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Plastics are the most abundant form of marine debris, with global production rising and documented impacts in some marine environments, but the influence of plastic on open ocean ecosystems is poorly understood, particularly for microbial communities. Plastic Marine Debris (PMD) collected at multiple locations in the North Atlantic was analyzed with Scanning Electron Microscopy (SEM) and next-generation sequencing to characterize the attached microbial communities. We unveiled a diverse microbial community of heterotrophs, autotrophs, predators, and symbionts, a community we refer to as the "Plastisphere." Pits visualized in the PMD surface conformed to bacterial shapes as suggesting active hydrolysis of the hydrocarbon polymer. Small-subunit ribosomal RNA gene surveys identified several hydrocarbon-degrading bacteria, supporting the possibility that microbes play a role in degrading PMD. Some Plastisphere members may be opportunistic pathogens such as specific members of the genus Vibrio that dominated one of our plastic samples (the authors, unpublished data). Plastisphere communities are distinct from surrounding surface water, implying that plastic serves as a novel ecological habitat in the open ocean. Plastic has a longer half-life than most natural floating marine substrates, and a hydrophobic surface that promotes microbial colonization and biofilm formation, differing from autochthonous substrates in the upper layers of the ocean.
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Life in the Plastisphere: Microbial Communities on Plastic Marine
Erik R. Zettler,
Tracy J. Mincer,
and Linda A. Amaral-Zettler
Sea Education Association, P.O. Box 6, Woods Hole, Massachusetts 02543, United States
Marine Chemistry & Geochemistry, Woods Hole Oceanographic Institution, 266 Woods Hole Rd., MS#51, Woods Hole,
Massachusetts 02543, United States
The Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, 7 MBL Street,
Woods Hole, Massachusetts 02543, United States
SSupporting Information
ABSTRACT: Plastics are the most abundant form of marine
debris, with global production rising and documented impacts
in some marine environments, but the inuence of plastic on
open ocean ecosystems is poorly understood, particularly for
microbial communities. Plastic marine debris (PMD) collected
at multiple locations in the North Atlantic was analyzed with
scanning electron microscopy (SEM) and next-generation
sequencing to characterize the attached microbial commun-
ities. We unveiled a diverse microbial community of
heterotrophs, autotrophs, predators, and symbionts, a
community we refer to as the Plastisphere. Pits visualized
in the PMD surface conformed to bacterial shapes suggesting
active hydrolysis of the hydrocarbon polymer. Small-subunit
rRNA gene surveys identied several hydrocarbon-degrading bacteria, supporting the possibility that microbes play a role in
degrading PMD. Some Plastisphere members may be opportunistic pathogens (the authors, unpublished data) such as specic
members of the genus Vibrio that dominated one of our plastic samples. Plastisphere communities are distinct from surrounding
surface water, implying that plastic serves as a novel ecological habitat in the open ocean. Plastic has a longer half-life than most
natural oating marine substrates, and a hydrophobic surface that promotes microbial colonization and biolm formation,
diering from autochthonous substrates in the upper layers of the ocean.
Plastic has become the most common form of marine debris
since it entered the consumer arena less than 60 years ago, and
presents a major and growing global pollution problem.
current global annual production, estimated at 245 million
represents 35 kg of plastic produced annually for each
of the 7 billion humans on the planet, approximating the total
human biomass. Some fraction of the increasing amount of
postconsumer plastic trash inevitably escapes the recycling and
waste streams and makes its way to the global oceans.
Additionally, tsunamis and storms can result in large pulses
of plastic entering the ocean from coastal areas. Plastic
accumulates not only on beaches worldwide, but also in
remoteopen ocean ecosystems.
Drifter buoys and physical
oceanographic models have shown that surface particles such as
PMD can passively migrate from Eastern Seaboard locations all
the way to the interior of the North Atlantic Subtropical Gyre
in less than 60 days,
illustrating how quickly human-generated
debris can impact the gyre interior that is more than 1000 km
from land. Plastic debris in the North Atlantic Subtropical
and North Pacic Subtropical Gyre is well-docu-
and models and limited sampling conrm that
accumulations of PMD have formed in all ve of the worlds
subtropical gyres.
The eects of plastic debris on animals such as sh, birds, sea
turtles, and marine mammals as a result of ingestion,
marine entanglement
are well documented, but studies of
plastic-associated microbial communities are lacking, and we
know little about the impact of this anthropogenic substrate
and its attached community on the oligotrophic open ocean. As
a relatively new introduction into the marine ecosystem, plastic
debris provides a substrate for microbes that lasts much longer
than most natural oating substrates and has been implicated as
a vector for transportation of harmful algal species
persistent organic pollutants (POPs).
With a hydrophobic
surface rapidly stimulating biolm formation in the water
column, PMD can function as an articial microbial reef.
PMD at concentrations of up to 5 ×105pieces/km2in the
North Atlantic Subtropical Gyre
represents a new oating
Received: March 26, 2013
Revised: May 26, 2013
Accepted: June 7, 2013
Published: June 7, 2013
© 2013 American Chemical Society 7137 |Environ. Sci. Technol. 2013, 47, 71377146
substrate for microbial colonization and transportation, and the
presence of particles in aquatic systems is known to stimulate
microbial productivity and respiration.
Once trapped in
central ocean gyres, there are very few avenues for export, and
buoyant plastic particles accumulate and may persist for
decades. Increases in PMD have been documented in the
North Pacic Gyre,
but despite increases in plastic production,
use, and presumably input into the ocean, other studies show
no signicant trend in plastic accumulation in the North
Atlantic Subtropical Gyre
or in the waters from the British
Isles to Iceland since the 1980s.
Physical shearing and
photodegradation are proposed mechanisms of plastic degra-
These physical mechanisms may result in
fragmentation into pieces small enough to pass through
standard sampling nets.
In addition, biolm formation and
colonization by invertebrates can decrease plastic buoyancy
allowing some of the plastic debris to sink to deeper waters,
with eventual seaoor deposition.
However, plastic debris is
absent from sediment traps
suggesting that density-mediated
transport of small pieces is relatively low.
PMD has been reported by a number of studies starting in
the 1970s
where authors mention diatoms and other
microbes on the debris. However, our study presents the rst
comprehensive characterization of microbial communities living
on PMD in the open ocean with an emphasis on bacteria. We
hypothesized that this new man-made substrate is 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. Using pyrotag sequencing and SEM,
we investigated representative microbial communities on pieces
of polyethylene (PE) and polypropylene (PP) plastic from
geographically distinct areas from the North Atlantic
Subtropical Gyre and compared them to the microbial
communities in the surrounding seawater. Our analyses
unveiled for the rst time the breadth of PMD microbes that
make up what we call the Plastisphere.
