하구및 연안생태Coastal management

Presentation on theme: "하구및 연안생태Coastal management"— Presentation transcript:

1 하구및 연안생태Coastal management
2016 년 가을학기

2 하구의 화학적 과정의 중요성 태양에너지  에너지로 충전된 유기물: photosynthesis or chemosynthesis  생물활동  dissipated into heat 생체에 중요한 화학성분들은 없어지지 않고 보존된다. “one organisms waste become another’s nutrients”

3 하구의 화학적과정 들 해수와 담수의 화학 성분들 주요 산화-환원 반응들 대사에 중요한 가스들; 산소와 이산화 탄소
하구의 화학적 과정을 결정하는 요인들 Source (담수 혹은 해수)로 부터 유입되는 물질의 종류와 양 화학 반응의 종류 체류시간 해수와 담수의 화학 성분들 주요 산화-환원 반응들 대사에 중요한 가스들; 산소와 이산화 탄소 생체에 중요한 영양염 순환

4 해수와 강물의 성분 중금속 : 강으로 부터 유입; 입자형태; Fe, Mn 용존 형태에서 입자형태로의 전환
강물의 성분: 매우 다양함 암석의 풍화에서 유래한 염성분 (Salts) 침전된 물질 (해수스프레이, 먼지) 바닷물의 성분: 비교적 일정함. major minor component 생물학적으로 중요한 성분들은 대체적으로 강으로 부터 유입됨 Silicon, iron, N, P 화학적으로 중요한 성분은 대체적으로 강으로 부터 유입됨 Sulfate, bicarbonate 중금속 : 강으로 부터 유입; 입자형태; Fe, Mn 용존 형태에서 입자형태로의 전환 흡착, 유출 Adsorption or desorption 엉겨붙음 (Coagulation) 응집 (flocculation) 침전 (precipitation) 생물체에 의한 흡수 (Biotic assimilation), 배출 (excretion_

5 하구의 염분 특성 염분 (salinity); 해수 1kg 중에 녹아있는 염분의 양. 일반 해수 35 ppt (part per thousand) Major elements Trace elements; dissolved gas, nutrients

6 해수와 담수의 주요 성분들

7 하구의 물질 유입 토사, 중금속, 폐기물, 생화학물질 Dissolved, colloidal, particulate
Suspended load versus bed load

8 흡착과 응집 전기 화학적, 물리화학적, 생물학적 작용 물질의 크기를 크게 하여, 퇴적시키는 효과
광물; 산화철, 산화망간, 탄산칼슘 유기물 표면 면상응집; flocculation Enmeshment: 공기방울이나 침전물에 걸림

9 용존 이온의 행동 진흙입자에 흡착하기 좋은 성분들: highly charged ions:PO43- 80~90% 가 하구내에 흡착됨 응집 Flocculation: 염분 0~5 ppt 범위에서 많이 일어남 진흙입자 (Clay) 음의 전기 (- charges)를 가져 서로 반발하여 담수에서는 안정적인 suspension을 이루고 있음. 해수와 만나면 : - charged  neutral ; van der Waals force 이 작용하여 서로 뭉치게 됨  응집 및 퇴적 이러한 기작으로 인해 여러가지 화학물질들이 하구에 잡히게됨 (This trapping + estuarine circulation)

10 용존 이온의 행동 반응물 생성을 측정Reactant approach 생성물 approach
염분에 따른 물질 농도를 측정함; see if it is conservative 해수와 담수 농도가 매우 다를 때 효과적임 Mixing diagram; NO3, Sio2 sink in summer; conservative in winter NH4 source in summer Mn; complex Basic assumptions Riverine end member is constant over the mixing time No tributaries Provide no insights into the removal mechanism 생성물 approach Measure flocculent material Fe, Mn,Al, P is removed by flocculation between 0-18 ppt Only explains one mechanism Only good for some dissolved materials

11 Conservative versus non-conservative
Source or sink 의 유무에 따라 Conservative: 강물 유입, 해수혼합, 확산 등 물리적 적용에 의해서만 농도가 변함. Non-conservative;변환, 제거 기작이 있을때; 흡착, 생물에 축적, 흡수, 생성; 생태 환경에 중요.

