DOCSLIB.ORG

Detritus: Mother Nature’S Rice Cake

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Detritus: Mother Nature’S Rice Cake Detritus: Mother Natures Rice Cake Pamela Mason and Lyle Varnell Detritus has been studied since ancient times. gested that man should devise ways to use de- Early man and ancient civilizations considered tritus as food (Odum 1969). muds and slimes the source and sustenance of all aquatic life (Darnell 1967). Early civilizations The importance of detritus as the basis of eco- which relied on the bounties of the sea for nutri- system foodwebs has been researched exten- tion and commerce, and which worshipped ele- sively. In estuarine foodwebs particularly, sci- ments within the entific studies indi- oceans, highly cate that detritus revered detritus. serves as a food source for micro- While todays scopic organisms, popular opinion which in turn are con- appears to sim- sumed by larger or- ply discount the ganisms, forming the importance of de- basis for the estua- tritus as just rine foodweb. As will plain mud, sci- be discussed in this entific evidence paper, and a second, indicates that more detailed paper the ancient cul- to follow, the estua- tures may have rine detrital foodweb been correct con- is fairly complex, yet cerning the im- fundamentally based portance of detri- on the decay of veg- tus. Detritus is etative matter provid- important on a ing a growing sub- global scale as strate for microbes well as locally; which are a food from its role in source for larger ani- the world carbon mals. In turn, these cycle to supplying animals are prey for part of the nutri- larger animals and tional require- eventually, recreation- ments of a ally and commercially marsh peri- important finfish, winkle (Stumm shellfish, crusta- & Morgan 1981, ceans, waterfowl and Baker & Allen wading birds. 1977). It has even been sug- 1 What is Detritus? be limited to the organic matter, the material which is being broken down, and should exclude Detritus, derived from the Latin root meaning to the microorganisms which are the agents of break down or wear away, is used to define or- breaking down the substrate. However, a more ganic muds, slimes and oozes. Early efforts by functional definition of detritus includes atten- the scientific community to define detritus re- dant microorganisms with the organic debris. sulted in very general definitions. Darnell (1961) As much of the current interest in detritus re- defined detritus as all types of biogenic mate- lates to the role it plays in marine foodwebs, rial in various stages of bacterial decomposition. and as microorganisms are a fundamental ele- Later, Darnell (1967) modified his definition to ment of that role, we will use the functional defi- all types of biogenic material in various stages nition which includes attendant microorgan- of microbial decomposition which represent po- isms. tential energy sources for consumer species. However, further efforts by the scientific com- Using any definition, detritus is found in all munity to define detritus were hampered by the biotopes. This report will address the marine philosophical debate over the inclusion, or ex- environment only, and specifically, the estuarine clusion, of microorganisms. In one school of and marsh environment. thought, detritus refers to organic debris to- gether with attendant microorganisms, while another school of thought defines the substance What is in Detritus: Composition as detritus plus attendant microorganisms Detritus can be composed of a diverse suite of (Crosby 1985). In other words, is detritus the living and non-living constituents. The gross non-living organic debris (vegetative matter and composition of marine detritus includes particu- feces) alone, or does it include the living micro- late vascular plant matter, Monerans (blue-green organisms? Classically, the definition should algae and bacteria), yeasts and other fungi, al- gae (benthic and phytoplankton), carcasses, fe- ces, bacterial exopolymers, protozoans (ciliates and zooflagellates), metazoans (nematodes, tur- Wetlands Program