하구및 연안생태Coastal management 2014 년 가을학기

Salt marsh productivity? Rate and factors affecting productivity of salt marsh Spartina alterniflora Remarkably high Important for estuarine food chains increase in spring flowers  dies dead biomass increase no live biomass in winter above 38 N decreasing trends of standing stock from gulf of Mexico to new England productivity: 200 ~ 6000 g dry wt/m2/yr Short term variation CO2 exchange method low in high tide : activity is low ? ; probably not

Below ground production difficult to distinguish “live” from “dead” almost always greater than above gound Method problem Tagging Follow both dead and live biomass

Factors affecting marsh production solar radiation temperature, tides, nutrient concentrations, soil types, drainage, oxygen concentration, pH

Factors affecting marsh production solar radiation temperature, evapotransportation Direct: solar energy Indirect: temperature  metabolic rates  evapotransportation change shows latitudinal gradient Wetland vegitation is not water limited and actual evapotransportation is almost same as PE (potential evapotransportation) : PE is closely related to temperature General relationship between productivity versus air temp. Low winter temp, ice formation

Tides Tidal subsidy !! positive relationship between tidal range and production gated marsh had low standing crop. can be a stress in very high range difference in stream side and inland marshes is greater in high tide.: complete drainage in stream side; dye experiment Percolation rates difference with the spartina

Nutrients Nitrogen addition increased the growth of S. alterniflora (not P) inland marshes had greater effects than stream side

Oxygen in sediment soil O2 conc. Is important for plant growth anoxic soil  H2S toxicity; inhibit respiration and nutrient uptake metaboilc pumping of O2 by marsh plant Fertilization increased Eh Interactions degree of anoxia is mild: malate (less toxic) accumulate: reused by spartina when aerobic condition reoccur alcoholic fermentation is not stimulated Anoxia severe : fermentation occur ethanol produced  lost of energy reduced growth

Salinity S. alterflora and Distichlis spicata: salt obligates S. patens : facultative halophyte S. alterflora : best in 10 ppt Can survie 30~40 ppt with aeration and N addition Osmotic stress (water loss) and cell membrane damage Membrane permeability change with salinity: nutrient uptake and water loss problem; increased permeability reduces ion selectivity Selectively concentrating preferred ions Salt removal via salt glands : salt deposit on the tips of S. alterflora. Low railfall: make high salinity and reduced nutrient delivery

PH, nature of soil S. alterflora : optimal at PH 6 Fine clay: higher nutrient level Soil density: high in stream side: input of mineral sediment during high tide New soil brings new nutrients

Age, herbivore age of a plant stand affects its productivity: as a marsh ages, there is increasing belowground biomass ; nutrient is tide up. Direct hervivory is low; les than 5% High productivity due to C4 plant; high light and temperature saturation level (30~35 versus 25 C) C3: phosphoglyceric acid C4: oxaloacetic acid - Less transpiring in C4 plants; less salt build up.

Mangrove productivity similar patterns are evident with salt marsh the highest among the forest ecosystem high productivity in riverine to low values in scrub forest Litterfall is strongly correlated with forest structure. Correlation with freshwater and nutrient, and decreased salt content

Mangrove productivity factors that control mangrove productivity: similar to salt marshes: no latitudinal gradient (occurs only at tropical zone) Flooding regime, lower salinity, higher nutrient level. Lower H2S level. Increased freshwater brings high nutrient and low salinity