2 Modern reef keeping Optimal water parameters for reef keeping Life supportTemperatureOxygenSalinitypH/AlkIntroduction to skeletogenesisCa, Alk, MgTypical syndromes in aquariumSecondary elementsK, I, Sr, FeNutrients, Pollutants & AlgaePO4 / NO3 /SiO4SourcesTypical algae in reef tank
3 All biological processes occur in aqueous environment Life support parameters- Temperature, Salinity, Oxygen and pH/Alkalinity.All biological processes occur in aqueous environmentTemperatureSalinityDissolved GassespH
4 Life support parameters- Temperature Water temperature in the tropic’s range : °C (NOAA,WOA98)
5 Life support parameters- Temperature One of the most crucial water parameter in the reef environment with direct impact on:Dissolved gases and their saturationInhabitance’s metabolismAccuracy of S.G. and pH measurements.The Key is Stability - Temperature fluctuations of more than 2°C are the main reason for coral bleachingWater temp. rise in 2 degrees
6 Life support parameters- Temperature Recommended temp in a reef tank: 26-27°CCloser to natural temp. at most areas where corals are collected from.Increase metabolism= rapid growth and better immune response
7 Life support parameters- Oxygen Oxygen levels in coral reefs (ppm)DO levels in coral reefs: mg/l with 80% saturation (NOAA,WOA98)
8 Life support parameters- Oxygen Dissolved OxygenDO is temperature and salinity dependent.As long as the DO levels are in saturated/ slight below super-saturated , the reef inhabitance can tolerate higher temperature (28-29°C)Saturated oxygen levels prevent dissolved CO2 buildup and pH drops.
9 Life support parameters- Oxygen Dissolved OxygenIncreasing DO:Protein skimmerSurface skimmerWater surface agitationCan be measured with colorimetric test kit or non-directly but very efficient with RedOx meter.Super saturation =Micro-bubbles
10 Life support parameters- Salinity Salinity levels in coral reefs (ppt)salinity levels in coral reefs: (ppt) (NOAA,WOA98)
11 Life support parameters- Salinity Salinity is the summery of all the dissolved salts mass in volume of water and it is measured as ppt = g/L = ‰ =psu, with refractometers or Conductivity meters (mS).Specific Gravity is the densities ratiobetween salt water solution and thesame volume of pure water at 4°CS.G. doesn’t have units, measured byhydrometer and it is temp. dependent!!!Salinity affects marine organisms because the process of osmosis.Na & Cl concentration in the aqueous medium has direct influence on marine organisms metabolism – Coral calcification.Recommended salinity in reef tank: ppt for optimal calcification.
12 Life support parameters- pH. pH levels in coral reefs:
13 Life support parameters- pH/Alkalinity pH and dissolved CO2All biological processes occur in specificnarrow range of pH.Optimal Calcification pH: 8.3Optimal ammonia removalfrom gills: (marine fish).Optimal level for reef tank:pH levels major influential factor is CO2- alkalinityCO2 + H2O <=> H2CO3 <=> H+ + HCO3- <=> 2H + + CO32-In sea water: (1%) (93%) (6%)How to prevent pH drops:Stable alkalinity (buffer) meq/lProtein skimmingWater agitationOrganics removal
14 Introduction to Skeletogenesis or coral Calcification The site : Coral polypThe lead stars : Ca⁺², HCO₃⁻The co-stars: Mg ⁺², H ⁺, CO₂, Sr ⁺²The director: ZooxanthellaeSpecial effect: Light
15 Introduction to Skeletogenesis or coral Calcification Coral TissueSea WaterThe Zooxanthellae takes CO2 from coral respiration and from HCO3- and convert it to carbohydratesIn low concentrationMg ⁺HCO3-Ca⁺²Passive diffusionHCO3-The Carbohydrates are used as fuel for the active transportersg ⁺⁺²Active diffusionHCO3-Ca⁺²HCO3-Ca⁺²MgHCO3-Ca +2MgCoral skeleton = Aragonite
16 Introduction to Skeletogenesis or coral Calcification Balanced levels at pH =8.3 Salinity = 33 pptCa⁺² ppmAlkMg⁺² ppmFish3802.5-37-8.51150Soft4003-3.58.5-101200LPS4253.5-410-11SPS4554-4.51350SPS COLORS43038.51300Optimal conditions for skeletogenesis:Creating positives ionic gradient from the surrounded water to the inner coral layers.Balanced quantities of the building blocks.Proper pH and SalinityEnergy source
