Unusually loud ambient noise in tidewater glacier fjords: a signal of ice melt

USGS Publications Warehouse

Pettit, Erin C.; Lee, Kevin M.; Brann, Joel P.; Nystuen, Jeffrey A.; Wilson, Preston S.; O'Neel, Shad

2015-01-01

In glacierized fjords, the ice-ocean boundary is a physically and biologically dynamic environment that is sensitive to both glacier flow and ocean circulation. Ocean ambient noise offers insight into processes and change at the ice-ocean boundary. Here we characterize fjord ambient noise and show that the average noise levels are louder than nearly all measured natural oceanic environments (significantly louder than sea ice and non-glacierized fjords). Icy Bay, Alaska has an annual average sound pressure level of 120 dB (re 1 μPa) with a broad peak between 1000 and 3000 Hz. Bubble formation in the water column as glacier ice melts is the noise source, with variability driven by fjord circulation patterns. Measurements from two additional fjords, in Alaska and Antarctica, support that this unusually loud ambient noise in Icy Bay is representative of glacierized fjords. These high noise levels likely alter the behavior of marine mammals.

A simple approach to adjust tidal forcing in fjord models

NASA Astrophysics Data System (ADS)

Hjelmervik, Karina; Kristensen, Nils Melsom; Staalstrøm, André; Røed, Lars Petter

2017-07-01

To model currents in a fjord accurate tidal forcing is of extreme importance. Due to complex topography with narrow and shallow straits, the tides in the innermost parts of a fjord are both shifted in phase and altered in amplitude compared to the tides in the open water outside the fjord. Commonly, coastal tide information extracted from global or regional models is used on the boundary of the fjord model. Since tides vary over short distances in shallower waters close to the coast, the global and regional tidal forcings are usually too coarse to achieve sufficiently accurate tides in fjords. We present a straightforward method to remedy this problem by simply adjusting the tides to fit the observed tides at the entrance of the fjord. To evaluate the method, we present results from the Oslofjord, Norway. A model for the fjord is first run using raw tidal forcing on its open boundary. By comparing modelled and observed time series of water level at a tidal gauge station close to the open boundary of the model, a factor for the amplitude and a shift in phase are computed. The amplitude factor and the phase shift are then applied to produce adjusted tidal forcing at the open boundary. Next, we rerun the fjord model using the adjusted tidal forcing. The results from the two runs are then compared to independent observations inside the fjord in terms of amplitude and phases of the various tidal components, the total tidal water level, and the depth integrated tidal currents. The results show improvements in the modelled tides in both the outer, and more importantly, the inner parts of the fjord.

The lively Aysén fjord, Chile: Records of multiple geological processes

NASA Astrophysics Data System (ADS)

Lastras, Galderic; Amblas, David; Calafat, Antoni; Canals, Miquel; Frigola, Jaime; Hermanns, Reginald L.; Lafuerza, Sara; Longva, Oddvar; Micallef, Aaron; Sepúlveda, Sergio A.; Vargas, Gabriel; Azpiroz, María; Bascuñán, Ignacio; Duhart, Paul; Iglesias, Olaia; Kempf, Philipp; Rayo, Xavier

2014-05-01

The Aysén fjord is a 65 km long, east-west oriented fjord in Chilean Patagonia, located approximately at 45.4ºS and 73.2ºW, with a maximum water depth of 345 m. The fjord receives at present the riverine input of Aysén, Pescado, Condor and Cuervo rivers, which drain the surrounding up to 2000 m high Patagonian Andes. The fjord is crossed by a number of faults associated to the seismically active Liquiñe-Ofqui Fault Zone, a major trench parallel intra-arc fault system. After a four-month period of moderate seismicity, an Mw 6.2 earthquake on 21 April 2007 triggered dozens of subaerial landslides along the fjord flanks. Some of the landslides reached the fjord water mass, generating a series of tsunami-like displacement waves that impacted the adjacent coastlines with 3-12 m, locally over 50 m high run-ups, causing ten fatalities and severe damage to salmon farms. The research cruise DETSUFA on board BIO Hespérides in March 2013 mapped the submerged morphology of the fjord and gathered air-gun seismic profiles and sediment gravity cores in order to characterise the footprint of the landslides in the fjord floor. Very-high resolution multibeam bathymetry (4 m cell size) clearly shows the deformation structures created by the landslides in the inner fjord. The landslides descended and accelerated down the submerged fjord flanks, and reached the fjord floor at approx. 200 m water depth generating large, 1 to 10 m deep impact depressions. Sediment removed from these depressions moved radially and piled up in deformation rings formed by compressional ridges 10-15 m in height, block fields and a narrow frontal depression. Up to six >1.5 square km of these structures can be identified in the fjord. In addition, the DETSUFA survey extended beyond the SE-NW-oriented inner fjord past the Cuervo Ridge, located in front of the Cuervo river delta. The ridge, previously interpreted as a volcanic transverse structure, has most probably acted as a limit for grounding ice in the past, as suggested by the presence of melt-water channels lateral to the ridge. Beyond the ridge, the fjord smoothens and deepens to more than 330 m forming an enclosed basin before turning SW. There, it shallows back across a field of streamlined submerged hills of glacial origin. The external Aysén fjord, before joining to Canal Costa and Canal Moraleda, is characterized by three volcanic cones, one of them forming Isla Colorada - which also acted as a glacial limit - and the other two totally submerged and previously unknown. The largest one is 160 m high, 1.3 km in diameter and tops at 67 m water depth. This data set illustrates the complex interaction between fluvial, glacial, tectonic, volcanic and gravity processes and evidences the recent lively geological history of Aysén fjord.

Seasonal Rates of Methane Oxidation in Anoxic Marine Sediments

PubMed Central

Iversen, Niels; Blackburn, T. Henry

1981-01-01

Methane concentrations and rates of methane oxidation were measured in intact sediment cores from an inshore marine sediment at Jutland, Denmark. The rates of methane oxidation, determined by the appearance of 14CO2 from injected 14CH4, varied with sediment depth and season. Most methane oxidation was anoxic, but oxygen may have contributed to methane oxidation at the sediment surface. Cumulative rates (0- to 12-cm depth) for methane oxidation at Kysing Fjord were 3.34, 3.48, 8.60, and 17.04 μmol m−2 day−1 for April (4°C), May (13°C), July (17°C), and August (21°C), respectively. If all of the methane was oxidized by sulfate, it would account for only 0.01 to 0.06% of the sulfate reduction. The data indicate that methane was produced, in addition to being oxidized, in the 0- to 18-cm sediment stratum. PMID:16345784

Carbon Dynamics Along a Temperate Fjord-Head Delta: Linkages With Carbon Burial in Fjords

NASA Astrophysics Data System (ADS)

Cui, Xingqian; Bianchi, Thomas S.; Kenney, William F.; Wang, Jiaze; Curtis, Jason H.; Xu, Kehui; Savage, Candida

2017-12-01

We used seven 210Pb-dated sediment cores from the Gaer Arm in the Doubtful Sound fjord complex, Fiordland, New Zealand to evaluate organic carbon (OC) dynamics in a temperate fjord-head delta. The highly dynamic spatial features of this delta were clearly evident in the observed sediment properties such as mass accumulation rates that varied by a factor of 14, sediment grain size by a factor 5, and sedimentary OC content by a factor 6. Low lignin concentrations (e.g., 2.95 mg (100 mg OC)-1) and syringic/vanillic ratios of lignin phenols (S/V; e.g., 0.44) at the upper deltaic stations were representative of substantial autochthonous OC contributions to delta sediments. Significantly higher acid/aldehyde ratios of vanillic phenols [(Ad/Al)v] at the deltaic stations (0.45-0.82) than the surface grabs (0.26-0.30) indicated rapid degradation of OC within the delta. Despite being a "hot spot" for OC oxidation, the delta likely improves OC preservation in the adjacent fjord by filtering out coarse-grained particles and exporting fine-grained particles to fjord sediments. Our results showed that fjord-head deltas can influence sedimentation and OC dynamics in select regions of fjords and thus warrant more examination of fjord-head processes, particularly in areas where they are expanding. In particular, as Earth warms and glaciers retreat, the newly exposed fjord-head platforms in high-latitude environments may evolve into similar "hot spots" of OC oxidation, thereby altering the dynamics of OC burial in these systems.

Influence of Barrier Wind Forcing on Heat Delivery Toward the Greenland Ice Sheet

NASA Astrophysics Data System (ADS)

Fraser, Neil J.; Inall, Mark E.

2018-04-01

A high-resolution numerical hydrodynamic model of Kangerdlugssuaq Fjord and the adjacent southeast Greenland shelf region was constructed in order to investigate the dynamics of fjord-shelf exchange. Recent studies have suggested that rapid exchange flows, driven by along-shelf barrier wind events, are the dominant agent of exchange between fjord and shelf. These events are prone to occur during the winter, when freshwater forcing is minimal and observations of the fjord interior are scarce. Subglacial freshwater discharge was held at zero, so that any buoyancy-driven overturning circulation was driven by melting alone. The model described a geostrophically balanced background flow transporting water masses between the fjord mouth and the glacier terminus, indicating that rotational effects are of order-one importance. Barrier wind events were found to trigger coastally trapped internal wave activity within fjord, temporarily enhancing exchange and vertical mixing, and causing warm water to oscillate in the along-fjord direction. These internal waves were also found to enhance the background flow via Stokes' drift. Heat delivery through the fjord mouth was smaller than that recorded in summer observations, however the system is more effective at delivering this heat to the head of the fjord. There exists the potential for wintertime melting at the ice-ocean interface to be significant to the same order as summertime melting.

On the response of the horizontal mean vertical density distribution in a fjord to low-frequency density fluctuations in the coastal water

NASA Astrophysics Data System (ADS)

Stigebrandt, Anders

1990-10-01

Baroclinic water exchange through a fjord mouth, driven by a slowly varying density field outside the mouth, is modelled by a simple quasi-steady frictionless model. It is assumed that a certain fraction of the horizontal pressure difference between the coastal water and the fjord is used to accelerate the fluid into the mouth. The continuous vertical density distribution in the fjord, which changes in response to the water exchange, is modelled using a time-dependent, one-dimensional advective-diffusive 'filling-box' type of model. The model has been tested against an almost one-year-long time series of salinity and temperature from the Ørsta fjord (horizontal surface area about 15km2) on the Norwegian west coast. It is found that for this particular fjord, the mean externally forced baroclinic water exchange is one order of magnitude greater than the mean water exchange driven by the estuarine circulation (600 and 60m3 s1 respectively). Such a vigorous water exchange between a fjord and the external area implies that the time-averaged concentrations of many biological and chemical species above the sill level in the fjord are approximately equal to those in the coastal water outside the fjords.

Modeling the Impact of Fjord-glacier Geometry on Subglacial Plume, Wind, and Tidally-forced Circulation in Outlet Glacier Fjords

NASA Astrophysics Data System (ADS)

Carroll, D.; Sutherland, D.; Nash, J. D.; Shroyer, E.; de Steur, L.; Catania, G. A.; Stearns, L. A.

2016-12-01

The acceleration, retreat, and thinning of Greenland's outlet glaciers coincided with a warming of Atlantic waters, suggesting that marine-terminating glaciers are sensitive to ocean forcing. However, we still lack a precise understanding of what factors control the variability of ocean heat transport toward the glacier terminus. Here we use an idealized ocean general circulation model (3D MITgcm) to systematically evaluate how fjord circulation driven by subglacial plumes, wind stress (along-fjord and along-shelf), and tides depends on grounding line depth, fjord width, sill height, and latitude. Our results indicate that while subglacial plumes in deeply grounded systems can draw shelf waters over a sill and toward the glacier, shallowly grounded systems require external forcing to renew basin waters. We use a coupled sea ice model to explore the competing influence of tidal mixing and surface buoyancy forcing on fjord stratification. Passive tracers injected in the plume, fjord basin, and shelf waters are used to quantify turnover timescales. Finally, we compare our model results with a two-year mooring record to explain fundamental differences in observed circulation and hydrography in Rink Isbræ and Kangerlussuup Sermia fjords in west Greenland. Our results underscore the first-order effect that geometry has in controlling fjord circulation and, thus, ocean heat flux to the ice.

Recent oxygen depletion and benthic faunal change in shallow areas of Sannäs Fjord, Swedish west coast

NASA Astrophysics Data System (ADS)

Nordberg, Kjell; Polovodova Asteman, Irina; Gallagher, Timothy M.; Robijn, Ardo

2017-09-01

Sannäs Fjord is a shallow fjord (< 32 m w.d.) with a sill depth of 8 m, located at the Swedish west coast of the Skagerrak (North Sea). The anthropogenic impact on the fjord represents combination of sewage from the local village of Sannäs and land run-off from agricultural areas. Sewage impact has been reduced since 1991 and today the fjord is included into several nature conservation programs administrated by the European Union. Yet, observations during the summers of 2008-2011 show that the shallow inner fjord inlet experiences severe oxygen depletion at 5-12 m water depth. To explore if the oxygen depletion is only a recent phenomenon and to evaluate the potential of fjord sediments to archive such environmental changes, in 2008 and 2009 seven sediment cores were taken along a transect oriented lengthwise in the fjord. The cores were analysed for organic carbon, C/N, benthic foraminifera and lead pollution records (as relative age marker). Carbon content increases in most of the cores since the 1970-80s, while C/N ratio decreases from the core base upward since 1995. Foraminiferal assemblages in most core stratigraphies are dominated by agglutinated species. Calcareous species (mainly elphidiids) have become dominant in the upper part of the records since the late 1990s or 2000 (the inner fjord and the deepest basin) and since the 1950-70s (the outer fjord). In the inner Sannäs Fjord, an increase of agglutinated foraminiferal species (e.g. Eggerelloides scaber) and organic inner linings occurred since the 1970s, suggesting an intensification of taphonomic processes affecting postmortem calcareous shell preservation. A study of living vs. dead foraminiferal assemblages undertaken during June-August 2013 demonstrates that in the shallow inner fjord, strong carbonate dissolution occurs within 1-3 months following the foraminiferal growth. The dissolution is linked to corrosive conditions present within the sediment - bottom water interface, and is likely caused by the organic matter decay, resulting in severe hypoxia to anoxia. Oxygen depletion at < 10 m w.d. develops fast due to the small water volume and limited bottom water exchange caused by a close proximity of pycnocline to the fjord bottom. Sediment cores from the deep fjord basin and the outer fjord are, on the contrary, characterized by good to excellent preservation of foraminiferal shells, higher sediment accumulation rates, and the greatest potential for high-resolution paleoenvironmental studies. Increased frequencies of low-oxygen tolerant species (e.g. Stainforthia fusiformis) in the outer fjord after the 1970s suggests that increased primary productivity and seasonal oxygen deficiency have existed in the area over the last century. Recent milder winters, absent sediment reworking by freezing and grounding of sea-ice, increased nutrient load due to higher precipitation and land run-off, and the luxuriant growth of filamentous green algae followed by the organic matter decay are discussed among the mechanisms driving formation of recent oxygen deficiency in the shallow fjord inlets.

Earthquakes, Subaerial and Submarine Landslides, Tsunamis and Volcanoes in Aysén Fjord, Chile

NASA Astrophysics Data System (ADS)

Lastras, G.; Amblas, D.; Calafat-Frau, A. M.; Canals, M.; Frigola, J.; Hermanns, R. L.; Lafuerza, S.; Longva, O.; Micallef, A.; Sepulveda, S. A.; Vargas Easton, G.; Azpiroz, M.; Bascuñán, I.; Duhart, P.; Iglesias, O.; Kempf, P.; Rayo, X.

2014-12-01

The Aysén fjord, 65 km long and east-west oriented, is located at 45.4ºS and 73.2ºW in Chilean Patagonia. It has a maximum water depth of 345 m. It collects the inputs of Aysén, Pescado, Condor and Cuervo rivers, which drain the surrounding Patagonian Andes. The fjord is crossed by the Liquiñe-Ofqui Fault Zone, a seismically active trench parallel intra-arc fault system. On 21 April 2007, an Mw 6.2 earthquake triggered numerous subaerial and submarine landslides along the fjord flanks. Some of the subaerial landslides reached the water mass, generating tsunami-like displacement waves that flooded the adjacent coastlines, withlocal >50 m high run-ups, causing ten fatalities and damage to salmon farms. The research cruise DETSUFA on board BIO Hespérides in March 2013, aiming to characterise the landslides and their effects, mapped with great detail the submerged morphology of the fjord. Multibeam data display deformation structures created by the impact of the landslides in the inner fjord floor. Landslide material descended and accelerated down the highly sloping fjord flanks, and reached the fjord floor at 200 m water depth generating large, 10-m-deep impact depressions. Fjord floor sediment was pushed and piled up in arcuate deformation areas formed by 15-m-high compressional ridges, block fields and a narrow frontal depression. Up to six >1.5 km2 of these structures have been identified. In addition, the cruise mapped the outer fjord floor beyond the Cuervo ridge. This ridge, previously interpreted as a volcanic transverse structure, most probably acted as a limit for grounding ice in the past, as suggested by the presence of a melt-water channel. The fjord smoothens and deepens to more than 330 m forming an enclosed basin, before turning SW across a field of streamlined hills of glacial origin. Three volcanic cones, one of them forming Isla Colorada and the other two totally submerged and previously unknown, have been mapped in the outer fjord. The largest one is 160 m high, 1.3 km in diameter and tops at 67 m water depth. This high-resolution data set illustrates a wide set of geohazards in the recent lively geological history of Aysén fjord.

Multibeam Mapping of Remote Fjords in Southeast-Greenland

NASA Astrophysics Data System (ADS)

Weinrebe, W.; Kjaer, K. H.; Kjeldsen, K. K.; Bjork, A. A.

2015-12-01

The fjords of Southeast-Greenland are among the most remote areas of the Northern Hemisphere. Access to this area is hampered by a broad belt of sea ice floating along the East-Greenland coast from North to South. Consequently, the majority of those fjords have never been surveyed in detail until now. During an expedition by the Center of GeoGenetics of the University of Copenhagen in summer of 2014 we were able to map the Skjoldungen Fjord system with multibeam bathymetry. The topsail schooner ACTIV, built 1951 as a cargo ship to supply remote settlements in Greenland was chosen for the expedition. Though a vintage vessel, the ACTIV was well suited to cross the belt of sea ice and to cruise the ice covered fjords. A portable ELAC-Seabeam 1050 multibeam system was temporarily installed on the vessel. The two transducer of the system were mounted at the lower end of a 6 m long pole attached outboard at port side to the hull of the vessel. Though the installation was quite demanding without any winches or cranes, the construction was sufficiently stable and easy to manage throughout the entire cruise. Nearly the entire fjord system, leaving only a small gap of 5 km at the innermost part and small stripes close to the shorelines could be surveyed during the cruise. For the first time, a comprehensive map of Skjoldungen Fjord is now available. The map displays water depths from close to zero up to 800 m, the deepest part along a stretch of about 10 km in the Southwest. The bathymetry of the northern fjord is remarkably different from the southern fjord: the southern fjord features an outer deep part showing water depths between 500 m and 800 m and a shallow inner part with depths less than 300 m and a prominent sill in between. The northern fjord shows a more gradual increase of water depths from 200 m in the inner part to 600 m at the entrance.

Greenland's glacial fjords and their role in regional biogeochemical dynamics.

NASA Astrophysics Data System (ADS)

Crosby, J.; Arndt, S.

2017-12-01

Greenland's coastal fjords serve as important pathways that connect the Greenland Ice Sheet (GrIS) and the surrounding oceans. They export seasonal glacial meltwater whilst being significant sites of primary production. These fjords are home to some of the most productive ecosystems in the world and possess high socio-economic value via fisheries. A growing number of studies have proposed the GrIS as an underappreciated yet significant source of nutrients to surrounding oceans. Acting as both transfer routes and sinks for glacial nutrient export, fjords have the potential to act as significant biogeochemical processors, yet remain underexplored. Critically, an understanding of the quantitative contribution of fjords to carbon and nutrient budgets is lacking, with large uncertainties associated with limited availability of field data and the lack of robust upscaling approaches. To close this knowledge gap we developed a coupled 2D physical-biogeochemical model of the Godthåbsfjord system, a sub-Arctic sill fjord in southwest Greenland, to quantitatively assess the impact of nutrients exported from the GrIS on fjord primary productivity and biogeochemical dynamics. Glacial meltwater is found to be a key driver of fjord-scale circulation patterns, whilst tracer simulations reveal the relative nutrient contributions from meltwater-driven upwelling and meltwater export from the GrIS. Hydrodynamic circulation patterns and freshwater transit times are explored to provide a first understanding of the glacier-fjord-ocean continuum, demonstrating the complex pattern of carbon and nutrient cycling at this critical land-ocean interface.

Comparison of earthquake-triggered turbidites from the Saguenay (Eastern Canada) and Reloncavi (Chilean margin) Fjords: Implications for paleoseismicity and sedimentology

NASA Astrophysics Data System (ADS)

St-Onge, Guillaume; Chapron, Emmanuel; Mulsow, Sandor; Salas, Marcos; Viel, Matias; Debret, Maxime; Foucher, Anthony; Mulder, Thierry; Winiarski, Thierry; Desmet, Marc; Costa, Pedro J. M.; Ghaleb, Bassam; Jaouen, Alain; Locat, Jacques

2012-01-01

High-resolution seismic profiles along with physical and sedimentological properties of sediment cores from the Saguenay (Eastern Canada) and Reloncavi (Chile) Fjords allowed the identification of several decimeter to meter-thick turbidites. In both fjords, the turbidites were associated with large magnitude historic and pre-historic earthquakes including the 1663 AD (M > 7) earthquake in the Saguenay Fjord, and the 1960 (M 9.5), 1837 (M ~ 8) and 1575 AD major Chilean subduction earthquakes in the Reloncavi Fjord. In addition, a sand layer with exoscopic characteristics typical of a tsunami deposit was observed immediately above the turbidite associated with the 1575 AD earthquake in the Reloncavi Fjord and supports both the chronology and the large magnitude of that historic earthquake. In the Saguenay Fjord, the earthquake-triggered turbidites are sometimes underlying a hyperpycnite associated with the rapid breaching and draining of a natural dam formed by earthquake-triggered landslides. Similar hyperpycnal floods were also recorded in historical and continental geological archives for the 1960 and 1575 AD Chilean subduction earthquakes, highlighting the risk of such flood events several weeks or months after main earthquake. In both fjords, as well as in other recently recognized earthquake-triggered turbidites, the decimeter-to meter-thick normally-graded turbidites are characterized by a homogeneous, but slightly fining upward tail. Finally, this paper also emphasizes the sensitivity of fjords to record historic and pre-historic seismicity.

Erosion of modern terrestrial organic matter as a major component of sediments in fjords

NASA Astrophysics Data System (ADS)

Cui, Xingqian; Bianchi, Thomas S.; Savage, Candida

2017-02-01

Fjords have recently been recognized as "hot spots" of carbon burial. In this study, we investigated organic carbon (OC) and biomarker radiocarbon values in fjord sediments from New Zealand. Our results showed that OC was mostly modern with the most aged OC in middle reaches of fjords, likely related to hydrodynamic sorting and inputs along adjacent slopes. Radiocarbon ages of sedimentary OC increased from north-to-south, consistent with the Fiordland regional gradients of lower fjord slopes and less rainfall. Our biomarker results suggested that lignin and long-chain fatty acids were preferentially linked with fresh terrestrial debris and degraded soil, respectively, likely due to their chemical and physical properties. Finally, we propose that fjords are a significant sink of modern OC, in contrast to large lowland coastal systems as a major sink of preaged OC. Overall, this study indicated that radiocarbon techniques are critical in investigating carbon dynamics in coastal systems.

Seasonal sea surface and sea ice signal in the fjords of Eastern Greenland from CryoSat-2 SARin altimetry

NASA Astrophysics Data System (ADS)

Abulaitijiang, Adili; Baltazar Andersen, Ole; Stenseng, Lars

2014-05-01

Cryosat-2 offers the first ever possibility to perform coastal altimetric studies using SAR-Interferometry. This enabled qualified measurements of sea surface height (SST) in the fjords in Greenland. Scoresbysund fjord on the east coast of Greenland is the largest fjord in the world which is also covered by CryoSat-2 SAR-In mask making it a good test region. Also, the tide gauge operated by DTU Space is sitting in Scoresbysund bay, which provides solid ground-based sea level variation records throughout the year. We perform an investigation into sea surface height variation since the start of the Cryosat-2 mission using SAR-In L1B data processed with baseline B processing. We have employed a new develop method for projecting all SAR-In observations in the Fjord onto a centerline up the Fjord. Hereby we can make solid estimates of the annual and (semi-) annual signal in sea level/sea ice freeboard within the Fjord. These seasonal height variations enable us to derive sea ice freeboard changes in the fjord from satellite altimetry. Derived sea level and sea-ice freeboard can be validated by comparison with the tide gauge observations for sea level and output from the Microwave Radiometer derived observations of sea ice freeboard developed at the Danish Meteorological Institute.

Holocene environmental changes recorded in Dicksonfjorden and Woodfjorden, Svalbard: impacts of global climate changes in a glacial-marine system

NASA Astrophysics Data System (ADS)

Joo, Y. J.; Nam, S. I.; Son, Y. J.; Forwick, M.

2017-12-01

Fjords in the Svalbard archipelago are characterized by an extreme environmental gradient between 1) the glacial system affected by tidewater glaciers and seasonal sea ice inside the fjords and 2) the warm Atlantic Water intrusion by the West Spitsbergen Current from open ocean. As sediment is largely supplied from the terrestrial source area exposed along the steep slopes of the fjords, the changes in the surface processes affected by glaciers are likely preserved in the sediments in the inner fjords. On the other hand, variations in the influence of the warm Atlantic Water in the marine realm (e.g. marine productivity) can be archived in the sediment deposited in the vicinity of the entrance to the fjords. Since the last deglaciation of the Svalbard-Barents ice sheet ( 13000 yrs BP), the Svalbard fjords have faced dramatic climate changes including the early Holocene Climate Optimum (HCO) and subsequent cooling that eventually led to the current cold and dry climate. We investigate the Holocene environmental changes in both terrestrial and marine realms based on stable isotopic and inorganic geochemical analyses of sediments deposited in Dicksonfjorden and Woodfjorden in the western and northern Spitsbergen, respectively. The two fjords are expected to provide intriguing information regarding how terrestrial and marine realms of the Arctic fjords system responded to regional and global climate changes. Being a branch of the larger Isfjorden, Dicksonfjorden penetrates deeply to the land, whereas Woodfjorden is rather directly connected to the open ocean. Accordingly, the results suggest that the Dicksonfjorden sediment records mainly terrestrial signals with marked fluctuations in sediment composition that coincide with major climate changes (e.g. HCO). On the contrary, the two Woodfjorden cores collected from different parts of the fjord exhibit contrasting results, likely illustrating differing response of terrestrial and marine realms to the climate changes in terms of behavior of tidewater glaciers and inflow of the warm West Spitsbergen Current and their possible interactions. This study aims to disentangle the interaction between the fjords and the global climate changes and provide a holistic view to the Arctic fjords system with strong environmental gradients.

Seasonal changes in Fe along a glaciated Greenlandic fjord.

NASA Astrophysics Data System (ADS)

Hopwood, Mark; Connelly, Douglas; Arendt, Kristine; Juul-Pedersen, Thomas; Stinchcombe, Mark; Meire, Lorenz; Esposito, Mario; Krishna, Ram

2016-03-01

Greenland's ice sheet is the second largest on Earth, and is under threat from a warming Arctic climate. An increase in freshwater discharge from Greenland has the potential to strongly influence the composition of adjacent water masses with the largest impact on marine ecosystems likely to be found within the glaciated fjords. Here we demonstrate that physical and chemical estuarine processes within a large Greenlandic fjord are critical factors in determining the fate of meltwater derived nutrients and particles, especially for non-conservative elements such as Fe. Concentrations of Fe and macronutrients in surface waters along Godthåbsfjord, a southwest Greenlandic fjord with freshwater input from 6 glaciers, changed markedly between the onset and peak of the meltwater season due to the development of a thin (<10 m), outflowing, low-salinity surface layer. Dissolved (<0.2 µm) Fe concentrations in meltwater entering Godthåbsfjord (200 nM), in freshly melted glacial ice (mean 38 nM) and in surface waters close to a land terminating glacial system (80 nM) all indicated high Fe inputs into the fjord in summer. Total dissolvable (unfiltered at pH <2.0) Fe was similarly high with concentrations always in excess of 100 nM throughout the fjord and reaching up to 5.0 µM close to glacial outflows in summer. Yet, despite the large seasonal freshwater influx into the fjord, Fe concentrations near the fjord mouth in the out-flowing surface layer were similar in summer to those measured before the meltwater season. Furthermore, turbidity profiles indicated that sub-glacial particulate Fe inputs may not actually mix into the outflowing surface layer of this fjord. Emphasis has previously been placed on the possibility of increased Fe export from Greenland as meltwater fluxes increase. Here we suggest that in-fjord processes may be effective at removing Fe from surface waters before it can be exported to coastal seas.

