you're reading...


With A Little Help From My Friend: Unexpected benefits of invasive species?

Olabarria, C., Gestoso, L., Lima, F. P., Vázquez, E., Comeau, L. A., Gomes, F., … Babarro, J. M. F. (2016). Response of two mytilids to a heatwave: The complex interplay of physiology, behaviour and ecological interactions. PLoS ONE, 11(10), e0164330. doi:10.1371/journal.pone.0164330


Invasive species are often touted as being destructive to environments; they barge in uninvited, set up shop, and often thrive to the detriment of other organisms. As with most “problems” though, subtle and unexpected interactions can often be overlooked. This is exactly what could be playing out between two species of mussel off the coast of Spain.

Mussel bed in an intertidal zone during low tide. Photo by Ian Sutton, 2009.

Mussel bed in an intertidal zone during low tide. Photo by Ian Sutton, 2009.

Mussels live in the intertidal zone—an extreme environment where inhabitants have to cope with large temperature fluctuations, desiccation (water loss), and variable salinity, among other physiological challenges. For colonial organisms like mussels, living in close quarters adds another complication to overcoming these challenges. At the center of an aggregate, temperatures can spike beyond lethal limits, nutrients can be limited due to uptake by the animals on the outskirts, and local water chemistries can change as stressed organisms expel waste. These conditions make it challenging enough to survive, but what happens when a resilient invader shows up?

Celia Olabarria and her colleagues decided to investigate, using a series of experiments to monitor respiration, heart rate, and heat-shock protein levels in mussels during high and low tide scenarios. The key players were Xenostrobus securis, the invasive Australian mussel, and Mytilus galloprovincialis, a commercially important species native to Spanish coastlines. Mytilus’ susceptibility to higher temperatures was already causing concern given global warming, but the addition of X. securis increased uncertainty about the commercial species’ future.


Olabarria approached these questions using traditional and futuristic approaches. To monitor the temperature fluctuations in the intertidal zone, her team used “robo-mussels”—basically data loggers housed within mussel shells and planted within different areas of a mussel aggregation. The variability was immense: 16º C when submerged and up to 45º C when exposed during low tide (that’s 61-113º F for those not metrically inclined)! With this data in hand, laboratory experiments were then designed where collected mussels were arranged into single and mixed-species aggregates and subjected to simulated heat waves during low tides. Throughout the lab experiments, mortality, respiration, heart rate, water loss, production of heat-shock proteins, and gaping behavior (intermittent opening of the shell) were monitored.

Results and Big Picture

Fig. 1: Percentage mortality (a.) and water loss (b.) of single and mixed-species mussel aggregations. Black bars indicate mortality or water loss during a heat wave; grey bars reflect results from non-heat wave control trials. Taken from Olabarria et al. (2016) Fig. 2.

Fig. 1: Percentage mortality (a.) and water loss (b.) of single and mixed-species mussel aggregations. Black bars indicate mortality or water loss during a heat wave; grey bars reflect results from non-heat wave control trials. Taken from Olabarria et al. (2016) Fig. 2.

There were three physical processes or behaviors that were incredibly important: water loss, gaping behavior, and overall mortality. Gaping serves to help stabilize oxygen levels within the mussel, but can also increase water loss during periods of exposure to the air. This behavior, in particular, was of specific interest since Mytilus had never before been described as a gaping species; instead, it had always been listed as one that relied on inefficient anaerobic respiration during low tide. The combination of water loss and gaping behavior is thought to be what contributed to the overall mortality seen in the mussel aggregates. Specifically, single-species aggregates of native Mytilus showed the highest mortality during heat waves, while X. securis coasted through relatively unscathed. However, in mixed-species colonies, Mytilus’ mortality dropped by half (Fig. 1).

But why would a mixed colony with an invasive species result in a drop in mortality for the native animal? Olabarria and her team are speculating it has to do with the gaping behavior. X. securis was known to gape on a regular basis, opening its shells frequently, both during high and low tide scenarios. Even though Mytilus was observed gaping occasionally, the frequency may have been too low to sufficiently change the local environment. In mixed aggregates, the new hypothesis is that X. securis’ gaping results in heat exchange and increases in humidity. This effectively cools the immediate surroundings, increasing Mytilus’ fitness.

There are many more nuanced interactions between these physiological processes, and only the most important results are described here, but this should serve as a reminder that not all “problems” are cut and dry. While invasive species are still a large threat to ecosystem stability, we don’t always know how physiological flexibility will collide with ecological factors. So, what other invasive species do you think might be lending a helping hand as they move into new neighborhoods?


No comments yet.

Post a Comment


  • by oceanbites 3 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 4 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 5 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 6 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 6 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 7 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 7 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 8 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 8 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 8 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 8 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 9 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 9 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 9 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 10 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 11 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 11 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 12 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 12 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 1 year 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