the lilliput effect in the aftermath of the end permian extinction event early triassic animal body fossils and trace fossils are small relative to those in older and younger intervals size decreases sharply through the end permian extinction event and permian triassic boundary and the smallest sizes are encountered in the parvus and isarcica zones of the earliest induan animals appearing within these two zones are also exceedingly small compared to younger congenerics and conspecifics temporary dramatic size decrease of surviving taxa in the immediate aftermath of the extinction event is an example of the lilliput effect coined by urbanek a 1993 biotic crises in the history of upper silurian graptoloids a palaeobiological model historical biology 7 29 50 body size increases somewhat from the carinata zone mid induan but remains depressed for the duration of the early triassic and pre extinction sizes are not commonly recorded until at least the middle triassic marine and terrestrial faunas appear to be similarly affected the lilliput effect and longer term size reduction could be the result of several factors environmental parameters such as marine anoxia due to low atmospheric concentrations of oxygen at this time coupled with sluggish ocean circulation in a greenhouse world and food shortage are the likely proximal causes for the early triassic lilliput effect no single cause can explain all the observations and a combination of factors are likely to be involved

organized structures in subsurface bubble clouds langmuir circulation in the open ocean observations of the movement and distribution of subsurface bubbles reveal the structure of coherent motions near the ocean surface the measurements were obtained in the open ocean from a freely drifting self contained acoustical instrument equipped with side scan sonar dual frequency echo sounders and ambient sound recording systems the bubble clouds are organized into long narrow plumes aligned with the wind consistent with windrows caused by langmuir circulations they have widths of about 3 to 5 m and lengths up to 100 m with multiple scales coexisting their mean separation depends upon wind speed below 5 m s 1 mean spacings were about 5 m increasing to 10 m when winds exceeded 10 m s 1 the maximum depth to which the plumes were observed to penetrate depended to some extent on wind speed with the greatest penetrations of 12 m occurring at the highest wind speeds 13 m s 1 however the time averaged depth of observed bubble plume penetration bears only a weak dependence on wind speed whenever winds exceeded 5 m s 1 a mean penetration depth of 6 m was observed associated with these bubble plumes were maximum downward velocities of about 0 06 m s 1 these speeds were detected at 8 m depth in the center of the plumes magnitudes decreased to zero near the surface and horizontally toward the boundaries of the plumes

on the relative role of sea surface roughness and bubble plumes in shallow water propagation in the low kilohertz region in the low kilohertz frequency range acoustic transmission in shallow water deteriorates as wind speed increases although the losses can be attributed to two environmental factors the rough sea surface and the bubbles produced when breaking or spilling waves are present the relative role of each is still uncertain for simplicity in terms of an average bubble population the time and space varying assemblage of microbubbles is usually assumed to be uniform in range and referred to as the subsurface bubble layer however the bubble population is range and depth dependent in this article results of an experiment weston et al philos trans r soc london ser a 265 507 606 1969 involving fixed source and receivers and observations during an extended period of time under varying weather conditions are re examined by exercising a numerical model that allows for the dissection of the problem calculations are made at 2 and 4 khz it is shown that at these frequencies and at wind speeds capable of generating breaking waves the main mechanism responsible for the excess loss in the shallow water waveguide is the patchy nature of the subsurface bubble field refraction and attenuation within the pockets of high void fraction are minor contributors to the losses

exceptional fossil preservation during co2 greenhouse crises abstract exceptional fossil preservation may require not only exceptional places but exceptional times as demonstrated here by two distinct types of analysis first irregular stratigraphic spacing of horizons yielding articulated triassic fishes and cambrian trilobites is highly correlated in sequences in different parts of the world as if there were short temporal intervals of exceptional preservation globally second compilations of ages of well dated fossil localities show spikes of abundance which coincide with stage boundaries mass extinctions oceanic anoxic events carbon isotope anomalies spikes of high atmospheric carbon dioxide and transient warm wet paleoclimates exceptional fossil preservation may have been promoted during unusual times comparable with the present co 2 greenhouse crises of expanding marine dead zones oceanic acidification coral bleaching wetland eutrophication sea level rise ice cap melting and biotic invasions

size variation of conodonts during the smithian spathian early triassic global warming event the early triassic smithian spathian boundary ssb crisis coincided with an episode of extreme warmth a high resolution stratigraphic framework comprising six conodont zones is provided in the jiarong section nanpanjiang basin in south china detailed size measurements of 441 conodont elements of the closely related genera neospathodus triassospathodus and novispathodus show for the first time that this clade suffered a temporary but significant size reduction during the ssb crisis the size reduction of conodonts was probably caused by an episode of global warming

diversity dynamics of early jurassic ostracods of the cordillera iberica spain and the re evaluation of the pliensbachian toarcian mass extinction the extinction and recovery of ostracoda at the pliensbachian toarcian p t boundary are analyzed based on a database of taxonomically revised pliensbachian to toarcian transition ostracod assemblages in contrast to earlier assertions the results of this study indicate that ostracod extinction rates were significant in comparison with other marine invertebrates an extinction rate of 54 has been calculated for upper pliensbachian ostracod species occurring in more than one section diversification took place in the latest pliensbachian spinatum zone and early toarcian tenuicostatum zone whereas diversity decrease occurred in the middle early toarcian strangewaysi subzone serpentinus zone this notable diversity decline in the early toarcian corresponds to a global mass extinction time whose peak has been documented in the tenuicostatum zone meanwhile the ostracod mass extinction occurred within the serpentinus zone and was followed by radiation and recovery in the succeeding bifrons zone s

