Plastisphere is a man-made ecosystem based on Plastic debris in the ecosystem. This PPT describes the formation and importance of Plastisphere in an aquatic ecosystem.

1. ‘Plastisphere’: A menace to the
Aquatic Environment
Presented by
KANTHARAJAN G
AEM-PA6-01
Aquatic Environment & Health Management Division,
ICAR-Central Institute of Fisheries Education,
Mumbai18-Jun-18 1

2. Plastics : A man made threat
 First report of plastic in the oceans dating from 1972 (Carpenter & Smith 1972)
 Most abundant form of man-made debris in the sea (Barnes et al., 2009)
 The present global plastic production exceeds 335 mt/year and it is estimated
that up to 5% of this is entering the ocean as Plastic Marine Debris (PMD)
 About 35 kg of plastic per person per year for each of the seven billion people
on the planet (Statistica.com)
 Distributed – from benthic Arctic habitats, Polar sea ice layers to deep sea
canyons
 Quantification, fate, toxicity & persistence of plastic is known
 Impacts of plastics on aquatic life, economic loss is well studied
‘Ecosystem level effects of Plastic Debris are explored well, but not the plastic
ecosystem’
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3. Life on Plastics
 In the early 1970s, Carpenter and Smith
reported for the first time the presence
of diatoms, bacteria & hydroids on the
surfaces of plastic debris collected in the
Sargasso Sea
 Sieburth (1975) noted the ubiquity of
microbial colonization on man-made
surfaces HDPE bleach bottles in his
pictorial essay book "Microbial
Seascapes“ with SEM images of pennate
diatoms, filamentous cyanobacteria,
coccoid bacteria and bryozoans
Fig: SEM images of pennate diatoms, filamentous
cyanobacteria, coccoid bacteria
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4.  Term “Plastisphere” to refer to ‘the thin layer of diverse metazoan and microbial life
that develops on any piece of plastic in aquatic environments’
 Ecosystems that have evolved to live in human-made plastic environments.
 Coined by Zettler et al., 2013. Sea Education Association, Woods Hole, United States.
 Diverse microbial community of heterotrophs, autotrophs, predators, and symbionts,
a community attached to a Plastic marine debris.
‘Plastisphere’ - A man made ecosystem
 Zettler et al., 2013 identified more than
1,000 species of bacteria and algae
attached to microplastic debris, including
members of the pathogenic bacteria.
 Plastisphere communities are distinct
from surrounding surface water,
implying that plastic serves as a novel
ecological habitat in the open ocean.
Fig: Dr. Zettler removing the plastic debris for further examination
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5. Physically and chemically distinct from surrounding seawater
and naturally occurring substrates such as macroalgae,
feathers, and wood, with the potential to select for and
support distinct microbial communities.
Provides a substrate for microbes that lasts much longer than
most natural floating substrates
Hydrophobic surface rapidly stimulating biofilm formation in
the water column
Hydrocarbon – providing nutrient for the survival in the
oligotrophic open ocean (closed loop of nutrient cycling)
The long residence time of plastic favoring the survival of
colonists - PMD within the gyre – remains for decade
PMD concentration 5 × 105 pieces/km2 // ‘Great Pacific garbage
patch’ is bigger than France, Germany and Spain COMBINED
‘Artificial microbial reef’ – presence of primary producer,
primary consumer & predator - like a coral reef ecosystem
Plastic Debris to ‘Plastisphere’
18-Jun-18 5(Zettler et al., 2013; Amaral-Zettler et al., 2015)

6. Fig: Garbage patches around the globe18-Jun-18 6

7. Hydroids
Colonizing
after 7 days
Diatom –
earliest &
most
abundant
Eukaryotic
(about 2
weeks)
Bacterial
biofilm
Minutes –
hrs. of
colonization
(24-72 hrs)
Fig: a) Bacteria on plastic surface; b) Pennate diatoms dominating surface of PS after just 1 week immersed in seawater;
c) Hydroids on plastic surface
Succession of ‘Plastisphere’
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(Quero & Luna, 2017; Mincer et al., 2016)

