Zebra mussels (Dreissena polymorpha) are effective sentinels of water quality irrespective of their size

Zebra mussels (Dreissena polymorpha) are recognised biomonitors in determining the presence and viability of the human\ud waterborne pathogens Cryptosporidium parvum, C. hominis, Giardia intestinalis and microsporidia in surface waters. This study\ud investigated whether the size of zebra mussels is a significant factor in the concentration of protozoan Cryptosporidium oocysts,\ud Giardia cysts and microsporidian spores. Zebra mussels were collected in Lough Arrow, a small Irish lake, which is utilized for\ud drinking water abstraction and is subject to agricultural and human wastewater pollution drivers, both recognised risk factors for\ud human waterborne pathogens. Zebra mussels were cleaned, divided into size (5 mm) interval classes based on their shell length\ud and made up to 150 g samples (wet weight with shell). Combined fluorescence in situ hybridization (FISH) and\ud immunofluorescent antibody (IFA) techniques were utilized as biomolecular techniques to assess the presence and concentration\ud of the pathogens. PCR analysis provided source-tracking information on human and animal pollution sources. There was no\ud significant relationship between the size of D. polymorpha and pathogen loads in similar sized samples, indicating that different\ud sites in the same or different waterbody can be compared in terms of relative concentrations of human waterborne parasites\ud irrespective of the zebra mussels’ size. Cryptosporidium was the most abundant species, with lower counts of Giardia and the\ud microsporidian Encephalitozoon hellem, respectively. Cryptosporidium oocysts and Giardia cysts were detected in zebra mussel\ud samples at all three lake water abstraction points. A lake transect showed a decline in Cryptosporidium with increasing distance\ud from a stream discharging sewage. Samples from agricultural sites indicated faecal inputs contaminated with these pathogens.\ud Species identification implicated both human and animal faecal inputs to the lake from treated effluent, septic tanks, and\ud agriculture. The research demonstrates the efficacy of zebra mussels as sentinels of water quality irrespective of their size

Seasonal dynamics of endosymbiotic ciliates and nematodes in Dreissena polymorpha

Abstract We report the results of a two-year study in the Svisloch River (Minsk, Belarus) on the dynamics of infection in Dreissena polymorpha by nematodes and three ciliate species Conchophthirus acuminatus, Ophryoglena sp., and Ancistrumina limnica. Although these endosymbionts were present in most of the samples, their prevalence and infection intensity differed significantly. C. acuminatus and A. limnica infection intensities in both years of the study had a maximum in summer and were positively correlated with water temperature. In contrast, Ophryoglena sp. and nematode infection intensities were considerably lower in summer versus winter and were negatively correlated with temperature. In the first long-term study to monitor the size and reproductive rate of C. acuminatus, we found that mean length was negatively correlated with temperature and that temperature was positively correlated with asexual reproduction, with a peak of cell division in April as water temperatures increased

Evaluating high pH for control of dreissenid mussels

Two field experiments were carried out using a custom built flow-through laboratory to test the effect of elevated pH on dreissenid musselsas a potential control method. Both experiments tested the ability of dreissenid pediveligers to settle under conditions of elevated pH and thelong-term survival of adult dreissenids under the same conditions. The two experimental sites had different water quality and differentspecies of dreissenids present. The settlement of quagga mussel pediveligers at the lower Colorado River was inhibited with increasing pH.At the maximum achieved pH of 9.1, there was approximately 90% reduction compared to the maximum settlement observed in the controls.Since the settlement was almost as low in pH 8.9 as at pH 9.1, the inhibition in settlement may have been due to the presence of a precipitateformed under high pH conditions rather than the increase in background pH. No mortality of quagga mussel adults was observed in theexperimental pH levels at the lower Colorado River. At San Justo Reservoir, zebra mussel settlement decreased with increasing pH. Newsettlement was almost entirely absent at the highest pH tested (pH 9.6). The observed mortality of adult zebra mussels was low, but did tendto increase with increasing pH. We also tested the response of adult zebra mussels to short-term exposure to very high pH levels (i.e. pH 10,11, and 12). Adult mussels in poor physical condition experienced 90% mortality after 12 hours at pH 12. For unstressed adult zebra mussels,90% mortality was reached after 120 hours at pH 12. Significant mortalities were also observed both at pH 10 and pH 11. From this study,we conclude that pH elevation could be used both as a preventative treatment to eliminate settlement by dreissenid mussels and as an end ofseason treatment to eliminate adults. The high pH treatment would have to be tailored to the site water quality to prevent formation ofprecipitate during treatment and to minimize corrosive action on materials of construction