bellarians, rotifers, ostracods, and harp- School of Marine Science acticoids), shed exoskeletons, regurgitations, Virginia Institute of Marine Science molecular aggregates (colloidal lipids, carbohy- College of William and Mary drates and proteins), dissolved liquids (vita- Gloucester Point, Virginia 23062 mins, amino acids, simple sugars, and urea), and dissolved gases (methane, ammonia, and Dr. Carl Hershner, Program Director hydrogen sulfide) (various authors). Mr. Thomas A. Barnard, Jr., Editor Dr. Kirk Havens, Editor Fecal matter is a relatively important component Published by: VIMS Publication Center of detritus. Fecal pellets are a major marine food source which is high in protein, and ingestion This technical report was funded, in part, by the and use of such is an important marine energy Virginia Coastal Resources Management Program of transfer mechanism (Frankenberg & Smith 1967, the Dept. of Environmental Quality through Grant Johannes & Satomi 1967). #NA57OZ0561-01 of the National Oceanic and At- mospheric Administration, Office of Ocean and Coastal Resources Manage- Where Does Detritus Come From: ment, under the Coastal Zone Manage- Sources ment Act of 1972, as amended. Natural sources of marine detritus include ani- The views expressed herein are those of the mals, phytoplankton, bacteria and blue green authors and do not necessarily reflect the views of algae, periphyton, submerged aquatic vegeta- NOAA or any of its subagencies or DEQ. tion, intertidal macrophytes, river borne detri- tus, beach and shore material, terrestrial detri- Commonwealths Declared Policy: to preserve the wet- tus and atmospheric deposition (Darnell 1967 lands and to prevent their despoliation and destruction... and others). Detritus is produced during all sea- sons and is available in three forms: particu- Printed on recycled paper. late, micellar (organic material adsorbed onto 2 inorganic particles), and dissolved (Darnell proximately equal to phytoplankton (770 g m2y1) 1961, Odum & de la Cruz 1967). Particulate and terrestrial (600 g m-2y-1) sources for a Geor- forms can either be suspended in the water col- gia salt marsh. umn or precipitated. The sources of particulate detritus can be determined by chemical testing, as sources have distinct signatures. The im- How is Detritus Produced? portance of each source varies with area, salin- ity and season. There is little scientific information on the decay rate of salt marsh vegetation. However, some The great bulk of organic detritus is derived from research has been undertaken to study the pro- vegetation. The majority of vegetative material duction of detritus from Spartina alterniflora. in salt marshes is of macrophyte origin. Since approximately 2/3 of the primary produc- Spartina alterniflora and algal species are the tion of east coast intertidal marshes is derived two major sources of primary production in salt from Spartina alterniflora (Pomeroy et al. 1981), marshes, but algal production is estimated to a discussion of these processes is particularly be only 20-25% of relevant. marsh grass pro- Most halophytes, duction. Esti- Ash Free Dry Weight is the determination of mass af- Spartina alterniflora mates of aerial ter the removal of water and carbonaceous material. It included, are physi- production for is commonly used to determine the mass of the struc- ologically patterned Spartina alterni- tural components of living matter, or the organic car- much like terrestrial flora range from bon content of soils. There are several techniques by plants (Haines & 550-2,000 grams which this determination may be made. In the most Montague 1979). per meter square simple technique, a sample is ignited (burned) at high -2 -1 Therefore, marsh per year (g m y ) temperature. Prior to ignition, the material is placed in grass detritus is com- dry weight with a low temperature oven, commonly referred to as a dry- posed primarily of below-ground ing oven, to remove the water content of the material. structural plant production up to The material is then weighed (dry weight) and placed in o polymers such as cel- 7 times aerial