analysis to determine temporal trends can begin with graphic representation of data(time on the x-axis) and may range from diurnal to seasonal and longer cycles. spectral analysis, which finds peaks in the variability of the data that is explained by cycles of different lengths, is a powerful tool to determine temporal patterns. a form of spectral analysis was used by duarte et al. to historically reconstruct the age of seagrass shoots from internodes they removed intra-annual and broad decadal difference in internode lengths through regression analysis. the residuals that remained demonstrate a sinusoidal pattern where peaks represent annual growth