17 Introduction to Skeletogenesis or coral Calcification The Key = Balance?
18 Introduction to Skeletogenesis or coral Calcification The role of Magnesium:“The Buffer “ of the buffer = MgCO3-Controls precipitationControls CaCO3 crystallization = skeletal strengthImportant co-factor in zooxanthellae photosynthesis.Mg
19 Introduction to Skeletogenesis or coral Calcification- Typical Reef Syndromes: AreaExplanationReasonsSolution1High Alkalinity Low Calcium (usually low pH)Unbalanced salt mixesUnbalanced A+B supp.Ca reactor adjustmentSuccess calciumCaOH15% water change with CP salt.2Low Alkalinity Low Calcium (usually low pH)Low salinityLow magnesiumCP saltReef Gro KitCalkReducing lighting hours3Low Alkalinity High CalciumSuccess Coral Buff & MagnesiumStop CaOH if used4High Alkalinity High CalciumHigh salinityWrong additives calculationTimeIncrease lighting hours and currents to accelerate calcification.
20 The role of other important major, minor and trace elements: Many other elements are used as co-factors in many biological processes. The most important are those that must be replenished on regular basis.K⁺ - Zooxanthellae nutrient, promotes red/pink/ Purple pigments. Incorporate with active membrane transportation pumps (Na/K)Sr⁺² - Increase skeleton strength by controlling the formation of aragonite instead of calcite (Like magnesium)Fe⁺³/Mn⁻² - Important photosynthesis co-factor, Zooxanthellae nutrient, promotes Green pigments. Important co-factor in de-nitrification.I-- Important antioxidant , control Photosynthetic oxygen radicals in Soft and LPS corals. Promote pigments formation and reduce bleaching by UV shock.
21 Pollution and pollutants Coral reefs develop and flourish only in oligotrophic ocean areas with clear, unpolluted with limited nutrients in the water.In the natural reef environment, the major nutrients N, P, C are only available for the zooxanthellae (Coral symbiosis)Pollution – When the nutrients reach to a certain levels they stop being the limited factor in the reef system.High nutrient levels enhancesbacteria proliferation and algaebloom- Eutrophication.
23 Pollutants - N In natural corals reef: NO₃⁻. < 0.3ppm Nitrogen forms in the aquarium: NH₃/NH₄⁺, NO₃⁻.Sources: Organic mater decomposition, fish extracts, tap water, supp., salts, live rocks, coral sand.Negative effects of high nitrate levels:Indirect damage to corals by Increasing zooxanthellae densitiesCompetition with the coral on carbon source (HCO₃⁻)Intensive photosynthesis – high levels of oxygen radicals.ColorationEutrophication –nuisance algae outbreak.Treatments10-15% weekly water changeNO₃⁻ absorbers –zeolitesAssimilation - RefugiumEnhancing De – nitrification
24 Pollutants – N – De nitrification De – nitrification - Microbial process of nitrate reduction to nitrogen gas.Made by at least 10 facultative heterotrophic bacteria strains at anoxic levels – not anaerobic !ppm< O₂< 0.2 ppm0>ORP> -180 mv12NO₃⁻ + 10CH₃OH+ 12H⁺-> 6N₂+10CO₂ +26H2OCarbon source is the limited factor of the process (also Mo and Fe).Light inhibit de-nitrificationThe process occur naturally in live rocks pores and in the lower sediment (after 3 weeks from starting the cycle)Filtration methods to control/ enhance de-nitrification:De-nitratorsAssimilation - refugiumDSB/ Plenum
26 Pollutants - P Phosphate forms in marine environment : PO₄³⁻, HPO₃²⁻. Sources: Organic mater decomposition, fish extracts, tap water, supp., salts, live rocks, substrate.In corals reef: PO₄⁻. < 0.05 ppmNegative effects of high phosphate levels:Direct damage to corals by reducing available Ca ions for coral skeletogenesis. Ca3(PO4)2 formation inhibit CaCO₃ lattice formation.Increase zooxanthellae densities.Eutrophication – Cyanobacteria – Toxins.Treatments10-15% weekly water changePO₄³⁻ absorbers (FeO/OH, FeCl, AlO)Assimilation - RefugiumMicrobial reduction – carbon source.