Sample Collection. Plastics were collected in a 1 ×0.5 m
rectangular neuston net with 333-μm mesh towed at the surface
from the Sea Education Association (SEA) vessel SSV Corwith
Cramer as part of SEA Semester research cruises C-230 and C-
241 (Supporting Information (SI) Table S1). Individual pieces
of plastic were sorted with sterile forceps and rinsed with sterile
seawater prior to subdivision using a sterile razor blade and
preservation for DNA extraction and SEM. While the net was
in the water, we ltered 4 L from a clean seawater system
(periodically freshwater-ushed nonmetallic line drawing water
from 3 m below the surface) through a 0.2 μm Sterivex
cartridge lter (Millipore, Billerica, MA) to collect micro-
organisms suspended in the ambient surface water.
Sample Preservation. Plastic and seawater lters for
downstream DNA analysis were immediately ooded with
Puregene lysis buer (Qiagen, Valencia, CA) and frozen at 20
°C. PMD samples for SEM were xed in 4% paraformaldehyde
for 223 h, then transferred to 50% ethanol in Phosphate
Buered Saline (PBS) and kept at 20 °C.
SEM. Preserved plastic samples for SEM were dehydrated on
ice through an ethanol series: 10 min each in 50%, 70%, 85%,
95%, followed by 3 ×15 min in 100% ethanol. Samples were
immediately critical point dried using a Samdri 780A
(Tousimis, Rockville, MD), sputter coated with 5 nm of
platinum using a Leica EM MED020 (Leica Microsystems, Inc.
Bualo Grove, IL), then visualized and imaged on a Zeiss Supra
40VP SEM (Carl Zeiss Microscopy, Thornwood, NY). Cell
measurements were made from digital images using ImageJ
software (Rasband, W.S., ImageJ, U.S. National Institutes of
Health, Bethesda, MD, 1997-2012).
Raman Spectroscopy. The resin composition of plastic
pieces was identied using a PeakSeeker Pro Raman
spectrometry system (Agiltron, Woburn, MA) with a micro-
scope attachment that enabled measurement of spectra from
very small pieces of plastic. Each sample was compared with
reference scans from plastics of known composition. We
selected three pieces of polypropylene and three pieces of
polyethylene that were large enough to subdivide for SEM and
DNA extraction.
Amplicon Pyrotag Sequencing. DNA was extracted
using a modied bead-beating approach
in combination
with the Puregene Tissue DNA extraction kit (Qiagen,
Valencia, CA). We amplied bacterial V6V4 hypervariable
regions of the small-subunit rRNA (SSU rRNA) gene using
primers targeting Escherichia coli positions 518 and 1046.
multiplex-sequenced the resulting amplicons with a barcoded
primer strategy
on a 454 Genome Sequencer FLX (Roche,
Basel, Switzerland) using the manufacturers suggested protocol
for the GS-FLX-Titanium platform. We trimmed sequences of
adapter and primer sequences and removed low-quality reads as
described previously.
We further ltered low quality base calls
by applying anchor trimmingto search for conserved V5
priming regions and trimmed to these conserved regions. We
assigned Operational Taxonomic Units (OTUs) to clusters
using the UCLUST v3.0.617 de novo clustering algorithm
four percent cluster widths (96% similarity) to further minimize
OTU ination associated with pyrosequencing errors of longer
V6V4 amplicons. Eukaryotic amplicon sequencing targeted
the V9 hypervariable region and followed protocols established
in Amaral-Zettler et al. (2009).
Sequence data are deposited
in NCBIs Sequence Read Archive (SRP026054) and conform
to the Minimum Information about a MARKer gene Sequence
(MIMARKS) standard (SI Table S2).
Data Analyses and Statistical Methods. We used the R
package limma
to calculate Venn diagrams and plotted the
resulting gures using the Venn Diagram Plotter (http://ncrr. Data for subsequent analyses were resampled down
to the lowest number of reads recovered (6,102 reads) to
standardize for sampling eort. R package routines gplots and
heatmap.2 helped to generate the heatmap summary of all
OTUs that were encountered with a frequency of greater than
2% in a given sample. OTU bar graphs were generated using
Global Alignment Sequence Taxonomy (GAST) algorithms
and graphical output in QIIME v1.3.0.
We used linear
discriminant analysis (LDA) eect size (LEfSe)
to identify
biomarkers for plastics versus seawater and substrate specic
(PP vs PE vs seawater) analyses. To ascertain the closest
relative of our dominant Vibrio OTU sequence found on the C-
230 polypropylene substrate (SI Figure S2), we used the quick-
add-sequence-to-tree parsimony feature in the SILVA- 111
reference tree.
We then retained only the named type species
to summarize the result. We examined co-occurrence patterns
using network analysis and signicant linear Pearson
correlations. For the input matrices we only considered
OTUs that occurred in at least 30% of the samples. We used
Cytoscape ( to visualize the result-
Environmental Science & Technology Article |Environ. Sci. Technol. 2013, 47, 713771467138
ing network and only considered signicant correlations with
an R-value >0.9.
Identication and Selection of PMD. The majority of
plastic pieces recovered in all net tows were fragments of less
than 5 mm as has been reported in other studies.
Even the
centimeter-sized pieces chosen to extract DNA and image the
same piece with SEM were fragments without identiable
markings of undetermined origin. Pieces we examined with
SEM ranged in size from sub-mm diameter monolament
(Figure 1, piece C230_02) to at fragments that were several
cm long before subdivision (Figure 1, piece C230_01). All
showed signs of degradation including cracks and pitting as
shown in Figure 2. With the microscope-based Raman
spectrometer, most fragments collected were positively
Figure 1. Raman spectroscopy spectra of the plastics collected from the Sargasso Sea that were imaged and sequenced. The bottom scan on each
panel is of a known standard. Images along the top are light-micrographs of the plastic samples extracted for DNA analyses ((1-mm gradations; note
dierent magnication on sample C230_01).
Figure 2. SEM images showing examples of the rich microbial community on PMD: (a) pennate diatom on sample C241_07 with possible
prosthecate laments produced by Hyphomonas-like bacteria; (b) lamentous cyanobacteria on sample C230_01; (c) stalked predatory suctorian
ciliate in foreground covered with ectosymbiotic bacteria (inset) along with diatoms, bacteria, and lamentous cells on sample C230_01; (d)
microbial cells pitting the surface of sample C241_12. All scale bars are 10 μm.
