the structure biological activity and biogeochemistry of cryoconite aggregates upon an arctic valley glacier longyearbreen svalbard glacier surfaces support unique microbial food webs dominated by organic and inorganic debris called cryoconite observations from longyearbreen spitsbergen show how these aggregate particles can develop an internal structure following the cementation of mineral grains mostly quartz and dolomite by filamentous microorganisms measurements of carbon and dissolved o2 show that these microorganisms mostly cyanobacteria promote significant rates of photosynthesis average 17 gc g 1 d 1 which assist aggregate growth by increasing the biomass and producing glue like extracellular polymeric substances the primary production takes place not only upon the surface of the aggregates but also just beneath due to the translucence of the quartz particles however since total photosynthesis is matched by respiration average 19 gc g 1 d 1 primary production does not contribute directly to cryoconite accumulation upon the glacier surface the microorganisms therefore influence the surface albedo most by cementing dark particles and organic debris together rather than simply growing over it time lapse photographs show that cryoconite is likely to reside upon the glacier for years as a result of this aggregation these observations therefore show that a better understanding of the relationship between supraglacial debris and ablation upon glaciers requires an appreciation of the biological processes that take place during summer

high resolution monitoring reveals dissolved oxygen dynamics in an antarctic cryoconite hole this study presents the first high resolution dataset of dissolved oxygen do measurements in an ice lidded cryoconite hole on canada glacier mcmurdo dry valleys antarctica fibre optic do minisensors were installed in a cryoconite hole prior to seasonal internal melting and hydrological connection to the subsurface drainage system oxygen air saturation in the cryoconite hole typically ranged from 50 to 80 in broad agreement with previous single measurements indicating net respiration r this is consistent with results of simple incubation experiments performed in the field simultaneous time series for electrical conductivity water temperature and do over the four week study period provide information regarding the connectivity of cryoconite holes with the near surface drainage system the main driver of the observed variations in do is likely to be periodic melt freeze cycles we conclude that automated sensing techniques such as those described here when used in conjunction with physical measurements have great potential for high resolution monitoring of the factors that perturb biogeochemical processes in cryospheric surface aquatic ecosystems

biological processes on glacier and ice sheet surfaces glacial ice covers around 10 of the earth s continents a review of the literature suggests that microbes living on glaciers and ice sheets are an integral part of both the glacial environment and the earth s ecosystem

early neoproterozoic origin of the metazoan clade recorded in carbonate rock texture early neoproterozoic reefs older than 779 younger than 1083 ma contain a carbonate rock texture already familiar from sponge rich phanerozoic limestones characterized by authigenic ca carbonate and irregular secondary voids containing internal sediment poly mud fabric in holocene sediment this texture develops by calcification of degrading extra cellular collagenous matrix ecm of siliceous sponges ecm calcification of siliceous sponges is evident throughout the phanerozoic and the related polymud fabric is a diagnostic petrographic feature of phanerozoic sponge rich carbonate mudmounds the authigenic ca carbonate of polymuds is interpreted to result from connective tissue calcification just beneath the seafloor that in a kind of taphonomic race takes place at the same time as tissue oxidation and associated void formation it is intriguing that ecm is a fundamental character of the metazoan clade and so the presence in early neoproterozoic rocks of a texture directly associated with it implies the existence of metazoan grade organisms at that time this observation pushes back the earliest geological evidence for animals by about 200 m y the timing corroborates results of an integrated phylochronology and supports the concept of a biosphere that persisted through the snowball earth interval

nitrogen fixation on arctic glaciers svalbard telling j anesio a m tranter m irvine fynn t hodson a butler c wadham j 2011 nitrogen fixation on arctic glaciers svalbard journal of geophysical research biogeosciences 116 article number g03039

