Nantucket Research Articles

Minor Hosts Have a Major Impact on the Enzootic Transmission of Borrelia burgdorferi.

In the northeast United States, subadult deer ticks feeding on white-footed mice are thought to drive the force of transmission of Borrelia burgdorferi (B. burgdorferi), the agent of Lyme disease. However, control measures targeting mice have produced inconsistent results, suggesting that other animals are significant contributors to enzootic transmission. Such contributions have previously been difficult to quantify. We used a retrotransposon-based host blood meal assay to measure the relative contribution of hosts to enzootic B. burgdorferi transmission at two insular sites in Massachusetts. Over 6 years, we identified mice and deer as the most common larval hosts at our Nantucket Island site. Infected nymphal ticks were derived mainly from mice (35%) and shrews (31%), despite shrews having fed only 12% of larvae. Deer were identified in 19% of the infected nymphs, despite their known reservoir incompetence. Shrews were consistently the most important host in our Martha's Vineyard site and were identified as the source of 41% of nymphs overall and 39% of the infected nymphs. Sciurids were variable contributors, feeding from 4% to 42% of the larval ticks each year, and contributed no infected nymphs in 2020 and as many as 83% in 2023. We conclude that host contributions to feeding larval ticks change over time and within sites and that shrews may be more influential than mice at some sites. Shrews, sciurids, and even deer may contribute to B. burgdorferi maintenance. Hosts that apparently feed a minor proportion of ticks can have a major impact on the force of B. burgdorferi transmission.

From Shelfbreak to Shoreline: Coastal Sea Level and Local Ocean Dynamics in the Northwest Atlantic

AbstractSea‐level change threatens the U.S. East Coast. Thus, it is important to understand the underlying causes, including ocean dynamics. Most past studies emphasized links between coastal sea level and local atmospheric variability or large‐scale circulation and climate, but possible relationships with local ocean currents over the shelf and slope remain largely unexplored. Here we use 7 years of in situ velocity and sea‐level data to quantify the relationship between northeastern U.S. coastal sea level and variable Shelfbreak Jet transport south of Nantucket Island. At timescales of 1–15 days, southern New England coastal sea level and transport vary in anti‐phase, with magnitude‐squared coherences of ∼0.5 and admittance amplitudes of ∼0.3 m Sv−1. These results are consistent with a dominant geostrophic balance between along‐shelf transport and coastal sea level, corroborating a hypothesis made decades ago that was not tested due to the lack of transport data.

What Forcing Mechanisms Affect the Interannual Sea Level Co‐Variability Between the Northeast and Southeast Coasts of the United States?

AbstractInterannual sea‐level variations between the United States (U.S.) Northeast and Southeast Coasts separated by Cape Hatteras are significantly less correlated than those within their respective sectors, but the cause is poorly understood. Here we investigate atmospheric forcing mechanisms that affect the interannual sea‐level co‐variability between these two sectors using an adjoint reconstruction and decomposition approach in the framework of Estimating the Circulation and Climate of the Ocean (ECCO) ocean state estimate. We compare modeled and observed sea‐level changes at representative locations in each sector: Nantucket Island, Massachusetts for the Northeast and Charleston, South Carolina for the Southeast. The adjoint reconstruction and decomposition approach used in this work allows for identification and quantification of the causal mechanisms responsible for observed coastal sea‐level variability. Coherent sea‐level variations in Nantucket and Charleston arise from nearshore wind stress anomalies north of Cape Hatteras and buoyancy forcing, especially from the subpolar North Atlantic, while offshore wind stress anomalies, in contrast, reduce co‐variability. Offshore wind stress contributes much more to interannual sea‐level variation at Charleston than at Nantucket, causing incoherent sea level variations between the two locations. Buoyancy forcing anomalies south of Charleston, including over the Florida shelf, the Gulf of Mexico, and the Caribbean Sea, also reduce co‐variability because they induce sea‐level responses at Charleston but not Nantucket. However, the relative impact of buoyancy forcing on interannual sea‐level co‐variability between the two sectors is much smaller than that of offshore wind stress.

