Microbial Loop' in Stratified Systems
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Freshwater Ecosystems and Biodiversity
Network of Conservation Educators & Practitioners Freshwater Ecosystems and Biodiversity Author(s): Nathaniel P. Hitt, Lisa K. Bonneau, Kunjuraman V. Jayachandran, and Michael P. Marchetti Source: Lessons in Conservation, Vol. 5, pp. 5-16 Published by: Network of Conservation Educators and Practitioners, Center for Biodiversity and Conservation, American Museum of Natural History Stable URL: ncep.amnh.org/linc/ This article is featured in Lessons in Conservation, the official journal of the Network of Conservation Educators and Practitioners (NCEP). NCEP is a collaborative project of the American Museum of Natural History’s Center for Biodiversity and Conservation (CBC) and a number of institutions and individuals around the world. Lessons in Conservation is designed to introduce NCEP teaching and learning resources (or “modules”) to a broad audience. NCEP modules are designed for undergraduate and professional level education. These modules—and many more on a variety of conservation topics—are available for free download at our website, ncep.amnh.org. To learn more about NCEP, visit our website: ncep.amnh.org. All reproduction or distribution must provide full citation of the original work and provide a copyright notice as follows: “Copyright 2015, by the authors of the material and the Center for Biodiversity and Conservation of the American Museum of Natural History. All rights reserved.” Illustrations obtained from the American Museum of Natural History’s library: images.library.amnh.org/digital/ SYNTHESIS 5 Freshwater Ecosystems and Biodiversity Nathaniel P. Hitt1, Lisa K. Bonneau2, Kunjuraman V. Jayachandran3, and Michael P. Marchetti4 1U.S. Geological Survey, Leetown Science Center, USA, 2Metropolitan Community College-Blue River, USA, 3Kerala Agricultural University, India, 4School of Science, St. -
Response of Marine Food Webs to Climate-Induced Changes in Temperature and Inflow of Allochthonous Organic Matter
Response of marine food webs to climate-induced changes in temperature and inflow of allochthonous organic matter Rickard Degerman Department of Ecology and Environmental Science 901 87 Umeå Umeå 2015 1 Copyright©Rickard Degerman ISBN: 978-91-7601-266-6 Front cover illustration by Mats Minnhagen Printed by: KBC Service Center, Umeå University Umeå, Sweden 2015 2 Tillägnad Maria, Emma och Isak 3 Table of Contents Abstract 5 List of papers 6 Introduction 7 Aquatic food webs – different pathways Food web efficiency – a measure of ecosystem function Top predators cause cascade effects on lower trophic levels The Baltic Sea – a semi-enclosed sea exposed to multiple stressors Varying food web structures Climate-induced changes in the marine ecosystem Food web responses to increased temperature Responses to inputs of allochthonous organic matter Objectives 14 Material and Methods 14 Paper I Paper II and III Paper IV Results and Discussion 18 Effect of temperature and nutrient availability on heterotrophic bacteria Influence of food web length and labile DOC on pelagic productivity and FWE Consequences of changes in inputs of ADOM and temperature for pelagic productivity and FWE Control of pelagic productivity, FWE and ecosystem trophic balance by colored DOC Conclusion and future perspectives 21 Author contributions 23 Acknowledgements 23 Thanks 24 References 25 4 Abstract Global records of temperature show a warming trend both in the atmosphere and in the oceans. Current climate change scenarios indicate that global temperature will continue to increase in the future. The effects will however be very different in different geographic regions. In northern Europe precipitation is projected to increase along with temperature. -
Bacterial Production and Respiration
