3. Plastic Pollution in the Marine
Environment
3
• 200 billion pounds each year;
10% in ocean
• First awareness of the impact
of plastic pollution in 1960s
• 46,000 pieces of floating
plastic per square mile
Photo: U.S. National Oceanic and Atmospheric Administration
4. 4Ref: http://dx.doi.org/10.1016/j.marpolbul.2011.05.030
Plastic Types and Sources
Plastic Class Abbreviation
Products and
typical origin
Percentage
production
Product for Experiment
Low-density
polyethylene
LDPE LLDPE
Plastic bags, six-
pack rings,
bottles, netting,
drinking straws
21%
High-density
polyethylene
HDPE
Milk and juice
jugs, grocery bags
17%
Polypropylene PP
Rope, bottle caps,
netting, plastic
mat
24%
Thermoplastic
Polyester
PET
Plastic beverage
bottles
7%
Poly(vinyl chloride) PVC
Plastic film,
bottles,
cups,gloves
19%
5. Impact of Plastic Pollution on Marine
Organisms
5
https://marinedebrisblog.wordpress.com/category/international-coastal-cleanup/
http://academlib.com/24906/environment/plastic_marine_debris_comple
x_mixture_chemicals
10. Aims of the Project
10
To determine physiological changes in Prochlorococcus and Synechococcus in
response to short and long term exposure to different types of plastic
leachates
Explore the genetic and transcriptomic basis for the variability in leachate
stress responses observed across Prochlorococcus and Synechechoccous
strains
Develop modified Toxicity identification Evaluation (TIE) approaches suitable
for Prochlorococcus and Synechechoccous to characterise, identify and
confirm the basis of plastic leachate toxicity in these organisms
11. Aim 1 – Plastic Leachate Impact
11
Aim-1
Leachate preparation
(HDPE,PET,PP,LDPE,PVC)
Exposure of Prochlorococcus &
Synechococcus to leachate
across concentration gradient
Optical
density
Cell
count
Photosynthetic
quantum yield
Chlorophyll a
fluorescence
14. 14
Low Light Ecotype High Light Ecotype
Response of Prochlorococcus
Strains to HDPE Leachate Exposure
15. 15
Prochlorococcus & Synechococcus
Control and leachate treated
RNA extraction
Genome-wide mRNA sequencing (RNAseq) and RT-PCR
Analysis of transcriptional patterns under different stress conditions- determine
sets of differentially expressed genes (Edge-Pro, DESEQ)
Aim-2
Aim 2-Examining the Transcriptomic Basis
for Variability in Leachate Stress Responses
16. Aim 3 – TIE Test: Determine the Contribution of
Individual Toxicants to Plastic Leachate Toxicity
16
Phase -1
Characterization
Phase -3
Confirmation
Phase -2
Identification
• Removal of
hydrophobic organics
• Removal of metal ions
Spectroscopic analysis of
leachate content
• ICP
• LC-MS
Enhance
concentration of
possible toxicants for
variation
Aim-3
TIE Test
17. Time Frame
17
~
Plans 2016(June-
Dec)
2017(Jan-
Dec)
2018(Jan-
Dec)
2019(Jan-
June)
Literature review
Aim 1: Exposure of Prochlorococcus &
Synechococcus to leachate across
concentration gradient
Aim 2 : Examining the transcriptomic basis
for variability in leachate stress responses
Aim 3: To develop TIE method to
determine of individual toxicants
responsible for plastic leachate toxicity
Write up manuscripts and thesis
Hello everyone, This is Indrani Sarker, PhD student, Chemistry and biomolecular sciences. I am carrying out my research under Sasha Tetu. Today I am here to present my first year talk and going to introduce all of you with my project briefly. The title of my project is ……
The ocean is one of the most expansive, mysterious and diverse places on Earth.
Unfortunately, it is being threatened by different types of anthropogenic pollution as well as climate related stress and as a result Marine life is dying, the whole oceanic ecosystem is endangered. Millions of seabirds and thousands of sea mammals die each year due to ocean pollution. Already 500 dead zones have been reported where oceanic ecosystem have collapsed.