Environmental Science & Technology Article |Environ. Sci. Technol. 2013, 47, 713771467139
identied as polyethylene and polypropylene based on spectra
compared to known standards (Figure 1). This was expected
since these two resins are commonly used in packaging and
other single-use plastic applications. They are also less dense
than seawater so consequently oat and accumulate in surface
The Plastisphere Community. Microscopic (phenotypic)
and molecular sequence (genotypic) data provided comple-
mentary evidence for microbial phototrophy, symbiosis,
heterotrophy (including phagotrophy), and predation in our
analyses of PP and PE PMD samples. SEM photomicrographs
revealed the presence of a rich eukaryotic and bacterial
microbiota living on both PP and PE samples (Figure 2, a
d). Cell counts of random images identied over 50 distinct
morphotypes covering between 0 and 8% of the surface area of
the plastic. Especially intriguing were round cells about 2 μmin
diameter embedded in pits in the surface of the PMD (abstract
image and Figure 2d). Often occurring in rows or patches, the
pits conform closely to the shape of the contained cells, and
included dividing cells that suggest active growth. We have not
identied these cells but they were the third most common
type of morphotype seen, after diatoms and laments. DNA
Figure 3. 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. The most abundant OTUs are listed as follows: (1) Bacteria, Verrucomicrobia, Verrucomicrobiae, Verrucomicrobiales, Rubritaleaceae,
Rubritalea; (2) Bacteria, Proteobacteria, Gammaproteobacteria, Vibrionales, Vibrionaceae, Vibrio; (3) Bacteria, Proteobacteria, Gammaproteobac-
teria, Pseudomonadales, Moraxellaceae, Psychrobacter; (4) Bacteria, Proteobacteria, Gammaproteobacteria; (5) Bacteria, Proteobacteria,
Alphaproteobacteria, Sphingomonadales, Erythrobacteraceae, Erythrobacter; (6) Bacteria, Proteobacteria, Alphaproteobacteria, Rhodobacterales,
Rhodobacteraceae, Thalassobius; (7) Bacteria, Proteobacteria, Alphaproteobacteria, Rhodobacterales, Rhodobacteraceae; (8) Bacteria,
Proteobacteria, Alphaproteobacteria, Parvularculales, Parvularculaceae, Parvularcula; (9) Bacteria, Proteobacteria, Alphaproteobacteria,
Caulobacterales, Hyphomonadaceae, Hyphomonas; (10) Bacteria, Cyanobacteria, Cyanobacteria, Subsection III, Unassigned, Phormidium; (11)
Bacteria, Cyanobacteria, Cyanobacteria, Subsection III; (12) Bacteria, Bacteroidetes, Sphingobacteria, Sphingobacteriales, Saprospiraceae, Lewinella;
(13) Bacteria, Bacteroidetes, Sphingobacteria, Sphingobacteriales, Flammeovirgaceae, Fulvivirga; (14) Bacteria, Bacteroidetes, Sphingobacteria,
Sphingobacteriales, Chitinophagaceae; (15) Bacteria, Proteobacteria, Deltaproteobacteria, Myxococcales; (16) Bacteria, Chloroexi, Anaerolineae,
Anaerolineales, Anaerolinaceae; (17) Bacteria, Bacteroidetes, Sphingobacteria, Sphingobacteriales, Saprospiraceae, Saprospira; (18) Bacteria,
Bacteroidetes, Sphingobacteria, Sphingobacteriales, Flammeovirgaceae; (19) Bacteria, Bacteroidetes, Sphingobacteria, Sphingobacteriales,
Flammeovirgaceae, Marinoscillum; (20) Bacteria, Proteobacteria, Gammaproteobacteria, Alteromonadales, Alteromonadaceae, Alteromonas; (21)
Bacteria, Proteobacteria, Alphaproteobacteria, Rhodobacterales, Rhodobacteraceae, Rhodovulum; (22) Bacteria, Proteobacteria, Gammaproteobac-
teria, Oceanospirillales, SAR86; (23) Bacteria, Proteobacteria, Gammaproteobacteria, Alteromonadales, Pseudoalteromonadaceae, Pseudoalter-
omonas; (24) Bacteria, Proteobacteria, Alphaproteobacteria, Rickettsiales, SAR116; (25) Bacteria, Proteobacteria, Alphaproteobacteria, Rickettsiales,
SAR11, Pelagibacter; (26) Bacteria, Proteobacteria, Alphaproteobacteria, Rhodospirillales, Rhodospirillaceae; (27) Bacteria, Bacteroidetes,
Sphingobacteria, Sphingobacteriales, Flammeovirgaceae, Amoebophilus; (28) Bacteria, Bacteroidetes, Sphingobacteria, Sphingobacteriales,
Chitinophagaceae, Sediminibacterium; (29) Bacteria, Bacteroidetes, Flavobacteria, Flavobacteriales, Flavobacteriaceae; (30) Bacteria, Proteobacteria,
Gammaproteobacteria, Oceanospirillales, Oceanospirillaceae, Oceaniserpentilla; (31) Bacteria, Cyanobacteria, Cyanobacteria, Subsection I,
Unassigned, Prochlorococcus; (32) Bacteria, Actinobacteria, Actinobacteria, Acidimicrobiales.
Environmental Science & Technology Article |Environ. Sci. Technol. 2013, 47, 713771467140
sequence analyses conrmed that these communities were
consistently distinct between plastics and the surrounding
seawater. For example, photosynthetic lamentous cyanobac-
teria including Phormidium and Rivularia OTUs occurred on
plastics but were absent from seawater samples where
unicellular Prochlorococcus dominated the bacterial phototroph
community in the seawater samples (Figure 3, SI Figure S1).
The presence of cyanobacteria representing Plectonema-like
genera was also evident in our SEM photomicrographs (Figure
Other conspicuous phototrophs included diatoms
(Figure 2a and background of 2b and 2c) that were assigned
to a number of bacillariophyte genera including Navicula,
Nitzschia,Sellaphora,Stauroneis, and Chaetoceros based on DNA
sequence data. The genera Navicula,Nitzschia, and Sellaphora
are commonly substrate-associated and known biolm formers
in aquatic environments.
In addition to diatoms, representa-
tive OTUs from other protists with known photosynthetic
representatives included prasinophytes, rhodophytes, crypto-
phytes, haptophytes, dinoagellates, chlorarachniophytes,
chrysophytes, pelagophytes, and phaeophytes.
While we only considered eukaryotic diversity for two of our
samples, there was corroboration between SEM images and
DNA sequence data including the stalked suctorian ciliates
(Figure 2c) covered with bacteria (Figure 2c, inset), and
sequence data conrming that one of the major ciliates was the
genus Ephelota, a marine suctorian known to colonize marine
surfaces and to harbor ectosymbiotic rod-shaped bacteria.
The relationship between the ectosymbiotic bacteria and the
Ephelota is unknown, but ectosymbiontic bacteria on the
surface of other stalked ciliates have been identied as sulde-
oxidizing Gammaproteobacteria
of the genus Thiobios, and
we identied sequences corresponding to members of the same
genus in our samples.
Surprisingly, DNA sequences derived from polycystine
colonial radiolaria were present on both plastic types and
dominated one polypropylene sample but were not identied in
our SEM imaging. The discovery of radiolarian OTUs
associated with PMD is somewhat unusual in that they are
planktonic protists that are not understood to be substrate
associated. However, there is precedence for other free-living
taxa such as planktonic foraminifera becoming associated with
Furthermore, it is highly likely that radiolarians
become passively associated with PMD both in the water
column and in our nets given that colonial forms can reach
meters in length and have a somewhat gelatinous nature. This
may also explain the presence of other traditionally free-living
taxa appearing to be associated, typically at low abundance, with
our PMD substrates (i.e., Pelagibacter,Prochlorococcus).
