Identification of the bacterial community that degrades phenanthrene sorbed to polystyrene nanoplastics using DNA-based stable isotope probing.

In the Anthropocene, plastic pollution has become a new environmental biotope, the so-called plastisphere. In the oceans, nano- and micro-sized plastics are omnipresent and found in huge quantities throughout the water column and sediment, and their large surface area-to-volume ratio offers an excellent surface to which hydrophobic chemical pollutants (e.g. petrochemicals and POPs) can readily sorb to. Our understanding of the microbial communities that breakdown plastic-sorbed chemical pollutants, however, remains poor. Here, we investigated the formation of 500 nm and 1000 nm polystyrene (PS) agglomerations in natural seawater from a coastal environment, and we applied DNA-based stable isotope probing (DNA-SIP) with the 500 nm PS sorbed with isotopically-labelled phenanthrene to identify the bacterial members in the seawater community capable of degrading the hydrocarbon. Whilst we observed no significant impact of nanoplastic size on the microbial communities associated with agglomerates that formed in these experiments, these communities were, however, significantly different to those in the surrounding seawater. By DNA-SIP, we identified Arcobacteraceae, Brevundimonas, Comamonas, uncultured Comamonadaceae, Delftia, Sphingomonas and Staphylococcus, as well as the first member of the genera Acidiphilum and Pelomonas to degrade phenanthrene, and of the genera Aquabacterium, Paracoccus and Polymorphobacter to degrade a hydrocarbon. This work provides new information that feeds into our growing understanding on the fate of co-pollutants associated with nano- and microplastics in the ocean.

RNA is a key component of extracellular DNA networks in Pseudomonas aeruginosa biofilms.

The extracellular matrix of bacterial biofilms consists of diverse components including polysaccharides, proteins and DNA. Extracellular RNA (eRNA) can also be present, contributing to the structural integrity of biofilms. However, technical difficulties related to the low stability of RNA make it difficult to understand the precise roles of eRNA in biofilms. Here, we show that eRNA associates with extracellular DNA (eDNA) to form matrix fibres in Pseudomonas aeruginosa biofilms, and the eRNA is enriched in certain bacterial RNA transcripts. Degradation of eRNA associated with eDNA led to a loss of eDNA fibres and biofilm viscoelasticity. Compared with planktonic and biofilm cells, the biofilm matrix was enriched in specific mRNA transcripts, including lasB (encoding elastase). The mRNA transcripts colocalised with eDNA fibres in the biofilm matrix, as shown by single molecule inexpensive FISH microscopy (smiFISH). The lasB mRNA was also observed in eDNA fibres in a clinical sputum sample positive for P. aeruginosa. Thus, our results indicate that the interaction of specific mRNAs with eDNA facilitates the formation of viscoelastic networks in the matrix of Pseudomonas aeruginosa biofilms.

Effect of ocean acidification on the growth, response and hydrocarbon degradation of coccolithophore-bacterial communities exposed to crude oil.

Hydrocarbon-degrading bacteria, which can be found living with eukaryotic phytoplankton, play a pivotal role in the fate of oil spillage to the marine environment. Considering the susceptibility of calcium carbonate-bearing phytoplankton under future ocean acidification conditions and their oil-degrading communities to oil exposure under such conditions, we investigated the response of non-axenic E. huxleyi to crude oil under ambient versus elevated CO2 concentrations. Under elevated CO2 conditions, exposure to crude oil resulted in the immediate decline of E. huxleyi, with concomitant shifts in the relative abundance of Alphaproteobacteria and Gammaproteobacteria. Survival of E. huxleyi under ambient conditions following oil enrichment was likely facilitated by enrichment of oil-degraders Methylobacterium and Sphingomonas, while the increase in relative abundance of Marinobacter and unclassified Gammaproteobacteria may have increased competitive pressure with E. huxleyi for micronutrient acquisition. Biodegradation of the oil was not affected by elevated CO2 despite a shift in relative abundance of known and putative hydrocarbon degraders. While ocean acidification does not appear to affect microbial degradation of crude oil, elevated mortality responses of E. huxleyi and shifts in the bacterial community illustrates the complexity of microalgal-bacterial interactions and highlights the need to factor these into future ecosystem recovery projections.

