Drift Lines Research Articles

Notes on the natural history and identity of the pelagic sea snake Hydrophis platurus (Serpentes: Elapidae) from Golfo Dulce, Puntarenas, Costa Rica

Introduction: The pelagic sea snake Hydrophis platurus has the broadest distributional range of all the snakes and is the only sea snake of tropical waters off the west coast of the Americas. Within the variation in the color pattern of this species, completely yellow specimens were considered very rare or occasional. However, a yellow pattern dominates a population established in the interior of the Golfo Dulce in the Southern Pacific of Costa Rica. Objective: We studied the abundance, activity patterns, morphometry, and feeding behavior of the yellow H. platurus within the Golfo Dulce. Methods: Between February 2009 and July 2018, we conducted surveys for sea snakes from a boat within the perimeter of the Golfo Dulce. Results: Adults from the gulf population are smaller than the bicolor oceanic population, with females having larger bodies. Sea snakes within the gulf float and move with surface currents without being linked to drift lines and debris. These snakes are mainly found in clean, calm waters with little turbulence. They feed on a wide diversity of small fish, which they capture using passive stalking predatory behaviors floating on the surface. Prey are quickly captured and swallowed alive. This species has an almost total absence of predation, a pattern that extends to this yellow population. Conclusions: The characteristics of the gulf and the direction and strength of the surface currents at its entrance might restrict the transit of this yellow population to the outside and the entry of the bicolored snakes of the oceanic population. We do not consider making taxonomic changes in this Golfo Dulce population prudent. This yellow population is relatively common within the basin. However, the high tourist traffic and other activities are risk factors for its conservation. Protection policies must be created to preserve and protect this small population of yellow sea snakes unique within this species' distribution range.

Distribution characteristics of vegetation on the drift lines at small beaches in the coastal area of the Seto Inland Sea

Distribution characteristics of vegetation on the drift lines at small beaches in the coastal area of the Seto Inland Sea

The mechanical alignment of dust (MAD)

Context. Observations of polarized light emerging from aligned dust grains are commonly exploited to probe the magnetic field orientation in astrophysical environments. However, the exact physical processes that result in a coherent large-scale grain alignment are still far from being fully constrained. Aims. In this work, we aim to investigate the impact of a gas-dust drift on a microscopic level, potentially leading to a mechanical alignment of fractal dust grains and subsequently to dust polarization. Methods. We scanned a wide range of parameters of fractal dust aggregates in order to statistically analyze the average grain alignment behavior of distinct grain ensembles. In detail, the spin-up efficiencies for individual aggregates were determined utilizing a Monte Carlo approach to simulate the collision, scattering, sticking, and evaporation processes of gas on the grain surface. Furthermore, the rotational disruption of dust grains was taken into account to estimate the upper limit of possible grain rotation. The spin-up efficiencies were analyzed within a mathematical framework of grain alignment dynamics in order to identify long-term stable grain alignment points in the parameter space. Here, we distinguish between the cases of grain alignment in the direction of the gas-dust drift and the alignment along the magnetic field lines. Finally, the net dust polarization was calculated for each collection of stable alignment points per grain ensemble. Results. We find the purely mechanical spin-up processes within the cold neutral medium to be sufficient enough to drive elongated grains to a stable alignment. The most likely mechanical grain alignment configuration is with a rotation axis parallel to the drift direction. Here, roundish grains require a supersonic drift velocity, while rod-like elongated grains can already align for subsonic conditions. We predict a possible dust polarization efficiency in the order of unity resulting from mechanical alignment. Furthermore, a supersonic drift may result in a rapid grain rotation where dust grains may become rotationally disrupted by centrifugal forces. Hence, the net contribution of such a grain ensemble to polarization drastically reduces. In the presence of a magnetic field, the drift velocity required for the most elongated grains to reach a stable alignment is roughly one order of magnitude higher compared to the purely mechanical case. We demonstrate that a considerable fraction of a grain ensemble can stably align with the magnetic field lines and report a possible dust polarization efficiency of 0.6–0.9, indicating that a gas-dust drift alone can provide the conditions required to observationally probe the magnetic field structure. We predict that magnetic field alignment is highly inefficient when the direction of the gas-dust drift and magnetic field lines are perpendicular. Conclusions. Our results strongly suggest that mechanical alignment has to be taken into consideration as an alternative driving mechanism where the canonical radiative torque alignment theory fails to account for the full spectrum of available dust polarization observations.

