Date: March 26, 2020
Source: Microbiology Society
Research
published in the journal Microbiology has found that a unique type of
algae, usually only seen on the shells of turtles, affects the
surrounding microbial communities.
It
is hoped that these findings can be applied to support the conservation
of turtles. Previous research has shown that a diverse microbiome can
protect animals against infections.
The
research aimed to understand how the microbiome -- a complex community
of micro-organisms -- varies around the body of Krefft's river turtles.
Samples were assessed from inside the mouth, the top of the head and
parts of the shells of six turtles collected from Ross River in
Queensland, Australia.
The
research team, based at the University of New England and James Cook
University, then used a technique called high-throughput sequencing to
identify which micro-organisms were present on the turtles, using DNA
sequencing to determine which bacteria are present, and their abundance.
Previous
research has shown that animals in captivity often have less diverse
microbiomes, which could affect their long-term health. Dr Donald
McKnight, who led the research, said: "Successful conservation efforts
inherently require a thorough understanding of an organism's ecology,
and we are increasingly realising that microbiomes are a really
important part of host ecology. So, filling that gap in our knowledge is
important, particularly for animals like turtles.
"Turtles
are one of the most imperilled groups of animals. Nearly two-thirds of
all turtle species are either threatened or endangered, and efforts to
conserve them often involve breeding turtles in captivity or collecting
eggs from wild turtles and raising them in captivity until they are
large enough to be released. Studies on other animals have, however,
shown that captivity can alter the microbiome.”
The
results showed that the microbiome of the turtles' shells varied,
depending on whether algae was present. "It is really interesting that
even something like the presence of algae can affect the microbiome"
said Dr McKnight. "The algae on turtle's shells is fascinating. It's
actually a unique genus that grows almost exclusively on turtles.”
The
algae seen on turtles' shells has many important roles, including
providing camouflage and acting as a home for small crustaceans and
dispersing seeds. "Our study adds to those roles by showing that algae
also affects the microbiome. The mechanism through which it affects the
microbiome isn't clear yet, but there are several possibilities. For
example, it might compete with some bacteria in order to access the
turtles' shells. It may also provide a habitat for bacteria that don't
grow well on just the shell itself. Another possibility is that it could
retain moisture while turtles bask, and that could affect which species
of bacteria grow well. Our study is just an early step in understanding
turtle microbiomes, but hopefully future work will build on it and test
some of these possibilities." said Dr McKnight.
It
is important to understand what the microbiome looks like on all parts
of the turtle, according to Dr McKnight. He said, "Studies on other
animals, including humans, have often found that different parts of the
body have different microbiomes. So, it makes sense that this would be
true for turtles as well, but it is still really important to test these
things rather making assumptions
"We
don't really know how this affects the success of efforts to conserve
turtles by raising them in captivity and releasing them, but it could be
an important part of the puzzle. Our study contributes to this by
documenting the microbiomes of wild turtles, so that we have a baseline
to compare to. More studies are needed to look at whether captivity
affects microbiomes in turtles and how those shifts affect
conservation.”
Dr
McKnight hopes to continue to research turtle microbiomes: "We are in
the early stages of looking at how various environmental and demographic
factors affect turtle microbiomes. For example, we want to see if they
shift seasonally, if diet affects them, and if different ages and sexes
have different microbiomes."
Story Source:
Journal Reference:
- Donald
T. McKnight, Kyall R. Zenger, Ross A. Alford, Roger Huerlimann.
Microbiome diversity and composition varies across body areas in a
freshwater turtle. Microbiology, 2020; DOI: 10.1099/mic.0.000904