Holocene earthquake-triggered turbidites from the Saguenay (Eastern Canada) and Reloncavi (Chilean margin) fjords

NASA Astrophysics Data System (ADS)

St-Onge, Guillaume; Chapron, Emmanuel; Mulsow, Sandor; Salas, Marcos; Debret, Maxime; Foucher, Anthony; Mulder, Thierry; Desmet, Marc; Costa, Pedro; Ghaleb, Bassam; Locat, Jacques

2013-04-01

Fjords are unique archives of climatic and environmental changes, but also of natural hazards. They can preserve thick sedimentary sequences deposited under very high sediment accumulation rates, making them ideally suited to record historical and pre-historical sedimentological events such as major landslides, floods or earthquakes. In fact, by carefully characterizing and dating the sediments and by comparing the basin fill seismic stratigraphy and sedimentary records with historical events, it is possible to "calibrate" recent rapidly deposited layers such as turbidites with a trigger mechanism and extend these observations further back in time by using seismic reflection profiles and longer sediment cores. Here, we will compare earthquake-triggered turbidites in fjords from the Southern and Northern Hemispheres: the Saguenay (Eastern Canada) and Reloncavi fjords (southern Chilean margin). In both settings, we will first look at basin fill geometries and at the sedimentological properties of historical events before extending the records further back in time. In both fjords, several turbidites were associated with large magnitude historic and pre-historic earthquakes including the 1663 AD (M>7) earthquake in the Saguenay Fjord, and the 1960 (M 9.5), 1837 (M~8) and 1575 AD major Chilean subduction earthquakes in the Reloncavi Fjord. In addition, a sand layer with sea urchin fragments and the exoscopic characteristics typical of a tsunami deposit was observed immediately above the turbidite associated with the 1575 AD earthquake in the Reloncavi Fjord and supports both the chronology and the large magnitude of that historic earthquake. In both fjords, as well as in other recently recognized earthquake-triggered turbidites, the decimeter-to meter-thick normally-graded turbidites are characterized by a homogeneous, but slightly fining upward tail. Finally, new radiocarbon results will be presented and indicate that at least 19 earthquake-triggered turbidites were recorded in the Reloncavi Fjord during the last 7500 cal BP.

Using Icebergs to Constrain Fjord Circulation and Link to Glacier Dynamics

NASA Astrophysics Data System (ADS)

Sutherland, D.; Straneo, F.; Hamilton, G. S.; Stearns, L. A.; Roth, G.

2014-12-01

The importance of icebergs is increasingly being recognized in the ocean-glacier interactions community. Icebergs are ubiquitous in Greenland's outlet glacial fjords and provide a physical link between the glacier and the ocean into which they melt. The iceberg shape is influenced by glacier size and calving mechanics, while the amount of melt produced depends on ambient water properties and the residence time of the iceberg in the fjord. Here, we use hourly positions of icebergs tracked with helicopter deployed GPS sensors to calculate velocities in the Sermilik Fjord/Helheim Glacier system. Data comes from three summertime deployments in 2012-2014, where icebergs were tagged in the ice mélange and moved through the fjord and onto the continental shelf. The iceberg-derived velocities provide information on ice mélange movement, fjord variability, and coastal currents on the shelf. Using simple melt rate parameterizations, we estimate the total freshwater input due to iceberg melt in Sermilik Fjord based on the observed residence times and satellite-derived iceberg distributions. These observations complement conventional oceanographic and glaciological data, and can quickly, and relatively inexpensively, characterize circulation throughout any given glacier-ocean system.

Linking bacterial community structure to advection and environmental impact along a coast-fjord gradient of the Sognefjord, western Norway

NASA Astrophysics Data System (ADS)

Storesund, Julia E.; Sandaa, Ruth-Anne; Thingstad, T. Frede; Asplin, Lars; Albretsen, Jon; Erga, Svein Rune

2017-12-01

Here we present novel data on bacterial assemblages along a coast-fjord gradient in the Sognefjord, the deepest (1308 m) and longest (205 km) ice-free fjord in the world. Data were collected on two cruises, one in November 2012, and one in May 2013. Special focus was on the impact of advective processes and how these are reflected in the autochthonous and allochthonous fractions of the bacterial communities. Both in November and May bacterial community composition, determined by Automated Ribosomal Intergenic Spacer Analyses (ARISA), in the surface and intermediate water appeared to be highly related to bacterial communities originating from freshwater runoff and coastal water, whereas the sources in the basin water were mostly unknown. Additionally, the inner part of the Sognefjord was more influenced by side-fjords than the outer part, and changes in bacterial community structure along the coast-fjord gradient generally showed higher correlation with environmental variables than with geographic distances. High resolution model simulations indicated a surprisingly high degree of temporal and spatial variation in both current speed and direction. This led to a more episodic/discontinuous horizontal current pattern, with several vortices (10-20 km wide) being formed from time to time along the fjord. We conclude that during periods of strong wind forcing, advection led to allochthonous species being introduced to the surface and intermediate layers of the fjord, and also appeared to homogenize community composition in the basin water. We also expect vortices to be active mixing zones where inflowing bacterial populations on the southern side of the fjord are mixed with the outflowing populations on the northern side. On average, retention time of the fjord water was sufficient for bacterial communities to be established.

The Ocean's Role in Outlet Glacier Variability: A Case Study from Uummannaq, Greenland

NASA Astrophysics Data System (ADS)

Sutherland, D.; Catania, G. A.; Bartholomaus, T. C.; Nash, J. D.; Shroyer, E.; Walker, R. T.; Stearns, L. A.

2014-12-01

The dynamics controlling the coupling between fjord circulation and outlet glacier movement are poorly understood. Here, we use oceanographic data collected from 2013-2014 from two west Greenland fjords, Rink Isbrae and Kangerdlugssup Sermerssua, to constrain the spatial and temporal variability observed in fjord circulation. We aim to quantify the ocean's role, if any, in explaining the marked differences in glacier behavior from two systems that are in close proximity to one another. Combining time series data from a set of subsurface moorings with repeat transects in each fjord allows an unprecedented look at the temporal and spatial variability in circulation. We find significant differences in the variability in each fjord and discuss the implications for the glaciers.

Glacial runoff strongly influences food webs in Gulf of Alaska fjords

NASA Astrophysics Data System (ADS)

Arimitsu, M.; Piatt, J. F.; Mueter, F. J.

2015-12-01

Melting glaciers contribute large volumes of freshwater to the Gulf of Alaska coast. Rates of glacier volume loss have increased markedly in recent decades, raising concern about the eventual loss of glaciers as a source of freshwater in coastal waters. To better understand the influence of glacier melt water on fjord ecosystems, we sampled oceanography, nutrients, zooplankton, forage fish, and seabirds within four fjords in the coastal Gulf of Alaska. We used generalized additive models and geostatistics to identify the range of influence of glacier runoff in fjords of varying estuarine and topographic complexity. We also modeled the responses of chlorophyll a concentration, copepod biomass, fish and seabird abundance to physical, nutrient and biotic predictor variables. Physical and nutrient signatures of glacial runoff extended 10-20 km into coastal fjords. Glacially modified physical gradients and among-fjord differences explained 66% of the variation in phytoplankton abundance, which drives ecosystem structure at higher trophic levels. Copepod, euphausiid, fish and seabird distribution and abundance were also related to environmental gradients that could be traced to glacial freshwater input. Seabird density was predicted by prey availability and silica concentrations, which may indicate upwelling areas where this nutrient is in excess. Similarities in ecosystem structure among fjords were due to influx of cold, fresh, sediment and nutrient laden water, while differences were due to fjord topography and the relative importance of estuarine vs. ocean influences. We anticipate continued changes in the volume and magnitude of glacial runoff will affect coastal marine food webs in the future.

Influence of glacier runoff on ecosystem structure in Gulf of Alaska fjords

USGS Publications Warehouse

Arimitsu, Mayumi L.; Piatt, John F.; Mueter, Franz J.

2016-01-01

To better understand the influence of glacier runoff on fjord ecosystems, we sampled oceanographic conditions, nutrients, zooplankton, forage fish and seabirds within 4 fjords in coastal areas of the Gulf Alaska. We used generalized additive models and geostatistics to identify the range of glacier runoff influence into coastal waters within fjords of varying estuarine influence and topographic complexity. We also modeled the response of depth-integrated chlorophyll a concentration, copepod biomass, fish and seabird abundance to physical, nutrient and biotic predictor variables. The effects of glacial runoff were traced at least 10 km into coastal fjords by cold, turbid, stratified and generally nutrient-rich near-surface conditions. Glacially modified physical gradients, nutrient availability and among-fjord differences explained 67% of the variation in phytoplankton abundance, which is a driver of ecosystem structure at higher trophic levels. Copepod, euphausiid, fish and seabird distribution and abundance were related to environmental gradients that could be traced to glacial freshwater input, particularly turbidity and temperature. Seabird density was predicted by prey availability and silicate concentrations, which may be a proxy for upwelling areas where this nutrient is in excess. Similarities in ecosystem structure among fjords were attributable to an influx of cold, fresh and sediment-laden water, whereas differences were likely related to fjord topography and local differences in estuarine vs. ocean influence. We anticipate that continued changes in the timing and volume of glacial runoff will ultimately alter coastal ecosystems in the future.

Novel Measurements and Techniques for Outlet Glacier Fjord Ice/Ocean Interactions

NASA Astrophysics Data System (ADS)

Behar, A.; Howat, I. M.; Holland, D. M.; Ahlstrom, A. P.; Larsen, S. H.

2014-12-01

Glacier fjord bathymetry and conditions indicate that they play fundamental roles for outlet glacier dynamics and thus knowledge of these parameters is extremely beneficial to upcoming models that predict changes. In particular, the bathymetry of a fjord gives important information about the exchange between fjord waters close to marine-terminating glaciers and the shelf and ocean. Currently, only sparse bathymetric data near the ice fronts are available for the majority of fjords in Greenland. The challenge in obtaining these measurements is that the fjord melange environment is a terrible one for mechanical gear, or ship or any other kind of access. There is hope however, and this work focuses on novel ways of obtaining this data using a multitude of upcoming technologies and techniques that are now being tested and planned. The span of the techniques described include but are not limited to: 1) manned helicopter-based live-reading instruments and deployable/retriavable sensor packages http://www.motionterra.com/fjord/ 2) remote or autonomous unmanned miniature boats (Depth/CTD), and 3) UAV's that either read live data or deploy small sensors that can telemeter their data (ice-flow trackers, image acquisition, etc.). A review of current results obtained at Jakobshavn and Upernavik Glaciers will be given as well as a description of the techniques and hardware used.

Oceanic response to buoyancy, wind and tidal forcing in a Greenlandic glacial fjord

NASA Astrophysics Data System (ADS)

Carroll, D.; Sutherland, D.; Shroyer, E.; Nash, J. D.

2013-12-01

The Greenland Ice Sheet is losing mass at an accelerating rate. This acceleration may in part be due to changes in oceanic heat transport to marine-terminating outlet glaciers. Ocean heat transport to glaciers depends upon fjord dynamics, which include buoyancy-driven estuarine exchange flow, tides, internal waves, turbulent mixing, and connections to the continental shelf. A 3D model of Rink Isbrae fjord in West Greenland is used to investigate the role of ocean forcing on heat transport to the glacier face. Initial conditions are prescribed from oceanographic field data collected in Summer 2013; wind and tidal forcing, along with meltwater flux, are varied in individual model runs. Subglacial meltwater flux values range from 25-500 m3 s-1. For low discharge values, a subsurface plume drives circulation in the fjord. Our simulations indicate that offshore wind forcing is the dominant mechanism for exchange flow between the fjord and the continental shelf. These results show that glacial fjord circulation is a complex, 3D process with multi-cell estuarine circulation and large velocity shears due to coastal winds. Our results are a first step towards a realistic 3D representation of a high-latitude glacial fjord in a numerical model, and will provide insight to future observational studies.

Distribution pattern of benthic invertebrates in Danish estuaries: The use of Taylor's power law as a species-specific indicator of dispersion and behavior

NASA Astrophysics Data System (ADS)

Kristensen, Erik; Delefosse, Matthieu; Quintana, Cintia O.; Banta, Gary T.; Petersen, Hans Christian; Jørgensen, Bent

2013-03-01

The lack of a common statistical approach describing the distribution and dispersion pattern of marine benthic animals has often hampered the comparability among studies. The purpose of this study is therefore to apply an alternative approach, Taylor's power law, to data on spatial and temporal distribution of 9 dominating benthic invertebrate species from two study areas, the estuaries Odense Fjord and Roskilde Fjord, Denmark. The slope (b) obtained from the power relationship of sample variance (s2) versus mean (μ) appears to be species-specific and independent of location and time. It ranges from a low of ~ 1 for large-bodied (> 1 mg AFDW) species (e.g. Marenzelleria viridis, Nereis diversicolor) to a high of 1.6-1.9 for small-bodied (< 1 mg AFDW) species (e.g. Pygospio elegans and Tubificoides benedii). Accordingly, b is apparently a valuable species-specific dispersion index based on biological factors such as behavior and intraspecific interactions. Thus, at the examined spatial scale, the more intense intraspecific interactions (e.g. territoriality) cause less aggregated distribution patterns among large- than small-bodied invertebrates. The species-specific interactions seem sufficiently strong to override environmental influences (e.g. water depth and sediment type). The strong linear relationship between the slope b and intercept log(a) from the power relationship is remarkably similar for all surveys providing a common slope of - 1.63 with the present sampling approach. We suggest that this relationship is an inherent characteristic of Taylor's power law, and that b as a dispersion index may be biased by e.g. sampling errors when this relationship is weak. The correlation strength between b and log(a) could therefore be envisioned as a data quality check.

Scotland's forgotten carbon: a national assessment of mid-latitude fjord sedimentary carbon stocks

NASA Astrophysics Data System (ADS)

Smeaton, Craig; Austin, William E. N.; Davies, Althea L.; Baltzer, Agnes; Howe, John A.; Baxter, John M.

2017-12-01

Fjords are recognised as hotspots for the burial and long-term storage of carbon (C) and potentially provide a significant climate regulation service over multiple timescales. Understanding the magnitude of marine sedimentary C stores and the processes which govern their development is fundamental to understanding the role of the coastal ocean in the global C cycle. In this study, we use the mid-latitude fjords of Scotland as a natural laboratory to further develop methods to quantify these marine sedimentary C stores on both the individual fjord and national scale. Targeted geophysical and geochemical analysis has allowed the quantification of sedimentary C stocks for a number of mid-latitude fjords and, coupled with upscaling techniques based on fjord classification, has generated the first full national sedimentary C inventory for a fjordic system. The sediments within these mid-latitude fjords hold 640.7 ± 46 Mt of C split between 295.6 ± 52 and 345.1 ± 39 Mt of organic and inorganic C, respectively. When compared, these marine mid-latitude sedimentary C stores are of similar magnitude to their terrestrial equivalents, with the exception of the Scottish peatlands, which hold significantly more C. However, when area-normalised comparisons are made, these mid-latitude fjords are significantly more effective as C stores than their terrestrial counterparts, including Scottish peatlands. The C held within Scotland's coastal marine sediments has been largely overlooked as a significant component of the nation's natural capital; such coastal C stores are likely to be key to understanding and constraining improved global C budgets.

Organic carbon burial in fjords: Terrestrial versus marine inputs

NASA Astrophysics Data System (ADS)

Cui, Xingqian; Bianchi, Thomas S.; Savage, Candida; Smith, Richard W.

2016-10-01

Fjords have been identified as sites of enhanced organic carbon (OC) burial and may play an important role in regulating climate change on glacial-interglacial timescales. Understanding sediment processes and sources of sedimentary OC are necessary to better constrain OC burial in fjords. In this study, we use Fiordland, New Zealand, as a case study and present data on surface sediments, sediment down-cores and terrestrial end-members to examine dynamics of sediments and the sources of OC in fjord sediments. Sediment cores showed evidence of multiple particle sources, frequent bioturbation and mass-wasting events. A multi-proxy approach (stable isotopes, lignin-phenols and fatty acids) allowed for separation of marine, soil and vascular plant OC in surface sediments. The relationship between mass accumulation rate (MAR) and OC contents in fjord surface sediments suggested that mineral dilution is important in controlling OC content on a global scale, but is less important for specific regions (e.g., New Zealand). The inconsistency of OC budgets calculated by using MAR weighted %OC and OC accumulation rates (AR; 6 vs 21-31 Tg OC yr-1) suggested that sediment flux in fjords was likely underestimated. By using end-member models, we propose that 55% to 62% of total OC buried in fjords is terrestrially derived, and accounts for 17 ± 12% of the OCterr buried in all marine sediments. The strong correlation between MAR and OC AR indicated that OC flux will likely decrease in fjords in the future with global warming due to decrease in sediment flux caused by glacier denudation.

College Fjord, Prince Williams Sound

NASA Image and Video Library

2001-07-21

The College Fjord with its glaciers was imaged by ASTER on June 24, 2000. This image covers an area 20 kilometers (13 miles) wide and 24 kilometers (15 miles) long in three bands of the reflected visible and infrared wavelength region. College Fjord is located in Prince Williams Sound, east of Seward, Alaska. Vegetation is in red, and snow and ice are white and blue. Ice bergs calved off of the glaciers can be seen as white dots in the water. At the head of the fjord, Harvard Glacier (left) is one of the few advancing glaciers in the area; dark streaks on the glacier are medial moraines: rock and dirt that indicate the incorporated margins of merging glaciers. Yale Glacier to the right is retreating, exposing (now vegetated) bedrock where once there was ice. On the west edge of the fjord, several small glaciers enter the water. This fjord is a favorite stop for cruise ships plying Alaska's inland passage. This image is located at 61.2 degrees north latitude and 147.7 degrees west longitude. http://photojournal.jpl.nasa.gov/catalog/PIA02664

In situ evaluation of air-sea CO2 gas transfer velocity in an inner estuary using eddy covariance - with a special focus on the importance of using reliable CO2-fluxes

NASA Astrophysics Data System (ADS)

Jørgensen, E. T.; Sørensen, L. L.; Jensen, B.; Sejr, M. K.

2012-04-01

The air-sea exchange of CO2 or CO2 flux is driven by the difference in the partial pressure of CO2 in the water and the atmosphere (ΔpCO2), the solubility of CO2 (K0) and the gas transfer velocity (k) (Wanninkhof et al., 2009;Weiss, 1974) . ΔpCO2 and K0 are determined with relatively high precision and it is estimated that the biggest uncertainty when modelling the air-sea flux is the parameterization of k. As an example; the estimated global air-sea flux increases by 70 % when using the parameterization by Wanninkhof and McGillis (1999) instead of Wanninkhof (1992) (Rutgersson et al., 2008). In coastal areas the uncertainty is even higher and only few studies have focused on determining transfer velocity for the coastal waters and even fewer on estuaries (Borges et al., 2004;Rutgersson et al., 2008). The transfer velocity (k600) of CO2 in the inner estuary of Roskilde Fjord, Denmark was investigated using eddy covariance CO2 fluxes (ECM) and directly measured ΔpCO2 during May and June 2010. The data was strictly sorted to heighten the certainty of the results and the outcome was; DS1; using only ECM, and DS2; including the inertial dissipation method (IDM). The inner part of Roskilde Fjord showed to be a very biological active CO2 sink and preliminary results showed that the average k600 was more than 10 times higher than transfer velocities from similar studies of other coastal areas. The much higher transfer velocities were estimated to be caused by the greater fetch and shallower water in Roskilde Fjord, which indicated that turbulence in both air and water influence k600. The wind speed parameterization of k600 using DS1 showed some scatter but when including IDM the r2 of DS2 reached 0.93 with an exponential parameterization, where U10 was based on the Businger-Dyer relationships using friction velocity and atmospheric stability. This indicates that some of the uncertainties coupled with CO2 fluxes calculated by the ECM are removed when including the IDM.

Geochemistry of surface sediments from the fjords of Northern Chilean Patagonia (44-47°S): Spatial variability and implications for paleoclimate reconstructions

NASA Astrophysics Data System (ADS)

Bertrand, Sébastien; Hughen, Konrad A.; Sepúlveda, Julio; Pantoja, Silvio

2012-01-01

The Patagonian fjords have a clear potential to provide high-resolution sedimentary and geochemical records of past climate and environmental change in the Southern Andes. To improve our ability to interpret these proxy records, we investigated the processes that control fjord sediment inorganic geochemistry through a geochemical, mineralogical and sedimentological analysis of surface sediment samples from the fjords of Northern Chilean Patagonia. A simple Terrestrial Index based on measurements of salinity and Fraction of Terrestrial Carbon was used to estimate the terrestrial input/river discharge at each site. Our results demonstrate that, under the cold climate conditions of Patagonia, chemical weathering is weak and the inorganic geochemical composition of the fjord sediments is primarily controlled by hydrodynamic mineralogical sorting, i.e., the intensity of river discharge. Our results suggest that the distribution of Fe, Ti and Zr in surface sediments is controlled by their association with heavy and/or coarse minerals, whereas Al is independent of hydrodynamic processes. The elemental ratios Fe/Al, Ti/Al and Zr/Al are therefore well suited for estimating changes in the energy of terrestrial sediment supply into the fjords through time. Zr/Al is particularly sensitive in proximal environments, while Fe/Al is most useful in the outer fjords and on the continental margin. In the most proximal environments, however, Fe/Al is inversely related to hydrodynamic conditions. Caution should therefore be exercised when interpreting Fe/Al ratios in terms of past river discharge. The application of these proxies to long sediment cores from Quitralco fjord and Golfo Elefantes validates our interpretations. Our results also emphasize the need to measure Al-based elemental ratios at high precision, which can be achieved using simultaneous acquisition ICP-AES technology. This study therefore constitutes a strong basis for the interpretation of sedimentary records from the Chilean Fjords.

Modern Deposition Rates and Patterns of Carbon Burial in Southern Fiordland, New Zealand

NASA Astrophysics Data System (ADS)

Ramirez, M. T.; Allison, M. A.; Vetter, L.; Cui, X.; Bianchi, T. S.; Smith, R. W.; Savage, C.; Schüller, S.

2016-02-01

Fjords have been recognized as a hotspot of organic carbon burial, as they accumulate a disproportionate quantity of organic carbon given their areal extent in comparison to other marine settings. However, organic carbon is buried in context with other biogenic and mineral sediments, so localized sedimentation processes play a critical role in determining rates of organic carbon burial. Therefore, it is important to assess the local sources and processes responsible for depositing inorganic sediment as a control on the burial of organic carbon. Here we evaluate three fjords in southern New Zealand that are not glaciated, with a sedimentary system that is dominantly controlled by terrigenous input at fjord heads, reworking of sediments over fjord-mouth sills, and landslide events from the steep fjord walls. Sediment cores were collected throughout the three southernmost fjord systems of Fiordland, New Zealand, and analyzed to determine sedimentary fabric, mass accumulation rates, and organic carbon content. Sediment mass accumulation rates from 210Pb geochronology range up to 500 mg/cm2/yr in proximal and distal areas of the fjords, with lower rates (below 200 mg/cm2/yr) in medial reaches, where terrestrial and marine sediment input is minimal. X-radiographs and 210Pb downcore activity trends show evidence of both mass wasting and surface-sediment bioturbation operating throughout the fjords. Percent organic carbon displays a negative correlation with mass accumulation rate and thickness of the sediment surface mixed layer. Rates of organic carbon accumulation ranged from 3.97 to 21.59 mg/cm2/yr, with a mean of 13.41 mg/cm2/yr. Organic carbon accumulation rates are dependent on the sediment accumulation rate and the percent organic carbon of the sediment. Our results highlight the importance of spatial variability in sedimentation processes and rates within fjords when evaluating organic carbon burial in these systems.

Retarded deglaciation of north-Spitsbergen fjords during the last glacial - an example of bathymetric controls on the dynamics of retreating glaciers

NASA Astrophysics Data System (ADS)

Forwick, M.; Vorren, T. O.; Hass, H.; Vogt, C. M.

2012-12-01

North and west Spitsbergen fjords acted as pathways for fast-flowing ice streams during the last glacial (e.g. Ottesen et al., 2005). The deglaciation of west Spitsbergen fjords occurred stepwise and the ice retreat terminated around 11,200 cal. years BP (calendar years before the present; e.g. Forwick & Vorren, 2009, 2011, and references therein; Baeten et al., 2010). However, the deglaciation dynamics and chronology of north Spitsbergen fjords still remain poorly understood. We present swath-bathymetry, high-resolution seismic data and two sediment cores from the approx. 110 km long, N-S oriented Wijdefjorden-Austfjorden fjord system, the largest fjord system on northern Spitsbergen. The data indicate that - as in the fjords on west Spitsbergen - multiple halts and/or readvances interrupted the retreat of the ice front during the final phase of the last glacial. However, even though the study area and several west Spitsbergen fjords are fed by the same glacier source (the ice field Lomonosovfonna), the final deglaciation of Wijdefjorden-Austfjorden took place after 9300 cal. years BP, i.e. at least approx. 2000 years later than in the west. We assume that the retarded deglaciation in the north is mainly related to the fjord bathymetry, i.e. a more than 35 km wide and up to 60 m high area in the central parts of the study area (approx. 45 km beyond the present fjord head) that acted as pinning point for the grounded glacier. Multiple, relatively large and partly stacked moraine ridges and sediment wedges are suggested to reflected that the ice front retreated slowly across this shallow area and that repeated readvances interrupted this retreat. The absence of larger sediment wedges in the deeper parts between the shallow area and the fjord head may indicate that the final retreat occurred relatively rapid. References: Baeten, N.J., Forwick, M., Vogt, C. & Vorren, T.O., 2010. Late Weichselian and Holocene sedimentary environments and glacial activity in Billefjorden, Svalbard. In: Howe, J.A., Austin, W.E.N, Forwick, M. & Paetzel, M. (eds.): Fjord Systems and Archives. Geological Society, London, Special Publication, 344, 207-223. Forwick, M. & Vorren, T.O., 2009. Late Weichselian and Holocene sedimentary environments and ice rafting in Isfjorden, Spitsbergen. Palaeogeography, Palaeoclimatology, Palaeoecology 280, 258-274. Forwick, M. & Vorren, T.O., 2011. Stratigraphy and deglaciation of the Isfjorden area, Spitsbergen. Norwegian Journal of Geology 90, 163-179. Ottesen, D., Dowdeswell, J.A., Rise, L., 2005. Submarine landforms and the reconstruction of fast-flowing ice streams within a large Quaternary ice sheet: The 2500-km-long Norwegian-Svalbard margin (57°-80°N). Geological Society of America Bulletin 117, 1033-1050.

High-resolution, multi-proxy characterization of the event deposit generated by the catastrophic events associated with the Mw 6.2 earthquake of 21 April 2007 in Aysén fjord (Chile)

NASA Astrophysics Data System (ADS)

De Batist, M. A.; Van Daele, M. E.; Cnudde, V.; Duyck, P.; Tjallingii, R. H.; Pino, M.; Urrutia, R.

2012-12-01

In 2007, a seismic swarm with more than 7000 recorded earthquakes affected the region around Aysén fjord, Chile (45°25'S). The series of seismic events reached a maximum on 21 April 2007, with an Mw 6.2 earthquake. Intensities as high as VIII to IX on the Modified Mercalli scale were reported around the epicenter. Multiple debris flows, rock slides and rock avalanches were triggered along the fjord's coastline, and several of these caused impact waves or tsunamis with wave heights of up to 6 m, which inundated the fjord shorelines and caused heavy damage and 10 casualties. In order to characterize in detail the imprint left by this series of catastrophic events in the sedimentary record of the fjord, we conducted a multi-disciplinary survey of the inner fjord region in December 2009. Multibeam bathymetry and high-resolution reflection seismic data reveal that large parts of the fjord basin floor, mostly at the foot of the fjord's steep underwater slopes, are covered by recent mass-wasting deposits or consist of mass-wasting-induced deformed basin-plain sediments. A series of short sediment cores collected throughout the inner fjord contain also the more distal deposits of this significant basin-wide mass-wasting event. By combining classical sedimentological techniques (i.e. grain-size analysis, LOI and magnetic susceptibility measurements, all at high resolution) with X-ray CT scanning and XRF scanning we were able to demonstrate that the event deposits encountered in the cores have a very complex signature and actually consist of a succession of several sub-deposits, comprising distal mass-flow deposits from different source areas (as evidenced by XRF-derived geochemical provenance indications) and with a different flow direction (as evidenced by CT-derived 3D flow-direction indications, such as imbricated rip-up mud clasts, cross and convolute laminations) and tsunami- or seiche-generated deposits. This allowed us to reconstruct the succession of sedimentary events that affected the inner fjord region and got imprinted in the fjord's sedimentary record. The improved characterization of such a complex event deposit may help to reconstruct the exact nature and basin-wide effects of past similar events (i.e. the seismic data show clear evidence of 3-4 similar prehistoric events) and to establish a reliable hazard assessment for the region.

Modeling of water masses exchange between Brepolen and the main fjord in the Western Svalbard fjord - Hornsund

NASA Astrophysics Data System (ADS)

Jakacki, Jaromir; Przyborska, Anna; Sunfjord, Arild; Albertsen, Jon; Białoskórski, Michał; Pliszka, Bartosz

2016-04-01

Hornsund is the southernmost fjord of the Svalbard archipelago island - Spitsbergen. It is under the influence of two main currents - the coastal Sørkapp Current (SC) carrying fresher and colder water masses from the Barents Sea and the West Spitsbergen Current (WSC), which is the branch of the Norwegian Atlantic Current (NwAC) and carries warm and salty waters from the North Atlantic. The main local forcing, which is tidal motion, brings shelf waters into the central fjord basin and then the transformed masses are carried into the easternmost part of the fjord, Brepolen. For the purpose of studying circulation and water exchange in this area a three-dimensional hydrodynamic model has been implemented and validated. The model is based on MIKE by DHI product and covers the Hornsund fjord with the shelf area, which is the fjord foreground. It is sigma a coordinate model (in our case 35 vertical levels) with variable horizontal resolution (mesh grid). The smallest cell has a horizontal dimension less than one hundred meters and the largest cells about 5 km. In spite of model limitations, the model reproduces the main circulation and water pathways in the Brepolen area. Seasonal and annual volume, heat and salt exchanges have been also estimated. The influence of freshwater discharge on shelf-fjord exchange will be also analyzed. The model results allow to study full horizontal and vertical fields of physical parameters (temperature, salinity, sea level variations and currents). The model integration covers only years 2005-2010 and the presented results will be based on this simulation. The project has been financed from the funds of the Leading National Research Centre (KNOW) received by the Centre for Polar Studies for the period 2014-2018

Sediment thicknesses and holocene glacial marine sedimentation rates in three east Greenland fjords (ca. 68°N)

USGS Publications Warehouse

Andrews, J.T.; Milliman, John D.; Jennings, A.E.; Rynes, N.; Dwyer, J.