enigmatic chambered structures in cryogenian reefs the oldest sponge grade organisms abstract previously undescribed chambered structures are common and widespread in the cryogenian post sturtian glacial carbonates of the oodnaminta reef complex adelaide geosyncline south australia the rasthof berg aukas formation namibia and the gauss formation namibia these carbonate structures have millimetre to centimetre scale chambers separated by well defined and generally thin micritic walls chamber walls now consist of dolomite but were probably originally aragonitic the chambers may have a lobate polygonal or dendritic morphology and are often further divided into smaller chambers chambered structures occur as reefal growth frameworks as cavity fillings in neptunean dykes and growth cavities and as intercolumnar material within stromatolite frameworks in the oodnaminta reef complex these structures are only present in the sub photic deep water framework these structures probably represent the calcified remains of an organism or community of organisms that was globally distributed and widespread for a significant time period following the sturtian glaciation no precisely analogous structures have been previously described from modern or ancient settings but the complexity and degree of organization suggests a significant evolutionary advance over older proterozoic fossils the closest morphological analogues for the structures are a some types of reef dwelling sponges and b some complex microbialites from archaean and paleoproterozoic carbonates the structures lack spicules and ostia found in sponges ruling out a true poriferan origin however it is plausible that they are proto sponges sponge grade organisms or complex microbial precursors to sponge grade organisms whatever their affinity we suggest these structures record a significant evolutionary event on the path towards organic complexity

the mass area relationship within cryoconite holes and its implications for primary production cook j hodson a telling j anesio a irvine fynn t bellas c 2010 the mass area relationship within cryoconite holes and its implications for primary production annals of glaciology 51 56 106 110

the cryoconite ecosystem on the greenland ice sheet this paper presents an assessment of biological activity associated with ice surface debris cryoconite at the ice sheet scale estimates of the mass distribution of cryoconite over the greenland ice sheet gis and the biological activity associated with it are presented and then coupled with a surface mass balance model to estimate total carbon fluxes due to respiration and photosynthesis we find an average loading of 66 g m 2 at kangerlussuaq southwest greenland which compares well with recent estimates from kronprins christians land 17 440 g m 2 boggild and others 2010 in northeast greenland we also report a significant microbial biomass in cryoconite at both these places 10 3 10 4 cells mg 1 and carbon fluxes of the order of 1 3 m mcg 1 d 1 for both respiration and photosynthesis the modelling indicates that total respiration and photosynthesis fluxes are likely to be 10 1 10 2 gg c a 1 and thus far from trivial however estimation of the net ecosystem impact across the entire ice sheet on atmospheric co2 concentrations is problematic because photosynthesis rates were almost certainly low during our field campaign therefore like its water balance the carbon balance of the gis is now known to be important but its accurate quantification will remain elusive until more data are forthcoming

giant subtidal stromatolites forming in normal salinity waters we report here the discovery of giant lithified subtidal columnar stromatolites 2 m high growing in 7 8 m of clear oceanic water in current swept channels between the exuma islands on the eastern bahama bank they grow by trapping ooid and pelletal carbonate sand and synsedimentary precipitation of carbonate cement within a field of giant megaripples the discovery is important to geologists and biologists because similar organo sedimentary structures built by a combination of cementation and the trapping of sediment by microbes were the dominant fossil types during the precambrian stromatolites are thought to have been responsible for the production of free oxygen and thus the evolution of animal life1 2 until the discovery of small lithified subtidal columnar stromatolites in the bahamas3 the only subtidal marine examples known to be living while undergoing lithification were in the hypersaline waters of hamelin pool at shark bay western australia4 7 shark bay stromatolites range from intertidal to the shallow subtidal with the larger columns reaching 1 m in height the shark bay stromatolites have strongly influenced geological interpretation by analogy many ancient stromatolites have been considered to have grown in intertidal and or hypersaline conditions8 although hypersalinity was not a necessity for growth during the precambrian because grazing metazoan life had not then evolved