a high temperature (550 C) muffle furnace for a couple lulose, hemicellu- production (Mar- hours. At this temperature the organic material is lose and lignin. inucci 1982). burned off and the structural material remains. With These polymers are This far exceeds vegetative samples, the ash residue is calculated, and collectively referred to marsh phyto- in soils the loss-on-ignition (the difference between the as lignocellulose plankton or ben- dry weight and ash free dry weight) provides a rough (Benner et al. 1988, thic algae produc- estimate of organic carbon. (Allen et al. 1986) tion. However, Hodson et al. 1984). there is an in- Lignocellulose consti- crease in benthic algae production during win- tutes from 55-80% of the ash free dry weight of above-ground Spartina alterniflora biomass ter months when the senescence of the marsh grasses allows light to penetrate a greater area (Coston-Clements & Ferguson 1985, Benner et of the marsh surface (Gallagher & Daiber 1974, al. 1988). (See box above.) Lignin, starch and Peterson & Howarth 1987, Van Raalte et al. 1976, lipids make up the remaining percentage of the Benner et al. 1988). above-ground biomass, but can make up a greater percentage of ash free dry weight than Mann (1976) estimates that a maximum of 10% either cellulose or hemicellulose in the below- of marine macrophyte (both emergent and sub- ground portion of Spartina alterniflora (Coston- merged aquatic) production is directly consumed Clements & Ferguson 1985, Newell & Langdon by primary consumers and the remaining 90%, 1986). Spartina alterniflora lignocellulose, by or more, enters detritus food chains. Studies in weight, is approximately 41% carbon and <1% a Georgia estuary estimate that of the total de- nitrogen (Benner et al. 1988). trital pool, approximately 86% of the detritus was decaying Spartina alterniflora (Odum & de Valiela et al. (1985) showed decay rate to be di- la Cruz 1967). Hodson et al. (1984) showed rectly related to internal nitrogen levels of the annual detrital production from Spartina decaying material, generally the higher the nitro- alterniflora to be approximately 1,200 g m-2y-1.
Load more

Recommended publications
  • Altered Organic Matter Dynamics in Rivers and Streams: Ecological Consequences and Management Implications
    Limnetica, 29 (2): x-xx (2011) Limnetica, 35 (2): 303-322 (2016). DOI: 10.23818/limn.35.25 c Asociación Ibérica de Limnología, Madrid. Spain. ISSN: 0213-8409 Altered organic matter dynamics in rivers and streams: ecological consequences and management implications Arturo Elosegi and Jesús Pozo Faculty of Science and Technology, the University of the Basque Country UPV/EHU, PoBox 644, 48080 Bilbao, Spain. ∗ Corresponding author: [email protected] 2 Received: 15/02/2016 Accepted: 05/05/2016 ABSTRACT Altered organic matter dynamics in rivers and streams: ecological consequences and management implications Scientists have spent decades measuring inputs, storage and breakdown of organic matter in freshwaters and have documented the effects of soil uses, pollution, climate warming or flow regulation on these pivotal ecosystem functions. Large-scale collaborative experiments and meta-analyses have revealed some clear patterns as well as substantial variability in detritus dynamics, and a number of standardized methods have been designed for routine monitoring of organic matter inputs, retention and breakdown in different conditions. Despite the knowledge gathered, scientists have been relatively ineffective at convincing managers of the importance of organic matter dynamics in freshwaters. Here we review the existing information of the role of organic matter as a) an element structuring freshwater habitats, b) a source or sink of nutrients, c) a food resource for heterotrophs, d) a source of pollution, e) a modulator of the fate of pollutants, f) a source of greenhouse gases, g) a potential source of environmental problems, and h) a diagnostic tool for ecosystem functioning. Current knowledge in some of these points is enough to be transferred to management actions, although has seldom been so.
