I often see very high pH values (often over 9) at Lake Renvick at Icelandic State Park (North Dakota, USA). Is there a correlation between algae growth and pH
Part 5, July 2, 2019 (Lake Renwick at Icelandic State Park) - https://youtu.be/U9MS7mYgOPg
Also this is another reference:
"Water Quality
Water of Beira Lake is polluted, from which it gets a bad odour and green colour. But contray to the canal system of Colombo, the lake contains water with a very alkaline pH value got by primary production and continuous bloom. In August it gets its maximum value, but becomes more neutral from top to bottom, pH value decreasing from 10 to 8. Lake water never gets acidic pH.[3]
Conductivity of the water retains fairly stable between 250 μS/cm and 300 μS/cm, with a slight increase from May to August.[3]
Full temperature ranges between 29.3 and 35.4 °C. Average temperature is 31 °C and August is the warmest month. The temperature decreases rapidly 2 or 3 °C, from the surface to 60-100 cm in-depth and remains stable after that.[3]
Dissolved Oxygen generally follows the same trend than temperature in August. Likewise the thermocline, an oxycline appears exclusively in August. Below 1 meter depth, DO is stable at 7 mg/l during May, June and July. Though it is decreased during August from 13 mg/l to 6 mg/l, shallow depth allows preserving a sufficient level of oxygen. But it would be more stressful during dry season.[3]
Salinity is very stable (around 0.12 g/l) over time and along the water column."
- https://en.wikipedia.org/wiki/Beira_Lake#Water_Quality
pH increases since microalgae, with photosynthesis, remove carbon dioxide from the water. At very alkaline pH inorganic carbon is mainly present as carbonate. Many cyanobacteria can still grow, in alkaline conditions, because they can utilize HCO3 as carbon source and they possess a CO2-concentrating mechanism.
Well,
Article Importance of Controlling pH-depended Dissolved Inorganic Ca...
Regards
This correlation of bloom density and increased pH is widely noticed in cyanophycean microalgae as in Spirulina sp
Carbohydrates and bicarbonates are some of the major contributors of high pH in natural water systems and can be converted to biomass through photosynthesis.
As Eleftherios outlined at the top, photosynthesis removes dissolved CO2 (carbonic acid) from the water, pushing pH upward. Increased pH is correlated to photosynthesis, but it is not specific to any particular algal species- you can't use pH to identify algal species or families. In natural waters, there is a carbonate (CO2--) bicarbonate (HCO3-) CO2 "buffering system". If the buffering capacity is low (low concentrations of bicarbonate and carbonate), pH can exhibit wide swings: pH increasing rapidly during daytime photosynthesis, and falling rapidly at night, when organisms respire CO2. If there's a significant amount of algae growth (I'm trying to avoid using value-judgement adjectives such as "good"- this depends on the lake's situation), photosynthesis can drive pH very strongly.
Yes there is, alglas proliferate more in a medium alkaline PH, ranging from 7.5 to 8.0. Each time this Ph increases, up to 8.0 they proliferate better under optimal conditions of insolation and nutrients in water.
I can recommend two papers on this topic:
Chen, C.Y., Durbin, E.G. (1994): Effects of pH on growth and carbon uptake of marine phytoplankton. Marine Ecology Progress Series 109: 83-94.
Dubinski, Z., Rotem, J. (1974): Relations between algal populations and the pH of their media. Oecologia 16: 53-60.
In algae blooming water, the pH may vary during day and night time. The difference may be around 2 (from 7+_ to 9+_) because of CO2 and oxygen content change in water.
Actually, pH rise & drop during the day and night respectively, depends on the alkalinity of water. Moderate alkalinity buffer the change and suppress it to jump to elevated levels. So, before algae, just consider to measure the alkalinity of your water.
Literature indicates the following:
“Photosynthesis, respiration and decomposition all contribute to pH fluctuations due to their influences on CO2 levels. The extremity of these changes depends on the alkalinity of the water, but there are noticeable diurnal (daily) variations.
This influence is more measurable in bodies of water with high rates of respiration and decomposition.
It is accepted that in a diurnal cycle, the lowest pH is expected at dawn because CO2 produced by decomposition and aerobic respiration has accumulated since the previous dusk.
The highest pH is expected during the daylight hours, because pH rises at the rate at which carbon dioxide is fixed by plants. “
So the alkalinity of the water body and the rate of respiration and photosynthesis can have major impacts on pH during the day (see attached Figure below).
High pH concentrations coincide with peak dissolved oxygen concentrations in mid-afternoon at the height of algal photosynthesis.
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