impacts of a mesoscale eddy pair on internal solitary waves in the northern south china sea revealed by mooring array observations abstractboth internal solitary waves isws and mesoscale eddies are ubiquitous in the northern south china sea scs in this study the authors examine the impacts of mesoscale eddies on the isws transiting the northern scs deep basin that evolve from the steepening internal tide generated in the luzon strait using in situ data collected from a specifically designed mooring array from november 2013 to january 2014 an energetic mesoscale eddy pair consisting of one anticyclonic eddy ae and one cyclonic eddy ce propagated across the mooring array observations revealed that the amplitude propagation direction and speed of the transbasin isws were significantly modulated by the eddy pair when the moorings were covered by the southern portion of the ae the isw amplitudes decreased by as much as 67 because of the thermocline deepening along the wave direction and the energy divergence along the wave front when the moorings were covered by the northern portions of both eddies the amplitude of is

remote sensing evidence for baroclinic tide origin of internal solitary waves in the northeastern south china sea 1 evidence for baroclinic tide origin of internal solitary waves isws in the northeastern south china sea is presented based on 116 internal wave packets observed in satellite images from 1995 to 2001 these wave packets can be divided into two types a single wave isw packet containing only one isw with without an oscillating tail and a multiple wave isw packet composed of a group of rank ordered isws all of the 22 single wave isw packets occur in the deep water zone it is suggested that the isws instead of being generated by the lee wave mechanism are developed by nonlinear steepening of the baroclinic tides which are produced by the strong tidal currents flowing over a ridge in luzon strait this suggestion is verified by an ers 2 sar image which records such an evolution process from a baroclinic tide to a single isw in its spatial domain

carbon fluxes through bacterial communities on glacier surfaces there is very little information about the activity of microbial communities on the surface of glaciers though there is an increasing body of evidence to show that they strongly influence the biogeochemistry of these habitats we measured bacterial abundance and production in cryoconite holes on arctic antarctic and alpine glaciers in order to estimate the role of heterotrophic bacteria within the carbon budget of glacial ecosystems our results demonstrate an active bacterial community on the surface of glaciers with doubling times that vary from a few hours to hundreds of days depending on the glacier and position water or sediments within the cryoconite hole however bacterial production is only 2 3 of the published literature values of community respiration from similar habitats indicating that other types of microbes e g eukaryotic organisms may also play a role in the c cycle of glaciers we estimate that only up to 7 of the organic c in cryoconite sediments is utilized by the heterotrophic bacterial community annually suggesting that the surface of glaciers can accumulate organic carbon and that this c may be important for biogeochemical activity downstream to adjacent ecosystems

role of mesoscale eddies in modulating the semidiurnal internal tide observation results in the northern south china sea abstractthe role of mesoscale eddies in modulating the semidiurnal internal tide sit in the northern south china sea scs is examined using the data from a cross shaped mooring array from novem

nonlinear evolution of ocean internal solitons propagating along an inhomogeneous thermocline measurements of the upper ocean thermal structure show that on the continental shelves the thermocline depth may shoal or deepen generally depending on the bottom topography thermocline shoaling and deepening cause changes in the phase speeds of internal waves as described by linear wave theories on the other hand the ocean area where internal waves have variable phase speeds may be treated as a dynamically inhomogeneous medium in this case theories of nonlinear dispersive wave propagation in inhomogeneous media developed by tappert and zabusky 1971 may stand we used these theories to analyze the evolution of ocean internal solitary waves passing over a seamount in the gulf of aden the results indicate that a surprisingly sharp recess of an internal solitary wave packet imaged by the space shuttle discovery is a signature of spatial phase delay caused by thermocline shoaling over the seamount soliton fission due to thermocline shoaling was also observed in the imagery the observed number of transmitted solitons over the seamount agrees with theoretical predictions relative soliton amplitudes measured from the imagery also agree qualitatively with predictions