1994-01-01

We compared measured and estimated sediment budgets in heavily glaciated fjords in East Greenland. Mass balance calculations and regional glacio-climatic conditions suggest that the sediment flux to the seafloor in Kangerdlugssuaq and Nansen fjords should be dominated by iceberg rafting and not by the rain-out of suspended particulates in meltwater, as the glacier calving flux is estimated at 15 and $2 km^{3}/yr$, compared to meltwater volumes of 4.4 and $1.7 km^{3}/yr$, respectively. Gravity cores in the three fjords indicate that the uppermost 1-2.5 m of sediment consists of diamictons or fine-grained laminated muds. AMS radiocarbon dates on calcareous foramininfera or shells (16 total) indicate sedimentation rates of 110 to 340 cm/ka within the fjords over the last 1 ka, and 10-20 cm/ka during the Holecene on the inner and middle shelf. Annual sediment discharge is around $0.67 \\times 10^{6}$ tonnes/yr within the Kangerdlugssuaq Fjord and Trough system, which translates into an average basin-wide rate of denudation of 0.01 mm/yr (0.01 m/ka). Air gun and deep-towed (Huntec) seismic profiling was carried out in Kangerdlugssuaq and Nansen fjords, East Greenland, and showed that sediment fills averaged 500 and 350 m respectively; they consist primarily of acoustically stratified sediments. If the sediment fills are entirely Holocene in age then the required average sediment accumulation rates of 35-50 m/ka are an order of magnitude larger than the $^{14}C $controlled rates of the last 1-2 ka. This raises the possibility that fjord sediments may be by-passed and not always recycled during glacial advances; this will affect sedimentation rates on adjacent shelves and deep-sea areas during successive glaciations

Glacial meltwater influences on plankton community structure and the importance of top-down control (of primary production) in a NE Greenland fjord

NASA Astrophysics Data System (ADS)

Arendt, Kristine Engel; Agersted, Mette Dalgaard; Sejr, Mikael Kristian; Juul-Pedersen, Thomas

2016-12-01

Freshwater runoff from the Greenland Ice Sheet (GIS) can be an important driver influencing plankton community structure in Greenland fjords. In the present study, we describe physical, taxonomic and functional differences in the plankton community in Young Sound, a NE Greenland fjord, from the inner fjord close to the GIS towards the coastal region in late summer. The fjord is influenced by runoff from land-terminating glaciers that separated the surface layer from cold underlying waters. The highest chlorophyll a concentration (<2.5 μg l-1) was found in the coastal region at 20-50 m depth. The most profound difference in the mesozooplankton community structure along the section was seen in the abundance of the copepods Microcalanus spp., which were present in the coastal region in the upper 100 m, and Pseudocalanus spp., which only occurred in the surface layers and mainly in the inner part of the fjord. In addition to this, both species have been observed to change in abundance within the last decade. Calanus spp. copepods made up > 74.9% of the total copepod biomass at all stations, and their grazing impact was the highest among the copepod groups. Copepod grazing impact on the phytoplankton standing stock, however, was exceeded by microzooplankton grazing, investigated by dilution experiments, with the highest grazing impact on the phytoplankton standing stock of 63% d-1 in the inner part of the fjord. In spite of high phytoplankton instantaneous growth rates at the innermost fjord station, proto-zooplankton was capable of controlling the phytoplankton production. The study showed functional differences within the system and provides indications of how dynamic the coastal ecosystem of Greenland can be.

Circulation and fjord-shelf exchange during the ice-covered period in Young Sound-Tyrolerfjord, Northeast Greenland (74°N)

NASA Astrophysics Data System (ADS)

Boone, W.; Rysgaard, S.; Kirillov, S.; Dmitrenko, I.; Bendtsen, J.; Mortensen, J.; Meire, L.; Petrusevich, V.; Barber, D. G.

2017-07-01

Fjords around Greenland connect the Greenland Ice Sheet to the ocean and their hydrography and circulation are determined by the interplay between atmospheric forcing, runoff, topography, fjord-shelf exchange, tides, waves, and seasonal growth and melt of sea ice. Limited knowledge exists on circulation in high-Arctic fjords, particularly those not impacted by tidewater glaciers, and especially during winter, when they are covered with sea-ice and freshwater input is low. Here, we present and analyze seasonal observations of circulation, hydrography and cross-sill exchange of the Young Sound-Tyrolerfjord system (74°N) in Northeast Greenland. Distinct seasonal circulation phases are identified and related to polynya activity, meltwater and inflow of coastal water masses. Renewal of basin water in the fjord is a relatively slow process that modifies the fjord water masses on a seasonal timescale. By the end of winter, there is two-layer circulation, with outflow in the upper 45 m and inflow extending down to approximately 150 m. Tidal analysis showed that tidal currents above the sill were almost barotropic and dominated by the M2 tidal constituent (0.26 m s-1), and that residual currents (∼0.02 m s-1) were relatively small during the ice-covered period. Tidal pumping, a tidally driven fjord-shelf exchange mechanism, drives a salt flux that is estimated to range between 145 kg s-1 and 603 kg s-1. Extrapolation of these values over the ice-covered period indicates that tidal pumping is likely a major source of dense water and driver of fjord circulation during the ice-covered period.

Ecological overview of Kenai Fjords National Park

USGS Publications Warehouse

Spencer, Page; Irvine, Gail V.

2004-01-01

The major drivers of Kenai Fjords ecosystems are tectonics and climate. In this overview, we describe how these forces have contributed to the shaping of the lands and ecosystems of Kenai Fjords.Physically, the park is comprised of several distinct components, set within a broader ecophysical framework that includes the Kenai Peninsula and coastal marine waters and islands. Squeezed between the Gulf of Alaska and the Kenai Mountains, the coastal zone of the park is a narrow band of exposed headlands and deep fjords. The Harding Icefield caps the Kenai Mountains above the fjords with ice estimated to be 3,000 feet (1,000 m) thick (Figure 1). Although not included in the National Park Service jurisdiction, the park is ecologically linked to the offshore marine ecosystem, and the embedded offshore islands, most of which are part of the Alaska Maritime National Wildlife Refuge, managed by the U.S. Fish and Wildlife Service.

The impact of glacier geometry on meltwater plume structure and submarine melt in Greenland fjords

NASA Astrophysics Data System (ADS)

Carroll, D.; Sutherland, D. A.; Hudson, B.; Moon, T.; Catania, G. A.; Shroyer, E. L.; Nash, J. D.; Bartholomaus, T. C.; Felikson, D.; Stearns, L. A.; Noël, B. P. Y.; Broeke, M. R.

2016-09-01

Meltwater from the Greenland Ice Sheet often drains subglacially into fjords, driving upwelling plumes at glacier termini. Ocean models and observations of submarine termini suggest that plumes enhance melt and undercutting, leading to calving and potential glacier destabilization. Here we systematically evaluate how simulated plume structure and submarine melt during summer months depends on realistic ranges of subglacial discharge, glacier depth, and ocean stratification from 12 Greenland fjords. Our results show that grounding line depth is a strong control on plume-induced submarine melt: deep glaciers produce warm, salty subsurface plumes that undercut termini, and shallow glaciers produce cold, fresh surface-trapped plumes that can overcut termini. Due to sustained upwelling velocities, plumes in cold, shallow fjords can induce equivalent depth-averaged melt rates compared to warm, deep fjords. These results detail a direct ocean-ice feedback that can affect the Greenland Ice Sheet.

Field Survey of the 17 June 2017 Landslide and Tsunami in Karrat Fjord, Greenland

NASA Astrophysics Data System (ADS)

Fritz, H. M.; Giachetti, T.; Anderson, S.; Gauthier, D.

2017-12-01

On 17 June 2017 a massive landslide generated tsunami impacted Karrat Fjord and the Uummannaq fjord system located some 280 km north of Ilulissat in western Greenland. The eastern of two easily recognized landslides detached completely and fell approximately 1 km to sea level, before plunging into the Karrat Fjord and generating a tsunami within the fjord system. The landslide generated tsunami washed 4 victims and several houses into the fjord at Nuugaatsiaq, about 30 km west of the landslide. Eyewitnesses at Nuugaatsiaq and Illorsuit recorded the tsunami inundation on videos. The active western landslide features a back scarp and large cracks, and therefore remains a threat in Karrat Fjord. The villages of Nuugaatsiaq and Illorsuit remain evacuated. The Geotechnical Extreme Events Reconnaissance (GEER) survey team deployed to Greenland from July 6 to 9, 2017. The reconnaissance on July 8 involved approximately 800 km of helicopter flight and landings in several key locations. The survey focused on the landslides and coastlines within 30 km of the landslide in either fjord direction. The aerial reconnaissance collected high quality oblique aerial photogrammetry (OAP) of the landslide, scarp, and debris avalanche track. The 3D model of the landslide provides the ability to study the morphology of the slope on July 8, it provides a baseline model for future surveys, and it can be used to compare to earlier imagery to estimate what happened on June 17. Change detection using prior satellite imagery indicates an approximate 55 million m3 total landslide volume of which 45 million m3 plunged into the fjord from elevations up to 1200 m above the water surface. The ground based tsunami survey documented flow depths, runup heights, inundation distances, sediment deposition, damage patterns at various scales, performance of the man-made infrastructure, and impact on the natural and glacial environment. Perishable high-water marks include changes in vegetation and damage to roots, deposits and scour of soil and rock, stranded icebergs, as well as damage to homes and infrastructure. The tsunami runup heights exceeded 90 m laterally to the west of the landslide and 50 m across the 6 km wide fjord. The Greenland landslide generated tsunami highlights coastal hazards to communities not commonly exposed to earthquake generated tsunamis.

Fiches pratiques: Pour ne pas perdre le nord...; Mariage a la russe; Un pari sur Paris; Une tenebreuse affaire (Practical Ideas: Don't Lose Your Bearings...; Marriage Russian Style; A Bet on Paris; A Gloomy Affair).

ERIC Educational Resources Information Center

Rocca, Carla; And Others

1990-01-01

Four ideas for language classroom activities are presented, including a counting and calculation game, an exercise for developing familiarity with the parts and style of a newspaper article, an activity to help adolescents anticipating travel in a French city, and analysis of the textual structure of a current events circle. (MSE)

Main results of the 2012 joint Norwegian-Russian expedition to the dumping sites of the nuclear submarine K-27 and solid radioactive waste in Stepovogo Fjord, Novaya Zemlya.

PubMed

Gwynn, Justin P; Nikitin, Aleksander; Shershakov, Viacheslav; Heldal, Hilde Elise; Lind, Bjørn; Teien, Hans-Christian; Lind, Ole Christian; Sidhu, Rajdeep Singh; Bakke, Gunnar; Kazennov, Alexey; Grishin, Denis; Fedorova, Anastasia; Blinova, Oxana; Sværen, Ingrid; Lee Liebig, Penny; Salbu, Brit; Wendell, Cato Christian; Strålberg, Elisabeth; Valetova, Nailja; Petrenko, Galina; Katrich, Ivan; Logoyda, Igor; Osvath, Iolanda; Levy, Isabelle; Bartocci, Jean; Pham, Mai Khanh; Sam, Adam; Nies, Hartmut; Rudjord, Anne Liv

2016-01-01

This paper reports the main results of the 2012 joint Norwegian-Russian expedition to investigate the radioecological situation of the Stepovogo Fjord on the eastern coast of Novaya Zemlya, where the nuclear submarine K-27 and solid radioactive waste was dumped. Based on in situ gamma measurements and the analysis of seawater and sediment samples taken around the submarine, there was no indication of any leakage from the reactor units of K-27. With regard to the radioecological status of Stepovogo Fjord, activity concentrations of all radionuclides in seawater, sediment and biota in 2012 were in general lower than reported from the previous investigations in the 1990s. However in 2012, the activity concentrations of (137)Cs and, to a lesser extent, those of (90)Sr remained elevated in bottom water from the inner part of Stepovogo Fjord compared with surface water and the outer part of Stepovogo Fjord. Deviations from expected (238)Pu/(239,240)Pu activity ratios and (240)Pu/(239)Pu atom ratios in some sediment samples from the inner part of Stepovogo Fjord observed in this study and earlier studies may indicate the possibility of leakages from dumped waste from different nuclear sources. Although the current environmental levels of radionuclides in Stepovogo Fjord are not of immediate cause for concern, further monitoring of the situation is warranted. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ocean-Glaciers Interactions in the Southern Svalbard Fjord, Hornsund.

NASA Astrophysics Data System (ADS)

Walczowski, W.; Beszczynska-Moeller, A.; Prominska, A.; Kruss, A.

2017-12-01

The Arctic fjords constitute a link between the ocean and land, therefore there are highly vulnerable to warming and are expected to exhibit the earliest environmental changes resulting from anthropogenic impacts on climate. In the Arctic, the inshore boundary of a fjord system is usually dominated by tidewater glaciers while its offshore boundary is strongly influenced by warm oceanic waters. Improved understanding of the fjord-ocean exchange and processes within Arctic fjords is of a highest importance because their response to atmospheric, oceanic and glacial variability provides a key to understand the past and to forecast the future of the high latitude glaciers and Arctic climate. The results of field measurements in the Hornsund fjord (southern Svalbard), collected under the Polish-Norwegian projects GLAERE and AWAKE-2, will be presented. Interannual variability of warm Atlantic water entering the fjord, seasonal changes of ocean properties in the glacier bays and the structure of the water column in the vicinity of the glacier termination will be addressed. Direct contact of warm oceanic water with a glacier's wall causes submarine melting, undercutting and glacier calving. Turbulent plumes of subglacial meltwater constitute an important mechanism of heat transfer and also influence a glacier retreat. However our understanding of these processes is limited due to problems with obtaining in situ data close to the glacier wall. Therefore special attention will be paid to observations of the underwater parts of Hornsund glaciers and new measurements of water column fine structure and mixing in the turbulent meltwater plumes.

Arctic Sediment Transport from Land to Sea - An Integrated Study of Coastal - Marine Processes and Deposits in Dicksonfjorden, Svalbard

NASA Astrophysics Data System (ADS)

Jensen, M.; Choi, K.; Forwick, M.; Howe, J. A.; Husum, K.; Korsun, S.; Maat, D.; Nam, S. I.

2016-12-01

Valleys and fjords are the key transport and storage systems for sediments and biogeochemical elements from high arctic landscapes to the ocean. Sediment and nutrient fluxes are important for the biochemical cycle in the fjords and eventually in the ocean, and are important input data to earth system models. At present, high latitude systems are underrepresented in such models (Russell, 2014). Dicksonfjorden is a fjord in the larger Isfjorden system, Central Spitsbergen, Svalbard. It has no direct glacial input, in contrast to fjords affected by tidewater glaciers. The sediment supply is very high and the inner fjord receives sediment from a tide-influenced delta. This study is part of a multidisciplinary project aiming at mapping and quantifying sediment types and dispersal patterns in present Arctic valley - fjord systems and is the first comprehensive study of the depositional system in Dicksonfjorden. The first field campaign took place in summer 2016, when detailed mapping of the tidal delta and the sea floor in the inner fjord, coring onshore and offshore and sampling for foraminifera, nutrients and microbial abundances were performed. The surface mapping is based on high-resolution drone images, which will be processed to a high-resolution digital elevation model, and the bathymetry and sediment distribution data from the sea floor has been collected with a Gavia Offshore Surveyor AUV, providing high-resolution bathymetry and backscatter data of the seabed. Core transects from the delta surface will be described and compared to marine cores from the fjord basin retrieved from R/V Helmer Hanssen. Sediment accumulation rates will be assessed from 210Pb and 137Cs radionuclides. Preliminary results on the physical and chemical characteristics of the sedimentation system in inner Dicksonfjorden will be presented and implications for the fjord ecosystem will be discussed. References Russell , J.L., 2014. Control on the Latitudinal distribution of climate processes: Results from Earth System Model simulations. AAPG/SEPM Hedberg Research Conference "Latitudinal controls on stratigraphic models and sedimentary concepts, Banff, Alberta, Canada, September 28 - October 1, 2014, Abstract volume, 10-11.

Climate related trends and meteorological conditions in European Arctic region - Porsanger fjord, Norway

NASA Astrophysics Data System (ADS)

Cieszyńska, Agata; Stramska, Małgorzata

2017-04-01

Climate change has significant effect on the Arctic environment, where global trends are amplified. In this study, we have focused on the Porsanger fjord, located in European Arctic in the coastal region of the Barents Sea. We have analyzed climate related trends and meteorological condititions in the area of interest. Meteorological data included wind speed and direction, air temperature (AT) and precipitation from Era-Interim reanalysis (1986-2015) and local observations (1996-2015) from Lakselv (L, fjord's head area) and Honningsvaag (H - fjord's exit area). Our results confirm that this region is undergoing climate change related warming, which is indicated by rising air temperatures. Based on long-term reanalysis data, estimated trends for air temperature (AT) in Porsanger fjord are: 0.0536 °C year-1 at fjord's exit and 0.0428 °C year-1 at fjord's head. The results show that climate change does not seem to have a significant effect on long-term changes of wind speed and precipitation in the Porsanger fjord. Statistical analysis underlined significant spatial variability of meteorological conditions inside the fjord. For example, there are large differences in the annual cycle of AT with monthly mean January and July values of -8.4 and 12.6 °C in L and -2.5 and 10.1 °C in H. Dominant wind directions in Lakselv are S and SSE, while in Honningsvaag S and SSW directions prevail. Strong wind events (above 12 m s-1) are more frequent in H than in L. Annual cycle is characterized by stronger winds in winter and seasonality of wind direction. Precipitation for a given location can change by about 50% between years and varies spatially. Synoptic scale and within day variability are extremely intense in the area of interest. Air temperature and wind speed and direction can change dramatically in hours. In addition, regular patterns of the daily cycle of AT have different intensity in L and H. It is interesting to note that in spring/summer season, the daily cycle of air temperature difference between L and H is also strong and has an influence on winds. Estimates of land-originated water discharge (derived from the E-Hype model) show seasonal cycle with the maximum runoff in late spring/early summer. The main features of climate related trends and the effects of oceanic/continental interactions, presented in this study, shape the environment of the fjord and are possible to be analogous in other Norwegian fjords with comparable geographical location. This work was funded by the Norway Grants (NCBR contract No. 201985, project NORDFLUX). Partial support for MS comes from the Institute of Oceanology (IO PAN).

Bathymetry data reveal glaciers vulnerable to ice-ocean interaction in Uummannaq and Vaigat glacial fjords, west Greenland

NASA Astrophysics Data System (ADS)

Rignot, E.; Fenty, I.; Xu, Y.; Cai, C.; Velicogna, I.; Cofaigh, C. Ó.; Dowdeswell, J. A.; Weinrebe, W.; Catania, G.; Duncan, D.

2016-03-01

Marine-terminating glaciers play a critical role in controlling Greenland's ice sheet mass balance. Their frontal margins interact vigorously with the ocean, but our understanding of this interaction is limited, in part, by a lack of bathymetry data. Here we present a multibeam echo sounding survey of 14 glacial fjords in the Uummannaq and Vaigat fjords, west Greenland, which extends from the continental shelf to the glacier fronts. The data reveal valleys with shallow sills, overdeepenings (>1300 m) from glacial erosion, and seafloor depths 100-1000 m deeper than in existing charts. Where fjords are deep enough, we detect the pervasive presence of warm, salty Atlantic Water (AW) (>2.5°C) with high melt potential, but we also find numerous glaciers grounded on shallow (<200 m) sills, standing in cold (<1°C) waters in otherwise deep fjords, i.e., with reduced melt potential. Bathymetric observations extending to the glacier fronts are critical to understand the glacier evolution.

Resolving bathymetry from airborne gravity along Greenland fjords

USGS Publications Warehouse

Boghosian, Alexandra; Tinto, Kirsty; Cochran, James R.; Porter, David; Elieff, Stefan; Burton, Bethany L.; Bell, Robin E.

2015-01-01

Recent glacier mass loss in Greenland has been attributed to encroaching warming waters, but knowledge of fjord bathymetry is required to investigate this mechanism. The bathymetry in many Greenland fjords is unmapped and difficult to measure. From 2010 to 2012, National Aeronautics and Space Administration's Operation IceBridge collected a unique set of airborne gravity, magnetic, radar, and lidar data along the major outlet glaciers and fjords in Greenland. We applied a consistent technique using the IceBridge gravity data to create 90 bathymetric profiles along 54 Greenland fjords. We also used this technique to recover subice topography where warm or crevassed ice prevents the radar system from imaging the bed. Here we discuss our methodology, basic assumptions and error analysis. We present the new bathymetry data and discuss observations in six major regions of Greenland covered by IceBridge. The gravity models provide a total of 1950 line kilometers of bathymetry, 875 line kilometers of subice topography, and 12 new grounding line depths.

Pyroclastic Eruption Boosts Organic Carbon Fluxes Into Patagonian Fjords

NASA Astrophysics Data System (ADS)

Mohr, Christian H.; Korup, Oliver; Ulloa, Héctor; Iroumé, Andrés.

2017-11-01

Fjords and old-growth forests store large amounts of organic carbon. Yet the role of episodic disturbances, particularly volcanic eruptions, in mobilizing organic carbon in fjord landscapes covered by temperate rainforests remains poorly quantified. To this end, we estimated how much wood and soils were flushed to nearby fjords following the 2008 eruption of Chaitén volcano in south-central Chile, where pyroclastic sediments covered >12 km2 of pristine temperate rainforest. Field-based surveys of forest biomass, soil organic content, and dead wood transport reveal that the reworking of pyroclastic sediments delivered 66,500 + 14,600/-14,500 tC of large wood to two rivers entering the nearby Patagonian fjords in less than a decade. A similar volume of wood remains in dead tree stands and buried beneath pyroclastic deposits ( 79,900 + 21,100/-16,900 tC) or stored in active river channels (5,900-10,600 tC). We estimate that bank erosion mobilized 132,300+21,700/-30,600 tC of floodplain forest soil. Eroded and reworked forest soils have been accreting on coastal river deltas at >5 mm yr-1 since the eruption. While much of the large wood is transported out of the fjord by long-shore drift, the finer fraction from eroded forest soils is likely to be buried in the fjords. We conclude that the organic carbon fluxes boosted by rivers adjusting to high pyroclastic sediment loads may remain elevated for up to a decade and that Patagonian temperate rainforests disturbed by excessive loads of pyroclastic debris can be episodic short-lived carbon sources.

Preliminary validation of WRF model in two Arctic fjords, Hornsund and Porsanger

NASA Astrophysics Data System (ADS)

Aniskiewicz, Paulina; Stramska, Małgorzata

2017-04-01

Our research is focused on development of efficient modeling system for arctic fjords. This tool should include high-resolution meteorological data derived using downscaling approach. In this presentation we have focused on modeling, with high spatial resolution, of the meteorological conditions in two Arctic fjords: Hornsund (H), located in the western part of Svalbard archipelago and Porsanger (P) located in the coastal waters of the Barents Sea. The atmospheric downscaling is based on The Weather Research and Forecasting Model (WRF, www.wrf-model.org) with polar stereographic projection. We have created two parent domains with grid point distances of about 3.2 km (P) and 3.0 km (H) and with nested domains (almost 5 times higher resolution than parent domains). We tested what is the impact of the spatial resolution of the model on derived meteorological quantities. For both fjords the input topography data resolution is 30 sec. To validate the results we have used meteorological data from the Norwegian Meteorological Institute for stations Lakselv (L) and Honningsvåg (Ho) located in the inner and outer parts of the Porsanger fjord as well as from station in the outer part of the Hornsund fjord. We have estimated coefficients of determination (r2), statistical errors (St) and systematic errors (Sy) between measured and modelled air temperature and wind speed at each station. This approach will allow us to create high resolution spatially variable meteorological fields that will serve as forcing for numerical models of the fjords. We will investigate the role of different meteorological quantities (e. g. wind, solar insolation, precipitation) on hydrohraphic processes in fjords. The project has been financed from the funds of the Leading National Research Centre (KNOW) received by the Centre for Polar Studies for the period 2014-2018. This work was also funded by the Norway Grants (NCBR contract No. 201985, project NORDFLUX). Partial support comes from the Institute of Oceanology (IO PAN).

Measured and Modelled Tidal Circulation Under Ice Covered Van Mijenforden

NASA Astrophysics Data System (ADS)

Nilsen, F.

The observation and model area Van Mijenfjorden is situated at the west coast of Spits- bergen. An area of 533 km2 makes it the second largest fjord on Spitsbergen and the distance from the head to the mouth of the fjord is approximately 70 km. An 8.5km long and 1km wide island, Akseløya, is lying across the fjord mouth and blocking exchanges between the fjord and the coastal water masses outside. The sound Aksel- sundet on the northern side of the island is 1km wide and has a sill at 34m depth. On the southern side an islet, Mariaholmen, is between two sounds that are 200m wide and 2m deep, and 500m wide and 12m deep. Strong tidal currents exist in these sounds. Van Mijenfjorden has special ice conditions in that Akseløya almost closes the fjord, and comparatively little ice comes in from west. On the other hand, there are periods with fast ice in the fjord inside Akseløya longer than in other places, as the sea waves have little chance to break up fast ice here, or delay ice formation in autumn/winter. Van Mijenfjorden is often separated into two basins by a sill at 30m depth. The inner basin is typical 5km wide and has a maximum depth of 80m, while the outer basin is on average 10 km wide and has a maximum depth of 115m. Hydrographic measurements have been conducted since 1958 and up to the present. Through the last decade, The University Courses on Svalbard (UNIS) has used this fjord as a laboratory for their student excursions, in connection to courses in air-ice- ocean interaction and master programs, and build up an oceanographic data base. In this work, focus is put on the wintertime situation and the circulation under an ice covered fjord. Measurements show a mean cyclonic circulation pattern in the outer basin with tidal oscillation (mainly M2) superposed on this mean vector. A three- dimensional sigma layered numerical model called Bergen Ocean Model (BOM) was used to simulate the circulation in Van Mijenfjorden with only tidal forcing. The four most pronounced tidal components were used to force the model area outside Ak- seløya. The calculated cyclonic circulation pattern fits the measurements, proving that the fjord circulation is controlled by tides in periods when the ice cover shade the fjord water masses from direct wind forcing.

Greenland elders and high school students offer perspectives on climate change and science

NASA Astrophysics Data System (ADS)

Showstack, Randy

2011-08-01

KANGERLUSSUAQ, GREENLAND—This small town in central western Greenland, which has a population of about 650 and a major airstrip dating from World War II, is a center for scientific research and a starting point for scientists working in the region and on Greenland's ice sheet to study climate change and other issues. The town, just north of the Arctic Circle, sits at the edge of the 190-kilometer-long Kangerlussuaq Fjord and straddles the Qinnguata Kuussua River estuary, whose source water is the Russell Glacier, about 20 kilometers to the east. Between Kanger—as some refer to the town—and the glacier, some Eskimo-Kalaallit elders held a traditional gathering last month and also offered their perspectives on climate change during an impromptu 14 July meeting with high school students and other visitors. The evening before that meeting, Ole Olsvig, Kurt Olsen, Avaruna Mathaeussen, and other high schoolers from Greenland were in a makeshift classroom at the back of a renovated former U.S. Army barracks in Kanger, which had served as a U.S. military base. The students, who said they care deeply about their traditional culture and also are very aware of recent changes in climate, were helping to make presentations about their summer science projects. A total of 16 high schoolers from Greenland, 3 from Denmark, and 5 from the United States were there, participating in Joint Science Education Project (JSEP) activities; JSEP is an international collaborative polar science education effort between Greenland, Denmark, and the United States that receives support from the U.S. National Science Foundation (NSF).

A fjord-glacier coupled system model

NASA Astrophysics Data System (ADS)

de Andrés, Eva; Otero, Jaime; Navarro, Francisco; Prominska, Agnieszka; Lapazaran, Javier; Walczowski, Waldemar

2017-04-01

With the aim of studying the processes occurring at the front of marine-terminating glaciers, we couple a fjord circulation model with a flowline glacier dynamics model, with subglacial discharge and calving, which allows the calculation of submarine melt and its influence on calving processes. For ocean modelling, we use a general circulation model, MITgcm, to simulate water circulation driven by both fjord conditions and subglacial discharge, and for calculating submarine melt rates at the glacier front. To constrain freshwater input to the fjord, we use estimations from European Arctic Reanalysis (EAR). To determine the optimal values for each run period, we perform a sensitivity analysis of the model to subglacial discharge variability, aimed to get the best fit of model results to observed temperature and salinity profiles in the fjord for each of these periods. Then, we establish initial and boundary fjord conditions, which we vary weekly-fortnightly, and calculate the submarine melt rate as a function of depth at the calving front. These data are entered into the glacier-flow model, Elmer/Ice, which has been added a crevasse-depth calving model, to estimate the glacier terminus position at a weekly time resolution. We focus our study on the Hansbreen Glacier-Hansbukta Fjord system, in Southern Spitsbergen, Svalbard, where a large set of data are available for both glacier and fjord. The bathymetry of the entire system has been determined from ground penetrating radar and sonar data. In the fjord we have got temperature and salinity data from CTDs (May to September, 2010-2014) and from a mooring (September to May, 2011-2012). For Hansbreen, we use glacier surface topography data from the SPIRIT DEM, surface mass balance from EAR, centre line glacier velocities from stake measurements (May 2005-April 2011), weekly terminus positions from time-lapse photos (Sept. 2009-Sept. 2011), and sea-ice concentrations from time-lapse photos and Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data. Results suggest submarine melt rates at Hansbreen terminus implying noticeable changes in the glacier front geometry, and hence the stress field, which favour the occurrence of calving events. In this way, submarine melt at the glacier front could be a first-order mechanism in determining the terminus position in late summer.

