Aquatic ecosystems
[...]... of North Carolina, Chapel Hill, North Carolina 27599 This Page Intentionally Left Blank Preface Dissolved organic matter (DOM) is the major form of organic matter in almost all aquatic ecosystems It plays significant roles in aquatic food webs, mediates the availability of dissolved nutrients and metals, and modifies the optical properties of water bodies The contribution of DOM to global carbon budgets,... components is that DOM metabolism can affect nutrient balances of aquatic ecosystems In the simplest case, loadings of bioavailable dissolved organic carbon into nutrient-rich receiving waters can lead to significant conversion of inorganic nutrients to organic forms, changing the inorganic nutrient concentrations and ratios delivered to ecosystems further downstream Conversely, the organic nutrients... bacterial groups The control exerted by specific landscape elements (wetlands, certain soil characteristics) and hydrology on DOM delivery to aquatic ecosystems is becoming clearer, providing a nice example of how physical structure affects material movements among ecosystems Somewhat less appreciated are the mechanisms by which DOM can alter small-scale physical characteristics, ranging from light penetration... 18 References 19 I INTRODUCTION The photosynthetic production of dissolved organic matter (DOM) in marine and freshwater ecosystems is a major source of metabolic substrates 1 Present address: Department of Evolutionary Biology/Limnology Uppsala University, Uppsala, Sweden Aquatic Ecosystems: Interactivity of Dissolved Organic Matter Copyright 2002, Elsevier Science (USA) All rights of reproduction... microorganisms and influences both the activity and the composition of aquatic microbial communities (Pomeroy, 1974; Azam and Cho, 1987) Such internally produced (autochthonous) DOM is essentially derived from algae and macrophytes The algal component, which is typically dominated by phytoplankton in lentic ecosystems and periphyton in lotic ecosystems, has received the lion’s share of attention as an autochthonous... heterotrophic microorganisms or can be transformed to such substrates through various enzymatic and abiotic 1 Supply of Dissolved Organic Matter to Aquatic Ecosystems 5 FIGURE 1 Fate and major transformation pathways of phytoplankton- and macrophytederived DOM in aquatic systems Arrows indicate fluxes; POC denotes particulate organic matter; LMW and HMW DOM refer to the monomeric (low molecular weight) and... Structure Domain Biogeochemical Domain 430 Trophic Domain 439 Summary 448 References 449 426 Dissolved Organic Carbon: Detrital Energetics, Metabolic Regulators, and Drivers of Ecosystem Stability of Aquatic Ecosystems Robert G Wetzel I Introduction 455 II Seven Directions of DOM Thought and Understanding 461 References 475 20 Dissolved Organic Matter: Out of the Black Box into the Mainstream R L Sinsabaugh... Phosphorus) 388 IV Bacterial Physiology 389 V Dissolved Organic Matter Production Side 392 VI Conclusions 395 References 395 17 Patterns in Dissolved Organic Matter Lability and Consumption across Aquatic Ecosystems P A del Giorgio and J Davis I II III IV V VI VII VIII IX X XI Introduction 400 Data Collection 402 Data Analysis 405 Patterns of Dissolved Organic Matter Lability among Systems 407 Lability... influenced by, microbial communities This volume is organized into three major sections: (1) Sources and Composition, (2) Transformation and Regulation, and (3) Approaches to Synthesis DOM is supplied to aquatic ecosystems from both external (allochthonous) and internal (autochthonous) sources, and differences in the ultimate origin combined with differential transformation during transport may lead to significantly... 2002 “Biogeochemistry of Marine Dissolved Organic Matter.” Academic Press, San Diego SECTION ONE SOURCES AND COMPOSITION This Page Intentionally Left Blank 1 Supply of Dissolved Organic Matter to Aquatic Ecosystems: Autochthonous Sources Stefan Bertilsson*,1 and Jeremy B Jones, Jr.† *Department of Civil and Environmental Engineering Massachusetts Institute of Technology Cambridge, Massachusetts † Institute .