Heterotrophic bacteria in seawater samples were dominated
by Pelagibacter and other free-living picoplanktonic bacterial
but showed very dierent abundance patterns in the
plastics samples. A striking example was the dominance of a
member of the genus Vibrio that constituted nearly 24% of the
C230_01 polypropylene sample. This is noteworthy because
members of this genus are rarely found in concentrations
greater than 1% of the community
although members of the
species V. harveyi are a notable exception.
To the best of
our knowledge, blooms of vibrios have not been associated with
particles per se although they can dominate phytoplankton and
zooplankton surfaces.
Vibrios are also known to have
extremely fast growth rates
so this may explain their ability
to dominate members of the Plastisphere on occasion.
Based on its taxonomic placement (SI Figure S2), the Vibrio
sequence we recovered in high abundance on the poly-
propylene plastic sample C230_01 was related to the type
species of V. natriegens, a known nitrogen xer.
However, this
sequence also shared 100% identity with other nontype strain
vibrios assigned to the species V. harveyi,V. alginolyticus,V.
owensii,V. azureus,V. parahemolyticus,V. campbellii,V.
diabolicus,V. communis, and V. rotiferianus, all recent additions
to GenBank.
We are unable to assign our dominant Vibrio OTU to a
specic species based on rRNA sequence data alone so we
cannot rule out the possibility that Plastisphere microbes such
as vibrios could be animal or human pathogens. Plastic could
serve as a vector of infectious diseases since both birds and
shes ingest PMD and a recent study found shes contain
human pathogenic Vibrio strains.
Because PMD persists
longer than natural substrates (e.g., feathers, wood, and
macroalgae), it can traverse signicant distances, and it has
been shown to transport invasive species.
Harmful dino-
agellate species belonging to the genus Alexandrium were
reported from PMD in the Mediterranean,
and we also
detected several dinoagellate species including members of
this genus on our Atlantic PMD. One property that these
groups share is their propensity to adhere to surfaces. In the
case of former reports of HAB-associated PMD, the authors
specically hypothesize that it was the stickynature of the
vegetative cysts that allowed them to adhere to plastic and may
facilitate their dispersal beyond their typical range.
This nal
point reiterates the properties of PMD that set it apart from
other types of marine debris: PMD is a selective environment
with hydrophobicity that stimulates early colonizers, rapidly
driving biolm formation and succession of other microbes.
Additionally, the stimulation of microbial respiration and
growth by inert surfaces is a well-characterized phenomenon
in which dilute nutrients are concentrated creating a favorable
environment for microbial colonization.
Termed the ZoBell
eect(after Claude ZoBell who rst thoroughly described the
), this concentration of micronutrients by
abundant PMD in oligotrophic areas of the ocean could play
Figure 4. Venn diagram showing bacterial OTU overlap for pooled
PP, PE, and seawater samples; n= number of sequenced reads per
group. Numbers inside the circles represent the number of shared or
unique OTUs for a given substrate.
Environmental Science & Technology Article |Environ. Sci. Technol. 2013, 47, 713771467141
a signicant role in increasing microbial activity in the upper
layer of ocean gyres.
Alpha Diversity. Over a thousand species equivalents, or
OTUs were observed from single fragments of PE and PP (SI
Table S1). Overall, there were two notable dierences between
diversity patterns between the plastics samples and the
surrounding seawater: (1) average observed richness was
much higher in surrounding seawater; but, (2) plastic substrates
showed greater evenness than seawater, that is the community
was not dominated by a small number of abundant organisms.
It is dicult to directly compare richness between seawater and
plastics because of sample size considerations. Seawater samples
had the highest average richness and polyethylene the lowest,
but when normalized with respect to sampling eort (number
of reads recovered), the greatest richness in a single sample was
associated with polypropylene. Although the wide range of
richness values obtained from plastic pieces cautions against
drawing general conclusions about richness and plastics, we
expect richness to be related to substrate area and observed the
highest richness on the largest piece of plastic analyzed (see
image of C230_01 in Figure 1). Evenness, on the other hand,
was consistently higher on plastics (mean Simpson evenness
0.95) compared to seawater (mean Simpson 0.89) and the
brown alga Sargassum (mean Simpson 0.90) (data not shown).
In other words, seawater was characterized by many more rare
taxa that contributed to the richness in these samples.
Figure 5. Taxonomic tree generated using the LEfSe online software highlighting the biomarkers that statistically dierentiate PP, PE, and seawater
samples. Circle diameter is proportional to taxon abundance. The tree highlights both high-level (Class) and genera-specic taxonomic trends. Refer
to the legend for substrate color-coding.
Environmental Science & Technology Article |Environ. Sci. Technol. 2013, 47, 713771467142
could be due to a greater abundance of standing stock bacteria
in oligotrophic seawater, known to support a high degree of
rare taxa, partly due to lower grazing and viral pressures.
Additionally, a lower richness is expected in the more selective
and metabolically active population of bacteria on the plastic
surfaces supported by a relatively higher nutrient microenviron-
ment. The distinctness of microbial communities from PMD
was also reected in the percentage of shared OTUs across the
dierent plastic substrates (Figure 4) and Sargassum (data not
shown). Collectively we found 350 bacterial OTUs shared
between the PE and PP samples. Seawater had the largest
number of unique OTUs (n= 1789), but these were mostly
rare. Seawater shared a minor proportion of its OTUs with PE
(8.6%) and PP (3.5%), respectively. In contrast, OTUs in
common between PP and PE represented a substantial
proportion of their overall OTU assemblage with 40% of the
OTUs shared between PE and PP and 30% of the OTUs
shared between PP and PE. Therefore, Plastisphere commun-
ities, despite being quite variable, do appear to have a coreof
taxa that characterize them.
Community Membership. To further determine the
membership of the corePlastisphere community we
performed biomarker analyses.
Linear discriminant analysis
(LDA) eect size (LEfSe) revealed Plastisphere OTUs that
characterized PP and PE samples indicating plastic resins may
select for particular microbial community members. Of
particular interest were OTUs found on both plastics but not
in seawater. These included bacteria documented as capable of
degrading hydrocarbons including the lamentous cyanobacte-
rium Phormidium sp. known to settle on benthic substrates
and Pseudoalteromonas, a genus frequently associated with
marine algae
(Figure 3, SI Figure S1). Additionally, the
alphaproteobacterial family Hyphomonadaceae, known for
forming long holdfast laments termed prosthecae (which
were common in our SEM micrographs) were unique to PMD
and comprised almost 8% of the OTUs on PP (SI Figure S1).
Members of the Hyphomonadaceae can be methylotrophic,
known to degrade hydrocarbons and present in hydrocarbon
Figure 5 summarizes the biomarker results
and highlights the dierences between each plastic substrate
and seawater. LDA scores are shown in SI Figure S3.
Network Analyses. We can make inferences about
organism associations from SEM observations of physical
location and community architecture on the plastic surface.
Although many bacteria cannot be identied visually, it is
possible to infer interactions between members of the
Plastisphere indirectly via association networks based on
sequence data.