Dynamic responses of the active hydraulic pneumatic tensioner for a TLP in internal solitary waves

Tensioner system is the key connection device used to connect the platform and the top tensioned riser. An internal solitary wave (ISW) can cause serious damage to the tensioner system due to rough drift or broken mooring lines. In this paper, an active control tensioner system is proposed under the action of the ISW. By using the coupling model of the Tension Leg Platform (TLP), the dynamic response of the platform with the active tensioner and the passive tensioner under different control modes are studied. It is concluded that the surge/sway and heave motions of the platform are significantly affected by the ISW. Compared with the passive tensioner, the active tensioner obviously reduces the amplitude of the piston rod motion at low frequency and is more stable at high frequency.

RESEARCH OF LONG-TERM DRIFT OF THE NATIONAL INDUCTANCE STANDARD

Inductance measurements is important for all branches of technology related to the application of electricity: energy and electronics, radio and television, transport and communication, and scientific research. Electromechanical devices and electronic components can be characterized using impedance measurements to identify the parameters of their equivalent electrical model. New inductance measurement methods are being developed in specific fields of activity. Manufacturers of standards and measuring instruments of inductance develop special handbooks outlining various methods of inductance measurement. The State Primary Standard of Ukraine for inductance and loss angle tangent reproduces and transmits a unit of inductance in the range from 1∙10-6 H to 10 H at a frequency of 1 kHz. It is keeping in the SE “Ukrmetrteststandard” and participated in several comparisons of national standards within the framework of the activities of regional metrological organizations. The calibration and measurement capabilities of inductance measurement of national laboratories of different countries were studied to analyze and compare the capabilities of the national standard with the standards of other countries. Long-term instability studies of inductance measures of 1 mH, 10 mH and 100 mH, which are part of the national standard unit of inductance, have been conducted. The research period covered from 2009 to 2022. It was established that the drift lines of the specified inductance measures can be described using linear approximations. The rationale for choosing inductance measures of 10 mH and 100 mH for their use as transmission standards in the calibration of standards, which were organized and conducted by SE “Ukrmetrteststandard” as their pilot laboratory, is given.

Hylotelephium maximum from Coastal Drift Lines Is a Promising Zn and Mn Accumulator with a High Tolerance against Biogenous Heavy Metals

Heavy metal tolerance and accumulation potential are the two characteristics most important for plant use in phytoremediation technologies. Therefore, the aim of the present study was to characterize the tolerance of Hylotelephium maximum from coastal drift line vegetation against the biogenous heavy metals Cu, Zn, and Mn and its metal accumulation potential in controlled conditions. Plants were propagated vegetatively and cultivated in an automated greenhouse in a vegetative state (Experiment 1; Cu, Zn, and Mn) and in flowering-inducing conditions (Experiment 2; Mn gradient). In Experiment 1, total shoot biomass was negatively affected only by Mn at 1.0 g L−1, but root growth was significantly inhibited by all metals at this concentration. Plants accumulated 250 mg kg−1 Cu, 3200 mg kg−1 Zn, and >11,000 mg kg Mn−1 in their leaves. In Experiment 2, only new shoot growth was significantly suppressed at 0.5 g L−1 Mn. At the highest concentrations, shoot biomass progressively declined at the level of inhibition of flower and stem growth. Visual toxicity symptoms of Mn appeared 2 weeks after full treatment on leaves of 2.0 g L−1 treated plants as black dots along the main veins and spread over the leaf surface with time. The maximum Mn accumulation capacity was reached in leaves (15,000 mg kg−1), together with a high translocation factor and bioconcentration factor. The obtained results suggest that the particular accession of H. maximum has very good potential for practical phytoremediation purposes.

Evaluation of phenolic content of wrack debris on estuarine beaches: The effect on upper beach macrofauna

AbstractWrack supply represents the main organic input in sandy beaches ecosystems and is a common feature of beaches around the world. The chemical composition of the wrack is important in determining the extent and rate of the decay; in particular, phenolic compounds may affect consumption rates by wrack‐associated macrofauna and, consequently, modify the nutrient processing and recycling in sandy beaches. The aim of this research was to investigate the possible links between phenolic content of wrack supplies and the macrofaunal community inhabiting them. To achieve this, patches of wrack in three beaches of the NW coast of Spain were analysed and the phenolic contents and macrofaunal distribution, both at spatial and temporal scales, were assessed. Wrack and macrofaunal samples were collected along two shore‐parallel transects, coinciding with the wrack lines of previous tidal deposition. The results showed a general spatial distribution in the phenolic content of the beach‐cast according to their tidal position on the beach. Thus, two distinct zones were identified: the “spring‐tide deposited” zone located in the upper beach close to the base of the dunes and composed by wrack material with the lowest phenolic concentrations; and a “freshly deposited” zone with wrack deposits containing the highest concentrations of deterrent compounds. Nevertheless, only supratidal grazers, mostly linked to fresh deposits, have shown a slightly negative association between their abundance and the increasing phenolic contents of the stranded macroalgae. The lack of a consistent pattern in macrofaunal occupation of fresh and decayed drift lines detected suggests the species could be selecting habitats for reasons other than phenolic content.

