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Coastal Oceanography (Fach) / Cravo-Summary (Lektion)

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• Oceanography and coastal oceanography introduction What Why Oceanography is interdisciplinary (geology, biology, chemistry, physic) important because half population live within 100km of coast Chemical reactions occure during mixing physical bc coastal areas are boundary layers b/w coast and open ocean = active exchange of kinetic energy and material transport can be quantified
• Significance Estuaries >major wildlife habitat = chem. components influence biolog processes and productivity >impacted greatly by runoff from rifers/sewage... >Interface river/sea > Transition Zone ! >Riverine pollutants act with seawater and accumulate in sediment >estuarine processes can alter fluxes of riverine material  >important to model and monitor water quality in estuaries
• chemical processes in an Estuary >changes in ionic strength (measure of conc. of ions in a solution), pH, colloid flocculation
• chemical compounds in a) River b) seawater a) Fe, Al, P, N, Si, DOC b) Cl, Na, Mg, SO4, Ca, K
• Changes in chemical composition due to a) Conservative mixing b) Chemic. processes within ocean and within estuaries c) Export compounds into sediment or from sediment into water
• Basic properties/processes Estuary a) Significant dilution of sea water with freshwater b) changes related to gradient of components (salinity, topography, circulation...) c)strong gradient of ionic strength (river salt 150mg/L, Ocean salt 35g/L) d)interaction water and SS e)Strong gradient chemical compounds with high suspendend particulate matter f) complex bc shallow depth (resusp. of sediments, high biol. activity)  g) temporal variable
• composition of ions comparing sea and river Ions very variable in river depending on geology, weahtering processes etc. Ions more or less constant in ocean >>Ion composition becomes like ocean t salinity 10 and then pretty constant and major and minor components change lots eg Cl- low in river but highest in seawater
• pH a)seawater b) river c) rain Sea: >7.8 River variable: 7.3 - 8.4 (acidic to alkaline streams) Rain:5.7 bc contain many gases
• SPM in Estuary influenced by >SPM settling, resuspension, biol. production >time scale (diurnal, tidal, spring/neap, seasonal..) >sedimentation of SPM from river and from shelf >dissolve material can change in conc. by interaction onto (adsorbtion)or into (absorption) particles or release (desorption) eg by adding salinity, mixing, incorporation into org. Material during decomposition/biol. production            > material flux from estuary not the same as river
• Natural waters a) Surface waters: River, streams , lakes, reservoirs b) marine waters: ocean and coastal waters c) estuaries: mixed water from fresh and salt 
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• Comparisson waters in composition and compounds behavior a)seawater b)Rainwater c) River water Rain water composition like seawater bc evaporates from there > conservative major compounds: Cl-, Na+, SO4 2-, K+ ...(99%) >Non conservative: Gases, nutrients, trace metals, DOM, Colloids, POM  a) TDS -Total dissolved salt = 35g/L >>300x more salt than river! >>5000x more than rain >source of salt is rock erosion and recycled from atmosphere (Cl- not rock but volcanic) b) TDS 7.1mg/L (diluted version of sea water) >aersosols carry marine salts to atmosphere and nucleus for condensation for clouds >composition like sea but when enter river, gains substantial ions >acidic:react with basin minerals c) TDS 120-150mg/L >Enriched in Calcium and Bicarbonate due to rock weathering  >Bicarbonate is similar in sea and river >Ions vary a lot from river to river depending on geology
• Marcet Principal No matter how salinity change the ratio of the major Ions (as defined before) stays more or less constant
• Suspended Solids in Estuary, River Sea >in River 400-500mg/L SS >at Sea surface >1mg/L >at estuary: 10-1000mg/L (highly variable) >more SS than disolved material >2x 10^10 tons of SS/year reach sea >only 5% of erided material reaches the estuary 
