England Seamounts Research Articles

Slow Down of the Gulf Stream during 1993\u20132016

The Gulf Stream, the main heat-carrier from low to high latitudes in the North Atlantic Ocean, influences the climate and weather in the northern hemisphere. In this study we determine and analyze the position, speed, and width of the Gulf Stream (GS) from 80°W–50°W using satellite altimeter sea surface height (SSH) measurements to examine the possible link between changes in the strength of the GS and coastal sea levels along the U.S. East Coast. During our 24-year study period (1993–2016), the GS experienced a southward shift east of 65°W after passing the New England Seamount chain. This southward shift was accompanied by a weakening of the GS, associated with an increase in SSH to the north of the GS. West of 70°W, however, we found no statistically significant trends in the GS properties, consistent with results based on in situ measurements. This lack of a trend to the west fails to support a direct link between a long-term slowdown of the GS west of 70°W and sea level rise acceleration along the U.S. East Coast, though a slowdown of the GS east of 65°W may contribute to sea level rise. It is also possible that heat carried to the region by the GS may be responsible for these observed sea level changes.

Sonar and LiDAR investigation of lineaments offshore between central New England and the New England seamounts, USA

High-resolution multibeam echosounder (MBES) and light detection and ranging (LiDAR) data, combined with regional gravity and aeromagnetic anomaly maps of the western Gulf of Maine, reveal numerous lineaments between central New England and the New England seamounts. Most of these lineaments crosscut the NE-SWtrending accreted terranes, suggesting that they may be surface expressions of deep basement-rooted faults that have fractured upward through the overlying accreted terranes or may have formed by the upward push of magmas produced by the New England hotspot. The 1755 Cape Ann earthquake may have occurred on a fault associated with one of these lineaments. The MBES data also reveal a NW-SE-oriented scarp just offshore from Biddeford Pool, Maine (Biddeford Pool scarp), a 60-km-long, 20-km-wide Isles of Shoals lineament zone just offshore from southeastern New Hampshire, a 50-m-long zone of mostly low-lying, WNW-ESE-trending, submerged ridge-like features and scarps east of Boston, Massachusetts, and a ~180-km-long, WNW-ESE-trending Olympus lineament zone that traverses the continental margin south of Georges Bank. Three submarine canyons are sinistrally offset ~1–1.2 km along the Thresher canyon lineament of the Olympus lineament zone.

New data of Tetractinellida (Porifera) in Aviles Canyon system and Le Danois Bank (Cantabrian Sea). Results of the SponGES Project

New data of Tetractinellida (Porifera) in Aviles Canyon system and Le Danois Bank (Cantabrian Sea). Results of the SponGES Project

Instability-Driven Benthic Storms below the Separated Gulf Stream and the North Atlantic Current in a High-Resolution Ocean Model

AbstractBenthic storms are important for both the energy budget of the ocean and for sediment resuspension and transport. Using 30 years of output from a high-resolution model of the North Atlantic, it is found that most of the benthic storms in the model occur near the western boundary in association with the Gulf Stream and the North Atlantic Current, in regions that are generally collocated with the peak near-bottom eddy kinetic energy. A common feature is meander troughs in the near-surface jets that are accompanied by deep low pressure anomalies spinning up deep cyclones with near-bottom velocities of up to more than 0.5 m s−1. A case study of one of these events shows the importance of both baroclinic and barotropic instability of the jet, with energy being extracted from the jet in the upstream part of the meander trough and partly returned to the jet in the downstream part of the meander trough. This motivates examining the 30-yr time mean of the energy transfer from the (annual mean) background flow into the eddy kinetic energy. This quantity is shown to be collocated well with the region in which benthic storms and large increases in deep cyclonic relative vorticity occur most frequently, suggesting an important role for mixed barotropic–baroclinic instability-driven cyclogenesis in generating benthic storms throughout the model simulation. Regions of the largest energy transfer and most frequent benthic storms are found to be the Gulf Stream west of the New England Seamounts and the North Atlantic Current near Flemish Cap.