Short communication: Driftwood provides reliable chronological markers in Arctic coastal deposits

Abstract. Originating from the boreal forest and often transported over large distances, driftwood characterizes many Arctic coastlines. Here we present a combined assessment of radiocarbon (14C) and dendrochronological (ring width) age estimates of driftwood samples to constrain the progradation of two Holocene beach-ridge systems near the Lena Delta in the Siberian Arctic (Laptev Sea). Our data show that the 14C ages obtained on syndepositional driftwood from beach deposits yield surprisingly coherent chronologies for the coastal evolution of the field sites. The dendrochronological analysis of wood from modern drift lines revealed the origin and recent delivery of the wood from the Lena River catchment. This finding suggests that the duration of transport lies within the uncertainty of state-of-the-art 14C dating and thus substantiates the validity of age indication obtained from driftwood. This observation will help us better understand the response of similar coastal systems to past climate and sea-level changes.

Coastal plant species as electrolytophytes: effect of NaCl and light intensity on accumulation characteristics of Atriplex glabriuscula from coastal drift lines

Coastal plant species as electrolytophytes: effect of NaCl and light intensity on accumulation characteristics of Atriplex glabriuscula from coastal drift lines

A new subspecies of sea snake, Hydrophis platurus xanthos, from Golfo Dulce, Costa Rica.

We describe a distinctive new subspecies of sea snake from the occasionally anoxic inner-basin waters of Golfo Dulce, Costa Rica, based on combined data garnered between 2010 and 2017 for 154 specimens, 123 free-ranging and 31 museum-held. The yellow sea snake, Hydrophis platurus xanthos Bessesen & Galbreath, subsp. n., is diagnosed by a notably smaller body size and nearly uniform yellow coloration, which contrasts with the black and yellow striae and tail spots or bands typical of the species. Within the modest geographic range (circa 320 km2), nearly all specimens possess both diagnostic character states. Bathymetrics appear to restrict genetic flow between this allopatric population and conspecifics in the broader Eastern Pacific. In perspicuous contrast to typical H. platurus, H. p. xanthos shows no association with drift lines, and feeds at night in turbulent waters, assuming a sinusoidal ambush posture never previously reported for the species. This evolutionarily significant unit (ESU) warrants taxonomic recognition and active protection.

Synecology of Cutandia maritima (L.) Barbey, a rare psammophytic species along the Montenegrin Coast (East Adriatic Coast)

Abstract Cutandia maritima is a circum-Mediterranean species that inhabits sandy dunes along the coast line. It is fairly frequent on the western Adriatic coast but fairly rare and possibly even non-native in the east. In Croatia, it was discovered in 1990 in Crnika Bay on the island of Rab, which was considered until 2005 to be the only site on the eastern Adriatic coast from the Gulf of Trieste in the north to Corfu in the south. In 2009, the species was briefly reported for Velika plaža (Long Beach) in Ulcinj (Montenegro) but without details about the habitat type and synecology. The aim of this paper is thus to provide a deeper insight into the ecology and synecology of C. maritima in the eastern Adriatic part of the distribution area. On Velika plaža in Ulcinj, the species was found along the whole sea-inland gradient of sand dunes, in various types of vegetation: [1210] - annual vegetation of drift lines, [2110] - embryonic shifting dunes, [2120] - shifting dunes with Ammophila arenaria (white dunes), [2220] - dunes with Euphorbia terracina, [2130*] - fixed coastal dunes with herbaceous vegetation (grey dunes), and also [2190] - humid dune slacks.

