THE OCEANIC PLASTISPHERE

Characterization of Diatoms & Microbes Attached to Microplastics

IMBRsea Cohort 2020 - 2021

Hi, I'm Charles and I performed my Professional Practice at the Stazione Zoologica Anton Dohrn in the magnificent city of Naples in Italy. I worked on the characterization of Diatoms and Bacteria that are living on the microplastics in the gulf of Napoli.

The aim of the research was to know what is thriving on the microplastics and what effect it has on these tiny particles. With this site I would like to teach students more about the plastic pollution in general and the research I performed in Naples. Have a look around & enjoy!

Little introduction to plastic pollution

From revolutionary material to common waste

Plastic pollution by Kurzgesagt

Where is all the missing plastic hiding?

Missing Plastic by VOX

Root cause of Oceanic plastic pollution

Plastic production: 380 Mega Tonnes

Production is not slowing down

Packaging waste main polluter

Single-use ban has yet to make an effect

Landfill = primary path for single-use

Only a fraction (green) is being recycled

How does plastic waste end up in the Oceans?

CLICK TO FIND OUT

Do you wonder where all that waste comes from? Locate the most polluted river close to where you live on this interactive map (click picture)

Microplastics under the spotlight

The dangers of Oceanic Microplastics

Contain harmful compounds from manufacturing.
Trophic poisoning due to bioaccumulation.
Physically damage suspension- and deposit-feeding fauna.
Alter pelagic & sediment-dwelling biota by modifying physical properties of their habitats.
Carry & transport rafting species, as well as species capable of grazing upon these plastic inhabitants.
Degrading even further into Nanoplastics, particles small enough to enter living cells.

The Microplastic Plastisphere

Community of micro-organisms living on these microplastics.
Some m.o. are toxic and can poison the trophic chain.
Form an extensive biofilm that alters the fysiochemical properties of the microplastics, especially important regarding the particle's density.
Crucial to establish the presence and densities of the groups of organisms living in the plastisphere.
Possibly brake down the plastic by feeding of the polymers and associated compounds.

RESEARCH ON MICROPLASTICS IN NAPLES

- What did I do -

1 - Microplastic sampling

Sampling of microplastics with Manta net

gulf of Naples - gulf of Gaeta

Handling & Preparation of the samples

2 - SEM analysis Plastisphere

Estimating the coverage index of biofilm on 500x

Counting and categorizing Diatoms on 500x

Counting and categorizing Bacteria on 1500x

3 - Microplastics counting

One sample consisting of two subsamples

Determining under microscope:

Type - Colour - Size

EXPERIENCES

- Location snippets (see dropdown) -

Left picture upper corner - Location of the professional practice; Naples [Italia]
Left picture lower corner - Gulf of Naples; where most of the sampling was executed.
Right picture: The Stazione Zoologica Anton Dohrn where I performed my professional practice; second oldest research center in Europe. It was founded in 1872 by Anton Dohrn, who was friends with Charles Darwin, and thus considered a prominent Darwinist.

EXPERIENCES

- Interesting microplastic snippets -

Microplastic counting and classification.

Microplastics are classified into sizes, colours & type
The most common types are fragments, followed by films & filaments.
Microbeads (type used in cosmetics, now banned) were actually very rare.

(picture: example of a microplastic fragment)

Guess how many pieces are in this petridish.

ANSWER: 779 pieces (and yes they were all counted by hand)

Using a flow meter the filtered volume of the sampling net is calculated --> 212 m^3
This sampling location in the gulf of Naples thus contains: 3,6 pieces/ cubic metre of SW!
Average Microplastic pieces in the Mediterranean: 1 piece/cubic metre of SW .

EXPERIENCES

- Interesting SEM snippets -

Train like a professional SEM picture analist (see dropdown menu)

Below is an example of the SEM picture that had to be analysed, in this case one for Bacteria!
In total 13 samples were analysed, each containing 12 of these pictures (6 for Diatoms + 6 for Bacteria), or in total 156 SEM pictures.
Each photograph was loaded into the program ImageJ, which was used to count the Diatoms and Bacteria, see the example to have a taste in the procedure.
All data was checked by the coordinator and noted in an excel file.

(In the example below yellow = Cocci - purple = Bacilli)

EXPERIENCES

- Little SEM data snippets -

SEM picture Diatom data example

In this example we see three sampling stations (locations) and their corresponding Diatoms counts per square millimetre. These were found by averaging the SEM pictures counts per sample like shown before, and dividing this number by the surface area of the a SEM picture at 500x.

Cells indicated in red show no colonisation by this type of Diatom. The question is then raised; how can certain sampling locations contain more Diatoms and others be devoid of them. There are multiple hypotheses for this phenomena, one of the possible reasons could be that these un-colonised MP are actually virgin pieces that have only recently entered the gulf via the river.

Using ocean current maps with winter - summer anomalies, the drifting behaviour of the MP could be predicted. The hypothesis that some MP are originating from a nearby river and directly float towards one of the sampling locations could then be considered plausible, but this still requires more research, as lots of other theories are also possible (please contact me if interested - I can explain in detail)

Acknowledgement

A big thank you to my supervisor and coordinator for the wonderfull professional practice in Naples