    [Show full text]
  • 7.014 Handout PRODUCTIVITY: the “METABOLISM” of ECOSYSTEMS
    7.014 Handout PRODUCTIVITY: THE “METABOLISM” OF ECOSYSTEMS Ecologists use the term “productivity” to refer to the process through which an assemblage of organisms (e.g. a trophic level or ecosystem assimilates carbon. Primary producers (autotrophs) do this through photosynthesis; Secondary producers (heterotrophs) do it through the assimilation of the organic carbon in their food. Remember that all organic carbon in the food web is ultimately derived from primary production. DEFINITIONS Primary Productivity: Rate of conversion of CO2 to organic carbon (photosynthesis) per unit surface area of the earth, expressed either in terns of weight of carbon, or the equivalent calories e.g., g C m-2 year-1 Kcal m-2 year-1 Primary Production: Same as primary productivity, but usually expressed for a whole ecosystem e.g., tons year-1 for a lake, cornfield, forest, etc. NET vs. GROSS: For plants: Some of the organic carbon generated in plants through photosynthesis (using solar energy) is oxidized back to CO2 (releasing energy) through the respiration of the plants – RA. Gross Primary Production: (GPP) = Total amount of CO2 reduced to organic carbon by the plants per unit time Autotrophic Respiration: (RA) = Total amount of organic carbon that is respired (oxidized to CO2) by plants per unit time Net Primary Production (NPP) = GPP – RA The amount of organic carbon produced by plants that is not consumed by their own respiration. It is the increase in the plant biomass in the absence of herbivores. For an entire ecosystem: Some of the NPP of the plants is consumed (and respired) by herbivores and decomposers and oxidized back to CO2 (RH).
    [Show full text]
  • Salt Marsh Food Web a Food Chain Shows How Each Living Thing Gets Its Food
    North Carolina Aquariums Education Section Salt Marsh Food Web A food chain shows how each living thing gets its food. Some animals eat plants and some animals eat other animals. For example, a simple food chain links the plants, snails (that eats the plants), and the birds (that eat the snails). Each link in this chain is food for the next link. Food Webs are networks of several food chains. They show how plants and animals are connected in many ways to help them all survive. Below are some helpful terms associated with food chains and food webs. Helpful Terms Ecosystem- is a community of living and non-living things that work together. Producers- are plants that make their own food or energy. Consumers-are animals, since they are unable to produce their own food, they must consume (eat) plants or animals or both. There are three types of consumers: Herbivores-are animals that eat only plants. Carnivores- are animals that eat other animals. Omnivores- are animals that eat both plants and animals. Decomposers-are bacteria or fungi which feed on decaying matter. They are very important for any ecosystem. If they weren't in the ecosystem, the plants would not get essential nutrients, and dead matter and waste would pile up. Salt Marsh Food Web Activities The salt marsh houses many different plants and animals that eat each other, which is an intricately woven web of producers, consumers, and decomposers. Consumers usually eat more than one type of food, and they may be eaten by many other consumers. This means that several food chains become connected together to form a food web.
    [Show full text]
  • Detrital Food Chain As a Possible Mechanism to Support the Trophic Structure of the Planktonic Community in the Photic Zone of a Tropical Reservoir
    Limnetica, 39(1): 511-524 (2020). DOI: 10.23818/limn.39.33 © Asociación Ibérica de Limnología, Madrid. Spain. ISSN: 0213-8409 Detrital food chain as a possible mechanism to support the trophic structure of the planktonic community in the photic zone of a tropical reservoir Edison Andrés Parra-García1,*, Nicole Rivera-Parra2, Antonio Picazo3 and Antonio Camacho3 1 Grupo de Investigación en Limnología Básica y Experimental y Biología y Taxonomía Marina, Instituto de Biología, Universidad de Antioquia. 050010 Medellín, Colombia. 2 Grupo de Fundamentos y Enseñanza de la Física y los Sistemas Dinámicos, Instituto de Física, Universidad de Antioquia. 050010 Medellín, Colombia. 3 Instituto Cavanilles de Biodiversidad y Biología Evolutiva. Universidad de Valencia. E–46980 Paterna, Valencia. España. * Corresponding author: [email protected] Received: 31/10/18 Accepted: 10/10/19 ABSTRACT Detrital food chain as a possible mechanism to support the trophic structure of the planktonic community in the photic zone of a tropical reservoir In the photic zone of aquatic ecosystems, where different communities coexist showing different strategies to access one or different resources, the biomass spectra can describe the food transfers and their efficiencies. The purpose of this work is to describe the biomass spectrum and the transfer efficiency, from the primary producers to the top predators of the trophic network, in the photic zone of the Riogrande II reservoir. Data used in the model of the biomass spectrum were taken from several studies carried out between 2010 and 2013 in the reservoir. The analysis of the slope of a biomass spectrum, of the transfer efficiencies, and the omnivory indexes, suggest that most primary production in the photic zone of the Riogrande II reservoir is not directly used by primary consumers, and it appears that detritic mass flows are an indirect way of channeling this production towards zooplankton.
