“High coral cover on a mesophotic, subtropical island platform at the limits of coral reef growth”

What was the most challenging aspect of your study (can be anything from field, lab to analysis)?

The diversity of organisms colonising the shelf, the mix of tropical and temperate species, and the change in morphologies at mesophotic depths means that species-level identifications across the entire ecosystem requires engaging with a range of experts. This study was constrained to morphology-level descriptions, although future research aims to catalogue the species observed.

What was the most memorable moment in undertaking this study?

Staring out at the spectacular Balls Pyramid from the deck of the R.V. Southern Surveyor. The 552 m high rock pinnacle is a dramatic vista and it was captivating to watch the landscape change with changing light and vessel movements.

What was your favorite research site in this study and why?

The tows collected on the southern outer shelf of the Balls Pyramid platform were favourite sites as this region revealed the deepest records of coral occurrence. Tow 12CAM06 contained the deepest coral record (94 m depth) and tow 33CAM13 contained similar proportions of corals to those observed on the mid-shelf reefs. These tows also crossed over a series of drop-offs on the edge of the shelf which was impressive to watch on film.

Other than your co-authors, with whom would you like to share credit for this work?

I would particularly like to thank all the scientific and technical crew aboard the Marine National Facility R.V. Southern Surveyor (SS2013_v02). In particular for this study, tow video technicians Matthew Carey and Stephen Hodgkin from Geoscience Australia.

Any important lessons learned (through mistakes, experience or methodological advances)?

As we discovered such abundant corals in this subtropical, mesophotic region, an important lesson gained from this research is the need to explore new areas to obtain baseline datasets for the vast amount of seafloor which remains unmapped.

Can we expect any follow-up on this work?

Yes - there are a number of ongoing studies and future research planned. We have cored and dated the submerged fossil reef structure and we will be describing the age and evolution of these fossil reefs. We have also investigated the mesophotic communities around the adjoining Lord Howe Island shelf and explored spatial patterns in distributions of benthic communities across the two mesophotic shelves. Future work will be looking to the northern islands in the chain – Elizabeth and Middleton Reefs – to explore their mesophotic environments.

Featured article:

High coral cover on a mesophotic, subtropical island platform at the limits of coral reef growth | article Linklater M, Carroll AG, Hamylton SM, Jordan AR, Brooke BP, Nichol SL, Woodroffe CD (2016) Cont Shelf Res 130:34-46