ABSTRACT
As we are impacting our estuaries and oceans, it is critical that we develop a deep understanding of their dynamics and their ecosystems, and how these systems vary over seasonal and decadal time scales. With an understanding of this variability, we can grasp how our oceans are changing and begin to comprehend the consequences of these changes. To aid our understanding, the latter part of the twentieth century saw the establishment of global and regional scale ocean observing systems. In this chapter, we discuss ocean monitoring across these scales and how the systems use essential ocean variable and short and long term biological indicators to monitor ocean health, with specific examples from Australia and New Zealand.
