Interested in learning about fine-scale environmental variability on coral reefs? Check out this exciting new paper titled, “Patterns in Temporal Variability of Temperature, Oxygen and pH along an Environmental Gradient in a Coral Reef” that is authored by members of the Donahue and Thomas labs at HIMB. In this study, we applied spectral analysis in a novel way to characterize environmental variability in a fringing reef environment.
This collaborative paper had four outcomes: 1) we characterized fine-scale environmental variability in pH, temperature, and oxygen over a 34m reef flat to reef slope transect, 2) the spectral analysis approach allowed us to assess physicochemical processes at spatial and temporal scales that are relevant to organisms, 3) we developed a novel application of spectral analysis that allows spatial comparisons with limited instrumentation, and 4) we identified steep gradients in temporal fluctuations over a spatial-scale of only meters.
Aloha friends! We have just finished our dive ops at Pearl and Hermes Atoll. Pearl and Hermes is a rather large reef, spanning over 194,000 acres (only 80 of which are land). This expansive atoll is known for abundant reef sharks, teeming massive ulua, and of course curious monk seals. The first couple of day we had some pretty rough weather- the south side of the atoll had over 15 foot swells! But, even with the tumultuous seas in the south, the north side of the atoll was luckily much more welcoming.
The reef structures up here are so magnificently diverse! In a single day we dove on a reef dominated by Porites lobata (a mounding coral that does not offer much reef complexity) with coral canyons everywhere, a Pavona duerdeni reef (also known as the “pork chop coral”) , and a reef covered with Porites compressa (also known as the finger coral). We saw our fair share of Ulua and sharks as expected and our friend the monk seal was waiting to great us at reef 42 in literally the exact same spot as last year (click herefor last years story).
P. compressa reef
Mostly coral rubble with some P. lobata
By our fourth day here the seas subsided in the south and we were able to get to all of our bioerosion sites and conduct over a dozen coral health surveys. For an added treat, the skies completely cleared up exposing the beautiful picturesque night sky. At around 10pm there was a meteor shower with shooting stars everywhere and one meteor that completely light up the sky for maybe 3 or 4 seconds. Once again a very successful science mission to Pearl and Hermes.
Here are some Pearl and Hermes pictures for your enjoyment!
Hello again! These past few days have been CRAZY! High winds, large swells, and stormy weather, but none of that stopped this awesome team of scientists from getting their work done. Let me introduce you to the wonderful team of divers that I get to work with on this trip. Our coxswain, Tod Recicar, comes all the way out here from Gray’s Reef( a National Marine Sanctuary off the coast of Georgia). Divers Maya Walton and John Burns are fellow graduate students at the University of Hawai’i at Mānoa and they both study coral disease.
This picture basically describes our entire time at French Frigate Shoals. 🙂
On this cruise I get to work on two project. First, I am retrieving all the bioerosion blocks that I put out last year. Finding tiny blocks about the size of your fist that are now completely fouled after a year is quite a challenge. However, we found 100% all the blocks that I put out last year at French Frigate Shoals!!!! We are also assisting John Burns on a coral health survey of the islands which have been a lot of fun.
One year old bioerosion block-French Frigate Shoals Photo Credit: Maya Walton
Even on rough days, French Frigate Shoals is still a beautiful atoll filled with large table corals and lots and lots of birds. These next couple days we are transiting up all the way to Pearl and Hermes. Hopefully they will be just as successful as French Frigate Shoals!
This past year has been quite exciting! Back in May I finished my very first, year-long bioerosion experiment. Here, we were looking at how bioerosion rates change across a natural environmental gradient with in a small reef. We found some really cool preliminary data suggesting that bioerosion rates could be correlated with pH. Once all the data is analyzed and written up I will post all the fun findings on this blog.
This has also been an exciting year for coral reef research in general because this past July was the 12th International Coral Reef Symposium. This conference is held only once every four years and was attended by 2100 scientists, educators, and coral reef managers (click here to watch some inspiring talks from the conference)! Additionally, it was held in Australia–a country that I always wanted to visit. After this conference I was lucky to be able to dive on the Great Barrier Reef. This beautiful reef is one of the largest coral reef systems in the world and also one of the largest marine protected areas. Diving on this reef really showed me what reefs could look like with proper management. I have never seen so much health coral and fish in my life.
A little taste of what a healthy reef looks like…
Lastly, I need to give a little shout out the the Dr. Nancy Foster Scholarship Program. This wonderful program encourages graduate students to work in National Marine Sanctuaries (Papahanaumokuakea is one of them!) and trains students to become better science communicators. To learn more about some exciting research being conducted in marine sanctuaries all over the country and to learn about other Foster Scholars click here.
Tomorrow is our first day of dive ops at French Frigate Shoals and I can’t wait to get in the water!
Stay tuned and thanks for reading.
Hello everyone! After a year long hiatus I am back to blogging. There are lots of exciting things that have happened in the world of bioerosion over the past year and I am excited to fill you all in. I am currently out at sea again in the Papahanaumokuakea Marine National Monument (for some history about the monument see one of my previous posts here). I will do my best to fill you in on all the adventures and hopefully share some fun pictures from the field.
Thanks for reading!
Yesterday we had our last day of diving. We began each dive collecting samples for a microbial source tracking permit which was completed rather quickly. With the remaining time, we swam around and enjoyed the deep blue crystalline waters of Gardner Pinnacles. Gardner Pinnacles is a large basaltic rock that protrudes out of the water and is surrounded by boulder reefs with very high live coral cover. This atoll was a great way to say goodbye to the NWHI because it was probably one of the most beautiful coral reefs I have ever visited.
Nyssa at Gardner Pinnacles. Photo by M. Donahue
Rare corals such as Acropora humilis (the large finger-like coral in the foreground of the above photo) and Sinularia densa, a soft coral, are quite abundant on this reef. I have never seen either of these corals in the Main Hawaiian Islands.
Pocillopora meandrina heads surrounded by the soft coral Sinularia densa
Tiny red and black goatfish, chubs, large ulua, and school of curious Galapagos Sharks frequently visited us during each of our dives.
Megan and the shark
Diving within the Papahānaumokuākea Marine National Monumnet is an amazing and humbling experience. The reefs within the monument are the only reefs left that are virtually untouched by humans. I am so grateful and privileged to be allowed to conduct part my dissertation research on these pristine reefs. After spending over 48 hours underwater, diving operations for this cruise have official come to an end. The next two and a half days are spent transiting back home to Pearl Harbor. Please stay tuned for more updates on my research in the Main Hawaiian Islands. See you next year, Northwestern Hawaiian Islands!
The science team! Megan Donahue, Oscar Guadayol Roig, and Nyssa Silbiger
Nyssa Silbiger, our coxswain LTJR Adrienne Hopper, and Oscar Guadayol Roig
Laysan was our final site for the water exchange study. We had three full days at Laysan which allowed us to get a “hole” lot done. 😉 The first day we spent quite a bit of time swimming and driving around to try to find just the right spot to deploy all 4 of our instruments. We found a great little shallow spot on the back reef, allowing us to get lots of bottom time (but leaving our poor coxswain all alone for hours at a time). On our first dive we were visited by 3 rather large and curious monk seals, but none of them were aggressive (I’m still sour about number 618).
Big Monk Seal at Laysan
On our second day we had a little bit of unwanted excitement when some of our line broke underwater. Luckily, our eagle-eyed coxswain caught it immediately and saved the day (and the instruments!). Methinks the culprit was the evil looking sea cucumber sitting next to the line… or maybe it got chaffed against some near-by rock. Nobody will ever really know.
Here are some more Laysan pictures to enjoy.