8. Primary colonizers: Gammaproteobacteria & Alphaproteobacteria
Secondary colonizers: Bacteroidetes
Core community: Hydrocarbon degrading bacteria (Phormidium sp., Pseudoalteromonas
sp., Hyphomonadaceae)
Plastic items retrieved from sediments
Primary colonizers  Secondary colonizers  Core bacteriome
Arenicella and Methylotenera, Sulfurovum and Maritimimonas - early stage;
Robiginitomaculum - middle stage; Sulfitobacter and Psychroserpens in the late
late stage of exposure
Plastics collected from offshore waters
Dominated by Flavobacteria and Gammaproteobacteria
Core microbiome: Bacteroidetes (Flavobacteriaceae) and Proteobacteria
(Caulobacterales, Hyphomonadaceae Rhodobacteraceae and Alcanivoracaceae)
Microbial life in Beach pellet
Actinobacteria is the different microbial group
(Quero & Luna, 2017)
Microbial life on ‘Plastisphere’
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9.  Presence of associated compounds:
Anthracene in plastic pellets - Presence
of Mycobacterium frederiksbergense 
metabolize Anthracene derivatives,
which are used in preparing color
pellets
(De Tender, 2017; Amaral-Zettler et al., 2015)
Factors affecting the formation & composition of
Plastisphere
 Envt. Factors: Higher Salinity is
negatively correlated with the MPD
samples
 Location: Communities differ more by
geography: Eg: Rhodobacterales –
most common & dominant group in
Western Pacific / communities in the
North Sea were dominated by
Bacteroidetes and Cyanobacteria
 Plastisphere communities exhibited
higher species richness in the tropics in
the Northern Hemisphere during the
summer months.
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10.  Zettler et al., 2013 assessed the microbial communities in PMD at multiple locations in
the North Atlantic seawater, Polypropylene, Polyethylene & Sargassum seaweed
 Seawater had the largest number of unique OTUs (n = 1789)
 Collectively found 350 bacterial OTUs shared between the PE and PP samples
 Seawater shared a minor proportion of its OTUs with PE (8.6%) and PP (3.5%),
respectively
 In contrast, 40% of the OTUs shared between PE and PP
Peculiarity in the Microbial diversity
(1) Seawater samples had the highest average richness and polyethylene the lowest,
but when normalized with respect to sampling effort (number of reads recovered), the
greatest richness in a single sample was associated with polypropylene
(2) plastic substrates showed greater evenness than seawater
- Plastics (mean Simpson evenness 0.95) compared to seawater (0.89) & the
brown alga Sargassum (0.90)
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Seawater vs Plastisphere

11. Fig 1: Bar chart showing similarity between all three seawater samples and dominance of a relatively small
number of abundant OTUs, versus plastic samples with greater variability between samples and greater
evenness indicated by more groups representing smaller proportions of the total population.(Zettler et al., 2013)
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12. (22) Oceanospirillales
(24) Rickettsiales
(25) Pelagibacter
(26) Rhodospirillaceae
Flavobacteriaceae
(31) Prochlorococcus
(32) Acidimicrobiales
(1) Verrucomicrobia, Rubritaleaceae (2) Proteobacteria, Vibrionales (4)
Gammaproteobacteria; (5) Alphaproteobacteria, Sphingomonadales,
Erythrobacteraceae (6) Thalassobius; (7) Rhodobacteraceae; (8)
Parvularculaceae (9) Caulobacterales, Hyphomonadaceae (10)
Unassigned, Phormidium; (11) Cyanobacteria (12) Saprospiraceae,
Lewinella; (13) Sphingobacteriales, Flammeovirgaceae, Fulvivirga; (14)
Chitinophagaceae; (15) Myxococcales; (16) Anaerolineae, Anaerolineales,
Anaerolinaceae; (17) Saprospira; (18) Flammeovirgaceae; (19)
Flammeovirgaceae, Marinoscillum; (20) Alteromonas; (21)
Rhodobacteraceae, Rhodovulum; (22) Oceanospirillales (23)
Pseudoalteromonas; (24) Rickettsiales (25) Pelagibacter; (26) Bacteria,
Proteobacteria, Alphaproteobacteria, Rhodospirillales, Rhodospirillaceae;
(27) Flammeovirgaceae, Amoebophilus; (28) Sediminibacterium; (29)
Flavobacteriaceae;
(30) Oceanospirillaceae, Oceaniserpentilla
Abundant microbial species groups
Seawater
Plastisphere
(Zettler et al., 2013)18-Jun-18 12

