Institute for Marine and Antarctic Studies
Climate change altering sex in the sea
Environmental conditions, like temperature and ocean chemistry, influence the development of many marine creatures in their earliest stages of life, including the ratio of male to female offspring. For example, when the temperature at sea turtle nesting beaches is warmer than usual, more female hatchlings result!
So the big question is: Will the environmental effects of climate change shift sex ratios in the future? And could this spell trouble for the future of some species?
New research has found that the green sea turtle population from the northern Great Barrier Reef has an extremely female-biased sex ratio – showing that 99.1% of juvenile, 99.8% of subadult, and 86.8% of adult-sized turtles are female. The authors state that “Great Barrier Reef green turtle rookeries have been producing primarily females for more than two decades and that the complete feminization of this population is possible in the near future.” More on this study can be found here: http://www.cell.com/current-biology/fulltext/S0960-9822(17)31539-7
Temperature isn’t always the driving force behind skewed sex ratios in the sea. Ocean acidification, which results from the uptake of carbon dioxide by our oceans, has recently been shown to affect the sex ratio of Sydney rock oysters. The researchers who undertook this study, including Associate Professor Patti Virtue from the Institute for Marine and Antarctic Studies, found that after just one reproductive cycle there were 16% more females than males when oysters were exposed to increased ocean acidification. More on this study can be found here: http://rspb.royalsocietypublishing.org/content/285/1872/20172869
Detecting range-shifting species using their environmental preferences
When I’m cold, I find myself mindlessly gravitating towards the warmth of the fireplace, while on those hot Summer days I’ll commonly seek out the comparative cool of a stream or the ocean. Moving around like this is an innate response to the temperature of the environment and, despite our ability as humans to regulate our own body temperature, suggests there’s a preferred range of temperatures that make us happiest – not too hot, not too cold, but juuust right.
Unlike us mammals, most marine species can’t regulate their own body temperature and instead rely on the temperature of their environment to do this for them – making it necessary for these species to follow their thermal preferences when environmental conditions change. When species find themselves outside the temperature range they are best suited to, it becomes difficult for them to reproduce, grow and feed, which results in poor competitive ability and sometimes death.
So… marine species have strong preferences for specific environmental conditions, like a preferred temperature range. But how can we apply this understanding for assessing the ecological effects of climate change in marine systems?
Well, we know that climate change is driving a rapid, global redistribution of biodiversity, and these changes are occurring fastest in marine systems (https://theconversation.com/climate-driven-species-on-the-move-are-changing-almost-everything-74752). However, it’s very difficult to detect these changes for many marine animals because historical data sets of species occurrence locations seldom exist, and when these are available the information they contain is usually highly confounded by observer biases. For example, observations of animals commonly come from locations that are easy for people to access, and may not actually represent the true range of a species.
In the absence of these high-quality data sources, we can instead turn to our understanding of species environmental preferences to infer potential changes in their distributions through time. It’s important that multiple environmental factors, and not just temperature alone, are considered when assessing the combination of conditions that different species are best suited to. Thankfully, satellite technology now allows us to remotely sense lots of environmental variables, such as sea surface temperature, dissolved oxygen and current speed. This information can be matched to the locations where a species of interest has been recorded in order to gain a thorough understanding of the overall environmental conditions that species prefers.
Understanding the combination of environmental conditions that best describe where a species has been observed helps us predict the chance of that species occurring in other locations, given some information about the environmental conditions of those locations (again, easily available from satellites). If these predictions are made regularly and over a long period of time (say, each month for 20 years), it’s possible to measure changes in the area that species are likely to be found. It’s also possible to account for the influence of natural climate variation on these predictions (like seasonal warming and cooling), and doing so can help reveal the underlying influence of human-caused climate change on species distributions.
While you might not consider your next drive to the beach on a hot Summer’s day an attempt to ‘track your thermal preference,’ it is worth considering that the location of species’ in space and time is highly dependent on preferences for environmental conditions that they have acquired through the course of evolution. Worth considering also, are the many useful applications for this understanding of species selecting for their preferred environmental conditions - like for predicting the ecological effects of climate change, or for justifying why you’re at the beach on a hot day when you should be at work.
Redmap Diver Photo Competition: ENTER NOW
The Redmap Diver Photo Comp is a celebration of the strange critters and wonderful moments enjoyed by divers - from being up close and personal with unique marine life, to marvelling at the entirety of a marine community. It’s too common nowadays that our photographic efforts only result in space taken up on our hard drives, rarely seeing the light of day they deserve. With Summer now behind us, our Diver Photo Comp is a great opportunity to share recent diving adventures or dig up old ones to relive and celebrate.