We conducted network analyses to further
explore co-occurrence patterns between members of the
Plastisphere. Reporting all existing networks is beyond the
scope of this paper, so we present only networks associated
with putative hydrocarbon-degrading bacteria within our overall
network. Figure 6 depicts these networks with the cyanobacte-
rium Phormidium highlighted as green diamonds, Hyphomonas
as blue diamonds, members of the Chloroexi as purple
hexagons and members of the Myxococcales as yellow triangles.
The gure only depicts rst nearest neighbors in the network
with positive correlations having R> 0.9. Noteworthy were the
co-occurrences of several members of putative hydrocarbon
degrading taxa in close proximity to each other in our network.
Figure 6. Network analysis diagram of putative hydrocarbon degrading bacterial OTUs. The cyanobacterium Phormidium is represented in green
diamonds, Hyphomonas is depicted in blue diamonds, members of the Chloroexi are shown in purple hexagons and members of the Myxococcales
are represented as yellow triangles. SI Table S3 includes the full taxonomy for all the OTUs in the network.
Environmental Science & Technology Article |Environ. Sci. Technol. 2013, 47, 713771467143
In addition to the four aforementioned main groups, we further
detected other potential hydrocarbon-degrading OTUs that
were their nearest neighbors. These included Hyphomonas-
associated OTUs such as Haliscomenobacter (OTU C507,
C300, C2094), associated with hydrocarbon contaminated
Devosia (OTU C137) associated with diesel-contami-
nated soils
and Oceaniserpentilla (OTU 1470), one the of
major taxa related to OTUs from the Deepwater Horizon oil
While the presence of these taxa alone does not
implicate them in plastic degradation, our network analyses
suggests that consortia of OTUs may be acting in concert to
utilize this recalcitrant carbon source and provides a testable
hypothesis for future investigation.
PMD age and fate are poorly characterized; despite dramatic
increases in plastic production, a 22-year study in the North
Atlantic Subtropical Gyre showed no evidence of increasing
quantities of PMD collected with a neuston net (333 μm
implying there must be unrecognized sinks to balance
the sources. A recent review by Hidalgo-Ruz et al.
much of what is known about PMD and emphasizes the need
for further study of how abiotic and biotic factors break it
down. Our SEM images show microbial cells embedded in pits
in the plastic surface, suggesting that microbes may be taking
part in the degradation of plastic via physical or metabolic
means (Figure 2d and abstract). These types of cells were
found on both PE and PP, and include dividing cells (see image
in abstract). Bacteria and fungi are known to degrade refractile
compounds including plastic
but this has not been
demonstrated in the open ocean. The pits visualized in PMD
surfaces that conform to the shape of cells growing in the pits,
and sequences of known hydrocarbon degraders support the
possibility that some members of the Plastisphere community
are hydrolyzing PMD and could accelerate physical degrada-
tion. Future research directions include understanding the
genetic mechanisms of how microbes attach to PMD and
elucidating the microbes and genes involved in microbially
mediated plastic degradation through assaying our extensive
culture collection, as well as exploring how these processes
inuence interactions with larger organisms.
SSupporting Information
Figure S1 shows a heatmap with the relative abundances of the
most abundant taxonomic groups from PP, PE and seawater.
Figure S2 shows an ARB tree with the placement of our most
abundant Vibrio OTU. Figure S3 shows the LDA scores for the
OTUs that explain the greatest dierences between seawater,
PP and PE communities. Table S1 provides contextual data for
the samples used in this study including observed richness and
evenness. Table S2 provides a MIMARKS table. Table S3
provides the taxonomy for the network analysis shown in
Figure 6.This material is available free of charge via the Internet
Corresponding Author
*Phone: 508-289-7259 (L.A.A.-Z.); 508-289-3640 (T.J.M.).
Fax: 508-457-4727 (L.A.A.-Z.); 508-289-3640 (T.J.M.). E-mail: (L.A.A.-Z.);
Author Contributions
All authors contributed equally to this work.
The authors declare no competing nancial interest.
We thank Giora Proskurowski for discussions and collecting
samples under NFWF-NOAA Marine Debris Program Award
No. 2009-0062-002, Amy Siuda for collecting samples, and
Emelia Deforce, Greg Boyd, Sonja Uribe and Catherine Stark
for technical assistance. This work was supported by an NSF
Collaborative grant to E.R.Z. (OCE-1155379), T.J.M. (OCE-
1155671) and L.A.A-Z. (OCE-1155571), NSF TUES grant to
E.R.Z. and L.A.A.-Z. (DUE-1043468), and was partially funded
by the Woods Hole Center for Oceans and Human Health
Pilot award (No. 26291503) to T.J.M.
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... The composition and functional capacity of the plastisphere (the microbial community found on plastic pollution; Zettler et al., 2013) is influenced by the size and chemical composition of plastics and the surrounding environment (Tu et al., 2020). Micro-and nano-plastics are not necessarily found as independently-floating particles in the environment, but rather can agglomerate and form larger particulate material, somewhat akin marine snow (Summers et al., 2018), becoming readily available for consumption by small organisms and filter feeders (see Section 3.4.1). ...
... Microbial colonization is enabled by the initial adsorption of various organic molecules to the plastic surface, forming an ecocorona (Galloway et al., 2017;Lynch et al., 2014), which provides an additional source of carbon and energy and drives the initial attachment of microorganisms ( Fig. 1f; Galloway et al., 2017;Rahman et al., 2021;Wright et al., 2020). While there have been numerous studies exploring the composition and diversity of biofilms on various types of plastics (Delacuvellerie et al., 2019;Dussud et al., 2018;McCormick et al., 2016;Miao et al., 2019;Oberbeckmann et al., 2018;Zettler et al., 2013), few studies have focused on the ecological functions of these microorganisms (Amaral-Zettler et al., 2020), and even fewer studies have been conducted in Southeast Asia. A recent study conducted in the Maludam River, Malaysia identified different gene expression profiles among communities present on microplastics from those expressed in the surrounding waters, including key genes involved in carbon, nitrogen, and sulphur cycling (Rahman et al., 2021). ...
Southeast Asia is considered to have some of the highest levels of marine plastic pollution in the world. It is therefore vitally important to increase our understanding of the impacts and risks of plastic pollution to marine ecosystems and the essential services they provide to support the development of mitigation measures in the region. An interdisciplinary, international network of experts (Australia, Indonesia, Ireland, Malaysia, the Philippines, Singapore, Thailand, the United Kingdom, and Vietnam) set a research agenda for marine plastic pollution in the region, synthesizing current knowledge and highlighting areas for further research in Southeast Asia. Using an inductive method, 21 research questions emerged under five non-predefined key themes, grouping them according to which: (1) characterise marine plastic pollution in Southeast Asia; (2) explore its movement and fate across the region; (3) describe the biological and chemical modifications marine plastic pollution undergoes; (4) detail its environmental, social, and economic impacts; and, finally, (5) target regional policies and possible solutions. Questions relating to these research priority areas highlight the importance of better understanding the fate of marine plastic pollution, its degradation, and the impacts and risks it can generate across communities and different ecosystem services. Knowledge of these aspects will help support actions which currently suffer from transboundary problems, lack of responsibility, and inaction to tackle the issue from its point source in the region. Being profoundly affected by marine plastic pollution, Southeast Asian countries provide an opportunity to test the effectiveness of innovative and socially inclusive changes in marine plastic governance, as well as both high and low-tech solutions, which can offer insights and actionable models to the rest of the world.