Marine Sponges in a Snowstorm - Extreme Sensitivity of a Sponge Holobiont to Marine Oil Snow and Chemically Dispersed Oil Pollution.

Holobionts formed by a host organism and associated symbionts are key biological units in marine ecosystems where they are responsible for fundamental ecosystem services. Therefore, understanding anthropogenic impacts on holobionts is essential. Sponges (Phylum Porifera) are ideal holobiont models. They host a complex microbial community and provide ecosystem services including nutrient cycling. At bathyal depths, sponges can accumulate forming dense sponge ground habitats supporting biodiverse associated communities. However, the impacts of spilled oil and dispersants on sponge grounds cannot be understood without considering exposures mediated through sponge filtration of marine snow particles. To examine this, we exposed the model sponge Halichondria panicea to oil, dispersant and "marine oil snow" contaminated seawater and elucidate the complex molecular response of the holobiont through metatranscriptomics. While the host response included detoxification and immune response pathways, the bacterial symbiotic response differed and was at least partially the result of a change in the host environment rather than a direct response to hydrocarbon exposure. As the sponge host reduced its pumping activity and internal tissue oxygen levels declined, the symbionts changed their metabolism from aerobic to anaerobic pathways possibly via quorum sensing. Furthermore, we found evidence of hydrocarbon degradation by sponge symbionts, but sponge mortality (even when exposed to low concentrations of hydrocarbons) implied this may not provide the holobiont with sufficient resilience against contaminants. Given the continued proposed expansion of hydrocarbon production into deep continental shelf and slope settings where sponge grounds form significant habitats it is important that dispersant use is minimised and that environmental impact assessments carefully consider the vulnerability of sponge holobionts.

Bacterial biofilm colonization and succession in tropical marine waters are similar across different types of stone materials used in seawall construction.

Seawalls are important in protecting coastlines from currents, erosion, sea-level rise, and flooding. They are, however, associated with reduced biodiversity, due to their steep orientation, lack of microhabitats, and the materials used in their construction. Hence, there is considerable interest in modifying seawalls to enhance the settlement and diversity of marine organisms, as microbial biofilms play a critical role facilitating algal and invertebrate colonization. We assessed how different stone materials, ranging from aluminosilicates to limestone and concrete, affect biofilm formation. Metagenomic assessment of marine microbial communities indicated no significant impact of material on microbial diversity, irrespective of the diverse surface chemistry and topography. Based on KEGG pathway analysis, surface properties appeared to influence the community composition and function during the initial stages of biofilm development, but this effect disappeared by Day 31. We conclude that marine biofilms converged over time to a generic marine biofilm, rather than the underlying stone substrata type playing a significant role in driving community composition.

A Practical Approach for Primary Care Practitioners to Evaluate and Manage Lower Urinary Tract Symptoms and Benign Prostatic Hyperplasia.

BACKGROUND: Benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS) are common clinical encounters for most primary care practitioners (PCPs). More than 50% of men aged > 50 years will develop significant lower urinary tract symptoms. Managing these symptoms can be complicated and requires an informed discussion between the PCP and the patient. This article provides a comprehensive review for PCPs regarding the evaluation and management of LUTS in men and when to consider a urology referral. OBSERVATIONS: Over the past 3 decades, medications have become the most common BPH and LUTS therapy, but recently, newer minimally invasive surgeries have challenged this paradigm. PCPs are in a unique position to help many patients who present with early stage LUTS. CONCLUSIONS: A clear understanding of the available treatment options will help PCPs counsel patients appropriately about lifestyle modification, medications, and surgical treatment options for their symptoms.