Seasonal roost characteristics and fall behavior of coastal populations of Northern Myotis (Myotis septentrionalis)

Abstract Temperate bats exhibit seasonal and sex differences in resource selection and activity patterns that are influenced by ambient conditions. During fall, individuals face energetic trade-offs as they make choices relating to migration, mating, and hibernation that may diverge for populations throughout their range. However, research has largely focused on the summer maternity and winter hibernation seasons, whereas the prehibernation period remains comparatively understudied. Northern Myotis (Myotis septentrionalis) have experienced precipitous population declines from white-nose syndrome (WNS), leading to their protected status in the United States and Canada. Therefore, understanding their ecology throughout the year is paramount to inform conservation. We compared seasonal roosts and documented fall behaviors between study sites and sexes on 3 islands: Long Island (New York), Martha’s Vineyard, and Nantucket Island (Massachusetts). Between 2017 and 2020, we radio-tracked 54 individuals to analyze activity patterns and characterize fall roosts to compare with previously known summer roosts. Summer tree roosts were of smaller diameter, later stages of decay, and lower canopy closure than those used in fall. Both sexes selected trees of similar diameter and decay stage during fall. Anthropogenic roost use was documented in both seasons but use of anthropogenic structures was greater during fall and increased as the season progressed. Bats made short inter-roost movements with males traveling greater distances than females on average. Activity occurred until late November, with males exhibiting a longer active period than females. We tracked 23% of tagged bats to local hibernacula in subterranean anthropogenic structures, the majority of which were crawlspaces underneath houses. Use of anthropogenic structures for roosts and hibernacula may facilitate survival of this species in coastal regions despite the presence of WNS infections. Timing of restrictions on forest management activities for bat conservation may be mismatched based on prehibernation activity observed in these coastal populations, and the conservation of habitat surrounding anthropogenic roosts or hibernacula may be warranted if the structures themselves cannot be protected.

Eelgrass (Zostera marina L.) populations are threatened by high sea-surface temperatures and impaired waters on Nantucket Island, USA

Eelgrass (Zostera marina L.) is a key foundation species that provides multiple ecosystem services to shallow coastal and estuarine systems in the Northern Hemisphere. It is estimated that, over the last century, up to 50 % of all Z. marina habitat has been lost along the east coast of the USA due to factors including light reduction, eutrophication, and physical disturbance. Warming sea surface temperatures are also believed to be exacerbating losses and the future of this ecosystem is unclear. Here, we assess Z. marina meadows on Nantucket, an island system located 50 km off-shore of Massachusetts, by using common indicators of seagrass plant health and environmental quality. Our results show that Z. marina meadows on Nantucket Island are thermally stressed and light-limited during parts of their peak growing season. This suggests that sea-surface temperatures are a pivotal factor, along with cultural eutrophication, in observed large-scale losses of Z. marina and that further degradation could be expected in the future as the climate continues to warm. Methods from this study may be used by managers as a guide to assess seagrass ecosystem status in degrading systems.

Introgression and persistence of cultivar alleles in wild carrot (Daucus carota) populations in the United States.

Cultivated species and their wild relatives often hybridize in the wild, and the hybrids can survive and reproduce in some environments. However, it is unclear whether cultivar alleles are permanently incorporated into the wild genomes or whether they are purged by natural selection. This question is key to accurately assessing the risk of escape and spread of cultivar genes into wild populations. We used genomic data and population genomic methods to study hybridization and introgression between cultivated and wild carrot (Daucus carota) in the United States. We used single nucleotide polymorphisms (SNPs) obtained via genotyping by sequencing for 450 wild individuals from 29 wild georeferenced populations in seven states and 144 cultivars from the United States, Europe, and Asia. Cultivated and wild carrot formed two genetically differentiated groups, and evidence of crop-wild admixture was detected in several but not all wild carrot populations in the United States. Two regions were identified where cultivar alleles were present in wild carrots: California and Nantucket Island (Massachusetts). Surprisingly, there was no evidence of introgression in some populations with a long-known history of sympatry with the crop, suggesting that post-hybridization barriers might prevent introgression in some areas. Our results provide support for the introgression and long-term persistence of cultivar alleles in wild carrots populations. We thus anticipate that the release of genetically engineered (GE) cultivars would lead to the introduction and spread of GE alleles in wild carrot populations.