Benthic foraminiferal biogeography in NW European fjords: A baseline for assessing future change

NASA Astrophysics Data System (ADS)

Murray, John W.; Alve, Elisabeth

2016-11-01

The seaboard extending from northern Svalbard to Scotland is the only region of the world where fjords have been comprehensively studied for their live (stained) benthic foraminiferal faunas. These modern faunas provide essential baseline data for the interpretation of the postglacial and continuing environmental changes in those fjords and this is the first biogeographic synthesis. The data come from the surface sediment assemblages (mainly sampled in the 1990's) from all the available literature. Due to limited information of shallow water assemblages in the north, only the species occurrences in deeper water from below the halocline are considered. Amongst these, only "common species" species occurring in more than one fjord are included. There is a clear pattern of distribution with five groups of taxa: 5 widespread species found throughout the region; 53 species reaching their northern limit; 13 species reaching their southern limit; 11 deep-sea species; 1 recently introduced species. Although there is an abrupt change in temperature from Tanafjorden in northern Norway to Hornsund in southern Svalbard, the faunal change from N to S is progressive throughout the investigated region. The area of overlap of the northern and southern species corresponds with the previously recognised boundary between the Barents Sea Province and the Norwegian Coast Province based on shelf and upper slope invertebrate macrofaunal benthos and plankton. Temperature is the main abiotic control on the distributions. For the fjords which have shallow sills separating them from the open shelf it is likely that most of the foraminiferal colonisers of the deeper fjord basins are sourced from the shelf or slope via propagules. One species has recently been introduced from further south into the southern region probably through the discharge of ballast water from ships. The biodiversity of the pristine Svalbard fjords extends below what is considered to reflect acceptable ecological status for mainland Norway, illustrating the need to introduce new methods to determine possible deviations from the reference conditions as defined in the EU's Water Framework Directive (WFD; 2000/60/EC). Altogether 347 species have so far been recorded in Norwegian waters: 214 in fjords (60 above and 180 below the halocline of which 26 occur both above and below the halocline) and 266 on the shelf and slope (133 of which also occur in fjords).

Carbon Burial at the Land Ocean Interface: Climate vs Human Drivers

NASA Astrophysics Data System (ADS)

Bianchi, T. S.; Smeaton, C.; Cui, X.; Howe, J. A.; Austin, W.

2017-12-01

Fjords are connectors between the terrestrial and marine systems and are known as globally significant hotspots for the burial (Smith et al., 2014) and long-term storage (Smeaton et al., 2016) of carbon (C). The glacial geomorphology of fjords and their catchment results in the terrestrial and marine environments being strongly coupled more so than other estuary types. The clearest example of this is the terrestrial C subsidy to these sediment, it is estimated that globally 55-62% of C held in fjord sediments are terrestrially derived (Cui et al., 2016). Yet it is largely unknown how climatic and human forcing drives the transfer of terrestrial C to marine sediments. Here we, examine the role of late Holocene climate and human activity on the transfer of C from the terrestrial to marine environment along the North Atlantic Margin. Loch Sunart a Scottish fjord sits at the land ocean interface of the North Atlantic. The catchment of the fjord has been shown to be sensitive to local and regional climatic change (Gillibrand et al., 2005) and the fjord sediments have been able to record these changes in Climate (Cage and Austin, 2010). Using a long (22 m) sedimentary record we discuss our understanding of mid to late Holocene regional climate and its impact on terrestrial C transfer to the coastal ocean. Alongside this we examine the role of humans on the landscape and their impact on the transfer of terrestrial C on the coastal ocean. The results from this study will further our understanding of the long-term drivers of terrestrial C transfer to the coastal ocean. Potentially this research provides insights on future C transfers under a changing future climate allowing the importance of fjords as a climate regulation service to be reassessed.

Calculating Freshwater Input from Iceberg Melt in Greenlandic Fjords by Combining In Situ Observations of Iceberg Movement with High Resolution Satellite Imagery

NASA Astrophysics Data System (ADS)

Sulak, D. J.; Sutherland, D.; Stearns, L. A.; Hamilton, G. S.

2015-12-01

Understanding fjord circulation in Greenland's outlet glacial fjords is crucial to explaining recent temporal and spatial variability in glacier dynamics, as well as freshwater transport on the continental shelf. The fjords are commonly assumed to exhibit a plume driven circulation that draws in warmer and saltier Atlantic-origin water toward the glacier at depth. Freshwater input at glacier termini directly drives this circulation and significantly influences water column stratification, which indirectly feeds back on the plume driven circulation. Previous work has focused on freshwater inputs from surface runoff and submarine melting, but the contribution from iceberg melt, a potentially important freshwater source, has not been quantified. Here, we develop a new technique combining in situ observations of movement from iceberg-mounted GPS units with multispectral satellite imagery from Landsat 8. The combination of datasets allows us to examine the details of iceberg movement and quantify mean residence times in a given fjord. We then use common melt rate parameterizations to estimate freshwater input for a given iceberg, utilizing novel satellite-derived iceberg distributions to scale up to a fjord-wide freshwater contribution. We apply this technique to Rink Isbræ and Kangerlussuup Sermia in west Greenland, and Helheim Glacier in southeast Greenland. The analysis can be rapidly expanded to look at other systems as well as seasonal and interannual changes in how icebergs affect the circulation and stratification of Greenland's outlet glacial fjords. Ultimately, this work will lead to a more complete understanding of the wide range of factors that control the observed regional variability in Greenland's glaciers.

Observed Spatial and Temporal Variability of Subglacial Discharge-Driven Plumes in Greenland's Outlet Glacial Fjords

NASA Astrophysics Data System (ADS)

Sutherland, D.; Carroll, D.; Nash, J. D.; Shroyer, E.; Mickett, J.; Stearns, L. A.; Fried, M.; Bartholomaus, T.; Catania, G. A.

2015-12-01

Hydrographic and velocity observations in Greenland's outlet glacier fjords have revealed, unsurprisingly, a rich set of dynamics over a range of spatial and temporal scales. Through teasing apart the distinct processes that control circulation within these fjords, we are likely to better understand the impact of fjord circulation on modulating outlet glacier dynamics, and thus, changes in Greenland Ice Sheet mass balance. Here, we report on data from the summers of 2013-2015 in two neighboring fjords in the Uummannaq Bay region of west Greenland: Kangerlussuup Sermia (KS) and Rink Isbræ (RI). We find strong subglacial discharge driven plumes in both systems that evolve on synoptic and seasonal time scales, without the complicating presence of other circulation processes. The plumes both modify fjord water properties and respond to differences in ambient water properties, supporting the notion that a feedback exists between subglacial discharge plume circulation and water mass properties. This feedback between subglacial discharge and water properties potentially influences submarine melt rates at the glacier termini. Observed plume properties, including the vertical structure of velocity, and temperature and salinity anomalies, are compared favorably to model estimates. In KS, we find a near-surface intensified plume with high sediment content that slows and widens as it evolves downstream. In contrast, the plume in RI is entirely subsurface, ranging from 100-300 m depth at its core during summer, although it shows similar temperature, salinity, and optical backscatter signals to the KS plume. Importantly, the distinct vertical plume structures imprint on the overall water mass properties found in each fjord, raising the minimum temperatures by up to 1-2°C in the case of RI.

Biodiversity and abundance patterns of rock encrusting fauna in a temperate fjord.

PubMed

Kuklinski, Piotr

2013-01-01

Fjords are semi-enclosed systems often with usually strong physical and chemical gradients. These gradients provide the opportunity to test the influence of various physical and chemical factors on biodiversity. However study area of this investigation, Trondheimsfjord, is a large water body where especially salinity gradient along the fjord is not well pronounced. The goal of this study was to establish within a temperate fjord a baseline identifying encrusting fauna on rocks and determine the factors driving changes along the length of the fjord and changing depths. There was no trend in species composition change and increase or decrease in number of species, diversity and number of individuals along the fjord. This was likely due to the relative homogeneity of both substrate (rocks) and environmental parameters. Nevertheless, the influence of fresh water inflow in the vicinity of the river mouth was apparent by the presence of characteristic brackish-water species at these locations. Multidimensional scaling analysis revealed three separate assemblages: intertidal, shallow and deep subtidal (below 50 m). Intertidal assemblages were species poor (one to 11 species) but relatively abundant (six to 2374 indiv./m(2) of rocks). Number of individuals and biomass was highest in the shallow subtidal (2059-13,587 indiv./m(2) of rocks). Overall the highest species number (45) was recorded at 50 m depth which is probably result of low competition pressure yet still relatively high nutrient concentration in comparison to shallower locations. Environmental parameters (i.e., tidal currents, wave action, salinity) change more drastically with depth than along the fjord and these changes are the major driving forces in shaping encrusting assemblages in Trondheimsfjord. Copyright © 2013 Elsevier Ltd. All rights reserved.

Annual changes in Arctic fjord environment and modern benthic foraminiferal fauna: Evidence from Kongsfjorden, Svalbard

NASA Astrophysics Data System (ADS)

Jernas, Patrycja; Klitgaard-Kristensen, Dorthe; Husum, Katrine; Koç, Nalan; Tverberg, Vigdis; Loubere, Paul; Prins, Maarten; Dijkstra, Noortje; Gluchowska, Marta

2018-04-01

The relationships between modern Arctic benthic foraminifera and their ecological controls, along with their sensitivity to rapid environmental changes, is still poorly understood. This study examines how modern benthic foraminifera respond to annual environmental changes in the glaciated Arctic fjord Kongsfjorden, western Svalbard. Large environmental gradients due to the inflow of warm and saline Atlantic Water and the influence of tidewater glaciers characterise the fjord hydrography. A transect of six multi-corer stations, from the inner to the outer fjord, was sampled in the late summers of 2005 to 2008 to study the distribution of living (rose Bengal stained) benthic foraminifera. Physical properties of the water masses were measured concurrently. In general, nearly the entire Kongsfjorden region was dominated by ubiquitous N. labradorica foraminiferal assemblage that successfully exploited the local food resources and thrived particularly well in the presence of Atlantic-derived Transformed Atlantic Water (TAW). Further, the annual investigation revealed that Kongsfjorden underwent large interannual hydrological changes during the studied years related to variable inflow of warm and saline Atlantic Water. This led to a strong fauna variability particularly at the two marginal sites: the glacially influenced inner fjord and marine influenced shelf region. We also observed significant species shift from the 'cold' to 'warm' years and an expansion of widespread and sub-arctic to boreal species into the fjord.

Seasonality of vertical flux and sinking particle characteristics in an ice-free high arctic fjord-Different from subarctic fjords?

NASA Astrophysics Data System (ADS)

Wiedmann, Ingrid; Reigstad, Marit; Marquardt, Miriam; Vader, Anna; Gabrielsen, Tove M.

2016-02-01

The arctic Adventfjorden (78°N, 15°E, Svalbard) used to be seasonally ice-covered but has mostly been ice-free since 2007. We used this ice-free arctic fjord as a model area to investigate (1) how the vertical flux of biomass (chlorophyll a and particulate organic carbon, POC) follows the seasonality of suspended material, (2) how sinking particle characteristics change seasonally and affect the vertical flux, and (3) if the vertical flux in the ice-free arctic fjord with glacial runoff resembles the flux in subarctic ice-free fjords. During seven field investigations (December 2011-September 2012), suspended biomass was determined (5, 15, 25, and 60 m), and short-term sediment traps were deployed (20, 30, 40, and 60 m), partly modified with gel-filled jars to study the size and frequency distribution of sinking particles. During winter, resuspension from the seafloor resulted in large, detrital sinking particles. Intense sedimentation of fresh biomass occurred during the spring bloom. The highest POC flux was found during autumn (770-1530 mg POC m- 2 d- 1), associated with sediment-loaded glacial runoff and high pteropod abundances. The vertical biomass flux in the ice-free arctic Adventfjorden thus resembled that in subarctic fjords during winter and spring, but a higher POC sedimentation was observed during autumn.

Landslides Cause Tsunami Waves: Insights From Aysén Fjord, Chile

NASA Astrophysics Data System (ADS)

Lastras, Galderic; Amblas, David; Calafat, Antoni M.; Canals, Miquel; Frigola, Jaime; Hermanns, Reginald L.; Lafuerza, Sara; Longva, Oddvar; Micallef, Aaron; Sepúlveda, Sergio A.; Vargas, Gabriel; Batist, Marc De; Daele, Maarten Van; Azpiroz, María.; Bascuñán, Ignacio; Duhart, Paul; Iglesias, Olaia; Kempf, Philipp; Rayo, Xavier

2013-08-01

On 21 April 2007, an Mw 6.2 earthquake produced an unforeseen chain of events in the Aysén fjord (Chilean Patagonia, 45.5°S). The earthquake triggered hundreds of subaerial landslides along the fjord flanks. Some of the landslides eventually involved a subaqueous component that, in turn, generated a series of displacement waves—tsunami-like waves produced by the fast entry of a subaerial landmass into a water body—within the fjord [Naranjo et al., 2009; Sepúlveda and Serey, 2009; Hermanns et al., 2013]. These waves, with run-ups several meters high along the shoreline, caused 10 fatalities. In addition, they severely damaged salmon farms, which constitute the main economic activity in the region, setting free millions of cultivated salmon with still unknown ecological consequences.

A global, high-resolution data set of ice sheet topography, cavity geometry, and ocean bathymetry

NASA Astrophysics Data System (ADS)

Schaffer, Janin; Timmermann, Ralph; Arndt, Jan Erik; Savstrup Kristensen, Steen; Mayer, Christoph; Morlighem, Mathieu; Steinhage, Daniel

2016-10-01

The ocean plays an important role in modulating the mass balance of the polar ice sheets by interacting with the ice shelves in Antarctica and with the marine-terminating outlet glaciers in Greenland. Given that the flux of warm water onto the continental shelf and into the sub-ice cavities is steered by complex bathymetry, a detailed topography data set is an essential ingredient for models that address ice-ocean interaction. We followed the spirit of the global RTopo-1 data set and compiled consistent maps of global ocean bathymetry, upper and lower ice surface topographies, and global surface height on a spherical grid with now 30 arcsec grid spacing. For this new data set, called RTopo-2, we used the General Bathymetric Chart of the Oceans (GEBCO_2014) as the backbone and added the International Bathymetric Chart of the Arctic Ocean version 3 (IBCAOv3) and the International Bathymetric Chart of the Southern Ocean (IBCSO) version 1. While RTopo-1 primarily aimed at a good and consistent representation of the Antarctic ice sheet, ice shelves, and sub-ice cavities, RTopo-2 now also contains ice topographies of the Greenland ice sheet and outlet glaciers. In particular, we aimed at a good representation of the fjord and shelf bathymetry surrounding the Greenland continent. We modified data from earlier gridded products in the areas of Petermann Glacier, Hagen Bræ, and Sermilik Fjord, assuming that sub-ice and fjord bathymetries roughly follow plausible Last Glacial Maximum ice flow patterns. For the continental shelf off Northeast Greenland and the floating ice tongue of Nioghalvfjerdsfjorden Glacier at about 79° N, we incorporated a high-resolution digital bathymetry model considering original multibeam survey data for the region. Radar data for surface topographies of the floating ice tongues of Nioghalvfjerdsfjorden Glacier and Zachariæ Isstrøm have been obtained from the data centres of Technical University of Denmark (DTU), Operation Icebridge (NASA/NSF), and Alfred Wegener Institute (AWI). For the Antarctic ice sheet/ice shelves, RTopo-2 largely relies on the Bedmap-2 product but applies corrections for the geometry of Getz, Abbot, and Fimbul ice shelf cavities. The data set is available in full and in regional subsets in NetCDF format from the PANGAEA database at doi:10.1594/PANGAEA.856844.

Synoptic events force biological productivity in Patagonian fjord ecosystems

NASA Astrophysics Data System (ADS)

Daneri, Giovanni

2016-04-01

The annual cycle of primary productivity of the Patagonian fjords has, to date, been described as a two phase system consisting of a short non productive winter phase (during June and July) and a productive phase extending from late winter (August) to autumn (May). Low levels of primary production, phytoplankton biomass and high concentrations of surface nutrients have been described as characterizing winter conditions while pulsed productivity events typifies the productivity pattern during the extended productive season. Pulsed productivity events characterize coastal waters where inorganic nutrients in surface layers are replenished following periods of intensive utilization by autotrophs. Freshwater input in Patagonian fjords in southern Chile (41-55°S) results in one of the largest estuarine regions worldwide. Here strong haline water column stratification prevents nutrient mixing to the surface layers thus potentially shutting off algal production. Our working hypothesis considered that in order to reconcile the observed pulsed productivity pattern, periodic breaking (associated to surface nutrient replenishment) and re-establishment of estuarine conditions (associated to water column stratification) would be required. Up to now however our understanding of the physical processes that control water column conditions in the Patagonian fjord area has been extremely limited. Here we present evidence linking the passage of synoptic low pressure fronts to pulsed productivity events in the Patagonian fjord area. These front controls and influence local processes of interaction between the fjord and the atmosphere generating a rapid water column response. In the specific case of the Puyuhuapi fjord we have been able to show that such synoptic fronts induce surface flow reversal and water column mixing. Phytoplankton blooming occurs after the passage of the synoptic front once calmer conditions prevail and estuarine conditions are re established. The occurrence of an extremely productive bloom of the dinoflagellate Heterocapsa sp. in July 2014, after the passage of a synoptic low pressure front provided, for the first time, strong evidence that phytoplankton blooming in the Patagonian fjord ecosystems is controlled by synoptic processes and that they are not limited by light as previously reported. This research was funded by COPAS Sur-Austral (PFB-31) and FONDECYT 1131063

The northern Uummannaq Ice Stream System, West Greenland: ice dynamics and and controls upon deglaciation

NASA Astrophysics Data System (ADS)

Lane, Timothy; Roberts, David; Rea, Brice; Cofaigh, Colm Ó.; Vieli, Andreas

2013-04-01

At the Last Glacial Maximum (LGM), the Uummannaq Ice Stream System comprised a series coalescent outlet glaciers which extended along the trough to the shelf edge, draining a large proportion of the West Greenland Ice Sheet. Geomorphological mapping, terrestrial cosmogenic nuclide (TCN) exposure dating, and radiocarbon dating constrain warm-based ice stream activity in the north of the system to 1400 m a.s.l. during the LGM. Intervening plateaux areas (~ 2000 m a.s.l.) either remained ice free, or were covered by cold-based icefields, preventing diffluent or confluent flow throughout the inner to outer fjord region. Beyond the fjords, a topographic sill north of Ubekendt Ejland prevented the majority of westward ice flow, forcing it south through Igdlorssuit Sund, and into the Uummannaq Trough. Here it coalesced with ice from the south, forming the trunk zone of the UISS. Deglaciation of the UISS began at 14.9 cal. ka BP, rapidly retreating through the overdeepened Uummannaq Trough. Once beyond Ubekendt Ejland, the northern UISS retreated northwards, separating from the south. Retreat continued, and ice reached the present fjord confines in northern Uummannaq by 11.6 kyr. Both geomorphological (termino-lateral moraines) and geochronological (14C and TCN) data provide evidence for an ice marginal stabilisation at within Karrat-Rink Fjord, at Karrat Island, from 11.6-6.9 kyr. The Karrat moraines appear similar in both fjord position and form to 'Fjord Stade' moraines identified throughout West Greenland. Though chronologies constraining moraine formation are overlapping (Fjord Stade moraines - 9.3-8.2 kyr, Karrat moraines - 11.6-6.9 kyr), these moraines have not been correlated. This ice margin stabilisation was able to persist during the Holocene Thermal Maximum (~7.2 - 5 kyr). It overrode climatic and oceanic forcings, remaining on Karrat Island throughout peaks of air temperature and relative sea-level, and during the influx of the warm West Greenland Current into the Uummannaq region. Based upon analysis of fjord bathymetry and width, this ice marginal stabilisation has been shown to have been caused by increases in topographic constriction at Karrat Island. The location of the marginal stillstand is coincident with a dramatic narrowing of fjord width and bed shallowing. These increases in local lateral resistance reduces the ice flux necessary to maintain a stable grounding line, leading to ice margin stabilisation. This acted to negate the effects of the Holocene Thermal Maximum. Following this stabilisation, retreat within Rink-Karrat Fjord continued, driven by calving into the overdeepened Rink Fjord. Rink Isbræ reached its present ice margin or beyond after 5 kyr, during the Neoglacial. In contrast, the southern UISS reached its present margin at 8.7 kyr and Jakobshavn Isbræ reached its margin by 7 kyr. This work therefore provides compelling evidence for topographically forced asynchronous, non-linear ice stream retreat between outlet glaciers in West Greenland. In addition, it has major implications for our understanding and reconstruction of mid-Holocene ice sheet extent, and ice sheet dynamics during the Holocene Thermal Maximum to Neoglacial switch.

Numerical Simulation and Sensitivity Analysis of Subglacial Meltwater Plumes: Implications for Ocean-Glacier Coupling in Rink Isbrae, West Greenland

NASA Astrophysics Data System (ADS)

Carroll, D.; Sutherland, D.; Shroyer, E.; Nash, J. D.

2014-12-01

The rate of mass loss from the Greenland Ice Sheet quadrupled over the last two decades and may be due in part to changes in ocean heat transport to marine-terminating outlet glaciers. Meltwater commonly discharges at the grounding line in these outlet glacier fjords, generating a turbulent upwelling plume that separates from the glacier face when it reaches neutral density. This mechanism is the current paradigm for setting the magnitude of net heat transport in Greenland's glacial fjords. However, sufficient observations of meltwater plumes are not available to test the buoyancy-driven circulation hypothesis. Here, we use an ocean general circulation model (MITgcm) of the near-glacier field to investigate how plume water properties, terminal height, centerline velocity and volume transport depend on the initial conditions and numerical parameter choices in the model. These results are compared to a hydrodynamic mixing model (CORMIX), typically used in civil engineering applications. Experiments using stratification profiles from the continental shelf quantify the errors associated with using far-field observatons to initialize near-glacier plume models. The plume-scale model results are then integrated with a 3-D fjord-scale model of the Rink Isbrae glacier/fjord system in west Greenland. We find that variability in the near-glacier plume structure can strongly control the resulting fjord-scale circulation. The fjord model is forced with wind and tides to examine how oceanic and atmospheric forcing influence net heat transport to the glacier.

RTopo-2: A global high-resolution dataset of ice sheet topography, ice shelf cavity geometry and ocean bathymetry

NASA Astrophysics Data System (ADS)

Timmermann, Ralph; Schaffer, Janin

2016-04-01

The RTopo-1 data set of Antarctic ice sheet/shelf geometry and global ocean bathymetry has proven useful not only for modelling studies of ice-ocean interaction in the southern hemisphere. Following the spirit of this data set, we introduce a new product (RTopo-2) that contains consistent maps of global ocean bathymetry, upper and lower ice surface topographies for Greenland and Antarctica, and global surface height on a spherical grid with now 30 arc seconds resolution. We used the General Bathymetric Chart of the Oceans (GEBCO_2014) as the backbone and added the International Bathymetric Chart of the Arctic Ocean version 3 (IBCAOv3) and the International Bathymetric Chart of the Southern Ocean (IBCSO) version 1. To achieve a good representation of the fjord and shelf bathymetry around the Greenland continent, we corrected data from earlier gridded products in the areas of Petermann Glacier, Hagen Bræ and Helheim Glacier assuming that sub-ice and fjord bathymetries roughly follow plausible Last Glacial Maximum ice flow patterns. For the continental shelf off northeast Greenland and the floating ice tongue of Nioghalvfjerdsfjorden Glacier at about 79°N, we incorporated a high-resolution digital bathymetry model including all available multibeam survey data for the region. Radar data for ice surface and ice base topographies of the floating ice tongues of Nioghalvfjerdsfjorden Glacier and Zachariæ Isstrøm have been obtained from the data centers of Technical University of Denmark (DTU), Operation Icebridge (NASA/NSF) and Alfred Wegener Institute (AWI). For the Antarctic ice sheet/ice shelves, RTopo-2 largely relies on the Bedmap-2 product but applies corrections for the geometry of Getz, Abbot and Fimbul ice shelf cavities. The data set is available in full and in regional subsets in NetCDF format from the PANGAEA database.

Evidence of Anomalously Low δ13C of Marine Organic Matter in an Arctic Fjord.

PubMed

Kumar, Vikash; Tiwari, Manish; Nagoji, Siddhesh; Tripathi, Shubham

2016-11-09

Accurate estimation of relative carbon deposition (marine vs. terrestrial) is required for understanding the global carbon budget, particularly in the Arctic region, which holds disproportionate importance with respect to global carbon cycling. Although the sedimentary organic matter (SOM) concentration and its isotopic composition are important tools for such calculations, uncertainties loom over estimates provided by organic-geochemical bulk parameters. We report carbon and nitrogen concentrations and isotopes (δ 13 C and δ 15 N) of SOM at an Arctic fjord namely Kongsfjorden. We find that the bound inorganic nitrogen (ammonium attached to the clay minerals) forms a significant proportion of total nitrogen concentration (~77% in the inner fjord to ~24% in the outer part). On removing the bound nitrogen, the C/N ratio shows that the SOM in the inner fjord is made up of terrestrial carbon while the outer fjord shows mixed marine-terrestrial signal. We further show that the marine organic matter is unusually more depleted in 13 C (~-24‰) than the terrestrial organic matter (~-22.5‰). This particular finding also helps explain high δ 13 C values of SOM as noted by earlier studies in central Arctic sediments despite a high terrestrial contribution.

36 CFR 13.1302 - Subsistence.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 13.1302 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions § 13... shall not apply to, Kenai Fjords National Park. ...

Comparison of climate related changes in two Arctic fjords, Hornsund and Porsanger

NASA Astrophysics Data System (ADS)

Aniskiewicz, Paulina; Stramska, Małgorzata

2017-04-01

In the Arctic zone the climate change is amplified in comparison to globally averaged trends, and the observed trends are variable spatially. Our research is focused on two Artic fjords: Porsanger and Horsund. Porsanger fjord is located in the coastal waters of the Barents Sea. Hornsund is one of fjords located in the western part of Svalbard archipelago. In this presentation we have used data provided by the Norwegian Meteorological Institute for three meteorological stations. Two of them are located in the Porsanger fjord (Lakselv - in the inner part, Honningsvåg - in the outer zone). The third station provides data from the Hornsund fjord. Using these data we have estimated the 33-year trends (1983-2015) of air temperature and relative humidity in each station using linear regression analysis (statistically significant at 95In the inner part of the Porsanger fjord (Lakselv) the multiyear trend of increasing annual mean air temperature has been estimated at 0.006°C per year. The monthly trends were statistically significant in May, September and November. The strongest seasonal warming has been observed in spring and autumn. The trends of increasing annual mean humidity was about 0.2In Hornsund the air temperature trend (0.2°C per year) is significantly larger than in Porsanger. The trends of air temperature were statistically significant for eight months (except March, April, June and July) and three seasons (besides spring). The trends of relative humidity were not statistically significant. Thanks to this research we can discuss how atmospheric conditions and climate related trends change in time and seasons of the year in two different Arctic regions. The project has been financed from the funds of the Leading National Research Centre (KNOW) received by the Centre for Polar Studies for the period 2014-2018. This work was also funded by the Norway Grants (NCBR contract No. 201985, project NORDFLUX). Partial support comes from the Institute of Oceanology (IO PAN).

A New Ice-sheet / Ocean Interaction Model for Greenland Fjords using High-Order Discontinuous Galerkin Methods

NASA Astrophysics Data System (ADS)

Kopera, M. A.; Maslowski, W.; Giraldo, F.

2015-12-01

One of the key outstanding challenges in modeling of climate change and sea-level rise is the ice-sheet/ocean interaction in narrow, elongated and geometrically complicated fjords around Greenland. To address this challenge we propose a new approach, a separate fjord model using discontinuous Galerkin (DG) methods, or FDG. The goal of this project is to build a separate, high-resolution module for use in Earth System Models (ESMs) to realistically represent the fjord bathymetry, coastlines, exchanges with the outside ocean, circulation and fine-scale processes occurring within the fjord and interactions at the ice shelf interface. FDG is currently at the first stage of development. The DG method provides FDG with high-order accuracy as well as geometrical flexibility, including the capacity to handle non-conforming adaptive mesh refinement to resolve the processes occurring near the ice-sheet/ocean interface without introducing prohibitive computational costs. Another benefit of this method is its excellent performance on multi- and many-core architectures, which allows for utilizing modern high performance computing systems for high-resolution simulations. The non-hydrostatic model of the incompressible Navier-Stokes equation will account for the stationary ice-shelf with sub-shelf ocean interaction, basal melting and subglacial meltwater influx and with boundary conditions at the surface to account for floating sea ice. The boundary conditions will be provided to FDG via a flux coupler to emulate the integration with an ESM. Initially, FDG will be tested for the Sermilik Fjord settings, using real bathymetry, boundary and initial conditions, and evaluated against available observations and other model results for this fjord. The overarching goal of the project is to be able to resolve the ice-sheet/ocean interactions around the entire coast of Greenland and two-way coupling with regional and global climate models such as the Regional Arctic System Model (RASM), Community Earth System Model (CESM) or Advanced Climate Model for Energy (ACME).

Compared sub-bottom profile interpretation in fjords of King George Island and Danco Coast, Antarctica

NASA Astrophysics Data System (ADS)

Rodrigo, C.; Vilches, L.; Vallejos, C.; Fernandez, R.; Molares, R.