27 Pollutants - SiSilicon forms in marine environment : Si(OH)4. Si(OH₃)o.Sources: tap water, supp., salts, live rocks, substrate.In corals reef: Si(OH)4 < 0.5 ppmImportant nutrient for sponges and snails.High level can cause diatoms outbreak for several days.Treatment:10-15% weekly water changeSi(OH)4 absorbers (FeO/OH, FeCl, AlO)Assimilation – Refugium with spongesDo nothing- it will leave as it comes.
28 Pollution- The magic circle of polluted tank. Pollution – When the nutrients reach to a certain levels they stop being the limited factor in the reef system. High nutrient levels enhances bacteria proliferation and algae bloom- EutrophicationOrganic matter:Fish food and extracts, Dead Bacteria and micro-algae, Coral tissues and mucusNO3Algae+ OxygenP04BacteriaOrganic matter decomposition reduce dissolved oxygen
29 Pollution- Oxygen demand and RedOx Many biological process can described as Reduction/Oxidation processes where electrons are transferred from one element to the other.Oxidation – nitrification - NH₃ + O₂ -> NO₃⁻Reduction –De nitrification - NO₃⁻ + C -> N₂All decomposition process requires oxygen as the oxidizer- therefore the oxygen levels will drop followed by a drop in RedOx level (mV).Increasing the oxygen levels, by removing the organic material out of the system, will increase the RedOx potential.How to increase RedOx in the reef aquarium:Good protein skimmer – takes the organics out and insert oxygen.Ozone- break down organics and oxidize water.
30 Pollution-Eutrophication of Nuisance algae Nuisance algae – undesired micro-algae or desired algae in un controlled growth (Macro algae).Micro-algae:Green hair algaeBlue-Green – CyanobacteriaDiatomsAll the three will appear naturally during the cycle period.Macro-algae:Caulerpa sp.The dangers of eutrophication :Competition on nutrients with zooxanthellae & coralline algaeCompetition on spaceCorals suffocation and shadingToxins – alleochemicalsOxygen reduction during the dark periodsOxygen super saturation during the light hours
31 Pollution-Eutrophication of Nuisance algae Nuisance algae – Green algaeMost common: Bryopsis, Debresia, Valonia.Circumstances for outbreak:Organics accumulationHigh nitrate, phosphate and iron levelsStrong lights not with the adequate PAR and color (to much red) or old bubbles.Damage:Competition on nutrients with zooxanthellae and coralline algaeCompetition on spaceCorals suffocation and shadingOxygen reduction during the dark periodsOxygen super saturation during the light hoursTreatments:Organics removal – Protein skimmerNutrient reduction - biological processesAssimilation – Macro-algae refuigiumPhysical trimmingFixing lights issues
32 Pollution-Eutrophication of Nuisance algae Nuisance algae – Blue green - CyanobacteriaOne of the oldest life forms.Circumstances for outbreak:Organics accumulationUnbalanced N : P ratio or high Phosphate – assimilate nitrogen from atmosphereDamage:ToxinsCompetition on spaceCorals suffocation and shadingOxygen reduction during the dark periodsTreatments:Organics removal – Protein skimmerPhosphate reduction - biological processes.Assimilation – Macro-algae refuigiumPhysical removal
33 Pollution-Eutrophication of Nuisance algae Nuisance algae – golden brown - DiatomsCircumstances for outbreak:SilicatesDamage:NothingTreatments:Patient !If it’s continues- check for Si in the fresh water source.
34 Pollution and pollutants-Summery OrganicsReduce oxygenIncrease bio - loadIncrease nutrientsSuffocationtoxinsCalcium accessibilityDamage to corals and fishAlgae outbreakSuffocation,Toxins, competition with Zooxanthellae
35 Thank you for listening!!! God help us, it’s only the second lecture and we have another 3…