measurements of turbulence in the upper ocean mixing layer using autosub abstract the rate of dissipation of turbulent kinetic energy has been measured with airfoil probes mounted on an autonomous vehicle autosub on constant depth legs at 2 10 m below the surface in winds up to 14 m s 1 the observations are mostly in an area limited by fetch to 26 km where the pycnocline depth is about 20 m at the operational depths of 1 55 15 9 times the significant wave height hs and in steady winds of about 11 6 m s 1 when the wave age is 11 7 17 2 dissipation is found to be lognormally distributed with a law of the wall variation with depth and friction velocity breaking waves leaving clouds of bubbles in the water are detected ahead of the autosub by a forward pointing sidescan sonar and the dissipation is measured when the clouds are subsequently reached bands of bubbles resulting from the presence of langmuir circulation are identified by a semiobjective method that seeks continuity of band structure recognized by both forward and sideways pointing sidescan sonars the times

acoustic observation of oil slicks at sea the results of an open sea experiment devised to investigate the feasibility of detecting and monitoring oil slicks by sonar through their effect on the acoustic backscatter signal are presented the analysis carried out over an angular range 10 to 70 from the horizontal reveals a reduction in backscatter from the slick the reduction in the mean backscatter shows an angular dependence which reaches a maximum in the range 45 to 65 a gradual decrease of as wind speed decreased and as the slick developed was also observed comparison of the acoustic data with ku band radar reflection from an oil covered surface under similar wind speed conditions shows that differential radar backscatter from oil slicks may exceed that of sonar by a factor 5

runoff generation from successive simulated rainfalls on a rocky semi arid mediterranean hillslope runoff generation in a mediterranean carbonate rock environment the judaean mountains west bank and israel was studied by a 2 day sprinkling experiment on an 18 x 10 m 2 plot during the first day three spells of 24 1 mm h 1 12 3 mm 27 8 mm h 1 12 3 mm and 14 4 mm h 1 12 5 mm were applied almost saturating the runoff plot on the second day 20 h later two spells of 18 7 mm h 1 34 3 mm and 35 2 mm h 1 25 4 mm followed surface runoff was a combination of infiltration excess runoff from rocky portions of the plot and saturation excess runoff from areas covered by soil soil saturation was accelerated by lateral runoff from adjacent rocky areas once the plot was saturated 80 90 of the applied rainfall became surface runoff significantly different concentrations of chloride sulphate and nitrate ions in the sprinkled water on two successive days served as tracers during the second day a two component hydrograph separation pointed to the importance of shallow reservoirs playing active parts in runoff generation about 14 of the flow collected during the second day originated from water applied during the first day during the second day of sprinkling both water sources obviously mixed in saturated soil reservoirs and contributed in variable percentages to surface flow it is hypothesized that at least during high magnitude rainfall the steep rocky slopes investigated might be regarded as flood generating zones rather than areas of pronounced recharge into the underlying yarkon taninim aquifer

chemical and isotopic indicators of point source recharge to a karst aquifer south australia abstract several hundred sinkholes swamps and open drainage boreholes throughout the semi arid to sub humid areas of the southeast of south australia are potential recharge sites to the upper part of the gambier limestone aquifer this paper presents the results from a hydrochemical cl and carbonate chemistry and isotopic 2 h s 18 o and 36 cl study used to estimate the importance of localised recharge from these point source features to the karstic groundwater system results show that water recharging the groundwater via point source features is detectable only on a local scale chemical and isotopic compositions of groundwaters more than 150 m from the larger of the point source features are indistinguishable from regional groundwater compositions chloride concentrations carbonate chemistry and isotope data show that annual input of water via point sources contributes less than 10 of total recharge with diffuse recharge providing the remainder to the study area as a whole point source recharge is generally intermittent and was observed to occur only for a few days at a time and only after a threshold of sustained rainfall had been exceeded i e greater than 2 5 mm day 1 for more than 3 days the stable isotopic composition of waters recharging via sinkholes tends to be enriched in 2 h and 18 o relative to regional groundwater and local precipitation this is probably caused by a small degree of evaporation less than 596 of water falling within the catchment occurring during winter at high relative humidity greater than 9596 before recharge 36 cl from weapons testing is detectable in groundwaters near sinkholes and indicates significant retardation of cl within soils of the respective sub drainage systems recharge has therefore occurred within the past 30 years but cannot be quantified with any reliable precision from the 36 cl data

the effect of langmuir circulation on the distribution of submerged bubbles caused by breaking wind waves clouds of bubbles are generated at the sea surface by breaking wind waves or by heavy rain rows of subsurface bubble clouds have been detected by a bottom mounted side scan sonar and are possibly formed by the effects of langmuir circulation a simple equation is devised to describe the effects of the turbulent diffusion of bubbles from the free surface bubble rise and dissolution and advection by langmuir circulation the equation is solved analytically using a series expansion in which advection is supposed small in comparison with diffusion the solution provides a quantitative measure of the principal effects produced by the circulation in particular the distortion of the bubble field and estimates of the advective flux a random walk numerical model in which changes occurring in individual bubbles are followed is tested against the analytical model in the range for which the latter is valid there is good agreement the numerical model is useful in extending the solutions to more complex cases which include a broad distribution of bubble sizes and to ranges in which the analytic solution is invalid the model is used to quantify the effect of the circulation on the acoustic scattering cross section of the bubble clouds and to explore differences between the conclusions of earlier models and observations by johnson cooke 1979 in the appendices an estimate is made of the depth to which bubbles can be carried by the vertical velocities observed below wind rows and this is found to agree reasonably well with the maximum depth to which bubbles are observed to penetrate estimates of mean vertical diffusion coefficients based on observations of bubbles are compared with some calculated solely from the advective flux in langmuir circulation the latter are as expected smaller than those representing the sum of all the contributions to the flux but are a significant fraction of the order of 0 2 0 4 a method of deriving the vertical diffusion coefficient from observations of the vertical distribution of the acoustic scattering cross section of bubbles appears not to be very sensitive to circulation and may provide estimates within about 25 of the actual values

