Chemical reference-profiles from 20 years of Santander Standard Section

Abstract

Since 1991, Spanish Institute of Oceanography (IEO), within the RADIALES time-series monitoring program, has monthly sampled key oceanographic variables in 5 standard sections around the Galician and Cantabrian coast. In the framework of the European Marine Observation and Data Network (EMODnet) project, the IEO has performed an important effort to validate and control its biogeochemical data collections. This study is focused on chemical data from the Santander standard section, which covers coastal, shelf-break and oceanic waters. One of its goals is to describe the chemical behavior of the area and its variability along the time, including as short changes as long-term ones. Early detection of variations in nutrient concentrations is essential to predict the ecosystem responses. To reach these objectives a 20-years dataset (1991-2012) has been validated and flagged according to internationally accepted quality criteria. This dataset is used to define chemical reference-profiles for each station and to determinate their seasonal variability . The analyzed variables were nitrates, nitrites, phosphates, ammonium, silicates and dissolved oxygen. This reference profiles are a useful tool to validate future data on the area and to compare environmental conditions in order to determinate changes not only explained by seasonal variability.