Picoplankton in the Bay. Picoplankton are micron-sized, single-cell algae that are an integral component of aquatic ecosystems, both in estuarine and open ocean waters. In the paper “Spatial and Temporal Variability of Picocyanobacteria Synechococcus sp.

in San Francisco Bay” (Limnology and Oceanography, Vol. 45(3), pp. 695–702), X. Ning et al. examined the spatial and temporal dynamics of picoplankton populations in the diverse estuarine environment of San Francisco Bay. Oceanographers classify the Bay into three spatial regions: North, Central, and South. Independent samples of picoplankton in the North and South Bays yielded the following data on concentration in units of 107 cells per liter.

North 16.2 11.2 24.8 36.4 15.0 23.6 12.1 South 9.8 18.7 26.0 7.4 15.0 At the 5% significance level, do the data provide sufficient evidence to conclude that the mean concentrations of the picoplankton populations differ between the North and South Bays?