microbial habitat dynamics and ablation control on the ward hunt ice shelf the ward hunt ice shelf 83 02 n 74 00 w is an 40 m thick ice feature that occupies a large embayment along canada s northernmost coast sediments cover 10 of its surface and provide a habitat for diverse microbial communities these assemblages form an organo sedimentary matrix microbial mat composed of cold tolerant cyanobacteria and several other types of organisms we investigated the environmental properties temperature irradiance conductivity and nutrient concentration of the microbial mat habitat and the effect of the microbial mats on the surface topography of the ice shelf the low albedo of microbial mats relative to the surrounding snow and ice encouraged meltwater production thereby extending the growth season to 61 days despite only 52 days with mean temperatures above 0 c we found large excursions in salinity near the microbial mat during freeze up and melt and 54 of all ponds sampled had conductivity profiles indicating stratification nutrient concentrations within the microbial mats were up to two orders of magnitude higher than those found in the water column which underscores the differences between the microbial mat microenvironment and the overall bulk properties of the cryo ecosystem the average ice surface ablation in the microbial mat rich study site was 1 22 m year 1 two times higher than values measured in areas of the ice shelf where mats were less prevalent we demonstrate with topographic surveys that the microbial mats promote differential ablation and conclude that the cohesive microbial aggregates trap and stabilize sediment reduce albedo and thereby influence the surface morphology of the ice shelf copyright 2006 john wiley sons ltd

wave induced mixing in the upper ocean distribution and application to a global ocean circulation model 1 from the reynolds stress expression the wave induced vertical viscosity or diffusivity bv is defined which can be used as a parameter to estimate the strength of wave induced mixing in addition a parameter d5 is introduced to represent a wave induced mixing penetration depth the global distribution of bv averaged over the upper 20 m is calculated and its latitudinal transects in boreal summer and winter is discussed the results show that in summer the wave induced mixing is strong in the southern oceans south of 30 s and in winter it is strong in the north pacific and the north atlantic north of 30 n as well as in the southern oceans south of 40 s adding bv to the vertical diffusivity in a global ocean circulation model yields a temperature structure in the upper 100 m that is closer to the observed climatology than a model without the wave induced mixing

on the generation and evolution of nonlinear internal waves in the south china sea the nonhydrostatic regional ocean modeling system is applied to the nonlinear internal waves or solitons that are generated at the luzon ridge in the south china sea the luzon ridge near the batan islands is represented by an idealized ridge with a height of 2 6 km on a flat bottom model runs are performed for various ridge shapes and a symmetric tidal forcings the model is in the mixed tidal lee wave regime the barotropic tide over the ridge generates first mode waves through the internal tide release mechanism westward traveling solitons emerge from these first mode waves through nonlinear steepening in the internal tide release mechanism asymmetric tides with strong eastward currents can generate strong westward solitons the eastward current creates an elevation wave with a higher energy density west of the ridge and as soon as the current slackens the wave is released westward on its backslope strong solitons develop the energy density is further enhanced by nonlinearities such as differences in phase speeds and energy fluxes related to lee waves a modal and harmonic decomposition shows the generation of vertical modes and higher temporal harmonics and indicates significant wave wave interaction e g triads in the mixed tidal lee wave regime more energy is contained in the first mode compared to the higher modes hence linear internal tide beams are less well defined and strong solitons develop

extreme hydrochemical conditions in natural microcosms entombed within antarctic ice cryoconite holes are near vertical tubes that form in the surface of glaciers when solar heated debris melts into the ice those that form in the mcmurdo dry valleys of antarctica are distinctive in that they have ice lids and are closed to the atmosphere for periods of years to decades photoautotrophs and heterotrophs grow within this closed environment perturbing the poorly buffered water chemistry yet maintaining the potential for photosynthesis microbial excretion and decomposition of organic matter produces dissolved organic carbon doc dissolved inorganic carbon ratios of 1 2 much of the dissolved nitrogen pool 80 100 exists as dissolved organic nitrogen don the don doc ratio is 1 11 mol mol typical of organic particulate material at the earth s surface the combination of photoautotrophy heterotrophy and weak chemical buffering within these microcosms promotes values of ph pco2 o2 saturation and percentage total dissolved nitrogen as don that reach 10 99 10 7 6 atm 160 and 100 respectively which are a unique combination among the surface waters on earth these ice sealed cryoconite holes could be important analogues of refugia on snowball earth and other icy planets

