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We evaluated models predicting the spectral chlorophyll-a (Chl a)-specific absorption coefficient (a* ph (λ)) from Chl a concentration [Chl a] on the basis of 465 phytoplankton absorption spectra collected in estuarine, coastal and oceanic waters. A power model on ln-transformed data provided the best model fit compared to a power model on non-transformed data previously applied to parameterize the relationship between a* ph (λ) and [Chl a]. The variation in a* ph (λ) was parameterized over four orders of magnitude in [Chl a] (0.01-100 mg Chl a m−3) producing a 13-fold range in a* ph (0.19 to 0.015 m2 mg−1 Chl a) at 440 nm, the peak absorption of Chl a in the blue part of the spectrum. The variations in the modelled a* ph spectra were within realistic predictions of a* ph (λ) and the model satisfactorily reproduced the spectral flattening with increasing [Chl a]. The parameterization of a* ph (λ) confirmed the indirect dependency of a* ph (λ) on [Chl a] through co-variations between [Chl a] with pigment p...

We have tested the importance of thallus thickness in marine macroalgae for the growth-irradiance relationship measured in the laboratory and for the maximum growth rate measured in the field. We found large differences in the growth-irradiance relationship depending on the biomass parameter (surface area, fresh weight, carbon content) applied. Use of carbon content yielded meaningful reproducible patterns and it appeared to be the most suitable descriptor of plant energetics. Surface area and fresh weight increased in the dark despite loss of carbon in the plant tissue. The growth kinetic parameters were closely related to thallus thickness, here described as thallus-specific carbon (TSC, mol tissue C m−2 surface area). Both the loss rates in the dark and the growth rates in carbon biomass at low and high irradiance decreased with increasing TSC of the species. The decline in growth rate with increasing TSC was described by the allometric equation log(growth rate) = a + b × log(TSC). The slope, b, was be...

Practical guidelines for the analysis of seawater Edited by Oliver Wurl Boca Raton, FL, CRC Press, Taylor & Francis Group, 2009, 401 pp., ISBN 978-1420073065. US$ 149.95 (hardback) The title promis...