... (w/w) (Carson et al., 2011;Seeley et al., 2020). MPs contamination in estuarine regions is becoming even more serious owing to the continuously rising populations and plastics production (Andrady, 2017), thus raising a global concern (Zettler et al., 2013). However, the ecological risks of MPs in estuarine ecosystems have not been well understood. ...
... 5e and S6a). Although complex microbial communities lead to various degrading extents of plastics in the marine environment (Zettler et al., 2013;Andrady, 2017), other researchers have suggested that biodegradation of plastics is low (Yu et al., 2022). Thus, longer duration experiments are required to explore whether bacteria can degrade plastic over time when facing a labile sediment C limitation . ...
Increasing microplastics (MPs) pollution in estuaries profoundly impacts microbial ecosystems and biogeochemical processes. Nitrous oxide (N2O), a powerful greenhouse gas, is an important intermediate product of microbial nitrogen cycling. However, how MPs regulate N2O production and its pathways remain poorly understood. Here, impacts of traditional petroleum-based and emerging biodegradable MPs on microbial N2O production and its pathways were studied through dual-isotope (15N–18O) labeling technique and molecular methods. Results indicated that both traditional petroleum-based and emerging biodegradable MPs promoted sedimentary N2O production, whereas pathways varied. Biodegradable polylactic acid (PLA) MPs displayed greater promotion of N2O production than petroleum-based MPs, polyvinyl chloride (PVC) and polyethylene (PE), of which PLA promoted through nitrifier nitrification (NN) and heterotrophic denitrification (HD), PE through nitrifier denitrification and HD, and PVC through NN. By combining the analysis of N2O production rates with sediment chemical and microbiological properties, we demonstrated that the enrichment of nitrifying and denitrifying bacteria, as well as related functional genes directly and/or indirectly increased N2O production primarily by interacting with carbon and nitrogen substrates. Different response of nitrogen cycling microbes to MPs led to the difference in N2O increase pathways, of which nitrifying bacteria significantly enriched in all MPs treatments due to the niches provided by MPs. However, part of denitrifying bacteria significantly enriched in treatments containing PLA and PE MPs, which may serve as organic carbon substrates. This work highlights that the presence of MPs can promote sedimentary N2O production, and the emerging biodegradable MPs represented by PLA may have a greater potential to enhance estuarine N2O emissions and accelerate global climate change.
... The period of sample immersion in seawater was more important in shaping biofouling assemblages than the concentration of oyster shell filler, as evidenced by finding similar biological communities between oyster shell-enriched substrates and controls. Most studies that have reported plastic-specific recruitment (Zettler et al., 2013;Oberbeckmann et al., 2018;Hou et al., 2021;Martıńez-Campos et al., 2021) have focused on a variety of chemically-distinct polymers (e.g., polystyrene, polyethylene, and polypropylene). Our experiment used the same base polymer (PBS) to manufacture control and treatment substrates. ...
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Impacts of Marine Plastic Debris (MPD) on marine ecosystems are among the most critical environmental concerns of the past three decades. Virgin plastic is often cheaper to manufacture than recycled plastics, increasing rates of plastic released into the environment and thereby impacting ecosystem health and functioning. Along with other environmental effects, MPD can serve as a vector for marine hitchhikers, facilitating unwanted organisms' transport and subsequent spread. Consequently, there is a growing demand for more eco-friendly replacements of conventional plastic polymers, ideally with fit-for-purpose properties and a well-understood life cycle. We enriched polybutylene succinate (PBS) with three different concentrations of oyster shell to investigate the dynamics of biofouling formation over 18 weeks at the Nelson Marina, Aotearoa/New Zealand. Our study focused on oyster shell concentration as a determinant of fouling assemblages over time. While generally considered as a waste in the aquaculture sector, we used oyster shells as a variable of interest to investigate their potential for both, environmental and economic benefits. Using bacterial 16S and eukaryotic 18S rRNA gene metabarcoding, our results revealed that following immersion in seawater, time played a more critical role than substrate type in driving biofouling community structures over the study period. In total, 33 putative non-indigenous species (NIS) and 41 bacterial families with putative plastic-degrading capability were detected on the different substrates. Our analysis of NIS recruitment revealed a lower contribution of NIS on shell-enriched substrates than unadulterated polymers samples. In contrast, the different concentrations of oyster shells did not affect the specific recruitment of bacterial degraders. Taken together, our results suggest that bio-based polymers and composites with increased potential for biodegradability, recyclability, and aptitude for the selective recruitment of marine invertebrates might offer a sustainable alternative to conventional polymers, assisting to mitigate the numerous impacts associated with MPD.
... Other concerns of waste plastic in the ecological system are the transport and possible concentration of contaminants by waste plastic which is subtler. Additionally, monitoring of ecological and human health impacts is more in the marine environment than on land where all the waste plastics are generated and transported to the water bodies (Zettler et al. 2013) With these challenges, this current study made a salient contribution towards the conversion of waste plastic to green-efficient construction material without negative impact on ecological and microclimate. ...
The level of generated plastic waste has awash over a billion metric tonnes of this waste into our environment. If an effective long-lasting solution to this impending disaster is not provided through recycling, reengineering, and conversion of this waste to resourceful materials. Then sustainability and conservation of natural non-replenishable materials will be severely threatened. The aims to avert the impending consequences of this disaster and conserve natural materials have given rise to a sustainable future in the production of low carbon embedded construction materials. Under these circumstances, this study, therefore, presents the strengths and durability of waste plastic bricks (WPB) produced from blending scrap PET plastics and foundry sand. The WPB masonry bricks were produced using ratios of 10:90, 20: 80, and 30: 70 to the combined dry mass of PET and sand. Series of compressive strength tests, modulus of rupture (MOR) tests, apparent porosity tests, water absorption tests, salt-resistance tests, ultrasonic pulse velocity, and scanning electron microscopy (SEM) tests were conducted to investigate the strength and durability of the WPB in conformance with the South African National Standard (SANS 227) for individual load-bearing masonry face brick unit. Compared to the clay bricks with 18 MPa what of strength, the test result revealed that the WPB rendered an average compressive strength of 35.2 MPa. Furthermore, the test result showed that the WPB recorded significant strength resistance under tension compared to the clay brick due to the ductility properties of scrap plastic waste. Also, the acid effects were significantly resisted on the surface WPBs due to the hydrophobic property of the PET- waste. The stiffness of the clay bricks portrayed brittle response, whereas WPBs benefited with high ductility properties, therefore, revealed a great proportionality between the dynamic modulus and ultrasonic pulse velocity (UPV) with a coefficient of determination (R2) of 90%.
