Digital library

In the tropics, algal turfs are a key marine community, floristically and ecologically, yet the turf structure and its spatial and temporal variation have seldom been quantitatively assessed. We compared species composition and abundance of turf algae on two shallow subtidal reefs (< 2 m deep) on the island of Hawai‘i from September 2000 to July 2002. Of the 102 species of marine algae identified in the algal turf community, 17 belonged to the Chlorophyta, 9 to the Phaeophyta, and 76 to the Rhodophyta. Red algae dominated the turfs at both sites. Species richness, species diversity, and evenness varied between sites and among sampling dates, perhaps due to differences in substratum, precipitation and wave exposure. The most abundant turf species (Ceramium macilentum J. Agardh, Pterocladiella caerulescens (Kützing) Santelices et Hommersand, Hypnea spinella (C. Agardh) Kützing, Coelothrix irregularis (Harvey) Børgesen, Amansia glomerata C. Agardh and Laurencia brachyclados Pilger) showed very patchy spatial distributions and variable seasonal abundances. 38 new records for the island of Hawai‘i were documented, many of which were common. Although growth form rather than dominant or diagnostic species defines the algal turf community, identification and monitoring of individual species, which have different reproductive and physiological characteristics, are essential to understanding the ecology of the turf.

Asparagopsis taxiformis (Asparagopsis) inhibits the production of enteric methane in ruminants. A next critical step in the implementation of this technology is the delivery of a naturally-derived product that maximises the concentration and longer-term retention of bromoform. This study (1) quantified the effects of solvent (water or oil), initial processing (intact or homogenised), and temperature (4 or 25 °C) on the stabilisation of bromoform over time, and (2) assessed the effects of increasing the biomass loading (g biomass mL−1 solvent) of Asparagopsis on the concentration of bromoform in a formulation. The most effective method was to homogenise freshly-collected Asparagopsis in oil, which resulted in the highest concentration of bromoform (19.2 ± 2.1 mg g−1 dw algae) in the homogeneous product in the shortest time (one day). In addition, the final product had a shelf life of at least 12 weeks, even when stored at room temperature (25 °C). Notably, there was an increase in the concentration of bromoform per mL of oil between each increment of biomass loading tested, with the highest concentration of bromoform of 4.04 ± 0.51 mg mL−1 in the maximum ratio of biomass to oil of 120 g 100 mL−1. The method described here provides a viable processing alternative to freeze-drying, resulting in the stabilisation of the bromoform from Asparagopsis, which will be critical to the success of using Asparagopsis on a larger scale to mitigate the production of methane in ruminants. 

The effects of plant growth regulators on callus induction rate and regeneration of K. alvarezii explants was evaluated.K. alvarezii calluses were induced in vitro with kinetin (K), 6benzylaminopurine (B), 1-naphtalene acetic acid (N) and spermine (S). After 30 days, K. alvarezii explants produced filamentous calluses and isolated crystalline filaments growing from the medullar region and from cortical cells at the cut edge. The plant growth regulators 1-naphtalene acetic acid (1 mg L−1) and 6-benzylaminopurine (1 mg L−1) and the 1-naphtalene acetic acid + kinetin + spermine (1, 1, 0.018 mg L−1 respectively) combination produced 85 to 129% more calluses, with significant differences versus the control (p < 0.05). Spermine at 0.018 mg L−1 produced calluses in the apical, intercalary and basal regions of explants. Spermine also reduced callus induction time to 7 days, which is faster than previously reported induction times with other plant growth regulators. An airlift bioreactor was designed and characterized to micropropagate K. alvarezii calluses. The bioreactor had mixing times ranging from 4.6–10.3 s at T90 and T95, which is shorter than those for the Fernbach (5.2–13.4 s) and balloon flasks (6.3–17.3 s). Mixing time standard deviations were smaller for the bioreactor (1.1–4.6) than for the Fernbach (9.3–13.6) and balloon flasks (5.5–15.8), suggesting an adequate flow regime within the bioreactor. The results are useful for improving callus induction in K. alvarezii and propagating microplantlets in an airlift bioreactor, and provide baseline data for macroalgal bioreactor culture

The coast of Jiangsu Province in China e where Ulva prolifera has always been firstly spotted before developing into green tides e is uniquely characterized by a huge intertidal radial mudflat. Results showed that: (1) propagules of U. prolifera have been consistently present in seawater and sediments of this mudflat and varied with locations and seasons; (2) over 50,000 tons of fermented chicken manure have been applied annually from March to May in coastal animal aquaculture ponds and thereafter the waste water has been discharged into the radial mudflat intensifying eutrophication; and (3) freefloating U. prolifera could be stranded in any floating infrastructures in coastal waters including large scale Porphyra farming rafts. For a truly integrated management of the coastal zone, reduction in nutrient inputs, and control of the effluents of the coastal pond systems, are needed to control eutrophication and prevent green tides in the future.