    [Show full text]
  • Development Team Prof
    Paper No: 01 Ecosystem Structures & Functions Module 5: Food chains and Food webs Development Team Prof. R.K. Kohli Principal Investigator & Prof. V.K. Garg & Prof. Ashok Dhawan Co- Principal Investigator Central University of Punjab, Bathinda Dr. Renuka Gupta, YMCA University of Science Paper Coordinator and Technology, Faridabad, Haryana Dr. Renuka Gupta, YMCA University of Science Content Writer and Technology, Faridabad, Haryana Content Reviewer Prof. V. K. Garg, Central University of Punjab, Bathinda 1 Anchor Institute Central University of Punjab Ecosystem Structures & Functions Environmental Module 5: Food Chains and Food Webs Sciences Description of Module Subject Name Environmental Sciences Paper Name Ecosystem Structure & Function Module 5. Food Chains and Food webs Name/Title Module Id EVS/ESF-I/5 Pre-requisites • To learn about food chains and food web in an ecosystem. • To understand about grazing and detritus food chains. Objectives • To learn about different types of food webs. • To understand special features and significance of food chains and food web Ecosystem, Food chain, Food web, Grazing food chain, Detritus food chain, Types Keywords of food web, Reward Feedback, Trophic Cascades, Keystone Predation, Bottom - up approach, Top - down approach, Bioaccumulation, Biomagnification. 2 Ecosystem Structures & Functions Environmental Module 5: Food Chains and Food Webs Sciences Module 5: Food Chains and Food Webs Contents 1. Introduction 2. Food Chains 3. Types of Food Chains 4. Food Webs 5. Types of Food webs 6. Characteristics of food webs 7. Significance of food chains and food webs 8. Biomagnification 5. 1 Introduction Every ecosystem works in a systematic manner under natural conditions. It receives energy from the sun and passes it to various biotic components.
    [Show full text]
  • Nutrient Release Rates and Ratios by Two Stream Detritivores Fed Leaf Litter Grown Under Elevated Atmospheric CO2
    Arch. Hydrobiol. 163 4 463–477 Stuttgart, August 2005 Nutrient release rates and ratios by two stream detritivores fed leaf litter grown under elevated atmospheric CO2 Paul C. Frost1 * and Nancy C. Tuchman2 With 5 figures and 1 table Abstract: We examined how nutrient release by two common stream detritivores, Asellus and Gammarus, was affected by the consumption of aspen leaf litter from trees grown under elevated CO2. We measured excretory release of dissolved organic carbon (DOC), ammonia (NH4), and soluble reactive phosphorus (SRP) from consumers fed senesced leaves of Populus tremuloides (trembling aspen) trees grown under elevated (720 ppm) and ambient (360 ppm) CO2. Contrary to predictions based on ecological stoichiometry, elevated CO2 leaves caused greater NH4 and SRP release from both ani- mals but did not affect the release of DOC. Elevated CO2 leaves reduced DOC : NH4 and DOC : SRP ratios released from Asellus but did not affect these ratios from Gam- marus. Both animals showed lower NH4 : SRP release ratios after eating elevated CO2 leaves. A mass balance model of consumer N and P release demonstrated that in- creased excretion rates likely resulted from reduced absorption efficiencies (and un- changed or higher digestive efficiencies) in these aquatic detritivores. Our results indi- cate that changes in leaf biochemistry resulting from elevated atmospheric CO2 will strongly affect the ability of stream consumers to retain important biogenic elements. Increased release rates of NH4 and SRP are another indication, along with reduced growth and reproduction, that litter produced under elevated CO2 has strong effects on key physiological processes in detritivores with potentially strong consequences for nutrient cycling in streams of forested regions.
