Suchergebnisse

Extensive research in geology, atmospheric science, and paleontology provides a detailed history of CO2 in the atmosphere and an understanding of factors that have influenced changes in the past. This knowledge is used to illuminate the role of atmospheric CO2 in the modern carbon cycle and in the evolution of plants and animals. With an understanding of the history and dynamics of the biosphere, the authors address the future role of atmospheric CO2 and its likely effects on ecosystems. This book incorporates the advances of various earth science, environmental, and ecological fields into an overall account of global change and the changing dynamics of life on Earth.

1 Principles of instrumentation for physiological ecology -- 1.1 Introduction -- 1.2 Measurement and measurement errors -- 1.3 Instrument organization -- 1.4 Instrument initiation -- 1.5 Postscript -- 2 Field data acquisition -- 2.1 Introduction -- 2.2 Analog recorders -- 2.3 Digital recorders -- 2.4 Integrators -- 2.5 Sampling considerations -- 3 Water in the environment -- 3.1 Soil moisture -- 3.2 Atmospheric moisture -- 3.3 Moisture flux -- 4 Measurement of wind speed near vegetation -- 4.1 Introduction -- 4.2 Flow in wind tunnels, growth cabinets and ducts -- 4.3 Weather stations and field survey -- 4.4 Wind profiles above vegetation -- 4.5 Boundary layer resistance -- 4.6 Calibration -- 4.7 Aerodynamic influence by masts -- 4.8 Visualization -- 4.9 Pressure measurements -- 4.10 Some applications -- 5 Soil nutrient availability -- 5.1 Introduction -- 5.2 Difficulties in measuring nutrient availability -- 5.3 Nitrogen availability -- 5.4 Phosphorus availability -- 5.5 Sulfur availability -- 5.6 Availability of essential cations -- 5.7 Micronutrient availability -- 5.8 Soil classification -- 5.9 Bioassay of nutrient availability -- 5.10 Soil acidity -- 5.11 Soil salinity -- 5.12 Soil redox potential -- 5.13 Comments on sampling -- 5.14 Index units -- 6 Radiation and light measurements -- 6.1 Introduction -- 6.2 Definitions and units -- 6.3 Energy versus photons as a measure of PAR -- 6.4 Radiation sensors: general characteristics -- 6.5 Determination of the diffuse and direct components of radiation -- 6.6 Calibration of radiation sensors -- 6.7 Sampling considerations -- 6.8 Photographic estimations of light climate -- 6.9 Spectral radiometry -- 7 Temperature and energy budgets -- 7.1 Introduction -- 7.2 Energy budget approach -- 7.3 Variations in air and leaf temperatures with height -- 7.4 Temperature and its measurement -- 7.5 Orientation and its measurement -- 7.6 Calculation of incident solar radiation on different surfaces -- 7.7 Leaf absorptance and its measurement -- 7.8 Boundary layer considerations -- 8 Measurement of transpiration and leaf conductance -- 8.1 Introduction -- 8.2 Leaf transpiration rate -- 8.3 Leaf conductance to water vapor -- 8.4 Instrumentation for transpiration measurements -- 8.5 Calibration of water vapor sensors -- 8.6 Systems for measuring transpiration and leaf conductance -- 8.7 Whole-plant measurements of transpiration -- 9 Plant water status, hydraulic resistance and capacitance -- 9.1 Introduction -- 9.2 Water potential and its components -- 9.3 Water content -- 9.4 Hydraulic resistance and capacitance -- 9.5 Conclusion -- 10 Approaches to studying nutrient uptake, use and loss in plants -- 10.1 Introduction -- 10.2 Nutrient uptake -- 10.3 Nutrient use and nutrient status -- 10.4 Chemical analysis -- 10.5 Nutrient loss -- 11 Photosynthesis: principles and field techniques -- 11.1 The system concept -- 11.2 Principles of photosynthesis measurement -- 11.3 Components of gas-exchange systems -- 11.4 Real photosynthesis systems -- 11.5 Matching instrument to objective -- 11.6 Calibrating photosynthesis systems -- 11.7 Calculating gas-exchange parameters -- 11.8 List of symbols -- 12 Crassulacean acid metabolism -- 12.1 Introduction -- 12.2 Measurement of succulence -- 12.3 Nocturnal acidification -- 12.4 Nocturnal CO2 fixation -- 12.5 Analysis of day-night and seasonal patterns of CO2 and H2O vapor exchange -- 12.6 Measurement of photosynthesis and respiration by O2 exchange -- 12.7 Water relations -- 12.8 Stress physiology -- 13 Stable isotopes -- 13.1 Introduction -- 13.2 Natural abundances of stable isotopes of ecological interest -- 13.3 Stable isotope mass spectrometry -- 13.4 Sample preparation -- 13.5 Sample variability -- 13.6 Application of stable isotopes in ecological studies -- 14 Canopy structure -- 14.1 Introduction -- 14.2 Direct methods -- 14.3 Semidirect methods -- 14.4 Indirect methods -- 14.5 Summary -- 15 Growth, carbon allocation and cost of plant tissues -- 15.1 Introduction -- 15.2 Growth analysis -- 15.3 Fate of carbon -- 15.4 Carbon and energy costs of growth and maintenance -- 16 Root systems -- 16.1 Introduction -- 16.2 Assessing root system structure and biomass in the field — determining what is there -- 16.3 Determination of root length and surface area -- 16.4 Microscale distributions of roots -- 16.5 Root system turnover and production -- 16.6 Root phenology and growth -- 16.7 Root system function -- 16.8 Root associations -- 16.9 Concluding thoughts -- 17 Field methods used for air pollution research with plants -- 17.1 Introduction -- 17.2 Studies of air pollution absorption -- 17.3 Air pollution instrumentation -- 17.4 Cuvettes -- 17.5 Field fumigation systems and approaches -- 17.6 Summary.