normal and reverse unroofing sequences in syntectonic conglomerates as evidence of progressive basinward deformation when a new mountain belt is generated by tectonics the denudation of the mountain front may cause the development of alluvial fans at its base the retreat of the mountain front by denudation processes and a widening of the drainage network in the source area create adjacent alluvial fan conglomerates with an inverted vertical clast distribution this vertical clast distribution represents a normal unroofing sequence renewed uplift of a previous inverted vertical clast distribution can produce a reverse unroofing sequence if continued shortening occurs in the same area a rejuvenation of the source area and basin margin may produce a new generation of clasts from the source area and a partial or total reworking of previously deposited conglomerates to supply second generation clasts if this type of reworking process is repeated as fault uplift steps basinward several new inverted and stratigraphic vertical clast distributions may arise

helmolepis cyphognathus sp nov a new platysiagid actinopterygian from the lower triassic sulphur mountain formation british columbia canada a new species of stem actinopterygian helmolepis cyphognatus sp nov is reported from the lower triassic sulphur mountain formation of western canada probably smithian this taxon differs from the only other known early triassic platysiagid h gracilis from the lower triassic wordie creek formation of east greenland griesbachian in counts of branchiostegal rays shape of the maxilla shape and possibly counts of extrascapulars and the size ratio of major opercular bones in spite of their overall unfavorable preservation the numerous available specimens amend our knowledge of the little known genus helmolepis considerably it has become evident that the morphology of helmolepis cyphognatus sp nov comes closest to platysiagum minus middle triassic besano formation of central europe this study suggests placement of the two genera in the family platysiagidae investigation of this new species also shows certain features of the cheek and the caudal fin are more primitive than previously beli

more than one event in the late triassic mass extinction the recent hypothesis that mass extinctions are discrete phenomena that have occurred with great regularity during the history of life1 2 is testable in several ways two essential elements of the hypothesis are 1 that each extinction event represents a significant departure from normal or background rates of extinction and 2 that such mass extinction events are spaced equally in time the analyses of the cyclicity of mass extinctions so far have concentrated on the past 250 myr with the first event occuring at the permian triassic boundary 245 myr ago1 5 the second event followed 26 33 myr later1 6 in the late triassic here i present a detailed analysis of the fossil record of marine and non marine life during the late triassic which suggests that there were at least two phases of mass extinction during that time separated by 12 17 myr

size variation of brachiopods from the late permian through the middle triassic in south china evidence for the lilliput effect following the permian triassic extinction abstract whether body size reduction the lilliput effect occurred in the early triassic invertebrates remains a matter of debate here we investigate the size evolution of brachiopods spanning the late permian through the early to middle triassic based on 3316 brachiopod specimens from south china our results show that the maximum and median size among species decreased dramatically from the latest permian changhsingian to the earliest triassic griesbachian and then increased during the olenekian and anisian our data support the lilliput effect on brachiopods during the permian triassic mass extinction and its immediate aftermath size plots at species genus and family levels suggest that the earliest triassic size reduction resulted from two factors the preferential extinction of large brachiopod taxa size selective extinction and the size reductions in the survivors persistent increases in brachiopod size in the olenekian and anisian are likely the result of the extinction of small survivors the appearance of large sized species and the cope s rule that the new lineages tend to increase in body size over the early evolutionary time the cause of the earliest triassic size reduction of brachiopods might be environmental pressures such as global warming oceanic anoxia and increased water turbidity

mesozoic echinoid diversity in portugal investigating fossil record quality and environmental constraints on a regional scale several analyses of diversity through geological time use global synoptic databases and this practice often makes it difficult to distinguish true signals in changing diversity from regional scale sampling and or geological artefacts here we investigate how echinoid diversity changed through the mesozoic of the lusitanian basin in portugal based on a comprehensive revised database and seek to distinguish biological signal from geological or environmental constraints the observed diversity pattern is far from having a defined trend showing many fluctuations that appear to be linked with gaps in the geological record this study revealed that independently of the method used whether correlation tests or model fitting the diversity signal is not completely explained by the studied sampling proxies among the different proxies marine facies variation in combination with outcrop area best explains the palaeodiversity curve

dwarfism of irregular echinoids echinocorys from poland during the campanian maastrichtian boundary event abstract the echinoid genus echinocorys is one of the dominant irregular echinoid in the cretaceous of poland our analysis of the body size trends of these echinoids shows that they underwent dwarfism in the early maastrichtian the reduction in body size in these echinoids was likely an ecological response to the major climate perturbations connected with the campanian maastrichtian boundary event cmbe that was characterized by a long lasting negative carbon isotope excursion and cooling this is consistent with the fact that food limitations and cold temperatures are among the major factors decreasing growth rates in modern echinoids so far in the case of echinoids the so called lilliput effect has been only recognized in the early danian early paleogene heart urchins atelostomata thus our study shows that the reduction in the body size in echinoids was a more common biotic response to environmental stress than previously thought

global analyses of brachiopod faunas through the ordovician and silurian transition reducing the role of the lazarus effect global analyses of 88 families and 284 genera of brachiopods from middle ashgill late ordovician to early middle rhuddanian early silurian indicate that 18 6 and 12 5 of families and 51 0 and 41 3 of genera were eliminated in the first and second phases of the end ordovician mass extinction respectively with the total loss of 28 4 of families and 69 0 of genera in the crisis new investigation demonstrates that brachiopods at both generic and familial levels suffered greater during the first phase than during the second phase four groups victims relicts survivors and new arrivals are distinguished by their stratigraphical ranges generic survivors occurring in the kosov province during the hirnantian can be split into three types with respect to their changing abundance increasing declining and lazarus taxa among the 88 genera that survived numerous declining genera occurred in the hirnantian 16 lazarus families and 18 lazarus genera are provisionally known and may be regarded

