DOI: 10.5061/dryad.fn2z34v6f
title: No evidence of an allelopathic effect of Eurasian watermilfoil (<em>Myriophyllum spicatum</em>) on cyanobacteria in natural lakes

description: Eurasian watermilfoil (Myriophyllum spicatum) is an exotic vascular plant
 in North America and highly invasive in lacustrine environments. This
 plant forms dense, extensive beds that can interfere with recreational
 activities. High concentrations of Eurasian watermilfoil have been shown
 in laboratory experiments to cause mortality or low growth rates to
 several species of cyanobacteria, because of allelopathic molecules (fatty
 acids, polyphenols) released into the water by the plant. The main
 objective of this study was to verify whether a causal link between
 Eurasian watermilfoil and cyanobacteria could be established in two
 infested lakes of southern Québec, Canada. Some fatty acids or polyphenols
 (ellagic, nonanoic, octadecenoic, and oleic acids) were detected in summer
 and autumn in the water, but in concentrations well below (30 to 35 000
 times lower) the theoretical concentrations at which they reduce the
 growth of cyanobacteria. There was no evidence of allelopathic effects of
 Eurasian watermilfoil on the cyanobacterial assemblages. However, some
 cyanobacterial species known to be influenced by Eurasian watermilfoil, in
 particular Microcystis aeruginosa, were not specifically identified in
 this study, so caution must be exercised before concluding that there is
 no allelopathic effect.
description: # No evidence of an allelopathic effect of Eurasian watermilfoil
 (*Myriophyllum spicatum*) on cyanobacteria in natural lakes Dataset DOI:
 [10.5061/dryad.fn2z34v6f](https://doi.org/10.5061/dryad.fn2z34v6f) ##
 Description of the data and file structure These data were collected as
 part of a field study investigating whether the invasive aquatic plant
 Eurasian watermilfoil (*Myriophyllum spicatum*) exerts allelopathic
 effects on cyanobacterial assemblages in natural lake systems. The dataset
 includes: * Quantification of specific allelochemicals (fatty acids and
 polyphenols) in water samples * Cyanobacterial cell abundance and
 assemblage data (to genus level) from water samples collected at sites
 with and without *M. spicatum* beds; * Associated physicochemical
 parameters (e.g., total nitrogen, total phosphorus, nitrite–nitrate, water
 temperature, dissolved oxygen) from the same sampling locations and
 periods. ### Files and variables #### Bergeron_Data.csv METADATA: Name
 (Unit): Description Date: Date of the sampling Outing: Field outing number
 Lake: Name of the lake Replicate: Replicate Site: Name of the site Sample
 number: Number of the sample Id: Id of the sample Precipitation:
 Qualitative description of precipitation conditions prior to the sampling
 event. Sky condition: Visual observation of sky conditions at the time of
 sampling. Wave type: Visual assessment of surface water conditions based
 on wave activity during sampling. Wind direction: Cardinal direction from
 which the wind is blowing at the time of sampling. Water level (m): Water
 level at the lake outlet, at the Cyrille-Delage dam Precipitation (mm):
 Daily precipitation on the sampling day. Cumulative precipitation (mm):
 Total cumulative precipitation since January 1st Cumulative degree-days
 (°C): Cumulative degree-days (above 0°C) since January 1st Start time:
 Sampling start time. End time: Sampling end time. Average wind speed
 (m/s): Average wind speed at sampling site Maximum wind speed (m/s):
 Maximum wind speed at sampling site Maximum depth (m): Maximum depth at
 sampling site Atmospheric pressure (mmHg): Atmospheric pressure at
 sampling site Air temperature (°C): Air temperature at sampling site Water
 transparency (m): Water transparency at sampling site 0 m Water
 temperature (°C): Water temperature at the surface 0 m pH: pH at the
 surface 0 m ORP (mV): Redox potential at the surface 0 m Conductivity
 (ms/cm): Conductivity at the surface 0 m Dissolved oxygen (%): Dissolved