2015-12-01

The fjords of the South Shetland Islands (Antarctica) and Danco Coast (Antarctic Peninsula) represent climatic transitional areas (subpolar to polar). The analysis of the distribution of sub-bottom facies helps to understand the prevailing sedimentary and climatic processes. This work seeks to characterize and compare the fjord seismic facies, of the indicated areas, to determine the main sedimentary processes in these regions. Compressed High-Intensity Radiated Pulse (CHIRP) records from 3.5 kHz sub-bottom profiler were obtained from the cruise: NBP0703 (2007); and pinger 3.5 kHz sub-bottom profiler records from the cruises: ECA-50 INACH (2014), and First Colombian Expedition (2015). Several seismic facies were recognized in all studied areas with some variability on their thickness and extent, and indicate the occurrence of similar sedimentary processes. These are: SSD facies (strong to weak intensity, stratified, draped sheet external shape), is interpreted as sedimentary deposits originated from suspended sediments from glaciar plumes and/or ice-rafting. This facies, in general, is thicker in the fjords of King George Island than in the larger fjords of the Danco Coast; on the other hand, within the Danco Coast area, this facies is thinner and more scarce in the smaller fjords and bays. MCM facies (moderate intensity, chaotic and with mounds) is associated with moraine deposits and/or basement. This is present in all areas, being most abundant in the Danco Coast area. WIC facies (weak intensity and chaotic) is interpreted as debris flows, which are present in both regions, but is most common in small fjords or bays in the Danco Coast, perhaps due to higher slopes of the seabed. In this work we discuss the influence of local climate, sediment plumes from the glaciers and other sedimentary processes on the distribution and geometry of the identified seismic facies.

Long Wave Runup in Asymmetric Bays and in Fjords With Two Separate Heads

NASA Astrophysics Data System (ADS)

Raz, Amir; Nicolsky, Dmitry; Rybkin, Alexei; Pelinovsky, Efim

2018-03-01

Modeling of tsunamis in glacial fjords prompts us to evaluate applicability of the cross-sectionally averaged nonlinear shallow water equations to model propagation and runup of long waves in asymmetrical bays and also in fjords with two heads. We utilize the Tuck-Hwang transformation, initially introduced for the plane beaches and currently generalized for bays with arbitrary cross section, to transform the nonlinear governing equations into a linear equation. The solution of the linearized equation describing the runup at the shore line is computed by taking into account the incident wave at the toe of the last sloping segment. We verify our predictions against direct numerical simulation of the 2-D shallow water equations and show that our solution is valid both for bays with an asymmetric L-shaped cross section, and for fjords with two heads—bays with a W-shaped cross section.

Zooplankton Distribution in Four Western Norwegian Fjords

NASA Astrophysics Data System (ADS)

Gorsky, G.; Flood, P. R.; Youngbluth, M.; Picheral, M.; Grisoni, J.-M.

2000-01-01

A multi-instrumental array constructed in the Laboratoire d'Ecologie du Plancton Marin in Villefranche sur mer, France, named the Underwater Video Profiler (UVP), was used to investigate the vertical distribution of zooplankton in four western Norwegian fjords in the summer 1996. Six distinct zoological groups were monitored. The fauna included: (a) small crustaceans (mainly copepods), (b) ctenophores (mainly lobates), (c) siphonophores (mainly physonects), (d) a scyphomedusa Periphylla periphylla, (e) chaetognaths and (f) appendicularians. The use of the non-disturbing video technique demonstrated that the distribution of large zooplankton is heterogeneous vertically and geographically. Furthermore, the abundance of non-migrating filter feeders in the deep basins of the fjords indicates that there is enough food (living and non-living particulate organic matter) to support their dietary needs. This adaptation may be considered as a strategy for survival in fjords. Specifically, living in dark, deep water reduces visual predation and population loss encountered in the upper layer due to advective processes.

Scandinavia and the Baltic Region

NASA Technical Reports Server (NTRS)

2003-01-01

Data from the Multi-angle Imaging SpectroRadiometer's vertical-viewing (nadir) camera were combined to create this cloud-free natural-color mosaic of Scandinavia and the Baltic region. The image extends from 64oN, 0oE in the northwest to 56oN, 32oE in the southeast, and has been draped over a shaded relief Digital Terrain Elevation Model from the United States Geological Survey. It is displayed in an equidistant conic projection.

The image area includes southern Norway, Sweden and Finland, northern Denmark, Estonia, Latvia and part of western Russia. Norway's rugged western coastline is deeply indented by fjords. Elongated lakes, formed by glacial erosion and deposition, are characteristic of the entire region, and are particularly dense throughout Finland and Sweden. Numerous islands are present, and a virtually continuous chain of small, scattered islands occur between Sweden and Finland. The northern and eastern waters of the Baltic Sea are almost fresh, since the Baltic receives saltwater only from the narrow and shallow sounds between Denmark and Sweden that connect it to the North Sea. Most of the major cities within the image area are coastal, including St. Petersburg, Stockholm, Helsinki, Riga, and Oslo.

The Multi-angle Imaging SpectroRadiometer (MISR) observes the daylit Earth continuously from pole to pole, and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Exploring the Diversity and Antimicrobial Potential of Marine Actinobacteria from the Comau Fjord in Northern Patagonia, Chile

PubMed Central

Undabarrena, Agustina; Beltrametti, Fabrizio; Claverías, Fernanda P.; González, Myriam; Moore, Edward R. B.; Seeger, Michael; Cámara, Beatriz

2016-01-01

Bioprospecting natural products in marine bacteria from fjord environments are attractive due to their unique geographical features. Although, Actinobacteria are well known for producing a myriad of bioactive compounds, investigations regarding fjord-derived marine Actinobacteria are scarce. In this study, the diversity and biotechnological potential of Actinobacteria isolated from marine sediments within the Comau fjord, in Northern Chilean Patagonia, were assessed by culture-based approaches. The 16S rRNA gene sequences revealed that members phylogenetically related to the Micrococcaceae, Dermabacteraceae, Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, Dietziaceae, Nocardiaceae, and Streptomycetaceae families were present at the Comau fjord. A high diversity of cultivable Actinobacteria (10 genera) was retrieved by using only five different isolation media. Four isolates belonging to Arthrobacter, Brevibacterium, Corynebacterium and Kocuria genera showed 16S rRNA gene identity <98.7% suggesting that they are novel species. Physiological features such as salt tolerance, artificial sea water requirement, growth temperature, pigmentation and antimicrobial activity were evaluated. Arthrobacter, Brachybacterium, Curtobacterium, Rhodococcus, and Streptomyces isolates showed strong inhibition against both Gram-negative Pseudomonas aeruginosa, Escherichia coli and Salmonella enterica and Gram-positive Staphylococcus aureus, Listeria monocytogenes. Antimicrobial activities in Brachybacterium, Curtobacterium, and Rhodococcus have been scarcely reported, suggesting that non-mycelial strains are a suitable source of bioactive compounds. In addition, all strains bear at least one of the biosynthetic genes coding for NRPS (91%), PKS I (18%), and PKS II (73%). Our results indicate that the Comau fjord is a promising source of novel Actinobacteria with biotechnological potential for producing biologically active compounds. PMID:27486455

The Effects of Glacial and Oceanic Advection on Spatial Patterns of Freshwater Contents and Temperatures of Small Fjords and Major Basins in Prince William Sound, Alaska

NASA Astrophysics Data System (ADS)

Gay, S. M., III

2016-02-01

Using spatial principal component (PC) analysis, the variation in freshwater contents and temperatures in the upper 100m are quantified for small fjords and primary basins within Prince William Sound, Alaska. Two EOF modes explain over 90% of the variance in the freshwater content anomalies (FWCA) giving the total magnitude and vertical structure of the FWCAs respectively. Large, positive PC amplitudes (PCAs) of modes 1 and 2 indicate stratification from surface freshening, shown also by negative surface salinity anomalies, whereas positive FWCA PCAs in conjunction with negative mode 2 amplitudes infer higher subsurface freshening due to either vertical mixing or advection. In contrast, basins with negative mode 1 amplitudes are typically salty to slightly brackish, but the mode 2 PCAs determine if the FWC is concentrated near the surface or mixed deeper in the water column. The vertical structure of the temperature anomalies (TA) is more complicated, and at least three EOF modes are required to explain over 90% of the variance. The reasons for this include differences in solar heating (i.e. local climates) modulated by cold alpine runoff and advection of cold, brackish surface and subsurface glacial water. Fjords and major basins influenced by the latter exhibit large, positive mode 1 amplitudes of FWCA and negative mode 1 and 2 PCAs of TA and FWCA respectively. In certain fjords, however, advection of glacial water into the outer basins enhances the total FWC, whereas other fjords exhibit atypically low FWC due to unusual topographic features of the watersheds and inner basins. This combination of factors leads to generally poor correlations between average FWC and watershed to fjord surface area ratios or hydrology. With exception of a few sites, gradients in FWC between the small fjords and major basins are relatively weak. Thus the main driver of baroclinic flow in northern and western PWS is cold, brackish surface and subsurface water propagating from large tidewater glacial fjords. The glacial water has a marked affect on the dynamic topography, which shows southerly baroclinic-geostrophic flows within the western sound. At Montague Strait and Hinchinbrook Entrance inflows may occur from either fresh or salty conditions; low water density of the latter being shown by negative (positive) FWCA (TA) PCAs respectively.

Submarine glaciated landscapes of central and northern British Columbia, Canada

NASA Astrophysics Data System (ADS)

Shaw, John; Lintern, Gwyn

2015-04-01

Recent systematic multibeam sonar mapping and ground-truthing surveys in the fjords and coastal waters of central and northern British Columbia, Canada, provide information on glacial processes associated with the Cordilleran Ice Sheet, and also on postglacial processes that have strongly modified the glacial terrain. During the last glacial maximum, ice covered the Coast Range, except for nunataks. Convergent streamlined glacial landforms in the Strait of Georgia testify to a strong flow of ice towards the southeast, between Vancouver Island and the mainland. During ice retreat, thick deposits of acoustically stratified glaciomarine mud were deposited in glacially over deepened basins. Retreat through the Douglas Channel fjord system was punctuated by still stands, resulting in a series of submarine moraines. Postglacial processes have created a suite of landforms that mask the primary glacial terrain: 1) Fjord floors host thick deposits of acoustically transparent postglacial mud with highly variable distribution: banks up to 80-m thick are commonly adjacent to erosional zones with glaciomarine mud exposed at the seafloor; 2) In this region of high precipitation and snowpack melt, numerous cone-shaped Holocene fan deltas developed on the fjord sidewalls transport coarse sediment to the fjord floors. Larger deltas are developed at fjord heads, notably at Kitimat and Kildala; 3) Submarine slope failures in this tectonically active area have resulted in a suite of mass transport deposits on sidewalls and fjord floors. The very large submarine slope failures at Camano Sound and KitKat Inlet occurred on the steep, rear facets of large transverse moraines, and involved the failure of glaciomarine sediment that moved into deeper basins, perhaps as a retrogressive failure. The ages of these events are unknown, although the presence of postglacial mud in the slide scar at Caamano suggests that the event at that location occurred in the late glacial or early Holocene. Also, sub-bottom profiling shows that some mass transport deposits apparent on the multibeam imagery are not recent, and are blanketed by postglacial mud. Thus, submarine slope failure has been occurring throughout postglacial time; 4) Large, detached bedrock blocks on the fjord sidewall are currently being investigated with a view to understanding their rates of movement. They are provisionally interpreted as creep features, similar to terrestrial sackung.

Impact of freshwater runoff on physical oceanography and plankton distribution in a Western Norwegian fjord: an experiment with a controlled discharge from a hydroelectric power plant

NASA Astrophysics Data System (ADS)

Kaartvedt, Stein; Svendsen, Harald

1990-10-01

Investigations were carried out in a 20-km long fjord branch prior to, during, and partly after a 51-h controlled discharge from a hydroelectric power plant. The freshwater runoff (230 m 3 s -1) generated an estuarine circulation which was most prominent along the mid-axis of the fjord. High velocities were recorded both in the outgoing surface current, with a maximum of 1 m s -1 (10 km downstream of the power plant), and in a compensatory current (registration at 10-m depth) with a maximum of 0·6 m s -1 (3 km downstream). Velocities were low at 5-m depth. During discharge, salinity increased in the surface layer and decreased at a depth of several metres because of more extensive mixing. Phytoplankton was partly flushed out in the upper layers throughout the fjord branch, but abundance increased in deeper layers in an outer station, and the horizontal patchiness increased. The vertical centre of zooplankton biomass descended significantly during running of the plant. Biomass maxima in the ingoing compensation current indicate net zooplankton import during running of the power plant, but no change in total zooplankton biomass in the fjord branch was found during this experiment.

Evidence of Anomalously Low δ13C of Marine Organic Matter in an Arctic Fjord

PubMed Central

Kumar, Vikash; Tiwari, Manish; Nagoji, Siddhesh; Tripathi, Shubham

2016-01-01

Accurate estimation of relative carbon deposition (marine vs. terrestrial) is required for understanding the global carbon budget, particularly in the Arctic region, which holds disproportionate importance with respect to global carbon cycling. Although the sedimentary organic matter (SOM) concentration and its isotopic composition are important tools for such calculations, uncertainties loom over estimates provided by organic-geochemical bulk parameters. We report carbon and nitrogen concentrations and isotopes (δ13C and δ15N) of SOM at an Arctic fjord namely Kongsfjorden. We find that the bound inorganic nitrogen (ammonium attached to the clay minerals) forms a significant proportion of total nitrogen concentration (~77% in the inner fjord to ~24% in the outer part). On removing the bound nitrogen, the C/N ratio shows that the SOM in the inner fjord is made up of terrestrial carbon while the outer fjord shows mixed marine-terrestrial signal. We further show that the marine organic matter is unusually more depleted in 13C (~−24‰) than the terrestrial organic matter (~−22.5‰). This particular finding also helps explain high δ13C values of SOM as noted by earlier studies in central Arctic sediments despite a high terrestrial contribution. PMID:27827457

Relatively high antibiotic resistance among heterotrophic bacteria from arctic fjord sediments than water - Evidence towards better selection pressure in the fjord sediments

NASA Astrophysics Data System (ADS)

Hatha, A. A. Mohamed; Neethu, C. S.; Nikhil, S. M.; Rahiman, K. M. Mujeeb; Krishnan, K. P.; Saramma, A. V.

2015-12-01

The objective of this study was to determine the prevalence of antibiotic resistance among aerobic heterotrophic bacteria and coliform bacteria from water and sediment of Kongsfjord. The study was based on the assumption that arctic fjord environments are relatively pristine and offer very little selection pressure for drug resistant mutants. In order to test the hypothesis, 200 isolates belonging to aerobic heterotrophic bacteria and 114 isolates belonging to coliforms were tested against 15 antibiotics belonging to 5 different classes such as beta lactams, aminoglycosides, quinolones, sulpha drugs and tetracyclines. Resistance to beta lactam and extended spectrum beta lactam (ESBL) antibiotics was considerably high and they found to vary significantly (p < 0.05) between heterotrophic and coliform bacteria. Though the coliforms showed significantly high level of antibiotic resistance against ESBL's extent and diversity of antibiotic resistance (as revealed by multiple antibiotic resistance index and resistance patterns), was high in the aerobic heterotrophic bacteria. Most striking observation was that isolates from fjord sediments (both heterotrophic bacteria and coliforms) in general showed relatively high prevalence of antibiotic resistance against most of the antibiotics tested, indicating to better selection pressure for drug resistance mutants in the fjord sediments.

Kenai Fjords National Park Over-the-Snow Transportation Feasibility Study.

DOT National Transportation Integrated Search

2012-01-31

Kenai Fjords National Park seeks to expand winter access to the Exit Glacier Area. Year-round access would better enable the park to accomplish its mission related to visitor experience, education, and research. The road to the area is inaccessible t...

Ocean Warming of Petermann Fjord and Glacier, North Greenland

NASA Astrophysics Data System (ADS)

Muenchow, A.; Washam, P.; Padman, L.; Nicholls, K. W.

2016-02-01

Petermann Fjord connects one of the largest floating ice shelves of Greenland to Nares Strait between northern Canada and Greenland. First ocean temperatures under the ice shelf and in the fjord were recorded in 2002 and 2003, respectively. Last observations were taken in August of 2015 as part of an interdisciplinary experiment of US, Swedish, and British scientists. The new ocean data include hydrographic sections along and across the 450-m deep sill at the entrance of the fjord, sections along and across the 200-m thick terminus of the glacier, and time series from three ocean-weather stations that collect ocean temperature, salinity, and pressure data from under the ice shelf of Petermann Gletscher in near real time. Our ocean data cover the entire 2002-2015 time period when we find statistically significant changes of ocean properties in space and time. The ocean under the ice shelf connects to ambient Nares Strait and to the grounding zone of the glacier at daily to weekly time scales via temperature and salinity correlation. More specifically, we find 1. substantial and significant ocean warming of deep fjord waters at Interannual time scales, 2. intense and rapid renewal of bottom waters inside the 1000-m deep fjord, and 3. large fluctuations of temperature and salinity within about 30-m of the glacier ice-ocean interface at daily to weekly time scales. Figure: Map of the study area with 2015 locations of CTD casts (blue and green dots), ocean-weather stations (green dots), and differential GPS (red triangles). Red contours are bottom depths at 500 and 1000-m while thick black line indicates the grounding zone where the glacier connects to the bed rock below.

Jamming of granular ice mélange in tidewater glacial fjords

NASA Astrophysics Data System (ADS)

Burton, J. C.; Cassotto, R.; Amundson, J. M.; Kuo, C. C.; Dennin, M.

2016-12-01

In tidewater glacial fjords, the open water in front of the glacier terminus is often filled with a collection of calved iceberg fragments and sea ice. For glaciers with large calving rates, this "mélange" of ice can be jam-packed, so that the flow is mostly determined by granular interactions, in addition to underlying fjord currents. As the glacier pushes the ice mélange through the fjord, the mélange will become jammed and may potentially influence calving rates if the back-stress applied to the glacier terminus is large enough. However, the stress applied by a granular ice mélange will depend on its rheology, i.e. iceberg-iceberg contact forces, geometry, friction, etc. Here we report 2D, discrete particle simulations to model the granular mechanics of ice mélange. A polydisperse collection of particles is packed into a long channel and pushed downfjord at a constant speed, the latter derived from terrestrial radar interferometry (TRI). Each individual particle experiences viscoelastic contact forces and tangential frictional forces upon collision with another particle or channel walls. We find the two most important factors that govern the total force applied to the glacier are the geometry of the channel, and the shape of the particles. In addition, our simulated velocity fields reveal shearing margins near the fjord walls with more uniform flow in the middle of the mélange, consistent with TRI observations. Finally, we find that the magnitude of the back-stress applied to the glacier terminus can influence calving, however, the maximum back-stress is limited by the buckling of icebergs into the fjord waters, so that the stress in the quasi-2D mélange is partially determined by the thickness of the mélange layer.

Springtime phytoplankton dynamics in Arctic Krossfjorden and Kongsfjorden (Spitsbergen) as a function of glacier proximity

NASA Astrophysics Data System (ADS)

Piquet, A. M.-T.; van de Poll, W. H.; Visser, R. J. W.; Wiencke, C.; Bolhuis, H.; Buma, A. G. J.

2014-04-01

The hydrographic properties of the Kongsfjorden-Krossfjorden system (79° N, Spitsbergen) are affected by Atlantic water incursions as well as glacier meltwater runoff. This results in strong physical gradients (temperature, salinity and irradiance) within the fjords. Here, we tested the hypothesis that glaciers affect phytoplankton dynamics as early as the productive spring bloom period. During two campaigns in 2007 (late spring) and 2008 (early spring) we studied hydrographic characteristics and phytoplankton variability along two transects in both fjords, using high-performance liquid chromatography (HPLC)-CHEMTAX pigment fingerprinting, molecular fingerprinting (denaturing gradient gel electrophoresis, or DGGE) and sequencing of 18S rRNA genes. The sheltered inner fjord locations remained colder during spring as opposed to the outer locations. Vertical light attenuation coefficients increased from early spring onwards, at all locations, but in particular at the inner locations. In late spring meltwater input caused stratification of surface waters in both fjords. The inner fjord locations were characterized by overall lower phytoplankton biomass. Furthermore HPLC-CHEMTAX data revealed that diatoms and Phaeocystis sp. were replaced by small nano- and picophytoplankton during late spring, coinciding with low nutrient availability. The innermost stations showed higher relative abundances of nano- and picophytoplankton throughout, notably of cyanophytes and cryptophytes. Molecular fingerprinting revealed a high similarity between inner fjord samples from early spring and late spring samples from all locations, while outer samples from early spring clustered separately. We conclude that glacier influence, mediated by early meltwater input, modifies phytoplankton biomass and composition already during the spring bloom period, in favor of low biomass and small cell size communities. This may affect higher trophic levels especially when regional warming further increases the period and volume of meltwater.

Springtime phytoplankton dynamics in the Arctic Krossfjorden and Kongsfjorden (Spitsbergen) as a function of glacier proximity

NASA Astrophysics Data System (ADS)

Piquet, A. M.-T.; van de Poll, W. H.; Visser, R. J. W.; Wiencke, C.; Bolhuis, H.; Buma, A. G. J.

2013-10-01

The hydrographic properties of the Kongsfjorden - Krossfjorden system (79° N, Spitsbergen) are affected by Atlantic water incursions as well as glacier meltwater runoff. This results in strong physical gradients (temperature, salinity and irradiance) within the fjords. Here, we tested the hypothesis that glaciers affect phytoplankton dynamics as early as the productive spring bloom period. During two campaigns in 2007 (late spring) and 2008 (early spring) we studied hydrographic characteristics and phytoplankton variability along 2 transects in both fjords, using HPLC-CHEMTAX pigment fingerprinting, molecular fingerprinting (DGGE) and sequencing of 18S rRNA genes. The sheltered inner fjord locations remained colder during spring as opposed to the outer locations. Vertical light attenuation coefficients increased from early spring onwards, at all locations, but in particular at the inner locations. During the end of spring, meltwater input had stratified surface waters throughout the fjords. The inner fjord locations were characterized by overall lower phytoplankton biomass. Furthermore HPLC-CHEMTAX data revealed that diatoms and Phaeocystis sp. were replaced by small nano- and picophytoplankton during late spring, coinciding with low nutrient availability. The innermost stations showed higher relative abundances of nano- and picophytoplankton throughout, notably of cyanophytes and cryptophytes. Molecular fingerprinting revealed a high similarity between inner fjord samples from early spring and late spring samples from all locations, while outer samples from early spring clustered separately. We conclude that glacier influence, mediated by early meltwater input, modifies phytoplankton biomass and composition already during the spring bloom period, in favor of low biomass and small cell size communities. This may affect higher trophic levels especially when regional warming further increases the period and volume of meltwater.

Movement of pulsed resource subsidies from kelp forests to deep fjords.

PubMed

Filbee-Dexter, Karen; Wernberg, Thomas; Norderhaug, Kjell Magnus; Ramirez-Llodra, Eva; Pedersen, Morten Foldager

2018-05-01

Resource subsidies in the form of allochthonous primary production drive secondary production in many ecosystems, often sustaining diversity and overall productivity. Despite their importance in structuring marine communities, there is little understanding of how subsidies move through juxtaposed habitats and into recipient communities. We investigated the transport of detritus from kelp forests to a deep Arctic fjord (northern Norway). We quantified the seasonal abundance and size structure of kelp detritus in shallow subtidal (0‒12 m), deep subtidal (12‒85 m), and deep fjord (400‒450 m) habitats using a combination of camera surveys, dive observations, and detritus collections over 1 year. Detritus formed dense accumulations in habitats adjacent to kelp forests, and the timing of depositions coincided with the discrete loss of whole kelp blades during spring. We tracked these blades through the deep subtidal and into the deep fjord, and showed they act as a short-term resource pulse transported over several weeks. In deep subtidal regions, detritus consisted mostly of fragments and its depth distribution was similar across seasons (50% of total observations). Tagged pieces of detritus moved slowly out of kelp forests (displaced 4‒50 m (mean 11.8 m ± 8.5 SD) in 11‒17 days, based on minimum estimates from recovered pieces), and most (75%) variability in the rate of export was related to wave exposure and substrate. Tight resource coupling between kelp forests and deep fjords indicate that changes in kelp abundance would propagate through to deep fjord ecosystems, with likely consequences for the ecosystem functioning and services they provide.

Geomorphic and shallow-acoustic investigation of an Antarctic Peninsula fjord system using high-resolution ROV and shipboard geophysical observations: Ice dynamics and behaviour since the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

García, Marga; Dowdeswell, J. A.; Noormets, R.; Hogan, K. A.; Evans, J.; Ó Cofaigh, C.; Larter, R. D.

2016-12-01

Detailed bathymetric and sub-bottom acoustic observations in Bourgeois Fjord (Marguerite Bay, Antarctic Peninsula) provide evidence on sedimentary processes and glacier dynamics during the last glacial cycle. Submarine landforms observed in the 50 km-long fjord, from the margins of modern tidewater glaciers to the now ice-distal Marguerite Bay, are described and interpreted. The landforms are grouped into four morpho-sedimentary systems: (i) glacial advance and full-glacial; (ii) subglacial and ice-marginal meltwater; (iii) glacial retreat and neoglaciation; and (iv) Holocene mass-wasting. These morpho-sedimentary systems have been integrated with morphological studies of the Marguerite Bay continental shelf and analysed in terms of the specific sedimentary processes and/or stages of the glacial cycle. They demonstrate the action of an ice-sheet outlet glacier that produced drumlins and crag-and-tail features in the main and outer fjord. Meltwater processes eroded bedrock channels and ponds infilled by fine-grained sediments. Following the last deglaciation of the fjord at about 9000 yr BP, subsequent Holocene neoglacial activity involved minor readvances of a tidewater glacier terminus in Blind Bay. Recent stillstands and/or minor readvances are inferred from the presence of a major transverse moraine that indicates grounded ice stabilization, probably during the Little Ice Age, and a series of smaller landforms that reveal intermittent minor readvances. Mass-wasting processes also affected the walls of the fjord and produced scars and fan-shaped deposits during the Holocene. Glacier-terminus changes during the last six decades, derived from satellite images and aerial photographs, reveal variable behaviour of adjacent tidewater glaciers. The smaller glaciers show the most marked recent retreat, influenced by regional physiography and catchment-area size.

Genetic Structure in a Small Pelagic Fish Coincides with a Marine Protected Area: Seascape Genetics in Patagonian Fjords.

PubMed

Canales-Aguirre, Cristian B; Ferrada-Fuentes, Sandra; Galleguillos, Ricardo; Hernández, Cristián E

2016-01-01

Marine environmental variables can play an important role in promoting population genetic differentiation in marine organisms. Although fjord ecosystems have attracted much attention due to the great oscillation of environmental variables that produce heterogeneous habitats, species inhabiting this kind of ecosystem have received less attention. In this study, we used Sprattus fuegensis, a small pelagic species that populates the inner waters of the continental shelf, channels and fjords of Chilean Patagonia and Argentina, as a model species to test whether environmental variables of fjords relate to population genetic structure. A total of 282 individuals were analyzed from Chilean Patagonia with eight microsatellite loci. Bayesian and non-Bayesian analyses were conducted to describe the genetic variability of S. fuegensis and whether it shows spatial genetic structure. Results showed two well-differentiated genetic clusters along the Chilean Patagonia distribution (i.e. inside the embayment area called TicToc, and the rest of the fjords), but no spatial isolation by distance (IBD) pattern was found with a Mantel test analysis. Temperature and nitrate were correlated to the expected heterozygosities and explained the allelic frequency variation of data in the redundancy analyses. These results suggest that the singular genetic differences found in S. fuegensis from inside TicToc Bay (East of the Corcovado Gulf) are the result of larvae retention bya combination of oceanographic mesoscale processes (i.e. the west wind drift current reaches the continental shelf exactly in this zone), and the local geographical configuration (i.e. embayment area, islands, archipelagos). We propose that these features generated an isolated area in the Patagonian fjords that promoted genetic differentiation by drift and a singular biodiversity, adding support to the existence of the largest marine protected area (MPA) of continental Chile, which is the Tic-Toc MPA.

New imaging of submarine landslides from the 1964 earthquake near Whittier, Alaska, and a comparison to failures in other Alaskan fjords

USGS Publications Warehouse

Haeussler, Peter J.; Parsons, Thomas E.; Finlayson, David P.; Hart, Patrick J.; Chaytor, Jason D.; Ryan, Holly F; Lee, Homa J.; Labay, Keith A.; Peterson, Andrew; Liberty, Lee

2014-01-01

The 1964 Alaska M w 9.2 earthquake triggered numerous submarine slope failures in fjords of southern Alaska. These failures generated local tsunamis, such as at Whittier, where they inundated the town within 4 min of the beginning of shaking. Run-up was up to 32 m, with 13 casualties. We collected new multibeam bathymetry and high-resolution sparker seismic data in Passage Canal, and we examined bathymetry changes before and after the earthquake. The data reveal the debris flow deposit from the 1964 landslides, which covers the western 5 km of the fjord bottom. Individual blocks in the flow are up to 145-m wide and 25-m tall. Bathymetry changes show the mass transfer deposits originated from the fjord head and Whittier Creek deltas and had a volume of about 42 million m3. The 1964 deposit has an average thickness of ∼5.4 m. Beyond the debris flow, the failures likely deposited a ∼4.6-m thick megaturbidite in a distal basin. We have studied the 1964 submarine landslides in three fjords. All involved failure of the fjord-head delta. All failures eroded basin-floor sediments and incorporated them as they travelled. All the failures deposited blocks, but their size and travel distances varied greatly. We find a correlation between maximum block size and maximum tsunami run-up regardless of the volume of the slides. Lastly, the fjord’s margins were influenced by increased supply of glacial sediments during the little ice age, which along with a long interseismic interval (∼900 years) may have caused the 1964 earthquake to produce particularly numerous and large submarine landslides.

Salinity and temperature structure of a freezing Arctic fjord-monitored by white whales (Delphinapterus leucas)

NASA Astrophysics Data System (ADS)

Lydersen, Christian; Nøst, Ole Anders; Lovell, Phil; McConnell, Bernie J.; Gammelsrød, Tor; Hunter, Colin; Fedak, Michael A.; Kovacs, Kit M.

