Still north of Barrow, we are deploying CTDs, bongo nets, and van Veen grabs when we have time between mooring operations, which I will get to later this week. Also, a reminder to sign up for the live webinar from the Healy on Tuesday, August 20th at 5pm EST here. Now to the science!
Microplastics (MPs) are ubiquitous throughout the world's oceans. A lot of research has been done on this topic in other parts of the globe and it is now being looked at in the Arctic. There are two types of plastics: hard and soft. MPs are considered by NOAA to be any piece of plastic that is under 5mm in size. Microplastics can come from a variety of sources including cosmetics, clothing, and industrial processes. Primary microplastics are already less than 5mm when they enter the environment. Examples of this includes microfibers from clothing, microbeads, and plastic pellets, or nurdles. Secondary microplastics are created from degradation of larger plastic products such as single-use water bottles, fishing nets, and plastic bags.
When microplastics get into an ecosystem, particularly in oceans, they can be taken in by organisms through ingestion or respiration. When this occurs, it can take weeks to pass through the organism or they can get stuck in structures such as gills. Organisms that have MPs in their system can then be eaten by larger trophic level organisms and will be transferred to the predator.
A 2018 paper by Fang et al. was the first study on MPs in benthic organisms in the Arctic and sub-Arctic waters. Benthic organisms were collected in the Bering and Chukchi Seas at or near some of the DBO lines. 413 organisms representing 11 dominant species were sampled and the researchers calculated an uptake of MPs that ranged from 0.04 to 1.67 pieces per individual organism at sizes from 0.10 to 1.50mm. The main predator in this ecosystem, a sea star named A. rubens, ingested the maximum amount of MPs indicating that trophic transfer along the food chain may play a critical role. The highest value of MPs was found at the northernmost site which suggests that sea ice and cold current represents possible transport mediums. 87% of the microplastics found were made of fiber.
Now that this paper has confirmed MPs in Arctic benthic organisms, more research needs to be done. That is what Kelly Uhlig, in collaboration with the benthic team, is doing. Kelly is collecting surface mud from a trap door at the top of the van Veen grabs. By looking at the microplastics in the mud, Kelly is hoping to make a connection between MPs in benthic organisms and the microplastics found in their environment. Globally, Arctic and sub-Arctic benthic organisms have less MPs present in their systems, but this may change. Evaluation of microplastics in their mud environment will be important in helping to determine the future of these benthic animals.
A Question From the Crow's Nest
What is bioaccumulation?
Answer from previous post: Orcas got the name "Killer Whale" from early sailors who would see pods hunt seals and whales together.