recovery from the end permian extinction event evidence from lilliput listracanthus abstract we report the reduction of dermal denticle size in the chondrichthyan listracanthus in the context of other in faunal changes observed in a lower triassic section near wapiti lake british columbia listracanthus is the first chondrichthyan to show this lilliput effect following the great end permian mass extinction in our attempt to collate diverse information from associated faunal assemblages and large macrofossil collections we interpret the change in denticle size in listracanthus as occurring at around the induan olenekian boundary the relatively small change in denticle size can be interpreted in terms of the relative lack of effect of the biotic crisis on this chondrichthyan and maybe others or alternatively as the relatively much larger body size of listracanthus in comparison with other permo triassic boundary lilliput taxa it is speculated the lack of denticle enameloid and well developed vascularisation along with the moderate minimum in size below the induan olenekian boundary may indicate that listracanthus denticles are not necessarily external skeletal elements but possibly modified dermal denticles gill rakers of a large basking shark it is concluded that discovery of the early triassic species listracanthus pectenatus creates a ghost lineage of 30 ma and highlights the significance of discovering perishable remains of chondrichthyans in order to understand faunal changes across the permo triassic boundary

changes in size and growth rate of lilliput animals in the earliest triassic abstract marine invertebrate taxa that survived the late permian latest changhsingian mass extinction event are all much smaller than they were prior to the event an example of the lilliput effect new taxa that first appeared in the immediate extinction aftermath are also small compared to their size in younger strata the lilliput effect is a temporary phenomenon with most surviving taxa returning to pre extinction size in the first two conodont zones of the triassic in this study the growth rates of some of the early triassic lilliput animals estimated by growth line analysis were compared from different stratigraphic levels to determine how this variable fluctuated as body size returned to pre extinction values after the event specimens were collected from the mazzin and siusi members of the werfen formation in northern italy from facies deposited in a tropical mixed siliciclastic carbonate ramp setting measurements of the bivalves unionites and claraia the gastropod bellerophon and the brachiopod lingula were made in the field with subsequent growth line analysis conducted on well preserved specimens of lingula specimens collected from the basal triassic mazzin member were smaller than those from the younger siusi member growth line analysis indicates that the smaller mazzin member specimens had a greater number of more closely spaced growth lines than the larger siusi member specimens the small lilliput animals living in the immediate aftermath of the late permian event therefore suffered more interruptions to growth and had overall slower growth rates than larger individuals living in later recovery times frequent interruptions to growth and an overall slower growth rate in specimens from the hindeodus parvus and isarcicella isarcica zones of the mazzin member lower induan reflects suboptimal environmental conditions such as the frequency or severity of low oxygen episodes temperature extremes and or disruptions to primary productivity

bubble clouds and the dynamics of the upper ocean this is a review of turbulence in the upper ocean close to the sea surface particularly of the information that has been obtained from sonar observations of bubble clouds produced by breaking wind waves these clouds provide tracers of the turbulent motions and are important especially at high wind speeds in the process of air sea gas transfer the observations of bubble clouds are here related to other measurements of turbulence particularly to direct measurements of currents and temperatures in lakes or at sea and to laboratory studies some novel observations of bubble clouds and breaking waves their frequency and relation to langmuir circulation are presented there is now emerging a pattern of clues that point to the dominance of breaking surface gravity waves as a source of turbulence to a depth below the surface of 0 04 to 0 2 times the wavelength of the dominant breaking waves although the effect of swell has yet to be clarified the relative depth appears to increase with increasing values of w 1 c where w10 is the wind speed and c the phase speed of the dominant waves below this region the generation of turbulence may be dominated by shear stress or convection here turbulence is generally similar to that in the atmospheric boundary layer there are however coherent motions on the scale of the mixing layer that persist for periods of a few minutes to an hour or so to which the transport of a large part of the momentum and heat fluxes can be attributed and which strongly affect the dispersion of buoyant particles or bubbles these motions deserve special study to establish their contribution to heat and momentum transport and hence to determine if or when they should be specifically represented in models of the upper ocean devised for example to describe the dispersion of passive and non passive tracers or the air sea transfer of gases

the lower triassic sulphur mountain formation in the wapiti lake area lithostratigraphy conodont biostratigraphy and a new biozonation for the lower olenekian smithian earth science sector ess contribution 20080714 the sulphur mountain formation in the wapiti area is subdivided into the phroso meosin mountain new and vega members which collectively span much of the lower triassic the smithian conodont faunas are particularly well developed and form the basis of three partly new conodont zones and two new subzones the lachrymiformis zone meeki zone and mosheri zone with the last subdivided into the phryna and milleri subzones an informal lowermost smithian nepalensis interval is introduced although it has yet to be found in the area the phroso member is latest griesbachian dienerian and in its uppermost part smithian specifically the lachrymiformis and meeki zones these are shown to be equivalent to the euflemingites romunduri ammonoid zone the meosin mountain member is assigned to the meeki zone in its lower part and the phryna subzone of the mosheri zone in its upper part at least the upper part of the mosheri zone is equivalent to the anawasatchites tardus ammonoid zone the mackenzie dolomit

structure and variability of langmuir circulation during the surface waves processes program a cooperative multiplatform field experiment was conducted in the eastern north pacific during february and march of 1990 as part of the surface waves processes program swapp one of the experimental objectives was to investigate langmuir circulation so that its role in the evolution of the oceanic surface boundary layer could be better understood the concurrent use of different observational techniques ranging from simple surface drifters to complex doppler sonar systems resulted in new information about langmuir circulation structure and variability estimates of langmuir cell spacing indicated that a broad range of scales from about 2 to 200 m was excited during periods of strong surface forcing and that the energy containing scales evolved with time estimates of cell spacing based on doppler velocities from a surface scanning sonar directed crosswind showed this scale evolution but estimates based on backscattered intensity did not this was attributed to the fact that the intensity based estimates were only indirectly related to circulation strength the near surface convergent velocities from the sonar were used to form an objective quantitative measure of the temporal variations in langmuir circulation strength as expected the circulation strength increased dramatically during strong wind events however circulation strength and wind stress did not decrease simultaneously and langmuir circulation was detectable for up to a day after abrupt reductions in wind stress energy from the surface wave field which decayed more slowly than the wind was apparently responsible for maintaining the circulation the variation of circulation strength was found to be better related to u us than to u where u is the friction velocity is the wind stress and us is the surface wave stokes drift this scaling is consistent with wave current interaction theories of langmuir cell generation