Ring-shaped morphological features and interpreted small seamounts between southern Quebec (Canada) and the New England seamounts (USA) and their possible association with the New England hotspot track

Enhancements of recently available high-resolution multibeam echosounder data from the western Gulf of Maine and Atlantic continental margin and light detection and ranging (LiDAR) and digital elevation model data from southeastern Quebec (Canada) and the northeastern United States have revealed numerous ring-shaped morphological features and interpreted small seamounts between the Monteregian Hills igneous province and the New England seamounts. The morphological features onshore are mainly ring-shaped depressions, several of which surround mapped igneous intrusions in the Monteregian Hills igneous province and White Mountain magma series. Most of the rings offshore are also depressions, although a few rings are curved ridges above the seafloor. The largest ring in the western Gulf of Maine is the 30-km-diameter Tillies ring that lies 20 km east of Cape Ann, MA. Several small (<3 km in diameter) round, flat-topped submerged hills that we interpret to be volcanic necks are also present beneath the western Gulf of Maine. The rings between Cape Cod and the continental slope are more subtle because of thicker sediments and poorer spatial resolution of the sonar data in this area. The southernmost ring-shaped features are located on the continental slope and upper continental rise and coincide with the northwestern end of the New England seamount chain. The concentration of these features between the Monteregian Hills igneous province and the New England seamounts suggests that they are igneous features that may be associated with the New England hotspot track.

First records of Geodia demosponges from the New England seamounts, an opportunity to test the use of DNA mini-barcodes on museum specimens

We report the first records of the sponge genus Geodia (Demospongiae, Tetractinellida, Geodiidae) from the New England Seamounts and Muir Seamount, at lower bathyal depths. Nine specimens collected between 2000 and 2005 belong to two boreal species (Geodia macandrewii and Geodia barretti) and a temperate species (Geodia megastrella). These records extend the distributions of these deep-sea amphi-Atlantic species to the west. Most of these specimens were originally fixed in formalin, which substantially degraded the DNA. We nonetheless managed to sequence two cytochrome c oxidase subunit I (COI) mini-barcodes: the universal mini-barcode at the 5′ end of the Folmer barcode (130 bp) and a newly proposed mini-barcode at the 3′ end of the Folmer barcode (296 bp). These mini-barcodes unambiguously confirmed our identifications. As an additional test, we also successfully sequenced these two mini-barcodes from the holotype of G. barretti, collected in 1855. We conclude by advocating the use of mini-barcodes on formalin-fixed or old specimens with degraded DNA.

Cephalopod biodiversity in the vicinity of Bear Seamount, western North Atlantic based on exploratory trawling from 2000 to 2014

Bear Seamount (BSM) is the most inshore seamount in the New England Seamount chain. It is located within the U.S. Exclusive Economic Zone and is contained within the recently established Northeast Canyons and Seamounts Marine National Monument. In 2000, the National Oceanic and Atmospheric Administration’s (NOAA) National Systematics Laboratory began an exploratory trawling program to document nekton diversity at BSM and its vicinity. Here, we summarize eight exploratory sampling cruises conducted between 2000 and 2014, and describe the cephalopod biodiversity and assemblage structure around BSM. Over the course of 174 deep–midwater and 56 bottom tows, 5088 cephalopods were identified, measured, and documented. In total, 77 species were collected at BSM; 75 species were collected from midwater tows and 28 from benthic tows. Rarefaction curves did not reach an asymptote, suggesting that additional sampling will collect more species. Seventeen species accounted for 75% of the total midwater and bottom catch, including: Illex illecebrosus (n = 605), Magnoteuthis magna (n = 568), Abraliopsis morisii (n = 518), Abralia redfieldi (n = 358), Mastigoteuthis agassizii (n = 336), Histioteuthis reversa (n = 273), Taonius pavo (n = 239), Haliphron atlanticus (n = 195), Brachioteuthis beanii (n = 160), Ornithoteuthis antillarum (n = 153), Pterygioteuthis gemmata (n = 141), Pyroteuthis margaritifera (n = 120), Vampyroteuthis infernalis (n = 101), Chiroteuthis veranyi (n = 33), Bolitaena pygmaea (n = 30), Graneledone verrucosa (n = 11), and Stauroteuthis syrtensis (n = 29). Non-metric multidimensional scaling (NMDS) of significant analysis of similarity (ANOSIM) results showed that the 2000 cruise was different from other years, meteorological winter was different from other seasons, and that day and night shallow samples were different from each other and all other depths. Based on seasonal size variation in the most abundant taxa, we propose hypotheses of year-round, winter, and spring spawning for future critical assessment. This extensive description of the offshore cephalopod assemblage may be used to assess vulnerability to future environmental changes and human activities.

