Marine plastics are formed from the breakdown of macroplastics, they can be found all over the marine habitats. They can be considered a threat due to the harmful chemicals added during the manufacturing process which can be transferred into the surrounding water as well as that they are entering food chains. However this paper looks at the possibility of the marine plastics providing a new niche/ habitat for the planktonic organisms.
Methods:
6 different regions around the coast of Australia were sampled by using nets and trawls to collect the buoyant plastics. Scanning electron microscopy (SEM) was used to examine the organisms inhabiting 68 buoyant marine plastics (length range = 1.7–24.3 mm, median = 3.2 mm).
Results:
Many taxa were found during the survey, the most abundant, diverse and widespread plankton found were the diatoms since they were found in every sample around Australia. Most were flat on the surface however some were erect, attached through mucus pads. Coccolithophores were only found in southern Australia plastics. Most found were some detached plates attached to the plastics through chitin and mucus, but some whole examples were found. Only a single specimen of dinoflagellate was found. Many unidentified organisms of various sizes were found that resembled bacteria, fungi and cyanobacteria . They were described as epiplastic rounded, elongated and spiral cells. Some bryozoans colonies were found.
For the benthic diatoms marine plastics seemed to provide a long lasting, abundant new habitat which is light, nutrient filled and stable. It was unclear if this affects the food webs/ chains in negative ways. Coccolithophore species are not recognised as a rafting species however a “significant amount was found” suggesting that they might be using plastics as floating devices. Bacteria like organisms have been found growing on the plastics leaving craters, these observations and detections of bacteria genes on marine plastics suggest that they can degrade polymers, which may explain why the marine plastics aren’t increasing in the oceans as fast as predicted.
My thoughts:
Marine plastics are increasing in the oceans due to their long life and constant supply of new plastics. This will have an escalating effect on how the plankton will travel and live. This study is taking a step forward into understanding how plastics in the ocean will affect the plankton living there. Especially since part of the results supports that some types of bacteria are degrading plastics. Plankton degrading plastics could help in the future when looking for ways to reduce plastic in landfill sites. On the other hand the amounts degraded are tiny and may not be applicable to reducing waste, more research on the applications and ecological impacts of this are needed. By identifying which plankton live on the plastics, we may be able to predict which organisms would be affected by the accumulation of plastics by looking at which organisms consume the types of plankton. There was a relatively small amount of plastics looked at however, this allowed a thorough investigation into each piece of plastic. Nonetheless, a more representative lookout on what is happening in the oceans a larger sample size would be needed.
Reisser, Julia, et al. "Millimeter-sized marine plastics: a new pelagic habitat for microorganisms and invertebrates." PloS one 9.6 (2014): e100289.
Hi Sam,
ReplyDeleteReally interesting paper, I actually read this when I was looking for something to review and thought it was a very good idea. You reviewed it really well, sticking to the core and was a really easy read. I agree with you and your views on this paper, that yes they do need to do this on a larger amount of plastics from a variety of different regions as Australia was the only place sampled. I think it would be great to sample from 'The Great Pacific Garbage Patch' and see really how much potential degradation from the microorganisms there have! It would also be interesting to take strains of the bacteria with 'degrading properties' and really look into the potential of them. All very interesting but the idea definitely needs more work. Thanks for the read!
Elyssa Q
Hi Sam
ReplyDeleteFirst off, well done for being one of the first to put up a post! Thanks for posting a paper on microplastics. I think this is such a fascinating area of microbiology research which hopefully will yield some interesting developments in the future. I agree with Elyssa's comments that you reviewed the paper well and that it would be interesting to see if this microbes associated with microplastics around the world differed in any way. I wonder whether the communities of colonizing bacteria would differ from region to region (ie. plastics found in the Atlantic versus those found in the Pacific)? I also wonder if the fungi found on the plastics had any degrading properties. That would make an interesting follow up for research.
Anita
Hi Sam
ReplyDeleteThis piece has a concise clear introduction which really interested me, as I haven’t to this date read a paper concerning marine plastics as a habitat. I agree with your thoughts that more work could provide a clearer view of phytoplankton present, and examining marine plastics from a wider geographical span would provide additional insight into organism diversity. It would be interesting to see if there has been any further research conducted into species variation as the plastic moves through different environmental conditions within the sea. The difference in conditions could permit the settlement of different microbes, for example a piece of plastic moving with the current from warmer sea temperatures to colder sea temperatures, pushing the lethal boundaries of some microbes and enabling others to settle.
Emma
There's a very interesting paper by Harrison et al just published on experimental colonization of plastics and the possible degradation of hydrocarbons. Maybe someone would like to review this paper? http://www.biomedcentral.com/1471-2180/14/232/
ReplyDeleteHi Sam,
ReplyDeleteThe creation of microhabitats by microplastics seems to be a fascinating area of research. For example, combined with the effects of climate change and warming seas, this could help facilitate the migration and introduction of new microorganisms to different environments or the migration of microorganisms to deeper depths through faster rates of sinking. I disagree with your ideas about using plankton (especially marine) as a means to reduce plastic in landfill sites as these are predominantly terrestrial environments. Soil bacteria have been shown for quite a while now to degrade hydrocarbons but this can still take a long time. Another point to consider is it may be possible that the presence of microorganisms on these microplastics could also have an effect at increasing the uptake of microplastics by zooplankton, hence increasing their abundance in the food web. It would be interesting to study if zooplankton have a greater affinity for microplastics with a microorganism coating than without.
Ben
Very interesting paper and I agree that more research needs to be done in this area as plastics are floating into the remotest of locations, even seas with virtually no human presence in like the seas around Antarctica (Barnes et al., 2010). Since plastic is such an ideal substratum for microorganisms to grow on, organisms can be distributed across the planet. This can have a serious impact on the diversity of the Southern ocean as new species can be added to a relatively unaltered environment.
ReplyDeleteHi,
ReplyDeleteThanks Sam for your interesting post and all the others for their comments. I just read a paper about bioremediation, which I will more talk about in my own post. They also mentioned that in recent studies it has been found that the marine bacteria Rhodococcus ruber degrades 8 % of dry weight of plastic in 30 days (Andrady 2011)!
This weeks lectures gave us some insights into the carbon cycle and the biological pump. I am now wondering how mini marine plastic habitats would have an effect on this carbon cycle and for example the pod of recalcitrant particles? Ben already mentioned the creation of microhabitats by microplastic combined with the effects of climate change, do you think there could be a possibility of marine microplastics habitats helping to increase the amount of fixed carbon?