WD 1145+017 photometric observations during eight months of high activity

WD 1145+017 was observed from 2015 November to 2016 July for the purpose of characterizing transit behavior of the white dwarf by dust clouds thought to be produced by fragments of an asteroid in close orbit with the star. Fortuitously, most of these observations were carried out during a time when the overall `dip' activity was dramatically enhanced over that during its discovery with Kepler K2. By the end of our reported observations the dip activity had declined to a level close to its K2 discovery state. Three notable events were observed. In 2016 January a large number of dust clouds appeared that had an orbital period of 4.4912 hours, and this event also marked the end of a 3-month interval dominated by the K2 `A' period. The second event was a 2016 April 21 appearance of four dip features with drift lines in a waterfall diagram (date vs. phase) that diverged from their origin date, at a location away from the `A' asteroid, and which lasted for two weeks. The third event was the sudden appearance of a dip feature with a period of 4.6064 hours, which is essentially the same as the K2 `B' period. The evolution of dip shape, depth, and total fade amount provide constraints on dust production and loss mechanisms. Collisions can account for the sudden appearance of dust clouds, and the sudden increase in dust amount, but another mechanism for continual dust production is also required.

How does dune morphology shape coastal EC habitats occurrence? A remote sensing approach using airborne LiDAR on the Mediterranean coast

We examined the relationship between coastal habitats (sensu European Union Habitats Directive) and local dune morphology along a Mediterranean coastal dune system by integrating field collected vegetation data and remotely sensed imagery. Specifically, we described the morphological profile of each EC habitat based on the morphological variables that are most likely to affect their occurrence, including elevation, slope, curvature, northness, eastness and sea distance. In addition, we assessed the role and strength of each morphological variable in determining the occurrence of EC habitats.We used 394 random vegetation plots representative of six EC habitats (Habitat 1210: “Annual vegetation of drift lines”; Habitat 2110: “Embryonic shifting dunes”; Habitat 2120: “Shifting dunes along the shoreline with Ammophila arenaria”; Habitat 2210 and 2230: “Crucianellion maritimae fixed beach dunes” and “Malcolmietalia dune grasslands”; Habitat 2250: “Coastal dunes with Juniperus spp.”; Habitat 2260: “Cisto-Lavanduletalia dune sclerophyllous scrubs”) found along the Tyrrhenian coast of central Italy. We derived each morphological variable from a DTM (Digital Terrain Model) obtained from 2-m resolution LiDAR (Light Detection And Range) images. The mean value of each variable was calculated at different spatial scales using buffer areas of increasing radius (2m, 4m, 8m) around each vegetation plot. Mean morphological values for each EC habitat were compared using Kruskal-Wallis rank test. The role and strength of the relationship between habitat type and the morphological variables were assessed using Generalized Linear Models.EC habitats occur differentially across dune morphology, and the role and strength of each morphological variable define habitat specificity. Dune elevation and sea distance were determined to be the key factors in shaping EC habitat occurrence along this section of the Mediterranean coast. Identification of the close relationship between habitat type and morphological variables deriving from airborne LiDAR imagery points to the high potential of such remote sensing tool for analyzing and monitoring the integrity of coastal dune ecosystems. As airborne LiDAR enables the rapid collection of extremely accurate topographic data over large areas, it also offers useful information for the management of these threatened and fragile ecosystems.

Foredune psammophilous communities and coastal erosion in a stretch of the Ligurian sea (Tuscany, Italy)

Italy sandy coasts are characterised by a great diversity of habitats and, at the same time, many of these coastal stretches are in erosive condition. Therefore, it is important to understand, in areas where marine erosion is particularly strong, which are the most vulnerable and most threatened habitats. The paper sets out data from the survey of foredune habitats (annual vegetation of drift lines, embryonic dunes, mediterranean white dunes, sensu Directive 92/43/EEC) in the San Rossore Estate sandy coast (Northern Tuscany, Italy) strongly subjected to erosion. The surveys, in addition to updating the information collected, aim to point out the arrangement of these habitats in relation to coastal retrogradation and foredune erosion, in order to identify appropriate management tools for mitigating disturbance factors. The surveys, conducted in the field and by photo-interpretation, revealed the presence of foredune plant communities hardly referable, from the phytosociological point of view, to known associations of neighboring coasts. The Cakile maritima plant communities of annual vegetation of drift lines, the Elymus farctus/Othantus maritimus phytocoenosis of embryonic dune and the Ammophila arenaria/Euphorbia paralias communities of white dunes, are markedly altered in their floristic composition; the coverage and distribution of the different plant communities are in a highly differentiated manner according to erosion gradients. The understanding of dynamics of alteration of psammophilous plant communities in relation to coastal erosion may suggest potential aid in the management actions aimed at containing the transformations or and/or useful for the restoration of the same habitats.

