IVARS
type: Concept
in scheme: projects
definition: The Ross Sea, a marginal Antarctic sea south of New Zealand, has been studied since the days of the Scott/Amundsen expeditions. It is the site of extensive penguin, bird and mammal colonies, and also the home of two significant scientific bases, McMurdo Station (US) and Stazione Baia de Terra Nova (Italy). Its oceanography is relatively well known, including ... the physical oceanography and hydrography, nutrient concentrations (nitrate and silicic acid), and phytoplankton biomass and species composition. However, marked variations in these variables occur spatially and temporally. Indeed, the variations with time are the greatest factor in the Ross Sea habitat. For example, throughout much of the winter the Ross Sea is ice covered, and no incident radiation is available to drive photosynthesis. In contrast, during the summer months the Ross Sea is ice-free, and large accumulations of phytoplankton biomass occur. In addition to these seasonal changes, variations among years occur in all oceanographic variables, whether they be current velocities and directions, ice concentration, winds, or phytoplankton productivity. The causes and consequences of these interannual variations, however, are poorly known. They likely have both local and remote drivers; that is, ice concentrations are likely controlled by the Antarctic circumpolar wave observed by White et al. (1999), as well as by basin-wide changes induced by El Nino. Regardless of the causes, the degree of variation among years in biological variables is unknown, and this is what IVARS seeks to explore. Ultimately we hope to understand not only the causes, but also the consequences to the food web of the region. How will we assess the interannual differences in biological processes? We first will collect as much historical data from the region from various cruises conducted in the past three decades and generate a climatology or long-term mean of both nutrients (nitrate and silicic acid) and chlorophyll concentratio…

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type: Concept