Freshwater Ecosystems Operating in a Changing Environment

“Simplicity on the other side of complexity: understanding how natural ecosystems operate in a changing environment”

Professor Guy Woodward

This seminar began in a promising fashion – how freshwater ecosystems are changing or adapting in a changing environment; learning how ecosystems can bounce back after an algal bloom and how temperature can cause huge differences in aquatic populations. Unfortunately, the actual seminar was more focused on “what eats what” and other food chains.

The talk was mainly focused around the Brown Trout (Salmo trutta) and the effects of changing temperatures on their feeding habits. By finding the thermal limits of organisms we can speculate which organisms will be able to survive at the predicted temperatures.

Algal blooms

When algae overgrows and takes over bodies of water we refer to them as algal blooms. The algae can cause mass animal deaths as a result of low oxygen levels in the water (Hypoxic conditions). When the algae dies, microorganisms decompose the algae and remove even more oxygen from the water.

These blooms are more common and are much more detrimental in warmer streams where algae can grow faster and thicker than in colder waters.

Brurafoss, Iceland 

In Iceland

There are streams and rivers which originate at the same lake and follow the same path yet differ in temperature. By comparing the species which survive and thrive in these streams modelling data can be collected and applied to ecosystems around the world.


“Warming is widely predicted to cause reductions in mean food chain length”

My thoughts:

Overall this talk was more dull than interestig. Professor Woodward’s research is fascinating, but, it is a shame that the focus of the talk was on the fish species and their foodwebs. As for how this talk will affect my career choices, I am more interested in the diversity of species (which were glossed over) and how they will cope (or not) in these changing environments opposed to the food chain of the brown trout.


This is the part of the blog where I reflect on the seminar and talk about how this will affect me, my future, and career plans.

As I said earlier, the idea of the talk greatly interests me and I would love to work in freshwater conservation. It has given me an insight into what ecological studies I could do in the near future and how I could structure my research.


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