Male Voiding Behavior: Insight from 19,824 At-Home Uroflow Profiles.

PURPOSE: Benign prostatic hyperplasia is one of the most common conditions seen by a general urologist. Validated questionnaires provide insight into patient symptoms, however office based uroflow devices are limited by the variability of voiding behavior. Using a home uroflow device, we assessed individual voiding variability, temporal distribution of voiding parameters and the impact of age on voiding. MATERIALS AND METHODS: Between April 2019 and June 2020, 19,824 unique voiding profiles were captured using the Stream Dx Uroflowmeter and retrospectively analyzed. Age and number of voids were summarized by mean±standard deviation. We used mixed effects models to compare average values and intrapatient variability of voiding parameters to time of day and age. The coefficient of variation was used to assess intrapatient variability. RESULTS: A total of 637 patients were identified with 625 meeting inclusion criteria, producing 19,824 voids. Mean age was 67 (±10.2) years old, and each patient provided on average 5 (±3.3) voids a day through 7 days. Average intrapatient voiding parameters showed notable variability, where the coefficient of variation for maximum flow was 27.6% (95% CI 26.6-28.6). Early morning voids were associated with higher volume and lower number of voids. As age progressed, voiding profiles worsened in a linear fashion. Afternoon and evening voids were associated with reduced intrapatient variability relative to early morning voids. CONCLUSIONS: Assessment of 19,824 uroflows using an accurate and precise home uroflow device demonstrates that an individual's voiding parameters vary greatly from day to day, throughout the day, and worsen with age. Multiple measurements performed at home provides a more realistic assessment of true voiding behavior by capturing individual voiding variability and can help urologists make better decisions in patient care.

Hydrocarbon-Degrading Bacteria Found Tightly Associated with the 50-70 µm Cell-Size Population of Eukaryotic Phytoplankton in Surface Waters of a Northeast Atlantic Region.

The surface of marine eukaryotic phytoplankton can harbour communities of hydrocarbon-degrading bacteria; however, this algal-bacterial association has, hitherto, been only examined with non-axenic laboratory cultures of micro-algae. In this study, we isolated an operationally-defined community of phytoplankton, of cell size 50-70 µm, from a natural community in sea surface waters of a subarctic region in the northeast Atlantic. Using MiSeq 16S rRNA sequencing, we identified several recognized (Alcanivorax, Marinobacter, Oleispira, Porticoccus, Thalassospira) and putative hydrocarbon degraders (Colwelliaceae, Vibrionaceae) tightly associated with the phytoplankton population. We combined fluorescence in situ hybridisation with flow-cytometry (FISH-Flow) to examine the association of Marinobacter with this natural eukaryotic phytoplankton population. About 1.5% of the phytoplankton population contained tightly associated Marinobacter. The remaining Marinobacter population were loosely associated with either eukaryotic phytoplankton cells or non-chlorophyll particulate material. This work is the first to show the presence of obligate, generalist and putative hydrocarbonoclastic bacteria associated with natural populations of eukaryotic phytoplankton directly from sea surface water samples. It also highlights the suitability of FISH-Flow for future studies to examine the spatial and temporal structure and dynamics of these and other algal-bacterial associations in natural seawater samples.

Acquired fluoroquinolone resistance genes in corneal isolates of Pseudomonas aeruginosa.

