Cylindro (Cylindrospermopsis raciborskii)

Synonyms: Raphidiopsis raciborskii, Anabaena raciborskii

Description:

Cylindro (Cylindrospermopsis raciborskii, now also classified as Raphidiopsis raciborskii) is a microscopic blue-green alga ? really a type of bacteria called a cyanobacterium ? that originally came from warm tropical fresh waters [1][2]. It has spread to lakes and reservoirs around the world, including the Great Lakes region, where it likely arrived through shipping, boats, or migrating birds [1][2]. MISIN tracks it because some strains release toxins that can foul drinking water and harm people, pets, and wildlife when the alga multiplies into a bloom [1][3].

Identification:

Cylindro is far too small to see with the naked eye ? a single strand is a fraction of the width of a human hair, and naming this exact species takes a microscope or a lab test [1]. What you can see is a bloom: when the alga multiplies, it can tint the water a cloudy green, blue-green, or olive color [2][3]. Unlike some blue-green algae, Cylindro often does not form a thick surface scum, so the water tends to look discolored or murky throughout rather than coated on top [2]. Blooms are most likely in late summer and early fall, when the water is warm, calm, and rich in nutrients [2][4].

Under a microscope, Cylindro shows up as straight or slightly curved threads (called trichomes) with two kinds of special cells: thicker cells at the tips that pull nitrogen from the air, and tough resting cells that survive winter in the mud [1][2].

At-a-glance cues:

1. Water turns cloudy green, blue-green, or olive during warm, calm weather in late summer or fall [2][3]
2. The discoloration runs through the water rather than forming only a thick surface scum [2]
3. The alga itself cannot be seen or named without a microscope or lab test [1]
4. Most often appears in warm, slow-moving or standing nutrient-rich lakes, ponds, and reservoirs [2][4]

Habitat:

Cylindro lives in still or slow-moving fresh water ? lakes, ponds, reservoirs, and quiet stretches of river [1][2]. It is native to warm tropical and subtropical regions but has spread into temperate areas worldwide, including inland lakes near the Great Lakes [1][2]. It thrives in warm water, growing best between about 77 and 86 ?F (25?30 ?C), and favors calm water that settles into warm and cool layers [1][2]. It is unusually good at gathering scarce nutrients ? it can pull nitrogen from the air and store phosphorus ? so it can bloom even where other algae run short [2]. In the Great Lakes region it is so far present at low levels, but it is established and can increase where conditions suit it [1].

Reproduction:

Cylindro spreads from one water body to another in ways a homeowner may not expect. Its tough resting cells and live strands hitch rides on boats, trailers, fishing gear, and bait buckets, and they also travel on the feet and feathers of waterfowl moving between lakes [1][2]. Currents and floods carry it downstream, and it was likely first brought to the Great Lakes in ships' ballast water [1]. The alga multiplies by simply splitting its cells, so a small starting population can build into a bloom quickly when the water is warm and nutrient-rich [2]. Its resting cells sink into the sediment and survive cold winters, then sprout the next spring as the water warms to about 72?75 ?F (22?24 ?C), giving it a head start on native algae [1][2]. To slow its spread, clean, drain, and dry boats and gear before moving between waters [1].

Impact and Damage:

The biggest concern with Cylindro is health. Some strains make a toxin called cylindrospermopsin, and others make nerve toxins, that can build up in the water during a bloom [1][2]. In people, swallowing or swimming in toxic bloom water can cause fever, headache, vomiting, and bloody diarrhea, and the toxin can damage the liver and kidneys [1][3]. In one severe case, 141 people were hospitalized after a bloom contaminated a drinking-water supply [1]. Skin contact during recreation can also cause rashes and irritation [3]. Pets, livestock, and wildlife that drink or swim in bloom water can be poisoned as well [1][3].

For people on or near the water, a bloom can make a lake unsafe for swimming, boating, and fishing, and it can taint drinking-water supplies drawn from the lake, raising the cost of treating that water [1][3]. In natural areas, dense blooms cloud the water and block sunlight, and when the bloom dies and breaks down it can pull oxygen from the water, which stresses or kills fish and other aquatic life [2][4]. Because Cylindro can grow where other algae cannot, it can come to dominate the open water and lower the variety of life a lake supports [2].

Similar species:

At the level of a visible bloom, Cylindro cannot be told apart from other blue-green algae ? discolored water needs a lab test to confirm which species is present [3]. The look-alikes below differ only under a microscope, and none are currently tracked as confusable species in MISIN's database.

Raphidiopsis mediterranea is the closest match ? a straight-filament blue-green alga so similar that scientists now fold it into the same species; only fine microscopic detail separates the two [2].

Aphanizomenon species bloom in the same warm, nutrient-rich lakes and form similar thin filaments, and some make the same liver toxin as Cylindro; the shape of the cells and the position of the resting cells separate them under a microscope [2].

Dolichospermum (also called Anabaena) is another common bloom-forming blue-green alga with thread-like filaments and built-in nitrogen-gathering cells, told apart from Cylindro by its beaded, often coiled strands [2].

Monitoring and rapid response:

Signs to watch for:

1. Water that turns cloudy green, blue-green, or olive during warm, calm weather in late summer or fall [2][3]
2. Discoloration spread through the water rather than just a surface scum [2]
3. Sudden water cloudiness in a lake, pond, or reservoir used for swimming, drinking, or watering livestock [3]

What you can do:

1. When water looks discolored, stay out of it and keep children, pets, and livestock from swimming in or drinking it ? you cannot tell a toxic bloom from a harmless one just by looking [3].
2. If you or a pet do touch bloom water, rinse off with clean, fresh water as soon as possible, and do not let pets lick their fur [3].
3. Do not drink, cook with, or make ice from untreated lake or pond water during a bloom; boiling does not remove the toxin [3].
4. On your own property, cut back on lawn and garden fertilizer, keep septic systems maintained, leave a strip of unmowed plants along the shoreline, and keep grass clippings and yard waste out of the water ? these steps lower the nutrients that feed blooms [4].
5. Clean, drain, and dry boats, trailers, and fishing gear before moving between water bodies, so you do not carry the alga or its resting cells to a new lake [1].
6. Lake associations and natural-area managers can go further across a whole watershed ? monitoring and testing the water, cutting nutrient inputs from surrounding land, and using lake-management methods such as increasing water circulation [1][2].

When to call a professional:

1. A suspected toxic bloom in a lake or pond used for drinking water, swimming, or watering livestock ? contact your local health department or water-quality agency for testing [3].
2. Blooms that return year after year, or any waterbody where treatment is being considered ? a water-quality agency or licensed lake manager should guide the response [2].
3. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. U.S. Geological Survey, Nonindigenous Aquatic Species Database. Raphidiopsis raciborskii (Great Lakes fact sheet). nas.er.usgs.gov
2. Antunes JT, Le?o PN, Vasconcelos VM (2015). "Cylindrospermopsis raciborskii: review of the distribution, phylogeography, and ecophysiology of a global invasive species." Frontiers in Microbiology 6:473. semanticscholar.org
3. U.S. Environmental Protection Agency. What are the effects of HABs? (cyanobacterial toxins and human health). epa.gov
4. U.S. Environmental Protection Agency. What causes HABs? (nutrient pollution and bloom conditions). epa.gov

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