“Whales” and
“microbiology” aren’t two words you often hear in the same sentence, however, like
most animals on earth, microbes play a key role in their existence. This study
looks at the microbiome found within the blow of humpback whales (Megaptera novaeagiliae) and how this may
provide an insight into the health of the individual whales as well as other
species.
Numerous
large whale populations worldwide are currently listed as critically endangered,
to know how to best conserve these populations it is key to investigate how
anthropogenic factors impact cetacean’s health. Due to the size and the nature
of these animals, monitoring their health is no easy feat, therefore previous
studies tend to focus on dead, beached or captive individuals. Like human breath,
the blow is an exhalation from the pulmonary system, which could be home to a
core microbiome as well as pathogens.
The
experiment was done using a sterilized drone, this would hover 2-4 m above the
whales blow and using mounted PCR plates collect samples from the blow. The
previous method for this was using a boat and a long pole to collect the blow
samples but drones provide a less intrusive and safer method for both the whale
and the researcher. The samples were collected in 2 locations: Race point-cape
cod, Massachusetts and around Vancouver Island, British Colombia. The samples
from the blow were compared to air samples taken using the same method, as well
as sea water samples all in the same area; this was to determine if the blow
microbiome was significantly different to the surroundings.
After sequencing and comparing partial small subunits of the
rRNA of bacteria and archaea it was shown that blow microbiomes were 50-90%
similar between individuals and between the different sample sites, but these
microbes were significantly different to the seawater. The humpback blow contained
diverse assemblages of both abundance and phylogeny of archaea and bacteria
(eukaryotic genes were not tested for). 26 OTU’s were present across all
humpback whale blows with 25 of these considered to make up the core pulmonary
microbiome. Most of these, when compared to genetic data bases, were like those
found in other species of marine mammal; such as the mouth and blow hole of a Bottlenose
dolphin (Turpsiops truncates).
This study offers a new less intrusive way of sampling, as
well as finding evidence for a core pulmonary microbiome between healthy individuals
and species. However, this method needs significant improvement as the drone
can only provide low volume samples, increasing risk of contamination. Additionally,
they only tested “healthy” whales, therefore an interesting further point of
study would be to characterise the microbiome of an un-healthy whale. This
study provides plentiful opportunities for future studies as well as a baseline
understanding of the bacterial and archaeal composition of a whales blow which
may also prove useful and comparable across numerous cetacean species. It’s
also an exciting new insight into whale health and the use of technology to
further our understanding of a fairly under researched area.
Bibliography
Apprill, A., Miller, C., Moore, M., Durban, J., Fearnbach, H., & Barrett-Lennard, L. (2017). Extensive Core Microbiome in Drone-Captured Whale Blow Supports a Framework for Health Monitoring. Msystems, 2(5), e00119-17. http://dx.doi.org/10.1128/msystems.00119-17
Hi Pippa,
ReplyDeleteWhat a novel and exciting study - thank you for sharing this with us!
I was wondering if you knew or if the authors had mentioned of any future expansion to this study? It seems there is a lot of potential for further research of this topic. It would be interesting if they could compare the microbiomes of "healthy" vs. "unhealthy" whales as this might provide some insight into the function of the associated microbiome for their health. Also, it would be interesting to see the comparison between other species of cetacean.
Many thanks,
Sophie
Hi Sophie,
ReplyDeletePleased you enjoyed this study as much as I did. As you pointed out this is a very novel study and so the authors do suggest numerous points for further study as well as improvements for the one they have done. Regarding the "healthy" vs. "unhealthy" whale blows this is discussed a fair bit in the paper as it will be necessary to compare the two to truly understand if the core microbiome does change due to state of health. However, the authors then discuss the difficulties of identifying and testing this in the wild. In an ideal world they would test a whale with a pulmonary condition however this is difficult to identify and so a condition identifiable by drone surveillance such as poor body condition is a more likely option for future study in “healthy" vs. "unhealthy" blow in determining if blow changes with health.
Again, due to the novel nature of this data there is only one truly comparable study which is of the microbiome found in the blowhole of a Bottlenose dolphin. This data was on par in richness and diversity as well as sequence homology as that of the humpbacks blow which supports the possibility of a core microbiome across species. But again, more study is needed in this field.
Further work based on this study will also need to consider the limitations of the sample methods. The use of the drone in this study although proven to be less obtrusive and safer often provided low volume samples which are more prone to contamination. In linking to this, in this study only Bacteria and Archaea were looked at but to get an overall picture of health you would also need to consider Viruses and Fungi. However, this was not possible in this study due to the low quantity sample methods and so if there was to be further work from this study the methods would need to be assessed the opportunity as well to identify the fungi in viruses that may be present.
A final point of study mentioned was the possibility of using this methodology on smaller cetaceans, however the ability to operate the drones safely and unobtrusively around small cetaceans is till being examined but could in future provide an interesting point for study.
Thanks again for reading and I hope this answered all your questions.
Regards,
Pippa
Hi Pippa,
ReplyDeleteI really enjoyed reading this, I was just wondering if you could tell me a bit more about the differences in the microbiomes between the sites. You say there is a 50-90% similarity between individuals and the sites but did the authors suggest site had a significant effect on the core microbiome? It would be interesting to find out, especially as they are such transient animals!
Many thanks,
Amelia
Hi Amelia,
ReplyDeleteI am pleased you enjoyed reading this , I think its such an exciting and novel study!
In answer to your questions , the authors do state that the samples collected from Cape Cod were significantly different from those at Vancouver island. However unfortunately they don’t suggest why or look into this in more detail.
They do suggest that the core microbiome makes up 36% of the blow biome which is a particularly high figure considering the samples were taken from populations residing in distinct ocean basins. The only other suggestion of variation between sites is that the sample numbers varied between sites with 17 whales being sampled at Cape cod but with no repeats where as at Vancouver Island 9 whales were initially sampled followed by 8 repeats. So although total samples were the same at 17 the difference in sampling could possibly have had an effect on the results however this is not discussed further.
Unfortunately this is all the paper says about the variation between sites,so I'm sorry I cant answer your questions with more detail. However I do think this highlights an area for future study and could have numerous avenues to explore.
Thanks again for reading,
Pippa
Thank you for your reply, I agree it would be an interesting area for future research!
DeleteAmelia