Tick Densities and Infection Prevalence on Coastal Islands in Massachusetts, USA: Establishing a Baseline.

Tick-borne diseases and a tick-induced red meat allergy have become increasingly common in the northeastern USA and elsewhere. At the scale of local communities, few studies have documented tick densities or infection levels to characterize current conditions and provide a baseline for further monitoring. Using the town of Nantucket, MA, as a case study, we recorded tick densities by drag sampling along hiking trails in nature preserves on two islands. Nymphal blacklegged ticks (Ixodes scapularis Say) were most abundant at shadier sites and least common in grasslands and scrub oak thickets (Quercus ilicifolia). Lone star ticks (Amblyomma americanum L.) were common on Tuckernuck Island and rare on Nantucket Island, while both tick species were more numerous in 2021 compared to 2020 and 2022. We tested for pathogens in blacklegged nymphs at five sites over two years. In 2020 and 2021, infection levels among the four Nantucket Island sites averaged 10% vs. 19% for Borrelia burgdorferi, 11% vs. 15% for Babesia microti, and 17% (both years) for Anaplasma phagocytophilum, while corresponding levels were significantly greater on Tuckernuck in 2021. Our site-specific, quantitative approach represents a practical example of how potential exposure to tick-borne diseases can be monitored on a local scale.

Euphorbia ipecacuanhae on Nantucket: A Historical State Record Comes to Light

Euphorbia ipecacuanhae L. is an herbaceous perennial of disturbed, sandy habitats of the Atlantic coastal plain, ranging from Georgia to southern New England. Most references list Hartford County, Connecticut, as the northernmost station and the only New England record for the species. However, we recently encountered a putative record from Nantucket, Massachusetts, U.S.A., and investigated its validity. Using a combination of physical inspection of the specimen and biographical details of the collector, Lorin Low Dame, we conclude that E. ipecacuanhae was collected from the island of Nantucket in the late 19th century, expanding the known natural range for the species. We also discuss habitat and landscape-scale ecological processes that would have supported the species at that time and prospects for its rediscovery in New England.

Nantucket's Neglected Herbivores II: Diptera

Records of Diptera and their hymenopteran parasitoids are reported from a ten-year study of herbivorous insects of Nantucket Island, Massachusetts, USA, with a focus on searching for galls, leaf mines, and other characteristic feeding evidence on host plants. Our field observations and reared specimens are supplemented with herbarium records and Johnson's (1930) list of the insect fauna of Nantucket. Compared with Johnson's list of nine species of Agromyzidae, we identified 53 along with 15 others determined only to genus or higher taxa (a few of the latter could conceivably be conspecific with the former or with one another). We found 37 named species of Cecidomyiidae (including eight of the nine on Johnson's list), as well as 26 others that are undescribed or are currently unidentifiable for other reasons (a few of which could conceivably be conspecific with one of the identified species, or represent galls not actually caused by midges). A few rearings and collections of Anthomyiidae, Chloropidae, Ephydridae, Phoridae, Sphaeroceridae, and Tephritidae are reported, adding another seven species and two genera to Johnson's list. Cerodontha (Dizygomyza) edithae Eiseman and Lonsdale (Agromyzidae), an as yet undescribed species of Ophiomyia Braschnikov (Agromyzidae), Megaselia nantucketensis Eiseman and Hartop (Phoridae), and the cecidomyiid parasitoids Platygaster tephrosiae Buhl and Eiseman and P. vitisiellae Buhl and Eiseman (Hymenoptera: Platygastridae) are known only from specimens reared as part of this study, which also produced paratypes of Liriomyza pistilla Lonsdale (Agromyzidae). Noteworthy cecidomyiid records include the first known specimens of an undescribed Asphondylia Loew on Solidago sempervirens L. (Asteraceae), galls of an undetermined lasiopterid species on Tephrosia virginiana (L.) Pers. (Fabaceae) that have only been found on Nantucket, and previously unreported galls on Gaylussacia baccata (Wangenh.) K. Koch (Ericaceae), Ionactis linariifolia (L.) Greene (Asteraceae) (Dasineura Rondani sp.), Quercus prinoides Willd. (Fagaceae), Salix purpurea L. (Salicaceae), and Solidago latissimifolia Mill. (Asteraceae) (Asphondylia sp., Rhopalomyia Rübsaamen sp.).