 oxygen percentage at the surface 1 m Water temperature (°C): Water
 temperature at a depth of one meter 1 m pH: pH at a depth of one meter 1 m
 ORP (mV): Redox potential at a depth of one meter 1 m Conductivity
 (ms/cm): Conductivity at a depth of one meter 1 m Dissolved oxygen (%):
 Dissolved oxygen percentage at a depth of one meter 2 m Water temperature
 (°C): Water temperature at a depth of two meters 2 m pH: pH at a depth of
 two meters 2 m ORP (mV): Redox potential at a depth of two meters 2 m
 Conductivity (ms/cm): Conductivity at a depth of two meters 2 m Dissolved
 oxygen (%): Dissolved oxygen percentage at a depth of two meters 3 m Water
 temperature (°C): Water temperature at a depth of three meters 3 m pH: pH
 at a depth of three meters 3 m ORP (mV): Redox potential at a depth of
 three meters 3 m Conductivity (ms/cm): Conductivity at a depth of three
 meters 3 m Dissolved oxygen (%): Dissolved oxygen percentage at a depth of
 three meters Ammoniacal nitrogen (µg N/l): Concentration of ammoniacal
 nitrogen in the water column Nitrites and nitrates (mg N/l): Concentration
 of nitrites and nitrates in the water column Total phosphorus (µg P/l):
 Concentration of total phosphorus in the water column Total nitrogen (mg
 N/l): Concentration of total nitrogen in the water column Dissolved
 orthophosphates (µg P/l): Concentration of dissolved orthophosphates in
 the water column; NULL means no dissolved orthophosphates were detected
 Nonanoic acid (µg/l): Concentration of nonanoic acid in the water column
 LOD:Limite of detection Oleic acid (µg/l): Concentration of oleic acid in
 the water column LOQ: Limit of Quantification Octadecenoic acid (µg/l):
 Concentration of octadecenoic acid in the water column Gallic acid (µg/l):
 Concentration of gallic acid in the water column Pyrogallol (µg/l):
 Concentration of pyrogallol in the water column Catechine (µg/l):
 Concentration of catechine in the water column Eugeniine (µg/l):
 Concentration of eugeniine in the water column Ellagic acid (µg/l):
 Concentration of ellagic acid in the water column Cyanobacteria (cell/ml):
 Concentration of cyanobacteria in the water column Anabeanopsis (cell/ml):
 Concentration of *Anabeanopsis* in the water column Aphanizomenon sp.
 (cell/ml): Concentration of *Aphanizomenon* sp in the water column
 Aphanocapsa sp. (cell/ml): Concentration of *Aphanocapsa* sp in the water
 column Aphanothece sp. (cell/ml): Concentration of *Aphanothece* sp in the
 water column Borzia sp. (cell/ml): Concentration of *Borzia* sp in the
 water column Chroococcus sp. (cell/ml): Concentration of *Chroococcus* sp
 in the water column Coelomoron sp. (cell/ml): Concentration of
 *Coelomoron* sp in the water column Coelosphaerium sp. (cell/ml):
 Concentration of *Coelosphaerium* sp in the water column Cuspidothrix sp.
 (cell/ml): Concentration of *Cuspidothrix* sp in the water column
 Cyanodictyon sp. (cell/ml): Concentration of *Cyanodictyon* sp in the
 water column Cyanogranis sp. (cell/ml): Concentration of *Cyanogranis* sp
 in the water column Cylindrospermopsis sp. (cell/ml): Concentration of
 *Cylindrospermopsis* sp in the water column Cylindrospermum sp. (cell/ml):
 Concentration of *Cylindrospermum* sp in the water column Dolichospermum
 sp. (Anabena sp.) (cell/ml): Concentration of *Dolichospermum* sp
 *Anabena* sp in the water column Eucapsis sp. (cell/ml): Concentration of
 *Eucapsis* sp in the water column Geitlerinema sp. (cell/ml):
 Concentration of *Geitlerinema* sp in the water column Gloeocapsa sp.
 (cell/ml): Concentration of *Gloeocapsa* sp in the water column
 Gomphospheria sp. (cell/ml): Concentration of *Gomphospheria* sp in the
 water column Jaaginema sp. (cell/ml): Concentration of *Jaaginema* sp in
 the water column Komvophoron sp. (cell/ml): Concentration of *Komvophoron*
 sp in the water column Lemmermaniella sp. (cell/ml): Concentration of
 *Lemmermaniella* sp in the water column Leptolyngbya sp. (cell/ml):
 Concentration of *Leptolyngbya* sp in the water column Limnothrix sp.
