For future, the filtering screen of tanks should be of a finer mesh so as to allow longer retention of Artemia. This may require more frequent tank cleaning, perhaps stressing larvae, but the trade off would be observation of true feeding rates, which is required for maximizing efficiency of feeding schedules and densities. Possible cannibalism was observed occasionally, potentially indicating insufficient feed levels. Victims were usually white or translucent in color, which made it hard to distinguish between a mortality or exuviate. Since many crustaceans ingest their exuviae, it is possible this was natural feeding behavior ; it is also possible that larvae were cannibalizing each other due to lack of satiety. The uncertainty of this observation and that this occurred in the presence and absence of food renders this inconclusive. As Kelly and Price & Chew both observed that most mortalities occurred in ecdysis, it is likely that failure during the molting process caused mortality. In regards to investigating aquaculture potential, future research should include large scaler trials of laboratory rearing with a priority on higher stocking densities and food conversion ratios.The developmental period observed here is within the faster end of the range defined in previous studies and it would be useful to know if warmer temperatures could speed up the process further without significant increase in mortality. This trial experienced a maximum temperature of 19.4ᵒC, with sustained 19ᵒC temperatures for up to seven hours. Though not quite at the 21ᵒC thermal maximum,drying rack cannabis this culturing environment was very different than their natural habitat.
Local waters did not reach higher temperatures until about halfway through the trial, so it would be interesting to see what impact consistently elevated temperature has during earlier larval stages. Furthermore, limitations in tank design prevented observations of feeding rates or food conversion ratios. Another essential question for aquaculture is the source of new stock. It is unknown if female spot prawns spawn more than twice in a lifetime, which would result a high turnover of brood stock. Until farmed specimens reached female maturity at four to five years, brood stock would have to be supplied from the wild. It is prudent to learn more about the reproductive capacity of mature spot prawns in order to provide a consistent supply of hardy larvae. Can females spawn for more than two years? Can fecundity be increased or stabilized by environmental conditions or does it continue to decrease each consecutive spawning? Do specimens from San Diego have the same seven- to eight-year lifespan estimated in Alaskan prawns ? Will they spawn in captivity? These questions are critical in establishing any level of commercial production and would also provide valuable information for future management of the wild fishery.Finally, Litopenaeus vannamei is currently the marine species shrimp with the greatest global production by mass . This results in a wealth of knowledge in regards to techniques for disease prevention, brood stock maintenance, and other marine species obstacles that will likely be applicable to spot prawns. Some of the procedures for the current study were directed by methods used with L. vannamei. Macrobrachium rosenbergii, known as giant river prawns, are a freshwater shrimp that is also farmed. Farming methods for freshwater species are very different, though of all shrimp species farmed at a commercial-scale, M. rosenbergii is genetically of closest relation to spot prawns. M. rosenbergii and P. platyceros are both of the infraorder Caridae, so this freshwater species may provide a stronger biological reference for production timelines and practices . It would be prudent to use both species in directing future research regarding P. platyceros.
Microorganisms are fundamentally important to the functioning of ecosystems, including that of the human body itself. The built environment is an ecosystem of great interest because people in the developed world spend nearly 90% of their lives in buildings. Studying the role of the built environment in exposing humans to specific microbes and the role of microbes responsible for the deterioration of building materials has a rich history. Recently, partly spurred by a research initiative sponsored by the Alfred P. Sloan Foundation, research efforts have expanded to include the “micro-biomes” of indoor environments and the processes that shape these micro-biomes. Here, we use the term micro-biome to refer to the collection of microorganisms inhabiting a particular environment and, in this case, those found in structures built primarily for human occupancy. Research interest in the microbiology of built environments is high , and the research area is increasingly emphasized within basic microbiology and indoor air quality scientific societies. In order to summarize ongoing research e specifically focusing on efforts that rely on DNA-based research methods e and to propose future endeavors, we present ten questions and answers regarding our understanding of the built environment micro-biome.The micro-biome of indoor environments comprise a large number of different taxonomic groups. For example, a survey of homes across the United States revealed on average approximately 7000 different types based on sequence similarity of bacteria and 2000 types of fungi per house in the dust on the upper trim of an inside door. Another study of a neonatal intensive care unit in a hospital identified an average of approximately 12,000 bacterial OTUs on various surfaces per room. Common bacterial genera in indoor environments include Staphylococcus, Corynebacterium, Lactococcus, Firmicutes, and Actinobacteria, while common fungi are Cladosporium, Penicillium, and Aspergillus.