theoretical expression for an ocean internal soliton synthetic aperture radar image and determination of the soliton characteristic half width this paper deals with the development of techniques for satellite synthetic aperture radar sar ocean image interpretation we derived a theoretical model of a radar image for a korteweg de vries type ocean internal soliton and validated the model using ocean internal wave signals taken from ers 1 sar and radarsat sar images the results indicate that the model perfectly simulates ocean internal soliton signatures with double sign variations of radar backscatter on the basis of the model we developed the curve fitting method and the peak to peak method for determining the internal soliton characteristic half widths which then were used to calculate the internal soliton amplitudes the test results indicate that ocean internal soliton amplitudes derived by the two methods agree with in situ data acquired on the portuguese continental shelf and in the south china sea with reasonable accuracy the role that wind fields play in ocean radar remote sensing was also analyzed finally the modulation ratio of ocean internal waves on radar images was quantitatively estimated

questioning the microbial origin of automicrite in ordovician calathid demosponge carbonate mounds calathid demosponge carbonate mounds are a feature of early to middle ordovician shallow marine carbonate depositional environments of tropical to subtropical palaeolatitudes these mounds contain an important amount of autochthonous non skeletal microcrystalline calcium carbonate automicrite conventionally considered microbial in origin here the automicrite of calathid demosponge carbonate mounds tarim basin north west china is broken down into five distinct fabrics an in situ peloidal spiculiferous fabric am 1 an in situ peloidal fabric am 2 an aphanitic microtubular fabric am 3 a minipeloidal fabric am 4 and a laminoid cerebroid fabric am 5 type am 1 occurs with am 2 being succeeded by an assemblage of am 3 and am 4 types am 4 and am 5 are separated by an erosional disconformity a good correlation of fluorescence and cathodoluminescence of automicrites indicates that induced and supported organomineralization produced automicrite probably via the permineralization of non living organic substrates adsorbing dissolved metal humate complexes using a spreadsheet with six parameters and 17 characters am 1 to am 4 turn out to be non microbial in origin instead these automicrites represent relics of calcified metazoan tissues such as siliceous sponges non spiculate sponges or the basal attachment structures of stalked invertebrates fabric am 5 is a microbial carbonate but is post mound in origin forming a drape within a reefal framework established by am 4 the five automicritic fabrics individually or as an assemblage are a common element of ordovician calathid demosponge carbonate mounds in general the reassessment of the origins of these automicritic fabrics holds consequences for understanding of the great ordovician biodiversification event in terms of community structure reef ecology and reef evolution episodically these fabrics are also present in other carbonate build ups stretching from the neoproterozoic over the entire phanerozoic eon the massive calcification of metazoan soft tissue am 1 to am 4 characterizes episodes and conditions of enhanced marine calcification and might be of value to refine secular trends of pco2 ca concentration and mg ca ratio at the scale of individual sedimentary basins

effects of kuroshio intrusions on nonlinear internal waves in the south china sea during winter 1 during winter the kuroshio tends to cross luzon strait penetrating the northeastern south china sea where it forms energetic mesoscale structures luzon strait is also a site where westward propagating large amplitude internal waves are generated we describe observations of these waves acquired in the deep basin of the south china sea during the winter of 2010 2011 with the goal of assessing the influence of mesoscale variability on their properties combining tidal current simulations with an internal wave generation and evolution model we obtain time series of deviations between our observations and the model simulations these deviations are analyzed in terms of mesoscale variability based on the data assimilated hybrid coordinate ocean model hycom simulations we find that simplified models of nonlinear internal wave response to changes in horizontal stratification gradients and vertical shear provide at best weak simulations of amplitude modulation in contrast to these results deviations of internal wave arrival time occurring up to 2 h early during kuroshio inflows are quite well simulated when derived from integration of the first internal mode phase speed along two dimensional ray traced paths using hycom simulations of velocity and density fields together with bathymetry refraction of the internal waves by kuroshio intrusions can lead to substantial distortion of the paths sufficient to provide a potential explanation for the apparent suppression of waves during previous winter measurements our results suggest that the internal wave field can be a sensitive indicator of mesoscale variability in luzon strait and the northeastern south china sea

