Micromolar nutrient concentration profiles from CTD Niskin bottles sampled at the long term time series at Station L4 in the Western English Channel from 2000 to 2019.

Results are reported for the analysis of water samples taken from the L4 long-term sampling station (50°15.0'N;04°13.0'W) situated off the southwest coast of England, United Kingdom. The analyses are reported for Nitrate+Nitrite, Nitrite, Silicate and Phosphate concentrations, for samples that are both filtered and unfiltered. The dataset begins in 2000 and runs through to 2019. Since 2007 the site visits have been on a more regular almost weekly sampling protocol. A classical picture is seen of generally summer nutrient depletion and with higher winter concentrations of Nitrate, Silicate and Phosphate, however particularly in wet summers like 2012 there is a big influence of the River Tamar and spikes of high nutrient loads are seen being introduced into this nearshore sampling site.