Acute toxicity of glyphosate on various life stages of calanoid copepod, Pseudodiaptomus annandalei

Abstract

Copepods are one of the most important primary producers and biodiversity indicators. They are also highly susceptible to various toxicants. In this study, glyphosate (Roundup®), a widely used herbicide was used to investigate the toxicity effect on calanoid copepods, Pseudodiaptomus annandalei, focused on their nauplius, copepodid, and adult stages. Different concentrations of glyphosate (i.e. 0 - as control, 0.05, 0.1, 0.4, 1.6, 6.4 and 25.6 mg/L) were used to elucidate the tolerance level of P. annandalei. The survival rate of copepod was recorded at the intervals of 24, 48, 72 and 96 h after glyphosate exposure. The analysis was performed using probit test to determine the sub-lethal concentrations. Our results revealed that LC50 of the nauplius stage was recorded as 3.47, 3.02, 1.86 and 1.10 mg/L at 24, 48, 72 and 96 h, respectively. Higher LC50 values were recorded at 4.36 mg/L for 24 h, 3.09 mg/L for 48 h, 2.00 mg/L for 72 h, and 1.12 mg/L for 96 h at the copepodid stage. Generally, adult copepods showed a higher level of tolerance to glyphosate among all stages, whereby at this stage LC50 values were recorded as 11.70 mg/L for 24 h,10.23 mg/L for 48 h, 7.41 mg/L for 72 h, and 3.61 mg/L for 96 h, respectively. Our results indicated that prolong exposure time of glyphosate could increase the susceptibility of P. annandalei to the herbicide. Nauplii are the most sensitive group among all. This study showed that glyphosate could post significant eco-toxicological impact to the non-targeted organism.

Widespread agrochemicals differentially affect zooplankton biomass and community structure

“…Information on rotifers is relatively limited (Appendix : Table S1), but our results are consistent with other studies of glyphosate toxicity on copepods, with notably greater sensitivity found in immature stages as compared to adults (Lim et al. 2019). While compelling evidence has accrued for acute and chronic toxicity in cladocerans at similar concentrations of glyphosate (e.g., ranges of LC 50 for Daphnia and Ceriodaphnia : 0.45–10.6 and 4.8–6.05 mg/L, respectively; Tsui and Chu 2003, Cuhra et al.…”

“…The general patterns of species turnover in communities exposed to glyphosate (alone or in combination) highlighted a stark contrast between sensitive rotifer (long-lasting declines at concentrations ≥0.3 mg/L) and copepod zooplankton (partial recovery over time, but none ≥5.5 mg/L), and highly tolerant cladocerans, with Alona, Chydorus, and Scapholeberis still thriving under severe glyphosate contamination, even in the presence of imidacloprid. Information on rotifers is relatively limited (Appendix S1: Table S1), but our results are consistent with other studies of glyphosate toxicity on copepods, with notably greater sensitivity found in immature stages as compared to adults (Lim et al 2019). While compelling evidence has accrued for acute and chronic toxicity in cladocerans at similar concentrations of glyphosate (e.g., ranges of LC 50 for Daphnia and Ceriodaphnia: 0.45-10.6 and 4.8-6.05 mg/L, respectively; Tsui andChu 2003, Cuhra et al 2013), such observations mostly rely on single-species cultures in a laboratory setting, with few to no studies using the most tolerant species found in our ponds.…”

Widespread agrochemicals differentially affect zooplankton biomass and community structure

“…The general patterns of species turnover in communities exposed to glyphosate (alone or in combination) highlighted a stark contrast between sensitive rotifer (long-lasting collapse at concentrations ≥0.3 mg/L) and copepod zooplankton (partial recovery over time, but none ≥5.5 mg/L), and highly tolerant cladocerans, primarily belonging to Alona, Chydorus, and Scapholeberis (still thriving at 15mg/L of glyphosate, even in the presence of imidacloprid). Information on rotifers is relatively limited (Table S1), but our results are consistent with other studies of glyphosate toxicity on copepods, with notably greater sensitivity found in immature stages as compared to adults (Lim et al, 2019). While compelling evidence has accrued for acute and chronic toxicity in cladocerans at similar concentrations of glyphosate (Table S1; e.g., ranges of LC50 for Daphnia and Ceriodaphnia: 0.45-10.6 and 4.8-6.05 mg/L, respectively; Cuhra et al, 2013;Tsui & Chu, 2003), such observations mostly rely on single-species cultures in a laboratory setting, with few to no studies using the most tolerant species in our ponds.…”

Acute and Chronic Effects of a Glyphosate and a Cypermethrin-Based Pesticide on a Non-Target Species Eucypris sp. Vavra, 1891 (Crustacea, Ostracoda)

“…is even more resistant than the freshwater copepod A. robustus, for which the LC 50 is 19 ppm and 13 ppm in 24 h and 48 h, respectively [3]. This herbicide in its Roundup ® formulation also showed greater toxicity on the copepod Pseudodiaptomus annandalei (LC 50 11.7 ppm and 10.23 ppm in 24 and 48 h, respectively) [24] than on the ostracod observed in the current study. On the other hand, Eucypris sp.…”

“…Among herbicides, glyphosate is the most widely used in agriculture [22] in different formulations. Its effects in the aquatic environment have been reported for several species [3,23,24]. It induces a reduction in reproduction in the water flea Daphnia magna [25].…”