Invasive species pose a serious risk to ecosystem health and stability around the world and locally. Zebra mussels were first detected in the Hudson in 1991. By 1992 they had spread throughout the freshwater and slightly brackish parts of the estuary and had a biomass greater than the combined biomass of all other consumers (fish, zooplankton, zoobenthos, bacteria) in the river. The mussels filter the equivalent of all of the water in the Hudson River about once every four days.
We've assembled three zebra mussel datasets to help you examine the problem from different angles. The first, "Zebra Mussel Populations" (Level 1), simply shows the density of zebra mussels collected in the Hudson each summer for 19 consecutive years. The second, "Zebra Mussels & Other Organisms" (Level 2), allows the user to consider the living community zebra mussels have imbedded themselve in. It includes annual measures of zebra mussels, unionid mussels, phytoplankton, and zooplankton. The third, "Zebra Mussels & Water Chemistry" (Level 3) introduces an abiotic component and shows annual sampled levels of nitrate, phosphate, ammonium, nitrogen, pH, total suspended solids, and turbidity.
You may want to consider starting with one zebra mussel dataset and then adding the others into your analysis as a way of earning the "multiple datasets" bonus.
Data Source: Data collected and compiled by scientists at the Cary Institute of Ecosystem Studies.