Cylindrospermopsis raciborskii Factsheet
Scientific Name: Cylindrospermopsis raciborskii (Woloszynska, 1912), Seenayya and Subba Raju, 1972
Common Name: Cylindro
Taxonomy: Available through ITIS
Identification: This species of cyanobacterium (blue-green alga) is composed of trichomes (chained filaments) that are solitary and straight. In Mona Lake, Lake Michigan basin, their tube-shaped cells contain groups of scattered gas vesicles and are divided by barely visible walls (Hong et al. 2006). In other populations, such as in Lake Constance near Ottawa, Ontario, the cell walls are thick and conspicuous (Hamilton et al. 2005). The terminal cells may differentiate into cone-shaped heterocysts. Akinetes (thick-walled spore-like structures) are cylindrical to oval-shaped, found singly or in pairs, near the terminal heterocysts (Hong et al. 2006). Both straight and coiled trichomes of this species exist in different locations around the world. Morphological variation in trichomes, vegetative cells and heterocysts can occur even among very similar genetic isolates of C. raciborskii, depending on abiotic conditions (Saker et al. 1999a; Saker and Neilan 2001; Shafik et al. 2003).
Size: In Mona Lake, trichomes range from 51–311 µm in length and 1.7 – 4.2 µm in width, heterocysts are 5–11 µm by 2–5 µm, and akinetes are 8–16 µm by 2–5 µm (Hong et al. 2006).
Native Range: The genus Cylindrospermopsis is regarded as tropical/subtropical in origin, but it has expanded into temperate areas, particularly the northern hemisphere. The strain of C. raciborskii introduced to the Great Lakes may have originated in South America.
Nonindigenous Occurrences: C. raciborskii was recorded from Mona Lake in 2002 and 2003 as well as Muskegon Lake in 2005, both of which are in the Lake Michigan basin (Hong et al. 2006). This species was also recorded from Lake Erie recently (Conroy et al. 2006). There is one possible record of this species in Lake Erie from 1971 (Taft and Taft 1971) which may have been previously misidentified as Anabaenopsis raciborskii (Kling 2004).
Means of Introduction: Potential modes of introduction of this species to the Lake Michigan watershed include shipping, recreational boating, waterfowl and/or wind dispersal (Hong et al. 2006).
Status: Established.
Ecology: The akinetes of C. raciborskii may persist as spores in the sediments for long periods of time. Akinete formation may be triggered by cold temperatures or large temperature fluctuations and requires high levels of reactive phosphorus (Moore et al. 2003; Moore et al. 2005). Germination occurs more or less synchronously in response to water temperature rising to 22–24°C in temperate regions (Padisak 2003; Hong et al. 2006). Akinetes are probably necessary to stimulate a new season’s growth, providing the initial bloom with concentrated phosphorus. Upon germination, akinetes elongate, split open, and the germling cells that emerge will eventually become trichomes (Moore et al. 2004). Algae blooms consist of trichomes found in and below the euphotic zone, not at the surface (Saker and Griffiths 2001). In tropical or subtropical waters, C. raciborskii is perennial and akinetes rarely develop (Padisak 2003).
Concentrations of this species in Mona and Muskegon Lakes have remained low during late summer sampling, accounting for 6% of phytoplankton count in 2002 and 2003 in the former and ‹1% in 2005 in the latter, possibly due to temperature limitations (Hong et al. 2006). In Constance Lake, Ontario, C. raciborskii blooms appear to be controlled by water temperature and not nutrients (Hamilton et al. 2005).
C. raciborskii can reach very high concentrations (e.g. 176 000 units ml-1 in Newnans Lake, Florida) (Chapman and Schelske 1997). It is capable of fixing atmospheric nitrogen in its heterocysts in response to low cell nitrogen concentration, as well as taking up phosphorus at low concentrations (Shafik et al. 2001; Sprober et al. 2003). The relatively high phosphorus uptake affinity and storage capacity confer C. raciborskii a competitive advantage both in deep lakes with nutrient stratification and in lakes with no such nutrient gradation (Istvanovics et al. 2000). Moreover, this species may also compete well for light in destratified lakes (Antenucci et al. 2005) and artificially mixed reservoirs (Burford et al. 2006).
