Ecosystem Tide Pools (Rock Pools)
A Tide Pool is a ecosystem in the surf and splash water zone (Supralittoral & Eulittoral zone). The main feature is the lack of a constant inflow of water. Tide Pools are supplied either by flood, splashing water or rainfall.
These pools can be found in all the Canary Islands. Some of them are artificially arranged for the guests, but the majority are natural and offer a variety of different species a home. Apart from the Canaries, rock pools are found all over the world on rocky shores.
Abiotic influence factors
While low-lying tide pools are regularly supplied with fresh water during high tide, this is done with high-lying pools only in the case of strong waves by splashing water and / or rainfall.
Apart from fresh water inflow and rainfall, there are two other abiotic environmental factors that have an influence on the happenings in the tide pool. This is wind and solar irradiation.
In the higher pools, the different species are more likely to struggle against dehydration due to sun and wind and the associated higher salt content of the water. Likewise, the salt content can be extremely low due to prolonged rainfall.
Moreover, the difference between the highest and lowest temperatures is much greater than in the open sea. During a measurement in the spring, my diving computer showed me 29°C in the tide pool, while the sea was about 19°C. In the summer, temperatures are likely to be higher. So, in a tide pool, temperature fluctuations of more than 10°C can occur within a day.
Life in lower pools is made difficult by the tidal currents. Thus, small fish and crabs must be careful not to be flushed by the current from the basin.
Generally it can be said that survival in the higher pools is more difficult because these are exposed to significantly higher fluctuations of the various factors.
For example, algae and plant plankton have an influence on the milieu in the tide pool. The photosynthesis of the algae increases with increasing sun exposure and thus increases the oxygen content of the water. This increases the PH value since oxygen is recovered via the degradation of carbonic acid. The water becomes less acid. Conversely, animals, such as fish, lower the PH value by consuming oxygen and producing carbon.
However, fluctuations in the PH value in the daytime are mainly caused by the photosynthesis of plants, which occurs only during the day.
What species can be found in tide pools?
There are a variety of species from very different orders, classes, families, and so on, that inhabit the tide pool. Among other things, we find different Anthozoa, crustaceans, plants, snails, echinoderms and also bony fish. While some of them live permanently in the rock pools, some species are only represented as young animals.
Crustacea, Anthozoa and algae, but also many blennies usually remain permanently in the basin. They are perfectly adapted to their habitat and can withstand the fluctuations of water temperature, salinity and PH value without major problems.
Examples for species in a Tide Pool
Quellen & Interessante Links
Thanks to Prof. Dr. Peter Wirtz for identifying some species.