Remote instrument packages typically use Valeport 606+, Seabird SBE19 or YSI 6600 EDS multi-parameter sondes. These instruments have sensors for the measurement of salinity, pressure, temperature, dissolved oxygen, turbidity and chlorophyll a fluorescence, not every parameter is measured at every station.
High temporal resolution data is gathered to help understand and monitor the environment. For example, monitoring the oxygen status and algal content of the water body can help to define algal blooms and understand their effects alongside the cycling of organic and inorganic matter. Data relating to diurnal, seasonal and episodic events can then be related to physical and chemical conditions within the water body to facilitate management and monitoring.
Deployed instruments are moored beneath the only visible part of the system, either a buoy that supports the antenna spar and solar arrays or a navigation platform. The instrument package is deployed beneath the buoy and securely anchored to the bottom. In certain sites, a combination of instruments at two different depths allows processes such as stratification and its effect on water quality to be studied.
A McLane Remote Access Sampler (RAS) is currently deployed in combination with a Seabird SBE 19 CTD (with additional fluorimetry and turbidity) on the Belfast Lough Mooring Package. The sampler is capable of taking up to 48 individual 100-ml samples over extended time periods, and preserving them for future analysis. Full GSM communication and control allows flexible sampling schedules. This system is self-cleaning, logging facilities record the details of each sampling event. Current developments include the software integration of instruments through a multiplexed system, allowing autonomous control and integration of instrumental, water sampling (RAS) and Meteorological packages.
Configuration
Moorings contain GSM modems allowing communications with the remote instruments from a base station – this provides near-real-time data on water quality and instrument function on demand. Power supplies for the instruments and communications are self-contained and are sufficient for long deployment in aquatic environments. Service intervals are determined primarily by biofouling and instrumental drift.
Data Telemetry
Data is transmitted to a base station at pre-determined intervals. In addition, all collected data are stored on internal memory units for analysis post-deployment. The nature of the relayed data and the frequency of sampling and transmission can be configured to suit the site and application. Data will be made immediately available on this website to all interested agencies, individuals and the public.
Application
Water quality parameters and physical processes such as stratification can be identified and monitored allowing better reactive management and monitoring. The high-resolution data allows the temporal stability of physico-chemical parameters to be monitored. The interaction between different water bodies can be investigated, aiding early warning of algal bloom events, better modelling of water stratification, and direct monitoring of water quality.
Quality Assurance
Recent investment in new dedicated reference instrumentation is being coupled to improved data management of referencing measurements allowing for more objective data quality control. It is our current goal to establish a system that can report (in a semi-automated or automated manner) data within defined quality limits or perform exclusions if reference measurements don’t comply with filtering criteria. Whilst some un-validated (but still good quality) data could potentially not be reported due to this process, all data is retained so that both non-QA’d and QA’d data can be reviewed and interpreted. We anticipate the web-hosted data to offer quality assured outputs in addition to the near-real time data in the near future.