//
you're reading...

Plastic

Giant Clams vs. Small Plastics

Microplastics are found all throughout our oceans. But in the Red Sea, there are a lot less. Find out how giant clams could be a culprit for getting rid of small plastics.

Arossa, S., Martin, C., Rossbach, S., & Duarte, C. M. (2019). Microplastic removal by red sea giant clam (Tridacna maxima). Environmental Pollution. doi:10.1016/j.envpol.2019.05.149

We use plastics everyday, from disposable water bottles to plastic grocery bags. Often these end up in landfills but they can also make their way into our oceans. As larger plastic items degrade and break into many particles, they produce microplastics. These tiny plastic particles seem to be taking over our oceans. With plastics ranging in the form of ghost nets to microbeads floating around in our oceans, we search for ways to remove them. Could a large floating beam sweep up the entire Pacific Garbage Patch? Will divers collect plastics from remote islands? Perhaps a much smaller plastic collector is already at work. Arossa’s team (King Abdullah University of Science and Technology) was the first to describe plastic removal by giant clams.

Although a pervasive problem for the oceans, not all bodies of water appear to have the same levels of these pesky plastics. In the Red Sea, for example, there are much lower concentrations of microplastics than neighboring bodies of water. Could it be that organisms in the Red Sea are removing the plastics? Arossa’s team thinks that certain organisms like giant clams serve as plastic “sinks”, accounting for the lower levels of microplastics observed in the water .

Figure 1. Plastics and microplastics found on beach. Source: Wikimedia Commons.

Plastics in Disguise

What makes a clam such a strong candidate for plastic removal? If you think about it, clams and other bivalves are sort of like the vacuums of the sea. As filter feeders, they siphon in tiny particles of food—typically plankton—and begin to digest them. Anything they don’t consume is then expelled back through the siphon.

Often, microplastics resemble tasty plankton, both in size and color. This is why Arossa’s team believes that clams are eating harmful microplastics. To test this, they put clams from the Red Sea in seawater with varying concentrations of microplastics. After 12 days they found that the clams did, in fact, actively digest some of the plastics. But only a small percentage of the missing microplastics were actually found in the clams’ digestive tract. So where were the lost microplastics?

Figure 2. Tridacna gigas, giant clam. Source: C. Sartor.

Plastic Adornments

35% of the microplastics had actually attached to the shells of the clams like jewelry! Arossa’s team thinks that the nooks and crannies of clam shells can allow small particles to become embedded on their surfaces. So, if plastics are sticking to their shells, does it matter if they clams are dead or alive? According to Arossa’s team, it did not. When they put the same amount of microplastics in the water with dead clams, the beads stuck to the shells, just in lower abundances. However, when the researchers increased the amount of microplastics in the water tanks, increasingly more microplastics stuck to the clams’ shells. It seems that Arossa’s team has found a potential sink for microplastics in the Red Sea.

Potential Plastic Sink?

Through digestion and passive attachment, giant clams in the Red Sea are removing microplastics from the water column. With high rates of calcification, the team even thinks that the plastics will be encrusted into their elaborate shells. But are clams actually a microplastic sink? Perhaps only temporarily. Further studies must be conducted to determine if the plastics are released back into the ocean when the plastic-filled clams die. But the fact that clams are ingesting plastics remains. And it all comes down to our disposal of plastics. If you don’t want microbeads in your clam chowder, take action to reduce your use of plastics.

 

Discussion

No comments yet.

Post a Comment

Instagram

  • 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 8 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 11 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