Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

Statistics for Spatial Data.

The use of stable isotopes to solve biogeochemical problems in ecosystem analysis is increasing rapidly because stable isotope data can contribute both source-sink (tracer) and process information: The elements C, N, S, H, and all have more than one isotope, and isotopic compositions of natural materials can be measured with great precision with a mass spectrometer. Isotopic compositions change in predictable ways as elements cycle through the biosphere. These changes have been exploited by geochemists to understand the global elemental cycles. Ecologists have not until quite recently employed these techniques. The reasons for this are, first, that most ecologists do not have the background in chemistry and geochemistry to be fully aware of the possibilities for exploiting the natural variations in stable isotopic compositions, and second, that stable isotope ratio measurements require equipment not normally available to ecologists. This is unfortunate because some of the more intractable problems in ecology can be profitably addressed using stable isotope measurements. Stable isotopes are ideally suited to increase our understanding of element cycles in ecosystems. This review is written for ecologists who would like to learn more about how stable isotope analyses have been and can be used in ecosystem studies. We begin with an explanation of isotope terminology and fractionation, then summarize isotopic distributions in the C, N, and S biogeochemical cycles, and conclude with five case studies that show how stable isotope measurements can provide crucial information for ecosystem analysis. We restrict this review to studies of natural variations in C, N, and S isotopic abundances, cxcluding from consideration ~5N enrichment studies and hydrogen and oxygen isotope studies. Our focus on C, N, and S derives in part from our

Stable isotopes in ecosystem studies

Aquatic chemistry is becoming both a rewarding and substantial area of inquiry and is drawing many prominent scientists to its fold. Its literature has changed from a compilation of compositional tables to studies of the chemical reactions occurring within the aquatic environments. But more than this is the recognition that human society in part is determining the nature of aquatic systems. Since rivers deliver to the world ocean most of its dissolved and particulate components, the interactions of these two sets of waters determine the vitality of our coastal waters. This significant vol ume provides not only an introduction to the dynamics of aquatic chem istries but also identifies those materials that jeopardize the resources of both the marine and fluvial domains. Its very title provides its emphasis but clearly not its breadth in considering natural processes. The book will be of great value to those environmental scientists who are dedicated to keeping the resources of the hydrosphere renewable. As the size of the world population becomes larger in the near future and as the uses of materials and energy show parallel increases, the rivers and oceans must be considered as a resource to accept some of the wastes of society. The ability of these waters and the sediments below them to accommodate wastes must be assessed continually. The key questions relate to the capacities of aqueous systems to carry one or more pollutants."

Metal pollution in the aquatic environment

We review the biogeography of microorganisms in light of the biogeography of macroorganisms A large body of research supports the idea that free-living microbial taxa exhibit biogeographic patterns Current evidence confirms that, as proposed by the Baas-Becking hypothesis, 'the environment selects' and is, in part, responsible for spatial variation in microbial diversity However, recent studies also dispute the idea that 'everything is everywhere' We also consider how the processes that generate and maintain biogeographic patterns in macroorganisms could operate in the microbial world

/pdf/microbial-biogeography-putting-microorganisms-on-the-map-1k7e5do5pn.pdf

Microbial biogeography : putting microorganisms on the map

Dynamac CorporationABSTRACTThe inclusion of bioregenerative life support elements (i.e.,plant growth systems and bioreactors) will significantlyincrease the total abundance of microorganisms inextraterrestrial facilities. If the microbial communitiesassociated with these systems (e.g., biofilms attached to plantroots or hardware surfaces) serve as reservoirs for potentiallypathogenic human-associated bacteria, then bioregenerativesystems may represent a human health risk. Research at theKennedy Space Center during the past several years hasattempted to quantify this risk by assessing the capacity ofdifferent human-associated bacteria to survive in prototypeALS systems. Preliminary, short-term studies indicated thatmany potentially pathogenic human-associated bacterialspecies identified from past space missions ( Pseudomonasaeruginosa , Pseudomonas cepacia , Escherichia coli ,Staphylococcus aureus , and Streptococcus pyogenes ) have thecapacity to grow on the roots of plants, one of the largestpotential sites of microbial activity in bioregenerative lifesupport systems. However, only P. aeruginosa could persist atdetectable levels when competition from typical root-associated bacteria was present. Subsequent long-term plantgrowth experiments have confirmed the greater capacity of P.aeruginosa to persist in plant growth systems, although nohuman-associated bacteria tested to date have proliferated inthe systems. Rather, relative success is measured by the rate atwhich bacterial numbers decrease following introduction.Recent and current studies have focused on the influence ofcommunity richness (i.e., the number of microbial species) onthe ability of introduced human-associated bacteria to persistwithin prototype systems. Richness may be manipulated in abioregenerative system; a stringent decontamination approachcould lead to very low richness, but specific inoculation witheither defined bacterial isolates or undefined mixtures ofmicrobial communities would increase richness.INTRODUCTIONAlthough microbes are capable of growing anywhereeven a small amount of liquid water exists, habitats thatcontain organic carbon that can be used as an energy source bythe microorganisms will support abundant microbialpopulations. The inclusion of bioregenerative life support(BLS) elements (i.e., plant growth systems and bioreactors forwaste processing) will significantly increase the totalabundance of microbes in extraterrestrial facilities. Forexample, bacterial numbers on the roots of plants withinprototype hydroponic systems can be as high as 10

