Figure 1: Primary production, vertical flux and regeneration of nutrients in a coastal marine ecosystem. Also shown are some of the involved organisms such as phytoplankton, zooplankton, higher trophic levels and benthic organisms. The massive and narrow vertical arrows indicate scenarios of substantial and insignificant vertical flux.
Figure 2 :Direct relationship between dissolved inorganic N input and phytoplankton biomass, as mean annual chlorophyll a content
Figure 3: Conceptual figure, showing the various watershed and airshed anthropogenic nutrient sources, their input to estuarine and coastal waters via freshwater discharge, the establishment of hypoxia due to freshwater overlaying denser saltwater and the stimulation of primary production (eutrophication) and algal booms due to coastal nutrient enrichment. Note the linkage between nutrient enriched primary production and hypoxia as phytoplankton sink into stratified bottom water. Also, note potential negative impacts of hypoxia on bottom dwelling finfish and shellfish as well as submersed aquatic vegetation communities, all of which require oxic conditions.
Figure 4 : Examples of phytoplankton blooms resulting from excessive nutrient loading is estuarine and coastal waters.
Figure 4 (con.) : Examples of phytoplankton blooms resulting from excessive nutrient loading is estuarine and coastal waters.
Figure 5 : Impacts of excessive primary production
Figure 6 : Impacts of anthropogenically - enchanced nutrient loading on coastal biogeochemical, trophodynamics and water quality, Note the numerous potenially negative feedbacks which come into play in response to increased eutrophication (i.e. accelerating primary productiion)
ผลผลิตเบื้องต้นคืออะไร the synthesis of organic material from inorganic compounds, such as CO 2 and water simply the rate at which phosynthesis proceeds primary producers –phytoplankton –macroalgae : Cladophora sp., Enteromorpha sp. –aquatic plants : sea grass –mangroves
องค์ประกอบของผลผลิตเบื้องต้น Gross primary production(P g ) –rate of photosynthesis, not reduced for losses to excretion or to respiration in its various forms Net primary production(P n ) –gross primary production less losses to respiration by phytoplankton Net community production(P nc ) –net primary production less losses to respiration by heterotrophic microorganisms gramms or moles of carbon fixed per unit volume, or per unit area, of water per unit time –g-C m -2 yr -1
วิธีการหาผลผลิตเบื้องต้น Light-dependent change in dissolved oxygen –net production : accumulation of oxygen in a light bottle –respiration : consumption of oxygen in a dark bottle –gross primary production : net production – respiration Light-dependent change in dissolved inorganic carbon –like the light-dark oxygen method –precision less than bulk oxygen methods –required extra procedures, such as filtration
วิธีการหาผลผลิตเบื้องต้น ( ต่อ ) The 14 C method –most commonly measured –very sensitive and good precision The 13 C method –used 13 C tracer The 18 O method Chlorophyll a method –gross primary production