\u3ci\u3eAquastella gen. nov.\u3c/i\u3e: A new genus of saprolegniaceous oomycete rotifer parasites related to \u3ci\u3eAphanomyces\u3c/i\u3e, with unique sporangial outgrowths

The oomycete genus Aquastella is described to accommodate two new species of parasites of rotifers observed in Brooktrout Lake, New York State, USA. Three rotifer species – Keratella taurocephala,Polyarthra vulgaris, and Ploesoma truncatum – were infected, and this is the first report of oomycete infection in these species. Aquastella attenuata was specific to K. taurocephala and Aquastella aciculariswas specific to P. vulgaris and P. truncatum. The occurrence of infections correlated with peak host population densities and rotifers were infected in the upper layers of the water column. Sequencing of 18S rRNA and phylogenetic analysis of both species placed them within the order Saprolegniales, in a clade closely related to Aphanomyces. The Aquastella species were morphologically distinct from other rotifer parasites as the developing sporangia penetrated out through the host body following its death to produce unique tapered outgrowths. Aquastella attenuata produced long, narrow, tapering, finger-like outgrowths, whilst A. acicularis produced shorter, spike-like outgrowths. We hypothesize that the outgrowths serve to deter predation and slow descent in the water column. Spore cleavage was intrasporangial with spore release through exit tubes. Aquastella attenuata produced primary zoospores, whereas A. acicularisreleased spherical primary aplanospores, more typical of other genera in the Aphanomyces clade

Infection of the zebra mussel with its commensal ciliate Conchophthirus acuminatus

<p>This dataset contains records of infection of the invasive bivalve mollusc Dreissena polymorpha (zebra mussel) with its commensal ciliate Conchophthirus acuminatus. For more details see the original publication:</p> <p>Mastitsky SE (2012) Infection of Dreissena polymorpha (Bivalvia: Dreissenidae) with Conchophthirus acuminatus (Ciliophora: Conchophthiridae) in lakes of different trophy. BioInvasions Records 1(3): 161-169</p> <p>The following variables are included in the dataset:</p> <p>- Month: sampling month</p> <p>- Day: sampling day, starting from 0 - the first day of study</p> <p>- Lake: the waterbody sampled</p> <p>- Site: sampling site within Lake</p> <p>- Length: shell length of the dissected zebra mussels (mm)</p> <p>- Infection: number of the ciliates Conchophthirus acuminatus found in a mollusc</p

Larvae of Chironomids (Insecta, Diptera) En-countered in the Mantle Cavity of Zebra Mussels, Dreissena polymorpha (Bivalvia, Dreisse-nidae) // Internat. Rev. Hydrobiol. – № 90. – 2005. – P. 42-50.

The paper includes data on species composition of chironomid larvae which were encountered in the mantle cavity of zebra mussels (Dreissena polymorpha) within 7 waterbodies in the Republic of Belarus. All were found to be free-living species commonly present in periphyton and/or benthos. A long-term study of the seasonal dynamics of these larvae in Dreissena did not reveal any typical pattern. Our data suppose that chironomids do not have an obligate association with zebra mussels and possibly enter their mantle cavity inadvertently

First report of endosymbionts in Dreissena polymorpha from the brackish Curonian Lagoon, SE Baltic Sea**This study was supported by the European Regional Development Fund through the Baltic Sea Region Programme project ‘Sustainable Uses of Baltic Marine Resources’ (SUBMARINER No. 055).