Survival of Human-Associated Bacteria in Prototype Advanced Life Support Systems

Strategies for the inoculation of bioreactors for long-term space missions include communities of diverse composition or, alternatively, communities of a few organisms selected for their ability to efficiently catalyze reactions of interest in the reactor. The concept of functional redundancy states that in a diverse community, several different organisms may be present that are capable of effecting processes necessary to the maintenance of the system function. The concept implies that if some members of the community are lost, others will be able to keep the system from failing in the critical reactions that take place therein. In a sewage reactor in the laboratory, a diverse community at steady state was perturbed by elimination of aeration for seven days. Chemical pools (NH4, NO3, dissolved O2), pH, and CO2 evolution were monitored before, during, and after the perturbation. CO2 evolution remained relatively stable, throughout the one-month incubation, although there were strong deviations at the time when the oxygen was initially excluded, and again when O2 was reintroduced. During the anoxic period, NO3 disappeared, and ammonia increased substantially, along with the pH. When the aeration was resumed, reactor conditions approached those of the predisturbance period. The microbial community, analyzed by TRFLP fingerprinting, changed substantially during the anaerobic period, and changed again when aeration was resumed; however, the final community was not similar in composition to the initial community, even though the functional ability of the post-disturbance community became similar to that of the initial assemblage. We conclude that redundancy of function within the community members accounted for the similarity of function under similar environmental conditions, although the community composition did not recover its original form. INTRODUCTION The use of bioreactor systems in human habitats in space or in planetary colonies begs the question of stability of function over long time periods during which structural changes in the resident community are likely to occur. One approach for establishing such reactors includes the use of only selected strains of microbes in the reactors. While this approach maximizes control of the organisms in the system in which the crew exists, alteration of a single population or loss of a population from the reactor could mean failure of the system to function in the way it was intended. Such an event could jeopardize the success of the mission and put the crew at substantial risk. An alternative to the gnotobiotic approach is to use natural communities that have been acclimated for bioreactor purposes. Natural communities of microbes comprise substantially more types than communities of higher organisms; the term hyperdiverse has been applied to these communities to indicate the tremendous variety of types of organisms existing together as a community. Hyperdiverse microbial communities exhibit substantial congeneric homotaxis, which imparts to them high functional redundancy, or degeneracy. For common functions such as metabolism of glucose, acetate, citrate, etc., even extreme dilution, which eliminates most of the types from the community, does not remove the function from the community (Franklin and Mills, 2003b). Furthermore, if the biomass is made similar among the dilution treatments, the rates of the catabolic reactions (determined by C uptake) are not significantly different. These results suggest that degeneracy in hyperdiverse communities provides a level of functional stability to the system in which the community resides. DAY 0 5 10 15 20 25 30 m g C O 2 0 200 400 600 80

Functional Redundancy Promotes Functional Stability in Diverse Microbial Bioreactor Communities

Most sulphur diagenesis models predict that SO42- concentrations decrease exponentially with increasing sediment depth and are lower than that of the overlying water throughout the sediments. Low SO42- concentrations (less than 0.2 mM) are common in the sediments of Lake Anna that receive acid mine drainage; however, sediment with as much as 20 mM SO42- at about 20cm below the sediment surface is also seen in this section of the lake. A decision tree was proposed to investigate the cause of the high SO42- concentrations at depth (HSD) in the sediment. The first possibility proposed was that an increase in the quantity of groundwater flowing through Lake Anna sediments may increase groundwater advection of SO42- or oxygen which would induce sulphide oxidation. This hypothesis was tested by measuring groundwater flow. HSD profiles were found in a discrete region of the lake; however, stations having these profiles did not have higher groundwater flow than other sites sampled. Alternate explanations for the HSD profiles were that the region in which they occurred had: (1) unusual sediment chemical compositions; (2) a different source of regional groundwater, or (3) a lateral intrusion of high SO42- groundwater. There were no differences in sulphide and organic matter concentrations between the two regions. The area which has HSD in the sediment covers a large area in the middle of the lake, so it is unlikely that it has a unique source of regional groundwater. The third alternative was supported by the fact that in all three sample years, HSD stations were located in the preimpoundment stream channel, which is a likely lateral flow path for groundwater containing high SO42- concentrations.

Interactions between groundwater seepage and sediment porewater sulphate concentration profiles in lake anna, Virginia

Early diagenesis of sulfur in the sediments of lakes that receive acid mine drainage

Introduction to environmental technology

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