Life cycle assessment on environmental feasibility of microalgae-based wastewater treatment for shrimp recirculating aquaculture systems.

This life cycle assessment (LCA) study analyzed the environmental consequences of integrating microalgae-based wastewater treatment into a shrimp farm with recirculating aquaculture systems (RAS). Microalgae treatment produced <10 % of the system's freshwater eutrophication potential (FEP), marine eutrophication potential (MEP) and global warming potential, which was dominantly contributed by electricity use. Microalgae treatment performed comparably to activated sludge treatment for FEP reduction, and was more effective in remediating marine eutrophication. Replacing coal in electricity mix, particularly with renewables, reduced the system's impacts by up to 90-99 %. Performing the LCA based on system expansion generally obtained higher impacts compared to allocation. Utilizing algal biomass for biogas production reduced the MEP; however, production of feed ingredient and biodiesel were not environmentally beneficial. This study proved the use of microalgae for aquaculture wastewater treatment to be environmentally feasible, the results can guide more sustainable RAS operations and design of full-scale microalgae treatment.

Life cycle assessment on marine aquaponic production of shrimp, red orache, minutina and okahajiki.

Aquaponics is an integrated food production system that intensively produces a diverse array of seafood and specialty crops in one closed-loop system, which is a potential solution to global challenges of food security. While current aquaponics systems are commonly operated with freshwater, marine aquaponics is an emerging opportunity to grow saltwater animals and plants. Although marine aquaponics can reduce the dependence on freshwater for food production, its environmental sustainability has not been systematically studied. This paper presents the first life cycle assessment (LCA) on a marine aquaponic production system growing shrimp and three halophytes. The system assessed covered from shrimp larvae nursery to grow-out. The effects of salinity, carbon/nitrogen (C/N) ratio and shrimp-to-plant stocking density ratio of aquaponics on its midpoint and endpoint environmental impacts were evaluated using a functional unit based on the economic value of the four products. Electricity use for aquaponic operation was the environmental hotspot, contributing ∼90 % to all the midpoint impacts. The system produced higher environmental impacts when operated at higher salinity, but lower C/N ratio and stocking density. Replacing fossil fuel with wind power for electricity generation can decrease the environmental impacts by 95-99 %. Variation in the shrimp price can change the impacts by up to 62 %. This study provides a useful tool to help marine aquaponic farmers improve their production from an environmental perspective, and can serve as groundwork for further assessing more marine aquaponic systems with different animal-plant combinations.

New project? Don't analyze--act.

In a predictable world, getting a new initiative off the ground typically involves analyzing the market, creating a forecast, and writing a business plan. But what about in an unpredictable environment? The authors recommend looking to those who are experts in navigating extreme uncertainty while minimizing risk: serial entrepreneurs. These business leaders act, learn, and build their way into the future. Managers in traditional organizations can do the same, starting with smart, low-risk steps that follow simple rules: Use the means at hand; stay within an acceptable loss; secure only the commitment needed for the next step; bring along only volunteers; link the initiative to a business imperative; produce early results; and manage expectations. Momentum is gained by continuing to act based on what is learned at each step. The launch of Clorox's Green Works product line is discussed as an example.

From innervation density to tactile acuity: 1. Spatial representation.

We tested the hypothesis that the population receptive field representation (a superposition of the excitatory receptive field areas of cells responding to a tactile stimulus) provides spatial information sufficient to mediate one measure of static tactile acuity. In psychophysical tests, two-point discrimination thresholds on the hindlimbs of adult cats varied as a function of stimulus location and orientation, as they do in humans. A statistical model of the excitatory low threshold mechanoreceptive fields of spinocervical, postsynaptic dorsal column and spinothalamic tract neurons was used to simulate the population receptive field representations in this neural population of the one- and two-point stimuli used in the psychophysical experiments. The simulated and observed thresholds were highly correlated. Simulated and observed thresholds' relations to physiological and anatomical variables such as stimulus location and orientation, receptive field size and shape, map scale, and innervation density were strikingly similar. Simulated and observed threshold variations with receptive field size and map scale obeyed simple relationships predicted by the signal detection model, and were statistically indistinguishable from each other. The population receptive field representation therefore contains information sufficient for this discrimination.