    [Show full text]
  • Detritus Dynamics in the Seagrass Posidonia Oceanica: Elements for an Ecosystem Carbon and Nutrient Budget
    MARINE ECOLOGY PROGRESS SERIES Vol. 151: 43-53, 1997 Published May 22 Mar Ecol Prog Ser Detritus dynamics in the seagrass Posidonia oceanica: elements for an ecosystem carbon and nutrient budget M. A. Mateo*, J. Romero Departament d'Ecologia, Universitat de Barcelona, Diagonal 645, E-08028 Barcelona, Spain ABSTRACT. Leaf decay, leaf l~tterexport, burial in belowground sinks, and resp~ratoryconsumption of detritus were exam~nedat 2 different depths in a Posidonia oceanica (L ) Delile meadow off the Medes Islands, NW Mediterranean. At 5 m, the amount of exported leaf litter represented carbon, nitrogen and phosphorus losses of 7. 9 and 6%)of the plant primary productlon, respectively. About 26% of the carbon produced by the plant in 1 yr was immobilized by burial in the belowground compartment, i.e. as roots and rhizomes. Annual nitrogen and phosphorus burial in the sediment was 8 and 5",, of total N and P needs, respectively. Respiratory consumption (aerobic) of carbon leaf detritus represented 17"" of the annual production. An additional, but very substantial, loss of carbon as very fine particulate organic matter has been estimated at ca 48%. At 13 m the pattern of carbon losses was similar, but the lesser effect of wave action (reldtive to that at 5 m) reduced exportation, hence increasing the role of respiratory consumption. Data on carbon losses indicated that only a small part of the plant productlon was actually available to fuel the food web of this ecosystem. Total nutrient losses were in the range of 21 to 47 ",I of annual needs. From differences found in N and P concentrations between liv~ngand dead tissues, it is suggested that important nutrient recycling (50 to 70%)) may be due either to reclamation or to leaching immediately after plant death.
    [Show full text]
  • And Detritus-Based Food Chain in the Micro-Food Web of an Arable Soil by Plant Removal
    RESEARCH ARTICLE Disentangling the root- and detritus-based food chain in the micro-food web of an arable soil by plant removal Olena Glavatska1, Karolin MuÈ ller2, Olaf Butenschoen3, Andreas Schmalwasser4, Ellen Kandeler2, Stefan Scheu3,5, Kai Uwe Totsche4, Liliane Ruess1* 1 Institute of Biology, Ecology Group, Humboldt-UniversitaÈt zu Berlin, Berlin, Germany, 2 Institute of Soil Science and Land Evaluation, Soil Biology Department, University of Hohenheim, Stuttgart, Germany, 3 J.F. Blumenbach Institute of Zoology and Anthropology, Georg August University of GoÈttingen, GoÈttingen, a1111111111 Germany, 4 Institute of Geosciences, Hydrogeology Section, Friedrich Schiller University of JenaJena, a1111111111 Germany, 5 Centre of Biodiversity and Sustainable Land Use, University of GoÈttingen, GoÈttingen, Germany a1111111111 a1111111111 * [email protected] a1111111111 Abstract Soil food web structure and function is primarily determined by the major basal resources, OPEN ACCESS which are living plant tissue, root exudates and dead organic matter. A field experiment was Citation: Glavatska O, MuÈller K, Butenschoen O, performed to disentangle the interlinkage of the root-and detritus-based soil food chains. An Schmalwasser A, Kandeler E, Scheu S, et al. (2017) arable site was cropped either with maize, amended with maize shoot litter or remained Disentangling the root- and detritus-based food chain in the micro-food web of an arable soil by bare soil, representing food webs depending on roots, aboveground litter and soil organic plant removal. PLoS ONE 12(7): e0180264. https:// matter as predominant resource, respectively. The soil micro-food web, i.e. microorganisms doi.org/10.1371/journal.pone.0180264 and nematodes, was investigated in two successive years along a depth transect.