13. •LD plastics - no Nitrogen
during production
•Elemental analysis of
PMD - 1% N 
corresponds to 6.6% of
biomass (106:16 = C:N)
C  N
•Floating PMD in
ocean = 14, 400 –
2,68,000 mt
•Correspond to 860
- 16, 000 mt of
biomass carrying
capacity
Carrying
Capacity of
Plastisphere
•1 g PMD  contains
6.6% of microbial
biomass (0.06 g/g)
•Avg. amount of
C/microbial cell is 20 fg
& an avg. of 5 x 10^8
microbial cells/l of open
ocean seawater (0.01
g/1000 l)
1 g PMD
Vs
1000 l of Open
ocean SW
(Mincer et al., 2016)
Microbial biomass in Plastisphere
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14. Models have shown that plastic can migrate over 1,000
km, from the coastal waters of the Eastern Seaboard
(USA) to the North Atlantic Subtropical Gyre, in < 60 days
Plastic originate from land and sea-based sources with
their natural bacterial communities  if the affinity for
the plastic material is high enough, micro-organisms could
stay attached on plastic despite changing environments
Zettler et al. (2013) documented the presence of Vibrio, on
plastic fragments in the Atlantic, & a potentially
pathogenic Vibrio parahaemolyticus from the North Sea &
Baltic Sea
Masó et al. (2003) has found cysts of a the dinoflagellate
Alexandrium taylori (HABs), attached to plastic debris
found in coastal and open ocean waters in the
Mediterranean Sea and other places that have not been
affected by HAB events before.
Potentially harmful algae (Ostreopsis and Coolia spp.,)
have been discovered on plastic in the Mediterranean Sea
‘Plastisphere’ – vector for harmful organism
Fig: Ostreopsis
Fig: Alexandrium taylori
18-Jun-18 14
(Kirstein et al., 2016; Law et al., 2010)

15. Contd…
Relative abundances of Aeromonas spp. (a genus harboring fish pathogens)
were increased on riverine plastics, implying that such species could take
advantage of plastics as vectors
This possibility is reinforced by the presence of Aeromonas salmonicida,
causing furunculosis in hatcheries, on several plastic types
Recently, 16S rRNA gene sequences affiliated to Tenacibaculum spp. (another
genus including fish pathogens) were detected on PET in seawater.
Transfer of Antibiotic-resistance genes, metal-tolerance or sequestration
genes, and virulence factors are among the genes that may be enriched in
Plastisphere microbiomes
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(Carballo et al., 2000; Mincer et al., 2016; Harrison et al., 2018)

16. Detection of pathogenic bacteria Vibrio in
biofilmcoated microplastics (Plastisphere)
more likely than bare microplastics
Increase the risk of Vibrio infection in humans
in or near waters heavily polluted
Human Health
Implications
(Kirsteinet al., 2016)
Effect of microbial associated plastic
through food chain?
Van der Meulen et al. (2014) found 150
different bacterial species colonizing
microplastics found in the intertidal
region, including those associated with
causing diseases in humans such as E. coli
& Pseudomonas anguilliseptica.
Microplastics coming from WWTPs
have been in close contact with FIOs,
members of Campylobacteraceae & a
range of human faecal pathogens
Established link: Microplastic  Plankton 
Fish  Human
Beach Water Quality
(Keswani et al., 2016)
What our food eats, we eat too
(Oberbeckmann et al., 2015;
McCormick et al., 2014)
‘Plastisphere’ – Impact on Human health
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17.  Microbial biofilms also have the potential to influence invertebrate settlement
which would have an additional significant impact on the buoyancy of PMD
Polyethylenes &
polypropylenes have specific
gravity of about 0.900 to
0.970.
Styrenes, Nylons,
Polyesters, Polyurethanes,
Vinyls -- range from about
1.050 to about 1.440.
Seawater = 1.027
SINK
FLOAT
 Fouling by highly buoyant microorganisms (e.g., cyanobacteria with gas vacuoles)
may temporarily increase the overall buoyancy of the plastic
Sinking velocities of PS increased by 16% in estuarine water (salinity 9.8) and 81% in
marine water (salinity 36) after 6 weeks of incubation
Influencing the sinking of Plastics
18-Jun-18 17(Kaiser et al., 2017; Yokota et al., 2017)

18. o Hydrophobic Organic Contaminants (HOCs)
may be enriched up to 10^6 fold compared to
those of the surrounding sea water
o During the production, Anti-microbial agents added to plastic - these substances
may leach and promote the spread of resistance adaptations in microbial
communities
Transport of Plastic-Associated Pollutants
o Highly persistent contaminants may be
accumulated by plastic from its immediate
environment
o Biofilm acting as a barrier: EPS matrix contain Carbohydrate, Lipid, Protein & Humic
acid which obstruct the sorption of HOCs on plastic
o A wide range of bacteria, fungi, and algae are
capable of degrading HOCs – leaching of
pollutants
Rummel et al., 2017
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19. Protection Degradation
GOOD: Disintegrate the plastic material BAD: Converted in to Micro size plastic
Plastic disintegration (Diaz et al. 2013; Yokota et al., 2017)
‘’Hydrocarbon
degrading bacteria
actively hydrolyzing the
plastic rather than
depending upon
inorganic nutrients
released by earlier
colonizers of the
microplastic particle or
present in the wider
environment’’
Microbes accelerating weathering?
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20.  The biofilm-coated nature of the Plastisphere – which may smell, taste, & look like
food items – attractive to selective grazers, particularly those feeding in the
oligotrophic ocean
 A piece of plastic passing through an animal’s gut remains intact &, when excreted,
provides a pulse of nutrients to the Plastisphere community particularly to
opportunistic pathogens like Vibrio bacteria that survive the digestive tract
environment.
 Plastisphere serves to concentrate microbes that may require a minimum number of
cells to infect a host and express pathogenicity genes.
 Plastisphere communities are subject to grazing by vertebrates & also by predatory
bacteria, ciliates, and other grazers  transforming community composition
 Ingestion, as a form of disturbance  resetting colonization
 This would short-circuit the role of evolutionary diversification (or gradual changes
in community structure over long timescales) and dispersal in Plastisphere
community shaping
Microbes of Plastisphere interactions with
Biota
18-Jun-18 20(Amaral-Zettler et al., 2015)