Testing for Hybridization between Centaurea stoebe and Centaurea jacea (Asteraceae) in the Isolated Island Setting of Nantucket, Massachusetts, U.S.A.

Spotted knapweed (Centaurea stoebe) and brown knapweed (Centaurea jacea) are members of the Asteraceae and natives of Eurasia. Centaurea stoebe is a major invasive species in North America, dominating large stretches of grassland. It also is known to form hybrids in North America with closely related naturalized Centaurea spp., including C. jacea. Both species were introduced on Nantucket Island, a coastal island 44 km south of Cape Cod, Massachusetts, and morphologically unusual, possible hybrid populations have been reported. The aim of this study was to test for hybridization between these weeds in an isolated setting. Chloroplast marker sequences revealed that all the hybrid-like plants shared the same haplotype with C. jacea populations. The analysis of nuclear markers with microsatellite markers showed surprisingly little intra- and inter-specific gene flow between populations and no evidence of hybridization between C. stoebe and C. jacea. Two populations with hybrid-like morphology are most likely environmental plastic morphs of C. jacea.

A Warm and A Cold Spot in Cape Cod Waters Amid the Recent New England Shelf Warming

Despite the widely recognized warming of the New England Continental Shelf (NES), climate patterns of the shelf’s economically and ecologically important coastal environments remain less examined. Here we use a satellite sea-surface temperature (SST) analysis gridded on 0.05°C spatial resolution to show, for the first time, the existence of a warm and a cold spot in the environs of Cape Cod, Massachusetts amid the NES warming of the past 15 years. The warm spot refers to an increasing warming trend in shallow waters of Nantucket Sound sheltered by the islands of Martha’s Vineyard and Nantucket. The summer SST maxima have increased by 3.1±1.0°C (p<0.1), about three times faster than the warming elsewhere on the NES, and the summer season has lengthened by 20 ± 7 days (p<0.1). The cold spot refers to an increasing cooling trend over Nantucket Shoals, an area of shallow sandy shelf that extends south and southeast from Nantucket Island and also known for strong tidal mixing. The strong cooling trend during June–August reduced the SST maxima by -2.5±1.2°C (p<0.1) and shortened the warm season by -32 ± 11 days (p<0.1). Away from the Cape Cod waters, the broad warming on the shelf is attributable to a forward shifted annual cycle. The shift is most significant in August–November, during which the summer temperatures lingered longer into the fall, producing a pronounced warming and delaying the onset of the fall season by 13 ± 6 days (p<0.1). The three different patterns of SST phenology trends displayed by the respective warm spot, the cold spot, and the broad shelf highlight the highly dynamically diverse responses of coastal waters under climate warming. Finally, the study showed that spatial resolution of SST datasets affects the characterization of the spatial heterogeneity in the nearshore SSTs. The widely used Optimum Interpolation SST (OISST) on 0.25°C resolution was examined. Although the two SST datasets agree well with the measurements from the moored buoys at four locations, OISST does not have the cold spot and shows a higher rate of warming on the shelf.

Local and Remote Forcing of Interannual Sea-Level Variability at Nantucket Island.

The relative contributions of local and remote wind stress and air‐sea buoyancy forcing to sea‐level variations along the East Coast of the United States are not well quantified, hindering the understanding of sea‐level predictability there. Here, we use an adjoint sensitivity analysis together with an Estimating the Circulation and Climate of the Ocean (ECCO) ocean state estimate to establish the causality of interannual variations in Nantucket dynamic sea level. Wind forcing explains 67% of the Nantucket interannual sea‐level variance, while wind and buoyancy forcing together explain 97% of the variance. Wind stress contribution is near‐local, primarily from the New England shelf northeast of Nantucket. We disprove a previous hypothesis about Labrador Sea wind stress being an important driver of Nantucket sea‐level variations. Buoyancy forcing, as important as wind stress in some years, includes local contributions as well as remote contributions from the subpolar North Atlantic that influence Nantucket sea level a few years later. Our rigorous adjoint‐based analysis corroborates previous correlation‐based studies indicating that sea‐level variations in the subpolar gyre and along the United States northeast coast can both be influenced by subpolar buoyancy forcing. Forward perturbation experiments further indicate remote buoyancy forcing affects Nantucket sea level mostly through slow advective processes, although coastally trapped waves can cause rapid Nantucket sea level response within a few weeks.

