NOTES ON QUALITY CONTROL:

Dissolved oxygen loggers require calibration prior to deployment and are checked for drift after retrieval (though drift isn't anticipated given optical sensor technology).

In the event that dissolved oxygen loggers weren't cleared at a frequency sufficient to prevent data errors from occurring these data are removed prior to analysis.

Additionally data must be scrubbed of erroneous measurements which are relatively rare and very apparent. An error code of -888.88 is the primary error for dissolved oxygen loggers. Salinity probes rarely provide erroneous data and when they do it is typically the result of fouling.

PHYSICAL SAMPLE DETAILS:

Water is sampled bi-weekly to monthly using a Niskin water sampler at a depth of 0.5 m from the water surface, from May-November.

Samples are processed in the laboratory in duplicate for chlorophyll a and seston within ~8 hours of being collected.

SAMPLING METHODS:

For each study estuary, dissolved oxygen is monitored continuously with optical dissolved oxygen loggers in the upper and mid-estuary. Tidal amplitude and salinity (NB and NS only) were also monitored at the upper estuary location only. Depth profiles for other water quality variables are taken at the bi-weekly or monthly scale as well as samples for seston (NB and NS only) and chlorophyll a (a proxy for phytoplankton). These parameters are monitored on a 3 year cycle except for two sites in PE and one site in NB and NS which are monitored annually: West and Wheatley, PE, Cocagne, NB and Pugwash, NS, respectively.

Data is collected for eelgrass coverage by a collaborator between June-September, ideally during the same year we collect water quality data.

Collaborators include the province of PEI’s Department of Environment, Water and Climate Change and the Southern Gulf of St. Lawrence Coalition on Sustainability.

CITATION LIST:

Michael R.S. Coffin, Simon C. Courtenay, Christina C. Pater, Michael R. van den Heuvel. 2018. An empirical model using dissolved oxygen as an indicator for eutrophication at a regional scale. Marine Pollution Bulletin Volume 133.

Michael R. van den Heuvel, Jesse K. Hitchcock, Michael R.S. Coffin, Christina C. Pater, Simon C. Courtenay. 2019. Inorganic nitrogen has a dominant impact on estuarine eelgrass distribution in the Southern Gulf of St. Lawrence, Canada. Limnology and Oceanography Volume 64 Issue 6.