• Colloids definition Colloidal phases Colloids properties Classification =very small particles remaining susppended in aqueous solution (0.001-1mm)    >passing filters for Dissolved matter (0.45µm) >high amount of chemical flux is in colloidal form >phases: Clay Minerals, Iron (hydr)oxides, Humic/fulvic acids >Properties: high surface, high interfacial energy (kept in suspension), toxib substances more availbable to organisms >classification: Hydrophilic,hydrophob, association (both )
• Calssification collloids details a) hydrophillic : when touch water form colloids bc affirmation to water and supsension not highly affected when salts added b) hydrophobic: less interaction with water bc more stable  and particles repell each other bc chardged surface is surrounded by counter ions when salt is added they settle from auspension (eg clay particles) c) association: lipid molecules arrange in spherical from (hydrophillic hhead and hydrophob body) = micelles
• Chemical Gradient a) conservative b) non conservative c) TDL a) >linear relation b/w magnitude of mixing of end members and concentration >no change between dissolved and particulate  b) elements added or substracted greater than simple mixing (deviation from TDL) c) >>normal use salnity or chlorine as conservative mixing reference and then classify component via theoretical dilution line (TDL)    >>only work for dissolved materials     >>dilution line is negative for nutrients bc highest nutrients in river (low salinity)        >>silicate most conservative bc only used by one PP (diatoms) and is not affected by          anthropogenic effluents
• TDL a) addition b) removal a) abiotiical factors: desorption anions with increasing pH, replaced srobed cations on colloids by major cations, complexation by chlride or bicarbonate, human activities b) Abiotical: Increased sorption of cations with increasing pH, flocculation of colloid particles    Biotical: Phytoplankton consumption                             
• how are solutes affected 1. Phytosynthesis 2.. Adsorption and desorption 3. Coagulation 4: Settling 5: Reaction with sediment - exchange
• dissolved amount of elements depeneds on a) Load  b) activity coefficient c) ionic strength d)pH e) complexation trend  f)redoxpotential 
• a) solubulity product Ksp of solids b) Solubility of gases a) Conc. > Ksp (precipitation) Conc- < Ksp = solubilization  b) in intersticial waters of sediments   and depend on henry law
• colloidal properties of clay = most important colloidal matter in water >consist most of slicon  oxides and aluminium oxides, manganese oxide (weatherin and erosion) in layered structure >may attain net neg. charge due to metals with leess charge replacing al an sil  >PROBLEM: high sruface so sorb chem species and transport them thru system   But can also immobilize chem species purify 
• Aggregation of Particles Coagulation: reduce electrostatic repulsion  Flocculatuin forms bridging compounds between colloids normally colloids dont aggregate bc repulsion of double layer buut hydrophobic aggregate when salt is added >>when fresh water with high sediment enters salt water lead to lots of aggregagtion
• Soil colloids plate like shaped and <2µm  adsorb ions with opposite charge and water molecules and adsorbed ions then  interact with plant roots > provision of essential minerals eg adsorb ca, k, .... neg charge bec substitution of cations with lower charge  Cu is almost never free and chelated with org colloids 
• chemical characteristics of estuarine sediments >material transport can be instable due to salnity >modification SS colloids by coagulation, breakdown, flocculation.... >clay charge is neg. in freshwater but decrease with ionic strength up to pos. when sal 5-6 >interaction dissolved and particulate material: precipitation of dissolved, consumption dissolved, released particulate into solution by desorption, dissolution, biol. respiration....
