Minimum spectral light requirements and maximum light levels for long-term germling growth of several red algae from different water depths and a green alga

Abstract

Spores and germlings of six red algal species were cultivated for 15 weeks in coloured light fields at low intensities. The photon fluence rates at which growth exceeded growth in dark-kept controls were, in green light, 0-1 #mol m-2s -1 in Audouinella daviesii, 0.5 #mol m-2s -1 in Halarachnion ligalatum, Pterothamnion plumula, Chondrus crispus and Plumaria elegans, and I'0/~mol m-2s -~ in Ceramium rubrum. In blue or red light, at least 1-0 #mol m-2s -1 was required for germling growth in these species, except for P. elegans which required 0"5 #mol m-Zs -I in blue light. The advantage of green light for growth was particularly evident in A. daviesii which formed no more than two cells in darkness and in photon fluence rates up to 1 #tool m-Zs -~ of blue or red, but one further cell after 15 weeks at 0"1 #mol m-2s -1 in green. Germling growth of the green alga Ulva pseudocurvata required at least 3/zmol m-2s -1 in green, but only 1"0/zmol m-2s -1 in blue or red light. White fluorescent light levels permitting growth in red algae were higher than those in green light and equal to minimum requirements in blue or red light in the majority of species investigated. Settled spores of H. ligulatum and the green alga Chaetomorpha melagonium survived for at least 1 year in darkness, whereas spores of C. crispus survived only 39 weeks and those of 11 other red algae and U. pseudocurvata survived 26 weeks or less. Light saturation and light inhibition of growth occurred at higher photon fluence rates in the lower eulittoral species Ceramium rubrum, C. crispus and U. pseudocurvata (saturation, 200-300 #tool m-2s-1; inhibition, 300-500/zmol m-2s -1) than in the strictly sublittoral species H ligulatum and P, plumula (saturation, 10-20 #mol m-2s-~; inhibition, 50-100 #mol m-2s-1).

Survival in low light: photosynthesis and growth of a red alga in relation to measured in situ irradiance

“…). While our estimates for A. crinitum are somewhat lower than previously published results, given the good agreement between two separate lines of evidence (i.e., photosynthesis and growth experiments) and that the minimum daily light requirements of some rhodophyte macroalgae can be very low (0.01–0.03 mol photons · m −2 · d −1 ; Leukart and Lüning ) it seems likely that the these minimum daily light requirements for A. crinitum are realistic. Collectively these low minimum light requirements for photosynthesis and growth suggest that A. crinitum is well adapted to harvesting low incident light and supports our conclusion that A. crinitum is a highly shade tolerant species and a functional analog of rhodophyte algae in other deep‐water or low light habitats.…”

“…Existing syntheses of experimentally derived physiological data, observed maximum depth limits and light attenuation coefficients suggest that minimum daily light requirements for macroalgal growth must lie somewhere between 0.0001 (crustose coralline algae) and 4.42 mol photons Á m À2 Á d À1 (Valonia ventricosa, Chlorophyta; Littler et al 1986, L€ uning 1990, Markager and Sand-Jensen 1992, Spalding et al 2003, Gattuso et al 2006, Kirk 2011, with the minimum light requirements for non-calcareous rhodophyte macroalgae near 0.91 mol photons Á m À2 Á d À1 (Gattuso et al 2006). While our estimates for A. crinitum are somewhat lower than previously published results, given the good agreement between two separate lines of evidence (i.e., photosynthesis and growth experiments) and that the minimum daily light requirements of some rhodophyte macroalgae can be very low (0.01-0.03 mol photons Á m À2 Á d À1 ; Leukart and L€ uning 1994) it seems likely that the these minimum daily light requirements for A. crinitum are realistic. Collectively these low minimum light requirements for Letters denote significant differences between light levels and asterisks denote a significant difference compared to initial values.…”

Dissolved oxygen dynamics under ice: Three winters of high‐frequency data from Lake Tovel, Italy

“…In Lake Tovel, algal biomass is low [ Cellamare et al ., ], and most of the phytoplankton community is composed of mixotrophs (chrysophytes, cryptomonads, and dinoflagellates) and osmotrophs (diatoms) that are adapted to low light and cold temperatures [ Flaim et al ., ; Cellamare et al ., ]. While under‐ice PAR intensity at 5 m was low (mean = 7.4 µmol photons m −2 s −1 ; median = 1.8), these observed low light intensities were within the range that enables photosynthetic activity in algae adapted to deep waters [see Leukart and Lüning , ; Gomez et al ., ]. Thus, assuming photosynthetic activity under ice seemed reasonable and probably occurred at a higher rate above a depth of 5 m.…”

Effect of Different Light Qualities on Growth, Pigment Content, Chlorophyll Fluorescence, and Antioxidant Enzyme Activity in the Red AlgaPyropia haitanensis(Bangiales, Rhodophyta)

“…Similarly, some studies have shown that B and G light could play an advantageous role on red algae growth and their development [19]. Moreover, Pearson et al [20] reported that Silvetia compressa releases gametes during B or in low R/B light ratios exposure, showing significant influences of light wavelength on algal growth.…”