Many common algae’s are controlled easily with algaecides, but resistant algae are those that are extremely difficult to control because they have protective mucilage which are completely covering the chloroplast, that resists penetration from chemicals.
Resistant algae may be one of two types: Lyngbya or pithophora. Lyngbya algae species form green, black or gray clumps made up of thousands of cells that may be found on the bottom of the pond or floating along the surface. Pithophora is a dark green filamentous algae often referred to as horsehair algae. It grows in coarse, tangled clumps of filaments that resemble steel wool. Because of tis high production of reproductive cells, pithophora algae grow prolifically on the bottom of ponds, and sometimes on the water’s surface.
Copper based algaecides, e.g., copper sulphate, has the following limitations:
Proposed Algaecides for Orana 5 Pond
Agmin Chelates Pty Ltd produces two APVMA registered algaecides, they are:
Kupramine is an EDA chelated copper complex having a high stability constant for the proton-ligand complex. This allows that the EDA-metal chelate is not negated by the:
Classification of Algae
For practical purposes a simple classification of algae species in relation to the required application of “Lethal Cu Concentration” is shown in Table 1, below. Although, the Agmin copper chelates complex is a total spectrum algaecide yet a variable quantity of copper is required for the different groups of algae species and for different algal densities.
Copper based algaecides, e.g., copper sulphate, has the following limitations:
- Copper (Cu) precipitates under alkaline conditions, formulations include ingredients such as organic acids or chelating agents to maintain Cu activity. These lead to a higher chemical cost and have their own safety concerns.
- Cu has a tendency to accumulate in mud and sediments.
- Cu is recognised for its toxicity to fish and invertebrates.
- High levels of Cu in aquatic plants can accumulate from a very low level in water, when exposed for long periods of time.
Proposed Algaecides for Orana 5 Pond
Agmin Chelates Pty Ltd produces two APVMA registered algaecides, they are:
- Cupricide: Used in Lakes, Potable Water Reservoirs, Rice Paddies, Irrigation Conveyance Systems, Canals, and Laterals.
- Kupramine: A strongly chelated formulation specifically designed algaecide for waste waters (containing high levels of Particulate matter – clay and humus colloids)
Kupramine is an EDA chelated copper complex having a high stability constant for the proton-ligand complex. This allows that the EDA-metal chelate is not negated by the:
- Adsorbing capacity of particulate matter for the weakly chelated metal-complexes.
- High concentration of DOM produce large quantities of ionically charged organic colloids (humus) thus eliminating the effectiveness of the algaecides which are not strongly complexed.
- Very hard water having pH levels above 9.5 destroys the weakly chelated proton-liquid complex and release the copper ions which easily precipitates the hydrous carbonate of copper.
Classification of Algae
For practical purposes a simple classification of algae species in relation to the required application of “Lethal Cu Concentration” is shown in Table 1, below. Although, the Agmin copper chelates complex is a total spectrum algaecide yet a variable quantity of copper is required for the different groups of algae species and for different algal densities.
Table 1. Lethal Cu Concentrations required for algae.
| Algae Species | Lethal Cu Concentration | ||
|---|---|---|---|
| Low Density | Medium Density | High Density | |
| 1. Planktonic algae (suspended colony forming) | 0.1 mg L-1 | 0.3 mg L-1 | 0.5 mg L-1 |
| 2. Filamentous algae (mat forming, thick walled) | 0.4 mg L-1 | 0.6 mg L-1 | 0.8 mg L-1 |
| 3. Chara & Nitella (Benthic attached to Benthos) | 0.5 mg L-1 | 0.8 mg L-1 | 1.1 mg L-1 |
Lyngbya
This is a species which is particularly troublesome to control using traditional copper sulphate and chelates. They grow in colonies forming small spongy masses of mucilage. These blue-green, black or gray clumps made up of thousands of individual cells will lie on the bottom or float to the surface.
Because of its protective mucilage, chemical control is difficult. Lyngbya is one of the groups of cyanobacteria that are of special concern. This long, hair-like organism is a filamentous alga that can form large benthic (on the bottom) and surface mats (blooms). Lyngbya normally grows in dense mats at the bottoms of nutrient enriched lakes and spring fed systems. These mats produce gasses during photosynthesis that often causes the mats to rise to the surface. At the surface, winds pile the algal mats against shorelines or in navigation channels; these mats can be several acres in size.
Lyngbya is one of the cyanobacteria that are known to release toxins into the water. These three toxins, debromoaplysiatoxin, aplysiatoxin and lyngbyatoxin have been found to be a major cause of dermatitis.
This is a species which is particularly troublesome to control using traditional copper sulphate and chelates. They grow in colonies forming small spongy masses of mucilage. These blue-green, black or gray clumps made up of thousands of individual cells will lie on the bottom or float to the surface.
Because of its protective mucilage, chemical control is difficult. Lyngbya is one of the groups of cyanobacteria that are of special concern. This long, hair-like organism is a filamentous alga that can form large benthic (on the bottom) and surface mats (blooms). Lyngbya normally grows in dense mats at the bottoms of nutrient enriched lakes and spring fed systems. These mats produce gasses during photosynthesis that often causes the mats to rise to the surface. At the surface, winds pile the algal mats against shorelines or in navigation channels; these mats can be several acres in size.
Lyngbya is one of the cyanobacteria that are known to release toxins into the water. These three toxins, debromoaplysiatoxin, aplysiatoxin and lyngbyatoxin have been found to be a major cause of dermatitis.