Spectrophotometry of Translucent Biological Materials—Opal Glass Transmission Method

Shibata, Kazuo

doi:10.1002/9780470110232.ch3

Cited by 108 publications

(19 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Diffuse illumination was provided from light reflected from a semisphere coated with barium oxide (BaO) illuminated was with a white LED ring (450-650 nm) located around the sample, plus violet-blue LEDs and halogen lamps, to increase the diffuse illumination below 450 nm and above 650 nm (Vásquez-Elizondo et al, 2017). Transmission spectra were determined as T L (λ) = 10 −D(λ) , where D(λ) denotes absorbance, using a conventional spectrophotometer (AMINCO DW2, USA) controlled by an OLIS data collection system equipped with an opal-glass in front of the detector, following the methodology proposed by Shibata (1959) and described in Enríquez (2005) and Vásquez-Elizondo et al (2017). Absorptance estimations were calculated as…”

Section: Canopy Reflectance Modelmentioning

confidence: 99%

Remote Sensing of Seagrass Leaf Area Index and Species: The Capability of a Model Inversion Method Assessed by Sensitivity Analysis and Hyperspectral Data of Florida Bay

Hedley¹,

Russell

Randolph

et al. 2017

Front. Mar. Sci.

View full text Add to dashboard Cite

The capability for mapping two species of seagrass, Thalassia testudinium and Syringodium filiforme, by remote sensing using a physics based model inversion method was investigated. The model was based on a three-dimensional canopy model combined with a model for the overlying water column. The model included uncertainty propagation based on variation in leaf reflectances, canopy structure, water column properties, and the air-water interface. The uncertainty propagation enabled both a-priori predictive sensitivity analysis of potential capability and the generation of per-pixel error bars when applied to imagery. A primary aim of the work was to compare the sensitivity analysis to results achieved in a practical application using airborne hyperspectral data, to gain insight on the validity of sensitivity analyses in general. Results showed that while the sensitivity analysis predicted a weak but positive discrimination capability for species, in a practical application the relevant spectral differences were extremely small compared to discrepancies in the radiometric alignment of the model with the imagery-even though this alignment was very good. Complex interactions between spectral matching and uncertainty propagation also introduced biases. Ability to discriminate LAI was good, and comparable to previously published methods using different approaches. The main limitation in this respect was spatial alignment with the imagery with in situ data, which was heterogeneous on scales of a few meters. The results provide insight on the limitations of physics based inversion methods and seagrass mapping in general. Complex models can degrade unpredictably when radiometric alignment of the model and imagery is not perfect and incorporating uncertainties can have non-intuitive impacts on method performance. Sensitivity analyses are upper bounds to practical Hedley et al.Remote Sensing of Seagrasses capability, incorporating a term for potential systematic errors in radiometric alignment may be advisable. While T. testudinium and S. filiforme were too spectrally similar to be discriminated purely on spectral grounds, mapping of these, and other species may be achievable by exploiting co-incident factors based on ecological zonation.

show abstract

Section: Canopy Reflectance Modelmentioning

confidence: 99%

Remote Sensing of Seagrass Leaf Area Index and Species: The Capability of a Model Inversion Method Assessed by Sensitivity Analysis and Hyperspectral Data of Florida Bay

Hedley¹,

Russell

Randolph

et al. 2017

Front. Mar. Sci.

View full text Add to dashboard Cite

show abstract

“…Determinations of light transmission (Absorbance, D) were performed using a spectrophotometer AMINCO DW2 (USA) controlled by an OLIS data collection system, equipped with an opal-glass in front of the detector (Shibata, 1959). Thallus fragments were mounted in a 3 ml cuvette, filled with filtered seawater.…”

Section: Optical Determinationsmentioning

confidence: 99%

Light Absorption in Coralline Algae (Rhodophyta): A Morphological and Functional Approach to Understanding Species Distribution in a Coral Reef Lagoon

Vásquez-Elizondo

Enríquez

2017

Front. Mar. Sci.