Organic matter production % 0 Dissolved Particulate 5 > Organic Organic Matter Matter Heterotrophic Bacterial Grazing Growth ~1-10% of net organic DOM does not matter What happens to the 90-99% of sink, but can be production is physically exported to organic matter production that does deep sea not get exported as particles? transported Export •Labile DOC turnover over time scales of hours to days. •Semi-labile DOC turnover on time scales of weeks to months. •Refractory DOC cycles over on time scales ranging from decadal to multi- decadal…perhaps longer •So what consumes labile and semi-labile DOC? How much carbon passes through the microbial loop? Phytoplankton Heterotrophic bacteria ?? Dissolved organic Herbivores ?? matter Higher trophic levels Protozoa (zooplankton, fish, etc.) ?? • Very difficult to directly measure the flux of carbon from primary producers into the microbial loop. – The microbial loop is mostly run on labile (recently produced organic matter) - - very low concentrations (nM) turning over rapidly against a high background pool (µM). – Unclear exactly which types of organic compounds support bacterial growth. Bacterial Production •Step 1: Determine how much carbon is consumed by bacteria for production of new biomass. •Bacterial production (BP) is the rate that bacterial biomass is created. It represents the amount of Heterotrophic material that is transformed from a nonliving pool bacteria (DOC) to a living pool (bacterial biomass). •Mathematically P = µB ?? µ = specific growth rate (time-1) B = bacterial biomass (mg C L-1) P= bacterial production (mg C L-1 d-1) Dissolved organic •Note that µ = P/B matter •Thus, P has units of mg C L-1 d-1 Bacterial production provides one measurement of carbon flow into the microbial loop How doe we measure bacterial production? Production (∆ biomass/time) (mg C L-1 d-1) • 3H-thymidine • 3H or 14C-leucine Note: these are NOT direct measures of biomass production (i.e. -
Developments in Aquatic Microbiology
INTERNATL MICROBIOL (2000) 3: 203–211 203 © Springer-Verlag Ibérica 2000 REVIEW ARTICLE Samuel P. Meyers Developments in aquatic Department of Oceanography and Coastal Sciences, Louisiana State University, microbiology Baton Rouge, LA, USA Received 30 August 2000 Accepted 29 September 2000 Summary Major discoveries in marine microbiology over the past 4-5 decades have resulted in the recognition of bacteria as a major biomass component of marine food webs. Such discoveries include chemosynthetic activities in deep-ocean ecosystems, survival processes in oligotrophic waters, and the role of microorganisms in food webs coupled with symbiotic relationships and energy flow. Many discoveries can be attributed to innovative methodologies, including radioisotopes, immunofluores- cent-epifluorescent analysis, and flow cytometry. The latter has shown the key role of marine viruses in marine system energetics. Studies of the components of the “microbial loop” have shown the significance of various phagotrophic processes involved in grazing by microinvertebrates. Microbial activities and dissolved organic carbon are closely coupled with the dynamics of fluctuating water masses. New biotechnological approaches and the use of molecular biology techniques still provide new and relevant information on the role of microorganisms in oceanic and estuarine environments. International interdisciplinary studies have explored ecological aspects of marine microorganisms and their significance in biocomplexity. Studies on the Correspondence to: origins of both life and ecosystems now focus on microbiological processes in the Louisiana State University Station. marine environment. This paper describes earlier and recent discoveries in marine Post Office Box 19090-A. Baton Rouge, LA 70893. USA (aquatic) microbiology and the trends for future work, emphasizing improvements Tel.: +1-225-3885180 in methodology as major catalysts for the progress of this broadly-based field. -
Supplement A: Assumptions and Equations in Ecopath with Ecosim Governing Equations
Transactions of the American Fisheries Society 145:136–162, 2016 © American Fisheries Society 2016 DOI: 10.1080/00028487.2015.1069211 Supplement A: Assumptions and Equations in Ecopath with Ecosim Governing Equations The Ecopath module of EwE is a static, mass-balance ecosystem model that uses two governing equations for each species and age group (Christensen and Walters 2004). The first governing equation describes each species group’s production for a time period, i.e., production (P) is the sum of fishery catch (F), predation (M2), net migration (immigration, I, and emigration, E), biomass accumulation (BA), and mortality from other sources (‘other mortality’, M0): P = F + M2 + (I - E) + BA - M0 The second governing equation is based on the principle of conservation of matter within a group, and is designed to balance the energy flows of a biomass pool, i.e., consumption (C) equals the sum of production (P), respiration (R), and unassimilated food (U): C = P + R + U At a minimum, Ecopath requires inputs of diet composition (DCi,j, where i is predator and j is prey), fishery catch (Yi), and three of the following four parameters for each model group (i): biomass (Bi), production-to-biomass ratio (Pi/Bi), consumption-to-biomass ratio (Qi/Bi), and the ecotrophic efficiency (EEi, the fraction of the production that is used in the system and does not move directly to the detritus pool). Mass-balance principles are then used to estimate the fourth parameter. P/B is the annual production rate of the population in Ecopath. Under equilibrium conditions, the P/B ratio of fish is equivalent to its total annual instantaneous mortality (Z) (Allen 1971). -