    [Show full text]
  • Ecosystem Ecology Living Organisms and Their Non Living (Abiotic) Environment Are Interrelated and Interact with Each Other
    1 | P a g e Ecosystem Ecology Living organisms and their non living (abiotic) environment are interrelated and interact with each other. The term ‘ecosystem’ was proposed by A. G. Tansley and it was defined as the system resulting from the integration of all living and non living factors of the environment. Some parallel terms such as biocoenosis, microcosm, geobiocoenosis, holecoen, biosystem, bioenert body and ecosom were used for each ecological systems. However, the term ‘ecosystem’ is most preferred, where ‘eco’ stands for the environment, and ‘system’ stands for an interacting, interdependent complex. Any unit that includes all the organisms, i.e. communities, in a given area, interacts with the physical environment so that a flow of energy leads to a clearly defined trophic structure, biotic diversity and material cycle within the system, is known as an ecological system or ecosystem. It is usually an open system with regular but variable influx and loss of materials and energy. It is a basic functional unit with unlimited boundaries. Types of ecosystems The ecosystems can be broadly divided into the following two types; 1. Natural ecosystems 2. Artificial (man cultured ecosystems Natural ecosystems The ecosystems which are self-operating under natural conditions with any interference by man, are known as natural ecosystems. These ecosystems may be classified as follows: 1. Terrestrial ecosystems, e.g. Forests, grasslands and deserts 2. Aquatic ecosystems, which may be further classified as i) Freshwater: ecosystem, which in turn is divided into lentic (running water like streams, springs, rivers, etc.) and lentic (standing water like lakes, bonds, pools, swamps, ditches, etc.) ii) Marine ecosystem, e.g.
    [Show full text]
  • Title: the Detritus-Based Microbial-Invertebrate Food Web
    1 Title: 2 3 The detritus-based microbial-invertebrate food web contributes disproportionately 4 to carbon and nitrogen cycling in the Arctic 5 6 7 8 Authors: 9 Amanda M. Koltz1*, Ashley Asmus2, Laura Gough3, Yamina Pressler4 and John C. 10 Moore4,5 11 1. Department of Biology, Washington University in St. Louis, Box 1137, St. 12 Louis, MO 63130 13 2. Department of Biology, University of Texas at Arlington, Arlington, TX 14 76109 15 3. Department of Biological Sciences, Towson University, Towson, MD 16 21252 17 4. Natural Resource Ecology Laboratory, Colorado State University, Ft. 18 Collins, CO 80523 USA 19 5. Department of Ecosystem Science and Sustainability, Colorado State 20 University, Ft. Collins, CO 80523 USA 21 *Correspondence: Amanda M. Koltz, tel. 314-935-8794, fax 314-935-4432, 22 e-mail: [email protected] 23 24 25 26 Type of article: 27 Submission to Polar Biology Special Issue on “Ecology of Tundra Arthropods” 28 29 30 Keywords: 31 Food web structure, energetic food web model, nutrient cycling, C mineralization, 32 N mineralization, invertebrate, Arctic, tundra 33 1 34 Abstract 35 36 The Arctic is the world's largest reservoir of soil organic carbon and 37 understanding biogeochemical cycling in this region is critical due to the potential 38 feedbacks on climate. However, our knowledge of carbon (C) and nitrogen (N) 39 cycling in the Arctic is incomplete, as studies have focused on plants, detritus, 40 and microbes but largely ignored their consumers. Here we construct a 41 comprehensive Arctic food web based on functional groups of microbes (e.g., 42 bacteria and fungi), protozoa, and invertebrates (community hereafter referred to 43 as the invertebrate food web) residing in the soil, on the soil surface and within 44 the plant canopy from an area of moist acidic tundra in northern Alaska.
