Hot science for a cold past

Whale flesh composting in Aylmer

Throughout the summer, 40-year-old arctic whale flesh has been decomposing in a compost heap. The site is along a path in a forested area just north of Pink Road in Aylmer. The compost has not raised a stink, but its has attracted the attention of some of the Canadian Museum of Nature's neighbours.

“We had a bear sniff out the compost,” said Marie-Hélène Hubert, technician for the Canadian Museum of Nature's (CMN) Vertebrate Collection.

Under the supervision of Kamal Khidas, CMN’s Curator of the Vertebrate Collection, the goal of the project is to break down flesh around several jaw bones through “hot compost” enabling their study.

“Years ago, we received a collection of bones from the defunct Arctic Biological Station in Ste. Anne de Bellevue. The station closed unexpectedly and sent us many items which we are slowly opening,” explained Hubert.

“The bones in the compost were stored in vats of ethanol and we wanted to remove the eroded flesh from the bones to study them. Initially we tried boiling the bones, but it was ineffective and complicated. After conducting some research, we noticed that perhaps hot composting would be more effective because it removes much of the oil off the bones, which are rich in oil. So far, the results are good. There’s still some flesh around the bones but most of it has dried out, making it easier to remove from the bones.”

As opposed to traditional or cold composting, the soil in hot composting is much more active. Therefore, it takes less time for the organic matter to decay.

“If you reached the desired temperature of 55-65 degrees Celsius, the flesh decays much more quickly and we were looking to complete the project in three months. Unfortunately, we only managed to get the optimum temperature twice, so the composting action was not as fast as we wanted.

 

“Cold or normal compost still manages to remove some of the flesh, just at a slower pace. The temperature rises and falls with the action of the microbial flora that composts the flesh and, therefore, the more active it is, the more warmed it gets,” explained Hubert.

“For the active (hot) compost, we are working on an 18-day cycle. The first four days, we let the soil rest and then we turn it every two days, for 14 days. Then we start the cycle again,” explained Hubert. “By adding oxygen, we are airing out the compost and increasing the heat in the soil. We are not always reaching the desired temperature of 55-65 degrees Celsius for active compost, but the compost is still working. We reached the desired temperature at the end of summer. Now we have a temperature of between 30-35 degrees,” Hubert told the Bulletin as she inserted a thermometer into the soil.

The CMN team started the active compost in early June and will remove the bones from the soil before winter.

“We don’t want the bones to freeze outside in the compost so we will remove them before the ground freezes. By then, we should be able to remove any excess flesh. Afterwards, we will place the bones in ammonia because the dirt stained the bones and the ammonia will help clean them. We will then place the bones in a freezer for two weeks to remove any pest or moisture,” explained Hubert.

The bones will then be ready for examination and should be on display when the Canadian Museum of Nature opens the doors of its research and collections facility on Pink Road to the public.