Controls and Structure of the Microbial Loop
Controls and Structure of the Microbial Loop A symposium organized by the Microbial Oceanography summer course sponsored by the Agouron Foundation Saturday, July 1, 2006 Asia Room, East-West Center, University of Hawaii Symposium Speakers: Peter J. leB Williams (University of Bangor, Wales) David L. Kirchman (University of Delaware) Daniel J. Repeta (Woods Hole Oceanographic Institute) Grieg Steward (University of Hawaii) The oceans constitute the largest ecosystems on the planet, comprising more than 70% of the surface area and nearly 99% of the livable space on Earth. Life in the oceans is dominated by microbes; these small, singled-celled organisms constitute the base of the marine food web and catalyze the transformation of energy and matter in the sea. The microbial loop describes the dynamics of microbial food webs, with bacteria consuming non-living organic matter and converting this energy and matter into living biomass. Consumption of bacteria by predation recycles organic matter back into the marine food web. The speakers of this symposium will explore the processes that control the structure and functioning of microbial food webs and address some of these fundamental questions: What aspects of microbial activity do we need to measure to constrain energy and material flow into and out of the microbial loop? Are we able to measure bacterioplankton dynamics (biomass, growth, production, respiration) well enough to edu/agouroninstitutecourse understand the contribution of the microbial loop to marine systems? What factors control the flow of material and energy into and out of the microbial loop? At what scales (space and time) do we need to measure processes controlling the growth and metabolism of microorganisms? How does our knowledge of microbial community structure and diversity influence our understanding of the function of the microbial loop? Program: 9:00 am Welcome and Introductory Remarks followed by: Peter J. -
Micro-Food Web Structure Shapes Rhizosphere Microbial Communities and Growth in Oak
diversity Article Micro-Food Web Structure Shapes Rhizosphere Microbial Communities and Growth in Oak Hazel R. Maboreke ID , Veronika Bartel, René Seiml-Buchinger and Liliane Ruess * ID Institute of Biology, Ecology Group, Humboldt-Universität zu Berlin, Philippstraße 13, 10115 Berlin, Germany; [email protected] (H.R.M.); [email protected] (V.B.); [email protected] (R.S.-B.) * Correspondence: [email protected]; Tel.: +49-302-0934-9722 Received: 1 January 2018; Accepted: 11 March 2018; Published: 13 March 2018 Abstract: The multitrophic interactions in the rhizosphere impose significant impacts on microbial community structure and function, affecting nutrient mineralisation and consequently plant performance. However, particularly for long-lived plants such as forest trees, the mechanisms by which trophic structure of the micro-food web governs rhizosphere microorganisms are still poorly understood. This study addresses the role of nematodes, as a major component of the soil micro-food web, in influencing the microbial abundance and community structure as well as tree growth. In a greenhouse experiment with Pedunculate Oak seedlings were grown in soil, where the nematode trophic structure was manipulated by altering the proportion of functional groups (i.e., bacterial, fungal, and plant feeders) in a full factorial design. The influence on the rhizosphere microbial community, the ectomycorrhizal symbiont Piloderma croceum, and oak growth, was assessed. Soil phospholipid fatty acids were employed to determine changes in the microbial communities. Increased density of singular nematode functional groups showed minor impact by increasing the biomass of single microbial groups (e.g., plant feeders that of Gram-negative bacteria), except fungal feeders, which resulted in a decline of all microorganisms in the soil. -