On the Abundance of a Pelagic Sea Snake

Abstract We quantified the abundance of pelagic sea snakes, Hydrophis (= Pelamis) platurus, while following slicks that formed drift lines during 3 yr of research in the Golfo de Papagayo, Costa Rica. The number of snakes we observed floating on slicks varied greatly and ranged from 0 to 1,029 per hour. The largest number we observed was highly unusual in recent experience but comparable to earlier reports of sea snake aggregations in the historical literature. Snakes were more abundant on slicks with flotsam during early morning hours on clear, calm days. However, ‘decisions' of sea snakes to spend time floating on slicks are also influenced by other factors that are not known or are poorly understood. Neither temperature nor salinity influenced the number of snakes we observed within the range of the parameters we encountered. We observed only a single snake during 13 days of searching during which there were red tide conditions with cold and turbid water disturbed almost daily by high winds. We also co...

The invasive ergot Claviceps purpurea var. spartinae recently established in the European Wadden Sea on common cord grass is genetically homogeneous and the sclerotia contain high amounts of ergot alkaloids

A well-established population of Claviceps purpurea var. spartinae R.A. Duncan & J.F. White was found on the invasive common cord-grass Spartina anglica C.E. Hubbard at two localities on the German North Sea coast. Additionally, 25 populations of S. anglica with an average air-line distance of 50 km between them along the coastline, starting from the Netherlands via the German coastline up to Denmark, were investigated. All S. anglica populations were heavily infected with C. purpurea var. spartinae (lineage G3). Genetic characterization of the C. purpurea DNA using Amplified Fragment Length Polymorphism (AFLP) and Internal Transcribed Spacer (ITS) analysis clearly indicated that all populations collected at the Wadden Sea were grouped in the same epidemic clade. Comparisons with reference strains indicated that the isolates along the Wadden Sea belonged to the clade also found in Ireland and Wales. The ergot alkaloid pattern is very similar in all genotypes. Ergocristine, α-ergocryptine and their epimers were identified in the samples in high amounts comparable to average values in sclerotia found on rye. The sclerotia of C. purpurea var. spartinae are able to float on the water for several months and could thereby be distributed over large distances by seawater. The sclerotia found in the drift lines still contain the equally high contents of ergot alkaloids as those collected directly from the plants. Current data form the basis for risk assessments and predictions about further spreading of C. purpurea var. spartinae on S. anglica.

Differences between the rhizosphere microbiome of Beta vulgaris ssp. maritima-ancestor of all beet crops-and modern sugar beets.

The structure and function of the plant microbiome is driven by plant species and prevailing environmental conditions. Effectuated by breeding efforts, modern crops diverge genetically and phenotypically from their wild relatives but little is known about consequences for the associated microbiota. Therefore, we studied bacterial rhizosphere communities associated with the wild beet B. vulgaris ssp. maritima grown in their natural habitat soil from coastal drift lines (CS) and modern sugar beets (Beta vulgaris ssp. vulgaris) cultivated in CS and potting soil (PS) under greenhouse conditions. Analysis of 16S rRNA gene fingerprints and pyrosequencing-based amplicon libraries revealed plant genotype- and soil-specific microbiomes. Wild beet plants harbor distinct operational taxonomic units (OTUs) and a more diverse bacterial community than the domesticated sugar beet plants. Although the rhizospheres of both plant genotypes were dominated by Proteobacteria and Planctomycetes, 37.5% of dominant OTUs were additionally detected in the wild beet rhizosphere. Analysis of the cultivable fraction confirmed these plant genotype-specific differences at functional level. The proportion of isolates displayed in vitro activity against phytopathogens was lower for wild beet (≤45.8%) than for sugar beet (≤57.5%). Conversely, active isolates from the wild beet exhibited stronger ability to cope with abiotic stresses. From all samples, active isolates of Stenotrophomonas rhizophila were frequently identified. In addition, soil type-specific impacts on the composition of bacterial communities were found: Acidobacteria, Chloroflexi, and Planctomycetes were only detected in plants cultivated in CS; whereas Bacteroidetes and Proteobacteria dominated in PS. Overall, in comparison to modern sugar beets, wild beets were associated with taxonomically and functionally distinct microbiomes.

