But there are still few ecological time series, in particular species-level data for the plankton that form the base of marine food webs. Some of the strongest evidence of climate-linked changes in zooplankton abundance has come from the Continuous Plankton Recorder (CPR) survey of the North Sea and north Atlantic, dating to 1946.
Next year, the United Nations aims to complete its first World Ocean Assessment, a process akin to the regular reporting of the Intergovernmental Panel on Climate Change.The assessment is timely and crucial: the world's oceans are threatened by many anthropogenic stressors, from pollutants, nutrient runoff and overfishing to warming, deoxygenation and acidification Variables such as temperature, salinity and chlorophyll levels are monitored globally by satellites, water-column-profiling floats and moored sensor arrays.As a joint programme between the Scripps Institution of Oceanography in La Jolla, California, and the state and federal agencies responsible for fisheries since 1949, Cal COFI's quarterly acoustic and egg and larval surveys provide data to assess commercial species such as sardine, anchovy and hake.From the outset, the Cal COFI surveys have been embedded in a suite of observations of the fishes' physical and biological environments.As part of the open-ocean GOOS programme, the Argo project successfully seeded the world's oceans with some 3,000 floats to profile temperature and salinity.
But the coastal GOOS programmes focused on easy observations and local hazards. The United States, for example, is served by 11 regional associations, each with its own instrumentation.Today, there are just two ecological data sets that are sufficiently long to fit the bill — and each has limitations.A global ocean-observation network needs to be established within the next five years to provide baselines against which ocean health can be assessed in the coming century.Alongside physical oceanographic data, such a network must track the status of species in marine ecosystems around the world.Ecological time series are the Cinderellas of ocean science: long-neglected drudges, eking out their existence at the edge of what is in fashion, they now find themselves in favour at the climate change ball.On setting up a special session at the 2012 annual meeting of the North Pacific Marine Science Organization to examine trends across the northern Pacific, where similar oxygen declines had been reported, it emerged that there are no other time-series data sets for the mid-water fauna.