On the recent destabilization of the Gulf Stream path downstream of Cape Hatteras

AbstractMapped satellite altimetry reveals interannual variability in the position of initiation of Gulf Stream meanders downstream of Cape Hatteras. The longitude where the Gulf Stream begins meandering varies by 1500 km. There has been a general trend for the destabilization point to shift west, and 5 of the last 6 years had a Gulf Stream destabilization point upstream of the New England Seamounts. Independent in situ data suggest that this shift has increased both upper‐ocean/deep‐ocean interaction events at Line W and open‐ocean/shelf interactions across the Middle Atlantic Bight (MAB) shelf break. Mooring data and along‐track altimetry indicate a recent increase in the number of deep cyclones that stir Deep Western Boundary Current waters from the MAB slope into the deep interior. Temperature profiles from the Oleander Program suggest that recent enhanced warming of the MAB shelf may be related to shifts in the Gulf Stream's destabilization point.

NOAA Research Vessel Explores Atlantic Ocean Seamounts

Mike Ford, a biological oceanographer with the National Oceanic and Atmospheric Administration (NOAA), sat rapt in front of a bank of high‐definition monitors. They provided live video and data feeds from a tethered pair of instrument‐laden remotely operated vehicles (ROVs) that were descending 4692 meters on their deepest dive ever. Their target: an unnamed and unexplored New England seamount discovered in the North Atlantic last year.

Seasonal occurrence of sperm whales (Physeter macrocephalus) around Kelvin Seamount in the Sargasso Sea in relation to oceanographic processes

Sperm whales (Physeter macrocephalus) are widely distributed in all oceans, but they are clumped geographically, generally in areas associated with high primary and secondary productivity. The warm, clear waters of the Sargasso Sea are traditionally thought to be low in productivity, however recent surveys have found large numbers of sperm whales there. The New England Seamount Chain bisects the north-western portion of the Sargasso Sea, and might influence the mesoscale eddies associated with the Gulf Stream; creating areas of higher productivity within the Sargasso Sea. We investigated the seasonal occurrence of sperm whales over Kelvin Seamount (part of the New England Seamount Chain) and how it is influenced by oceanographic variables. An autonomous recording device was deployed over Kelvin Seamount from May to June 2006 and November 2006 to June 2007. A total of 6505 hourly two-minute recordings were examined for the presence of sperm whale echolocation clicks. Sperm whales were more prevalent around Kelvin in the spring (April to June: mean=51% of recordings contained clicks) compared to the winter (November to March: mean=16% of recordings contained clicks). Sperm whale prevalence at Kelvin was related to chlorophyll-a concentration four weeks previous, eddy kinetic energy and month. The mesoscale activity associated with the Gulf Stream and the Gulf Stream׳s interaction with the New England Seamount Chain likely play an important role in sperm whale occurrence in this area, by increasing productivity and perhaps concentration of cephalopod species.

Widespread erosion and mass failure from the ∼51 Ma Montagnais marine bolide impact off southwestern Nova Scotia, Canada 1This article is one of a series of papers published in this CJES Special Issue on the theme of Mesozoic–Cenozoic geology of the Scotian Basin. 2Earth Sciences Sector Contribution 20120241.