12 Conservative versus non-conservative

13 산화 환원 반응 입자성 유기물 (POM)은 퇴적물에 축적됨
하구먹이망을 위한 에너지의 근원 ; electron donor 호흡 Respiration: oxidation-reduction (redox) reactions; 화학적으로는 한 물질의 전자가 다른 물질로 이동하는 것 Energy flow in estuary is regulated by electron acceptor !!!: 고등 생물에게는 익숙치 않은 개념 ; 먹이?와 공기? Electron acceptors O2 ; exhausted in sediment SO42- ; dominant; sulfate reduction produce hydrogen sulfide

14 Solar constant - 태양 상수: 2 cal/cm2/min 지표면에 약 50 % 도달 생태계는 약 0.23 % 이용.

15 유기물 충전된 battery와 같다. 과자 1g에서 나오는 에너지 포도당 (C6H12O6) 의 산화 C6H12O6 + 6O2 ---> 6CO2 +6H2O 276 g g g 108g 1g g g g

16 과자 1 g 의 열량 C6H12O6 + 6O2 ---> 6CO2 +6H2O 276 g 192g 264g 108g
발열량: ( )-217=675 kcal 1g g g g 발열량: 675/276 = 2.44 kcal=2440 cal

17 먹이 사슬 (food chain) 부식자

18 1m 1m - 1 평방 미터당 - 태양 에너지 연간 3.8 x109 cal 유입
과자 얼마에 해당하나? 360 g 초식자 생산 ~36 g 육식자 생산 ~3.6 g 1m 1m

19 Aerobic respiration (호흡)
C6H12O6 + 6O CO2 + 6H2O E

20 외호흡과 내호흡 내호흡: 미토콘드리아 – 산소를 전자 수용체로 사용.

21 The Electron tower CO2/glocose 2H+/H2 CO2/methanol CO2/Acetate
Eh0 (volts) DG0 per 2 electrons 10 Kcal steps CO2/glocose -0.50 -0.40 -0.30 -0.20 -0.10 0.0 +0.10 +0.20 +0.30 +0.40 +0.50 +0.60 +0.70 +0.80 +0.90 2H+/H2 CO2/methanol CO2/Acetate SO42-/H2S Fumarate/succinate NO3- /NO2- NO3- /N2 Fe3+/Fe2+ O2/H2O

22 Heterotrophy (mainly in lake)
Aerobic respiration give the highest growth yield for the bacteria. O2 is very poor, only upper mm (millimeter) of sediment have. So the lower heterotrophic activity ( reaction) needn’t O2 become important, degrade these organic material to inorganic material.. Vertical position, laminated sequence mainly determined by chemical energy liberated. In fact, often overlaps for uneven sediment or infauna disturbance—bioturbation.. (mainly in lake)

23 Various heterotrophic pathway (relative proportion)
380m marine sediment, negligible manganese(Mn) oxidation

24 Overview of benthic diagenesis processes

25 퇴적물의 산화환원 상태 표층은 산화 저층은 환원 상태
Redox potential (Eh); degree of oxidations; high value means more oxidized No free electron!! Oxidation and reduction occurs at the same time

26 퇴적물에서 산화제의 수직 분화 Predictable sequence of respiratory chemical processes O2 ; 0 cm NO3 :0~4 cm SO42- ; CO2: RDL : redox discontinuity layer Competition between anaerobic processes Ability to get the OM or H2 Toxic end products; H2S

27 Half-Cell Reactions The half-cell reaction that releases electrons is referred to as an oxidation reaction. The half-cell reaction that consumes electrons is referred to as a reduction reaction. The reactant that gets reduced is called an oxidizing agent; in our example, this is Cu. The reactant that gets oxidized is called a reducing agent; in our example this is Zn.

28 Energetics of Redox Reactions
Reactions proceed spontaneously in the direction that minimizes the energy of the reaction system (reactants and products) The resulting state is referred to as chemical equilibrium. The further the energy of a reaction system is from that minimal level, the stronger is the chemical drive to undergo the reactions required to reach equilibrium.

