1. 하구및 연안생태Coastal management
2015 년 가을학기

2. Generalized Estuary; top view
River, barrier island
Environmental factor change; depth, physical energy level, water clarity, salinity, biota chemical concentration, oxidizing reducing conditions in sediments
Sandy beach;
little (visible) life;
Wave; provides oxygen and food, remove wastes
Oxidized
Tidal pass; reduced currents, reducing condition
Worm flat, mollusc beds; intertidal, subtidal with currents; filter feeders

3. Generalized Estuary; top view
Submerged marine meadows, seagrass;
light available.
Fine sediments,
trap sediments;
reduced sediments
Thalassia testudinum
Zostera Marina
Polyhaline: ppt
Mesohaline: 15 ppt
Oligohaline: 0-5 ppt

7. Generalized Estuary; top view
Intertidal wetlands
Salt marshes: 온대
Mangrove swamps: 열대
Turbid waters
Highly reducing
Very fine sediments
High growth rates
Deposit feeders

11. Generalized Estuary; cross section view
Vertical attributes: intertidal zone
Flooded and exposed
Salt marsh, mangrove wetlands, algal beds, sand or mud flat, reef or mud flat
Light gradient
Euphotic zone; photosyntheis
Aphotic zone
Oxidizing condition
Aerobic or oxic
Anaerobic or anoix ; reduced
Coarse sediments; high energy, oxidized
Fine sediments; calm water, reduced
Influenced by biota; burrow, rooted plants

12. Generalized Estuary; longitudinal sections
Fresh and sea water mixing
Gradual increase of salinity
Salinity increase with depth
Net outflow to the sea at the surface
Net inflow of salt water on the bottom.
Euphotic zone depth decrease toward fresh water
Most turbid water 1~5 ppt.; turbidity maximum
phytoplankton, zooplankton, fishes
Benthic animals; infauna, meiofauna
Diversity of benthic animal changes along the logitudinal transects

13. Typical Estuarine food web
Food chain, food web; E.P. Odum(1971)
Trophic dynamics of estuary; complex
Different primary producers; salt marsh plants, mangroves, submerged sea grasses, benthic algae
Not a “grazing food web”(consumed alive); detritus food web
Importance of bottom
Plants grow on the bottom
Flow of food and inorganic nutrients between water and bottom
Filter feeders and deposit feeders
Fish and birds ; bottom feeders
Variety of PP, grazing+detritus, bottom, complex, many generalist top feeders

14. Estuarine Energy flow
Important processes go on which are not visible !!!
If we want to know how estuaries work!
Sunlight interact with N during photosynthesis
P flowing out of sediment and being moved to surface
Organic detritus flowing out of a marsh
Energy flow diagram
Detrital grazing food web
Tidal currents; transporting detritus, moving phytoplankton to benthic animals
Input of nutrients and organic matter; river and recycling
Sunlight and inorganic nutrients;  

15. Estuarine habitat type
High diversity of habitat type
High diversity of physical habitats
Beaches, passes, intertidal, shallow subtidal
Deeper areas, deltas
Biota has fully exploited these different areas
Salt marsh, tide pool, algal flats, oyster
Also creates diverse habitat

16. Ecological characterization and classification
Physical environments
Degree of protection from oceanic forces
Freshwater input; dissolved + suspended materials
Water circulation patterns; river + tidal currents + geomorphology ; tide is most important
Depth; strong coupling between bottom and water column in shallow depth
Salinity gradient; sharpness and pattern
Rate of geomorphological changes
Degree of change rather than the absolute level is more important !!
Microclimates
Water movements
Chemical cycling
Physical structure

17. Functional classification of estuarine ecosystems
Odum and Copeland (1972); functional system based on an energetic analysis.
Status of ecosystem is a balance between “ordering energy” and “stresses”
Energy source
Mechanical energy of moving water; food, recycling. Saves energy for organisms
Sunlight; photosynthesis, thermal gradients
Organic and inorganic fuel
Stress energies; disordering energy
Energy diverted from system; dam-reduce the material inputs
Microscale random disordering; 2nd law of thermodynamics; problem for all living creature; high is estuary due to environmental variability
Forced losses within system; potential energy is lost before it is used; tide, fishing by human, wetland distruction.

18. Functional classification of estuarine ecosystems
Energy and adaptation in different ecosystems
Estuarine ecosystem:
Moderate stress energy and similar among different system
So, changing temperature and sun light regime with lattitude is important
Tropic : highest solar energy, thermal disordering to overcome
Artic: prominent seasonal change, seasonal programing
When stress energies become large, adaptation is similar (위도에 상관없이) : sedimimentary deltas, hypersaline lagoons, beaches

19. estuarine ecosystem in geological context
10,000~15,000 yr old.; since LGM
Cease to exist in the near geological future!!
Will fill up
Sea level change; number decrease when sea level is low
Species and types of biological communities are old.
They will move back and forth

20. High productivity ; classical view
하구 생산성이 높다는 의미는? 2가지 의미
하구에 서식하는 생물의 생산성이 높음
자체 생산하는 유기물이 소비량보다 크다  고차 소비자 (예를 들면 어류) 에게 전달될 잉여 유기물이 있다.
Three types of PP ; diverse OM source; organic debris
Tidal movement
Abundant nutrient supply; in situ or from river
Rapid regeneration and conservation of nutrients
Benthic regeneration + shallow well mixed water column
Georgia estuaries: among the most productive natural ecosystem; Schelske and Odum (1962)

21. High productivity ; classical view; is it true?
Georgia : salt marsh grass, phytoplankton, benthic algae
Other estuaries : submerged seagrass magrove swamps, macroalgae
Organic matter input from river.
Year round production (?); only in low latitude.
The role of detritus : chapter 7
Tidal action: most important
Tidal action +other physical energy(wind, wave, riverine current)
Produce very complex water movement
Supply of nutrient : within the system or from the river?
Rapid regeneration + conservation of nutrients; high coupling between water column and bottom.

22. Other hypotheses about estuary
Intertidal wetland;
produce OM for estuary
Nursery for the estuarine species
Many important reaction takes places; regulates estuarien chemistry
Organic detritus is exported from wetlands and serves a food for estuarine consumers
Supports rich fisheries; relationships between wetland and fisheries “ estuary-fish coupling”