Class, climate change, and closed systems: inverted quarantine on Nantucket Island

ABSTRACT Environmental sociologists have debated the role of individual versus societal responses to climate change impacts and threats. Some are critical of all individual consumption-driven private responses; others see some value in conscious consumption. One characterization of private threat response is ‘inverted quarantine’: attempting to isolate an individual from a ‘sick’ world by purchasing safe products or spaces. Inverted quarantine scholars theorize this can have unintended consequences such as harm displacement onto the unprotected and redirection of resources toward privilege. Little work, however, has empirically documented the causal relationship between inverted quarantines and unintended consequences, which are typically spatially and temporally distant. This multi-method ethnography of Nantucket Island fills that gap by leveraging characteristics of ‘islandness,’ enabling observation of sequential processes of inverted quarantine, consequences, and responses. The study confirms that harm displacement and resource redirection occur. It also finds an additional, insidious consequence of inverted quarantines: a double bind impeding effective public solutions. Public solutions threaten the private-threat-response industry and therefore the livelihoods of laborers producing inverted quarantines. While creating the conditions for its own eventual failure, inverted quarantines may also guarantee their continued manufacture at the expense of public solutions, by monopolizing the means of economic and social reproduction.

Infestation of wild bay scallops Argopecten irradians on Nantucket Island by the shell-boring polychaete Polydora neocaeca.

Shell-boring polychaete worms can severely impact shellfish aquaculture by reducing growth rates and compromising tissue quality of their molluscan hosts. In this study we report the first known instance of shell-infestation of commercially important scallops on Nantucket Island by the cryptogenic polydorid Polydora neocaeca. Additional analyses indicate a high level of genetic connectivity between worms from Nantucket Island and the US mainland, forming a distinct haploclade which is genetically isolated from populations from South Africa and Japan. While transportation of infected seed could have introduced the worm to Nantucket, limited sampling and the paucity of sequence data available makes it impossible to definitely determine its origins.

Semicentennial of Human Babesiosis, Nantucket Island.

Fifty years ago, the index case of human babesiosis due to Babesia microti was diagnosed in a summer resident of Nantucket Island. Human babesiosis, once called “Nantucket fever” due to its seeming restriction to Nantucket and the terminal moraine islands of southern New England, has emerged across the northeastern United States to commonly infect people wherever Lyme disease is endemic. We review the history of babesiosis on Nantucket, analyze its epidemiology and ecology there, provide summaries of the first case histories, and comment on its future public health burden.

The detection of airborne anatoxin-a (ATX) on glass fiber filters during a harmful algal bloom

Sutherland JW, Turcotte RJ, Molden E, Moriarty V, Kelly M, Aubel M, Foss A. 2021. The detection of airborne anatoxin-a (ATX) on glass fiber filters during a harmful algal bloom. Lake Reserv Manage. 37:113–119. Anatoxin-a (ATX) is a neurotoxic alkaloid produced by certain cyanobacteria genera that can occur during harmful algal blooms (HABs). This study is the first to report airborne ATX collected outside an aquatic ecosystem. ATX was captured on glass fiber filters using a field-deployed air sampler during an active 2019 HAB at Capaum Pond on Nantucket Island, Massachusetts (USA). These findings indicate that emission of ATX molecules, or cyanobacteria containing ATX, during HABs presents a potential human health exposure not previously examined.