Fluoroquinolones are widely used as an empirical therapy for pseudomonal ocular infections. Based on increasing reports on acquired fluoroquinolone resistance genes in clinical isolates of Pseudomonas aeruginosa, we investigated 33 strains of P. aeruginosa isolated from the cornea of microbial keratitis patients in India and Australia between 1992 and 2018 to understand the prevalence of acquired fluoroquinolone resistance genes in ocular isolates and to assess whether the possession of those genes was associated with fluoroquinolone susceptibility. Fourteen out of 33 strains were resistant to at least one fluoroquinolone. We obtained the whole genome sequence of 33 isolates using Illumina MiSeq platform and investigated the prevalence of two fluoroquinolone resistance genes crpP and qnrVC1. To examine the associated mobile genetic elements of qnrVC1 positive strains, we obtained long read sequences using Oxford Nanopore MinION and performed hybrid assembly to combine long reads with Illumina short sequence reads. We further assessed mutations in quinolone resistance determining regions (QRDRs) and antibiotic susceptibilities to ciprofloxacin, levofloxacin and moxifloxacin to examine the association between resistance genes and phenotype. Twenty strains possessed crpP in genetic islands characterised by possession of integrative conjugative elements. The qnrVC1 gene was carried by four isolates on class I integrons and Tn3 transposons along with aminoglycoside and beta-lactam resistance genes. We did not observe any evidence of plasmids carrying fluoroquinolone resistance genes. Resistance to fluoroquinolones was observed in those strains which possessed crpP, qnrVC1 and that had QRDRs mutations. The presence of crpP on its own was not associated with increased resistance to fluoroquinolones.

Antibiotic Resistance Characteristics of Pseudomonas aeruginosa Isolated from Keratitis in Australia and India.

This study investigated genomic differences in Australian and Indian Pseudomonas aeruginosa isolates from keratitis (infection of the cornea). Overall, the Indian isolates were resistant to more antibiotics, with some of those isolates being multi-drug resistant. Acquired genes were related to resistance to fluoroquinolones, aminoglycosides, beta-lactams, macrolides, sulphonamides, and tetracycline and were more frequent in Indian (96%) than in Australian (35%) isolates (p = 0.02). Indian isolates had large numbers of gene variations (median 50,006, IQR = 26,967-50,600) compared to Australian isolates (median 26,317, IQR = 25,681-33,780). There were a larger number of mutations in the mutL and uvrD genes associated with the mismatch repair (MMR) system in Indian isolates, which may result in strains losing their efficacy for DNA repair. The number of gene variations were greater in isolates carrying MMR system genes or exoU. In the phylogenetic division, the number of core genes were similar in both groups, but Indian isolates had larger numbers of pan genes (median 6518, IQR = 6040-6935). Clones related to three different sequence types-ST308, ST316, and ST491-were found among Indian isolates. Only one clone, ST233, containing two strains was present in Australian isolates. The most striking differences between Australian and Indian isolates were carriage of exoU (that encodes a cytolytic phospholipase) in Indian isolates and exoS (that encodes for GTPase activator activity) in Australian isolates, large number of acquired resistance genes, greater changes to MMR genes, and a larger pan genome as well as increased overall genetic variation in the Indian isolates.

Exposure to Pb-halide perovskite nanoparticles can deliver bioavailable Pb but does not alter endogenous gut microbiota in zebrafish.

Lead-halide perovskite nanoparticles (NPs) are a new technology, and investigation of toxicity is of considerable importance due to the potential lead (Pb) release into the environment. The aim of the study was to investigate aqueous and dietary toxicity of Pb-halide perovskite NP and Pb in zebrafish Danio rerio. Perovskite NP toxicity was evaluated in zebrafish by mortality, gene expression, histopathology, and phylogenetic analysis of gut microbiota. Zebrafish larvae were exposed to five Pb-halide perovskite NPs in parallel with Pb(NO3)2 exposures, and zebrafish adults were exposed to the three perovskite NPs that caused the strongest effect and Pb(NO3)2. No median lethal concentration (LC50) was observed for zebrafish larvae exposed to up to 200 mg/L of perovskite NPs for 96 h. Mortality, metallothionein 2 (mt2) and δ-aminolevulinic acid dehydratase (ala-d) gene expression (24-h exposure) in zebrafish larvae after aqueous perovskite NPs exposures did not differ from total Pb concentration - response curves. The lack of differences in mortality and gene expression between perovskite NPs and soluble Pb after aqueous exposure suggest that toxicity from perovskite NPs can be attributed to bioavailable Pb rather than nano-specific effects. Induction of mt2 and reduction of ala-d expression levels in liver tissues showed Pb bioavailability after 2-d and 4-d dietary exposure to perovskite-spiked feeds. Changes in gut microbiota of adult zebrafish were detected after 14-d exposure to Pb-spiked food, but no changes were detected from perovskite-NP spiked food. The phylogenetic analysis identified different microbiome profiles of Pb-fed fish compared to perovskite-fed fish suggesting a different mechanism of toxicity. Exposure to Pb-halide perovskite NPs led to absorption of Pb likely from release of Pb ions rather than absorption of NPs. Pb-halide perovskite NPs can release bioavailable Pb and this needs to be considered during the development of this technology.