... Plastics of polystyrene (PS), polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), and so on are today not only extremely versatile, but also the most-produced polymer materials worldwide [1,2]. These polymers have been introduced as significant components for specific manufacturing processes due to their unique properties of cost-effectiveness, flexible shaping, and long-lasting robustness. ...
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Micro(nano)plastic (MNP) pollutants have not only impacted human health directly, but are also associated with numerous chemical contaminants that increase toxicity in the natural environment. Most recent research about increasing plastic pollutants in natural environments have focused on the toxic effects of MNPs in water, the atmosphere, and soil. The methodologies of MNP identification have been extensively developed for actual applications, but they still require further study, including on-site detection. This review article provides a comprehensive update on the facile detection of MNPs by Raman spectroscopy, which aims at early diagnosis of potential risks and human health impacts. In particular, Raman imaging and nanostructure-enhanced Raman scattering have emerged as effective analytical technologies for identifying MNPs in an environment. Here, the authors give an update on the latest advances in plasmonic nanostructured materials-assisted SERS substrates utilized for the detection of MNP particles present in environmental samples. Moreover, this work describes different plasmonic materials-including pure noble metal nanostructured materials and hybrid nanomaterials-that have been used to fabricate and develop SERS platforms to obtain the identifying MNP particles at low concentrations. Plasmonic nanostructure-enhanced materials consisting of pure noble metals and hybrid nanomaterials can significantly enhance the surface-enhanced Raman scattering (SERS) spectra signals of pollutant analytes due to their localized hot spots. This concise topical review also provides updates on recent developments and trends in MNP detection by means of SERS using a variety of unique materials, along with three-dimensional (3D) SERS substrates, nanopipettes, and microfluidic chips. A novel material-assisted spectral Raman technique and its effective application are also introduced for selective monitoring and trace detection of MNPs in indoor and outdoor environments. Graphical abstract:
... Microplastics enter aquatic ecosystems, and the bacteria from the surrounding environment could selectively colonize and propagate on the microplastic surface, forming a new microbial ecological niche (7,10,43,44). This study found that the a-diversity of bacterial communities on microplastics from the Three Gorges Reservoir area was lower than that in sediment, but there was no significant difference from that in water. ...
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In river systems, microplastics create new microbial niches that significantly differ from those of the surrounding environment. However, the potential relationships between the biogeographic distribution and assembly processes of microbial communities on microplastics were still not well understood.
It is undeniable that plastics are ubiquitous and a threat to global ecosystems. Plastic waste is transformed into microplastics (MPs) through physical and chemical disruption processes within the aquatic environment. MPs are detected in almost every environment due to their worldwide transportability through ocean currents or wind, which allows them to reach even the most remote regions of our planet. MPs colonized by biofilm-forming microbial communities are known as the ''plastisphere". The revelation that this unique substrate can aid microbial dispersal has piqued interest in the ground of microbial ecology. MPs have synergetic effects on the development, transportation, persistence, and ecology of microorganisms. This review summarizes the studies of plastisphere in recent years and the microbial community assemblage (viz. autotrophs, heterotrophs, predators, and pathogens). We also discussed plastic-microbe interactions and the potential sources of plastic degrading microorganisms. Finally, it also focuses on current technologies used to characterize those microbial inhabitants and recommendations for further research.
This study evaluates the toxicity of pristine (Unwashed) and aged, clean (Biofilm-) or fouled (Biofilm+), PS microspheres (3 μm,10 μm), using Washed particles as a reference material, on selective and continuous larval culture of Amphibalanus amphitrite. Exposure to 3 μm Unwashed and Biofilm+ particles for 24h induced significant mortality (60% and 57% respectively) in stage II larvae. Stage II and VI nauplii showed greater uptake of 3 μm Biofilm- particles. Accumulative exposure to microplastics in continuous larval culture significantly affected the naupliar survival, particularly of stage III and IV. Cumulative mortality was >70% after exposure to 3 μm Unwashed and 10 μm Biofilm+ particles. Unwashed particles with increasing concentration and aged particles with increasing size, delayed the development of nauplii to cyprids. Though,>50% cyprids showed successful settlement however the highest concentration of 3 μm Biofilm+ microspheres inhibited the settlement and induced precocious metamorphosis in 9% of the cyprids.
Lack of degradability and the accumulation of polymeric wastes increase the risk for the health of the environment. Recently, recycling of polymeric waste materials becomes increasingly important as raw materials for polymer synthesis are in short supply due to the rise in price and supply chain disruptions. As an important polymer, polyurethane (PU) is widely used in modern life, therefore, PU biodegradation is desirable to avoid its accumulation in the environment. In this study, we isolated a fungal strain Cladosporium halotolerans from the deep sea which can grow in mineral medium with a polyester PU (Impranil DLN) as a sole carbon source. Further, we demonstrate that it can degrade up to 80% of Impranil PU after 3 days of incubation at 28 ℃ by breaking the carbonyl groups (1732 cm-1) and C-N-H bonds (1532 cm-1 and 1247 cm-1) as confirmed by Fourier-transform infrared (FTIR) spectroscopy analysis. Gas chromatography-mass spectrometry (GC-MS) analysis revealed polyols and alkanes as PU degradation intermediates, indicating the hydrolysis of ester and urethane bonds. Esterase and urease activities were detected in 7 days-old cultures with PU as a carbon source. Transcriptome analysis showed a number of extracellular protein genes coding for enzymes such as cutinase, lipase, peroxidase and hydrophobic surface binding proteins A (HsbA) were expressed when cultivated on Impranil PU. The yeast two-hybrid assay revealed that the hydrophobic surface binding protein ChHsbA1 directly interacts with inducible esterases, ChLip1 (lipase) and ChCut1 (cutinase). Further, the KEGG pathway for "fatty acid degradation" was significantly enriched in Impranil PU inducible genes, indicating that the fungus may use the degradation intermediates to generate energy via this pathway. Taken together, our data indicates secretion of both esterase and hydrophobic surface binding proteins by C. halotolerans plays an important role in Impranil PU absorption and subsequent degradation. Our study provides a mechanistic insight into Impranil PU biodegradation by deep sea fungi and provides the basis for future development of biotechnological PU recycling.
The daily use of plastics presents a serious pollution issue due to their extremely slow degradation. Microplastics and the biofilm that grows on plastics (i.e., the plastisphere) are important subsets of plastic wastes. Many studies have been conducted to reveal the structures of the plastispheres, the driving factors for the formation of the plastisphere, and the ability of the plastispheres to degrade plastics in a variety of water bodies. However, the plastispheres related to wastewater are understudied. In this study, we used a microcosmic strategy to study the evolution of the plastispheres associated with microplastics (MPs) over time in wastewater. We found that plastic materials and water sources did not actively select and shape the plastispheres at an early stage, but the active selection for a unique niche of the plastisphere occurred after 14 d of growth. In addition, we confirmed that the alkB gene was densely present, and metagenomics showed some additional chemical reactions, which suggests that MPs are consumed by the microbes in the plastispheres. Additionally, metagenomics identified some metagenome-assembled genomes (MAGs) associated with high-density polyethylene (HDPE) and polyethylene terephthalate (PET). The identification of HDPE-associated MAGs and PET-associated MAGs further supports the notion that the selection for a unique niche of the plastisphere is driven by plastic materials and water sources (in this study, after 14 d of growth). Our discoveries bring new views on the behavior of the wastewater-associated plastisphere, especially how long it takes a wastewater plastisphere to form.
