# Can _Hediste diversicolor_ Speed Up the Breakdown of Cigarette Butts in Marine Sediments?
## 3 Results
### Biological Parameters  
Although the two CB concentrations tested did not affect the survival of _H. diversicolor_, there was an interaction between this factor and time (_p_ < 0.05, Table 3). As shown in Figure 2, the mortality of polychaetes exposed to CB increases with time, especially in those exposed to summer temperatures (23 \({}^{\circ}\)C). Indeed, both temperature (_p_ < 0.001) and time (_p_ < 0.0001) significantly reduced polychaete survival, with an interaction between these two factors. The survival of control polychaetes at 15 \({}^{\circ}\)C is significantly different from that of CB treatments after 21 days of exposure (_p_ < 0.05). In contrast, the differences between control survival at 23 \({}^{\circ}\)C and the lower CB concentration tested are significant after 7 days of exposure. _Hediste_ survivals of all treatments at 15 \({}^{\circ}\)C are significantly different from their respective treatments at 23 \({}^{\circ}\)C. \begin{table}
\begin{tabular}{l l l l l l l} \hline  & & **df** & **SS** & **MS** & **F** & **_p_ \\ \hline \multirow{8}{*}{Mortality rate} & Time & 1.32 & 8496.72 & 8496.70 & 21.91 & 0.0001 \\  & Time \(\times\) CBs & 2.63 & 1324.99 & 1324.99 & 3.42 & 0.0440 \\  & Time \(\times\) Temperature & 1.32 & 6205.38 & 6205.38 & 16.00 & 0.0001 \\  & Error (Time) & 42 & 387.77 & 170.20 & - & - \\  & CBs & 2.00 & 7430.71 & 3715.36 & 3.500 & ns \\  & Temperature & 1.00 & 19.181.87 & 19,181.87 & 18.10 & 0.0010 \\  & Error & 14 & 14,843.52 & 1070.25 & - & - \\ \hline \multirow{8}{*}{Burrowing behavior} & Time & 2.45 & 24,140 & 24,140.29 & 1.65 & ns \\  & Time \(\times\) CBs & 4.40 & 67,741.38 & 13,010.80 & 2.30 & ns \\  & Time \(\times\) Temperature & 2.40 & 28,048.55 & 11,436.80 & 1.90 & ns \\  & Error (Time) & 56 & 205,169.38 & 5975.56 & - & - \\  & CBs & 2.00 & 58,063.40 & 29,031.70 & 4.70 & 0.0270 \\  & Temperature & 1.00 & 36,200.28 & 36,200.28 & 5.90 & 0.0290 \\  & Error & 14 & 85,485.62 & 6106.18 & - & - \\ \hline \multirow{8}{*}{Burial rate} & Time & 2.00 & 119,836.15 & 57,548.40 & 3.60 & 0.0370 \\  & Time \(\times\) CBs & 4.20 & 54,932.31 & 54,932.31 & 0.84 & ns \\ \cline{1-1}  & Time \(\times\) Temperature & 2.10 & 42,614.38 & 20,464.52 & 1.30 & ns \\ \cline{1-1}  & Error (Time) & 56 & 458,695.55 & 8190.99 & - & - \\ \cline{1-1}  & CBs & 2.00 & 23,835.47 & 11,917.73 & 0.82 & ns \\ \cline{1-1}  & Temperature & 1.00 & 77,088.40 & 77,088.40 & 5.32 & 0.0370 \\ \cline{1-1}  & Error & 14 & 20,2705.33 & 14,478.95 & - & - \\ \hline \end{tabular}
\end{table} 
Table 3: Results of the three-factor repeated-measures ANOVA for the mortality, burrowing behaviour, and burial rate of _Hediste diversicolor_ exposed to the different CB concentrations (0 CBL\({}^{-1}\), 0.25 CBL\({}^{-1}\), 1 CBL\({}^{-1}\)) and at the two temperatures studied (15 \({}^{\circ}\)C, 23 \({}^{\circ}\)C) for 28 days. Sum square (SS); mean square (MS); degrees of freedom (df); ns = nonsignificant. _H. diveriscolor_ exposed to CB concentrations at 23 \({}^{\circ}\)C reduced their burial success by 33% compared with controls after only 7 days of exposure. This reduction was maintained until day 21 of the experiment in polychaetes exposed to 0.25 CBL\({}^{-1}\), while the difference between those exposed to 1 CBL\({}^{-1}\) and the controls increased to 66% at 14 and 21 days of exposure. Indeed, regardless of time, both the CB concentration and temperature similarly affected the burial behaviour of _Hediste_, as there is no interaction between these two factors (Table 3). Polychaetes from both CB concentrations began to burrow into the sediment significantly later than those from the control throughout the experiment (Figure 3A). Except for those polychaetes that were unsuccessful in burrowing, the mean time needed to start digging was shorter for polychaetes at 23 \({}^{\circ}\)C. Temperature also affected the burial rate of _H. diveriscolor_, as did exposure time (Table 3).