Primary producers - Wikipedia Primary producers See also : Primary production The leaf is the primary site of photosynthesis in plants. Primary producers are organisms in an ecosystem that produce biomass from inorganic compounds ( autotrophs ). In almost all cases these are photosynthetically active organisms ( plants, cyanobacteria, protists and a number of other unicellular organisms ; see article on photosynthesis ). However, there are examples of archaea and bacteria ( unicellular organisms ) that produce biomass from the oxidation of inorganic chemical compounds ( chemoautotrophs ) in hydrothermal vents in the deep ocean. These organisms are considered to exist at the lowest trophic level. Fungi and other organisms that gain their biomass from oxidizing organic materials are called decomposers and are not primary producers. However, lichens located in tundra climates are an exceptional example of a primary producer that, by mutualistic symbiosis, combine photosynthesis by algae ( or additionally nitrogen fixation by cyanobacteria ) with the protection of a decomposer fungus. References Jump up ^ Post, David M. ( March 2002 ). `` USING STABLE ISOTOPES TO ESTIMATE TROPHIC POSITION : MODELS, METHODS, AND ASSUMPTIONS ''. Ecology. 83 ( 3 ) : 703 -- 718. doi : 10.1890 / 0012 - 9658 ( 2002 ) 083 ( 0703 : USITET ) 2.0.CO ; 2. External links `` Lichen Biology and the Environment ''. www.lichen.com. `` Lichens ''. herbarium.usu.edu. `` Lichens ''. archive.bio.ed.ac.uk. Ecology : Modelling ecosystems : Trophic components General Abiotic component Abiotic stress Behaviour Biogeochemical cycle Biomass Biotic component Biotic stress Carrying capacity Competition Ecosystem Ecosystem ecology Ecosystem model Keystone species List of feeding behaviours Metabolic theory of ecology Productivity Resource Producers Autotrophs Chemosynthesis Chemotrophs Foundation species Mixotrophs Myco - heterotrophy Mycotroph Organotrophs Photoheterotrophs Photosynthesis Photosynthetic efficiency Phototrophs Primary nutritional groups Primary production Consumers Apex predator Bacterivore Carnivores Chemoorganotroph Foraging Generalist and specialist species Intraguild predation Herbivores Heterotroph Heterotrophic nutrition Insectivore Mesopredators Mesopredator release hypothesis Omnivores Optimal foraging theory Predation Prey switching Decomposers Chemoorganoheterotrophy Decomposition Detritivores Detritus Microorganisms Archaea Bacteriophage Environmental microbiology Lithoautotroph Lithotrophy Microbial cooperation Microbial ecology Microbial food web Microbial intelligence Microbial loop Microbial mat Microbial metabolism Phage ecology Food webs Biomagnification Ecological efficiency Ecological pyramid Energy flow Food chain Trophic level Example webs Cold seeps Hydrothermal vents Intertidal Kelp forests Lakes North Pacific Subtropical Gyre Rivers San Francisco Estuary Soil Tide pool Processes Ascendency Bioaccumulation Cascade effect Climax community Competitive exclusion principle Consumer - resource systems Copiotrophs Dominance Ecological network Ecological succession Energy quality Energy Systems Language f - ratio Feed conversion ratio Feeding frenzy Mesotrophic soil Nutrient cycle Oligotroph Paradox of the plankton Trophic cascade Trophic mutualism Trophic state index Defense / counter Animal coloration Antipredator adaptations Camouflage Deimatic behaviour Herbivore adaptations to plant defense Mimicry Plant defense against herbivory Predator avoidance in schooling fish Ecology : Modelling ecosystems : Other components Population ecology Abundance Allee effect Depensation Ecological yield Effective population size Intraspecific competition Logistic function Malthusian growth model Maximum sustainable yield Overpopulation in wild animals Overexploitation Population cycle Population dynamics Population modeling Population size Predator -- prey ( Lotka -- Volterra ) equations Recruitment Resilience Small population size Stability Species Biodiversity Density - dependent inhibition Ecological effects of biodiversity Ecological extinction Endemic species Flagship species Gradient analysis Indicator species Introduced species Invasive species Latitudinal gradients in species diversity Minimum viable population Neutral theory Occupancy -- abundance relationship Population viability analysis Priority effect Rapoport 's rule Relative abundance distribution Relative species abundance Species diversity Species homogeneity Species richness Species distribution Species - area curve Umbrella species Species interaction Antibiosis Biological interaction Commensalism Community ecology Ecological facilitation Interspecific competition Mutualism Storage effect Spatial ecology Biogeography Cross-boundary subsidy Ecocline Ecotone Ecotype Disturbance Edge effects Foster 's rule Habitat fragmentation Ideal free distribution Intermediate Disturbance Hypothesis Island biogeography Landscape ecology Landscape epidemiology Landscape limnology Metapopulation Patch dynamics r / K selection theory Source -- sink dynamics Niche Ecological niche Ecological trap Ecosystem engineer Environmental niche modelling Guild Habitat Marine habitats Limiting similarity Niche apportionment models Niche construction Niche differentiation Other networks Assembly rules Bateman 's principle Bioluminescence Ecological collapse Ecological debt Ecological deficit Ecological energetics Ecological indicator Ecological threshold Ecosystem diversity Emergence Extinction debt Kleiber 's law Liebig 's law of the minimum Marginal value theorem Thorson 's rule Xerosere Other Allometry Alternative stable state Balance of nature Biological data visualization Constructal theory Ecocline Ecological economics Ecological footprint Ecological forecasting Ecological humanities Ecological stoichiometry Ecopath Ecosystem based fisheries Endolith Evolutionary ecology Functional ecology Industrial ecology Macroecology Microecosystem Natural environment Regime shift Systems ecology Urban ecology Theoretical ecology List of ecology topics This ecology - related article is a stub. 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Question: where would a primary producer be located in a food chain
Answer: the lowest trophic level