2002-12-01

In this study we report results from satellite-linked conductivity-temperature-depth (CTD) loggers that were deployed on wild, free-ranging white whales to study the oceanographic structure of an Arctic fjord, Storfjorden, Svalbard. The whales dove to the bottom of the fjord routinely during the study and occupied areas with up to 90% ice-cover, where performance of conventional ship-based CTD-casts would have been difficult. During the initial period of freezing in the fjord, over a period of approximately 2 weeks, 540 CTD profiles were successfully transmitted. The data indicate that Storfjorden has a substantial inflow of warm North Atlantic Water; this is contrary to conventional wisdom that has suggested that it contains only cold Arctic water. This study confirms that marine-mammal-based CTDs have enormous potential for cost-effective, future oceanographic studies; many different marine mammal species target oceanographic discontinuities for foraging and thus may be good `adaptive samplers' that naturally seek areas of high oceanographic interest.

Contamination of arctic Fjord sediments by Pb-Zn mining at Maarmorilik in central West Greenland.

PubMed

Perner, K; Leipe, Th; Dellwig, O; Kuijpers, A; Mikkelsen, N; Andersen, T J; Harff, J

2010-07-01

This study focuses on heavy metal contamination of arctic sediments from a small Fjord system adjacent to the Pb-Zn "Black Angel" mine (West Greenland) to investigate the temporal and spatial development of contamination and to provide baseline levels before the mines re-opening in January 2009. For this purpose we collected multi-cores along a transect from Affarlikassaa Fjord, which received high amounts of tailings from 1973 to 1990, to the mouth of Qaumarujuk Fjord. Along with radiochemical dating by (210)Pb and (137)Cs, geochemical analyses of heavy metals (e.g. As, Cd, Hg, Pb, and Zn) were carried out. Maximum contents were found at 12 cm depth in Affarlikassaa. After 17 years the mine last closed, specific local hydrographic conditions continue to disperse heavy metal enriched material derived from the Affarlikassaa into Qaumarujuk. Total Hg profiles from multi-cores along the transect clearly illustrate this transport and spatial distribution pattern of the contaminated material. Copyright 2010 Elsevier Ltd. All rights reserved.

The glacimarine sediment budget of the Nares Strait-Petermann Fjord area since the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Jakobsson, M.; Hogan, K.; Mayer, L. A.; Mix, A. C.; Nielsen, T.; Kamla, E.; Stranne, C.; Eriksson, B.; Jerram, K.

2016-12-01

During the Petermann 2015 Expedition of the Swedish icebreaker Oden more than 6500 line-km of high-resolution chirp sub-bottom profiles (2-7 kHz) were acquired in Petermann Fjord and Nares Strait in the area immediately outside of the fjord. The sub-bottom profiles reveal a highly-variable distribution of post-glacial sediment that appears to be largely controlled by the rugged relief of the underlying bedrock. Sediment thicknesses are between 0-60 m above bedrock and comprise predominantly acoustically-stratified, homogeneous to transparent acoustic facies. In Petermann Fjord itself unlithified sediment cover typically comprises two units: an underlying acoustically-transparent unit overlain by an acoustically-stratified unit. Both of these units are conformable over scoured and fairly flat bedrock terrain; small basins are present only locally. Outside of the fjord are a few local sedimentary basins containing up to 40 m of stratified basin-fill deposits, and several areas of stacked mass-flow deposits. Glacial lineations both in the fjord and Nares Strait are formed in an acoustically-homogenous unit that underlies stratified and transparent units. In addition to the sub-bottom profiles, approximately 780 line-km of 2D seismic reflection profiles were acquired using an airgun (210 cu in.) and a 300-m long streamer. These profiles have allowed us to map full unlithified sediment thicknesses down to basement in the area. Here we present the results of this mapping and we calculate the volumes of a prominent grounding-zone wedge at the mouth of Petermann Fjord, and smaller GZWs in Kennedy Channel. These features demarcate former still-stand positions of grounded ice retreating through this system, both towards the present-day grounding line of Petermann Glacier and southwards through Nares Strait. Post-glacial sediment volumes are also calculated and the sedimentary processes responsible for their distribution examined. These data, when combined with chronological information, will provide sediment fluxes through the Petermann system and help us to identify how the system has responded to a past global warming event, namely the last deglaciation. This is particularly important in light of the recent thinning and acceleration of NW Greenland's marine-terminating outlet glaciers at present.

Sensitivity of the marine-terminating margins to Holocene climate change in south and southeast Greenland

NASA Astrophysics Data System (ADS)

Levy, L.; Larsen, N. K.; Kjaer, K. H.; Bjork, A. A.; Kjeldsen, K. K.; Funder, S.; Kelly, M. A.; Howley, J. A.

2016-12-01

The marine-terminating glaciers of the Greenland Ice Sheet (GrIS) are responding rapidly to present-day climate change. More than one-third of the GrIS's discharge flows to the ocean through the marine-terminating outlet glaciers of southeastern Greenland, making it a potentially important region of the ice sheet. Documenting how these outlet glaciers have responded to longer-term past climate change (i.e. the Holocene) allows for more accurate predictions of their response to future climate changes. Here, we present 36 new 10Be ages on boulders perched on bedrock and on bedrock that record the timing of ice marginal fluctuations in several fjords in southeast and south Greenland, a region where little is known about past ice fluctuations due to its relative inaccessibility. We show that at Skjoldungen Sund (63.4N), deglaciation was rapid, beginning by 10.1 ± 0.4 ka. Deglaciation occurred concurrently at Timmiarmiut Fjord (62.7N), 100 km to the south, at 10.3 ± 0.4 ka. We suggest that this was in response to the warming ocean and air temperatures of the early Holocene. Additionally, 10Be ages on boulders perched on bedrock just distal to the historic­ moraines in Timmiarmiut Fjord date to 1.7 ± 0.1 ka, indicating the presence of a late Holocene advance prior to the Little Ice Age. In southern Greenland, deglaciation at Lindenow Fjord (60.6N), which drains the Julienhåb ice cap, occurred at 11.2 ± 0.4 ka. The ice then retreated up-fjord at a rate of 70-100 m yr-1, comparable with modern retreat rates of 30-100 m yr-1. We hypothesize that the earlier deglaciation at Lindenow Fjord by 1 ka may indicate that the Julienhåb ice cap was more sensitive to early Holocene warming than the GrIS. Additional 10Be ages from Prins Christen Fjord and near Qaqortoq are forthcoming. These new 10Be ages provide a longer-term perspective of marine-terminating outlet glacier fluctuations in Greenland and show that the ice sheet responded sensitively to Holocene climate change.

The use of XRF core scanner technique to identify anthropogenic chronological markers for dating recent sediments and for mapping and estimating the quantity of contaminated sediments in different fjord settings in western Norway

NASA Astrophysics Data System (ADS)

Haflidason, H.; Thorsen, L.; Soldal, O. L.

2016-12-01

Following the initiation of the industrial revolution in Norway at the early 1900´s many of the heavy industrial factories established at that time were located in inner fjord systems of western Norway. The advantage was an easy access to cheap electricity, but the main disadvantage has been that the pollution from this industrial activity has been transported into fjord systems where the circulation of the water masses has been fairly limited leading to a high concentration of heavy metals in the fjord basin sediments. The recently developed non-destructive X-ray Fluorescence (XRF) core scanning technique offers new possibilities to obtain near-continuous records of bulk element composition in marine records. This new analytical geochemical method can measure the bulk element content directly from the surface sediment archives within a period of seconds and with a resolution up to 200 microns. By applying this method on rapidly deposited sediments one can reconstruct a continuous record of carbonate content on a sub-decadal to annual scale. This kind of high-resolution records can also be compared directly with historical and instrumental records from the same area. This offers new possibilities to identify in an effective way the geochemical anomalies in the sediment column and estimate the variability of the industrially produced elements as e.g. Cu, Zn and Pb and their distribution and thickness/quantity in fjord basin sediments. Examples will be presented demonstrating the close linkage between the industrial production history and the entrance of these elements in the fjord sediments. Identification of these elements offers an excellent opportunity to date the recent marine sediments using these elements as an event spike and also to reconstruct the history of pollution in these fjord basin sediments. As the precision of the XRF element detection is high the time of full recovery to natural conditions of the basin sediments, after close down of these factories, can be calculated.

Spatio-temporal Variation in Glacier Ice as Habitat for Harbor Seals in an Alaskan Tidewater Glacier Fjord

NASA Astrophysics Data System (ADS)

Womble, J. N.; McNabb, R. W.; Gens, R.; Prakash, A.

2015-12-01

Some of the largest aggregations of harbor seals (Phoca vitulina richardii) in Alaska occur in tidewater glacier fjords where seals rest upon icebergs that are calved from tidewater glaciers into the marine environment. The distribution, amount, and size of floating ice in fjords are likely important factors influencing the spatial distribution and abundance of harbor seals; however, fine-scale characteristics of ice habitat that are used by seals have not been quantified using automated methods. We quantified the seasonal changes in ice habitat for harbor seals in Johns Hopkins Inlet, a tidewater glacier fjord in Glacier Bay National Park, Alaska, using aerial photography, object-based image analysis, and spatial models. Aerial photographic surveys (n = 53) were conducted of seals and ice during the whelping (June) and molting (August) seasons from 2007-2014. Surveys were flown along a grid of 12 transects and high-resolution digital photos were taken directly under the plane using a vertically aimed camera. Seal abundance and spatial distribution was consistently higher during June (range: 1,672-4,340) than August (range: 1,075-2,582) and corresponded to the spatial distribution and amount of ice. Preliminary analyses from 2007 suggest that the average percent of icebergs (ice ≥ than 1.6m2) and brash ice (ice < 1.6m2) per scene were greater in June (icebergs: 1.8% ± 1.6%; brash ice: 43.8% ± 38.9%) than August (icebergs: 0.2% ± 0.7%; brash ice; 15.8% ± 26.4%). Iceberg angularity (an index of iceberg shape) was also greater in June (1.7 ± 0.9) than August (0.9 ± 0.9). Potential factors that may influence the spatio-temporal variation in ice habitat for harbor seals in tidewater glacier fjords include frontal ablation rates of glaciers, fjord circulation, and local winds. Harbor seals exhibit high seasonal fidelity to tidewater glacier fjords, thus understanding the relationships between glacier dynamics and harbor seal distribution will be critical for understanding how future changes in tidewater glaciers may impact harbor seals.

Biogeochemistry of Framvaren, A permanently Anoxic Fjord

NASA Astrophysics Data System (ADS)

Millero, Frank J.

Recently (May 28-30, 1986), a workshop was held in Farsund, Norway, to discuss the biogeochemistry of an anoxic fjord called Framvaren. In the last 7 years a group of marine scientists from Norway, Sweden, Canada, and the United States has been studying this fjord. The workshop was held to discuss the recent findings of this international effort. A new expedition is planned in February 1987 (provided that the ice is thick enough) and in June 1988. Marine chemists, microbiologists, or geologists interested in participating in this study should contact Jens Skei (Norwegian Institute of Water Research, PB Box 333, Blindern, Oslo 3, Norway), who is coordinating the investigations.

Tall tower landscape scale N2O flux measurements in a Danish agricultural and urban, coastal area

NASA Astrophysics Data System (ADS)

Ibrom, Andreas; Lequy, Émeline; Loubet, Benjamin; Pilegaard, Kim; Ambus, Per

2015-04-01

Both technical and natural processes emit the greenhouse gas nitrous oxide (N2O) into the atmosphere. The abundant use of nitrogen (N) as fertiliser increases the concentration of reactive nitrogen (Nr) in the atmosphere, the hydrosphere and in the biosphere, i.e. in terrestrial and aquatic ecosystems. Surplus Nr is distributed across linkages to other spheres until most of it is emitted to the atmosphere as NO, N2O or N2. A complete estimate of the effects from human activities on N2O emissions must therefore include all emissions, the direct emissions and the indirect emissions that happen in interlinked spheres. For this it is necessary to assess the fluxes at least at the landscape scale. The episodic nature and the large spatial variability make it difficult to estimate the direct and indirect emissions in a landscape. Modelling requires not only to include the highly variable microbial processes in the ecosystems that produce N2O but as well the accurate simulation of lateral Nr fluxes and their effects on N2O fluxes in places remote from the primary Nr sources. In this context tall tower N2O flux measurements are particularly useful as they integrate over larger areas and can be run, continuously without disturbing the fluxes. On the other hand these measurements can be difficult to interpret due to difficulties to measure the small concentration fluctuations in the atmosphere at small flux rates and to accurately attribute the measured flux at the tower to the area that generates the flux, i.e. the source area. The Technical University of Denmark (DTU) has established eddy covariance N2O flux measurements on a 125 m tall tower at its Risø Campus as part of the EU research infrastructure project the 'Integrated non-CO2 Greenhouse gas Observing System' (InGOS). The eddy covariance system consisted of a N2O/CO quantum cascade laser, Los Gatos, Mountain View, CA, USA and a 3D sonic anemometer (USA-1), Metek, Elmshorn, Germany. The Risø peninsula lies at the eastern coastline of the Roskilde fjord on the Danish island Zealand. The tower is surrounded by the fjord, by agricultural area, forests and, in the South by the urban area of the City of Roskilde. The City of Roskilde operates a waste incinerator and a waste water treatment plant, which drains treated waste water into the fjord. The level of the measured flux values was generally relatively low. Based on the clear definition of the lag time between N2O concentrations and the vertical wind speed, fluxes were measureable over larger periods. The fluxes showed clear directional relationships indicating their large spatial and temporal variability in the landscape. Footprint calculations were performed to attribute source areas to the measured fluxes ...(Kormann and Meixner, 2001; Neftel et al., 2008). The footprint of the flux measurement included areas between 200 m and several kilometres distance from the tower. A preliminary approach was developed to generate monthly maps of N2O fluxes around the tower. Here we present the results from the first seven months of flux measurements. Based on these results we discuss the potential and the limitations of tall tower eddy covariance measurements to estimate maps of N2O fluxes and the integral value of the landscape N2O flux. Acknowledgements: This work was funded by the EU-FP7 InGOS project. We thank Ebba Dellwik (Technical University of Denmark) for providing sonic anemometer data. References: Kormann, R. and Meixner, F.X., 2001. An Analytical Footprint Model For Non-Neutral Stratification. Boundary-Layer Meteorology, 99(2): 207-224. Neftel, A., Spirig, C. and Ammann, C., 2008. Application and test of a simple tool for operational footprint evaluations. Environmental Pollution, 152(3): 644-652.

Land-ocean gradient in haline stratification and its effects on plankton dynamics and trophic carbon fluxes in Chilean Patagonian fjords (47-50°S)

NASA Astrophysics Data System (ADS)

González, H. E.; Castro, L. R.; Daneri, G.; Iriarte, J. L.; Silva, N.; Tapia, F.; Teca, E.; Vargas, C. A.

2013-12-01

Patagonian fjord systems, and in particular the fjords and channels associated with the Baker/Pascua Rivers, are currently under conspicuous natural and anthropogenic perturbations. These systems display very high variability, where limnetic and oceanic features overlap generating strong vertical and horizontal physicochemical gradients. The CIMAR 14-Fiordos cruise was conducted in the Chilean fjords located between 47° and 50°S during the spring (October-November) of 2008. The main objectives were to study vertical and horizontal gradients in physical, chemical and biological characteristics of the water column, and to assess plankton dynamics and trophic carbon fluxes in the fjords and channels of central-south Patagonia. The water column was strongly stratified, with a pycnocline at ca. 20 m depth separating a surface layer of silicic acid-rich freshwater discharged by rivers, from the underlying nitrate- and orthophosphate-rich Subantarctic waters. The outflows from the Baker and Pascua Rivers, which range annually between 500 and 1500 m3 s-1, generate the strong land-ocean gradient in salinity (1-32 psu) and inorganic nutrient concentrations (2-8 and 2-24 μM in nitrate and silicic-acid, respectively) we observed along the Baker Fjord. The POC:chl-a ratio fluctuated from 1087 near the fjord’s head to 175 at its oceanic end in the Penas Gulf. This change was mainly due to an increase in diatom dominance and a concurrent decrease in allochthonous POC towards the ocean. Depth-integrated net primary production (NPP) and bacterial secondary production (BSP) fluctuated between 49 and 1215 and 36 and 150 mg C m-2 d-1, respectively, with higher rates in oceanic waters. At a time series station located close to the Baker River mouth, the average NPP was lower (average 360 mg C m-2 d-1) than at more oceanic stations (average 1063 mg C m-2 d-1), and numerically dominated (45%) by the picoplankton (<2 μm) and nanoplankton (2-20 μm) size fractions. The high average vertical carbon flux (234 mg m-2 d-1) and high export production (65% of the NPP) support the idea that Patagonian fjords may behave as a net sink for CO2 during the productive (spring) season. Trophic fluxes near the head of the fjords, with oligotrophic low-salinity waters, were dominated by heterotrophic nanoflagellates (HNF) and small copepods (52 mg C m-2 d-1, each), suggesting that the microbial food web is the main trophic pathway in these environments.

Deep ventilation process in Patagonian fjord, Chile

NASA Astrophysics Data System (ADS)

Pérez-Santos, Iván; Silvan, Nelson; Castillo, Manuel; Mayorga, Nicolas; Schneider, Wolfgang; Montero, Paulina; Daneri, Giovanni; Valle-Levinson, Arnoldo; Pizarro, Oscar; Ramirez, Nadín; Igor, Gabriela; Navarro, Eduardo

2017-04-01

The Puyuhuapi Fjord (44.6° S) has previously been reported as one of the hypoxic fjords in Chilean Patagonia (dissolved oxygen -DO below 2 mL L-1). Hydrographic sampling between 1995-2016 confirmed hypoxia below 100 m depth, down to the bottom (250 m). A line of sensors at an oceanographic mooring in Puyuhuapi were deployed to continuously record the temporal-vertical behaviour of water column temperature and salinity from the surface down to 120 m, from February to July 2015. A multi-Parameter water quality sonde was deployed at the bottom of the line, with a DO optical sensor. From February to mid-May, hypoxia was sustained (1.4-1.6 mL L-1). However, from May until the end of June, DO values increased (2.8 mL L-1), exceeding the hypoxia threshold. This was the first event of deep ventilation reported in a Chilean Patagonian Fjord. During this time period, deep water temperatures increased by 1.3 °C, coinciding with the decreased in salinity from 33.6 to 32.8. The main cause of this event was attributed to the arrival of a new volume of mixed oceanic water into the fjord, transported by Modified Subantartic Water, with warm temperatures, lower salinities and slightly higher DO values, given its origin in the surface layer of the outer oceanic region. A new experiment was carried out during January-November, 2016 in order to corroborate the ventilation process and its connection with the adjacent ocean. Temperature, salinity and DO sensors were deployed in the outside fjords region close to the ocean (Melinka Channel) and in Puyuhuapi Fjord, to record the data at very high temporal resolution. The distance between both stations was 150 km. In the oceanic mooring the DO time series collected at 150 m depth showed hypoxia in summer related to the position of the Equatorial Sub-surface water, but from fall DO started to increase registering high values in August and September (4-5 mL/L) when the Subantartic Water arrive. The DO records in Puyuhuapi at 120 m showed a similar behaviour but with lower magnitude, confirmed the 2015 results. Winds and internal wave, registered with acoustic current profilers, contributed to this connection. The deep ventilation recorded in Patagonian Fjords would be helping to maintain their environmental health avoiding dead zones due to the increasing input of organic matter from salmon aquaculture.

Observed Hydrographic Variability Connecting the Continental Shelf to the Marine-Terminating Glaciers of Uummannaq Bay, West Greenland

NASA Astrophysics Data System (ADS)

Sutherland, D.; de Steur, L.; Nash, J. D.; Shroyer, E.; Mickett, J.

2016-02-01

Large-scale changes in ocean forcing, such as increased upper ocean heat content or variations in subpolar gyre circulation, are commonly implicated as factors causing the widespread retreat of Greenland's outlet glaciers. A recent surge in observational and modeling studies has shown how temperature increases and a changing subglacial discharge determine melt rates at glacier termini, driving a vigorous buoyancy-driven circulation. However, we still lack knowledge of what controls ambient water properties in the fjords themselves, i.e., how does the subpolar gyre communicate across the continental shelf towards the glacier termini. Here, we present a two-year mooring record of hydrographic variability in the Uummannaq Bay region of west Greenland. We focus on observations inside Rink Isbræ and Kangerlussuup Sermia fjords coupled with an outer mooring located in the submarine trough cutting across the shelf. We show how water properties vary seasonally inside the fjords and how they connect to variability in the trough. The two fjords exhibit large differences in temperature and salinity variability, which is possibly due to differences in the plume circulation driven by the glaciers themselves. We put these limited observations in temporal context by comparing them with observations from the nearby Davis Strait time array, and spatial context by comparing them with recent mooring records from Sermilik Fjord in southeast Greenland.

Sub-tidal Circulation in a deep-silled fjord: Douglas Channel, British Columbia (Canada)

NASA Astrophysics Data System (ADS)

Wan, Di; Hannah, Charles; Foreman, Mike

2016-04-01

Douglas Channel, a deep fjord on the west coast of British Columbia, Canada, is the main waterway in Kitimat fjord system that opens to Queen Charlotte Sound and Hecate Strait. The fjord is separated from the open shelf by a broad sill that is about 150 m deep, and there is another sill (200 m) that separates the fjord into an outer and an inner basin. This study examines the low-frequency (from seasonal to meteorological bands) circulation in Douglas Channel from data collected from three moorings deployed during 2013-2015, and the water property observations collected during six cruises (2014 and 2015). Estuarine flow dominates the circulation above the sill-depth. The deep flows are dominated by a yearly renewal that takes place from early June to September, and this dense water renews both basins in the form of gravity currents at 0.1 - 0.2 m/s with a thickness of 100 m. At other times of the year, the deep flow structures and water properties suggest horizontal and vertical processes and support the re-circulation idea in the inner and the outer basins. The near surface current velocity fluctuations are dominated by the along-channel wind. Overall, the circulation in the meteorological band is a mix of the estuarine flow, direct wind driven flow, and the baroclinic response to changes to the surface pressure gradient caused by the wind driven currents.

The shellfish enigma across the Mesolithic-Neolithic transition in southern Scandinavia

NASA Astrophysics Data System (ADS)

Lewis, J. P.; Ryves, D. B.; Rasmussen, P.; Olsen, J.; Knudsen, K.-L.; Andersen, S. H.; Weckström, K.; Clarke, A. L.; Andrén, E.; Juggins, S.

2016-11-01

The well-known and widespread replacement of oysters (abundant during the Mesolithic period) by cockles and mussels in many Danish Stone Age shell middens ca. 5900 cal yrs BP coincides with the transition to agriculture in southern Scandinavia. This human resource shift is commonly believed to reflect changing resource availability, driven by environmental and/or climatic change at the Mesolithic-Neolithic transition rather than cultural choice. While several hypotheses have been proposed to explain the ;Mesolithic-Neolithic oyster decline;, an explanation based on a sudden freshening of the inner Danish waters has received most attention. Here, for the first time, we test and refute this long-standing hypothesis that declining salinity explains the marked reduction in oysters identified within numerous shell middens across coastal Denmark at the Mesolithic-Neolithic transition using quantitative and qualitative salinity inference from several, independent proxies (diatoms, molluscs and foraminifera) from multiple Danish fjord sites. Alternatively, we attribute the oyster decline to other environmental causes (particularly changing sedimentation), ultimately driven by external climatic forcing. Critical application of such high-quality environmental archives can reinvigorate archaeological debates and can aid in understanding and managing environmental change in increasingly impacted coastal regions.

Greenland's 20th Century retreat illuminated - great spatial variability with strong connections to subglacial topography and fjord bathymetry

NASA Astrophysics Data System (ADS)

Bjork, A. A.; Kjeldsen, K. K.; Boeckel, M. V.; Korsgaard, N. J.; Fenty, I. G.; Khan, S. A.; Mouginot, J.; Morlighem, M.; Rignot, E. J.; Dowdeswell, J. A.; Kjaer, K. H.

2017-12-01

Mass loss acceleration from the Greenland Ice Sheet is a dominant contributor in recent global sea-level rise, and has been for several decades. While ice sheet wide mass loss has recently been documented from the end of the Little Ice Age (c. 1900 CE) to the 1980s, the detailed changes during this period remain poorly known. In this study, we map glacier margins of Greenland's 310 largest outlet glaciers in order to get the full picture of the 20th Century mass loss. We take advantage of the rich history of aerial photography over Greenland and combine photos from archives in Denmark, Norway, United Kingdom, and United States. We supplement the historical aerial photographs with declassified US spy satellite imagery and recent satellite imagery to document glacial retreat and advance on a decadal scale. With recent advances in bathymetry mapping and subglacial topography mapping, we are able to show that spatial differences in retreat throughout the last 100 years are largely controlled by the underlying topography. Our study further highlights hotspots of past rapid mass loss in Greenland, and discusses implications for periods of regional stability and advance.

Coastal Freshening Prevents Fjord Bottom Water Renewal in Northeast Greenland: A Mooring Study From 2003 to 2015

NASA Astrophysics Data System (ADS)

Boone, Wieter; Rysgaard, Søren; Carlson, Daniel F.; Meire, Lorenz; Kirillov, Sergei; Mortensen, John; Dmitrenko, Igor; Vergeynst, Leendert; Sejr, Mikael K.

2018-03-01

The freshwater content of the Arctic Ocean and its bordering seas has recently increased. Observing freshening events is an important step toward identifying the drivers and understanding the effects of freshening on ocean circulation and marine ecosystems. Here we present a 13 year (2003-2015) record of temperature and salinity in Young Sound-Tyrolerfjord (74°N) in Northeast Greenland. Our observations show that strong freshening occurred from August 2005 to August 2007 (-0.92 psu or -0.46 psu yr-1) and from August 2009 to August 2013 (-0.66 psu or -0.17 psu yr-1). Furthermore, temperature-salinity analysis from 2004 to 2014 shows that freshening of the coastal water ( range at sill depth: 33.3 psu in 2005 to 31.4 psu in 2007) prevented renewal of the fjord's bottom water. These data provide critical observations of interannual freshening rates in a remote fjord in Greenland and in the adjacent coastal waters and show that coastal freshening impacts the fjord hydrography, which may impact the ecosystem dynamics in the long term.

Chlorophyll-a thin layers in the Magellan fjord system: The role of the water column stratification

NASA Astrophysics Data System (ADS)

Ríos, Francisco; Kilian, Rolf; Mutschke, Erika

2016-08-01

Fjord systems represent hotspots of primary productivity and organic carbon burial. However, the factors which control the primary production in mid-latitude fjords are poorly understood. In this context, results from the first fine-scale measurements of bio-oceanographic features in the water column of fjords associated with the Strait of Magellan are presented. A submersible fluorescence probe (FP) was used to measure the Chlorophyll-a (Chl-a) concentration in situ, along with conductivity, temperature, hydrostatic pressure (depth) and dissolved oxygen (CTD-O2) of the water column. The Austral spring results of 14 FP-CTD-O2 profiles were used to define the vertical and horizontal patches of the fluorescent pigment distribution and their spatial relations with respect to the observed hydrographic features. Three zones with distinct water structures were defined. In all zones, the 'brown' spectral group (diatoms and dinoflagellates) predominated accounting for >80 wt% of the phytoplankton community. Thin layers with high Chl-a concentration were detected in 50% of the profiles. These layers harbored a substantial amount (30-65 wt%) of the phytoplankton biomass. Stratification was positively correlated to the occurrence of Chl-a thin layers. In stable and highly stratified water columns the integrated Chl-a concentration was higher and frequently located within thin layers whereas well mixed water columns displayed lower values and more homogeneous vertical distribution of Chl-a. These results indicate that mixing/stability processes are important factors accounting to the vertical distribution of Chl-a in Magellan fjords.

Earth Observation taken by the Expedition 20 crew

NASA Image and Video Library

2009-09-06

ISS020-E-039083 (6 Sept. 2009) --- Glacier outlet in the Southern Patagonian Ice Field of Chile is featured in this image photographed by an Expedition 20 crew member on the International Space Station. The Southern Patagonian Ice Field of Chile and Argentina hosts a spectacular array of glaciers and associated glacial features within the southern Andes Mountains. Glaciers flowing downhill on the eastern side of the mountains have outlets into several large freshwater lakes. On the western side of the mountains, glaciers release ice into the Pacific Ocean via an intricate network of fjords. Fjords are steep valleys originally cut by glaciers during periods of lower sea level that are now inundated. As glaciers flow into the fjord, ice at the front of the glacier begins to break off and form icebergs that can float out to sea ? a process known as calving. This detailed photograph shows the merged outlet of Penguin Glacier and HPS 19 into a fjord carved into the snow-covered mountains of the southern Andes. The designation HPS stands for Hielo Patagonico Sur (e.g. Southern Patagonian Ice field) and is used to identify glaciers that have no other geographic name. Ice flowing into the fjord begins to break up at center, forming numerous icebergs ? the largest visible in this image is approximately 2 kilometers in width. The large ice masses visible at center have a coarse granular appearance due to variable snow cover, and mixing and refreezing of ice fragments prior to floating free.