The Redmap Team invites divers to submit their favourite photos to one, or all, of our three great categories, with generous prizes on offer. In each category prizes will be awarded to the winners of the People's Choice Award and Redmap's Choice Award – that’s a total of six prizes up for grabs!
Entries close: 9 pm Sunday 21 May
Online voting period: 9 am Monday 22 May – 9 pm Sunday 4 June
Winners announced: Monday 5 June
1. Up close and personal
Coming face-to-face with marine life, whether it’s large or tiny, is always a treat and often ‘other-worldly’ - submit your best close-up photo of marine life.
2. A unique encounter
Some species are more exciting to see than others. It’s likely that these are the critters we don’t see on most dives, so when we do it’s a real treat - submit your favourite photo of a unique encounter with marine life.
While individual animals darting in front of us can easily grab attention, they are only parts of larger, diverse communities of marine life - submit your best photo of underwater communities, from coral reefs to temperate kelp forests.
How to enter
Attach your photo(s) to an email and send it to: firstname.lastname@example.org
Include in your email:
1) your name, and
2) a title for your photograph
3) a caption to tell us a little about the photograph.
You will be notified that we have received your submission, and also informed of the competition’s results, via return email to the address from which you submitted your entry.
NB: Redmap Australia will NOT disclose your email address during or after this competition.
Two great prizes are up for grabs in each category. One will be awarded to the winner of the People's Choice Award and the other awarded to the winner of the Redmap's Choice Award.
People's Choice Award – $200 gift card at either Boating Camping Fishing OR Bunnings Warehouse (the choice is yours).
Redmap's Choice Award – A comprehensive field guide to the Tropical Marine Fishes of Australia.
People’s Choice Award
Voting for the People Choice Award will take place on Redmap Australia's Facebook page - https://www.facebook.com/RedmapAustralia. Within each category, the photo with the highest number of ‘likes’ during the voting period will be deemed the People’s Choice Award winner. We encourage you to follow the competition on Redmap Australia’s Facebook page, and to ‘like’ and ‘share’ your favourite photos.
Redmaps’s Choice Award
Members of the Redmap Team will vote on their favourite photo in each category, with particular attention given to the creativity of the title and caption that accompanies each image.
Conditions of entry
1. Entrants can submit a maximum of two photographs to each category.
2. By entering your photo to this competition, you give Redmap Australia permission to post your photograph, accompanied by your name, photo title and caption, to its Facebook page, Twitter account and website.
3. Redmap Australia reserves the right to edit the title or caption of your image to ensure it is suitable for public viewing (please keep it family friendly).
4. Only photos of live animals in their environment will be allowed entry into this competition. Redmap Australia values the contribution of recreational fishers highly, as shown during our 2016 Redmap Fisher Photo Comp. However, this specific competition is aimed at the diving community, so we ask that no fishing photos are entered this time around (but underwater photos taken by spearfishers of live fish are warmly welcomed).
WA coral reefs threatened by climate change
Check out this short video and information on WA's coral reefs: HERE
We're experiencing some MAP errors at the moment (when logging a sighting or viewing a species distribution).
We are really sorry about that - it's beyond our control and we're hoping to have it fixed as soon as possible!
Thanks for your understanding!
QLD study: fish behaving badly on acid
Photo: fish swimming amongst natural carbon dioxide bubbles in research conducted off the coast of PNG (James Cook University)
Redmap's "other species" sighting category
The Redmap list is generated using a number of factors, including the ability to easily identify a species from similar species, which is often not possible just by looking at it! Redmap’s species list also needs to be limited so that we can get people to focus their efforts on marine life that scientists believe are likely to move (or for which there is already information confirming their movements).
So the idea of ‘other species’ is to allow people to send in sightings of species that we have not specifically listed – but which they think are unusual to the area (this may take a little research yourself!). In time, some of the ‘other species’ logged may end up providing enough evidence that we then start including them to watch out for! One of the greatest advantages of using citizen scientists is that they’re often on and under the water more than scientists – and see things happen long before they are scientifically surveyed. It’s this important information that Redmap is able to capture with your help.
When logging ‘other species’ please remember that it’s not just an identification service – our scientists all volunteer their time, so it’s important that you do a little research yourself first. Check out our species pages.
Redmap newsletter Dec 2013
Read the December 2013 newsletter here!