Miniature Ecosystems Research Articles

Investigation of Age Polyethism in Food Processing of the Fungus-Growing Termite Odontotermes formosanus (Blattodea: Termitidae) Using a Laboratory Artificial Rearing System.

Laboratory rearing systems are useful models for studying Rhinotermitid behavior. Information on the biology of fungus-growing termites, however, is limited because of the difficulty of rearing colonies in the laboratory settings. The physical structure of termite nests makes it impossible to photograph or to observe colonies in the field. In this study, an artificial rearing system for field-collected colonies of the fungus-growing termite Odontotermes formosanus (Shiraki) was developed to facilitate observation in the laboratory. We recorded colony activity within the artificial rearing system and documented a variety of social behaviors that occurred throughout the food processing of the colony. This complex miniature ecosystem was cooperatively organized via division of labor in the foraging and processing of plant materials, and the observed patterns largely resembled the caste and age-based principles present in Macrotermes colonies. This work extends our insights into polyethism in the subfamily Macrotermitinae.

Proteomic characterization of the major arthropod associates of the carnivorous pitcher plant Sarracenia purpurea

The array of biomolecules generated by a functioning ecosystem represents both a potential resource for sustainable harvest and a potential indicator of ecosystem health and function. The cupped leaves of the carnivorous pitcher plant, Sarracenia purpurea, harbor a dynamic food web of aquatic invertebrates in a fully functional miniature ecosystem. The energetic base of this food web consists of insect prey, which is shredded by aquatic invertebrates and decomposed by microbes. Biomolecules and metabolites produced by this food web are actively exchanged with the photosynthesizing plant. In this report, we provide the first proteomic characterization of the sacrophagid fly (Fletcherimyia fletcheri), the pitcher plant mosquito (Wyeomyia smithii), and the pitcher-plant midge (Metriocnemus knabi). These three arthropods act as predators, filter feeders, and shredders at distinct trophic levels within the S. purpurea food web. More than 50 proteins from each species were identified, ten of which were predominantly or uniquely found in one species. Furthermore, 19 peptides unique to one of the three species were identified using an assembled database of 100 metazoan myosin heavy chain orthologs. These molecular signatures may be useful in species monitoring within heterogeneous ecosystem biomass and may also serve as indicators of ecosystem state.

Protozoa of biological soil crusts of a cool desert in Utah

In arid and semiarid lands throughout the world, many of the open spaces between higher plants are covered by biological soil crusts, communities of cyanobacteria: algae, lichens, and bryophytes associated with bacteria and fungi. These crusts are miniature ecosystems between the atmosphere and soil, furnishing a habitat where microorganisms conduct nutrient recycles, especially nitrogen fixation, and contribute nutrients to the soils underneath. Photosynthetic components and ecosystem metabolism have been extensively studied, but the microfauna contributing to crust bacterial functioning have received little attention. This study of five crusts in southeastern Utah describes diversity and abundance of the protozoa, which constitute most of the microfauna. Amoebae numbered 680–2500, ciliates 20–460, and testate amoebae 2400–4800 g dry weight of crust material, and increased in numbers in the succession from Microcoleus to lichen to bryophyte crusts. Twenty-eight species of amoebae, 45 of ciliates, and 19 of testate amoebae were found. Acanthamoeba, Hartmanella, Vahlkampfidae, two species of Colpoda, 4–5 other colpodids, a species of Polyhymenophora, and species of the tiny testate genera Cryptodifflugia and Difflugiella furnish most of the protozoa in biological soil crusts communities.

Biomonitoring: The Crucial Link Between Natural Systems and Society

How ironic that, in humankind's quest for sustainability, so little attention is given to the biospheric life support system upon which the human species depends. Since natural systems cannot speak to human society, a continuously operating feedback loop is essential for providing information about a natural system's condition in time to take corrective action when necessary. Investigators must replicate the important cause/effects pathways of natural systems. Biomonitoring is surveillance undertaken to ensure that previously established quality control conditions are being met. Surveillance is the systematic and orderly gathering of data to determine what is happening, but without a prior commitment to initiate remedial action if quality control conditions do not remain within an acceptable range. In order to take remedial action before severe damage has occurred, sampling must be sufficiently frequent and the results quickly available to provide an early warning of deleterious conditions. Micro- and mesocosms are not miniature ecosystems, but rather systems of lesser complexity that provide useful information on selected ecosystem attributes. Their design, study, and extrapolation to larger, multivariate ecosystems require considerable professional judgment. Properly used, micro- and mesocosms provide evidence for decision making that can prevent or diminish damage to larger natural systems for which they act as surrogates.

Rock weathering promoted by embryonic soils in surface cavities

SummaryThe upper surfaces of trachyte outcrops and boulders in Tuscany and Latium have numerous cavities. The cavities have formed from the dislodgement of xenoliths and, if properly oriented, they collect water and accumulate mineral and organic debris. There is no drainage, and water stays in them for a long time, inducing a severe hydrological regimen, but supporting a variety of living organisms such as cyanobacteria, green algae and insects. The humic substances produced by the humification of organic matter and the organic acids released by organisms alter the underlying rock, thereby deepening and enlarging the cavities. Following the dissolution of the glassy cements, crystals detach from the matrix to join the accumulated material, where they are progressively comminuted and partly changed into clay minerals. With time, these accumulations increase in thickness sufficiently to allow the establishment of vascular plants and the development of horizons so as to become embryonic soils. We sampled the material from several such cavities and determined its chemical and mineralogical composition. We conclude that cavities contain miniature ecosystems supported by the tiny bodies of soil in them.

ECA: control in ecosystems.

Although metabolic control analysis (MCA) cannot be applied directly to microbial ecological systems because of mass conservation and stoichiometric constraints, we demonstrate here that Hierarchical Control Analysis (HCA) can be applied to such systems. We illustrate the approach for a particular ecosystem example of the biological synthesis of acetic acid from glucose, and uncover some surprising aspects to the control of this miniature ecosystem.

Purification of industrially contaminated groundwaters using controlled ecosystems

Pollution of ground and surface waters by industrial processes is a widespread and very serious environmental issue. While solutions exist to many of these problems, they frequently remain unused because of high costs often related to the broad spectrum of chemistry involved at individual sites. This paper presents, at bench scale, an amelioration procedure involving miniature ecosystems controlled by algal turf scrubbing (ATS) as applied to contaminated groundwater from a New Jersey (USA) industrial site. The groundwater, with a COD of 1300 mg/l and a TSS of 2000 mg/l, presented a broad array of inorganic elements including magnesium, iron and manganese and minor heavy metals with a suite of twenty synthetic organic compounds. The organic compounds included trichloroethylene, vinyl chloride and acetone, among others, for a concentration averaging 1071 mg/l. On the first experimental run, using metal halide lighting for driving algal photosynthesis, the ATS/microcosm process described herein purified the contaminated water to drinking water standards for all inorganic elements and organic compounds except trichloroethylene and dichloroethylene. Subsequent runs, with low levels of UV-B applied to the ATS, achieved full drinking water standards. An examination of losses due to volatilization showed that minor losses of chlorinated hydrocarbons were also largely avoided with the addition of UV-B. Vinyl chloride was not detected in significant quantities in the volatile suite taken from air over the ATS unit either before or after the supplemental addition of UV-B. ATS is a low-cost ecotechnology that combines metabolic and adsorptive uptake by algae, precipitation at high pH and degradation under a saturated oxygen/UV radiation regime to ameliorate complex industrial wastewaters.