    [Show full text]
  • III.9 Ecosystem Productivity and Carbon Flows: Patterns Across Ecosystems Julien Lartigue and Just Cebrian
    III.9 Ecosystem Productivity and Carbon Flows: Patterns across Ecosystems Julien Lartigue and Just Cebrian OUTLINE by fitting the following single exponential equation to the pattern of detritus decay observed in experi- 1. Nature of carbon budgets mental incubations, DM ¼ DM eÀ k(t À t0), where 2. Rationale and approach for studying patterns of t t0 k is the decomposition rate, DM is the detrital ecosystem productivity and carbon flow t mass remaining in the experimental incubation at 3. Patterns in ecosystem productivity and carbon time t,DM is the initial detrital mass, and (tÀt )is flow t0 0 the incubation time 4. Conclusion detrital production. The amount (in g CÁmÀ2ÁyearÀ1)of net primary production not consumed by herbi- The characterization and understanding of carbon flows in vores, which senesces and enters the detrital com- aquatic and terrestrial ecosystems are topics of paramount partment importance for several disciplines, such as ecology, bio- detritus. Dead primary producer material, which nor- geochemistry, oceanography, and climatology. Scientists mally becomes detached from the primary producer have been studying such flows in many diverse ecosystems after senescence for decades, and sufficient information is now available to herbivory. The amount (in g CÁmÀ2ÁyearÀ1) of net investigate whether any patterns are evident in how carbon primary production ingested or removed, including flows in ecosystems and to determine the factors respon- primary producer biomass discarded by herbivores sible for those patterns. In particular, a wealth of infor- net primary production. The amount (in g CÁmÀ2Á mation exists on the movement of carbon through the yearÀ1) of carbon assimilated through photosyn- activity of herbivores and consumers of detritus (i.e., de- thesis and not respired by the producer composers and detritivores), two of the major agents of nutrient concentration (producer or detritus).
    [Show full text]
  • Ecosystem Ecology
    Ecosystem Ecology • The biological and physical components of the environment are a single interactive system in the concept of the ecosystem – A.G. Tansley coined “ecosystem” in 1935 Ecosystem = Ecosystem = A group of interacting populations and their physical environment. All interacting by a flow of energy and with their physical and chemical environments. Ecosystems can be Large Small Ecosystem Ecology • An ecosystem is a spatial concept. It has boundaries and can be viewed in the context of its surrounding environment – It is sometimes difficult to clearly separate ecosystems Simple Energy input from Ecosystem sun Model Producers Autotrophs (plants and other self-feeding organisms) Nutrient Cycling Consumers Heterotrophs (animals, most fungi, many protists, many bacteria) Energy output (mainly metabolic heat) Ecosystem Materials Plants Animals Ecosystem Ecology • Community structure varies in response to environmental conditions • Organisms, in part, define the abiotic environment through succession – Tress affect temperature in a forest – Phytoplankton can affect water temperature Energy and Materials • Inputs are exchanges from the surrounding environment into the ecosystem • Outputs are exchanges from inside the ecosystem to the surrounding environment • A closed ecosystem is one with no inputs; an open ecosystem receives inputs form the surrounding environment Ecosystems 1. Population Interactions 2. Energy Flow 3. Material Cycles Ecosystems 1. Population Interactions 2. Energy Flow 3. Material Cycles Modes of Nutrition • Autotrophs – Capture sunlight or chemical energy – Primary producers • Heterotrophs – Extract energy from other organisms or organic wastes – Consumers, decomposers, detritivores Role of Organisms • Producers (photoautotrophs) Primary Producers Photoautotrophs + + + = + Sunlight + water + CO2 + minerals = C6H12O6 O2 sugar oxygen Energy Materials Concept 21.1 Feeding Relationships • Each feeding category, or trophic level, is based on the number of feeding steps by which it is separated from autotrophs.
    [Show full text]