View full text Add to dashboard Cite

Red coralline algae are a cosmopolitan group with the ability to precipitate CaCO 3 within the walls of their vegetative cells. The resultant carbonate structure is key for explaining their ecological success, as it provides protection against herbivores and resistance to water motion. However, its potential contribution to enhance thallus light absorption efficiency through multiple light scattering on algal skeleton, similar to the effect documented for scleractinian corals, has not been yet investigated. Here, we initiate this analysis, characterizing thallus optical properties of three coralline species, which differed in pigment content and thallus mass area (TMA, gDW m −2 ). The three species, the rhodolith Neogoniolithon sp., the crustose coralline alga (CCA), Lithothamnion sp., and the articulated alga Amphiroa tribulus, represent the more distinctive coralline growth-forms and are able to colonize contrasting light environments in Caribbean coral reefs. The thicker thalli of the rhodoliths were the most efficient light collectors, as evidenced by their higher pigment absorption efficiency (a * Chla ; m 2 mgChla −1 ) and photosynthetic rates per unit area. This could explain rhodolith success in oligotrophic, highly illuminated reef environments. In contrast, the thinner thalli of the CCA, a low-light specialist, showed the highest metabolic rates normalized to mass and the highest light absorption efficiencies per unit mass (a * M ; m 2 gdw −1 ). Therefore, the ecological success of the CCA in cryptic habitats within the reef cannot be explained only by its low-light physiology, but also by its capacity to reduce the structural costs of their thalli, and thus of its new growth. Lastly, the ecological success of Amphiroa tribulus, which displayed intermediate values for the efficiency of light absorption, metabolic rates and TMA, was explained by its ability to construct the largest light collectors (algal canopies) thanks to the presence of flexible, non-calcified segments (genicula). This ability enables enhanced photosynthetic and carbonate production at the organism/canopy level. The resulting fragile canopy survives best within the protection provided by colonies of the lettuce coral Agaricia agaricites. In conclusion, our study demonstrates the utility of optical traits as powerful tools to investigate differences in the competitive abilities, abundances and niche distribution among algal species and/or growth-forms.

show abstract

“…Optical properties of algal thalli-Light absorption was measured using the opal-glass technique, developed for intact leaves by Shibata (1959) and successfully applied in aquatic macrophyte tissues (Enríquez et al 1994;Enríquez and Sand-Jensen 2003;Enríquez 2005). Thallus fragments were mounted into 3-mL cuvettes filled with filtered seawater.…”

Section: Methodsmentioning

confidence: 99%

Is the photo‐acclimatory response of Rhodophyta conditioned by the species carotenoid profile?

Schubert

García‐Mendoza

Enríquez

2011

Limnology & Oceanography

View full text Add to dashboard Cite

The success of Rhodophyta in coastal areas is largely determined by their capacity to withstand high-light conditions. To understand the photo-acclimatory response of Rhodophyta, we compared differences in pigmentation, light absorption, and changes in the chlorophyll a fluorescence signal between apical and basal thalli of Eucheuma isiforme, a lutein-predominant species, and Gracilaria damaecornis, a zeaxanthin-predominant species. Variation in the fluorescence signal was characterized after exposure of basal and apical segments of each species to five saturating light levels, and monitoring of the subsequent recovery in the absence and presence of chloramphenicol, an inhibitor of the photosystem II (PSII) repair mechanism. Our results confirm that Rhodophyta is a highly diverse algal group with respect to antenna composition and photoprotective mechanisms. The permanent activation of an energy quencher in the zeaxanthin-predominant species requires switching to antheraxanthin in the low-light response and higher dependence on PSII repair. No such quencher was detected in the lutein-predominant species, which showed no change in relative carotenoid composition, slight differences between apical and basal thalli in PSII pressure, and less dependence on PSII repair. It remains unclear if the combined presence of lutein-zeaxanthin allows effective photoprotection or if other mechanisms (i.e., phycobilisome quenching) may explain the effective photoprotective response shown by E. isiforme. The differences highlighted in this comparison may contribute to explain the distribution and abundance of Rhodophyta in marine coastal areas through understanding differences within the group in their ability to protect the photosynthetic apparatus from absorbing light in excess, and in the metabolic costs of PSII repair.

show abstract

Spectrophotometry of Translucent Biological Materials—Opal Glass Transmission Method

Cited by 108 publications

References 50 publications

Remote Sensing of Seagrass Leaf Area Index and Species: The Capability of a Model Inversion Method Assessed by Sensitivity Analysis and Hyperspectral Data of Florida Bay

Remote Sensing of Seagrass Leaf Area Index and Species: The Capability of a Model Inversion Method Assessed by Sensitivity Analysis and Hyperspectral Data of Florida Bay

Light Absorption in Coralline Algae (Rhodophyta): A Morphological and Functional Approach to Understanding Species Distribution in a Coral Reef Lagoon

Is the photo‐acclimatory response of Rhodophyta conditioned by the species carotenoid profile?

Contact Info

Product

Resources

About