 (cell/ml): Concentration of *Limnothrix* sp in the water column Lyngbya
 sp. (cell/ml): Concentration of *Lyngbya* sp in the water column
 Merismopedia sp. (cell/ml): Concentration of *Merismopedia* sp in the
 water column Microcystis sp. (cell/ml): Concentration of *Microcystis* sp
 in the water column Oscillatoria sp. (cell/ml): Concentration of
 *Oscillatoria* sp in the water column Phormidium sp. (cell/ml):
 Concentration of *Phormidium* sp in the water column Planktolyngbya sp.
 (cell/ml): Concentration of *Planktolyngbya* sp in the water column
 Planktothrix sp. (cell/ml): Concentration of *Planktothrix* sp in the
 water column Pseudanabaena sp. (cell/ml): Concentration of *Pseudanabaena*
 sp in the water column Rhabdoderma sp. (cell/ml): Concentration of
 *Rhabdoderma* sp in the water column Rhabdogloea sp. (Dactylococcopsis
 sp.) (cell/ml): Concentration of *Rhabdogloea* sp in the water column
 Radiocystis sp. (cell/ml): Concentration of *Radiocystis* sp in the water
 column Raphidiopsis sp. (cell/ml): Concentration of *Raphidiopsis* sp in
 the water column Snowella sp. (cell/ml): Concentration of *Snowella* sp in
 the water column Spirulina sp. (cell/ml): Concentration of *Spirulina* sp
 in the water column Synechococcus sp. (cell/ml): Concentration of
 *Synechococcus* sp in the water column Synechocystis sp. (cell/ml):
 Concentration of *Synechocystis* sp in the water column Woronichinia sp.
 (cell/ml): Concentration of *Woronichinia* sp in the water column Other
 blue-green algae (cell/ml): Concentration of other blue-green algae in the
 water column ## Code/software Data analyses were conducted using two main
 software environments: 1. **Stata version 16.0** (StataCorp, 2019) * Used
 for the multiple regression and panel data analyses. * Included procedures
 for random effects models with spatial fixed effects, Breusch–Pagan and
 Pesaran tests for cross-sectional dependence, heteroscedasticity testing
 (Breusch–Pagan), normality testing of residuals (Shapiro–Wilk and
 histogram inspection), and multicollinearity assessment using the Variance
 Inflation Factor (VIF). * Based on the VIF results, two variables
 (cumulative degree-days and air temperature) were removed from the final
 model. 2. **R version 2023.06.2** (The R Project for Statistical
 Computing, 2023) * Used for the analysis of variance (two-way ANOVA, model
 1) to compare cyanobacterial concentrations between sampling dates and
 sites with vs. without *Myriophyllum spicatum*. * Implemented functions: *
 `aov()` for ANOVA * `shapiro.test()` for residual normality (Shapiro–Wilk
 test) * `leveneTest()` (from the *car* package) for homogeneity of
 variances. * A canonical correspondence analysis (CCA) was also performed
 using the function `cca()` from the **vegan** package (version 2.6-4;
 Oksanen et al., 2022) to explore relationships between cyanobacterial
 assemblages and environmental variables. All analyses used freely
 available or licensed software as noted above. No custom scripts were
 developed; only standard functions and statistical packages were used. ##
 Access information Other publicly accessible locations of the data: *
 Gouvernement du Québec. (2023b). *Niveau d’eau et débit.* Ministère de
 l’Environnement, de la Lutte contre les changements climatiques, de la
 Faune et des Parcs du Québec.
 [https://www.cehq.gouv.qc.ca/hydrometrie/](https://www.cehq.gouv.qc.ca/hydrometrie/) * Environnement Canada. (2023). *Données historiques.* Gouvernement du Canada.  [https://climat.meteo.gc.ca/historical_data/search_historic_data_f.html](https://climat.meteo.gc.ca/historical_data/search_historic_data_f.html)