WTT Blog - Tagged with stable isotopes

MSc Research with WTT

Posted on May 23, 2018

MSc Research with WTT

I’ve just had the pleasure of hosting two MSc students from Queen Mary University of London (co-supervised with Dr Chris Eizaguirre), partly for the WTT Annual Get Together, and partly to undertake some fieldwork specifically for Charlotte Pike’s project. I alluded to their research projects in a former post and now I have the pleasure of handing over to them to update you.

Charlotte’s project focuses on the use of stable isotopes to determine the success of river restoration. I will be analysing samples from pre and post intervention works against an unimpacted control site on the same river to see how the restoration has affected the ‘architecture’ of the food web. Hopefully it should be more like the control! The intervention works have been carried out by the Ribble Rivers Trust at two locations; Bashall Brook and Towneley Hall. At Bashall Brook, a riparian zone has been created where banks of the river were previously bare; essentially livestock exclusion fencing now removes the impacts of grazing and poaching. This strip of vegetation acts as a buffer to reduce nutrient run-off from farmland, keeps the ground more stable and resilient to flood damage to reduce soil erosion, and provides necessary refuge for wildlife. At Towneley Hall, a partial weir removal and a rock pass re-instates the connectivity of the River Calder allowing fish to move between formerly fragmented habitats. These interventions have been conducted to improve the quality of the habitat at these two sites, and it’s my job to find out what changes have occurred as a result! 

Land and lake interconnectedness

Posted on March 30, 2017

Land and lake interconnectedness

On a day-to-day basis, most of my time as WTT Research & Conservation Officer is devoted to river habitats, but in my academic role at the Lancaster Environment Centre, lakes are a long-standing focus of my aquatic ecology research. A Natural Environment Research Council grant allowed a colleague from Cambridge and I to convene a workshop with scientists from Canada, the USA and Sweden, with common interests in how lake food webs may be fuelled by subsidies from the land. The output from that meeting is a recently published synthesis based upon data from ~150 northern lakes. Most of the planet's freshwater lakes and rivers that we associate with various ecosystem services, like fisheries and water supply, are found in the northern hemisphere, a region that is changing rapidly in response to human activity intertwined with shifting climatic trends.

The classical view of lake food webs is that of algae produced via photosynthesis forming the food base for zooplankton (such as water fleas or Daphnia) that is then munched by fish. We do not contest this because algae are typically a very high quality diet, and many lakes contain plentiful algae. However, in lakes that do not contain adequate supplies of such a resource, or during winter when it is less available or completely unavailable, then organic matter from the land, derived from the breakdown of terrestrial plants, can still be used via intermediary bacteria. And this situation is more common than you might imagine.