하구및 연안생태Coastal management 2014 년 가을학기

Phosphorus cycling residence time is very short in estuary immobilized by autotrophs and non-autotrophs more exchange water and anaerobic sediments sulfide  enhance solubilization of inorganic phosphate If the water is anoxic, P may enter the water and stimulating the photosynthesis

sulfur cycling similar to N cycling assimilatory S reduction  biomass incorporation Dissimilatory S reduction : Desulfovibrio : much of the anaerobic carbon and energy flow Anoxygenic photosynthesis by green and purple sulfur bacteria : energy from H2S and sun light ; tidal flat mats Chemoautotrophs : Thiobacillus, Beggiatoa

Metals in material cycling manganese, cobalt precipitation by microbes

Factors controlling microbial activities not well known Light temperature water availability, flow, sediment texture, redox potential, nutrients, toxic substance, competition, predation Light : indirectly determine oxygen availability Temperature: increase process rate Water flow and water availability: most important but not well known; source and residence time Degree of OM degradation: depend on residence time Exchange of nutrients between water column and sediments: tidal inundation and velocity of water Water activity: water available for growth by organisms: decrease with increased salinity and sorption to soils; evaporation decreases water activity for microbes Texture of substratum: sandy sediment dries faster: smaller microbes; more oxygen penetration

Chemical regulatory factors quantity and quality of nutrients regulate microbial activity Radio isotope measurements labile : amino acid, sugars; turn over in a matter of hours Refractory : cellulose and lignin : month or years : common it is not clear that which is more important high C/N ratio in OM ; may require inorganic N for bacterial growth SO4 is commonly not limiting but may limit in oligohaline estuaries

Biological regulatory factors production of toxic end products by microbes fatty acids, alcohol, sulfide Effect of man made toxic material on microbes? : pesticide effect of competition

Other component of ecosystem primary productivity : microbes are producers Make nutrients Compete with producers for inorganic nutrients “Secondary primary producers”: chemoautotrophs Secondary production Food source for micro, meio, macrofauna Animals lack cellulolytic lignolytic enzyme; microbes can “feces” too

Disease plant and animal population is regulated by pathogenity of micro organism Die off of American oyster : protozoan? Reduction of eelgrass ; fungus? Vibrio; human disease

Nutrient cycling microbes are main player

Organic detritus what is the source of OD? how it is utilized? What is it?; different in various researchers Meaning disintegrate or diminish “ dead particulate organic matter inhabited by decomposer micro-organism “ all types of biogenic material which represent a potential energy source” some one excluded bacteria “all carbon lost from each trophic level in a nonpredatory pathway”: egestion, excretion, secretion, “nonviolent” mortality, allocthonous carbon

Organic detritus DOM POM DOC POC TOC Seston : suspended matter : living + non-living Tripton : only non living Plankton : living

Detrial source Allochthonous Autochthonous Into sediments Via burial Below ground production Dissolved form : leaching upto 1 g /m2 Particulate form DOM; turn over; difficult to measure: mix of labile and refractory

Scirpus triqueter biomass change and nutrient storage