dynamical processes of transfer at the sea surface abstract this review describes the dynamical processes of transport from and immediately below the sea surface particularly those which involve convergence and the separation of flow and which result in the renewal of surface water at horizontal scales ranging from millimeters to hundreds of meters turbulence at or near the sea surface derives from several processes breaking waves and the bubbles they may produce precipitation and spray langmuir circulation and thermal convection and turbulence which is internally generated by shear interest in the subject derives from the requirements to predict air sea fluxes of heat momentum and gases to develop climate models to interpret satellite images of the sea surface including those of ship wakes and to predict upper ocean structure including mixing layer depth in models of phytoplankton blooms and acoustic propagation the general effect of subsurface turbulence on the sea surface and the effects of surfactants is described and each process is discussed in turn laboratory experiments and theoretical studies have contributed particularly to the understanding of the interaction of vortices and turbulence with the surface and to the consequences of breaking waves they point to the development of instability in the flow ahead of steep waves carrying parasitic capillary waves which may contribute to the onset of flow separation on the leading face of the waves and the development of a rotor or roller below the wave crest shown most clearly in the pattern of streamlines in a frame of reference moving forward with the wave the conditions near the flow separation line on the wave surface ahead of the rotor may be similar to those produced by vortices approaching a free surface detailed observation of breaking waves at sea is lacking but some progress has been made using acoustics to detect the clouds of subsurface bubbles formed by the larger breakers and the depth to which they penetrate the possible importance of three dimensional effects in breaking waves is discussed and a conjectural sketch of the surface flow field and the surface separation and reattachment pattern following a plunging breaker is described recent observations show elevated levels of turbulence close to the sea surface the depth of the layer in which this occurs is shown to be consistent with information derived from sonar studies of the depth of bubble clouds the observed frequency of breaking waves and laboratory observations of breaking waves rain is known to knock down the sea reducing the frequency and intensity of breaking waves the precise mechanics of the phenomena are uncertain but an enhancement of near surface turbulence and the damping of short surface gravity waves has been observed in laboratory experiments langmuir circulation temperature ramps and convection all associated with coherent structures are processes which mix the upper ocean although their relative importance is unknown connections between studies with quite disparate motivations are found to help provide descriptions of the upper ocean processes and estimates of the time scale of surface renewal associated with each of the processes identified many quantities being transferred across the sea surface appear to be transported by dynamical processes of scale much smaller than that of the dominant surface waves although their subsequent diffusion in the mixing layer may be strongly influenced by the larger scale processes further careful measurements in the laboratory and at sea are required to quantify the fluxes associated with the processes and to relate them to external parameters such as wind speed

introduction to the special issue commemorating the 30th anniversary of the royal tyrrell museum of palaeontology with a summary of the museum s early history and its research contributions located just west of drumheller in southern alberta canada the royal tyrrell museum of palaeontology rtmp is nestled among outcrops of the upper cretaceous horseshoe canyon formation exposed along the red deer river valley fig 1 since it officially opened on 25 september 19851 the museum has become one of alberta s must see tourist attractions a significant contributor to the local economy and earned an international reputation for the quality of its palaeontological collections and the research conducted by its scientists the rtmp is unique within canada in being the only government supported museum dedicated to palaeontology and it is one of the few such institutions in the world fig 1 the royal tyrrell museum of palaeontology a front of museum and main entrance circa 2010 looking westwards and with horizontal beds of the upper cretaceous horseshoe canyon formation exposed in the walls of the red deer river valley in the distance b aerial photograph oblique angle and looking to the north northeast the museum sits on top of the number 7 coal seam sensu gibson 1977 and at the base of the horsethief member of the horseshoe canyon formation d a eberth pers comm 2015 that stratigraphic position correlates with an age of about 71 5 ma i e late campanian and lies within the upper part of the edmontosaurus regalis pachyrhinosaurus canadensis dinosaur assemblage zone see eberth et al 2013 fig 6 c the iconic running theropod logo that until recently graced the exterior of the museum below a life sized tyrannosaurid sculpture by brian cooley one of many such sculptures by cooley that have been featured at the museum since its opening in 1985 and with the education wing opened in 2003 as the atco tyrrell learning centre in the background d the cretaceous alberta life sized diorama opened in 2007 an example of a rtmp exhibit that relies heavily on discoveries and interpretations by museum researchers in this case work done in the albertosaurus bonebed and at other localities throughout the horseshoe canyon formation all photographs courtesy of the royal tyrrell museum of palaeontology this special issue of the canadian journal of earth sciences presents a collection of papers commemorating the rtmp s 30th or pearl anniversary our rationale for doing a 30th anniversary volume was two fold first it is an opportunity to showcase the breadth of research conducted by current and former museum scientists as well as by some colleagues having a history of collaboration with the rtmp the 13 invited papers included in this volume are a mix of review and original research papers all thematically focused on the geology and palaeontology of alberta to varying degrees each contribution is the result of work supported by the rtmp and relies on specimens housed in the museum s collections second the 30th anniversary is an opportunity to reflect on the rtmp s history and its research program as is typical for most institutions the rtmp has done little to formally document its own history this year likely will be the last major milestone for which the original generation of museum staff are still working and available to share their recollections about the museum fieldwork and research already deaths and departures have winnowed away part of the original