AbstractWe report the first results of a parasitological study of Dreissena polymorpha (zebra mussels) from the brackish Curonian Lagoon, SE Baltic Sea. Zebra mussels were collected monthly from May to October 2011 from a site near the mouth of the River Nemunas. Three types of endosymbionts were found in the mantle cavity and visceral mass of the molluscs during dissections, i.e. the commensal ciliate Conchophthirus acuminatus and parasitic ciliate Ophryoglena sp., and rarely encountered, unidentified nematodes. The abundances of C. acuminatus and Ophryoglena sp. were positively associated with host shell length and water temperature, but no effect of water salinity was detected. As the endosymbionts are either highly host-specific to zebra mussels (C. acuminatus and Ophryoglena sp.) or are probably free-living organisms that inadvertently infect the molluscs (nematodes), we conclude that the presence of D. polymorpha in the Curonian Lagoon does not pose any serious parasitological risk to native biota. We emphasize, however, that this conclusion should be treated with caution as it is based on a study conducted only at a single location. Our work extends the currently scarce records of D. polymorpha parasites and commensals from brackish waters, and adds to a better understanding of the ecological impact this highly invasive mollusc causes in the areas it has invaded

Parasites of Aquatic Exotic Invertebrates: Identification of Potential Risks Posed to the Great Lakes

<div><p>ABSTRACT</p><p>Exotic species typically lose most of their associated parasites during long-distance spread. However, the few parasites that are co-introduced may have considerable adverse impacts on their novel hosts, including mass mortalities. We present a comprehensive inventory of parasites known to infect 38 species of exotic invertebrates established in the Great Lakes, as well as 16 invertebrate species predicted to arrive in the near future, all of them crustaceans. Based on a literature analysis, we identified a total of 277 parasite taxa associated with the examined invertebrates in their native ranges and/or invaded areas. Of these parasites, 56 species have been documented to cause various pathologies in their intermediate or final hosts, with humans and fishes being the most frequently affected host categories. Potentially harmful parasites were identified in 61% of the invaders for which published information was retrieved (in their ranges outside of the Great Lakes), with molluscs and crustaceans hosting the highest numbers of such parasites. The results of our study provide a baseline for further assessment and management of the parasitological risks posed by exotic species to the Great Lakes.</p> </div

Cross-effects of nickel contamination and parasitism on zebra mussel physiology

International audienc

Supplement 1. R code and the data set necessary to conduct the Random Forest analysis.

<h2>File List</h2><div> <p><a href="dreissena_in_lakes_of_belarus.csv">dreissena_in_lakes_of_belarus.csv</a> (MD5: 3dc2d2f89af3064223358983c785771d)</p> <p><a href="r_script_random_forest.R">r_script_random_forest.R</a> (MD5: af1295890d60bc832955e940889e4575)</p> </div><h2>Description</h2><div> <p>This Supplementary material contains two files necessary to fully reproduce the results obtained using the Random Forest classifier. The first of these files, dreissena_in_lakes_of_belarus.csv, is a plain text table that has 553 records, each described with the following variables:</p> <p>1. Lake_Code: numeric codes uniquely identifying each lake (for reference only, not used in analysis explicitely).</p> <p>2. ZMpresence: indicator of whether a lake is infested with zebra mussel (0 – for non-infested, 1 – for infested).</p> <p>3. LAREA: lake area</p> <p>4. LVOL: lake volume</p> <p>5. MAXD: maximal depth</p> <p>6. AVED: average depth</p> <p>7. SPECWATSHED: specific watershed (i.e., drainage area)</p> <p>8. TRANSP: Secci depth</p> <p>9. COLOR: water color</p> <p>10. pH: water pH</p> <p>11. HCO3: HCO3 content</p> <p>12. SO4: SO4 content</p> <p>13. Cl: CL content</p> <p>14. Ca: Ca content</p> <p>15. Mg: Mg content</p> <p>16. TDS: total dissolved solids</p> <p>17: Fe: Fe content</p> <p>18. Si: Si content</p> <p>19. NH4: NH4 content</p> <p>20. NO2: NO2 content</p> <p>21. PO4: PO4 content</p> <p>22. PermOx: permanganate oxydizability</p> <p>23. N: latitude (decimal degree)</p> <p>24: E: longitude (decimal degree)</p> <p>Missing values in the data set are denoted as NA. </p> <p>The second file, r_script_random_forest.R, loads the data into R (assuming that the file dreissena_in_lakes_of_belarus.csv is stored in the current R working directory), fits the Random Forest model, and plots the results. The analysis relies on three add-on packages: caret, geosphere, randomForest, and ggplot2. All these packages are assumed to be already installed on the user's computer (if not, they can be freely downloaded from the Comprehensive R Archive Network, cran.r-project.org, or installed directly from within R using the following command: install.packages(c("caret", "geosphere", "randomForest", "ggplot2"))). </p> </div