We expect to develop self-sustaining extraterrestrial colonies, and they will approach being closed ecological systems. Using simple closed ecosystems containing Daphnia magna, three species of algae, and microbes, we tested multiple conditions to study long-term organism survival, which is only possible with adequate nutrient recycling. Closed and open systems behaved differently from one another at high nitrate concentrations; in closed systems, the animals were dead by day 14; in open systems, the Daphnia populations persisted beyond 273 days. Daphnia deaths were associated with increased pH and O caused by greater algal photosynthesis and the lack of exchange with the atmosphere. Replicate variability that used small Daphnia suggested that inadequate grazing capability allowed algae to create conditions unfavorable to Daphnia survival. Over months, algal and Daphnia abundance decreased, presumably because of inadequate nutrient recycling; these populations increased temporarily after the addition of nutrients. The addition of natural lake organisms did not increase the nutrient-recycling capabilities of the systems. Understanding the mechanisms of closed systems will be useful in implementing biological processes in managing life support systems.
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http://dx.doi.org/10.1016/j.lssr.2024.12.002 | DOI Listing |
Naturwissenschaften
January 2025
Institute of Bioengineering and Biosciences, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
While most dentate non-mammalian vertebrates possess simple conical teeth, some demonstrate complex tooth shapes. Lake Malawi cichlid fishes are an extreme example of this, exhibiting a myriad of tooth shapes driven by an ecologically derived rapid evolution of closely related but distinct species. Tooth shape in mammals is generally considered to be established by signaling centers called primary and secondary enamel knots, which are not believed to be present in non-mammalian vertebrates.
View Article and Find Full Text PDFJ Exp Zool A Ecol Integr Physiol
January 2025
Departamento de Biologia, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal.
The open field test (OFT) is frequently used in research to assess anxiety-like behavior and locomotor activity. Its simple design can lead to the misconception that it is a standardized procedure comparable between laboratories. However, some modifications in the setup can cause changes in behavior.
View Article and Find Full Text PDFThe evolutionary transition from simple chordate body plans to complex vertebrate body plans was driven by the acquisition of the neural crest, a stem cell population that retains broad, multi-germ layer developmental potential long after most embryonic cells have become lineage restricted. We have previously shown that neural crest cells share significant gene regulatory architecture with pluripotent blastula stem cells. Here we examine the roles that Krüppel-like Family (Klf) transcription factors play in these stem cell populations.
View Article and Find Full Text PDFAnim Reprod
January 2025
Genetics and Physiology Division, Taiwan Livestock Research Institute, Ministry of Agriculture, Tainan, Taiwan.
Ensuring boar sperm quality before insemination is crucial for maximizing field fertility and efficient pig production. The computer-assisted sperm analysis (CASA) and fluorescence probes combined with flow cytometry (FC) are commonly used techniques for evaluating sperm kinematics and functions, closely related to animal fertility. However, their high cost and complex operations make it challenging to apply them in laboratories or pig breeding farms with limited resources.
View Article and Find Full Text PDFACS Cent Sci
January 2025
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
Photothermal conversion can promote plastic depolymerization (chemical recycling to a monomer) through light-to-heat conversion. The highly localized temperature gradient near the photothermal agent surface allows selective heating with spatial control not observed with bulk pyrolysis. However, identifying and incorporating practical photothermal agents into plastics for end-of-life depolymerization have not been realized.
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