Chemical Dispersant Enhances Microbial Exopolymer (EPS) Production and Formation of Marine Oil/Dispersant Snow in Surface Waters of the Subarctic Northeast Atlantic.

A notable feature of the Deepwater Horizon oil spill was the unprecedented formation of marine oil snow (MOS) that was observed in large quantities floating on the sea surface and that subsequently sedimented to the seafloor. Whilst the physical and chemical processes involved in MOS formation remain unclear, some studies have shown that extracellular polymeric substances (EPS) play a role in this process. Here, we report that during exposure of subarctic northeast Atlantic seawater to a chemical dispersant, whether in the presence/absence of crude oil, the dispersant stimulates the production of significant quantities of EPS that we posit serves as a key building block in the formation of MOS. This response is likely conferred via de novo synthesis of EPS by natural communities of bacteria. We also describe the formation of marine dispersant snow (MDS) as a product of adding chemical dispersants to seawater. Differential staining confirmed that MDS, like MOS, is composed of glycoprotein, though MDS is more protein rich. Using barcoded-amplicon Illumina MiSeq sequencing, we analyzed, for the first time, the bacterial communities associated with MDS and report that their diversity is not significantly dissimilar to those associated with MOS aggregates. Our findings emphasize the need to conduct further work on the effects of dispersants when applied to oil spills at sea, particularly at different sites, and to determine how the product of this (i.e., MOS and MDS) affects the biodegradation of the oil.

Complete Genome Sequence of Thalassotalea euphylliae Strain H2.

A bacterial isolate of Thalassotalea euphylliae H2 was collected from the coral Montipora capitata. MinION long reads were employed for scaffolding and complemented with short-read MiSeq sequences to permit complete genome assembly. The genome is approximately 4.36 Mb long, with 3,669 protein-coding genes, 92 tRNAs, and 21 rRNAs.

Endoscopic Management of Iatrogenic Ureteral Injury: A Case Report and Review of the Literature.

Background: Iatrogenic ureteral injury represents an uncommon, but significant, complication of gynecologic surgery. Endoscopy has typically played little to no role in the treatment of these injuries, which are traditionally managed with re-exploration or delayed repair. Delayed repair with temporary urinary diversion exposes the patient to significant morbidity. We present a case in which iatrogenic ureteral injury is managed definitively with endoscopy alone. Case Presentation: We present a 32-year-old female who developed a delayed postpartum hemorrhage following cesarean section, necessitating emergent hysterectomy. Postoperatively, there was concern for right ureteral injury. A computed tomography (CT) urogram was obtained showing right-sided hydronephrosis, but no obvious ureteral injury. After developing right flank pain, the patient was taken to the operating room for further evaluation. On semirigid ureteroscopy, a suture was identified within the lumen of the ureter and incised with the holmium laser, effectively treating the obstruction. At a 10-week follow-up, a renal ultrasound showed no hydronephrosis. At 8 months, the patient reports she is doing well with no flank pain. Conclusion: We present, to the best of our knowledge, the first published report in the United States of an iatrogenic ureteral ligation managed effectively in an acute postoperative setting with endoscopic holmium laser release, without balloon dilation, sparing the patient from delayed surgical intervention and the potentially associated morbidity. It is our belief that an initial retrograde pyelogram followed by a ureteroscopic evaluation should be performed as this allows for proper characterization of the injury, and may allow one to attempt definitive endoscopic management.

