you're reading...


Coral Invasion in the Gulf of Mexico

Paper: Sammarco, P.W. et al. Population expansion of a new invasive coral species, Tubastraea micranthus, in the northern Gulf of Mexico. Marine Ecology Progress Series (2014) 495:161-173. Doi: 10.3354/meps10576


Marine and freshwater species are constantly being introduced to different parts of the world via a number of different vectors. Some species attach themselves to the hulls of ships, carrying them half way across the world, while other species hitch a ride on oil and gas platforms that are being towed to different locations. Species have even been found in the ballast water on container ships and even in other instances, aquarium hobbyists have released invasive species into the wild simply because they didn’t want them in their homes anymore. Once introduced, species distribution can become rapid and widespread.

Tubastraea micrantha

Tubastraea micrantha

The sun coral, Tubastraea coccinea, was introduced in Puerto Rico in 1943 (nobody is sure how, but chances are it was due a ship or barge transporting goods from Indo-Pacific) and is presently found all the way in the northern Gulf of Mexico. While teams were out doing survey counts on this specific coral, they found a new invasive coral species, the black sun coral Tubastraea micranthus, on gas and oil platforms. Black sun corals can thrive on highly exposed habitats (aka gas and oil platforms) competing with other benthic epifauna for space. This poses a potential threat if expansion grows dramatically. For these reasons scientists set out to estimate the current population of this new invasive coral and determine if their numbers are expanding and spreading to new locations.

The Study

Researchers chose 14 gas platforms in the Gulf (including the one with initial coral sighting) based on the location and age of the structures. Over a two year time frame the scientists were able to perform population surveys using ROVs (remote operated vehicles) that could reach depths up to 170 meters. Equipped with lights, color cameras, and laser beams to provide spatial reference, the researchers were able to survey approximately one platform a day. The ROVs filmed continuously down several vertical and horizontal transects on each platform and the imagery was later processed on image analysis software. Population densities and colony sizes of both the sun coral and the black sun coral were determined for comparison purposes.

What the researchers found

Video analysis from the ROVs revealed black sun coral populations were distributed on other platforms besides the initial one. In fact, this species was found on over half of the platforms surveyed (9 out of 14). The GI-93-C platform (initial sighting location) had the highest density and distribution was seen to decrease as you moved further from this platform (Fig. 1).

Two major ship fairways are found at the mouth of the southeast Mississippi River, which, coincidentally, is where the highest densities of the black sun coral were found. It would make sense that ships and barges traveling through the Mississippi fairway initiated the introduction of this species.

Densities of the sun coral were, as expected, much higher than those of the black sun coral. Distribution between the two species was similar, however. Population densities peaked around the platforms near the mouth of the Mississippi, and faded out the further you moved from the river’s mouth (Fig. 2).

Figure 1

Fig. 1. Density of black sun coral on 14 gas platforms. See Figure 2 for location of platforms with respect to the Mississippi River.




Figure 2

Fig. 2. Platform locations with respect to the Mississippi River. Platform GI-93C was the initial sighting of the black sun coral, directly in the middle of the shipping lane.



The highest densities of the black sun coral were found on the initial GI-93-C platform, indicating this platform in particular had a major influx of larvae from a population either on nearby platforms or on the ships coming through the channel. While greatest total density of black sun corals was found on the initial platform GI-93-C, the largest colonies were found on a nearby platform (MC-311A). This leads to the suggestion that the MC-311A platform was the form of initial colonization.

Past research has shown rapidly expanding populations are comprised of pre-reproductive organisms, followed by the reproductive organisms. This would explain why the initial sighting platform GI-93-C had the highest density, but not the highest colony size. Total density of corals is clearly biased toward smaller colony sizes.

The researchers have determined that the black sun coral has indeed successfully invaded the northern Gulf of Mexico and expansion to other regions is a definite probability. Given the fact that sun corals have expanded their population to include a huge geographic range, scientists are concerned that the black sun coral is also on its way to major expansion. If the introduced black sun coral is left unchecked for too long, the species will become integrated into its new-found community and a new community structure will take effect, changing the equilibrium of species interactions. So, watch out for the newly invasive black sun coral; it is out to find its target home!


No comments yet.

Post a Comment


  • by oceanbites 2 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 3 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 4 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 5 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 7 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 8 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 8 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 9 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 9 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 10 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 11 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 11 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com