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Microbes have central roles in ocean food webs and global biogeochemical processes, yet specific ecological relationships among these taxa are largely unknown. This is in part due to the dilute, microscopic nature of the planktonic microbial community, which prevents direct observation of their interactions. Here, we use a holistic (that is, microbial system-wide) approach to investigate time-dependent variations among taxa from all three domains of life in a marine microbial community. We investigated the community composition of bacteria, archaea and protists through cultivation-independent methods, along with total bacterial and viral abundance, and physico-chemical observations. Samples and observations were collected monthly over 3 years at a well-described ocean time-series site of southern California. To find associations among these organisms, we calculated time-dependent rank correlations (that is, local similarity correlations) among relative abundances of bacteria, archaea, protists, total abundance of bacteria and viruses and physico-chemical parameters. We used a network generated from these statistical correlations to visualize and identify time-dependent associations among ecologically important taxa, for example, the SAR11 cluster, stramenopiles, alveolates, cyanobacteria and ammonia-oxidizing archaea. Negative correlations, perhaps suggesting competition or predation, were also common. The analysis revealed a progression of microbial communities through time, and also a group of unknown eukaryotes that were highly correlated with dinoflagellates, indicating possible symbioses or parasitism. Possible ‘keystone’ species were evident. The network has statistical features similar to previously described ecological networks, and in network parlance has non-random, small world properties (that is, highly interconnected nodes). This approach provides new insights into the natural history of microbes.
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The oceanic convergence zone in the North Pacific Subtropical Gyre acts to accumulate floating marine debris, including plastic fragments of various sizes. Little is known about the ecological consequences of pelagic plastic accumulation. During the 2009 Scripps Environmental Accumulation of Plastics Expedition (SEAPLEX), we investigated whether mesopelagic fishes ingest plastic debris. A total of 141 fishes from 27 species were dissected to examine whether their stomach contents contained plastic particles. The incidence of plastic in fish stomachs was 9.2%. Net feeding bias was evaluated and judged to be minimal for our methods. The ingestion rate of plastic debris by mesopelagic fishes in the North Pacific is estimated to be from 12 000 to 24 000 tons yr–1. Similar rates of plastic ingestion by mesopelagic fishes may occur in other subtropical gyres.
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Two poorly known marine suctorian ciliates, Ephelota truncata Fraipont, 1878 and Ephelota mammillata Dons, 1918, collected from the coastal waters off Qingdao, China, were investigated using both live observations and protargol impregation methods. Improved diagnoses for both species are supplied based on previous and current studies. The adult form of each species has two types of tentacle, a long stalk and a ramose macronucleus. In addition, E. truncata has a short column-shaped body about 75–250 × 100–200 µm in vivo, 12–16 suctorial tentacles, 80–100 prehensile tentacles and a stalk that is 500–1200 µm long; the swarmer is ovoid, about 40 × 30 µm in vivo, with 19–24 somatic kineties and a C-shaped macronucleus. E. mammillata has a bowl-shaped body about 55–150 × 80–150 µm in vivo, ca. 10 suctorial tentacles, 30–50 prehensile tentacles and a stalk that is 350–800 µm long. The SSU rRNA genes were sequenced for both species in order to compare them with those of closely related congeners.. In terms of species identification, Ephelota is one of the most confused genera of suctorians. There are two main reasons for this: firstly many of the morphological fea-tures used in species descriptions overlap, and secondly the vast majority of species descriptions are based only on in vivo observations with comparatively few having been described using silver staining or other modern methods (Guilcher 1951, Chen et al. 2008).
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Macroscopic observations of floating plastic debris collected at several places along the Catalan coast (northwestern Mediterranean) showed conspicuous green-yellow patches adhered to them. The microscopic examination of these patches showed that they were constituted mainly of benthic diatoms and small flagellates ( Ostreopsis sp. and Coolia sp., resting cysts of unidentified dinoflagellates and both temporary cysts and vegetative cells of Alexandrium taylori were also found. Plastic debris is considered to be one of the most serious problems affecting the marine environment. We suggest drifting plastic debris as a potential vector for microalgae dispersal.
Phormidium foveolarum can absorb and degrade N-tetradecane. Under dark conditions, O2 consumption increases with the reaction time for hydrocarbon degradation. -from English summary
Entanglement, ingestion, and ghost-fishing are well-documented biologically damaging effects of marine debris. Debris may also smother benthic communities on soft and hard bottoms (Parker 1990). For a number of organisms, however, plastic debris provides a positive opportunity, creating new habitats in the form of numerous, semipermanent floating islands, which are driven by winds and currents around the world’s oceans. Although these epibiotic assemblages seem to be most common in warm-water regions, biologically encrusted plastic items have already been found at sites ranging from the Subantarctic to the Equator (Gregory et al. 1984; Gregory 1990a, 1990b). This paper focuses on studies by the three authors at sites in the Western Atlantic and the Southern Pacific, with findings of worldwide relevance.
Rationale for Clustering Caulobacter, Asticcacaulis, Hyphomicrobium, Pedomicrobium, Hyphomonas and ThiodendronThe genera treated together here comprise the dimorphic prosthecate bacteria (DPB), in which reproduction regularly results in the separation of two cells that are morphologically and behaviorally different from each other (Fig. 1). One sibling is nonmotile and prosthecate, possessing at least one elongated, cylindrical appendage that is an outgrowth of the cell surface, including the outer membrane, the peptidoglycan layer, and the cell membrane, and that may also include cytoplasmic elements such as ribosomes; such an appendage is a prostheca (Staley, 1968). In natural populations, this prosthecate cell is usually also sessile by virtue of adhesive material associated with a cell pole or with the prostheca. The other sibling is flagellated, bearing (typically) one pol ...
To evaluate the incidence of ocean-borne plastic particle ingestion by western North Atlantic seabirds, we analyzed the gut contents of 1033 birds collected off the coast of North Carolina from 1975-1989. Twenty-one of 38 seabird species (55%) contained plastic particles. Procellariiform birds contained the most plastic and the presence of plastic was clearly correlated with feeding mode and diet. Plastic ingestion by procellariiforms increased over the 14 year study period, probably as a result of increasing plastic particle availability. Some seabirds showed a tendency to select specific plastic shapes and colors, indicating that they may be mistaking plastics for potential prey items. We found no evidence that seabird health was affected by the presence of plastic, even in species containing the largest quantities: Northern Fulmars (Fulmarus glacialis), Red Phalaropes (Phalaropus fulicaria) and Greater Shearwaters (Puffinus gravis).