Ecosystem

About: Ecosystem is a research topic. Over the lifetime, 25460 publications have been published within this topic receiving 1291375 citations. The topic is also known as: ecological system & Ecosystem.

Microbial colonization and controls in dryland systems

Abstract: Drylands constitute the most extensive terrestrial biome, covering more than one-third of the Earth's continental surface. In these environments, stress limits animal and plant life, so life forms that can survive desiccation and then resume growth following subsequent wetting assume the foremost role in ecosystem processes. In this Review, we describe how these organisms assemble in unique soil- and rock-surface communities to form a thin veneer of mostly microbial biomass across hot and cold deserts. These communities mediate inputs and outputs of gases, nutrients and water from desert surfaces, as well as regulating weathering, soil stability, and hydrological and nutrient cycles. The magnitude of regional and global desert-related environmental impacts is affected by these surface communities; here, we also discuss the challenges for incorporating the consideration of these communities and their effects into the management of dryland resources.

Biodiversity at multiple trophic levels is needed for ecosystem multifunctionality

Abstract: Many experiments have shown that loss of biodiversity reduces the capacity of ecosystems to provide the multiple services on which humans depend. However, experiments necessarily simplify the complexity of natural ecosystems and will normally control for other important drivers of ecosystem functioning, such as the environment or land use. In addition, existing studies typically focus on the diversity of single trophic groups, neglecting the fact that biodiversity loss occurs across many taxa and that the functional effects of any trophic group may depend on the abundance and diversity of others. Here we report analysis of the relationships between the species richness and abundance of nine trophic groups, including 4,600 above- and below-ground taxa, and 14 ecosystem services and functions and with their simultaneous provision (or multifunctionality) in 150 grasslands. We show that high species richness in multiple trophic groups (multitrophic richness) had stronger positive effects on ecosystem services than richness in any individual trophic group; this includes plant species richness, the most widely used measure of biodiversity. On average, three trophic groups influenced each ecosystem service, with each trophic group influencing at least one service. Multitrophic richness was particularly beneficial for 'regulating' and 'cultural' services, and for multifunctionality, whereas a change in the total abundance of species or biomass in multiple trophic groups (the multitrophic abundance) positively affected supporting services. Multitrophic richness and abundance drove ecosystem functioning as strongly as abiotic conditions and land-use intensity, extending previous experimental results to real-world ecosystems. Primary producers, herbivorous insects and microbial decomposers seem to be particularly important drivers of ecosystem functioning, as shown by the strong and frequent positive associations of their richness or abundance with multiple ecosystem services. Our results show that multitrophic richness and abundance support ecosystem functioning, and demonstrate that a focus on single groups has led to researchers to greatly underestimate the functional importance of biodiversity.

Ecosystem Processes Along an Urban-to-Rural Gradient

Abstract: In order to understand the effect of urban development on the functioning of forest ecosystems during the past decade we have been studying red oak stands located on similar soil along an urban-rural gradient running from New York City ro rural Litchfield County, Connecticut. This paper summarizes the results of this work. Field measurements, controlled laboratory experiments, and reciprocal transplants documented soil pollution, soil hydrophobicity, litter decomposition rates, total soil carbon, potential nitrogen mineralization, nitrification, fungal biomass, and earthworm populations in forests along the 140 × 20 km study transect. The results revealed a complex urban-rural environmental gradient. The urban forests exhibit unique ecosystem structure and function in relation to the suburban and rural forest stands; these are likely linked to stresses of the urban environment such as air pollution, which has also resulted in elevated levels of heavy metals in the soil, the positive effects of the heat island phenomenon, and the presence of earthworms. The data suggest a working model to guide mechanistic work on the ecology of forests along urban-to-rural gradients, and for comparison of different metropolitan areas.

Coastal Ecosystem Processes

Abstract: Introduction Beaches and Tidal Flats Introduction Food Chains, Energy, and Carbon Flow Nitrogen Cycling Linkages to Physical Processes Mangroves and Salt Marshes Introduction Global Trends in Plant Biomass and Primary Production Factors Limiting Plant Production and Growth Food Webs and Decomposition Processes Nitrogen Flow Outwelling Seaweed and Seagrass Ecosystems Introduction Standing Crop and Primary Productivity Photosynthesis and Whole-Plant Carbon Balance Limiting Factors The Role of Grazers Detritus and Mineralization Processes Ecosystem Budgets Carbon Balance: Export and Links to Adjacent Systems Coral Reefs Introduction Sources of Carbon Production The Fate of Organic Matter Nitrogen and Phosphorus: Cycles and Limitation The Coral Factory: Carbon and Energy Budgets Systems-Level Perspectives: Models and Budgets The Role of Coral Reefs in the Tropical Biosphere The Coastal Ocean I The Coastal Zone Introduction The Coastal Ocean Defined What Is an Estuary? Hydrographic Classification of Coastal Systems Coastal Plain Estuaries, Tidal Lagoons, and Bays (Types IV, V, and VI) Coastal Lagoons (Type VII) River-Dominated Systems (Types I, II, and III) The Coastal Ocean II The Shelf Proper and Shelf Edge Introduction Shelf-Sea Fronts Along- and Across-Shelf Gradients Processes at the Shelf Edge Nutrient Cycles and Global Change in the Coastal Ocean Global Estimates of Fishery Yields to Humans Degradation and Conservation A Glimpse at the Global Problem Eutrophication Habitat Modification and Destruction Restoration Attempts: Problems and Progress Sustainability: Implications for Management Conservation: Tools and Impediments Global Climate Change: Coastal Implications A Final Remark References Index

Abyssal food limitation, ecosystem structure and climate change

Abstract: The abyssal seafloor covers more than 50% of the Earth and is postulated to be both a reservoir of biodiversity and a source of important ecosystem services. We show that ecosystem structure and function in the abyss are strongly modulated by the quantity and quality of detrital food material sinking from the surface ocean. Climate change and human activities (e.g. successful ocean fertilization) will alter patterns of sinking food flux to the deep ocean, substantially impacting the structure, function and biodiversity of abyssal ecosystems. Abyssal ecosystem response thus must be considered in assessments of the environmental impacts of global warming and ocean fertilization.