The ∼51 Ma Montagnais impact crater on the outer Scotian Shelf is well known, but the potential effects from the impact event on the slope and rise seaward of the crater have, until now, remained poorly understood. Through detailed seismic stratigraphic correlation and ties to available wells, we define a threefold seismic stratigraphic subdivision for Upper Cretaceous to Eocene strata on the shelf and slope, calibrated to the most recent biostratigraphic results. Using this framework, we identify a number of depositional and erosional products that are temporally consistent with a late Ypresian impact event (within the limits of seismic and biostratigraphic resolution). We link a series of prominent failure scarps on the outer shelf and upper slope to a single widespread mass-transport deposit (MTD) on the lower continental slope, rise, and abyssal plain. Failed material amassed in a large debris field referred to here as the “Montagnais MTD”. It covers an area of ∼93 000 km2 and travelled up to 580 km from the impact site where its distal termination onlaps the New England Seamounts, making it one of the largest known debris avalanches on Earth. We interpret these deposits, and the associated pattern of erosion landward of them, as products of widespread margin collapse caused by a combination of ground shaking and ensuing tsunamis triggered by the Montagnais impact event. This study provides insight into the potential effects of outer-shelf marine impact events immediately downslope from impact sites, and their diminished effects with increasing distance along the margin.

A New Genus and Species of Bamboo Coral (Octocorallia: Isididae: Keratoisidinae) from the New England Seamounts

Sampling along the New England Seamount Chain has produced a large number of new octocoral species, especially of the bamboo corals in the subfamily Keratoisidinae. The new genus described here is unusual in that it branches from the internodes yet has sclerites at the base of the polyp body that are arranged obliquely, and in having tentacles that can be pulled completely into the top of the polyp over the retracted oral disk. The genus and species are characterized using both morphological and molecular data.

Genetic discontinuity among regional populations of Lophelia pertusa in the North Atlantic Ocean

Knowledge of the degree to which populations are connected through larval dispersal is imperative to effective management, yet little is known about larval dispersal ability or population connectivity in Lophelia pertusa, the dominant framework-forming coral on the continental slope in the North Atlantic Ocean. Using nine microsatellite DNA markers, we assessed the spatial scale and pattern of genetic connectivity across a large portion of the range of L. pertusa in the North Atlantic Ocean. A Bayesian modeling approach found four distinct genetic groupings corresponding to ocean regions: Gulf of Mexico, coastal southeastern U.S., New England Seamounts, and eastern North Atlantic Ocean. An isolation-by-distance pattern was supported across the study area. Estimates of pairwise population differentiation were greatest with the deepest populations, the New England Seamounts (average FST = 0.156). Differentiation was intermediate with the eastern North Atlantic populations (FST = 0.085), and smallest between southeastern U.S. and Gulf of Mexico populations (FST = 0.019), with evidence of admixture off the southeastern Florida peninsula. Connectivity across larger geographic distances within regions suggests that some larvae are broadly dispersed. Heterozygote deficien- cies were detected within the majority of localities sug- gesting deviation from random mating. Gene flow between ocean regions appears restricted, thus, the most effective management scheme for L. pertusa involves regional reserve networks.

Partners for life: a brittle star and its octocoral host

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 397:81-88 (2009) - DOI: https://doi.org/10.3354/meps08113 Partners for life: a brittle star and its octocoral host Celeste V. Mosher1, Les Watling1,2,* 1Darling Marine Center, University of Maine, 192 Clarks Cove Road, Walpole, Maine 04573, USA 2Present address: Department of Zoology, 152 Edmondson Hall, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA *Corresponding author. Email: watling@hawaii.edu ABSTRACT: Throughout the New England and Corner Rise seamounts of the western North Atlantic Ocean, several ophiuroid species are conspicuously epizoic on octocorals. One species, Ophiocreas oedipus, was found only on the chrysogorgiid octocoral Metallogorgia melanotrichos. Colonies of M. melanotrichos were collected from 11 seamounts during expeditions in 2003, 2004, and 2005 at depths between 1300 and 2200 m. O. oedipus is obligately associated with M. melanotrichos, leading a solitary existence on all octocorals observed. Evidence suggests that a young brittle star settles directly on a young octocoral and the 2 species then grow, mature, and senesce together. The brittle star benefits directly by being above the bottom for suspension feeding and is passively protected by the octocoral, but the latter, as far as we have been able to determine, seems neither to benefit nor be disadvantaged by the relationship. KEY WORDS: Octocoral · Brittle star · Ophiocreas · Metallogorgia · Commensal relationship · New England seamounts · Corner Rise seamounts Full text in pdf format PreviousNextCite this article as: Mosher CV, Watling L (2009) Partners for life: a brittle star and its octocoral host. Mar Ecol Prog Ser 397:81-88. https://doi.org/10.3354/meps08113 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 397. Online publication date: December 17, 2009 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2009 Inter-Research.