29 Gibbs Free Energy total energy is referred to as the Gibbs free energy, G. The resulting free energy change, G, is a measure of how far the original reaction mixture was from equilibrium. J/mol, cal/ mol

30 Standard Cell Potentials

31 G and Ecell G = −nF(Ecell)
F, Faraday’s constant = kcal/(V · mol electrons transferred) n =mol electrons transferred. Ecell = V G = −(2 mol electrons transferred) kcal V mol electrons transferred (+1.10 V) = −50.7 kcal

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33 A comparison of the p◦, G◦, and E◦ scales

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35 Relative Redox Intensity
O2 reactions: proceed rapidly because they are mediated by enzymes produced by marine organisms. The greater the difference in p between the oxidizing and reducing agents, the greater the free energy yield of the resulting redox reaction.

36 aerobic oxidation

37 Reducing Agents in Seawater

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42 생물 대사에 중요한 가스들 O2. CO2, N2, CH4, H2S, NH3, N2O
Abundant gases: N2, O2, Ar Noble gases: Ar, Ne, He, Kr, Xe N2:Ar ration: indicator of denitrification and nitrogen fixation 가스의 용해도 : Busen coeficient: volume of the pure gas 1 atm pressure that can dissolve in a unit volume of water at standard temperature and pressure.

43 Metabolic gases 대기 바다를 통한 가스의 교환 가스 교환 상수: Saturation depicts
O2 flux is 2 times more than N2 Co2 flux is 70 time more than N2 가스 교환 상수: Kd: AD/Dz 0.1~2.5 mg O2 m-2 h-1 Lower value: shallow salt pond Higher value: windy conditions Saturation depicts

44 이산화 탄소 시스템 이산화 탄소 (CO2)는 물과 반응 !!!
“Chemical composition of the ocean is the result of a great acid-base titration !!!” 산성분은 지구 내부로 부터 분출됨. Substance that can donate proton 염기성분은 암석의 풍화로 부터 용출됨 Substance that can accept proton Carbonate system Equilibrium constant

45 The carbonate system Carbonic acid formation: Hydration-dehydration; carbonic anhydrase Ionization Dissociation Controlled by pH Dissociation constant; k1’, k2’ not k1, k2: calculated from concentration rather than the activity.

46 Calculating Carbon system
TCO2, CO2 can be measured. All other should be calculated Buffering reaction of sea water: resist to the pH change. In sediments, however, high NH4+, HS- can exceeds buffering capacity On geologic time scale, suspended clay mineral provide buffering actions

47 Alkalinity Alkalinity: degree to which water accept protons
[Bicarbonate, carbonate, borate OH- ] – [H+] Borates can be ignored in normal pH Carbonate alkalinity: bicarbonate + carbonate Conservative: TCO2 >> CO2 and CO32- variation

48 CaCO3 Calcite Aragonite Shells of benthic animals; mollusks etc..

49 산소와 이산화탄소가 생물에게 미치는 영향 대기중의 CO2 농도는 해양의 2% 정도에 불과 of
Water, rock, carbonate sediments, living, dead organisms is much more abundant Green house gas: CO2 increase 0.3 % per year Diel changes in pH and O2 can be used to indicate production and consumption Photosynthesis: increase of O2 and pH

50 산소와 이산화탄소가 생물에게 미치는 영향 AOU: apparent oxygen utilization
Long-term changes in oxygen versus conservative tracers of water masses such as salinity can be used to estimate consumptions.; does not apply to estuaries Dispersion, vertical diffusuion, air-water transfer, production, respiration

51 O2 budget for Chesapeake Bay
Biological processes account for 43~69% of observed input Anoxia formations

52 Warm Temperatures Warm spring and summer temperatures heat the water surface.

53 O2 Calm seas decrease oxygen exchange at the surface.

54 Nutrients Warm fresh water and nutrients are delivered by the Mississippi River and float on the denser saltwater.

55 A stratified layer is formed with lighter, fresher, warmer water at the surface and heavier, saltier, cooler water near the bottom limiting oxygen mixing throughout the water column. Lighter Fresher Warmer Water Stratified Layer No O2 mixing Heavier Saltier Cooler Water

56 At the surface, plankton blooms occur when excess nutrients are present

57 When plankton die, they sink and decompose
Dead plankton and fecal pellets sink to the bottom, which increases carbon accumulation in the sediments. As nutrients are used up, phytoplankton are consumed by zooplankton causing an explosion in zooplankton populations as well. As the dead plants and animals and their fecal pellets sink to the bottom, bacteria use the available oxygen in the water column to decompose organic matter.

