Development of High‐Level Omega‐3 Eicosapentaenoic Acid (EPA) Production from Phaeodactylum tricornutum

Phaeodactylum tricornutum is a lipid‐rich marine diatom that contains a high level of omega‐3 polyunsaturated fatty acids, especially eicosapentaenoic acid (EPA). In an effort to reduce costs for large‐scale cultivation of this microalga, this study first established a New BBM medium (0.3 x strength BBM with only 3% of the initial phosphate level) to replace the traditional F/2 medium. Phaeodactylum tricornutum could grow in extremely low phosphate concentrations (25 µM), without compromising the EPA content. In the presence of sea salts, silicate addition was not necessary for high rate growth, high EPA content, or lipid accumulation in this species. Using urea as the sole nitrogen source tended to increase EPA contents per dry biomass (by 24.7%) while not affecting growth performance. The use of sea salts, rather than just sodium chloride, led to significantly improved biomass yields (20% increase) and EPA contents of total fatty acid (46–52% increase), most likely because it supplied sufficient essential elements such as magnesium. A salinity level of 35 led to significantly higher biomass yields compared with 20, but salinity had no significant influence on EPA content. EPA became the dominant fatty acid with average levels of 51.8% of total fatty acids during the exponential growth phase at 20 ppt in New BBM medium with sea salts.     

Dogs Detect Larger Wind Energy Effects on Bats and Birds

As wind turbine-caused mortality of birds and bats increases with increasing wind energy capacity, accurate fatality estimates are needed to assess effects, identify collision factors, and formulate mitigation. Finding a larger proportion of collision victims reduces the magnitude of adjustment for the proportion not found, thus reducing opportunities for bias. We tested detection dogs in trials of bat and small-bird carcasses placed randomly in routine fatality monitoring at the Buena Vista and Golden Hills Wind Energy projects, California, USA, 2017. Of trial carcasses placed and confirmed available before next-day fatality searches, dogs detected 96% of bats and 90% of small birds, whereas humans at a neighboring wind project detected 6% of bats and 30% of small birds. At Golden Hills dogs found 71 bat fatalities in 55 searches compared to 1 bat found by humans in 69 searches within the same search plots over the same season. Dog detection rates of trial carcasses remained unchanged with distance from turbine, and dogs found more fatalities than did humans at greater distances from turbines. Patterns of fatalities found by dogs within search plots indicated 20% of birds and 4–14% of bats remained undetected outside search plots at Buena Vista and Golden Hills. Dogs also increased estimates of carcass persistence by finding detection trial carcasses that the trial administrator had erroneously concluded were removed. Compared to human searches, dog searches resulted in fatality estimates up to 6.4 and 2.7 times higher for bats and small birds, respectively, along with higher relative precision and >90% lower cost per fatality detection. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.     

Frog breeding in rain-fed wetlands after a period of severe drought: implications for predicting the impacts of climate change

Globally, rain-fed wetlands provide critical habitat for a wide range of amphibian species, however, information on the use of rain-fed wetlands by Australian frog species is extremely limited. This study examined the distribution of frog breeding in rain-fed wetlands following the first significant rain event after a period of severe drought (2002–2009) in order to predict how frog communities may be affected in the future by changed climate. Tadpole communities along with vegetation and water quality variables were described in 35 rain-fed wetlands across the South West Slopes and Riverina bioregions of inland south-eastern Australia. In addition, weekly tadpole surveys were conducted in a subset of these wetlands to describe temporal patterns of occupancy. Despite the protracted dry period prior to this study 50% of the rain-fed wetlands surveyed contained tadpoles. However, frog communities were species poor with only five species recorded. The majority of wetlands were dominated be a single species, Limnodynastes tasmaniensis which is also common within permanent waterbodies such as farm dams and irrigation infrastructure in both bioregions. Tadpoles of two burrowing species L. interioris and Neobatrachus sudelli were restricted to a small number of wetlands mostly in the South West Slopes. The composition of tadpole communities changed over time, and Crinia parinsignifera was the only species that continued to breed over winter. The dominance of generalist species within rain-fed wetlands indicates that characteristics such as dispersal capability, flexibility in breeding times and the ability to utilise created habitats may be more important than burrowing ability and longevity when predicting vulnerability to climate change.     

Engineering photosynthetic light capture: impacts on improved solar energy to biomass conversion

The main function of the photosynthetic process is to capture solar energy and to store it in the form of chemical 'fuels'. Increasingly, the photosynthetic machinery is being used for the production of biofuels such as bio-ethanol, biodiesel and bio-H₂. Fuel production efficiency is directly dependent on the solar photon capture and conversion efficiency of the system. Green algae (e.g. Chlamydomonas reinhardtii ) have evolved genetic strategies to assemble large light-harvesting antenna complexes (LHC) to maximize light capture under low-light conditions, with the downside that under high solar irradiance, most of the absorbed photons are wasted as fluorescence and heat to protect against photodamage. This limits the production process efficiency of mass culture. We applied RNAi technology to down-regulate the entire LHC gene family simultaneously to reduce energy losses by fluorescence and heat. The mutant Stm3LR3 had significantly reduced levels of LHCI and LHCII mRNAs and proteins while chlorophyll and pigment synthesis was functional. The grana were markedly less tightly stacked, consistent with the role of LHCII. Stm3LR3 also exhibited reduced levels of fluorescence, a higher photosynthetic quantum yield and a reduced sensitivity to photoinhibition, resulting in an increased efficiency of cell cultivation under elevated light conditions. Collectively, these properties offer three advantages in terms of algal bioreactor efficiency under natural high-light levels: (i) reduced fluorescence and LHC-dependent heat losses and thus increased photosynthetic efficiencies under high-light conditions; (ii) improved light penetration properties; and (iii) potentially reduced risk of oxidative photodamage of PSII.     

Energy‐Dense Snack Food Intake in Adolescence: Longitudinal Relationship to Weight and Fatness

Objective: The longitudinal relationship between the consumption of energy‐dense snack (EDS) foods and relative weight change during adolescence is uncertain. Using data from the Massachusetts Institute of Technology Growth and Development Study, the current analysis was undertaken to examine the longitudinal relationship of EDS food intake with relative weight status and percentage body fat and to examine how EDS food consumption is related to television viewing. Research Methods and Procedures: One hundred ninety‐six nonobese premenarcheal girls 8 to 12 years old were enrolled between 1990 and 1993 and followed until 4 years after menarche. At each annual follow‐up visit, data were collected on percentage body fat (%BF), BMI z score, and dietary intake. Categories of EDS foods considered were baked goods, ice cream, chips, sugar‐sweetened soda, and candy. Results: At study entry, girls had a mean ± SD BMI z score of ?0.27 ± 0.89, consumed 2.3 ± 1.7 servings of EDS foods per day, and consumed 15.7 ± 8.1% of daily calories from EDS foods. Linear mixed effects modeling indicated no relationship between BMI z score or %BF and total EDS food consumption. Soda was the only EDS food that was significantly related to BMI z score over the 10‐year study period, but it was not related to %BF. In addition, a significant, positive relationship was observed between EDS food consumption and television viewing. Discussion: In this cohort of initially nonobese girls, overall EDS food consumption does not seem to influence weight status or fatness change over the adolescent period.