Algal-derived therapeutics, bioactive molecules, and fuels produced in photobioreactors (PBRs) are of great scientific and economic interest, but the high cost of production still prevents their widespread use. Specifically, the cost of the energy inputs and the control of the photonic inputs that enable production optimization continue to be problematic. To this end, a novel 55-L annular-plate airlift PBR (APAPBR) with internal illumination was designed and characterized for the batch production of algal biomass. The APAPBR was able to convert mixing and photonic energy inputs into Chlorella pituita SG1 biomass at an efficiency of 0.064 (J biomass [J input] −1 ), or 0.27 g dry cell weight (DW) W −1 d −1 . Thanks to a high degree of photon capture and the airlift effect that provided energy-efficient mixing and mass transfer, this energy conversion is 54% of the theoretical maximum as determined in previous studies. Under these efficiency conditions, C. pituita SG1 was able to grow photoautotrophically to 3.9 ± 0.2 gDW L −1 . Additionally, a mathematical approach was used to predict the mean light intensity with the highest biomass yield per unit of photonic input and the maximum biomass concentration achievable under the given process conditions. These predictions were validated in our system by the experimental cultivation data. This APAPBR represents a simple, innovative, and energy-efficient PBR configuration that could decrease the cost of phototrophic bioprocesses and enable novel bioprocesses that require a high degree of control over the photonic input.

Acuña et al.: Fish assemblage in Uruguayan subestuaries 173Inter-estuarine and temporal patterns of the fish assemblage of subtropical subestuaries along the Río de la Plata coast (Uruguay)Fish assemblages in subestuaries have been poorly studied worldwide. In order to evaluate the interestuarine and temporal variability of the ichthyofauna of subestuaries along the Uruguayan coast of the Río de la Plata (RdlP), the Pando, Solís Chico and Solís Grande systems were sampled between 2011 and 2013. Fish biomass, abundance, species richness and diversity indices were analysed, defining fish assemblages characterised by a few species and great abundance. Estuarine resident and freshwater species represented 55.5% of the fish assemblage according to estuarine use guilds. Species occurrence was similar in the three subestuaries, but the relative abundances differed among them. The analysed community parameters showed a decreasing trend from west to east along the Uruguayan coast. Highest diversity and fish abundance were recorded in the Pando system located in the proximities of an important spawning area in the inner RdlP estuary. In the Solís Grande subestuary occurred the lowest species richness and fish abundance. The Solís Chico was characterised as a transitional subsystem. All three subestuaries showed an increase in species richness and abundance during high temperature periods, probably related to the life cycle of the species sharing habitats between the RdlP and the coastal subestuaries. This study constitutes the first step in assessing the fish assemblage patterns in coastal ecosystems of the RdlP and an approach about the ecological role of the subestuaries in the southwest Atlantic Ocean. AbstrAct