Changes to spotted turtle (Clemmys guttata) habitat selection in response to a salt marsh restoration

Development of coastal New England has led to the replacement of up to 37% of salt marshes with degraded freshwater wetlands, primarily through tidal restrictions. Removing these restrictions to restore salt marsh ecology would improve water quality, increase flood and storm protection, nutrient filtration, erosion control, and carbon sequestration. However, such restorations replace functional freshwater wetlands and could potentially impact freshwater species. Freshwater-dependent wildlife species such as the spotted turtle (Clemmys guttata), may be especially vulnerable to rapid changes in habitat resulting from tidal reintroduction due to their high site fidelity and limited ability to disperse quickly. Conservation of genetically and physically isolated spotted turtle populations as well as the restoration of salt marshes to mitigate climate change impacts are both high priorities on Nantucket Island. These two priorities conflicted in a project to restore tidal hydrology to an impounded freshwater marsh known to host a robust spotted turtle population. We evaluated changes to spotted turtle home range size and location and habitat use in response to salt marsh restoration over eight years. Home range size did not change but the location of home ranges shifted into bordering wetlands landward of the tidal salt water influence. Spotted turtles selected remaining freshwater marshes and shrub swamps while avoiding developed land and areas of establishing salt marsh within areas that had previously been high quality habitat. This study suggests prioritizing conservation of wetlands adjacent to planned salt marsh restoration to provide habitat for freshwater species to migrate.

15396 Factors affecting patient preferences between teledermatology and traditional face-to-face dermatology encounters

Teledermatology has been shown to be cost-effective, improve access to care, and decrease wait times for dermatology consultation. However, few studies have investigated patient preferences between teledermatology and face-to-face consultation. In addition, existing studies have demonstrated mixed results, suggesting a preference for face-to-face encounters. We took advantage of a unique circumstance, that patients on the Island of Nantucket, over a 5-year period have seen one dermatologist multiple times both in person and by real-time teledermatology.

A holistic approach to evaluating dune cores

As population density increases in coastal counties, shoreline stabilization efforts continue to gain momentum to protect infrastructure. Although protection techniques vary from ‘soft’ to ‘hard’ engineering, this paper focuses on a ‘hybrid’ technique utilizing geotubes as artificial dune cores. Previous literature presents conflicting results on the efficacy and potential impacts of dune cores on a beach-dune system. Here we evaluate and quantify the geomorphic impacts following dune core installation and investigate their economic feasibility. This was completed by comparing five case studies: Sea Isle City, NJ; Bolivar Peninsula, TX; Grand Isle, LA; Santa Rosa Beach, FL; and Nantucket Island, MA. An economic assessment was completed to compare dune core installation costs and repairs to alternative shoreline hardening methods. LiDAR data were used to compare dune slope, beach width, and beach volume between digital transects adjacent to and in front of the dune core installations. Digital elevation models (DEMs) were generated to provide a holistic view of geomorphic change and to assess whether erosion occurred landward of the dune core. Results indicate that dune cores are an economically feasible option compared to alternative methods. Limitations include UV exposure, wave influence, and heavy winds. Morphologically, beach width was 29.1% wider in adjacent transects and dune slope was 39.1% steeper in front of the dune core. Beach volume was lower by an overall average of 23.4%. The findings from this study suggest that dune cores are a ‘hard’ or ‘grey’ protection method.

Mercury Levels in Freshwater Fish: Estimating Concentration with Fish Length to Determine Exposures Through Fish Consumption.

Methylmercury (MeHg) is a neurotoxic pollutant that bioaccumulates and biomagnifies in aquatic food webs, impacting the health of piscivorous wildlife and human consumers of predatory fish. While fish mercury levels have been correlated with various biotic and abiotic factors, many studies only measure adults to characterize the health of locally fished populations, omitting information about how local fish bioaccumulate mercury relative to their growth. In this study, we sought to establish length: total mercury (THg) concentration relationships in juvenile and adult fish of four genera (sunfish, yellow perch, white perch, and killifish) across six freshwater pond systems of Nantucket Island to determine safe consumption sizes across species and environmental conditions. A wide length range (2-21cm) was utilized to develop linear regression models of ln-THg versus fish length. In most cases, different genera within the same pond indicated similar slopes, supporting that all four genera share comparable features of feeding and growth. Comparing individual species across ponds, differences in ln-THg versus fish length were attributable to known environmental Hg-modulators including surface water MeHg levels, pH, and watershed area. Referencing human health and wildlife criteria, our results confirm that numerous Nantucket freshwater ecosystems contain elevated fish THg levels, which could impact the health of not only piscivorous wildlife in all measured ponds but also recreational fishers in at least two measured systems. Future studies should measure THg levels across juvenile and adult fish to detect potential differences in the slope of THg concentration across fish length relevant for local consumption advice.