Lake Tanganyika

Episode 13 – Underwater wonders: The effects of sex, heat and heavy metal on aquatic organisms


walrus-1Welcome all to the penultimate episode of the third series! Covering 71% of the earth’s surface and home to a vast array of organisms from aquatic plants to marine mammals, it is only fitting that we dedicate a podcast to exploring the wonders of the underwater world with researchers here from the University of Manchester.

dr john fitzFirstly we’ll hear from Dr John Fitzpatrick where I shall be quizzing him on his unique research looking at  postcopulatory sexual selection and the evolution of reproductive traits in marine organisms! John works on a variety of animals, from marine invertebrates all the way to marine mammals. This is due to the great magnitude and variety of sexual behaviours and modes exhibited by marine organisms. Using numerous fish species, John’s research looks to elucidate the selective forces influencing the evolution of sperm and genitalia.


Neolamprologus cylindricus: One of many cichlid fish species of Tanganyika

We discuss in particular research conducted on African cichlids from Lake Tanganyika. Various species of these cichlids engage in different mating behaviours and have adopted different mating systems over a short evolutionary timescale, providing an opportunity to see exactly how selective pressures, such as sperm competition in polygamous species, influence the evolution of reproductive traits, such as sperm morphology and male testes.

John not only looks at the evolution of male reproductive traits but also the co-evolution of female reproductive traits. This research focuses on elasmobranches and how sexual conflict between the two sexes shapes the evolution of both the female and male genitalia.

Following this, and on a slightly more serious note we shall be discussing anthropogenic factors, such as climate change with Dr Holly Shiels, and metal pollution with Dr Keith White, that are impacting both marine and freshwater ecosystems and the species that thrive within them.

HollyDr Holly Shiels research focuses primarily on cardiac physiology of ectotherms; how cardiac function is affected by factors such as temperature and dissolved oxygen availability. In our water systems, both temperature changes and changes in dissolved oxygen availability can be observed as a direct result of anthropogenic climate change. Hence this research will underpin our understanding of how fish populations will (or will not) cope with fluctuating environments. Holly uses a combination of field research, in order to assess firstly the temperatures and dissolved oxygen content already experienced by fish populations in naturally occurring water systems, and laboratory research to understand how cardiac function is affected by these factors.ribbleriver

Holly discusses her exciting new collaborative research with the Ribble River Trust, assessing whether planting riparian shade on our riverbanks can keep rivers cool and if so, are fish populations attracted to such water bodies.

dr keithLast but not least, we unearth how metal pollution enters our water systems and the responses of invertebrates to metal pollutants with Dr Keith White. Keith reveals the main sources of metal pollution, in particular acid mine drainage. Metal pollution can be particularly devastating to ecosystems, decimating fish populations and rendering water bodies uninhabitable. We find out why invertebrates are useful monitors of metal pollution and why they are so important to study due to their unique position in the food chain. We learn how invertebrates accumulate and deal with metal pollutants and finally how we can prevent or help recover polluted water systems.