In natural grasslands, C-4 plant dominance increases with growing season temperatures and reflects distinct differences in plant growth rates and water use efficiencies of C-3 vs. C-4 photosynthetic pathways. However, in lawns, management decisions influence interactions between planted turfgrass and weed species, leading to some uncertainty about the degree of human vs. climatic controls on lawn species distributions. We measured herbaceous plant carbon isotope ratios (delta C-13, index of C-3/C-4 relative abundance) and C-4 cover in residential lawns across seven U.S. cities to determine how climate, lawn plant management, or interactions between climate and plant management influenced C-4 lawn cover. We also calculated theoretical C-4 carbon gain predicted by a plant physiological model as an index of expected C-4 cover due to growing season climatic conditions in each city. Contrary to theoretical predictions, plant delta C-13 and C-4 cover in urban lawns were more strongly related to mean annual temperature than to growing season temperature. Wintertime temperatures influenced the distribution of C-4 lawn turf plants, contrary to natural ecosystems where growing season temperatures primarily drive C-4 distributions. C-4 cover in lawns was greatest in the three warmest cities, due to an interaction between climate and homeowner plant management (e.g., planting C-4 turf species) in these cities. The proportion of C-4 lawn species was similar to the proportion of C-4 species in the regional grass flora. However, the majority of C-4 species were nonnative turf grasses, and not of regional origin. While temperature was a strong control on lawn species composition across the United States, cities differed as to whether these patterns were driven by cultivated lawn grasses vs. weedy species. In some cities, biotic interactions with weedy plants appeared to dominate, while in other cities, C-4 plants were predominantly imported and cultivated. Elevated CO2 and temperature in cities can influence C-3/C-4 competitive outcomes; however, this study provides evidence that climate and plant management dynamics influence biogeography and ecology of C-3/C-4 plants in lawns. Their differing water and nutrient use efficiency may have substantial impacts on carbon, water, energy, and nutrient budgets across cities. ; U.S. National Science Foundation Macrosystems Biology Program [EF-1065548, 1065737, 1065740, 1065741, 1065772, 1065785, 1065831, 121238320] ; This research was funded by a series of collaborative grants from the U.S. National Science Foundation Macrosystems Biology Program (EF-1065548, 1065737, 1065740, 1065741, 1065772, 1065785, 1065831, 121238320). The authors thank La'Shaye Ervin, William Borrowman, Moumita Kundu, and Barbara Uhl for field and laboratory assistance. ; Public domain authored by a U.S. government employee