Full-Genome Sequence of Thalassotalea euphylliae H1, Isolated from a Montipora capitata Coral Located in Hawai'i.

The isolate of Thalassotalea euphylliae H1 was collected from the surface of a Montipora capitata coral. The genome was assembled using long reads from a Nanopore MinION sequencer for scaffolding and complemented with short-read MiSeq sequences. The genome was approximately 4.77 Mb long with 4,020 protein-coding genes, 92 tRNAs, and 22 rRNAs.

The Microbial Community of a Terrestrial Anoxic Inter-Tidal Zone: A Model for Laboratory-Based Studies of Potentially Habitable Ancient Lacustrine Systems on Mars.

Evidence indicates that Gale crater on Mars harboured a fluvio-lacustrine environment that was subjected to physio-chemical variations such as changes in redox conditions and evaporation with salinity changes, over time. Microbial communities from terrestrial environmental analogues sites are important for studying such potential habitability environments on early Mars, especially in laboratory-based simulation experiments. Traditionally, such studies have predominantly focused on microorganisms from extreme terrestrial environments. These are applicable to a range of Martian environments; however, they lack relevance to the lacustrine systems. In this study, we characterise an anoxic inter-tidal zone as a terrestrial analogue for the Gale crater lake system according to its chemical and physical properties, and its microbiological community. The sub-surface inter-tidal environment of the River Dee estuary, United Kingdom (53°21'15.40″ N, 3°10'24.95″ W) was selected and compared with available data from Early Hesperian-time Gale crater, and temperature, redox, and pH were similar. Compared to subsurface 'groundwater'-type fluids invoked for the Gale subsurface, salinity was higher at the River Dee site, which are more comparable to increases in salinity that likely occurred as the Gale crater lake evolved. Similarities in clay abundance indicated similar access to, specifically, the bio-essential elements Mg, Fe and K. The River Dee microbial community consisted of taxa that were known to have members that could utilise chemolithoautotrophic and chemoorganoheterotrophic metabolism and such a mixed metabolic capability would potentially have been feasible on Mars. Microorganisms isolated from the site were able to grow under environment conditions that, based on mineralogical data, were similar to that of the Gale crater's aqueous environment at Yellowknife Bay. Thus, the results from this study suggest that the microbial community from an anoxic inter-tidal zone is a plausible terrestrial analogue for studying habitability of fluvio-lacustrine systems on early Mars, using laboratory-based simulation experiments.

Agglomeration of nano- and microplastic particles in seawater by autochthonous and de novo-produced sources of exopolymeric substances.

Microplastics (<5 mm) have often been studied under in-vitro conditions where plastics have been investigated in isolation. However, in the natural environment microplastics readily form agglomerates conferring the particles with properties different to their pristine counterparts. Here, we examined the interaction of exopolymers with polystyrene nanoplastics and microplastics. Formation of plastic agglomerates was examined using simulated sea surface conditions. Flow cytometry coupled with microscopy revealed that nano- and microplastic particle spheres form agglomerates in seawater with a mucilagenous material and an associated microbial community. To characterise this material, differential staining methods revealed it to be glycoprotein in composition. Exposing increasing concentrations of a marine bacterial glycoprotein EPS to nano- or microplastics revealed that these types of polymers contribute to the formation and abundance of plastic agglomerates. This work highlights the importance of EPS on the fate of plastic and future research should take this into account when evaluating the impact of plastics.

Patency and Incontinence Rates After Robotic Bladder Neck Reconstruction for Vesicourethral Anastomotic Stenosis and Recalcitrant Bladder Neck Contractures: The Trauma and Urologic Reconstructive Network of Surgeons Experience.

