TA_range <- round(range(TA_values_50mL, TA_values_75mL)) plot(TA_values_50mL, axes=FALSE, ann=FALSE, ylim=c(min(TA_range), 690), col="blue") axis(1, at=1:length(sample_names), lab=sample_names, cex.axis=0.50) axis(2, c(round(min(TA_values_50mL, TA_values_75mL)), 640, 650, 660, 670, 680, 690)) title(ylab="Total Alkalinity (umol/kg)") lines(TA_values_75mL, pch=22, lty=2, col="red") lines(TA_values_50mL, pch=22, lty=1, col="blue") points(TA_values_75mL, col="red") legend(1, TA_range[2], c("50mL","75mL"), cex=0.8, col=c("blue","red"), lty=1:2) title(main="Effects of Sample Volume on TA Determination\nUsing Instant Ocean", font.main=4)