Project GoldilocksLatest update August 20, 2019 Started on February 2, 2019
What depth is "just right" for coral species.
We’ve started to gear up for an upcoming fieldtrip. In mid-October we will be heading out onboard the MV Kalinda for a month long journey. We will travel the entire length of the Great Barrier Reef, visiting over 30 reefs between the Capricorn Bunker and the Torres Strait.
There are several goals of this trip, with the main mission to investigate how the history of disturbance (coral bleaching and warm water events) for each reef has effected its coral community. However, we will also be searching for new coral specimens to help clean up coral taxonomy, and searching for undiscovered species of black coral.
For my part, I will be investigating the depth distributions of different coral species at each reef. For every reef we visit, Hanaka and I will dive to the deeper areas of the reef and then slowly work our way back to the surface while conducting multiple surveys at each depth. For each survey we will photograph, record the species ID, colony size, colonial morphology (shape), and depth of 12 coral colonies. By the end of the trip we will have amassed an enormous dataset of coral depth distributions which I will use to investigate how coral communities change across depth and latitudinal gradients.
These kind of trips are rare and it is important to squeeze as much information as possible out of each reef we visit. With this in mind, I have applied for a Trident Underwater Drone through the S.E.E Initiative grant. With an onboard camera and the ability to go to 100 m, this little drone will allow me to continue to collect data in-between dives, and investigate well beyond the depths of recreational SCUBA. For example, I plan to attach one of my small temperature loggers so I can produce depth temperature profiles for each reef. Additionally the sites we will visit are incredibly remote and under studied. Who knows what we could find at these depths! Wish me luck and hopefully my application will be successful.
For more information about S.E.E. grant visit: https://openexplorer.nationalgeographic.com/initiatives/see
And for more information about the Trident ROV visit: https://www.openrov.com/products/trident/?aff=openexplorer
The images below are of a map of potential reefs we will visit on the trip, the Kalinda, and of the Trident Underwater Drone in action up in PNG through another open explorer project. Ben and Gemma are good friends, and are doing fantastic work documenting the ecology of sea mounts in Kimbe Bay. Head over to their page and give them a follow. https://openexplorer.nationalgeographic.com/expedition/pinnaclesoflife
Last week my supervisor called me into his office, saying he had a surprise for me. It turns out some equipment had been left over from an unfinished project of another researcher in the centre. Opening the box in his office, I find it full of small temperature data loggers! “I know you are going to be making your own. But, do you think these would be useful?” he asks. Uhh…YES!
While the ones I’m making will be able to record more kinds of information, I’m still months away from a working unit, and the sooner I can start recording data the better. A few days later we were out on the water heading to my local study site, and what a spectacular day it was! Calm seas, humpback whales on the boat ride out (Didn’t get a photo), spectacular visibility and good company. Importantly I now have equipment in the water generating data.
The photos below are of the boat ride out, Andrew (my supervisor) as skipper and Hanaka looking for whales, and of the temperature loggers installed in their new home.
As a part of this project, I will be conducting a long-term monitoring study at some nearby reefs. At these sites I will deploy different kinds of environmental data loggers over multiple depths to truly capture the full nature of the depth gradient.
Unfortunately, data loggers are not cheap. If you are shopping for one that can record light, temperature, salinity, and pressure you’d be hard pressed to find one for less than $5,000. Given the meagre budget of a lowly PhD student, I will have to improvise.
Recently, I attended a workshop on Innovative Technology at the Hawaiian Institute of Marine Biology. During my time there I learnt about Arduino microprocessors and the open source electronics community. Even constructing my own small submersible temperature logger. These small and cheap bits of kit have suddenly made the kind of equipment normally reserved for large institutions and government bodies attainable for the lone marine ecologist.
Currently, I’m in the building, testing, and waiting for things in the mail phase, and am not ready to start putting things in the water. However, I am excited by the progress I am making.
The photos below are of a test unit at home, and of the temperature logger I built in Hawaii.
Corals are increasingly affected by climatic disturbances, and coral reef studies are focussing more and more on investigating how corals will respond to climate change. Many of these studies explore how different coral species occupy space over latitudinal and depth gradients, because gradients represent a change in many physiologically-important environmental factors known to effects coral performance. For example, a coral species that occurs over a large depth range can presumably tolerate a greater range of light availability than a species with a narrow range. Furthermore, the peak abundance of individuals within a species range can show where the species performs best. That is, it's "Goldilocks" zone
Recent studies support this notion and have shown that most coral species are only abundant over a fraction of their depth range. This has highlighted a new question that needs investigation; why are so many corals depth specialists?
Now what is needed, is an investigation into what aspects of the biology and ecology of coral species drive these depth preferences, and if these patterns change across spatial scales, such as latitude.
To achieve this objective, this project will travel to over 20 Reefs along the length of the Great Barrier Reef to collect data on where coral species occur, and what environmental factors they occur in (e.g. light, temperature, salinity, etc.,) from 0-40 m. By investigating how species distribute themselves in relation to environmental factors, we will be able to identify what drives coral species zonation and if there is indeed an environmental "Goldilocks" zone for different coral species over latitude and depth gradients.
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