OBJECTIVE: To review a robotic approach to recalcitrant bladder neck obstruction and to assess success and incontinence rates. MATERIALS AND METHODS: Patients with a recalcitrant bladder neck contracture or vesicourethral anastomotic stenosis who underwent robotic bladder neck reconstruction (RBNR) were identified. We reviewed patient demographics, medical history, etiology, previous endoscopic management, cystoscopic and symptomatic outcomes, urinary continence, and complications. Stricture success was anatomic and functional based upon atraumatic passage of a 17 Fr flexible cystoscope or uroflowmetry rate >15 ml/s. Incontinence was defined as the use of >1 pad per day or procedures for incontinence. RESULTS: Between 2015 and 2017, 12 patients were identified who met study criteria and underwent RBNR. Etiology of obstruction was endoscopic prostate procedure in 7 and radical prostatectomy in 5. The mean operative time was 216 minutes (range 120-390 minutes), with a mean estimated blood loss of 85 cc (range 5-200 cc). Median length of stay was 1 day (range 1-5 days). Three of 12 patients had recurrence of obstruction for a 75% success rate. Additionally, 82% of patients without preoperative incontinence were continent with a median follow-up of 13.5 months (range 5-30 months). There was 1 Clavien IIIb complication of osteitis pubis and pubovesical fistula that required vesicopubic fistula repair with pubic bone debridement. CONCLUSION: RBNR is a viable surgical option with high patency rates and favorable continence outcomes. This is in contrast to perineal reconstruction, which has high incontinence rates. If future incontinence procedures are needed, outcomes may be improved given lack of previous perineal dissection.

Role of EPS, Dispersant and Nutrients on the Microbial Response and MOS Formation in the Subarctic Northeast Atlantic.

In this study we report the formation of marine oil snow (MOS), its associated microbial community, the factors influencing its formation, and the microbial response to crude oil in surface waters of the Faroe-Shetland Channel (FSC). The FSC is a subarctic region that is hydrodynamically complex located in the northeast Atlantic where oil extraction is currently occurring and where exploration is likely to expand into its deeper waters (>500 m). A major oil spill in this region may mirror the aftermath that ensued following the Deepwater Horizon (DWH) blowout in the Gulf of Mexico, where the massive influx of Macondo crude oil triggered the formation of copious quantities of rapidly sinking MOS and successional blooms of opportunistic oil-degrading bacteria. In laboratory experiments, we simulated environmental conditions in sea surface waters of the FSC using water collected from this site during the winter of 2015. We demonstrated that the presence of dispersant triggers the formation of MOS, and that nutrient amendments magnify this. Illumina MiSeq sequencing revealed the enrichment on MOS of associated oil-degrading (Cycloclasticus, Thalassolituus, Marinobacter) and EPS-producing (Halomonas, Pseudoalteromonas, Alteromonas) bacteria, and included major representation by Psychrobacter and Cobetia with putative oil-degrading/EPS-producing qualities. The formation of marine snow, in the absence of crude oil and dispersant, in seawater amended with nutrients alone indicated that the de novo synthesis of bacterial EPS is a key factor in MOS formation, and the glycoprotein composition of the MOS aggregates confirmed that its amorphous biopolymeric matrix was of microbial (likely bacterial) origin. The presence of dispersants and crude oil with/without nutrients resulted in distinct microbial responses marked by intermittent, and in some cases short-lived, blooms of opportunistic heterotrophs, principally obligate hydrocarbonoclastic (Alcanivorax, Cycloclasticus, Thalassolituus, Marinobacter) and EPS-producing (Halomonas, Alteromonas, Pseudoalteromonas) bacteria. Interestingly, members of the Vibrionales (principally the genus Vibrio) were strongly enriched by crude oil (with/without dispersant or nutrients), highlighting a putative importance for these organisms in crude oil biodegradation in the FSC. Our findings mirror those observed at DWH and hence underscore their broad relevance.