Conditions that are often associated with blooms of C. raciborskii include: low flow; low water level; low nitrogen to phosphorus ratio; high water temperature; stable thermal stratification; increased retention time; high pH; high sulfate concentration; anoxia in at least some strata; high turbidity; high incident irradiation; and low macrophyte biomass (Ramberg 1987; Bowling 1994; Fabbro and Duivenvoorden 1996; Mayer et al. 1997; McGregor and Fabbro 2000; Saker and Neilan 2001; da Silva et al. 2001; Briand et al. 2002; Bouvy et al. 1999; Tucci and Sant’Anna 2003; Chellappa and Costa 2003; Bormans et al. 2004; Bouvy et al. 2006; Berger et al. 2006; Hong et al. 2006). The optimum temperature for growth is 25–30°C, although growth can occur between 15°C and 35°C, depending on the strain. The optimum light intensity for growth is 80–121 µmol m-2 s-1, but growth occurs at levels as low as 22 µmol m-2 s-1 (Chonudomkul et al. 2004; Briand et al. 2004; Saker and Griffiths 2000; Shafik et al. 2001). The maximum salinity tolerance is 4 g L-1 NaCl (Moisander et al. 2002).
Some strains of this species are capable of producing cylindrospermopsin, a toxic compound that affects the human liver and kidneys, as well as anatoxin-a and saxitoxin, which both act as paralytic shellfish neurotoxins (Schembri et al. 2001). Increased production of cylindrospermopsin is associated with long periods of growth in high light intensity conditions (Dyble et al. 2006), in the presence of a fixed nitrogen source (Saker and Neilan 2001), and at lower water temperatures (Saker and Griffiths 2000).
Impact of Introduction
A) Realized: To date there are no recorded impacts associated with the presence of this species in the Great Lakes basin.
B) Potential: Cylindrospermopsin from toxic C. raciborskii strains has caused liver damage and even death in humans, when the species occurs in water supply systems (Bernard et al. 2003; Falconer and Humpage 2006; Hawkins et al. 1985). Cylindrospermopsin also has the potential to be genotoxic or carcinogenic in humans and to cause acute skin reactions in people on contact (Falconer and Humpage 2001; Falconer and Humpage 2006; Humpage et al. 2000; Shen et al. 2002; Stewart et al. 2006).
This species may have been responsible for fish kills in a reservoir in Brazil (De Souza et al. 1998). A toxic strain is also assumed responsible for cattle deaths in Australia (Saker et al. 1999b; Thomas et al. 1998). In the St. Johns River System, Florida, this cyanobacterium appears to reduce the size and diversity of zooplankton, possibly because nutrients are sequestered or unavailable to grazers in the water column (Leonard and Paerl 2005). Some rotifers and cladocerans exhibit reduced feeding rates, growth rates or growth potential in the presence of C. raciborskii (Hawkins and Lampert 1989; Rothhaupt 1991; Nogueira et al. 2004). C. raciborskii may also cause phytoplankton diversity to decrease, as has been observed in Lake Jesup, Florida (Dobberfuhl 2003) and a pond in Hungary (Borics et al. 2000). Moreover, cylindrospermopsin is known to bioaccumulate in molluscs and crayfish (White et al. 2006; Saker et al. 2004; Saker and Eaglesham 1999) and is toxic to some of these invertebrates (Metcalf et al. 2002). Anatoxin produced by some strains of C. raciborskii has been found to affect snails (Kiss et al. 2002).
By contrast, some rotifers can apparently graze on straight, but not coiled, trichomes of this cyanobacterium (Fabbro and Duivenvoorden 1996), while other rotifers and copepods may cut up filaments to make them edible in size to the entire zooplankton assemblage present (Bouvy et al. 2001).
Remarks: Climate change may be contributing to the expansion of this species in temperate latitudes (Briand et al. 2004; Hamilton et al. 2005). Genetic similarities exist between strains of C. raciborskii from Australia and Europe, Africa and Australia, and North and South America (Dyble et al. 2002; Gugger et al. 2005). The relatively recent colonization of northerly latitudes in North America, including the Great Lakes, probably involves populations originally from South America (Gugger et al. 2005).
Voucher Specimens:
References
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Other Resources
Author: Rebekah M. Kipp
Revision Date: Feb. 19, 2007
Citation for this Information: Rebekah M. Kipp. 2006. GLANSIS.
Group: Phytoplankton (cyanobacteria, or blue-green algae)
Lake(s): Lake Michigan drainage, Lake Erie
Genus: Cylindrospermopsis
Species: raciborskii
Common Name: Cylindro
Status: Established
Freshwater/Marine: Freshwater
Pathway: Unknown (possibly shipping; other possibilities include dispersal by recreational boating, and natural dispersal via waterfowl)
Exotic/Transplant: Exotic
