Red, Green and Brown: What's in the Water?

Each year people see things in streams, ponds and estuaries that cause concern, but this does not mean that the water is polluted. Often, there is a natural cause for these conditions.

If you are concerned about water quality because of something you have seen, contact the Department of Communities, Land and Environment at (902) 368-5044. If you suspect that a problem may need immediate attention (like a chemical or petroleum spill, or dead or dying fish/shellfish), contact Environmental Emergency toll-free at 1-800-565-1633.

Some of the strange, but natural, things in surface water include:

Foam

Foam can develop naturally in water. Decaying plants, leaves, and animals (organic matter) act much like soap. The organic matter allows the water to mix with air. This creates bubbles and foam in areas where the water is moving quickly, such as below waterfalls, or where waves break on the shore.

Foam in slow moving area below a culvert
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Foam in slow moving area below a culvert
                        
Photo of Foam on the Shoreline
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Foam on the Shoreline

 

Orange or Brown Slime

Orange/brown slime is caused by harmless bacteria that form slimy or fluffy deposits. These deposits ‘rust’ when iron (in the bacteria) and oxygen (in the air) come together. This slime is most commonly found near springs, where, iron-rich groundwater comes to the surface. Slimes can also form where there is an abundance of decaying plant or animal material.

Orange Slime in an Artesian Spring
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Orange Slime in an Artesian Spring
                        
Brown slime, with decaying algae, in a stream
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Brown slime, with decaying algae, in a stream

 

Green Coloured Water

Ponds and estuaries often turn green during the summer months. The colour, which can range from drab olive to ‘lime ricky’ green, is the result of a heavy growth (or bloom) of very small (microscopic) algae (known as phytoplankton). Blooms are often the result of nutrients in water and as a result are a concern to the environment.

A very bright turquoise green or blue–green colour to the water may indicate a bloom of blue–green algae (cyanobacteria). These blooms can also create a granular scum on the surface. If you suspect a blue–green algae bloom, report it to the PEI Department of Communities, Land and Environment (902) 368-5044. 

Olive-green algal bloom in a pond
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Olive-green algal bloom in a pond
                    
Lime-Ricky coloured algal bloom in a pond
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Lime-Ricky coloured algal bloom in a pond

 

Blue-green algal bloom
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Blue-green algal bloom
                    
Blue-green algal bloom showing granular appearance
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Blue-green algal bloom showing granular appearance

 

Green Moss or ‘Clouds’ 

Masses of filamentous algae (single algae cells that form long visible chains or filaments) can appear to form moss or clouds on the bottom of freshwater ponds. These algae masses are often slimy to the touch.

 

Green filamentous algae on the bottom of a pond
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Green filamentous algae on the bottom of a pond

 

Mats or Green Scum 

Mats or green scum are generally caused by a large growth (or bloom) of water plants or algae. Duckweed and filamentous algae are the most common causes in freshwater ponds. Sea lettuce forms mats in many Island estuaries.

Photo of Duckweed on a pond
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Duckweed on a pond
                    
Floating filamentous algae
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Floating filamentous algae

 

Photo of sea lettuce mat
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Sea lettuce mat

Red, Brown or Tea-coloured Water

Red, brown or tea-coloured (but otherwise clear) water is due to the presence of organic matter or plant pigments called tannins. The tannins actually ‘stain’ the water. Unlike the silt in muddy water, the tannin will not separate out if the water is left standing in a glass or bottle.

Photo of tannins in water
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Tannins in water

 

Milky White or Cloudy Green Coloured Water

Milky white or cloudy green coloured water in an estuary (the area where fresh and salt water mix) is generally a sign that an ‘anoxic event’ has occurred. These events happen when large amounts of algae or sea lettuce decompose. Decomposing plant material uses all, or most, of the oxygen in the water. Anoxic events result in a cloudy white to grey or green discolouration of the water as well as a rotten egg or rotten turnip type smell.

Photo of milky appearance of an anoxic event
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Milky appearance of an anoxic event
                          
Anoxic event with a cloudy grey-green appearance
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Anoxic event with a cloudy grey-green appearance

 

Report anoxic events to the PEI Department of Communities, Land and Environment (902) 368-5044.

Click here to see a list of estuaries with reported anoxic events since 2002.

Oily Sheen

One common cause of an oily ‘sheen’ on the surface of water is the presence of harmless iron- or manganese-loving bacteria. These bacteria are often found in waterlogged soils. Decaying plant and animal material can also create an oily appearance. Oily sheens caused by natural causes have no petroleum odour. Sheens caused by petroleum will also flow back together again when disturbed by poking with a stick. Natural sheens will stay separated.

 

Oily Sheen on the shoreline
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Oily Sheen on the shoreline

Yellow Scum/Slick

A pale yellow scum or slick is sometimes visible in Island waterways (including beaches) during the spring and early summer. Although it may look and behave like an oil slick, this scum is usually due to large amounts of tree pollen in the water. The pollen is slightly sticky, which makes it clump together. Because it is very light, it floats on the surface. Sometimes the scum will cover a large surface area of water. Islanders may notice that their cars and the surface of puddles are also covered with pollen. 

 

Pine pollen mixed with beach wrack near St. Peter's Harbour
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Pine pollen mixed with beach wrack near St. Peter's Harbour
    
Published date: 
August 23, 2015
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General Inquiries

Department of Communities, Land and Environment
4th Floor, Jones Building
11 Kent Street
PO Box 2000
Charlottetown, PE   C1A 7N8

Phone: 1-866-368-5044
Fax: (902) 368-5830

CLE@gov.pe.ca