organic matter content and quality in supraglacial debris across the ablation zone of the greenland ice sheet quantifying the biogeochemical cycling of carbon in glacial ecosystems is of great significance for regional and potentially global carbon flow estimations the concentration and quality of organic carbon oc is an important indicator of biogeochemical and physical processes that prevail in an ice sheet ecosystem here we determine the content and quality of oc in debris from the surface of the greenland ice sheet gris using microscopic chromatographic spectrophotometric and high temperature combustion techniques the total oc content in the debris increased with distance from the edge of the ice sheet from virtually zero to 6 dry weight at 50 km inland and there was a peak in the carbohydrate proportion and the microbial abundance at 6 km inland the highest galactose mannose arabinose xylose ratios indicating maximum autochthonous microbial production were found at 10 km inland we propose that three key processes influence the carbon cycling on the gris aeolian input of microbial inoculum and nutrients in situ biological c transformation and the wash away of supraglacial debris by meltwaters we show that all these processes have significant spatial variability while the total oc content of the debris on the ice sheet is probably controlled by the physical processes of wind transport and wash away by meltwater the microbial abundance and the quantity of the labile cell contained oc within the debris is likely to be driven by the balance between the wash away and the microbial productivity

a review of internal solitary wave dynamics in the northern south china sea abstract the current research into internal solitary waves isws and the related dynamic processes in the northern south china sea scs are reviewed in this paper this unique wave phenomenon did not draw much interest until about one decade ago and is now one of the hot topics in the field of wave dynamics three methods of investigation are summarized in the paper namely remote sensing images in situ measurements and numerical simulations previous works have primarily been based on one or two of these methods and have provided great insights into such wave phenomena the lifetime of an isw in the northern scs from its origin in the luzon strait ls through to its formation and evolution in the deep basin and its transformation near the shelf break up until its dissipation on the continental shelf is summarized with the illustration of different investigation approaches various factors that can affect the wave generation processes are summed up as well such factors as are barotropic tides in the ls kuroshio intrusion temporal and spatial variation of stratification and the modulation of the western ridge in the ls can significantly alter the wave fields and are extensively discussed

viral dynamics in cryoconite holes on a high arctic glacier svalbard 1 viruses are an abundant and dynamic constituent of microbial communities in aquatic ecosystems in this study we characterized the abundance of viruses associated first with the bottom sediment and overlying water of cryoconite holes and second with shallow ice cores of two different glaciers in svalbard viral abundances were ca 10 100 times lower than the average for marine and freshwater ecosystems in temperate regions virus to bacterium ratios vbr average 10 range between 0 7 and 74 in the water and ice samples and a strong positive correlation between viral and bacterial abundance r 0 93 p 0 01 n 57 indicate that viruses most probably play an important role in controlling bacterial mortality and hence biogeochemical cycling on glaciers samples taken along a transect from the glacier ablation area to proglacial ponds in its forefield showed that viral abundance increased in response to a higher host availability which in turn probably resulted from an increase in temperature and higher mineral levels in the ponds in a transplantation experiment viruses from cryoconite holes were incubated with a bacterial community from a proglacial lake results from the transplantation experiment showed that viruses from cryoconite holes were able to infect bacteria from proglacial lakes and thus influence biogeochemical cycles across different glacial ecosystems our data therefore suggest that viruses in cryoconite holes may be able to infect a broad range of bacterial species