early triassic terrestrial tetrapod fauna a review abstract the permian triassic mass extinction ptme ca 252 mya was one of the most severe biotic crises of the phanerozoic eliminating 90 of marine and terrestrial species this was followed by a long period of recovery in the early and middle triassic which revolutionised the structure of both marine and terrestrial ecosystems triggering the new ecosystem structure of the mesozoic and cenozoic entire new clades emerged after the mass extinction including decapods and marine reptiles in the oceans and new tetrapods on land in both marine and terrestrial ecosystems the recovery is interpreted as stepwise and slow from a combination of continuing environmental perturbations and complex multilevel interaction between species in the new environments as ecosystems reconstructed themselves here we present a review of early triassic terrestrial tetrapod faunas geological formations and outcrops around the world and provide a semi quantitative analysis of a data set of early triassic terrestrial tetrapods we identify a marked regionalisation of early triassic terrestrial tetrapods with faunas varying in both taxonomic composition and relative abundance according to palaeolatitudinal belt we reject the alleged uniformity of faunas around pangaea suggested in the literature as a result of the hot house climate in addition we can restrict the tetrapod gap of terrestrial life in the early triassic to palaeolatitudes between 15 n and about 31 s in contrast to the earlier suggestion of total absence of tetrapod taxa between 30 n and 40 s there was fairly strong provincialism following the ptme according to cluster analysis of a taxon presence matrix entirely consistent with early triassic palaeobiogeography unexpectedly the overall pattern for early triassic terrestrial tetrapod faunas largely reflects that of the late permian suggesting that the recovery faunas in the early triassic retained some kind of imprint of tetrapod distributions according to palaeogeography and palaeoclimate despite the near total extinction of life through the ptme

tension over equitable allocation of water estimating renewable groundwater resources beneath the west bank and israel competition for water resources between palestine and israel is an ongoing cause of tension the western aquifer basin forms a major part of the complex largely karst limestone system of the west bank mountain aquifer the aquifer crops out and is recharged solely in the semi arid uplands of the west bank and groundwater flows west beneath israel to discharge at the yarqon and nahal taninim springs near the mediterranean coast annual recharge to the aquifer is not easy to quantify but lies within the range 270 106 to 455 106 m3 a 1 and current uncertainties do not support definition of a single value of long term average recharge the resource is heavily exploited and abstraction is directly controlled and apportioned between israel and the west bank by israel the key to equitable apportionment is the determination of the long term average recharge to the basin which also requires definition of the eastern boundary of the basin to confirm the recharge area calculations include empirical formulae and process based models that are likely to constrain the best estimate provided that there is appropriate ongoing monitoring improved understanding can then be fed back into the model

lazarus taxa and fossil abundance at times of biotic crisis mass extinctions are often followed by intervals in which taxa disappear from the fossil record only to reappear again later this lazarus effect is often attributed to a poor quality fossil record or migration to refuges testing these alternatives with examples from the end permian and late triassic extinctions reveals that there is no link with the abundance of fossiliferous sites and the proportion of lazarus taxa nor are missing taxa encountered in potential refuges therefore the abundance of lazarus taxa in the aftermath of these extinctions is probably a reflection of the extreme rarity of organisms at this time

evolutionary dynamics of the permian triassic foraminifer size evidence for lilliput effect in the end permian mass extinction and its aftermath abstract there is growing evidence of the lilliput effect in the end permian mass extinction and its aftermath however very little has been published on assessing the lilliput effect on protozoans in the early triassic based on quantitative analysis of a great quantity of samples from outcrop sections this study investigates foraminiferal test size variations through the changhsingian to the olenekian based on fossil records from three outcrop sections in south china the sharp reduction in foraminifer sizes coincides with the first or main episode of the end permian mass extinction foraminifers remained small in sizes in the early induan their body sizes increased slowly in the late induan to olenekian but never recovered to the pre extinction test size levels the lilliput effect on foraminifera in the aftermath of the end permian crisis is indicated by the extinction of large taxa decrease in size for surviving taxa and rise of small sized new forms physiological reactions of various foraminifer groups reveal that several defaunation events such as anoxia ocean acidification and global warming that prevailed through the permian triassic interval may be responsible for both the end permian crisis and the lilliput effect

fishes from the lower triassic portion of the sulphur mountain formation in alberta canada geological context and taxonomic composition the sulphur mountain formation in alberta canada comprises shales siltstones and limestones laid down on the continental shelf and shoreline along the western margin of the north american craton during the early and middle triassic at least 13 taxa of fossil marine fishes have been found at a number of triassic localities along the front ranges and foothills in alberta common taxa boreosomus birgeria bobasatrania australosomus saurichthys parasemionotids and coelacanths found at localities in alberta are similar to those found at the classic lower and middle triassic localities near wapiti lake british columbia and in east greenland spitzbergen madagascar and china the occurrence of lower triassic fishes in western alberta shows that this fauna was widespread occurring over at least 1000 km of shoreline and that ecological and environmental factors were similar along the western edge of the panthalassic ocean during the early triassic

lilliput effect in freshwater ostracods during the permian triassic extinction abstract the lilliput effect following the permian triassic mass extinction and its aftermath has been documented in a variety of marine animal groups but it is less known in terrestrial and freshwater invertebrates here we present new investigations of the size variations of terrestrial ostracods of the genus darwinula based on fossil records from a permian triassic section on the northern limb of the dalongkou anticline section in northwest china quantitative analyses reveal that ostracod test sizes decreased sharply through the terrestrial permian triassic mass extinction interval the lilliput effect in terrestrial ostracods is characterized by the extinction of large taxa and the rise of small sized and elongate new forms coupled with the dramatic loss of conchostracans charophytes and the blooming of lycopod spores the size decrease in terrestrial ostracods following the biotic crisis through the permian triassic interval was probably triggered by several interacting events including global warming anoxia and enhanced sediment input following acid rain and wildfire

the cretaceous tertiary biotic transition mass extinctions are recognized through the study of fossil groups across event horizons and from analyses of long term trends in taxonomic richness and diversity both approaches have inherent flaws and data that once seemed reliable can be readily superseded by the discovery of new fossils and or the application of new analytical techniques herein the current state of the cretaceous tertiary k t biostratigraphical record is reviewed for most major fossil clades including calcareous nannoplankton dinoflagellates diatoms radiolaria foraminifera ostracodes scleractinian corals bryozoans brachio pods molluscs echinoderms fish amphibians reptiles and terrestrial plants macrofossils and palynomorphs these reviews take account of possible biasing factors in the fossil record in order to extract the most comprehensive picture of the k t biotic crisis available results suggest that many faunal and floral groups ostracodes bryozoa ammonite cephalopods bivalves archosaurs were in decline throughout the latest maastrichtian while others diatoms radiolaria benthic foraminifera brachiopods gastropods fish amphibians lepidosaurs terrestrial plants passed through the k t event horizon with only minor taxonomic richness and or diversity changes a few microfossil groups calcareous nannoplankton dinoflagellates planktonic foraminifera did experience a turnover of varying magnitudes in the latest maastrichtian earliest danian however many of these turnovers along with changes in ecological dominance patterns among benthic foraminifera began in the latest maastrichtian improved taxonomic estimates of the overall pattern and magnitude of the k t extinction event must await the development of more reliable systematic and phylogenetic data for all upper cretaceous clades

