Changes of the isotopic composition of water within the water cycle provide a recognizable signature, relating such water to the different phases of the cycle. The isotope fractionations that accompany the evaporation from the ocean and other surface waters and the reverse process of rain formation account for the most notable changes. As a result, meteoric waters are depleted in the heavy isotopic species of H and O relative to ocean waters, whereas waters in evaporative systems such as lakes, plants, and soilwaters are relatively enriched. During the passage through the aquifers, the isotope composition of water is essentially a conservative property at ambient temperatures, but at elevated temperatures, interaction with the rock matrix may perturb the isotope composition. These changes of the isotope composition in atmospheric waters, surface water, soil, and groundwaters, as well as in the biosphere, are applied in the characterization of hydrological system as well as indicators of paleo-climatological conditions in proxy materials in climatic archives, such as ice, lake sediments, or organic materials.

Oxygen and hydrogen isotopes in the hydrologic cycle

https://www.uni-frankfurt.de/45217760/lehner_doell_JHydrol2004_GLWD.pdf

Development and validation of a global database of lakes, reservoirs and wetlands

Communities of microscopic plant life, or phytoplankton, dominate the Earth's aquatic ecosystems. This important new book by Colin Reynolds covers the adaptations, physiology and population dynamics of phytoplankton communities in lakes and rivers and oceans. It provides basic information on composition, morphology and physiology of the main phyletic groups represented in marine and freshwater systems and in addition reviews recent advances in community ecology, developing an appreciation of assembly processes, co-existence and competition, disturbance and diversity. Although focussed on one group of organisms, the book develops many concepts relevant to ecology in the broadest sense, and as such will appeal to graduate students and researchers in ecology, limnology and oceanography.

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The Ecology of Phytoplankton

▪ Abstract The use of stable isotope techniques in plant ecological research has grown steadily during the past two decades. This trend will continue as investigators realize that stable isotopes can serve as valuable nonradioactive tracers and nondestructive integrators of how plants today and in the past have interacted with and responded to their abiotic and biotic environments. At the center of nearly all plant ecological research which has made use of stable isotope methods are the notions of interactions and the resources that mediate or influence them. Our review, therefore, highlights recent advances in plant ecology that have embraced these notions, particularly at different spatial and temporal scales. Specifically, we review how isotope measurements associated with the critical plant resources carbon, water, and nitrogen have helped deepen our understanding of plant-resource acquisition, plant interactions with other organisms, and the role of plants in ecosystem studies. Where possible we also...

Stable Isotopes in Plant Ecology

Carbon dioxide (CO2) transfer from inland waters to the atmosphere, known as CO2 evasion, is a component of the global carbon cycle. Global estimates of CO2 evasion have been hampered, however, by the lack of a framework for estimating the inland water surface area and gas transfer velocity and by the absence of a global CO2 database. Here we report regional variations in global inland water surface area, dissolved CO2 and gas transfer velocity. We obtain global CO2 evasion rates of 1.8(-0.25)(+0.25) petagrams of carbon (Pg C) per year from streams and rivers and 0.32(-0.26)(+0.52) Pg C yr(-1) from lakes and reservoirs, where the upper and lower limits are respectively the 5th and 95th confidence interval percentiles. The resulting global evasion rate of 2.1 Pg C yr(-1) is higher than previous estimates owing to a larger stream and river evasion rate. Our analysis predicts global hotspots in stream and river evasion, with about 70 per cent of the flux occurring over just 20 per cent of the land surface. The source of inland water CO2 is still not known with certainty and new studies are needed to research the mechanisms controlling CO2 evasion globally.

/pdf/global-carbon-dioxide-emissions-from-inland-waters-37ag7u7xbc.pdf

Global carbon dioxide emissions from inland waters

Stable isotope hydrology : deuterium and oxygen-18 in the water cycle

A lake, as a body of water, is in continuous interaction with the rocks and soils in its drainage basin, the atmosphere, and surface and groundwaters. Human industrial and agricultural activities introduce new inputs and processes into lake systems. This volume presents a selection of 10 contributions dealing with diverse aspects of lake systems, including such subjects as the geological controls of lake basins and their histories, mixing and circulation patterns in lakes, gaseous exchange between the water and atmosphere, and human input to lakes through atmospheric precipitation and surfical runoff. This work was written with a dual goal in mind: to serve as a textbook and to provide professionals with in-depth expositions and discussions of the more important aspects os lake systems.

Physics and Chemistry of Lakes

Activities and concentrations of oxygen-18 in concentrated aqueous salt solutions: Analytical and geophysical implications

The enrichment of the heavy isotopic species (H2 18O and HDO) in surface waters and lakes was already observed during the early surveys of stable isotope variations in the hydrological cycle (Rankama 1954). Craig (1961a) noted that the isotope compositions of waters from African lakes were displaced in δ-D vs δ-18O space relative to other freshwaters whose composition follows the meteoric water line (MWL).

Joel R Gat

Papers

Oxygen and hydrogen isotopes in the hydrologic cycle

Stable isotope hydrology : deuterium and oxygen-18 in the water cycle

Physics and Chemistry of Lakes

Activities and concentrations of oxygen-18 in concentrated aqueous salt solutions: Analytical and geophysical implications

Stable Isotopes of Fresh and Saline Lakes