statistical and dynamical analyses of generation mechanisms of solitary internal waves in the northern south china sea 1 this study analyzes the effects of thermocline shoaling on the ocean internal wave iw generation in the north south china sea nscs seven years of satellite synthetic aperture radar sar images from 1995 to 2001 are used for the statistical analysis of iw occurrence and field measurements of sea surface wind sea state and vertical temperature profiles are used for analyzing iw generation and sar imaging conditions latitudinal distribution of iw packets shows that 22 of iw packets distributed in the east of 118e obviously originate from the luzon strait and 78 of iw packets west of 118e may propagate from the east or evolve into the solitons originating from the east boundary owing to the fission effect of shoaling thermocline the yearly distribution of iw occurrence frequencies reveals an interannual variability implying that there are long term and large scale processes modifying the sar observed iw occurrence the monthly sar observed iwoccurrence frequencies show that the high frequencies are distributed from april to july and reach a peak in june with a maximum frequency of 20 the low occurrence frequencies are distributed in winter from december to february of next year with a minimum frequency of 1 5 in february this study proposes that the iw generation needs the necessary and sufficient conditions initial disturbance formation and wave amplitude growth owing to the dissipation effect on the initial disturbance only fully grown waves have a chance to radiate out of the source region a physical model and pkdvequation are adopted for analyzing the sufficient conditions for solitary iw amplitude growth the results indicate that the thermocline shoaling provides the forcing to soliton amplitude growth so that the soliton amplitude growth ratio sagr serves as a decisive factor for the iw occurrence frequency theoretical analysis predicts a linear relation between the two application of theoretical models to field measurements in the luzon strait gives a correlation coefficient as high as 0 845 with a confidence level of 99 for months from march to november the linear regression gives a correlation coefficient r 2 of 0 6519 and a sagr threshold minimum value of

mechanism of internal waves in the luzon strait 1 this study suggests a western boundary current instability generation mechanism for the ocean internal waves a linear model describing this instability is developed and an analytical solution is derived from a zero order complex frequency wavenumber relation the real part of the relation represents a dispersion relation of the generated internal waves and the imaginary part is an exponential growth rate the dispersion relation describes the wave propagation characteristics while the growth rate represents the instability properties the theoretical results are used for the case of the kuroshio east of the luzon strait based on the analysis it is found that for the westward propagating disturbance the kuroshio west wing is unstable and the east wing is stable while the reverse is true for the eastern propagating disturbance the results are used to interpret satellite sar images of the ocean internal waves which were generated in the luzon strait and propagated westward reasonable estimates for the growth rate and propagation velocity are derived from a scale analysis of the kuroshio east of the luzon strait

simulations of internal solitary wave interactions with mesoscale eddies in the northeastern south china sea abstractwith the combined analysis of synthetic aperture radar image and satellite altimeter data collected in the northeastern south china sea scs this study found one type of distorted phenomenon of internal solitary wave isw with the long front caused by the oceanic mesoscale eddy motivated by these satellite observations the authors carried out numerical experiments using the fully nonhydrostatic and nonlinear mitgcm to investigate the perturbation of isws by an isolated cyclonic or anticyclonic eddy the results show that the isw front is distorted by these oceanic eddies due to the retardation and acceleration effects at their two sides the isw energy along the front is focused onto scattered from the wave fragment where a concave convex pattern is formed and the previously accumulated energy in the focusing region is gradually released after the isw propagates away from the eddies the isw amplitude is modulated greatly by the eddies due to the energy redistribution along the front se

measuring rates of gross photosynthesis and net community production in cryoconite holes a comparison of field methods photosynthesis by microbes on the surfaces of glaciers and ice sheets has the potential to fix carbon alter the albedo of ice surfaces via the production of organic matter and so enhance ice melt it could also be important for supplying labile organic matter and nutrients to in situ and downstream ecosystems this study compares in situ 24 hour incubation methods for measuring rates of gross photosynthesis respiration and net community production ncp in cryoconite holes on three svalbard valley glaciers rates of gross photosynthesis and respiration measured by the co 2 method were closely balanced resulting in rates of ncp close to the detection limit mean of 1 3 g c g 1 d 1 consistent with previous measurements in arctic cryoconite holes this suggests that organic matter within cryoconite holes may be derived largely from allochthonous sources the molar ratio of o 2 to co 2 in incubations gave mean respiratory and photosynthetic quotients of 0 80 0 17 1 x sd and 1 24 0 20 1 x sd respectively the 14 c method typically underestimated rates of gross photosynthesis co 2 method by more than one order of magnitude and measured a rate closer to ncp

