The Sclero lab is moving to the Earth and Environmental Sciences department at Tulane University in Fall 2024! We will be launching some exciting new projects and seeking students at all levels. Please get in touch if interested, and check back here for more information and opportunities.

The first publication of work conducted entirely in the Sclero Lab is out today in L&O Letters. Sclero-lab alumnus Hanna Mantanona used Raman spectrometry to analyze coral skeletal cores with prominent bleaching-induced stress bands. Using the Raman data, Hanna calculated calcifying fluid saturation states before, during, and after the bleaching events. And the results were, well, surprising! Saturation state increased during the bleaching, and remained elevated afterwards. This paper will be a key contribution to the literature not because it provides all the answers (we don't fully know the mechanism behind this observation), but because it refutes existing notions in the literature and raises new questions. Way to go, Hanna!

With funding from NSF, we will be working on a 5-year project focused on advancing analysis of coral skeletal cores. This will include the creation of a virtual core repository, developing new tools for analyzing CT scans, and engaging the public in the analyses. Read more about the project here.

by Hannah Whitaker

The physical and chemical properties of a coral’s skeleton can tell us a lot about past ocean conditions; some coral species maintain environmental records that go back hundreds of years. The Sclerochronology lab has a collection of coral cores from all over the world, and this past summer, we expanded our library to include 10 new specimens from here on ‘Oahu!

​Under a permit from the Division of Aquatic Resources, our team of divers (Dr. Tom DeCarlo and graduate students Hannah Whitaker and Jess Hankins) identified and cored colonies of Porites lobata in Waimanalo Bay over the course of five dives. Lobe coral is one of three dominant coral species on the island, and its massive growth form and long-lived nature make it an excellent candidate for sclerochronology.

​The drill we use is pneumatic—powered by pressurized air—and produces cores that are 5 cm in diameter, about as big around as a water bottle. Once the core is removed, we plug the hole with cement and marine epoxy to keep bioeroders out and so that the surrounding coral has a new surface over which to grow back. Within a few months, it’s like we were never there.

Back on land, we rinse, soak, sonicate (using a high-frequency sound bath to remove debris), oven-dry, and carefully wrap each core so they can be stored for later analysis. Our longest core from Waimanalo likely dates back over a hundred years, and the lab is excited to see what history is written in these growth bands.

- by Jordyn Cotton, Sclerochronology lab Master's student

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I recently returned from a trip to the Land Down Under where I had the opportunity to get my hands dirty with field work out on the reef. Funded by the National Science Foundation, Interdisciplinary Research Experience for Students (IRES) was a three-week program to provide graduate students with field experience and expand their knowledge of coral reef science. The first week was spent in the Atherton Tablelands at the Center for Rainforest Studies about an hour southeast of Cairns, Queensland. While living in the rainforest, we learned about the connection between the land and sea and how terrestrial activities can impact the coral communities offshore. We were introduced to some of our first Australian natives: from spiders bigger than your fist to venomous snakes and massive bats. Of course, we also had to try heaps of Aussie delicacies including Vegemite, Tim Tams biscuits, and Shapes crackers. Our first guest lecturer, Michele Barnes, from the ARC Center of Excellence for Coral Reef Studies at James Cook University, gave lectures about bridging the gap between social and ecological sciences. Workshops were then held to demonstrate how creating these ties between users of a particular ecosystem are connected to one another and how these need to be addressed to implement effective management strategies. After learning about the Australian wet tropics and meeting a ton of incredible people along the way, it was time to head offshore.

The HPU Sclero lab, in collaboration with the Center for Marine Debris Research, was awarded $319,965 from the National Science Foundation to acquire a state-of-the-art Raman spectrometer. We will use the instrument for quantifying the chemistry of coral calcification, identifying the types of plastics in water and sand samples, and in teaching labs. The instrument will also be available for external users, just get in touch if you are interested in using our Raman for your research project. Among a range of features, our instrument will have multiple lasers of various wavelengths, automated 2-d and 3-d mapping, topography mapping, and the ability to process large solids and liquids.

I have drilled skeletal cores from massive coral colonies all around the world, from the Caribbean, to remote Pacific Islands, Taiwan, Australia, and Palau. Finding live corals was never very hard, there were always plenty to choose from and I would search for the largest (oldest) corals. Then, in 2019, I went to the Farasan Banks, in the southern Red Sea. I could certainly see the amazing diversity and coral cover that used to exist here. But, it's almost all dead, following a terrible bleaching event in 2015. The Red Sea is not hit by large storms or waves, so the corals are all standing dead, creating an eerie reef graveyard. I've never spent so much time just snorkeling over reefs to find live corals to drill. At some reefs, there were none. For the first time, I resorted to drilling cores from dead corals. And the live corals that I did find often had partial mortality scars.

So what happened? Why was this reef so devastated? Well, our new paper in Science Advances shows that an unusual conflux of heat and nutrients led to an exacerbated bleaching response. Initial strong monsoons in early 2015 caused strong upwelling, supplying the reef with excess nutrients. Then, in late summer, the monsoon winds suddenly died off earlier than usual, leading to anomalous heating. While a few extra nutrients might normally be good for corals, our paper shows that it is bad when combined with heat stress. The reason? I suspect that the corals' symbionts quickly soak up those nutrients and grow in size / reproduce. Then, when the heat stress comes, causing the symbiont photosystem to produce toxic oxygen species, the large symbiont populations are harmful to the coral, leading to exacerbated bleaching.