Land-based sources (such as agricultural run-off, discharge of nutrients and pesticides and untreated sewage) account for approximately 80% of marine pollution,
As you can see from the picture land based discharage of plastic into the oceans is a growing and globally recognised problem – and plastic is now recognised as an important marine pollutant
You have probably heard in the news about the growing issue of plastic pollution
According to Greenpeace, the world produces 200 billion pounds of plastics every year and ten percent of that(20 billion pounds) ends up in our oceans
Plastic debris in our oceans was first observed in the 1960s and the abundance has continued to increase over the last 40 years
According to a united nations estimation there are 46.000 floating plastic pieces are there in the ocean in each square mile
So what are the main types of plastic which are produced and are problematic in regards to marine pollution
There are five main classes of plastic which account for about 80% of global production around the world at the moment-
Table shows percentage of production and typical products of different types of plastics that are commonly encountered in the marine environment.
We will be focusing on 5 types(LDPE,HDPE,PP,PET& PVC).
Most common plastic rubbish items are plastic bags and bottles – so these are considered major ecological threats
(HDPE,PET)
The other three main types are also problematic as they have known toxicity
It is indeed a big question that how does this plastic pollution impacts marine organisms
Current research and environmental efforts focus on adressing the physical hazards associated with plastic debris in the marine environment such as ingestion and entanglements to larger organism
s
but this plastic is actually a cocktail of different chemical contaminants(on the other picture) which might have severe chemical hazards to the marine organisms.
the greater mount of research so far has been dealing with microplastics and ingestions, where there is a knowledge gap on what these plastics leach and what the impact of that one is?
Looking at the worldwide distribution, prochlorococcus more abundant in tropical water synechococcus almost everywhere
Why we are working with this?
they can represent up to 60 % of marine biomass
These single-celled organisms are responsible for more than 40% of Earth’s photosynthetic production
If we look at the picture The organisms are extremely important because they form the very bottom of the food chain.
as I said before people so far have studies the impact of plastic toxicity on the larger animal like marine mammals, sea birds and larval stages of smaller organisms. But the fate of plastic leachate toxicity to the organism of this part of ocean(indicating with a red arrow) is key to understanding how the whole ecosystem will be affected
So why hasn’t this been done? Why don’t ecotox studies focus on the key producers ? This is because these are much harder to work with!
Primary producer-bottm of food chain.
Prochlorococcus is the "smallest and most abundant" marine microbe
Talk about how they are categorised
Pros based on position in water column
Syn ecotypes
Strain collection with representative of
Prochlorococcus: HL and LL ecotypes
Synechococcus XXXXXX subclusters
Distribution
Strain collection
Prochlorococcus: HL and LL ecotypes
Synechococcus subclusters
In my phd I will carry out experiments using a number of strains of syn and pro which span the diversity of this important group of photosynthetic marine organisms and also cover the main ecotypes
I have already begin to target my aim 1
Presenting some of the initial results of my experiment. There was no consistency found between the growth of two species after exposure to HDPE leachate.
The photosynthetic quantum yield was also different for two ecotypes. But there is definitely a toxicity found for both of the species after 48 of treatment with leachate.
Photoinhibition
The quantum yield of photochemical energy conversion in PSII (Yield) is calculated by the equation:
Yield = dF/Fm
was dark-adapted and, hence, Yield corresponds to the maximal PSII quantum yield (commonly referred to as Fv/Fm).
miRNeasy Mini Kit
EDGE-pro (Estimated Degree of Gene Expression in Prokaryotes) processes the raw data from an RNA-seq experiment on a bacterial or archaeal species and produces estimates of the expression levels for each gene in these gene-dense genomes.
TIE(toxicity identification evaluation test)
Phase 1: Cations chelated by EDTA include certain forms of aluminum, barium, cadmium, cobalt, copper, iron, lead, manganese, nickel, strontium, and zinc
The sodium form of purified Chelex-100 can be used to remove trace metals from artificial and natural seawater without altering the major cation-anion composition or con- tributing organic toxicants or chelators.
Phase-3: Confirmatory evidence can also be obtained through a number of approaches involving spiking samples with the suspect toxicant(s). In general, if the investigator notes an increase in the toxicity of a sample in the same proportion as the increase in concentration of the suspected causative toxicant, the candidate toxicant can be confirmed as the true toxicant. To get a proportional increase in toxicity from the addition of a suspect toxicant when in fact it is not the true toxicant, both the true and the suspect toxicants would need to have very similar toxicity levels and would presumably have to be additive. Like correlation, this can be a powerful approach, but must be conducted and interpreted carefully, with consideration of possible interferences and confounding factors.
Metal: Inductively coupled plasma emission spectroscopy (ICP)
Polar organics:LC-MS analysis