Wind-Driven Dynamics of Beach-Cast Wrack in a Tide-Free System

Whereas wrack dynamics on tidally influenced beaches have been studied to some detail, essentially nothing is known about how drift lines in tide-free coastal systems vary in space and time. We provide evidence for high spatial and temporal dynamics of beach-cast wrack on a sand beach in the Western Baltic Sea. Over the course of one year, the amount of weekly deposited macrophyte wrack fluctuated from zero to 3000 g·m-1 shoreline. Wrack mostly accumulated just above the waterline. Part of the beach-cast wrack is frequently re-suspended into coastal water upon extreme high water level events, or wrack patches are translocated landwards by wind-driven changes in water level or along the shoreline by winds. Consequently, the deposited wrack does accumulate, but a steady-state of ca 400 g·m-1 builds up within 2 - 3 weeks. Eelgrass wrack buried in sand decomposed almost twice as fast as on top of the sand or re-suspended in water. Fragmentation of leaves promoted decomposition only when wrack remained on the sand surface. The spatial and temporal distribution of this valuable source of organic matter is unpredictable and depends on wind and wind-driven waves.

Reply to: Frisch and Dawes (DOI 10.1007/s00531-013-0980-7) discussion on The rotations opening the Central and Northern Atlantic Ocean: compilation, drift lines, and flow lines (DOI 10.1007/s00531-012-0860-6)

Reply to: Frisch and Dawes (DOI 10.1007/s00531-013-0980-7) discussion on The rotations opening the Central and Northern Atlantic Ocean: compilation, drift lines, and flow lines (DOI 10.1007/s00531-012-0860-6)

The rotations opening the Central and Northern Atlantic Ocean: compilation, drift lines, and flow lines (Int J Earth Sci 102:1357–1376)

Strait and marked the Wegener Fault. Figure 1b depicts the present-day geography and geology of the region modified from Dawes (2009, Fig. 9). The mismatch between Ellesmere Island and Greenland in Fig. 1a is immediately apparent from the disruption of the two sedimentary basins—the Mesoproterozoic Thule and Paleozoic Franklinian—that straddle nares Strait. The component of the Thule Basin on Greenland is displaced from that on Ellesmere Island. The regional architecture of the Franklinian Basin depicted in Fig. 1b by cambrian to Devonian markers in Ellesmere Island and Greenland is destroyed and the cambro-Silurian, folded, deep-water trough of the Franklinian Basin on Greenland strikes into Paleoproterozoic gneiss on Ellesmere Island. Other misfits on a more detailed scale are listed by Dawes (2009). In addition, closure of the major seaways flanking Devon Island (Lancaster and Jones Sounds) likewise results in gross mismatches within canadian geology. Similar problems arising from the undoing of harmonious geology mar Greiner and neugebauer’s reconstructions at 84 and 52.65 Ma. Saalmann et al. (2005) described a Paleogene, nEtrending, strike-slip fault zone and later SE-directed thrusting on land in a 100-km-long stretch of the nE Ellesmere Island coastline. They considered this deformation to be a manifestation of the Wegener Transform Fault and plate boundary but admitted that the fault could not be traced farther south through southern nares Strait into Baffin Bay. Greiner and neugebauer have used Saalmann et al.’s findings to support their case for convergence of Greenland and Ellesmere Island and large-scale displacement along the Wegener Fault but fail to acknowledge that these Paleogene tectonic features are of limited regional significance and that, in any event, the amount of strike slip recorded on land is insufficient to account for the separation of Greenland from north America by spreading in Baffin Bay. Greiner and neugebauer (2013) have modeled the opening of the central and northern Atlantic Ocean using a computer program that generates paleogeographic reconstructions based on Euler rotational data, which in turn are derived from magnetic anomalies flanking oceanic spreading ridges. Here, we confine ourselves to a critique of Greiner and neugebauer’s results for the nares Strait—northern Baffin Bay region bordered by Greenland and the eastern canadian High Arctic. Reconstructions at or before 175, 84, and 52.65 Ma are shown in Greiner and neugebauer’s Figures 5, 6, 9, and 10. All these are strictly paleogeographic representations; none shows any surface geological feature. Greiner and neugebauer a priori consider Greenland to be an independent tectonic plate separated from Ellesmere Island—part of the north American plate—by a transform fault, the Wegener Fault, running through nares Strait. They accept the Wegener Fault as a proven structure and overlook abundant evidence that it is hypothetical (Oakey and Damaske 2006; Harrison 2006; Dawes 2009; Hansen et al. 2011; Rasmussen and Dawes 2011). They cite only one reference to geology relevant to their reconstructions, viz. Saalmann et al. (2005), to which we will return below. Figure 1a is a reproduction of part of Greiner and neugebauer’s Fig. 9 (reconstruction before 175 Ma) with four geological provinces shown, as well as their postulated north American plate boundary coinciding with nares