While there are a variety of microorganisms in indoor environments, methodological hurdles have largely limited work to bacteria and fungi. For instance, studies considering viruses have typically targeted specific viruses in particular indoor settings, such as daycares. As such, a comprehensive understanding of the community of viruses and their effects on other microbes, as well potential implications for human health, is still lacking. Similarly, little data exists on the activity and viability of microorganisms identified by DNA sequencing methods. Previous investigations in cleanrooms have suggested that as little as 1e10% of identified sequences and 1% of the overall microbial concentration corresponds to microbes with intact membranes. The multitude of recent studies examining various indoor micro-biomes reveals that microbial communities in indoor environments are complex and highly variable. To help interpret the different studies, we propose a mechanistic framework that unites a material-balance approach of engineering with the ecological concept of meta communities, which both seek to track the sources and snks of a constituent in a system . A material-balance approach draws on the principle of conservation of mass to track the material entering and leaving a system, while in ecological theory, meta communities are considered sets of local communities linked by the dispersal of organisms. Along with environmental heterogeneity, there are demographic parameters that structure meta communities, and these demographic parameters have direct analogs in the material-balance approach. Adopting the mass-balance framework of aerosols, inputs to the system arrive from ventilation, infiltration, and indoor emissions, while removal comes about through deposition, exfiltration, and ventilation . Analogously, within a biological system inputs to the system come as immigrants or originate in the system through births, and loss from the system results from emigration . When linking the abiotic and inactive nature of particles typically considered in aerosol models with active biological organisms that appear in aerosol form , additional considerations need to be made. For instance, the pool of microbes could self-propagate and expand in population size, should favorable growth conditions exist; likewise, the death of an organism within the environment is not necessarily a loss to the system, because dead organisms can persist in the indoor environment and be resuspended as an aerosol. Similarly, not all microbes should be considered as pollutants or contaminants that warrant efforts to limit exposure in the indoor environment. We propose this integrated framework,growers solution greenhouse which combine principles of particle transport and microbial demographics, to inform how micro-biomes of indoor environments assemble to generate indoor micro-biome patterns observed across a variety of settings. Understanding the source strengths of the different processes aids interpretation and generalization of findings from vastly different indoor environments, from transit systems to homes to hospitals and the International Space Station, and across geographic areas where the outdoor environment and building design, operation, and use vary.
For example, different rates and types of bio-aerosol immigration comes about through different forms of ventilation, and different surfaces are expected to have different rates of microbial immigration through the nature and extent of human contact. Similarly, the likelihood of propagation will likely depend on the water and nutrient context where the microorganism is deposited, with important implications for the source pool for indoor emissions. As such, growth in indoor environments likely does not contribute greatly to indoor microbial communities, except on surfaces with intentional and unintentional water use. Microbial quantity can also be incorporated into this framework, as has been done showing that human occupancy contributes ~14 to ~37 million bacterial genome copies per person per hour to air. This could similarly be done with temporal dynamics, as the strength of different immigration rates are known to vary with outdoor and building conditions.The abundance, composition, and diversity of microbial communities found in buildings are the products of dynamic interactions between outdoor air, the building itself , and occupants. Using the framework developed in Q1 , we discuss how building location, operation, and design human occupants and their activities, and indoor environmental conditions each contribute to structuring the micro-biomes of buildings. We should note that while this review focuses primarily on findings from recent studies using DNA-based methods, some of the same conclusions have also been drawn from decades of applying culture based methods to study indoor microbes.The microbes in outdoor air are geographically patterned, and this structure transfers to indoor environments. Spatial variation in the outdoors likely results from differences in land use and vegetation type which in turn host different microbial communities that get entrained in the passing air, and temporal variation in sources can result from varying seasonal and climatic variables. Building operation e specifically, the ventilation strategy used e has been shown to influence the inputs of microbial communities from these outdoor sources through ventilation and infiltration, or immigrants to the system. The source strength of outdoor air varies by ventilation type: within mechanically or naturally ventilated buildings, the magnitude and source of the ventilation air delivery rate affects the relative contribution of outdoor air, such that rooms with natural ventilation or modest supply air filtration show microbial profiles that are similar to outdoor air and a weaker influence from other sources. Accordingly, Ruiz-Calderon et al.recently showed that houses along an intensifying urbanization gradient showed a decrease in outdoor associated bacteria, such as Intrasporangiaceae and Rhodobacteraceae, and an increase of human-associated bacteria, for example Streptococcaceae, Lactobacillaceae, and Pseudomonadaceae. In addition, architectural and interior building design have been shown to influence the types of bacteria that accumulate indoors, in part because variations in building form and interior spatial arrangements can alter the way occupants utilize the built spaces and impact the magnitude and directionality of human-mediated microbial transport indoors.Humans are an important source of microbial inputs into built environments, typically accounting for between 5% and 40% of sequence reads . Humans contribute to the indoor micro-biome via two major routes. First, the micro-biome of occupants, including people and pets, has been identified in air and on surfaces in the indoor environment. Higher levels of occupancy and activity will influence the abundance and composition of bacteria found indoors because we shed a large quantity of micro-beladen particles from our bodies. The rate of direct and indirect contact between people and surfaces will also influence the structure and diversity of bacterial communities found on surfaces. The second route by which occupants generate particles indoors is through their movements, which causes resuspension of settled particles even if they are not the original source of those microbes. For example, Yamamoto et al. showed that occupant-generated emissions contributed approximately 80% of the allergenic fungi in the aerosols of university classrooms, thus contributing more substantially then outdoor contributions from ventilation. The type of activity and flooring can also influence resuspension amounts, demonstrating an interaction between human occupancy and specific building parameters.Indoor surfaces create unique ecosystems in the indoor environment.