Research Product

Marine and estuarine habitats have a great deal of temporal and spatial variability due to the highly complex physical and chemical components that interact with biological components to yield dynamic ecosystems. Salinity differences among component water masses represent one example of the many factors affecting the distribution of the biota within marine and estuarine systems. Salinity differences can range from a few parts per thousand to greater than fifty parts per thousand and commonly establish gradients within an estuary that change over time. This variability sometimes results from predictable and periodic short-term, tidal cycles and longer-term, seasonal changes in physical and chemical forces, such as freshwater inflow, temperature, and wind patterns operating within the ecosystem and at the system boundaries. Other, less predictable forces, such as daily winds, storm events, human intervention, etc., also contribute to temporal and spatial variability within marine systems over short-term and long-term durations and small and large areas. Understanding the effects of pollutants on these ecosystems requires tools that present defined ecosystem boundaries, control and manipulation of many environmental factors and minimal temporal and spatial variability or defined limits for change. These investigation and testing tools, commonly known as microcosms and mesocosms, offer a wide range of complexity in species and ecological make up and sophistication in materials and mechanical engineering for addressing ecotoxicological problems. In this chapter, we provide examples of various types of multispecies test systems that have been used in marine and estuarine studies and discuss their role in ecotoxicological assessments.