How climate change is affecting river systems
As many of the more enlightened realise, climate change is happening at an exaggerated rate compared to previous climate fluctuations over the course of history. This change will affect just about every ecosystem that it comes into contact with, not just the globally significant areas such as reefs and rainforests.
In the UK rising temperatures and increase sea levels are going to have a major impact on the streams, rivers, lakes and other waterways that are dotted throughout our isle. Whilst these ecosystems always have their ups and downs they are among the most vulnerable to the effects of climate change because water and its distribution is a major factor in a changing climate.
During the incredibly hot summer of 2003 Britain experienced record breaking temperatures and extended sunshine hours right across Britain. This led to major increases in the temperature of our waterways which in turn caused problems with the creatures that survive there. Coldwater Salmon that swim in the streams in Scotland had to put up with river temperatures of 21 degrees which caused them to tire with many dying as a result.
Another problem for salmon, both farmed and wild occurred in 2002 when a massive bloom of the jellyfish Solmaris Corona off Western Scotland led to whole sections of open water, estuaries, river mouths and salmon cages becoming clogged, leading to suffocated fish and a much reduced population of plankton. Whilst this bloom in jellyfish is not necessarily linked to climate change it is a good indication of over fishing which allowed the jellyfish to feed off larvae and other plankton un-challenged. These mass gatherings of jellyfish are a good sign of a sea in distress.
Flooding is another major problem affecting the river systems, and in recent years there have been a wide range of different problems with flooding up and down the nation, most recently in Carlisle which destroyed many homes. Two of the three wettest winters of the 20th century occurred in 1990 and 1995, with the 21st century continuing to get warmer and wetter for us.
Flooding causes a wash of nutrients to enter the system which can be both a good and bad thing. Algal blooms can occur if too many nitrates enter the water, leading to suffocation of slow moving waterways in particular, leaving them as lifeless deserts.
Another case study is the reed beds of the UK. These generally occur in lowland marshy areas such as the fens in Norfolk, and are particularly vulnerable to climate change as increased sea levels will cause reed beds to be wiped out as tidal areas encroach inland and water salinity increases. They are a vitally important ecosystem for a wide range of plant and animal life, including one of Britain’s rarest birds, the bittern which relies on the cover of the reeds for breeding and the freshwater eel for food. Other species that are supported are a large number of amphibians which in tern provide food for Herons, Grass Snakes as well as fish such as Pike.
Whilst it is easy to think that climate change isn’t going to affect us a great deal in the UK when compared to Africa or Asia, even small shifts in climate have a dramatic impact on virtually all walks of life, with the wetlands systems of the UK being just one of them.