Student measuring a perch (Perca sp.). She is doing this as part of a school limnology (study of fresh water) field trip, where she is learning how to

---

Student measuring a perch (Perca sp.). She is doing this as part of a school limnology (study of fresh water) field trip, where she is learning how to collect data and use it to find out about the area's ecology. Photographed in Sweden.

---

Size: 5173px × 3459px
Photo credit: © DAVID HAY JONES/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: -renewable, 2008, 21st, alberta, america, american, athabasca, bitumen, bituminous, canada, canadian, century, crude, energy, environment, environmental, fossil, fuel, fuels, hot, industrial, industry, july, land, mining, north, oil, outflow, pipe, pipeline, pollutant, pollution, pond, power, reserves, resources, rock, sand, sands, settling, slick, source, steam, steaming, tailings, tar, waste, water