Freelance freshwater biologist, John Davy-Bowker, uses Tinytag Aquatic 2 data loggers in a long-term river monitoring project in Dorset. With three loggers each in two chalk streams, River Frome and River Piddle, John is able to accurately collect water temperature data and compare it to external water level data and macroinvertebrate samples.
Inspired by the Environmental Change Network, with freshwater
and terrestrial sites spread out all over the UK, freelance
Freshwater Biologist John Davy-Bowker set up the
River Lab Long Term Monitoring (RLLTM) project in
Dorset. John's project focuses on two chalk streams which flow
independently and discharge into Poole Harbour: River Frome
and River Piddle. Monitoring two sites close to each other
makes it easier to see patterns from the data in relation to
temperature to determine a common denominator (i.e.,
weather) in macroinvertebrate communities.
There are always at least two Tinytag Aquatic 2 (TG-4100) temperature data
loggers in one location, with a third typically
running as a backup, to measure the temperature of the
rivers. The loggers record once every half an hour,
providing year-round data from both rivers. This temperature data
is evaluated alongside water level data and samples of
macroinvertebrates to ultimately assess what drives the
changes in stream macroinvertebrate communities through
time. Water temperature is likely an important influencing
factor in macroinvertebrate communities, which is why John monitors
this parameter so closely.
At 14 years old, the RLLTM project is still in its early stages.
The goal for the coming years is to continue to gather
high-quality data for an extended period. However, some of
the data has also contributed to other projects, such as Marsh
et al's 'Warm winters and cool springs negatively influence
recruitment of Atlantic salmon (Salmo salar L.) in a southern
England chalk stream.' Temperature data from the RLLTM
programme was used to "calculate the mean water temperature during
spawning and emergence."
It can be difficult to sustain long-term monitoring projects
using the same equipment - durability and quality are very
important. At the start of this project almost 14 years ago, many
freshwater biologists were still using traditional recorders with
probes in the water and the device to the side of the river. This
was not convenient and users often struggled to calibrate the
John instead chose Tinytag Aquatic 2 loggers because they are
robust and submersible, ideal for being underwater for a long time.
John adds, "The long battery life and robustness mean
that I can confidently leave the loggers in place for a whole year
with no concerns. I often think of them ceaselessly recoding the
river temperatures while I'm snug and warm having my Christmas
There is a convenient pillar on top of the logger to secure a
shackle or seizing wire, stopping it from coming away underwater.
There can be a lot of stress on underwater devices due to the
varying weather and river conditions, but there is no need to worry
about the Tinytag Aquatic 2 loggers being damaged, torn off, or
The RLLTM project's loggers are periodically checked to ensure
continuous recording. The convenient flashing red LED on the logger
is useful to show that the loggers are still functioning correctly
at just a glance, with a single flash every four seconds indicating
that the logger is recording. All of the Aquatic 2 loggers
involved in the programme to date have performed reliably without a
Another reason John Davy-Bowker chose Tinytag data loggers for
the River Lab Long Term Monitoring Project is due to Gemini Data
Loggers' certificated calibration service, traceable to
national standards. John comments, "the calibration
service is fantastic. We download the data every year and then send
the loggers off for calibration. We receive the loggers back with a
certificate to prove the readings, fresh batteries installed, and
new sealants, all ready to go again!"
Most of the rivers' temperature readings fall between 5°C to
15°C. John praises the off-the-shelf calibration service measuring
at points 0°C and 30°C, however, he typically uses our custom
calibration service to receive 7 points of calibration, in 5°C
increments from 0°C to 30°C, for greater confirmed accuracy. This
gives him reassurance that all of his loggers are running well and
providing the best possible data.
Impressed with the quality and durability of the loggers, John
would "highly recommend Tinytag data loggers to any
environmental scientists looking to record water temperature. They
have served me very well for 14 years and I intend to continue
using them for the foreseeable future."