Productivity Significant Ideas
2.3 Flows of Energy & Matter - Productivity Significant Ideas • Ecosystems are linked together by energy and matter flow • The Sun’s energy drives these flows and humans are impacting the flows of energy and matter both locally and globally Knowledge & Understandings • As solar radiation (insolation) enters the Earth’s atmosphere some energy becomes unavailable for ecosystems as the energy absorbed by inorganic matter or reflected back into the atmosphere. • Pathways of radiation through the atmosphere involve the loss of radiation through reflection and absorption • Pathways of energy through an ecosystem include: • Conversion of light to chemical energy • Transfer of chemical energy from one trophic level to another with varying efficiencies • Overall conversion of UB and visible light to heat energy by the ecosystem • Re-radiation of heat energy to the atmosphere. Knowledge & Understandings • The conversion of energy into biomass for a given period of time is measured by productivity • Net primary productivity (NPP) is calculated by subtracting respiratory losses (R) from gross primary productivity (GPP) NPP = GPP – R • Gross secondary productivity (GSP) is the total energy/biomass assimulated by consumers and is calculated by subtracting the mass of fecal loss from the mass of food eaten. GSP = food eaten – fecal loss • Net secondary productivity (NSP) is calculated by subtracting the respiratory losses (R) from GSP. NSP=GSP - R Applications and Skills • Analyze quantitative models of flows of energy and matter • Construct quantitative -
01 Delong 2-8 6/9/05 8:58 AM Page 2
01 Delong 2-8 6/9/05 8:58 AM Page 2 INSIGHT REVIEW NATURE|Vol 437|15 September 2005|doi:10.1038/nature04157 Genomic perspectives in microbial oceanography Edward F. DeLong1 and David M. Karl2 The global ocean is an integrated living system where energy and matter transformations are governed by interdependent physical, chemical and biotic processes. Although the fundamentals of ocean physics and chemistry are well established, comprehensive approaches to describing and interpreting oceanic microbial diversity and processes are only now emerging. In particular, the application of genomics to problems in microbial oceanography is significantly expanding our understanding of marine microbial evolution, metabolism and ecology. Integration of these new genome-enabled insights into the broader framework of ocean science represents one of the great contemporary challenges for microbial oceanographers. Marine ecosystems are complex and dynamic. A mechanistic under- greatly aid in these efforts. The correlation between organism- and habi- standing of the susceptibility of marine ecosystems to global environ- tat-specific genomic features and other physical, chemical and biotic mental variability and climate change driven by greenhouse gases will variables has the potential to refine our understanding of microbial and require a comprehensive description of several factors. These include biogeochemical process in ocean systems. marine physical, chemical and biological interactions including All these advances — improved cultivation, environmental genomic thresholds, negative and positive feedback mechanisms and other approaches and in situ microbial observatories — promise to enhance nonlinear interactions. The fluxes of matter and energy, and the our understanding of the living ocean system. Below, we provide a brief microbes that mediate them, are of central importance in the ocean, recent history of marine microbiology and outline some of the recent yet remain poorly understood. -
Global Biogeography of Fungal and Bacterial Biomass Carbon in Topsoil
UC Davis UC Davis Previously Published Works Title Global biogeography of fungal and bacterial biomass carbon in topsoil Permalink https://escholarship.org/uc/item/1mm4s4x3 Authors He, L Mazza Rodrigues, JL Soudzilovskaia, NA et al. Publication Date 2020-12-01 DOI 10.1016/j.soilbio.2020.108024 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Soil Biology and Biochemistry 151 (2020) 108024 Contents lists available at ScienceDirect Soil Biology and Biochemistry journal homepage: http://www.elsevier.com/locate/soilbio Global biogeography of fungal and bacterial biomass carbon in topsoil Liyuan He a, Jorge L. Mazza Rodrigues b, Nadejda A. Soudzilovskaia c, Milagros Barcelo´ c, Pål Axel Olsson d, Changchun Song e, Leho Tedersoo f, Fenghui Yuan a,g, Fengming