internal tide radiation from the luzon strait the m2 k1 and o1 internal tides originating in the luzon strait are investigated using the sea surface height measurements by multiple satellites ers 2 envisat topex poseidon jason 1 2 and geosat follow on a plane wave fit method is used to resolve multiple internal tides in arbitrary horizontal directions the luzon strait is an energetic internal tide generation site and radiates internal tides both westward into the south china sea scs and eastward into the western pacific wp in the scs the k1 and o1 internal tides propagate over 1600 km reaching the vietnam coast in the wp they propagate over 2500 km and arrive to the mariana ridge and guam the k1 and o1 internal tides refract toward the equator during propagation the m2 internal tides in the scs bifurcate into two beams the northwestward beam is coincident with the frequent occurrence of internal solitary waves in this region implying their causative relation the phase speeds inferred from the altimetric along beam propagation agree with the theoretical values due to the influence of the earth s rotation the k1 and o1 phase speeds decrease remarkably from high to low latitudes for the diurnal internal tides the eastward radiation is about 50 greater than the westward radiation for m2 the westward radiation is about two times the eastward radiation the altimetric energy fluxes are about 50 of those in numerical model simulations

growth and dissipation of typhoon forced solitary continental shelf waves in the northern south china sea this study aims to gain insight into the sea level response to typhoon in the northern south china sea using typhoon records from 1978 to 1997 simultaneous tidal gauge records and satellite altimeter along track sea level data we find that the ocean sea level response signatures in the deep water agree well with a single sea level soliton of which the average soliton amplitude is 34 6 cm and the average characteristic half width is 115 12 km evolution of the single soliton as propagating across a shoaling bottom topography obeys solutions of the perturbed korteweg and de vries equation the solutions reveal that forced by the hyperbolic tangent shaped topography the single soliton evolves to a solitary wave packet consisting of a large leading soliton and smaller following waves in an oscillatory tail as approaching the shallow water this phenomenon is verified by observed sea level signatures of 19 storm surges the correlation coefficient between theoretical solution and observations is as high as 0 91 meanwhile the soliton amplitude grows with a soliton amplitude growth ratio sagr which depends on the deep water and shallow water depths however without consideration of viscous effects the sagr model overestimates the soliton amplitude growth thus the vorticity equation for viscous fluid is adopted to solve this issue the results indicate that turbulent viscosities are responsible to soliton amplitude decay concurring with the growth and causes dependence of the storm surge amplitude on the typhoon incident angle

evolution of nonlinear internal waves in the east and south china seas synthetic aperture radar sar images from ers i have been used to study the characteristics of internal waves northeast and south of taiwan in the east china sea and east of hainan island in the south china sea rank ordered packets of internal solitons propagating shoreward from the edge of the continental shelf were observed in the sar images on the basis of the assumption of a semidiurnal tidal origin the wave speed can be estimated and is consistent with the internal wave theory by using the sar images and hydrographic data internal waves of elevation have been identified in shallow water by a thicker mixed layer as compared with the bottom layer on the continental shelf the generation mechanism includes the influences of the tide and the kuroshio intrusion across the continental shelf for the formations of elevation internal waves the effects of water depth on the evolution of solitons and wave packets are modeled by the nonlinear kortweg devries kdv type equation and linked to satellite image observations the numerical calculations of internal wave evolution on the continental shelf have been performed and compared with the sar observations for a case of depression waves in deep water the solitons first disintegrate into dispersive wave trains and then evolve to a packet of elevation waves in the shallow water area after they pass through a turning point of approximately equal layer depths that has been observed in the sar image and simulated by the numerical model the importance of the dissipation effect in the coastal area is also discussed and demonstrated

early neoproterozoic origin of the metazoan clade recorded in carbonate rock texture comment neuweiler et al 2009 1 present petrographic work from three carbonate bioherms from modern paleozoic and neoproterozoic aged material they argue that in the three case studies there is textural evidence for calcification of sponge extracellular collagenous matrix ecm pushing back the