58 When plankton die, they sink to the bottom and decompose.
During decomposition bacteria use up most or all of the available oxygen. Dead Plankton No O2 Decomposers

59 During decomposition, bacteria use up most or all of the oxygen causing the water column to become hypoxic or anoxic. As decomposition increases in the water column and at the bottom, the oxygen is eventually used up causing hypoxic and anoxic conditions.

60 Mobile animals become stressed and leave
Stationary animals become stressed and/or die With low DO a decrease in diversity of benthic fauna occurs. A decrease in diversity indicates a degrading environment. Eventually, without oxygen, the benthic population will become stressed and die. If DO is < 2 mg/l mobile animals leave the area and stationary animals like clams and worms die because there is not enough oxygen to sustain them. The water and the bottom will smell like rotten eggs under anoxic conditions because hydrogen sulfide is produced once oxygen is depleted.

61 When little or no oxygen is present:
Mobile animals leave. Stationary animals become stressed or die.

62 Warm Temperatures O2 Dead Plankton Fresh River Water Nutrients
         Nutrients O2 Plankton Bloom Lighter, Fresher, Warmer, Water Dead Plankton Stratified Layer No O2 Mixing Heavier, Saltier, Cooler, Water No O2 Decomposers

63 When oxygen is mixed throughout the water column during fronts, hurricanes and tropical storms, hypoxia is broken up. Without mixing, the Gulf suffers: — mortality of fish and their food base — high losses of benthic (bottom dwellers) plants and animals — reductions in the number of species — disruption of fish spawning, recruitment and migration.

64 일차생산에 중요한 영양염 일종의 비료 Fertilizer !
C,N,P,Si,S,K,Mg,Na,Ca,Fe,Mn,Zn,Cu,B,Mo,Co,V, vitamins, thiamin, cyanocobalamin, biotin 주요 영양염 N, P, Si Constantly changing; river flow, ocean exchange Organic  inorganic 생태계에서 영양염 순환이 에너지 흐름을 좌우 할 수 있음 !!!; 따라서 영양염 순환을 이해하는 것이 생태계 순환에 필수적임. Mid 1960s : measurement of spatial and temporal concentration. Last 20 years: development of isotope: rates !

65 영양염의 종류와 상태 산화 정도 고형, 액체, 가스 화학구조 질소가 가장 다양함 ;산화수 -3~+5
유기질소: highly reduced P: PO43- :+5; ortho, papa, meta Si: dissolved +4 (H4SiO2) detrital quartz, aluminosilicate clays, dissolved silicon

66 영양염의 일반적인 분포 계절적 변동 Mid summer PO4 peak: temperature regulated regenerations and redox condition NO3: winter maxima; external input via land run-off NH4: high in sewage input sites; balance between phytoplankton uptake and benthic regneration

67 질소 순환

68 Why Nitrogen ? a building block in the structures of nucleic and amino acids strongly biolimiting Shares with many elements a role in reduction-oxidation reactions in the marine environment Provide feedbacks in the crustal-ocean-atmosphere factory that affect climate and atmospheric O2 levels strongly impacted by anthropogenic activities global N cycle as one of the most profound changes we have yet induced on our planet.

69 N cycling Many oxidation states
Redox transformations between these oxidation states; mediated by organisms difficult to study; complex, spatial and temporal variability global fluxes and reservoir sizes is still highly uncertain.

70 Nitrogen species N2(g): unreactive (triple bond between N atoms)
-“fixed” or reactive nitrogen (Nr). DIN (dissolved inorganic nitrogen): NO−3, NO−2 , and NH+4 DON : urea, amino acids, humic substances, nucleic acids (DNA and RNA), and the alkyl and quaternary amines.

