Corals are typically linked in people's minds to tropical locations, yet the Falkland Islands harbor a surprising wealth of cold water coral diversity, notably within the Stylasteridae (lace) coral family. Recently, Dr. Narissa Bax shared insights from her collaborative research on these corals from the Burdwood Bank and Bird Island at the 8th International Deep Sea Coral Symposium in Edinburgh, Scotland. Concurrently, she led a workshop to aid in the development of global metrics to understand these corals in a rapidly changing world.
This article provides an overview of some known species from the South West Atlantic, hinting at the potential findings that await future exploration. The abundant biodiversity of the Falkland Islands' corals underlines the importance of supporting scientific research and discovery. We extend our thanks to the Schmidt Ocean Coalition and the Deep Ocean Observing Strategy (DOOS) for their financial support, enabling Dr. Bax to travel to Scotland, and to the scientists and attendees of the coral symposium, who persist in unraveling the enigmas of deep-sea corals world-wide.
Stylasteridae (lace) corals of the Falkland Islands
Living and working in the Falkland Islands, we are surrounded by rugged beauty above the waves, yet it is beneath the sea surface where some of our most extraordinary residents thrive. Today, I invite you into the enchanting realm of the coral family Stylasteridae, or lace corals.
Lace corals belong to a group of animals known as hydrozoan cnidarians. This might sound complex, but let's break it down into simpler terms. Cnidaria is a group that includes creatures you might be more familiar with, like jellyfish and sea anemones. They all share a few common features like tentacles with tiny stinging cells (used for catching food), and a simple body design that's basically a sac with a single opening.
Hydrozoa, a class under the phylum Cnidaria, encompasses creatures such as the Portuguese Man o' War. Typically, hydrozoans exist in colonies, akin to how bees live in hives. Within these colonies, each individual hydrozoan has a specific role to play, much like the division of labor seen in bee communities. However, these colonies are normally sessile, meaning they are permanently affixed to a spot and do not roam freely.
Now, the lace corals are unique as hydrozoans because they build hard, mineral skeletons, which is a trait more commonly associated with 'true' corals (in the class Anthozoa). These skeletons are what give lace corals their intricate, lace-like structures. Each tiny hole in the skeleton is a home for an individual hydrozoan animal, all living together in a colony - like a neighborhood of tiny jellyfish-like creatures, all housed together in a beautiful, hard-built, lacey high-rise!
My PhD on Stylasteridae corals gave me an in depth understanding of these stunning creatures, supported by the wealth of resources at the Smithsonian Natural History Museum. The images I share today were collected as reference material, but after years of study on these corals, I recognise each species like an old friend when I see them in the SAERI and fisheries specimen and image collections. And, occasionally, I stumble upon these corals unexpectedly adorning local gardens and homes, adding a distinct charm to these spaces. These instances, possibly remnants of a past era, are bittersweet reminders of a time when corals were appreciated differently - as unique mementos brought back by fishing families. Despite their undeniable beauty, as a scientist, I feel a twinge of melancholy at this sight, with concern over the implications of such practices. It is vital to remember that these stunning organisms are not merely decorative items, but intricate living systems crucial to our planet's health. Therefore, while we can admire their aesthetic value, we should refrain from encouraging practices that may inadvertently harm their vital ecosystems.
The South West Atlantic waters are a hotbed of unique biodiversity and I am thrilled to share with you a glimpse into the mesmerising world of these lace corals, their intricate structures, much like an underwater tapestry - these are just some of the species living on the seafloor in the Falklands Conservation Zone:
Having introduced you to some of the intricate coral species, it is time to take our exploration from the individual creatures to the vibrant habitats where they thrive in the Falklands Conservation Zone, and the locations I presented on at the recent coral symposium in Scotland:
Research case study location: Burdwood Bank
The Burdwood Bank, a submerged plateau south of the Falkland Islands, teems with marine life. This underwater oasis, rich in essential nutrients, serves as a veritable 'supermarket' for a myriad of marine species. From whales and seabirds to various fish, it's a crucial feeding ground where our ocean's favorite inhabitants gather to dine. Recent evidence shows that it's not just the bigger animals that benefit from this productive region; the animals that live on the seafloor - the benthic (bottom dwelling) deep-sea species, like corals - are thriving too.
Among these are the now familiar Stylasterid (lace) corals, and our studies in 2018 and 2019 found these corals in abundance, along with several other coral and sponge species. What's interesting is that these organisms are great at capturing and storing CO2, making them crucial players in seafloor blue carbon research (Bax et al. 2021). Yet, we need more information to make sure we can measure this accurately (Bax et al. 2022). Our recent surveys are helping us understand how much CO2 these underwater communities can store and the potential they hold in slowing down climate change.
Read more about life on the seafloor on the Burdwood Bank here: Beautiful Biodiversity on the Seafloor_March 2022
Identification is a fundamental first step, from which our work can extend to understanding the response of this region to ocean acidification, the ongoing decrease in the pH of the Earth's oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere, which results in the seas becoming more acidic, and other facets of climate change such as ocean warming. We are keen to delve into the age and mineralogy of coral skeletons to understand their response to change over time, especially for Errina corals, which intriguingly utilise a bimineralogy comprising both calcite and aragonite. This characteristic might hint at an unexpected resilience in these corals, potentially equipping them better against environmental stresses - a strategy that may have seen these corals colonise and proliferate in select habitats, like Bird Island, during the last glacial maximum over 20,000 years ago.
Image left: Dense aggregations of Errina laterorifa and Errina fissurata, with E. gracilis and Inferiolabiata labiata also noted in East Antarctica © Australian Antarctic Division, for comparison see the video footage of Errina sp. corals at Bird Island here: MMA Bird Island Coral Gardens
Image right: Errina laterorifa from the Scotia Arc © Narissa Bax