Glacimarine sedimentation in Petermann Fjord and Nares Strait, NW Greenland

NASA Astrophysics Data System (ADS)

Hogan, Kelly; Jakobsson, Martin; Mayer, Larry; Mix, Alan; Nielsen, Tove; Kamla, Elina; Reilly, Brendan; Heirman, Katrina An; Stranne, Christian; Mohammed, Rezwan; Eriksson, Bjorn; Jerram, Kevin

2017-04-01

Here we build on preliminary results from 6500 line-km of high-resolution chirp sub-bottom profiles (2-7 kHz) acquired in Petermann Fjord and Nares Strait during the Petermann 2015 Expedition of the Swedish icebreaker Oden. We map the unlithified sediment cover in Peterman Fjord, which consists of up to 3 conformable "drape" units and calculate volumes of this assumed "post-glacial" fill. In Nares Strait we have mapped sediment volumes in local basins just beyond the sill at the Petermann Fjord-mouth: do these sediments represent material flushed out from the grounding zone of Petermann Glacier when it was grounded at the sill? In this vein, and interestingly, some of the thickest sediments that we observe are found close to a grounding-zone wedge (GZW) in Nares Strait that represents a former grounding zone of ice retreating southwards through the strait. We also map conformable units across Nares Strait and consider the similarities between these and the sediment units in the fjord. Do the strong reflections between the units represent the same climatic, oceanographic or process-shift both inside and outside the fjord? We also aim to tie our new acoustic stratigraphy to sediment-core data (lithofacies, dates) and, therefore, to comment on the age of the mapped sediment units and present ideas on the glacimarine flux of material to the Petermann-Nares system. Primary sediment delivery to the seafloor in this environment is thought to be predominantly through sedimentation from meltwater plumes but also of iceberg-rafted debris (IRD). However, sediment redeposition by slope failures on a variety of scales also occurs and has focussed sediments into discrete basins where the seafloor is rugged. This work - which aims to relate past sediment, meltwater and iceberg fluxes to changes in climate - will help us to identify how the system has responded to a past global warming event, namely the last deglaciation. This is particularly relevant in light of the recent thinning and acceleration of NW Greenland's marine-terminating outlet glaciers.

Late Holocene glacial history of Petermann Fjord, Northwest Greenland: Non-destructive CT, XRF, and magnetic results from OD1507 sediment cores

NASA Astrophysics Data System (ADS)

Reilly, B. T.; Stoner, J. S.; Mix, A. C.; Jakobsson, M.; Jennings, A. E.; Walczak, M.; Dyke, L. M.; Cheseby, M.; Albert, S. W.; Wiest, J.

2016-12-01

An international and interdisciplinary expedition to Nares Strait and Petermann Fjord, Northwest Greenland, onboard the Swedish Icebreaker Oden July-September 2015 (OD1507) sought to understand the Holocene history of the Petermann glacial system among other research objectives. Petermann Glacier, which terminates as a floating ice-tongue in Petermann Fjord, is thought to be especially sensitive to ice-ocean interactions. While limited historical observations dating back to 1876 suggest the Petermann Ice Tongue extends about 70-90 km from the grounding-line, large calving events in 2010 and 2012 reduced the ice-tongue extent to about 45 km from the grounding-line. A suite of 14 marine sediment cores recovered a range of glacio-marine facies that form an along fjord (15-80 km from the grounding-line) and an across fjord depth (473-1041 meters water depth) transect. CT scans clearly identify four primary fjord facies, including bioturbated, IRD-rich, laminated and mud with stratified graded sand layers. The latter of these occurs near the modern grounding-line. Additionally, a new MATLAB routine is used to quantify clasts >2 mm in size from the CT scans. XRF sediment geochemical changes mirror magnetic mineral concentrations and are driven by varying contribution of Ca-rich and Ca-poor sources, which we interpret as a reflection of the mixing of the local carbonate rocks and crystalline basement excavated by the ice sheet. Initial paleomagnetic results isolate a strong and stable characteristic remanent magnetization which show remarkable similarity to paleosecular variation (PSV) recorded in nearby mid-late Holocene varved lakes on Ellesmere Island. This non-destructive dataset provides robust correlations, indicating a coherent and dynamic record of changes in the Petermann glacial system during the late Holocene, including evidence for a significant grounding-line retreat followed by the growth and relative paleo-extent of the modern Petermann Ice Tongue.

Early Diagenesis of Trace Elements in Modern Fjord Sediments of the High Arctic

NASA Astrophysics Data System (ADS)

Herbert, L.; Riedinger, N.; Aller, R. C.; Jørgensen, B. B.; Wehrmann, L.

2017-12-01

Marine sediments are critical repositories for elements that are only available at trace concentrations in seawater, such as Fe, Mn, Co, Ni, As, Mo, and U. The behavior of these trace elements in the sediment is governed by a dynamic interplay of diagenetic reactions involving organic carbon, Fe and Mn oxides, and sulfur phases. In the Arctic fjords of Svalbard, glacial meltwater delivers large amounts of reactive Fe and Mn oxides to the sediment, while organic carbon is deposited episodically and diluted by lithogenic material. These conditions result in pronounced Fe and Mn cycling, which in turn drives other diagenetic processes such as rapid sulfide oxidation. These conditions make the Svalbard fjords ideal sites for investigating trace element diagenesis because they allow resolution of the interconnections between Fe and Mn dynamics and trace element cycling. In August 2016, we collected sediment cores from three Svalbard fjords and analyzed trace elements in the pore water and solid sediment over the top meter. Initial results reveal the dynamic nature of these fjords, which are dominated by non-steady state processes and episodic events such as meltwater pulses and phytoplankton blooms. Within this system, the distribution of As appears to be strongly linked to the Fe cycle, while Co and Ni follow Mn; thus, these three elements may be released from the sediment through diffusion and bioturbation along with Fe and Mn. The pore water profiles of U and Mo indicate removal processes that are independent from Fe or Mn, and which are rather unexpected given the apparent diagenetic conditions. Our results will help elucidate the processes controlling trace element cycling in a dynamic, glacially impacted environment and will ultimately contribute to our understanding of the role of fjords in the biogeochemical cycling of trace elements in a rapidly changing Arctic Ocean.

Tidal analysis of surface currents in the Porsanger fjord in northern Norway

NASA Astrophysics Data System (ADS)

Stramska, Malgorzata; Jankowski, Andrzej; Cieszyńska, Agata

2016-04-01

In this presentation we describe surface currents in the Porsanger fjord (Porsangerfjorden) located in the European Arctic in the vicinity of the Barents Sea. Our analysis is based on data collected in the summer of 2014 using High Frequency radar system. Our interest in this fjord comes from the fact that this is a region of high climatic sensitivity. One of our long-term goals is to develop an improved understanding of the undergoing changes and interactions between this fjord and the large-scale atmospheric and oceanic conditions. In order to derive a better understanding of the ongoing changes one must first improve the knowledge about the physical processes that create the environment of the fjord. The present study is the first step in this direction. Our main objective in this presentation is to evaluate the importance of tidal forcing. Tides in the Porsanger fjord are substantial, with tidal range on the order of about 3 meters. Tidal analysis attributes to tides about 99% of variance in sea level time series recorded in Honningsvåg. The most important tidal component based on sea level data is the M2 component (amplitude of ~90 cm). The S2 and N2 components (amplitude of ~ 20 cm) also play a significant role in the semidiurnal sea level oscillations. The most important diurnal component is K1 with amplitude of about 8 cm. Tidal analysis lead us to the conclusion that the most important tidal component in observed surface currents is also the M2 component. The second most important component is the S2 component. Our results indicate that in contrast to sea level, only about 10 - 20% of variance in surface currents can be attributed to tidal currents. This means that about 80-90% of variance can be credited to wind-induced and geostrophic currents. This work was funded by the Norway Grants (NCBR contract No. 201985, project NORDFLUX). Partial support for MS comes from the Institute of Oceanology (IO PAN).

A Sensitivity Analysis of Triggers and Mechanisms of Mass Movements in Fjords

NASA Astrophysics Data System (ADS)

Overeem, I.; Lintern, G.; Hill, P.

2016-12-01

Fjords are characterized by rapid sedimentation as they typically drain glaciated river catchments with high seasonal discharges and large sediment evacuation rates. For this reason, fjords commonly experience submarine mass movements; failures of the steep delta front that trigger tsunamis, and turbidity currents or debris flows. Repeat high-resolution bathymetric surveys, and in-situ process measurements collected in fjords in British Columbia, Canada, indicate that mass movements occur many times per year in some fjords and are more rare and of larger magnitude in other fjords. We ask whether these differences can be attributed to river discharge characteristics or to grainsize characteristics of the delivered sediment. To test our ideas, we couple a climate-driven river sediment transport model, HydroTrend, and a marine sedimentation model, Sedflux2D, to explore the triggers of submarine failures and mechanisms of subsequent turbidity and debris flows. HydroTrend calculates water and suspended sediment transport on a daily basis based on catchment characteristics, glaciated area, lakes and temperature and precipitation regime. Sedflux uses the generated river time-series to simulate delta plumes, failures and mass movements with separate process models. Model uncertainty and parameter sensitivity are assessed using Dakota Tools, which allows for a systematic exploration of the effects of river basin characteristics and climate scenarios on occurrence of hyperpycnal events, delta front sedimentation rate, submarine pore pressure, failure frequency and size, and run-out distances. Preliminary simulation results point to the importance of proglacial lakes and lakes abundance in the river basin, which has profound implications for event-based sediment delivery to the delta apex. Discharge-sediment rating curves can be highly variable based on these parameters. Distinction of turbidity currents and debris flows was found to be most sensitive to both earthquake frequency and delta front grainsize. As a first step we compare these model experiments against field data from the Squamish River and Delta in Howe Sound, BC.

Genetic Structure in a Small Pelagic Fish Coincides with a Marine Protected Area: Seascape Genetics in Patagonian Fjords

PubMed Central

Ferrada-Fuentes, Sandra; Galleguillos, Ricardo; Hernández, Cristián E.

2016-01-01

Marine environmental variables can play an important role in promoting population genetic differentiation in marine organisms. Although fjord ecosystems have attracted much attention due to the great oscillation of environmental variables that produce heterogeneous habitats, species inhabiting this kind of ecosystem have received less attention. In this study, we used Sprattus fuegensis, a small pelagic species that populates the inner waters of the continental shelf, channels and fjords of Chilean Patagonia and Argentina, as a model species to test whether environmental variables of fjords relate to population genetic structure. A total of 282 individuals were analyzed from Chilean Patagonia with eight microsatellite loci. Bayesian and non-Bayesian analyses were conducted to describe the genetic variability of S. fuegensis and whether it shows spatial genetic structure. Results showed two well-differentiated genetic clusters along the Chilean Patagonia distribution (i.e. inside the embayment area called TicToc, and the rest of the fjords), but no spatial isolation by distance (IBD) pattern was found with a Mantel test analysis. Temperature and nitrate were correlated to the expected heterozygosities and explained the allelic frequency variation of data in the redundancy analyses. These results suggest that the singular genetic differences found in S. fuegensis from inside TicToc Bay (East of the Corcovado Gulf) are the result of larvae retention bya combination of oceanographic mesoscale processes (i.e. the west wind drift current reaches the continental shelf exactly in this zone), and the local geographical configuration (i.e. embayment area, islands, archipelagos). We propose that these features generated an isolated area in the Patagonian fjords that promoted genetic differentiation by drift and a singular biodiversity, adding support to the existence of the largest marine protected area (MPA) of continental Chile, which is the Tic-Toc MPA. PMID:27505009

Quantification and Analysis of Icebergs in a Tidewater Glacier Fjord Using an Object-Based Approach.

PubMed

McNabb, Robert W; Womble, Jamie N; Prakash, Anupma; Gens, Rudiger; Haselwimmer, Christian E

2016-01-01

Tidewater glaciers are glaciers that terminate in, and calve icebergs into, the ocean. In addition to the influence that tidewater glaciers have on physical and chemical oceanography, floating icebergs serve as habitat for marine animals such as harbor seals (Phoca vitulina richardii). The availability and spatial distribution of glacier ice in the fjords is likely a key environmental variable that influences the abundance and distribution of selected marine mammals; however, the amount of ice and the fine-scale characteristics of ice in fjords have not been systematically quantified. Given the predicted changes in glacier habitat, there is a need for the development of methods that could be broadly applied to quantify changes in available ice habitat in tidewater glacier fjords. We present a case study to describe a novel method that uses object-based image analysis (OBIA) to classify floating glacier ice in a tidewater glacier fjord from high-resolution aerial digital imagery. Our objectives were to (i) develop workflows and rule sets to classify high spatial resolution airborne imagery of floating glacier ice; (ii) quantify the amount and fine-scale characteristics of floating glacier ice; (iii) and develop processes for automating the object-based analysis of floating glacier ice for large number of images from a representative survey day during June 2007 in Johns Hopkins Inlet (JHI), a tidewater glacier fjord in Glacier Bay National Park, southeastern Alaska. On 18 June 2007, JHI was comprised of brash ice ([Formula: see text] = 45.2%, SD = 41.5%), water ([Formula: see text] = 52.7%, SD = 42.3%), and icebergs ([Formula: see text] = 2.1%, SD = 1.4%). Average iceberg size per scene was 5.7 m2 (SD = 2.6 m2). We estimate the total area (± uncertainty) of iceberg habitat in the fjord to be 455,400 ± 123,000 m2. The method works well for classifying icebergs across scenes (classification accuracy of 75.6%); the largest classification errors occur in areas with densely-packed ice, low contrast between neighboring ice cover, or dark or sediment-covered ice, where icebergs may be misclassified as brash ice about 20% of the time. OBIA is a powerful image classification tool, and the method we present could be adapted and applied to other ice habitats, such as sea ice, to assess changes in ice characteristics and availability.

Bathymetry of Torssukatak fjord and one century of glacier stability

NASA Astrophysics Data System (ADS)

An, L.; Rignot, E. J.; Morlighem, M.

2017-12-01

Marine-terminating glaciers dominate the evolution of the Greenland Ice Sheet(GrIS) mass balance as they control 90% of the ice discharge into the ocean. Warm air temperatures thin the glaciers from the top to unground ice fronts from the bed. Warm oceans erode the submerged grounded ice, causing the grounding line to retreat. To interpret the recent and future evolution of two outlet glaciers, Sermeq Avangnardleq (AVA) and Sermeq Kujatdleq (KUJ) in central West Greenland, flowing into the ice-choked Torssukatak fjord (TOR), we need to know their ice thickness and bed topography and the fjord bathymetry. Here, we present a novel mapping of the glacier bed topography, ice thickness and sea floor bathymetry near the grounding line using high resolution airborne gravity data from AIRGrav collected in August 2012 with a helicopter platform, at 500 m spacing grid, 50 knots ground speed, 80 m ground clearance, with submilligal accuracy, i.e. higher than NASA Operation IceBridge (OIB)'s 5.2 km resolution, 290 knots, and 450 m clearance. We also employ MultiBeam Echo Sounding data (MBES) collected in the fjord since 2009. We had to wait until the summer of 2016, during Ocean Melting Greenland (OMG), to map the fjord bathymetry near the ice fronts for the first time. We constrain the 3D inversion of the gravity data with MBES in the fjord and a reconstruction of the glacier bed topography using mass conservation (MC) on land ice. The seamless topography obtained across the grounding line reveal the presence of a 300-m sill for AVA, which explains why this glacier has been stable for a century, despite changes in surface melt and ocean-induced melt and the presence of a deep fjord (800 m) in front of the glacier. For KUJ, we also reveal the presence of a wide sill (300 m depth) near the current ice front which explains its stability and the stranding of iceberg debris in front of the glacier. The results shed new light on the evolution of these glaciers and explain their apparent stability. The data also reveal the presence of a deep bed upstream, indicating a potential for rapid retreat if ocean and surface melting are able to dislodge the glaciers from their stabilizing sills. This work was funded by NASA Cryosphere Program and from a grant by the Gordon and Betty Moore Foundation.

Quantification and Analysis of Icebergs in a Tidewater Glacier Fjord Using an Object-Based Approach

PubMed Central

McNabb, Robert W.; Womble, Jamie N.; Prakash, Anupma; Gens, Rudiger; Haselwimmer, Christian E.

2016-01-01

Tidewater glaciers are glaciers that terminate in, and calve icebergs into, the ocean. In addition to the influence that tidewater glaciers have on physical and chemical oceanography, floating icebergs serve as habitat for marine animals such as harbor seals (Phoca vitulina richardii). The availability and spatial distribution of glacier ice in the fjords is likely a key environmental variable that influences the abundance and distribution of selected marine mammals; however, the amount of ice and the fine-scale characteristics of ice in fjords have not been systematically quantified. Given the predicted changes in glacier habitat, there is a need for the development of methods that could be broadly applied to quantify changes in available ice habitat in tidewater glacier fjords. We present a case study to describe a novel method that uses object-based image analysis (OBIA) to classify floating glacier ice in a tidewater glacier fjord from high-resolution aerial digital imagery. Our objectives were to (i) develop workflows and rule sets to classify high spatial resolution airborne imagery of floating glacier ice; (ii) quantify the amount and fine-scale characteristics of floating glacier ice; (iii) and develop processes for automating the object-based analysis of floating glacier ice for large number of images from a representative survey day during June 2007 in Johns Hopkins Inlet (JHI), a tidewater glacier fjord in Glacier Bay National Park, southeastern Alaska. On 18 June 2007, JHI was comprised of brash ice (x¯ = 45.2%, SD = 41.5%), water (x¯ = 52.7%, SD = 42.3%), and icebergs (x¯ = 2.1%, SD = 1.4%). Average iceberg size per scene was 5.7 m2 (SD = 2.6 m2). We estimate the total area (± uncertainty) of iceberg habitat in the fjord to be 455,400 ± 123,000 m2. The method works well for classifying icebergs across scenes (classification accuracy of 75.6%); the largest classification errors occur in areas with densely-packed ice, low contrast between neighboring ice cover, or dark or sediment-covered ice, where icebergs may be misclassified as brash ice about 20% of the time. OBIA is a powerful image classification tool, and the method we present could be adapted and applied to other ice habitats, such as sea ice, to assess changes in ice characteristics and availability. PMID:27828967

Observations and modelling of subglacial discharge and heat transport in Godthåbsfjord (Greenland, 64 °N)

NASA Astrophysics Data System (ADS)

Bendtsen, Jørgen; Mortensen, John; Rysgaard, Søren

2017-04-01

Subglacial discharge from tidewater outlet glaciers forms convective bouyant freshwater plumes ascending close the glacier face, and entrainment of ambient bottom water increases the salinity of the water until the plume reaches its level of neutral buoyancy at sub-surface levels or reaches the surface. Relatively warm bottom water masses characterize many fjords around Greenland and therefore entrainment would also increase the temperature in the plumes and, thereby, impact the heat transport in the fjords. However, relatively few oceanographic measurements have been made in or near plumes from subglacial discharge and, therefore, the potential for subglacial discharge for increasing heat transport towards the tidewater outlet glaciers are poorly understood. We present the first direct hydrographic measurements in a plume from subglacial discharge in Godthåbsfjord (located on the western coast of Greenland) where a XCTD was launched from a helicopter directly into the plume. Measurements of the surface salinity showed that the plume only contained 7% of freshwater at the surface, implying a large entrainment with a mixing ratio of 1:13 between outflowing meltwater and saline fjord water. These observations are analyzed together with seasonal observations of ocean heat transport towards the tidewater outlet glaciers in Godthåbsfjord and we show that subglacial discharge only had modest effects on the overall heat budget in front of the glacier. These results were supported from a high-resolution three-dimensional model of Godthåbsfjord. The model explicitly considered subglacial freshwater discharge from three tidewater outlet glaciers where entrainment of bottom water was taken into account. Model results showed that subglacial discharge only affected the fjord circulation relatively close ( 10 km) to the glaciers. Thus, the main effect on heat transport was due to the freshwater discharge itself whereas the subsurface discharge and associated entrainment only had a minor dynamical effect on the fjord circulation. However, mixing of bottom water by subglacial discharge also brings large amounts of nutrients to the surface and estimates of the potential nutrient transport show that this may have a significant impact on the biological production in front of tidewater outlet glaciers. Related publications: Bendtsen, J., Mortensen, J., Lennert, K. and S. Rysgaard (2015), Heat sources for glacial ice melt in a West Greenland tidewater outlet glacier fjord: the role of subglacial freshwater discharge, Geophys. Res. Lett., 42, doi:10.1002/2015GL063846. Bendtsen, J., Mortensen, J., and Rysgaard, S. (2015), Modelling subglacial discharge and its influence on ocean heat transport in Arctic fjords, Ocean Dynamics, 65, 1535-1546, 10.1007/s10236-015-0883-1. Mortensen, J., J. Bendtsen, K. Lennert, and S. Rysgaard (2014), Seasonal variability of the circulation system in a west Greenland tidewater outlet glacier fjord, Godthåbsfjord (64°N), J. Geophys. Res. Earth Surf., 119, 2591-2603, doi:10.1002/2014JF003267. Mortensen, J., Bendtsen, J., Motyka, R. J., Lennert, K., Truffer, M., Fahnestock, M. and S. Rysgaard (2013), On the seasonal freshwater stratification in the proximity of fast-flowing tidewater outlet glaciers in a sub-Arctic sill fjord. J. Geophys. Res. 118, 1-14, doi:10.1002/jgrc.20134.

Earthshots: Satellite images of environmental change – Hubbard Glacier, Alaska, USA

USGS Publications Warehouse

Adamson, Thomas

2015-01-01

These Landsat images illustrate an unusual event that was observed twice at the terminus of Hubbard Glacier. Hubbard temporarily blocked Russell Fjord (a long, narrow inlet of the sea) from the rest of Disenchantment Bay and the Gulf of Alaska. It’s even possible that the glacier could one day permanently block the fjord.

The Petermann Glacier Experiment, NW Greenland

NASA Astrophysics Data System (ADS)

Mix, A. C.; Jakobsson, M.; Andrews, J. T.; Jennings, A. E.; Mayer, L. A.; Marcott, S. A.; Muenchow, A.; Stoner, J. S.; Andresen, C. S.; Nicholls, K. W.; Anderson, S. T.; Brook, E.; Ceperley, E. G.; Cheseby, M.; Clark, J.; Dalerum, F.; Dyke, L. M.; Einarsson, D.; Eriksson, B.; Frojd, C.; Glueder, A.; Hedman, U.; Heirman, K.; Heuzé, C.; Hogan, K.; Holden, R.; Holm, C.; Jerram, K.; Krutzfeldt, J.; Nicolas, L.; Par, L.; Lomac-MacNair, K.; Madlener, S.; McKay, J. L.; Meijer, T.; Meiton, A.; Brian, M.; Mohammed, R.; Molin, M.; Moser, C.; Normark, E.; Padman, J.; Pecnerova, P.; Reilly, B.; Reusche, M.; Ross, A.; Stranne, C.; Trinhammer, P.; Walczak, M. H.; Walczak, P.; Washam, P.; Karasti, M.; Anker, P.

2016-12-01

The Petermann Glacier Experiment is a comprehensive study on land, ocean, and ice in Northwest Greenland, staged from Swedish Icebreaker Oden in 2015 as a collaboration between the US, Sweden, UK, and Denmark. This talk introduces the strategic goals of the experiment and connects the various scientific results. Petermann Glacier drains a significant marine-based sector of the northern Greenland Ice Sheet and terminates in a floating ice tongue, one of the largest remaining systems of its kind in the northern hemisphere. Records of the modern state of Petermann Glacier and its past variations are of interest to understand the sensitivity of marine terminating outlet glaciers to change, and to constrain the rates and extent of changes that have actually occurred. With this case study we are learning the rules of large scale dynamics that cannot be understood from modern observations alone. Although past behavior is not an simple analog for the future, and no single system captures all possible behaviors, insights from these case studies can be applied through models to better project how similar systems may change in the future. The Petermann Expedition developed the first comprehensive bathymetric maps of the region, drilled through the floating ice tongue to obtain sub-shelf sediment cores near the grounding line and to monitor sub-ice conditions, recovered a broad array of sediment cores documenting changing oceanic conditions in Petermann Fjord, Hall Basin, and Nares Strait, measured watercolumn properties to trace subsurface watermasses that bring heat from the Arctic Ocean into deep Petermann Fjord to melt the base of the floating ice tongue, developed a detailed record of relative sealevel change on land to constrain past ice loads, and recovered pristine boulders for cosmogenic exposure dating of areal ice retreat on land. Together, these studies are shedding new light on the dynamics of past glaciation in Northwest Greenland, and contributing to fundamental understanding of large marine-terminating outlet glacier systems, which are threatened by global warming and poised to contribute to global sealevel rise in the future. Further information in the Petermann Glacier Experiment is available at https://petermannsglacialhistory.wordpress.com

Sediment profile imaging (SPI) and micro-electrode technologies in impact assessment studies: Example from two fjords in Southern Chile used for fish farming

NASA Astrophysics Data System (ADS)

Mulsow, S.; Krieger, Y.; Kennedy, R.

2006-10-01

Two state-of-the-art techniques were used to assess the impact of organic loading from fish farming in two fjords of Southern Chile, Pillan and Reñihue Fjords. A sediment profile imaging (SPI) camera was deployed and sediment microprofiles (oxygen, H 2S, redox and pH) were measured in undisturbed sediment cores collected using a HAPS corer. Four out of seven stations in Pillan Fjord were found to be severely disturbed: SPI images showed azoic conditions (no apparent Redox Potential Discontinuity layer, no evidence of aerobic life form, presence of an uneaten fish food layer, negative OSI scores). These findings were corroborated by very high oxygen consumption rates (700-1200 mmol m - 2 day - 1 ), H 2S concentrations increasing quickly within the sediment column and redox potential decreasing towards negative values within a few mm down core. Results for Reñihue Fjord were not so straightforward. SPI images indicated that most of the stations (R3 to R7) presented well-mixed conditions (high apparent RPD layers, presence of infauna, burrows, etc.), but oxygen profiles yielded consumption rates of 230 to 490 mmol m - 2 day - 1 and organic carbon mineralization of 2.16 to 4.53 g C m - 2 day - 1 . These latter values were close to the limit of aerobic degradation of organic matter although no visible changes were recorded within the sediment column. In view of our findings, the importance of integrating multidisciplinary methodologies in impact assessment studies was discussed.

Dynamics of dissolved organic matter in fjord ecosystems: Contributions of terrestrial dissolved organic matter in the deep layer

NASA Astrophysics Data System (ADS)

Yamashita, Youhei; McCallister, S. Leigh; Koch, Boris P.; Gonsior, Michael; Jaffé, Rudolf

2015-06-01

Annually, rivers and inland water systems deliver a significant amount of terrestrial organic matter (OM) to the adjacent coastal ocean in both particulate and dissolved forms; however, the metabolic and biogeochemical transformations of OM during its seaward transport remains one of the least understood components of the global carbon cycle. This transfer of terrestrial carbon to marine ecosystems is crucial in maintaining trophic dynamics in coastal areas and critical in global carbon cycling. Although coastal regions have been proposed as important sinks for exported terrestrial materials, most of the global carbon cycling data, have not included fjords in their budgets. Here we present distributional patterns on the quantity and quality of dissolved OM in Fiordland National Park, New Zealand. Specifically, we describe carbon dynamics under diverse environmental settings based on dissolved organic carbon (DOC) depth profiles, oxygen concentrations, optical properties (fluorescence) and stable carbon isotopes. We illustrate a distinct change in the character of DOC in deep waters compared to surface and mid-depth waters. Our results suggest that, both, microbial reworking of terrestrially derived plant detritus and subsequent desorption of DOC from its particulate counterpart (as verified in a desorption experiment) are the main sources of the humic-like enriched DOC in the deep basins of the studied fjords. While it has been suggested that short transit times and protection of OM by mineral sorption may ultimately result in significant terrestrial carbon burial and preservation in fjords, our data suggests the existence of an additional source of terrestrial OM in the form of DOC generated in deep, fjord water.

Sources and turnover of organic carbon and methane in fjord and shelf sediments off northern Norway

NASA Astrophysics Data System (ADS)

Sauer, Simone; Hong, Wei-Li; Knies, Jochen; Lepland, Aivo; Forwick, Matthias; Klug, Martin; Eichinger, Florian; Baranwal, Soma; Crémière, Antoine; Chand, Shyam; Schubert, Carsten J.

2016-10-01

To better understand the present and past carbon cycling and transformation processes in methane-influenced fjord and shelf areas of northern Norway, we compared two sediment cores from the Hola trough and from Ullsfjorden. We investigated (1) the organic matter composition and sedimentological characteristics to study the sources of organic carbon (Corg) and the factors influencing Corg burial, (2) pore water geochemistry to determine the contribution of organoclastic sulfate reduction and methanogenesis to total organic carbon turnover, and (3) the carbon isotopic signature of hydrocarbons to identify the carbon transformation processes and gas sources. High sedimentation and Corg accumulation rates in Ullsfjorden support the notion that fjords are important Corg sinks. The depth of the sulfate-methane-transition (SMT) in the fjord is controlled by the supply of predominantly marine organic matter to the sediment. Organoclastic sulfate reduction accounts for 60% of the total depth-integrated sulfate reduction in the fjord. In spite of the presence of ethane, propane, and butane, we suggest a purely microbial origin of light hydrocarbons in the sediments based on their low δ13C values. In the Hola trough, sedimentation and Corg accumulation rates changed during the deglacial-to-post-glacial transition from approximately 80 cm ka-1 to erosion at present. Thus, Corg burial in this part of the shelf is presently absent. Low organic matter content in the sediment and low rates of organoclastic sulfate reduction (only 3% of total depth-integrated sulfate reduction) entail that the shallow depth of the SMT is controlled mostly by ascending thermogenic methane from deeper sources.

Vertical and horizontal distribution of Desmophyllum dianthus in Comau Fjord, Chile: a cold-water coral thriving at low pH

PubMed Central

Richter, Claudio

2013-01-01

Cold-water corals provide an important habitat for a rich fauna along the continental margins and slopes. Although these azooxanthellate corals are considered particularly sensitive to ocean acidification, their responses to natural variations in pH and aragonite saturation are largely unknown due to the difficulty of studying their ecology in deep waters. Previous SCUBA investigations have shown an exceptionally shallow population of the cold-water coral Desmophyllum dianthus in near-surface waters of Comau Fjord, a stratified 480 m deep basin in northern Chilean Patagonia with suboxic deep waters. Here, we use a remotely operated vehicle to quantitatively investigate the distribution of D. dianthus and its physico-chemical drivers in so far uncharted naturally acidified waters. Remarkably, D. dianthus was ubiquitous throughout the fjord, but particularly abundant between 20 and 280 m depth in a pH range of 8.4 to 7.4. The persistence of individuals in aragonite-undersaturated waters suggests that present-day D. dianthus in Comau Fjord may show pre-acclimation or pre-adaptation to conditions of ocean acidification predicted to reach over 70% of the known deep-sea coral locations by the end of the century. PMID:24255810

Vertical and horizontal distribution of Desmophyllum dianthus in Comau Fjord, Chile: a cold-water coral thriving at low pH.

