Continuous plankton records: Plankton atlas of the North Atlantic Ocean (1958-1999). I. Introduction and methodology

The Continuous Plankton Recorder (CPR) survey is one of the largest plankton monitoring programmes in the world. Data from this programme have been used to investigate many ecological issues such as biogeography, biodiversity and relationships between plankton and global change. A CPR Atlas on the geographical distribution of plankton in the North Atlantic Ocean was first published by the Edinburgh Oceanographic Laboratory (1973). This atlas, based on about 40 000 CPR samples collected from 1958 to 1968, contributed greatly to our knowledge of the biogeography of similar to260 species or taxa in the North Atlantic Ocean. The data of the CPR Atlas were updated in the last 30 years. In this introduction to the revised CPR Atlas, which is based on data for 1958-1999, new numerical procedures and features used in preparing the updated maps are described.