Commensalism between Juvenile Cusk Eels and Pancake Urchins on Western North Atlantic Seamounts

We describe a commensal relationship between small (approximately 6 to 9 cm) deep-sea cusk eels, one tentatively identified as Barathrites sp. (Osteichthyes: Ophidiidae), and pancake urchins, both Hygrosoma petersi and Phorosoma placenta (Echinodermata: Echinothuriidae). These interactions were observed in situ using a remotely operated vehicle (ROV), deployed at depths of 1410 to 1775 m on three seamounts in the western North Atlantic (Bear and Rehoboth seamounts in the New England Seamounts and Yakutat Seamount in the Corner Rise Seamounts). Full motion video and still frames documented individual cusk eels associated with urchins in open fine-grained sediment and coral rubble habitats. Cusk eels foraged around the periphery of urchins and took refuge at the base and among the long spines on the aboral surface. We suggest that such associations provide juvenile cusk eels with shelter from predators or flow (or both) and access to prey far from other forms of refugia.

Interannual variability of Gulf Stream warm-core rings in response to the North Atlantic Oscillation

Analysis of a quality-controlled database of Gulf Stream warm-core rings (WCRs) between 75° and 50°W during 1978–1999 demonstrates a significant correlation between WCR occurrences and variations in large-scale atmospheric forcing related to the state of the North Atlantic Oscillation (NAO). The mechanisms for linking the NAO with the rate of WCR occurrences are two-fold: (1) the influence of the NAO on Gulf Stream (GS) position, which could affect the interaction of the Gulf Stream with the New England Seamounts chain and thus allow for a higher/lower number of WCR occurrences; (2) the NAO-induced eddy kinetic energy (EKE) variability in the Gulf Stream region (GSR), which is indicative of the baroclinic instability processes necessary for WCR formation. Variability in GS movement is studied by analyzing annual mean positions of the Gulf Stream North Wall obtained from satellite-derived sea surface temperature (SST) frontal charts. Response of GSR EKE to fluctuations in the state of the NAO is examined with a numerical simulation of the North Atlantic basin from 1980–1999. The North Atlantic basin is simulated using a 1/6°-resolution eddy-resolving Regional Ocean Modeling System (ROMS) model that spins up with Southampton Oceanography Center (SOC) ocean-atmosphere atlas-derived atmospheric forcing fields. Model-derived EKE estimates are observed to be in good agreement with TOPEX/Poseidon altimeter-based EKE estimates as well as with results from other modeling studies for the North Atlantic basin. We suggest that lateral movement of the GS may not be the primary mechanism causing variation in the rate of WCR occurrences, because GS position is observed to respond at a lag of one year, whereas annual rates of WCR occurrences respond at 0-year lag to the NAO. Based on results from numerical simulations of the North Atlantic basin, adjustment to NAO-induced wind forcing is seen to impact the GSR EKE intensity and possibly the related baroclinic instability structure of the GS at 0-year lag. These results suggest that NAO-induced interannual variability in GSR EKE is the most likely mechanism affecting WCR occurrences. Numerical simulations show that high (low) phases in the state of the NAO exhibit higher (lower) EKE in the GSR, providing a greater (lesser) source of baroclinic instability to the GS front, possibly resulting in higher (lower) occurrences of WCRs.