• Oxidation reduction Redox oxidation is loss of electrons reduction is gain of electrons Redox:onne species undergoing oxidation another reduction
• Redox reaction water/sediment with increasing depth O2 used for respiration and decomposition of organic matter and oxidation of nitrogen to nitrite nitrate  When depleted Reduction of Nitrate (NO3- to NO2-) When depleted redunction of MnO2 and result Mn2+ when depleted reduction of FeO2 and result Fe2+ when depleted reduction of SO4O2- and result suplhide ions or hydrogen sulphide some reactions go up to formation of methan : methylen CH2 formation to CH4
• Problems with dams inhibit recharge of sediments > resulting in erosion of river bed below the dam accumulation of chemicals along bottom of the dam > when opend high increase in chemicals dry out strems, loss of habitat and biodiversity bring in invasive species (snails....) > bad for local species inhibit influx of nutrients > loss of species thus biodiversity inhibit migation for some species that go upstream for eg nesting... free flowing river transform into slack water reservoir > less circulation =more prone to eutrophication  change in physical and chem. properties (tem, sal, chem. conc and composition, circulation, DO >not suitable for local species) Lead to overall species shift
• organic processes in estuaries and how to quantify organic matter org. vs inorganic =organism mediate production and reduction of organic matter thru >respiration >primary production >Remineralization  >>influence =O2, CO2, change pH, Eh and chemical speciation quantify via filter  for dissolved and particulate fractions  normaly org. matter < inorg. matter
• POM and DOM relation DOM >> POM in estuary: DOM < 5mg/L-20mg/L and POM 0.5-5mg/L Vary strongly from adjacent environment
• Metals Metals normal to certain extent in sediments, depending on the types of rocks dominating  increase due to anthropogenic influences  have high affection to adsorb on particulated matter > thus sediment reflects degree of pollution  most common: Pb, Cu, Co, Ni, As, Cr, Hg
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• input sewage a)increase b)decrease a) BOD, SS, nutrients, metal, biol. production b) DO, 
• Redfield Ratio copmosition marine phytoplankton > 106 Mol C:16N:1P normally Nitrogen is limiting element (highest need is in nitrogen) but in fresh water it is phosphor bc adsorbs to sediments When sal increase or temp increase P desorbs from sediment and is not limiting anymore 
• a) remineralization b)nitrification c) denitrification a) = aerobic bacteria transform organic matter into inorganic (ammonium) b) Oxidize (add oxygen) to ammonium and formation of nitrate and nitrite c) take away the oxygen from nitrite and nitrite bc oxygen is depleted
• Ratio N:P Season in winter P is limiting element (ratio N:P higher than 16:1) in summer N is limiting (ratio lower 16:1) because a) less rain so no replenishment N                                                                          b) desorption of P from sediment due to higher temp
• oxygen and ammonium when organic matter is decomposed oxygen is used and ammonium produceed #= linear relation!
• Stressors of global change -Warming -Acidification -Anoxia -Eutrophication -Pollution
• results of global change Lead to more extreme events (floods, droughts..) impact ecology affect strongly coastal areas >>need monitoring and modeling 
• Basics CO2 and seasonal behavior 24% of CO2 in air go into ocean 416ppm CO2 in air in aprila 2020 2ppm/year increase problem is not increase but how fast in increases season: higher before summer bc more prooduction than reduction, lower in september bc reduction thru phytoplankton
• CO2 and relation organic matter CO2 lead to more respiration of phtoplankton and thus more respiration of consumers = mroe organic matter
• classification hypoxia and anoxia hypoxia 2mg/L Anoxia 20µm/L
• how do anoxid/hypoxic zones form and where are they upwelling anthropogenic influence enclosed water == low circulation so no distribution of oxygen with lower layers due to stratification (high temp) or due to enclosed area (trapped) ==increase in nutrient supply >high organic matter needs aerob decomposition > when decomposed layers below again normal O2 levels normally they are between 200-1000m (open ocean) or closer to surface when shallower
• OMZ lead to changes in =loss of fxed nitrogen =increase of hydrogen sulfide = production of climate active trace gases
• where (geography) have OMZ Baltic sea, northwest pacific, gulf of mexico
• ocean acidification increase of CO2 in atmosphere leads to increase of CO2 CO2 reacts with water and form carbonic acid which breaks into hydrogen ions and bicarbonate  »»carbonate ions (used for building skeletons) react with hydrogen ions and are not available for organisms »»decrease the pH which leads do dissolving the shells
• sea level rise =increase temp lead to thermal expansion =melting of glaciers and ice caps =loss of ice in greenland and antarctic ice sheets =rises 3.1mm/year

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