoplankton were responsible for much of the observed optical variability. Physical processes associated with characteristic seasonal patterns in stratification and mixing contributed to optical variability mostly through effects on phytoplankton. An exception to this generalization occurred during summer as the passage of a hurricane led to a breakdown in stratification and substantial resuspension of nonphytoplankton particulate material. Prior to the hurricane, conditions in summer were highly stratified with subsurface maxima in absorption and scattering coefficients. In spring, stratification was much weaker but increased over the sampling period, and a modest phytoplankton bloom caused surface layer maxima in absorption and scattering coefficients. These seasonal differences in the vertical distribution of inherent optical properties were evident in surface reflectance spectra, which were elevated and shifted toward blue wavelengths in the summer. Some seasonal differences in optical properties, including reflectance spectra, suggest that a significant shift toward a smaller particle size distribution occurred in summer. Shorter timescale optical variability was consistent with a variety of influences including episodic events such as the hurricane, physical processes associated with shelfbreak frontal dynamics, biological processes such as phytoplankton growth, and horizontal patchiness combined with water mass advection.

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“…Depth profiles of inherent optical properties were measured using a dual path, multiband absorption/ attenuation meter (ac-9, WETLabs) and backscattering meters (a-␤eta and HydroScat-2, HOBILabs) at a site 80 km from the coast of Portsmouth, New Hampshire (42Њ47ЈN 70Њ05ЈW, 1106 h local time, 30 June 2000). Measurements were corrected for temperature and salinity, and absorption measurements were corrected for scattering errors (Zaneveld et al 1994;Pegau et al 1997). The backscattering meters were calibrated by the manufacturer, and the ac-9 was calibrated on its deployment frame using water generated with a Milli-Q purification system (Millipore Corp.).…”

Section: Calculation Of Underwater Radiances and Irradiances-mentioning

confidence: 99%

Cryptic coloration and mirrored sides as camouflage strategies in near‐surface pelagic habitats: Implications for foraging and predator avoidance

Johnsen

Sosik

2003

Limnology & Oceanography

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Mirrored and colored surfaces are common adaptations for crypsis in pelagic habitats. Although highly successful when optimized for a particular situation, either may become less successful if it is then viewed in a different situation. In this study we examine the relative robustness of these two strategies by determining how visible an organism becomes when viewed under optical conditions different from those under which the camouflage is optimal. Underwater radiance distributions were calculated using inherent optical properties measured in coastal waters 80 km off the coast of New Hampshire. These radiance distributions were then used to calculate optimally cryptic diffuse and specular reflectance spectra as a function of depth, solar elevation, viewing angle, and azimuth. Then the visibilities of organisms cryptic in one situation viewed in a different situation were calculated, using the Atlantic Cod, Gadus morhua, as the viewer. In contrast to benthic organisms, pelagic organisms cryptic under one set of optical conditions were quite visible under a different set, particularly when viewed from a different azimuth. The crypsis afforded by mirrored surfaces was generally more robust than that resulting from colored surfaces. However, because mirrored surfaces could never be perfectly cryptic when viewed in the azimuth of the sun, neither strategy clearly outperformed the other. In general, crypsis by colored or mirrored surfaces was not robust in nearsurface water, which may help explain both the predominance of transparent species in near-surface pelagic habitats and the vertical migration of many colored and mirrored species. The results also show that three common foraging strategies-circling, crepuscular activity, and driving prey toward the surface-all increase the visibility of cryptically colored or mirrored prey.

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<title>Scattering error correction of reflecting-tube absorption meters</title>

Cited by 239 publications

References 0 publications

Rate and apparent quantum yield of photodissolution of sedimentary organic matter

Rate and apparent quantum yield of photodissolution of sedimentary organic matter

Temporal and vertical variability in optical properties of New England shelf waters during late summer and spring

Cryptic coloration and mirrored sides as camouflage strategies in near‐surface pelagic habitats: Implications for foraging and predator avoidance

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