?
This tells us how difficult it is to build calcium-carbonate shells/skeletons
Aragonite Saturation
The water has a phosphate level of 0.05 mg/L and a nitrate level of 3 mg/L. What’s wrong?
Nitrate levels are too high (it’s normally <1 mg/L)
Complete the chain: More nutrients → bigger algal blooms → more dead algae sink → ______ → lower bottom dissolved oxygen (DO)
Higher Biochemical Oxygen Demand (as bacteria decompose the dead algae)
A reef has an aragonite saturation of Ω = 0.8. How are the shells doing?
The shells are actively dissolving
What is the normal tropical reef aragonite saturation?
>3–4
Phosphate is at 0.05 mg/L, nitrate at 0.5 mg/L, fecal coliform at 250 CFU/100 mL, and aragonite saturation at Ω 3.5. What, if anything, is wrong?
The fecal coliform count is too high above <5–14, indicating contamination
The indicator species which shows that sewage or animal waste may be present
Fecal Coliform
Healthy estuary phosphate is about what range?
0.01–0.1 mg/L
Fertilizer washes into an estuary, causing phosphate levels to rise above 0.1 mg/L. What problem could develop?
An algal bloom
Does clear healthy reef water have high, medium, or low phosphate and nitrate levels?
Very low nutrient levels
What nitrate concentration is normal for an estuary?
<1 mg/L
The fecal coliform levels spiked after heavy rain. Why?
The water washed animal/human waste from the land to the sea
Nutrients and Fecal Coliform wash into a river through runoff. What is the area of land that drains this water into the river called?
A watershed
Phosphate = 0.8 mg/L, Nitrate = 0.8 mg/L, and Ω = 3.5. What, if anything, is wrong?
Phosphate levels are elevated above 0.01–0.1 mg/L
Below what aragonite saturation level (Ω) does aragonite begin to dissolve?
Below Ω 1
There are much more shells present in an area than before. What happened to aragonite saturation?
Ω increased
How do you commonly measure phosphate and nitrate concentrations?
Colorimetric tests (color changes where a darker color indicates a higher concentration)
The water has phosphate at 0.05 mg/L, nitrate at 0.5 mg/L, fecal coliform at 10 CFU/100 mL, and aragonite saturation at Ω 3.5. What, if anything, is wrong?
No problems here! All four are within their healthy ranges
The nutrient that becomes limiting in estuaries
Phosphates
pH 7.85, salinity 35, turbidity 2 NTU, DO 6.8 mg/L, Ω 1.1. What is the problem, if any?
Aragonite saturation is too low (correct is >3–4)
How do you measure total dissolved solids?
Evaporate the liquid and weigh what’s left
What are the units for Fecal Coliform?
CFU/100mL
You add salt to some water. What increases: TDS or TSS?
TDS (Total Dissolved Solids)
Examples of this include ammonia and Urea
Nitrates
Clean estuary fecal coliform is often in what range?
5–14 CFU/100 mL