the smooth brachiopods of the mediterranean jurassic refugees or invaders the jurassic brachiopod fauna of the alpine mediterranean region is dominated by smooth rhynchonellids and spiriferinids and sulcate or perforate terebratulids in contrast to the typical coarsely ribbed brachiopods of the contemporaneous european and african epicontinental areas the best studied example of the mediterranean brachiopod province is the pliensbachian fauna of the bakony mountains hungary there the five most abundant genera are all smooth linguithyris securithyris apringia bakonyithyris pisirhynchia these smooth genera represent different morphological types sulcate axiniform uniplicate phylogenetically related forms are known from several evolutionary lineages of discontinuous record ranging from the triassic to the recent the triassic jurassic and the neogene recent parts of these evolutionary lineages are represented by several genera while in the late cretaceous paleogene interval they seemingly disappear at least they have no record the recent relatives of the above pliensbachian genera live mostly in the deep sea three are shallow bathyal 200 400 m three deep bathyal 800 1200 m and three abyssal 2000 4500 m the abyssal genera occur mainly in the east pacific the geographical distribution of the bathyal genera shows peculiar features they are more or less confined to the western sides of the great ocean basins west pacific west indian ocean caribbean region and they are thalassobathyal i e they are living on submarine plateaus seamounts or island aprons and not on the continental slopes this pattern extrapolated to the past shows good analogy with the jurassic palaeogeographical model developed for the western part of the tethys ocean it is hypothesized that smooth mainly sulcate articulate brachiopods flourished in the bathyal or even abyssal zones during the palaeozoic they were not refugees but formed well adapted communities this stable conservative fauna may have survived the crises manifested in the shelf seas and in cases of appropriate palaeogeographical situations may have implanted its descendants to the shallow bathyal or even sublittoral regions of the western margins of the ocean basins the mediterranean microcontinent system at the western part of the jurassic tethys might have been such an invaded region correlation between plate tectonic changes of ocean continent configurations the presence of ocean basins closed on the west and the occurrence of smooth articulate brachiopod groups in shallow bathyal to sublittoral settings collectively suggest that the deep water forms invaded the shallow environments of the western tethys in early mesozoic times and the w pacific and w indian oceans in the neogene they stayed in the deep sea reservoir when a circum equatorial ocean existed in the late mesozoic

the timing and pattern of biotic recovery following the end permian mass extinction the aftermath of the great end permian period mass extinction 252 myr ago shows how life can recover from the loss of 90 species globally the crisis was triggered by a number of physical environmental shocks global warming acid rain ocean acidification and ocean anoxia and some of these were repeated over the next 5 6 myr ammonoids and some other groups diversified rapidly within 1 3 myr but extinctions continued through the early triassic period triassic ecosystems were rebuilt stepwise from low to high trophic levels through the early to middle triassic and a stable complex ecosystem did not re emerge until the beginning of the middle triassic 8 9 myr after the crisis a positive aspect of the recovery was the emergence of entirely new groups such as marine reptiles and decapod crustaceans as well as new tetrapods on land including eventually dinosaurs the stepwise recovery of life in the triassic could have been delayed either by biotic drivers complex multispecies interactions or physical perturbations or a combination of both this is an example of the wider debate about the relative roles of intrinsic and extrinsic drivers of large scale evolution from a much more devastated planet and biota than the others with only some 10 of species surviving the epme was much harsher than the other mass extinctions during which global species diversity reduced to only about 50 of the pre extinction total 1 2 24 26 this means that the triassic recovery has two profound implications first it may show qualitative as well as quantitative differences from the other post extinction recoveries and second it can act as an exemplar of what to expect at its most extreme when global biodiversity is pushed to the brink there are obvious implications for current concerns about biodiversity loss and recovery resulting from human impacts 27 28 in the past ten years attention has focused on the sedimentary successions in south china these are enormously laterally extensive with some formations extending more than 2 000 km from the zhejiang to yunnan provinces the huge exposures length of the sections and improving dating open up the opportunity to explore physical environmental and biotic changes through the extinction and recovery times in varied marine habitats and compare these with patterns elsewhere in the world fig 1 a fine scale forensic analysis of this extraordinary time in earth s history now becomes possible the end permian mass extinction the epme killed 80 96 of marine animal species and 70 of terrestrial vertebrate species

early triassic early olenekian life in the interior of east gondwana mixed marine terrestrial biota from the kockatea shale western australia abstract a new terrestrial marine assemblage from the lower beds of a thin outcrop section of the kockatea shale in the northern perth basin western australia contains a range of fossil groups most of which are rare or poorly known from the lower triassic of the region to date the collection includes spinose acritarchs organic cemented agglutinated foraminifera lingulids minute bivalves and gastropods ammonoids spinicaudatans insects austriocaridid crustaceans actinopterygians a temnospondyl like mandible plant remains and spores and pollen of these groups the insects crustaceans and macroplant remains are recorded for the first time from this unit palynomorphs permit correlation to nearby sections where conodonts indicate an early olenekian smithian age the locality likely represents the margin of an early triassic shallow interior sea with variable estuarine like water conditions at the southwestern end of an elongate embayment within the east gondwana interior rift sag system preserved along the western australian margin monospecific spinose acritarch assemblages intertwined with amorphous organic matter may represent phytoplankton blooms that accumulated as mats and suggest potentially eutrophic surface waters the assemblage represents a mixure of marine and terrestrial taxa suggesting variations in water conditions or that fresh brackish water and terrestrial organisms were transported from adjacent biotopes some of the lower dark shaly beds are dominated by spinicaudatans likely indicating periods when the depositional water body was ephemeral isolated or subjected to other difficult environmental conditions the biota of the kockatea shale is insufficiently known to estimate biotic diversity and relationships of individual taxa to their permian progenitors and triassic successors but provides a glimpse into a coastal zone from the interior of eastern gondwana specialist collecting is needed to clarify the taxonomy of many groups and comparisons to other lower triassic sites are required to provide insights into the pattern of biotic decline and recovery at the end permian crisis

