Modern Reef Keeping - Chemistry. Modern reef keeping. Optimal water parameters for reef keeping Life support Temperature Oxygen Salinity pH/ Alk Introduction to skeletogenesis Ca , Alk , Mg Typical syndromes in aquarium Secondary elements K, I , Sr , Fe
All biological processes occur in aqueous environment
Water temperature in the tropic’s range : 22 -30°C (NOAA,WOA98)
Water temp. rise in 2 degrees
Oxygen levels in coral reefs (ppm)
DO levels in coral reefs: 4.5-5 mg/l with 80% saturation (NOAA,WOA98)
Salinity levels in coral reefs (ppt)
salinity levels in coral reefs: 33-38 (ppt) (NOAA,WOA98)
Specific Gravity is the densities ratio
between salt water solution and the
same volume of pure water at 4°C
S.G. doesn’t have units, measured by
hydrometer and it is temp. dependent!!!
pH levels in coral reefs: 8.05-8.12
narrow range of pH.
from gills: 7.8-8.4 (marine fish).
CO2 + H2O <=> H2CO3 <=> H+ + HCO3- <=> 2H + + CO32-
In sea water: (1%) (93%) (6%)
The Zooxanthellae takes CO2 from coral respiration and from HCO3- and convert it to carbohydrates
In low concentration
The Carbohydrates are used as fuel for the active transporters
Coral skeleton = Aragonite
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.
High nutrient levels enhances
bacteria proliferation and algae
ppm< O₂< 0.2 ppm
0>ORP> -180 mv
12NO₃⁻ + 10CH₃OH+ 12H⁺-> 6N₂+10CO₂ +26H2O
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- Eutrophication
Fish food and extracts, Dead Bacteria and micro-algae, Coral tissues and mucus
Organic matter decomposition reduce dissolved oxygen
Oxidation – nitrification - NH₃ + O₂ -> NO₃⁻
Reduction –De nitrification - NO₃⁻ + C -> N₂
Increase bio - load
Damage to corals and fish
Toxins, competition with Zooxanthellae
God help us, it’s only the second lecture and we have another 3…