CLIMATE CHANGE MONITORING SOUTH TYROL
+ 0.5 °C
Lake Kaltern/Caldaro water temperature since 2008 (average)
Lake water temperature
ImpactThe indicator shows the daily water temperature at a depth of about 1 meter in Lake Kaltern/Caldaro and Lake Antholz/Anterselva. As the average annual temperature rises, so does the water surface temperature in the lake. The shallower and smaller the lake, the more vulnerable it is to rising air temperatures.
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Background information
The water temperature at 1 meter depth depends mainly on the air temperature and water circulation. The level of the lake is also influenced by the weather: when it is warm, water evaporates and the level falls; when it rains, the level rises. Changing water temperatures and levels in a lake can affect the seasonal mixing of a lake, which in turn affects the surface temperature, but also the whole habitat in the lake. The lake system interacts with each other.
Description of the results
As a lowland lake, the average annual temperature of Lake Kaltern/Caldaro has increased significantly in recent years. Being a very shallow lake, it has less capacity to store heat and therefore tends to fluctuate more throughout the year and may be more sensitive to climate change. The highest temperature recorded in the last decade was 29.2°C on 5 August 2017. The temperature of Lake Kaltern/Caldaro has increased by about 0.5°C since 2008.
Lake Antholz/Anterselva lies at a higher sea level and is deeper. Its average daily water temperature is therefore lower. The highest temperature of the last decade was recorded in Lake Antholz/Anterselva on 5 August 2018 with 17.2 °C. Its mean average temperature decreased slightly between 2014 and 2023, which could be due to the fact that the series of measurements for this lake is quite limited.
Rising water temperatures can reduce or even limit bathing quality. Bathing can be harmful if cyanobacteria - colloquially known as blue-green algae - proliferate. Water quality and freshwater habitats are also adversely affected by warmer water temperatures. In addition, the toxicity of pollutants (e.g. heavy metals) increases, which has a negative impact on fish fauna and other freshwater species (1). Lake Kaltern/Caldaro in the lowlands is therefore more at risk than the cooler Lake Antholz/Anterselva in the mountains.
Method
The temperature of the lake is measured once an hour by means of a thermometer at a depth of about 1 meter.
Sectors affected
Health
Flora and Fauna
Biodiversity
Related indicators
Further research at Eurac Research
Current projects
CLAIMES : https://www.eurac.edu/en/institutes-centers/institute-for-alpine-environment/projects/claimes und https://www.uibk.ac.at/projects/claimes/
CHANGELAKE https://www.eurac.edu/en/institutes-centers/institute-for-alpine-environment/projects/changelake
ALPWATER https://www.eurac.edu/en/institutes-centers/institute-for-alpine-environment/projects/alpwater
Scientific presentations by Eurac Research
An integrative approach to evaluate ecosystem services of mountain lakes
Ebner M, Fontana V, Schirpke U, Pritsch H, Ohndorf M, Tappeiner U, Kurmayer R (2021)
Presentation/Speech. Conference: 12th Symposium for European Freshwater Sciences | Dublin/online | 29.7.2021 - 29.7.2021
Reference
1) Van Vliet Michelle T. H., Franssen Wietse H. P., Yearsley John R., Ludwig Fulco, Haddeland Ingjerd, Lettenmaier Dennis P., Kabat Pavel, 2013: Global river discharge and water temperature under climate change. Global Environmental Change 23:450-464 http://dx.doi.org
Contact
Eurac Research: Roberta Bottarin, Institute for Alpine Environment
Data provided by Landesagentur für Umwelt und Klimaschutz of the Autonomous Province of Bolzano, Biologisches Labor