Stanislaus Sonnenholzner

Technical potential of microalgal bacterial floc raceway ponds treating food-industry effluents while producing microalgal bacterial biomass : an outdoor pilot-scale study

To replace costly mechanical aeration by photosynthetical aeration, upflow anaerobic sludge blanket (UASB) effluent of food-industry was treated in an outdoor MaB-floc raceway pond. Photosynthetic aeration was sufficient for nitrification, but the raceway effluent quality was below current discharge limits, despite the high hydraulic retention time (HRT) of 35days. Hereafter, conventional activated sludge (CAS) effluent of food-industry was treated in this pond to recover phosphorus. The two-day HRT results in a more realistic pond area, but the phosphorus removal efficiency was low (20%). High biomass productivities were obtained, i.e. 31.3 and 24.9ton total suspended solids hapond(-1)year(-1) for UASB and CAS effluent, respectively. Bioflocculation enabled successful harvesting of CAS effluent-fed MaB-flocs by settling and filtering at 150-250μm to 22.7% total solids. To conclude, MaB-floc raceway ponds cannot be recommended as the sole treatment for these food-industry effluents, but huge potential lies in added-value biomass production.

Broodstock Conditioning, Spawning Induction, and Early Larval Development of the Tropical Rock Oyster Striostrea prismatica (Gray 1825)

ABSTRACT The tropical rock oyster Striostrea prismatica is a commercially valuable bivalve mollusc found along the Pacific tropical coast. A laboratory study was conducted to investigate broodstock acclimation at two temperatures (28.3 ± 0.9°C and 22.2 ± 0.9°C) fed a combined microalgae diet (Chaetoceros gracilis and Isochrysis galbana at 150 cells/µL/day and 100 cells/µL/ day, respectively) for 7 wk, and to investigate seven treatments to stimulate spawning of individuals acclimated at both temperatures. Treatments to induce spawning consisted of a 10°C temperature decrease for 60 min (HS1), a temperature increase to 30°C for 30 min (HS2), a 5°C temperature increase for 60 min followed by 30 min of desiccation (HSD), a decrease in salinity to 15 psu for 30 min (SS1), an increase in salinity to 96 psu for 30 min (SS2), overfeeding with C. gracilis microalgae (OF), and the addition of oyster sperm (SPM). All treatments were treated with oyster sperm after 1 h of the last stimulus. Spawning success was evaluated by measuring egg production, fertilization percentage, and response time of spawning. Only broodstock held at 28°C spawned (51.8%). All organisms in the HSD treatment spawned after 1.40 ± 1.01 h. Oocytes released per individual and fertilization rate averaged 34.88 ± 23.81×106 and 89.82 ± 5.90%, respectively. Addition of sperm enhanced spawning success in the HS1, HS2, and SS1 treatments.

Spondylids of Eastern Pacific Ocean

ABSTRACT Members of the bivalve molluscan family Spondylidae were very important elements in the world view of pre-Hispanic cultures of America, and today remain as symbols of culture heritage in contemporary society. In recent decades, given the importance they have for crafts and jewelry, as well as for fisheries and gastronomy, their exploitation has caused a drastic decrease in natural populations leading to restrictions in fishing. In the present review, data about Spondylus species of eastern Pacific Ocean, describing the symbolism, taxonomy, distribution, biology, and ecology, their status as exploitable resources, the advances in aquaculture of these species, as well as management experiences and conservation efforts are presented.

Microalgal bacterial flocs treating paper mill effluent: A sunlight-based approach for removing carbon, nitrogen, phosphorus, and calcium

Treatment of upflow anaerobic sludge blanket (UASB) effluent from a paper mill in aerated activated sludge reactors involves high aeration costs. Moreover, this calcium-rich effluent leads to problematic scale formation. Therefore, a novel strategy for the aerobic treatment of paper mill UASB effluent in microalgal bacterial floc sequencing batch reactors (MaB-floc SBRs) is proposed, in which oxygen is provided via photosynthesis, and calcium is removed via bio-mineralization. Based on the results of batch experiments in the course of this study, a MaB-floc SBR was operated at an initial neutral pH. This SBR removed 58±21% organic carbon, 27±8% inorganic carbon, 77±5% nitrogen, 73±2% phosphorus, and 27±11% calcium. MaB-flocs contained 10±3% calcium, including biologically-influenced calcite crystals. The removal of calcium and inorganic carbon by MaB-flocs significantly decreased when inhibiting extracellular carbonic anhydrase (CA), an enzyme that catalyses the hydration and dehydration of CO2. This study demonstrates the potential of MaB-floc SBRs for the alternative treatment of calcium-rich paper mill effluent, and highlights the importance of extracellular CA in this treatment process.

Spat Production of the Rock Oyster Striostrea prismatica (Gray, 1825)

ABSTRACT The rock oyster Striostrea prismatica is one of the most abundant species in the rocky coastal ecosystems of the tropical and subtropical eastern Pacific; however, natural banks are overexploited or depleted, so production by culture is recommended. Adult S. prismatica obtained from natural banks were conditioned for gonad maturation and spawning. Fertilization, embryogenic, and larval development were performed under laboratory conditions, then settlement of pediveliger larvae and nursing of postlarvae were performed using downwelling methods to produce spat. The early life cycle (embryonic, larval, and postlarval development up to 5 mm in length) is described. The larval development was completed in 22 days, with survival >25%. The larval and postlarval growths were exponential reaching spat size (5 mm) after 28 days of settlement. The methods used in this study supported successful larval and postlarval culture of S. prismatica and provide a basis for large-scale propagation of this species.