71 Nitrogen species

72 N2 fixation Conversion of N2 gas into inorganic N (fixed N, reactive N) Natural microbial processes by 20th century, human production of reactive nitrogen via N2 fixation exceeded natural production rates. ~ 40% of the world’s population is fed by crops sustained by the anthropogenic formation of reactive nitrogen. reactive nitrogen is now accumulating in the atmosphere and hydrosphere with deleterious consequences including eutrophication, hypoxia, harmful algal blooms, smog, acid rain, and loss of stratospheric ozone, all of which lead to habitat degradation and loss of species diversity.

73 Nitrogen fixation N-cycling; complex Fixation: structural synthesis
Energy reaction: use NH4 for fuel : electron doner Oxidizing agent: use NO3 for electron acceptor N2: 78 % of air N-fixation N2 ammonium : by bacteria and blue-green algea Require large energy: 147 kcal/mole No O2 condition for nitrogenase : heterocysts of blue-green algae Trichodesmium: don’t have heterocysts; separate O2 from nitrogenase

74 Recent developments of N cycle
in couple of decades !!!

75 Nitrogen fixation Measurement
Acetylene reduction technique: substitute substrate or nitrogenase; acetylene  ethylene 15N-labelled N2 MIMS (An, 2001) Lake, freshwater : 30~80 % from N-fixation Natural N-fixation was enhanced by P addition to lake Inhibited by high NH4 condition N-fixation is relatively unimportant in estuaries Tropical seagrass bed: Epiphytic blue-green and sediments Why? Not known well: high NH4? : high sulfate inhibit molybdenum (chemically similar) accumulation for nitrogenase synthesis

76 Nitrification and denitrification
NH4 NO3; aerobic Autotrophs; NH4 for energy 1st step: nitrosomonas: 66 kcal /m 2nd step: nitrobactor: 17.5 kcal /m ; slower O2 availability is important ; 2 Ks for Nh4 : 25~750 uM; typical 150 uM Measurement : increase of NH4 or decrease of NO3 or CO2 in the presence of N-serve Increase of 15NO3 after 15NH4 addition NH4 < 5 uM inhibit nitrification Typical sediments: 50 ug atom m-2h-1; NH4 production is about 100ug atom m-2h-1 High in seagrass bed due to O2 production via root Two seasonal pattern; high in winter and fall; O2 availability

77 denitrification Use NO3 as electron acceptor to oxidize organic matter
Numerous bacteria; Pseudomonas denitrificans Facultative anaerobes N2O production: important for green house gas, break down of ozone Measurements N2 production rates N2O production in the presence of acetyene

78 Global denitrification budget

79 denitrification NO3 limits denitrification Ks for NO3: 10~50 uM
NO3 sources Land runoff + nitrification in the water ; large flux into the sediment can be observed Nitrification in oxic sediments  move to RDL or anoxic micro sites 50~100 ug-atom m-2h-1 10 fold OM loading  5 fold denitrification increase Explains low N/P ratio

80 하구 먹이망의 특징

81 전형적인 하구 먹이망 Food chain, food web; E.P. Odum(1971)
하구의 섭식 동력학 (Trophic dynamics) 일차 생산자가 다양 : 염생식물, 해조류 해초류, mangroves, submerged sea grasses, 저서 미세 조류(benthic algae) Not a “grazing food web”(consumed alive); detritus food web 퇴적물 바닥의 중요성 Plants grow on the bottom; 바닥이 유광층 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

82 하구의 에너지 흐름 Energy flow diagram 중요한 과정은 보이지 않는 곳에서 이루어 짐 !!!
If we want to know how estuaries work! 태양 에너지는 질소순환과 상호작용을 일으킴 인 (P) 성분은 퇴적물로 부터 나와 유광층으로 유입됨 염습지로 부터 유기물이 유출됨 (outwelling theory) Energy flow diagram 부식질 먹이망 Detrital grazing food web 조석의 중요성 Tidal currents; transporting detritus, moving phytoplankton to benthic animals 강을 통한 영양염 공급과 재생산 Sunlight and inorganic nutrients;  

83 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

84 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: 모든 계절 동안 태양에너지가 낭비되지 않고 이용될 수 있다. 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)

85 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.

86 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”