21. Unanswered questions
What are the effects of pH on the release or transformation of POPs and
other toxicants?
Are Plastisphere communities automatically ‘reset’ after ingestion?
Do some members survive the journey?
Are new colonizers picked up along the way?”
Contd…
18-Jun-18 21

22.  Sources & transport between habitats: Plastics transported downstream along
rivers & streams to ocean, whether they remain viable and active upon entering
marine habitats
 In situ biodegradability of Plastics and associated compounds: product of
degradation process & its effect; comparison of lab & field level study
 Links between plastic debris, pathogens and public health
 Better characterization of microbial interactions with the persistent,
bioaccumulating, and toxic substances contained on Plastisphere.
Harrison et al., 2017; Keswani et al., 2016
Knowledge gap & Future research
- Studies so far have just scratched the surface addressing
important questions about microbial community assembly
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23. Conclusion
 Plastic consumption increases day by day, without any environmental
concerns
 Plastics effect on aquatic animal focused much than the associated
microbes which pose huge threat to the ecosystem
 ‘Plastisphere’ – A new concept to understand the microbial ecology on
plastic debris
 Exhaustive understanding of Plastisphere, not only help us in the pollution
management but also to find the way for plastic bioremediation
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24. 1. Amaral-Zettler, L. A., Zettler, E. R., Slikas, B., Boyd, G. D., Melvin, D. W., Morrall, C. E., ... &
Mincer, T. J. (2015). The biogeography of the Plastisphere: Implications for policy. Frontiers in
Ecology and the Environment, 13(10), 541-546.
2. De Tender, C. A., Devriese, L. I., Haegeman, A., Maes, S., Ruttink, T., & Dawyndt, P. (2015).
Bacterial community profiling of plastic litter in the Belgian part of the North Sea. Environmental
Science and Technology, 49(16), 9629-9638.
3. Diaz, J. M., Hansel, C. M., Voelker, B. M., Mendes, C. M., Andeer, P. F., & Zhang, T. (2013).
Widespread production of extracellular superoxide by heterotrophic bacteria. Science, 1237331.
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The size, mass, and composition of plastic debris in the western North Atlantic Ocean. Marine
Pollution Bulletin, 60(10), 1873-1878.
5. Harrison, J. P., Hoellein, T. J., Sapp, M., Tagg, A. S., Ju-Nam, Y., & Ojeda, J. J. (2018). Microplastic-
associated biofilms: A comparison of freshwater and marine environments. In: M. Wagner, S.
Lambert (Eds.), Freshwater Microplastics (pp. 181-201). Springer, Cham.
6. Kaiser, D., Kowalski, N., & Waniek, J. J. (2017). Effects of biofouling on the sinking behavior of
microplastics. Environmental Research Letters, 12(12), 124003.
7. Keswani, A., Oliver, D. M., Gutierrez, T., & Quilliam, R. S. (2016). Microbial hitchhikers of marine
plastic debris: Human exposure risks at bathing waters and beach environments. Marine
Environmental Research, 118, 10-19.
References
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25. 8. Mincer, T. J, Zettler, E. R, Amaral-Zettler, L. A (2016) Biofilms on plastic debris and their
influence on marine nutrient cycling, productivity, and hazardous chemical mobility. In: Takada
H, Karapanagioti HK (eds) Hazardous chemicals associated with plastics in the marine
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9. Quero, G. M., & Luna, G. M. (2017). Surfing and dining on the “Plastisphere”: Microbial life on
Plastic Marine Debris. Advances in Oceanography and Limnology, 8(2), 199-207.
10. Rummel, C. D., Jahnke, A., Gorokhova, E., Kühnel, D., & Schmitt-Jansen, M. (2017). Impacts
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producers and microplastics. Limnology and Oceanography Letters, 2(4), 91-104.
12. Zettler, E. R., Mincer, T. J., & Amaral-Zettler, L. A. (2013). Life in the “plastisphere”: microbial
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13. https://www.statista.com/statistics/282732/global-production-of-plastics-since-1950/
Contd…
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26. Thank You
#beatplasticpollution
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