hydrologic issues in arid unsaturated systems and implications for contaminant transport analysis of unsaturated flow and transport in arid regions is important not only in water resource evaluation but in contaminant transport as well partic ularly in siting waste disposal facilities and in remediat ing contaminated sites the water fluxes under consid eration have a magnitude close to the errors inherent in measuring or in calculating these water fluxes which makes it difficult to resolve basic issues such as direction and rate of water movement and controls on unsaturated flow the purpose of this paper is to review these issues on the basis of unsaturated zone studies in arid settings because individual techniques for estimating water fluxes in the unsaturated zone have limitations a variety of physical measurements and environmental tracers should be used to provide multiple independent lines of evidence to quantify flow and transport in arid regions the direction and rate of water flow are affected not only by hydraulic head gradients but also by temperature and air pressure gradients the similarity of water fluxes in a variety of settings in the southwestern united states indicates that vegetative cover may be one of the pri mary controls on the magnitude of water flow in the unsaturated zone however our understanding of the role of plants is limited most unsaturated flow in arid systems is focused beneath topographic depressions and diffuse flow is limited thick unsaturated sections and low water fluxes typical of many arid regions result in preservation of paleoclimatic variations in water flux and suggest that deep vadose zones may be out of equilib rium with current climate whereas water movement along preferred pathways is common in humid sites field studies that demonstrate preferential flow are restricted mostly to fractured rocks and root zones in arid regions results of field studies of preferential flow in humid sites generally restricted to the upper 1 2 m because of shallow water tables cannot be applied readily to thick vadose zones in arid regions

early triassic gulliver gastropods spatio temporal distribution and significance for biotic recovery after the end permian mass extinction a reduction in body size lilliput effect has been repeatedly proposed for many marine organisms in the aftermath of the permian triassic pt mass extinction specifically reduced maximum sizes of benthic marine invertebrates have been proposed for the entire early triassic this concept was originally based on observations on early triassic gastropods from the western usa basin and the dolomites n italy and it stimulated subsequent studies on other taxonomic groups however only a few studies have tested the validity of the lilliput effect in gastropods to determine whether the paucity of large sized gastropods is a genuine signal or the result of a poor fossil record and insufficient sampling in combination with a review of the literature we document numerous new abundant large sized gastropods from the griesbachian outcrops of greenland and from the smithian early spathian interval in the southwestern usa we show that large sized gulliver gastropods i were present soon after the pt mass extinction ii occurred in various basins sedimentary facies and environmental contexts from shallow to deeper settings and iii belong to diverse higher rank taxa focusing on the western usa basin we investigate areas from which microgastropod shell beds were previously presented as being typical however we show that gulliver gastropods do occur in the very same areas insufficient sampling effort is probably the main reason for the rarity of reports of large early triassic gastropods which is supported by preliminary rarefaction based simulations finally it appears that the recently documented middle to late smithian climate shifts and the severe end smithian extinction of nekto pelagic faunas did not reduce maximum shell sizes of gastropods

water table fluctuation and recharge in semi arid climate some results of the hapex sahel hydrodynamic survey niger groundwater level measurements taken over a 4 year period from an extensive network of wells and boreholes within the hapex sahel hydrologic atmospheric pilot experiment in the sahel degree square south niger together with existing data have provided an insight into infiltration and recharge processes taking place in the porous phreatic aquifer of the continental terminal formation despite high spatial and temporal variability of aquifer response to rainfall rises of between 0 and 9 m are recorded a pattern of recharge can be recognised aquifer responses vary from site to site but the type of response at any single point tends to be consistent from year to year recharge is dominated by infiltration from temporary drainage networks pools and streams and aquifer response depends to a large extent on aquifer hydraulic characteristics and distance from the nearest infiltrating zone in many wells for which data extending back to 1987 is available water levels show a consistent year by year rise this is interpreted as a process of aquifer recovery following the severe drought of the 1970s and early 1980s though part may also be attributable to changing patterns of land management e g woodland clearance initial estimates of regional recharge are from 50 60 mm year 1 or in other words about 10 of annual rainfall the figure is supported by other methods of investigation hydrochemical analyses water budgets of pools

recurrent biotic rebounds during the early triassic biostratigraphy and temporal size variation of conodonts from the nanpanjiang basin south china eleven conodont zones are established for the lower triassic of the motianling section in the nanpanjiang basin south china detailed size measurements on 2244 p1 conodont elements demonstrate dynamic size variation patterns during the early triassic that are calibrated to the early triassic timescale and conodont zonation correlation of conodont size variation with various environmental indicators shows that these size changes are primarily controlled by rapidly changing and episodic environmental conditions and ecological recovery in the aftermath of the end permian mass extinction decreasing size trends occur in the early griesbachian late griesbachian and at the smithian spathian boundary episodes of size increase rebounds occur in the middle griesbachian induan olenekian boundary and middle late spathian the observed temporal size variations indicate that conodont animals were significantly affected by rapidly changing environmental conditions mainly temperature and redox conditions during the early triassic and recurrent size increases rebounds occurred during periods of environmental and climatic amelioration climatic cooling and oxygenation demonstrating a complicated recovery history of marine ecosystems in the aftermath of the largest phanerozoic biotic crisis supplementary material data for all species are available at https doi org 10 6084 m9 figshare c 4528616