Station L4 is located in the English Channel, 10 nautical miles south-west of Plymouth, UK. ( 50.25N, 04.22W).

Ammonium and ammonia concentration parameters in water bodies; Air pressure; Air temperature; Atmospheric humidity; Variable fluorescence parameters; Electrical conductivity of the water column; Particulate total and organic carbon concentrations in the water column; Chlorophyll pigment concentrations in water bodies; Dissolved oxygen parameters in the water column; Wind strength and direction; Raw fluorometer output; Particulate total and organic nitrogen concentrations in the water column; Optical backscatter; Light absorption in the water column; Salinity of the water column; Ocean colour and earth-leaving visible waveband spectral radiation; Dissolved concentration parameters for other gases in the water column; Density of the water column; Temperature of the water column; Raw suspended particulate material concentration sensor output; Urea concentration parameters in the water column; Zooplankton taxonomy-related abundance per unit volume of the water column; Zooplankton taxonomy-related biomass expressed as carbon per unit volume of the water column; Phaeopigment concentrations in the water column; Concentration of suspended particulate material in the water column; Nitrite concentration parameters in the water column; Solar Radiation; Concentration of alkanes in the water column; Sound velocity and travel time in the water column; Visible waveband radiance and irradiance measurements in the atmosphere; Visible waveband radiance and irradiance measurements in the water column; Zooplankton egg hatch proportion; Phytoplankton taxonomic abundance in water bodies; Transmittance and attenuance of the water column; Concentration of other organic contaminants in the atmosphere; Silicate concentration parameters in the water column; Raw light meter output; Bathymetry and Elevation; Carotenoid and flavenoid pigment concentrations in water bodies; Phytoplankton taxonomic biomass in water bodies; Dissolved total or organic phosphorus concentration in the water column

Fluorometers; radiometers; optical backscatter sensors; water temperature sensor; plankton nets; discrete water samplers; salinity sensor; water pressure sensors; transmissometers; CTD; dissolved gas sensors

The data set comprises measurement of physical and biological oceanographic parameters from the Western English Channel, initially collected as part of the Plankton Monitoring Programme at Station L4 from 1988 onwards. L4 is one of a series of hydrographic stations in the Western English Channel which have also been the basis of a series of hydrographic surveys carried out during the 20th Century by scientists at the Marine Biological Association in Plymouth. In May 2002 sampling expanded to include Station E1, approximately 25 nautical miles south-west of Plymouth. Plankton Monitoring began through the work of the Plymouth Marine Laboratory (PML) Zooplankton Group. Other stations include Rame head, Jennycliff, Plmouth Deep and Cawsand. A long-term time-series of weekly observations has been established by exploiting the activities of small boats (Sepia, Squilla and Plymouth Quest) in an opportunistic way as by-product of their other sampling activities, for example the collection of live plankton, sea-water, trawling for fish and squid. Initially no formal research programme or long-term funding for the Plankton Monitoring existed but the series was included in NERC Oceans 2025 funding as a Sustained Observatory and continues to be funded under NERC National Capability. Funding has been provided over different time periods under various names but the programme is commonly referred to as the Western Channel Observatory (WCO), with additional funding allowing additional data collection to take place, taking advantage of the core measurements. Although every attempt has been made to standardise methodology and achieve data consistency it is important to recognize that the varied personnel and research objectives that have contributed to this dataset may impact on the nature of the data set. The core datasets are made available through the westernchannelobservatory.org website. Data are also submitted to BODC where it is archived and published with a DOI at finer granules. At BODC further meta(data) checks take place and metadata are enriched and served through BODC systems with PML originators informed of any changes to data.

Plymouth Marine Laboratory
Prospect Place The Hoe
Plymouth
England
PL1 3DH
United Kingdom