The emerging and increasing prevalence of bacterial antibiotic resistance is a significant public health challenge. To begin to tackle this problem, it will be critical to not only understand the origins of this resistance but also document environmental reservoirs of antibiotic resistance. In this study we investigated the possibility that both colony and field caught mosquitoes could harbor antibiotic resistant bacteria. Specifically, we characterized the antibiotic resistant bacterial populations from colony-reared Aedes aegypti larvae and adults and two field caught mosquito species Coquillettidia perturbans and Ochlerotatus canadensis . The cultured bacterial populations were dominated by isolates belonging to the class Gammaproteobacteria. Among the antibiotic resistant populations, we found bacteria resistant to carbenicillin, kanamycin, and tetracycline, including bacteria resistant to a cocktail of all three antibiotics in combination. The antibiotic resistant bacteria were numerically rare, at most 5% of total cell counts. Isolates were characterized by 16S rRNA gene sequencing, and clustering into Operational Taxonomic Units (OTUs; 99% sequence identity). 27 antibiotic resistant OTUs were identified, although members of an OTU did not always share the same resistance profile. This suggests the clustering was either not sensitive enough to distinguish different bacteria taxa or different antibiotic resistant sub-populations exist within an OTU. Finally, the antibiotic selection opened up a niche to culture mosquito-associated fungi, and 10 fungal OTUs (28S rRNA gene sequencing) were identified. Two fungal OTUs both classified to the class Microbotryomycetes were commonly identified in the field-caught mosquitoes. Thus, in this study we demonstrate that antibiotic resistant bacteria and certain fungi are common and conserved mosquito microbiome members. These observations highlight the potential of invertebrates to serve as vehicles for the spread of antibiotic resistance throughout the environment.

47The emerging and increasing prevalence of bacterial antibiotic resistance is a 48 significant public health challenge. To begin to tackle this problem, it will be critical to 49 not only understand the origins of this resistance but also document environmental 50 reservoirs of antibiotic resistance. In this study we investigated the possibility that both 51 colony and field caught mosquitoes could harbor antibiotic resistant bacteria.52 Specifically, we characterized the antibiotic resistant bacterial populations from colony-53 reared Aedes aegypti larvae and adults and two field caught mosquito species 54 Coquillettidia perturbans and Ochlerotatus canadensis. The cultured bacterial 55 populations were dominated by isolates belonging to the class Gammaproteobacteria. 56 Among the antibiotic resistant populations, we found bacteria resistant to carbenicillin, 57 kanamycin, and tetracycline, including bacteria resistant to a cocktail of all three 58 antibiotics in combination. The antibiotic resistant bacteria were numerically rare, at most 59 5% of total cell counts. Isolates were characterized by 16S rRNA gene sequencing, and 60 clustering into Operational Taxonomic Units (OTUs; 99% sequence identity). 27 61 antibiotic resistant OTUs were identified, although members of an OTU did not always 62 share the same resistance profile. This suggests the clustering was either not sensitive 63 enough to distinguish different bacteria taxa or different antibiotic resistant sub-64 populations exist within an OTU. Finally, the antibiotic selection opened up a niche to 65 culture mosquito-associated fungi, and 10 fungal OTUs (28S rRNA gene sequencing) 66 were identified. Two fungal OTUs both classified to the class Microbotryomycetes were 67 commonly identified in the field-caught mosquitoes. Thus, in this study we demonstrate68 that antibiotic resistant bacteria and certain fungi are common and conserved mosquito 3 69 microbiome members. These observations highlight the potential of invertebrates to serve 70 as vehicles for the spread of antibiotic resistance throughout the environment.

250 words) 1 Development of sudden vegetation dieback (SVD), a phenomenon that causes 2 the rapid mortality of salt marsh plants, specifically Spartina alterniflora, has 3 affected large-scale alterations in Atlantic coastal systems, through the often-4 complete removal of vegetation. In this study, two wetlands that differ in the time 5 since development of SVD were compared in order to study biogeographic and 6 temporal patterns that structure coastal wetland microbial communities and their 7 response to disturbance. 8Biogeographic and edaphic factors that distinguished the two wetlands, such 9 as differing salinity, water content, and soil carbon and nitrogen between the sites 10 were more strongly associated with sediment microbial community structure than 11 either sampling date or SVD development. In fact, no OTUs differed in abundance 12 due to the season samples were collected, or vegetation loss due to SVD. This is not 13 to say that SVD did not alter the composition of the microbial communities. The 14 taxonomic composition of sediment communities in SVD-affected sediments was 15 more heterogeneous between samples and a small number of OTUs were enriched 16 in the vegetated sediments. Yet, these data suggest that coastal wetland sediment 17 communities are predominantly shaped by environmental conditions and are 18 generally resilient to temporal cycles or ecosystem disturbances. 19 20 Importance (150 words) 21One of the challenges of microbial ecology is predicting how microbial 22 communities will respond to ecosystem change. Yet, few studies have addressed whether 23 3 microbial responses to disturbance are consistent over space or time. In this study we 24 employ SVD as a natural vegetation removal experiment and compare the sediment 25 microbial communities between two geographically separated wetlands (ca 125 km). In 26 this manner, we uncover a hierarchical structuring of the microbial communities, being 27 predominantly governed by biogeography, with lesser effects due to disturbance, or 28 temporal dynamics. 29In the present study, we compared sediment microbial communities between two 71 salt marshes both experiencing current outbreaks of SVD. However, the time since SVD 72 development differed between the two sites (5 versus. 10 years). To examine the relative 73 role of vegetation, we examined sediment microbial communities in summer (July) 74 during peak plant activity, and in fall (October) when salt marsh plants begin senescence. 75 field sampling. This work was supported by the USDA National Institute of Food and 388 Agriculture, Hatch project 1006211. 389 390 391 392 References 393 1. Mcleod E, Chmura GL, Bouillon S, Salm R, Björk M, Duarte CM, Lovelock CE, 394 Schlesinger WH, Silliman BR. 2011. A blueprint for blue carbon: toward an 395 improved understanding of the role of vegetated coastal habitats in sequestering 396 CO 2. Front Ecol Environ 9:552-560. 397 7. Armitage A, Fourqurean J. 2016. Carbon storage in seagrass soils: long-term 409 nutrient history exceeds the effects of near-...