In situ monitoring of eutrophication
Contents
Introduction
In situ monitoring is the observation and / or measurement of events in its original place (Latin: situs). Oceanographic instruments containing different types of sensors are used to monitor eutrophication in coastal waters. Sensors detect and respond to electrical or optical signals and convert the physical, chemical or biological parameter into a signal which can be measured electrically.
Oceanographic instruments
CTD
The CTD[1][2] - Conductivity (salinity), Temperature and Depth (pressure) recorder - is the standard oceanographic tool for continuously measurement of physical properties of sea water. The CTD is mostly attached to a frame with water-collecting Niskin bottles (CTD rosette). From the deck the rosette is lowered on a cable down to the seafloor and once in the water data are transferred via a conducting cable connecting the CTD to a computer on a ship. The Niskin bottles are closed at predefined depths to target water samples for further analysis. Other sensors to measure chemical or biological parameters such as dissolved oxygen, chlorophyll fluorescence (phytoplankton concentrations) and water light transmission can be added to the cluster.
Sensors
In this section we focus only on the sensors that measure parameters that need to be monitored in the frame of the OSPAR Eutrophication Monitoring Programme: [3]
Temperature
The simplest mechanical way to measure temperature is by using a mercury-in-glass thermometer. They are commonly used to measure sea surface temperature by placing it in a bucket of sea water. The most commonly used temperature sensors in oceanography are the electrical temperature sensors: the Resistance Temperature Detectors (RTDs) and the thermistors.
Salinity
- Phytoplankton chlorophyll-a
- Phytoplankton indicator species
- O2-concentration
- Macrophytes
- Benthic communities
- Nutrients
See also
References
- ↑ http://www.whoi.edu/instruments/viewInstrument.do?id=1003[1]
- ↑ http://noc.ac.uk/research-at-sea/nmfss/nmep/ctd[2]
- ↑ OSPAR Commission (2005), Agreement on the Eutrophication Monitoring Programme (Reference Number: 2005-4)[3]
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