Yuan h, David A. Lipson a, Xiaofeng Xu a,* a Biology Department, San Diego State University, San Diego, CA, 92182, USA b Department of Land, Air and Water Resources, University of California Davis, Davis, CA 95616, USA c Environmental Biology Department; Institute of Environmental Sciences, CML, Leiden University; Einsteinweg 2, 2333 CC Leiden, the Netherlands d Biodiversity, Biology Department, Lund University, SE-223 62 Lund, Sweden e Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China f Institute of Ecology and Earth Sciences, University of Tartu, 14a Ravila, 50411 Tartu, Estonia g Shenyang Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China h Oak Ridge National Laboratory, Environmental Sciences Division, Oak Ridge, TN, USA ARTICLE INFO ABSTRACT Keywords: Bacteria and fungi, representing two major soil microorganism groups, play an important role in global nutrient Fungi biogeochemistry. -
Numerical and Experimental Investigation of Equivalence Ratio (ER) and Feedstock Particle Size on Birchwood Gasification
energies Article Numerical and Experimental Investigation of Equivalence Ratio (ER) and Feedstock Particle Size on Birchwood Gasification Rukshan Jayathilake ID and Souman Rudra * Department of Engineering and Sciences, University of Agder, Grimstad 4879, Norway; [email protected] * Correspondence: [email protected]; Tel.: +47-3723-3036 Received: 13 July 2017; Accepted: 15 August 2017; Published: 19 August 2017 Abstract: This paper discusses the characteristics of Birchwood gasification using the simulated results of a Computational Fluid Dynamics (CFD) model. The CFD model is developed and validated with the experimental results obtained with the fixed bed downdraft gasifier available at the University of Agder (UIA), Norway. In this work, several parameters are examined and given importance, such as producer gas yield, syngas composition, lower heating value (LHV), and cold gas efficiency (CGE) of the syngas. The behavior of the parameters mentioned above is examined by varying the biomass particle size. The diameters of the two biomass particles are 11.5 mm and 9.18 mm. All the parameters investigate within the Equivalences Ratio (ER) range from 0.2 to 0.5. In the simulations, a variable air inflow rate is used to achieve different ER values. For the different biomass particle sizes, CO, CO2, CH4, and H2 mass fractions of the syngas are analyzed along with syngas yield, LHV, and CGE. At an ER value of 0.35, 9.18 mm diameter particle shows average maximum values of 60% of CGE and 2.79 Nm3/h of syngas yield, in turn showing 3.4% and 0.09 Nm3/h improvement in the respective parameters over the 11.5 mm diameter biomass particle. -
Microbial Loop Carbon Cycling in Ocean Environments Studied Using a Simple Steady-State Model
AQUATIC MICROBIAL ECOLOGY Vol. 26: 37–49, 2001 Published October 26 Aquat Microb Ecol Microbial loop carbon cycling in ocean environments studied using a simple steady-state model Thomas R. Anderson1,*, Hugh W. Ducklow2 1Southampton Oceanography Centre, Waterfront Campus, European Way, Southampton SO14 3ZH, United Kingdom 2College of William and Mary School of Marine Science, Rte 1208, Box 1346, Gloucester Point, Virginia 23062, USA ABSTRACT: A simple steady-state model is used to examine the microbial loop as a pathway for organic C in marine systems, constrained by observed estimates of bacterial to primary production ratio (BP:PP) and bacterial growth efficiency (BGE). Carbon sources (primary production including extracellular release of dissolved organic carbon, DOC), cycling via zooplankton grazing and viral lysis, and sinks (bacterial and zooplankton respiration) are represented. Model solutions indicate that, at least under near steady-state conditions, recent estimates of BP:PP of about 0.1 to 0.15 are consistent with reasonable scenarios of C cycling (low BGE and phytoplankton extracellular release) at open ocean sites such as the Sargasso Sea and subarctic North Pacific. The finding that bacteria are a major (50%) sink for primary production is shown to be consistent with the best estimates of BGE and dissolved organic matter (DOM) production by zooplankton and phytoplankton. Zooplank- ton-related processes are predicted to provide the greatest supply of DOC for bacterial consumption. The bacterial contribution to C flow in the microbial loop, via bacterivory and viral lysis, is generally low, as a consequence of low BGE. Both BP and BGE are hard to quantify accurately.