The mean flow and variability of the Gulf stream-slopewater system from MICOM

The slopewater region is influenced by surface wind-driven, deep buoyancy-driven and shelf currents, whose complex interactions can affect both the northward heat transport and southward return flows. The mean flow and variability of the Gulf Stream-slopewater system are studied using four year outputs of Miami Isopycnic Coordinate Ocean Model (MICOM) realistic high-resolution simulation of the North Atlantic circulation. Special attention is focused on the eastward Slopewater Jet (SJ), a surface current characterized by a mean path coinciding with the strong outcropping temperature front in the slopewater. The water mass, path and transport of the SJ in MICOM are found to be in reasonable agreement with the existing observations. The modeled SJ is associated in part with a GS’ secondary branch, induced by a Taylor column effect of the New England Seamount Chain (NESC) on the upper GS. This upper-ocean-topographic coupling results in a spatial GS bifurcation, and advection of GS waters into the slopewater region shortly downstream of the NESC. An EOF analysis of the pycnocline depth confirms this tendency, as the first mode displays a qualitative dependence of the GS fan-shape streamline dispersion on the strength and intersecting latitude of the incident GS. Additionally, the model displays a strong influence of the Deep Western Boundary Current (DWBC) on the path of the SJ, by acting as a potential vorticity barrier. Important interactions between the two currents are suggested by the statistical EOF of the slopewater column, as in observations. Downstream of the NESC, the SJ transport variability is seasonal in MICOM, due to the north-south annual oscillation of the GS path and mergings with anticyclonic eddies. However, the variability of the SJ velocity profile is dominated (49% eigenvalue) by lateral translations of the current, at a 9-month timescale characteristic of GS meander-intensity variability. South of the Grand Banks, the transport variations of both the SJ and Labrador Current (LC) are captured by the first mode of the upper-slope water (37% of the variability), with predominant timescales corresponding to the upstream variability of the GS, and seasonality of the LC. Both modes are also in reasonable agreement with observations.

Temporal stability of the neodymium isotope signature of the Holocene to glacial North Atlantic

The neodymium isotopic composition of marine precipitates is increasingly recognized as a powerful tool for identifying changes in ocean circulation and mixing on million year to millennial timescales. Unlike nutrient proxies such as δ13C or Cd/Ca, Nd isotopes are not thought to be altered in any significant way by biological processes, and thus they can serve as a quasi‐conservative water mass tracer. However, the application of Nd isotopes in understanding the role of thermohaline circulation in rapid climate change is currently hindered by the lack of direct constraints on the signature of the North Atlantic end‐member through time. Here we present the first results of Nd isotopes measured in U‐Th‐dated deep‐sea corals from the New England seamounts in the northwest Atlantic Ocean. Our data are consistent with the conclusion that the Nd isotopic composition of North Atlantic deep and intermediate water has remained nearly constant through the last glacial cycle. The results address long‐standing concerns that there may have been significant changes in the Nd isotopic composition of the North Atlantic end‐member during this interval and substantiate the applicability of this novel tracer on millennial timescales for paleoceanography research.

New and Historical Records of Polychelid Lobsters (Crustacea: Decapoda: Polychelidae) from the Yale Peabody Museum Collections

Examination of the polychelid collections in the Division of Invertebrate Zoology of the Yale Peabody Museum yielded eight species of these deep-sea lobsters, including syntypes of Polycheles nanus (Smith, 1884). Three species are reported for the first time from the New England Sea-mounts: Pentacheles laevis Bate, 1878, P. validus A. Milne Edwards, 1880, and Polycheles talismani (Bouvier, 1917), with all but P. validus being represented in the collections by eryoneicus larvae as well as adults. Polycheles amemiyai Yokoya, 1933, is recorded for the first time from the Philippines and a misidentification of a Belize Polycheles typhlops Heller, 1862, by Boone (1927) is corrected. Additional specimens of Polycheles perarmatus Holthuis, 1952, and P. sculptus Smith, 1880, are reported from the Gulf of Mexico and the western Atlantic. All eryoneicus larvae are identified to species and a discussion of the problems associated with historical records of eryoneicus larvae is provided.

Studies on western Atlantic Octocorallia (Coelenterata: Anthozoa). Part 6: The genera Primnoella Gray, 1858; Thouarella Gray, 1870; Dasystenella Versluys, 1906

ABSTRACT The seven western Atlantic species belonging to three genera, Primnoella, Thouarella, and Dasystenella, are described and illustrated. Three new species of Thouarella are described, which constitute the first records of this genus for the northwestern Atlantic. An annotated and revised list of the 26 species of Thouarella is given. Most of the species included occur primarily in the southwestern Atlantic at depths of 50–5000 m; however, one species, Thouarella grasshoffi, is amphi-North Atlantic in distribution. Whereas most of the species included herein are small and inconspicuous, T. grasshoffi is fairly large and occurs abundantly on seamounts of the New England Seamount Chain as well as on eastern Atlantic seamounts. Specimens of all three genera are still relatively rare in museum collections.