PubMed

Fillinger, Laura; Richter, Claudio

2013-01-01

Cold-water corals provide an important habitat for a rich fauna along the continental margins and slopes. Although these azooxanthellate corals are considered particularly sensitive to ocean acidification, their responses to natural variations in pH and aragonite saturation are largely unknown due to the difficulty of studying their ecology in deep waters. Previous SCUBA investigations have shown an exceptionally shallow population of the cold-water coral Desmophyllum dianthus in near-surface waters of Comau Fjord, a stratified 480 m deep basin in northern Chilean Patagonia with suboxic deep waters. Here, we use a remotely operated vehicle to quantitatively investigate the distribution of D. dianthus and its physico-chemical drivers in so far uncharted naturally acidified waters. Remarkably, D. dianthus was ubiquitous throughout the fjord, but particularly abundant between 20 and 280 m depth in a pH range of 8.4 to 7.4. The persistence of individuals in aragonite-undersaturated waters suggests that present-day D. dianthus in Comau Fjord may show pre-acclimation or pre-adaptation to conditions of ocean acidification predicted to reach over 70% of the known deep-sea coral locations by the end of the century.

Geographical trends of PFAS in cod livers along the Norwegian coast

PubMed Central

Valdersnes, Stig; Nilsen, Bente M.; Breivik, Joar F.; Borge, Asbjørn; Maage, Amund

2017-01-01

The level of perfluorinated alkyl substances (PFAS) was determined in North East Arctic cod (Gadus morhua) liver samples from 15 Norwegian fjords and harbors. Five harbors in the eastern part of Norway, six harbors in the western part and four harbours in the northern part. A total of 200 samples were analyzed for 16 PFAS. Determination of PFAS were carried out by LC-MS/MS following sample clean up by solid phase extraction and ultracentrifugation. The predominating PFAS was PFOS, which was found to be higher than the level of quantification (1.5 μg kg-1 wet weight) in 72% of the samples. The highest level of PFOS found was 21.8 μg kg-1 wet weight in a sample from Kragerø in the eastern part of Norway. A significantly higher level of PFOS was found in the eastern fjords and harbors compared to fjords and harbors in the western and northern part of Norway. Within the northern fjords and harbors elevated PFOS levels were found in Narvik, which may indicate a local source there. Variations in PFOS of the cod livers thus reflect differences in levels of pollution between the areas. PMID:28531177

Geographical trends of PFAS in cod livers along the Norwegian coast.

PubMed

Valdersnes, Stig; Nilsen, Bente M; Breivik, Joar F; Borge, Asbjørn; Maage, Amund

2017-01-01

The level of perfluorinated alkyl substances (PFAS) was determined in North East Arctic cod (Gadus morhua) liver samples from 15 Norwegian fjords and harbors. Five harbors in the eastern part of Norway, six harbors in the western part and four harbours in the northern part. A total of 200 samples were analyzed for 16 PFAS. Determination of PFAS were carried out by LC-MS/MS following sample clean up by solid phase extraction and ultracentrifugation. The predominating PFAS was PFOS, which was found to be higher than the level of quantification (1.5 μg kg-1 wet weight) in 72% of the samples. The highest level of PFOS found was 21.8 μg kg-1 wet weight in a sample from Kragerø in the eastern part of Norway. A significantly higher level of PFOS was found in the eastern fjords and harbors compared to fjords and harbors in the western and northern part of Norway. Within the northern fjords and harbors elevated PFOS levels were found in Narvik, which may indicate a local source there. Variations in PFOS of the cod livers thus reflect differences in levels of pollution between the areas.

Marine benthic habitat mapping of the West Arm, Glacier Bay National Park and Preserve, Alaska

USGS Publications Warehouse

Hodson, Timothy O.; Cochrane, Guy R.; Powell, Ross D.

2013-01-01

Seafloor geology and potential benthic habitats were mapped in West Arm, Glacier Bay National Park and Preserve, Alaska, using multibeam sonar, groundtruthed observations, and geological interpretations. The West Arm of Glacier Bay is a recently deglaciated fjord system under the influence of glacial and paraglacial marine processes. High glacially derived sediment and meltwater fluxes, slope instabilities, and variable bathymetry result in a highly dynamic estuarine environment and benthic ecosystem. We characterize the fjord seafloor and potential benthic habitats using the recently developed Coastal and Marine Ecological Classification Standard (CMECS) by the National Oceanic and Atmospheric Administration (NOAA) and NatureServe. Due to the high flux of glacially sourced fines, mud is the dominant substrate within the West Arm. Water-column characteristics are addressed using a combination of CTD and circulation model results. We also present sediment accumulation data derived from differential bathymetry. These data show the West Arm is divided into two contrasting environments: a dynamic upper fjord and a relatively static lower fjord. The results of these analyses serve as a test of the CMECS classification scheme and as a baseline for ongoing and future mapping efforts and correlations between seafloor substrate, benthic habitats, and glacimarine processes.

Super-long bridges with floating towers: the role of multi-box decks and Hardware-In-the-Loop technology for wind tunnel tests

NASA Astrophysics Data System (ADS)

Zasso, A.; Argentini, T.; Bayati, I.; Belloli, M.; Rocchi, D.

2017-12-01

The super long fjord crossings in E39 Norwegian project pose new challenges to long span bridge design and construction technology. Proposed solutions should consider the adoption of bridge deck with super long spans or floating solutions for at least one of the towers, due to the relevant fjord depth. At the same time, the exposed fjord environment, possibly facing the open ocean, calls for higher aerodynamic stability performances. In relation to this scenario, the present paper addresses two topics: 1) the aerodynamic advantages of multi-box deck sections in terms of aeroelastic stability, and 2) an experimental setup in a wind tunnel able to simulate the aeroelastic bridge response including the wave forcing on the floating.

Benthic Foraminiferal Stable Isotope and Dinocyst Assemblages in Sediments of the Trondheimfjord Area (Mid-Norway): Proxies for Regional Oceanographic and Climate Changes?

NASA Astrophysics Data System (ADS)

Milzer, G.; Giraudeau, J.; Faust, J.; Knies, J.; Schmidt, S.; Rühlemann, C.

2012-04-01

The Trondheimfjord is located at the west coast of Mid-Norway and is characterized by local environmental and hydrological changes that are linked to regional oceanographic and atmospheric processes in the Norwegian Sea. The North Atlantic Current (NAC) and the Norwegian Coastal Current (NCC), two major northward flowing sea surface/intermediate currents, strongly contribute to the oceanography of the Norwegian Sea and thus, to the hydrological settings of the fjord. Instrumental records indicate that the renewal of the fjord water by Atlantic-derived water masses occurs twice a year and that bottom water temperature and salinity changes reflect NAC variability. Sedimentation rates in the fjord basin exceed several mm/yr. Hence, the Trondheimfjord is an ideal location for high resolution studies of important climate-sensitive parameters such as characteristics of Atlantic-derived waters, freshwater discharge and sedimentary patterns. We measured stable isotope ratios in tests of the benthic foraminifera Melonis barleanus from surface sediments of the Trondheimfjord; δ18O ratios vary according to circulation and stratification patterns in the fjord which are linked to the topography. Based on these surface sediment measurements, as well as previous sediment core studies (Milzer et al, unpublished), we assume that benthic δ18O ratios in sedimentary archives from the Trondheimfjord reflect ocean circulation changes in the Norwegian Sea. In order to examine to which extent physico-chemical characteristics of the prevailing water masses are affecting the benthic signal in the Trondheimfjord, and how these findings can be related to oceanographic changes in the Norwegian Sea, we analyze benthic δ18O ratios from three multi-cores distributed along the fjord axis. According to 210Pb and 137Cs chronology these multi-cores contain undisturbed sedimentary records for the last 10 to 50 years, with sedimentation rates ranging from 2.5 to 7 mm/yr. We perform this analysis by comparing our stable isotope data with instrumental time-series from hydrological stations in the fjord area and over the Norwegian margin. On a decadal scale the variability of the benthic δ18O signal concurs with the temperature and salinity variability of the bottom water of the Trondheimfjord measured at different stations along the fjord axis. On a multidecadal scale, benthic δ18O variability and the instrumental datasets show different patterns, and point out the peculiarity of each core location in terms of topographic and hydrological settings. In addition, we present dinocyst census counts on the same sedimentary archives as tracers of changes in water mass characteristics induced both by NAC ventilation of the Trondheimfjord and regional climate patterns. The results show characteristic dinocyst assemblages for estuaries including seasonal hydrological variations in the Trondheimfjord which result in changes of food availability as well as mixing of water masses in the fjord.

Bathymetry and retreat of Southeast Greenland glaciers from Operation IceBridge and Ocean Melting Greenland data

NASA Astrophysics Data System (ADS)

Millan, R.; Rignot, E. J.; Morlighem, M.; Bjork, A. A.; Mouginot, J.; Wood, M.

2017-12-01

Southeast Greenland has been one of the largest contributors to ice mass loss in Greenland in part because of significant changes in glacier dynamics. The leading hypothesis for the changes in glacier dynamics is that enhanced thermal forcing from the ocean has dislodged a number of glaciers from their anchoring positions and some of them retreated rapidly along a reverse bed. The glaciers response has been observed to vary significantly from one fjord to the next, but until now there was not enough data to understand or interpret these changes. In particular, there was no data on glacier bed topography and seafloor bathymetry in the fjords. Here we present the results of new fjord mapping by the NASA Ocean Melting Greenland mission combined with a recent high-resolution airborne gravity survey by NASA Operation IceBridge. We combine these data with a reconstruction of the bed using a mass conservation approach upstream extending into the glacial fjords for the first time. In the fjord and along the ice-ocean transition, we employ a 3D inversion of gravity data to infer the bed elevation along a set of 9 survey boxes spanning south of Helheim Glacier to the southern tip of Southeast Greenland. We combine the results with an analysis of the glacier front history since the 1930's and Conductivity Temperature Depth data obtained in the fjord by OMG in 2016. The data reveals bed elevations several 100-m deeper than previously thought, for almost all the glaciers, up to 500 m for some of them. For many glaciers, the bed profiles help to completely understand the history of retreat of the glaciers. For instance, glaciers stranded on sills have been stable; glaciers on a reverse slope have retreated rapidly; and glaciers with a normal slope have retreated slowly. The mapping also helps document the extent of the marine portion of the glacier basins. In many of the fjords, we document the presence of warm, salty Atlantic Water which fuels large melt rates. We employ simulations from the MITgcm model to estimate the melt rates and further interpret the glacier retreat pattern. In addition, we estimate that more than half of the glaciers surveyed in most detail is very likely to retreat rapidly in the near future because they stand neat retrograde slope. These glaciers will contribute further to the mass loss from this part of Greenland into the ocean.

Sedimentary organic matter sources, benthic consumption and burial in west Spitsbergen fjords - Signs of maturing of Arctic fjordic systems?

NASA Astrophysics Data System (ADS)

Zaborska, Agata; Włodarska-Kowalczuk, Maria; Legeżyńska, Joanna; Jankowska, Emilia; Winogradow, Aleksandra; Deja, Kajetan

2018-04-01

Mature ecosystems sequester little organic carbon (Corg) in sediments, as the complex and effective food webs consume most available organic matter within the water column and sediment, in contrast to young systems, where a large proportion of Corg is buried in deeper sediment layers. In this paper we hypothesize that "warmer" Atlantic water influenced fjord exhibits the 'mature' system features as compared to "cooler" Arctic water influenced fjord. Corg concentrations, sources and burial rates, as well as macrobenthic community standing stocks, taxonomic and functional composition and carbon demand, were compared in two west Spitsbergen fjords that are to different extents influenced by Atlantic water and can be treated as representing a cold one (Hornsund) and a warm one (Kongsfjorden). Water, sediments and macrofauna were collected at three stations in the central basin of each fjord. Corg, Ntot, δ13Corg and δ15N were measured in suspended matter, sediment cores and possible organic matter sources. The composition of sources of sedimentary organic matter was modeled by Mix-SIAR Bayesian stable isotope mixing models. The 210Pb method was used to calculate sediment accumulation rates, Corg accumulation and burial rates. The sedimentary Corg concentration and accumulation rate were larger in Hornsund than in Kongsfjorden. The contributions of pelagic sources to the Corg in sediments were similar in both fjords, macroalgal detritus had a higher importance in Kongsfjorden, while terrestrial sources were more important in Hornsund. Similar density and species richness were noted in both fjords, but higher biomass, individual biomass, production and carbon demand of benthic communities were noted in Kongsfjorden despite the lower amounts of Corg in sediments, indicating that macrobenthos responds to quality rather than quantity of available food. Subsurface tube-building conveyer belt detritus feeders (maldanids and oweniids) were responsible for higher standing stocks and carbon consumption in Kongsfjorden. As a result of the lower Corg pool and higher benthic mineralization, the burial rates in Kongsfjorden were much lower (15 g of Corg m- 2 yr- 1) than in Hornsund (38 g of Corg m- 2 yr- 1). Our study indicates that warming of the high latitude fjordic environments may reshape the relative proportions of organic carbon sources and induce maturing of the sea bottom systems, in terms of development of stable, biologically accommodated benthic communities which more efficiently mineralize organic matter and consequently lower sequestration of organic matter in deeper sediments.

Dynamics of a vertical turbulent plume in a stratification typical of Greenland fjords: an idealized model of subglacial discharge

NASA Astrophysics Data System (ADS)

Stenberg, Erik; Ezhova, Ekaterina; Cenedese, Claudia; Brandt, Luca

2017-04-01

We the report results of large eddy simulations of a turbulent buoyant plume in a configuration providing an idealized model of subglacial discharge from a submarine glacier in stratifications typical of Greenland Fjords. We neglect a horizontal momentum of the plume and assume that its influence on the plume dynamics is small and important only close to the source. Moreover, idealized models have considered the plume adjacent to the glacier as a half-conical plume (e.g., [1]). Thus, to compare the results for such plume with the classical plume theory, developed for free plumes entraining ambient fluid from all directions, it is convenient to add the second half-conical part and consider a free plume with double the total discharge as a model. Given the estimate of the total subglacial discharge for Helheim Glacier in Sermilik Fjord [2], we perform simulations with double the total discharge in order to investigate the dynamics of the flow in typical winter and summer stratifications in Greenland fjords [3]. The plume is discharged from a round source of various diameters. In winter, when the stratification is similar to an idealised two-layers case, turbulent entrainment and generation of internal waves by the plume top are in agreement with the theoretical and numerical results obtained for turbulent jets in a two-layer stratification. In summer, instead, the stratification is more complex and turbulent entrainment is significantly reduced. The subsurface layer in summer is characterized by a strong density gradient and the oscillating plume generates non-linear internal waves which are able to mix this layer even if the plume does not penetrate to the surface. The classical theory for the integral parameters of a turbulent plume in a homogeneous fluid gives accurate predictions of the plume parameters in the weakly stratified lower layer up to the pycnocline. [1] Mankoff, K. D., F. Straneo, C. Cenedese, S. B. Das, C. D. Richards, and H. Singh, 2016: Structure and dynamics of a subglacial discharge plume in a Greenland Fjord. J. Geophys. Res., 121, doi:10.1002/2016JC011764. [2] Sciascia, R., F. Straneo, C. Cenedese, and P. Heimbach, 2013: Seasonal variability of submarine melt rate and circulation in an East Greenland fjord. J. Geophys. Res., 118, 2492-2506. [3] Straneo, F., R. Curry, D. Sutherland, G. Hamilton, C. Cenedese, K. Vage, and L. Stearns, 2011: Impact of fjord dynamics and glacial runoff on the circulation near Helheim Glacier. Nature Geosci., 4, 322-327.

Sedimentary Carbon Stocks: A National Assessment of Scotland's Fjords.

NASA Astrophysics Data System (ADS)

Smeaton, Craig; Austin, William; Davies, Althea; Howe, John

2017-04-01

Coastal sediments have been shown to be globally significant repositories for carbon (C) with an estimated 126.2 Tg of C being buried annually (Duarte et al. 2005). Though it is clear these areas are important for the long-term storage of C the actual quantity of C held within coastal sediment remains largely unaccounted for. The first step to understanding the role the coastal ocean plays in the global C cycle is to quantify the C held within these coastal sediments. Of the different coastal environment fjords have been shown to be hotspots for C burial with approximately 11 % of the annual global marine carbon sequestration occurring within fjordic environments (Smith et al. 2015). Through the development of a joint geophysical and geochemical methodology we estimated that the sediment in a mid-latitude fjord holds 26.9 ± 0.5 Mt of C (Smeaton et al., 2016), with these results suggesting that Scottish mid-latitude fjords could be a significant unaccounted store of C equivalent to their terrestrial counterparts (i.e. peatlands). Through the application of the joint geophysical and geochemical methodology developed by Smeaton et al (2016) to a number of other mid-latitude fjords, we will create detailed estimations of the sedimentary C stored at these individual sites. Using these detailed C stock estimations in conjunction with upscaling techniques we will establish the first national estimation of fjordic sedimentary C stocks. The data produced will allow for the sedimentary C stocks to be compared to other national C stocks, such as the Scottish peatlands (Chapman et al. 2009) and forestry (Forestry Commission, 2016). Alongside quantifying this large unaccounted for store of C in the coastal ocean this work also lays foundations for future work to understand the role of the coastal ocean in the global C cycle. Duarte, C. M., Middelburg, J. J., and Caraco, N.: Major role of marine vegetation on the oceanic carbon cycle, Biogeosciences, 2, 1-8, doi:10.5194/bg-2-1-2005, 2005. Smeaton, C., Austin, W. E. N., Davies, A. L., Baltzer, A., Abell, R. E., and Howe, J. A.: Substantial stores of sedimentary carbon held in mid-latitude fjords, Biogeosciences, 13, 5771-5787, doi:10.5194/bg-13-5771-2016, 2016. Smith, R. W., Bianchi, T. S., Allison, M., Savage, C., and Galy, V.: High rates of organic carbon burial in fjord sediments globally, Nat. Geosci., 8, 450-453, doi:10.1038/NGEO2421, 2015.

Insights into ice-ocean interactions and fjord circulation from fjord sea surface temperatures at the Petermann Glacier, Greenland

NASA Astrophysics Data System (ADS)

Snow, T.; Shepherd, B.; Abdalati, W.; Scambos, T. A.

2016-12-01

Dynamic processes at marine-terminating outlet glaciers are responsible for over one-third of Greenland Ice Sheet (GIS) mass loss. Enhanced intrusion of warm ocean waters at the termini of these glaciers has contributed to elevated rates of ice thinning and terminus retreat over the last two decades. In situ oceanographic measurements and modeling studies show that basal melting of glaciers and subglacial discharge can cause buoyant plumes of water to rise to the fjord surface and influence fjord circulation characteristics. The temperature of these surface waters holds clues about ice-ocean interactions and small-scale circulation features along the glacier terminus that could contribute to outlet glacier mass loss, but the magnitude and duration of temperature variability remains uncertain. Satellite remote sensing has proven very effectiver for acquiring sea surface temperatuer (SST) data from these remote regions on a long-term, consistent basis and shows promise for identifying temperature anomalies at the ice front. However, these data sets have not been widely utilized to date. Here, we use satellite-derived sea surface temperatures to identify fjord surface outflow characteristics from 2000 to present at the Petermann Glacier, which drains 4% of the GIS and is experiencing 80% of its mass loss from basal melt. We find a general SST warming trend that coincides with early sea ice breakup and precedes two major calving events and ice speedup that began in 2010. Persistent SST anomalies along the terminus provide evidence of warm outflow that is consistent with buoyant plume model predictions. However, the anomalies are not evident early in the time series, suggesting that ocean inflow and ice-ocean interactions have experienced a regime shift since 2000. Our results provide valuable insight into fjord circulation patterns and the forcing mechanisms that contribute to terminus retreat. Comparing our results to ongoing modeling experiments, time series from other outlet glaciers, and coincident in situ measurements, will help to further explain the physical processes occurring at the ice-ocean boundary and provide useful insights into the changes taking place at other GIS marine-terminating outlet glaciers.

The Influence of Subglacial Hydrology on Arctic Tidewater Glaciers and Fjords

NASA Astrophysics Data System (ADS)

Schild, Kristin M.

Mass loss from the Greenland Ice Sheet has accelerated throughout the last decade, predominantly due to a quadrupling of ice discharge by iceberg calving, submarine melting, and meltwater runoff at marine-terminating outlet glaciers. The recent acceleration has been linked to the transport of increasing amounts of meltwater, fuelled by warming temperatures. These processes include enhanced basal sliding, inefficient subglacial drainage networks, and a warming of ocean waters in contact with the glacier terminus. Understanding the impact of meltwater on tidewater glacier dynamics, both subglacially and proglacially, is a key component in predicting glacier health and future sea level rise. However, the spatial and temporal magnitude of this meltwater impact is poorly understood. The goals of this dissertation are to identify how meltwater travels subglacially through a tidewater glacier system, establish a method to monitor tidewater glacier discharge remotely, and calculate the impact of subglacial discharge on terminus stability.. The inaccessibility of subglacial and terminus environments prohibits direct hydrological observations. We use combinations of remote sensing, reanalysis models, and in situ fjord data to accomplish these research goals by measuring indicators of subglacial meltwater discharge and fjord circulation (sediment plumes exiting the terminus and the movement of small icebergs in the fjord). By monitoring the timing and duration of plumes exiting a fast-flowing Greenland tidewater glacier, we found short-term variability in meltwater discharge, persistent subglacial pathways, and evidence of over-winter subglacial storage. Using glaciers in Svalbard, we established a new method to determine sediment concentration from Landsat-8 spectral reflectance, and used this sediment concentration to quantify relative seasonal meltwater discharge at tidewater glaciers. Finally, we used the movement of icebergs and ocean temperatures to establish a terminus submarine melt rate for along-terminus fjord circulation, and use this to isolate calving due solely to subglacial meltwater discharge. The results of this dissertation help answer larger questions concerning the controls of water flow under a glacier and how that flow, and fjord circulation, influence glacier stability. Ultimately these results will inform coupled ice-ocean-climate models to predict glacier melt and sea level rise.

Bathymetry in Petermann fjord from Operation IceBridge aerogravity

NASA Astrophysics Data System (ADS)

Tinto, Kirsty J.; Bell, Robin E.; Cochran, James R.; Münchow, Andreas

2015-07-01

Petermann Glacier is a major glacier in northern Greenland, maintaining one of the few remaining floating ice tongues in Greenland. Monitoring programs, such as NASA's Operation IceBridge have surveyed Petermann Glacier over several decades and have found it to be stable in terms of mass balance, velocity and grounding-line position. The future vulnerability of this large glacier to changing ocean temperatures and climate depends on the ocean-ice interactions beneath its floating tongue. These cannot currently be predicted due to a lack of knowledge of the bathymetry underneath the ice tongue. Here we use aerogravity data from Operation IceBridge, together with airborne radar and laser data and shipborne bathymetry-soundings to model the bathymetry beneath the Petermann ice tongue. We find a basement-cored inner sill at 540-610 m depth that results in a water cavity with minimum thickness of 400 m about 25 km from the grounding line. The sill is coincident with the location of the melt rate minimum. Seaward of the sill the fjord is strongly asymmetric. The deepest point occurs on the eastern side of the fjord at 1150 m, 600 m deeper than on the western side. This asymmetry is due to a sedimentary deposit on the western side of the fjord. A 350-410 m-deep outer sill, also mapped by marine surveys, marks the seaward end of the fjord. This outer sill is aligned with the proposed Last Glacial Maximum (LGM) grounding-line position for Petermann Glacier. The inner sill likely provided a stable pinning point for the grounding line in the past, punctuating the retreat of Petermann Glacier since the LGM.

Glacimarine Sedimentary Processes and Deposits at Fjord-Terminating Tidewater Glacier Margins

NASA Astrophysics Data System (ADS)

Streuff, K.; O'Cofaigh, C.; Lloyd, J. M.; Noormets, R.; Nielsen, T.; Kuijpers, A.

2016-12-01

Many fjords along Arctic coasts are influenced by tidewater glaciers, some of them fast-flowing ice sheet outlets. Such glaciers provide important links between terrestrial and marine environments, and, due to their susceptibility to climatic and oceanographic changes, have undergone a complex history of advance and retreat since the last glacial maximum (LGM). Although a growing body of evidence has led to a better understanding of the deglacial dynamics of individual glaciers since the LGM, their overall Holocene glacimarine processes and associated sedimentary and geomorphological products often remain poorly understood. This study addresses this through a detailed analysis of sediment cores, swath bathymetric and sub-bottom profiler data collected from seven fjords in Spitsbergen and west Greenland. The sediment cores preserve a complex set of lithofacies, which include laminated and massive muds in ice-proximal, and bioturbated mud in more ice-distal settings, diamicton in iceberg-dominated areas and massive sand occurring as lenses, laminae and thick beds. These facies record the interplay of three main glacimarine processes, suspension settling, iceberg rafting and sediment gravity flows, and collectively emphasise the dominance of glacial meltwater delivery to sedimentation in high Arctic fjords. The seafloor geomorphology in the fjords shows a range of landforms that include glacial lineations associated with fast ice-flow, terminal moraines and debris lobes marking former maximum glacier extents, and small transverse moraines formed during deglaciation by glaciotectonic deformation at the grounding line and crevasse-squeezing. Additional landforms such as iceberg ploughmarks, submarine channels, pockmarks, and debris lobes formed during or after deglaciation by iceberg calving, erosion by meltwater, and sediment reworking. We present here a new model for sedimentary and geomorphological processes in front of contemporary tidewater glaciers, which integrates our findings with those from Alaska, Canada, and east Greenland.

Radioactive contamination from dumped nuclear waste in the Kara Sea--results from the joint Russian-Norwegian expeditions in 1992-1994.

PubMed

Salbu, B; Nikitin, A I; Strand, P; Christensen, G C; Chumichev, V B; Lind, B; Fjelldal, H; Bergan, T D; Rudjord, A L; Sickel, M; Valetova, N K; Føyn, L

1997-08-25

Russian-Norwegian expeditions to the Kara Sea and to dumping sites in the fjords of Novaya Zemlya have taken place annually since 1992. In the fjords, dumped objects were localised with sonar and ROV equipped with underwater camera. Enhanced levels of 137Cs, 60Co, 90Sr and 239,240Pu in sediments close to dumped containers in the Abrosimov and Stepovogo fjords demonstrated that leaching from dumped material has taken place. The contamination was inhomogeneously distributed and radioactive particles were identified in the upper 10 cm of the sediments. 137Cs was strongly associated with sediments, while 90Sr was more mobile. The contamination was less pronounced in the areas where objects presumed to be reactor compartments were located. The enhanced level of radionuclides observed in sediments close to the submarine in Stepovogo fjord in 1993 could, however, not be confirmed in 1994. Otherwise, traces of 60Co in sediments were observed in the close vicinity of all localised objects. Thus, the general level of radionuclides in waters, sediments and biota in the fjords is, somewhat higher or similar to that of the open Kara Sea, i.e. significantly lower than in other adjacent marine systems (e.g. Irish Sea, Baltic Sea, North Sea). The main sources contributing to radioactive contamination were global fallout from atmospheric nuclear weapon tests, river transport from Ob and Yenisey, marine transport of discharges from Sellafield, UK and fallout from Chernobyl. Thus, the radiological impact to man and the arctic environment of the observed leakages from dumped radioactive waste today, is considered to be low. Assuming all radionuclides are released from the waste, preliminary assessments indicate a collective dose to the world population of less than 50 man Sv.

Diet of Norwegian coastal cod (Gadus morhua) studied by using citizen science

NASA Astrophysics Data System (ADS)

Enoksen, Siri Elise; Reiss, Henning

2018-04-01

The Norwegian coastal cod (Gadus morhua) is a keystone species in the food web of northern Norwegian fjords. Their relatively stationary populations might specifically depend on local food resources, but the diet of cod has rarely been studied in fjord systems. Using a citizen science approach, where recreational anglers and tourists participated in the sampling, we studied small-scale differences in the diet composition of cod in a fjord system in northern Norway. We compared the cod diet from the MPA Saltstraumen, characterised by strong tidal currents and a highly diverse and abundant fauna, with the inner fjord area of Skjerstadfjord. The diet composition of cod significantly differed between both areas within the fjord. Although fish was the dominant prey in both areas, cod consumed > 40% invertebrates in terms of weight, even in the cod size class of 70-99 cm. The invertebrate prey also caused the observed spatial differences. In Saltstraumen, brittle stars (Ophiuroidea), crabs (Brachyura) and sea cucumbers (Holothuroidea) were important food sources for cod, while sea urchins (Echinoidea), clams (Bivalvia), shrimps (Caridea) and krill (Euphausiacea) dominated the diet in the inner Skjerstadfjord. The high densities of sessile fauna in the dynamic environment of Saltstraumen, was only partly reflected in the diet of cod, with only Holothuroidea found in 17% of the stomachs. High rates of empty stomachs (24%), cannibalism as well as a higher proportion of low-energy prey in the diet of large cod, may indicate a shortage of high quality food in Skjerstadfjord. The samples for this study were collected through a citizen science campaign. This approach might provide opportunities to be used for coastal ecological monitoring with potential applications in local ecosystem management strategies through public involvement.

The Saguenay Fjord, Quebec, Canada: Integrating marine geotechnical and geophysical data for spatial seismic slope stability and hazard assessment

USGS Publications Warehouse

Urgeles, R.; Locat, J.; Lee, H.J.; Martin, F.

2002-01-01

In 1996 a major flood occurred in the Saguenay region, Quebec, Canada, delivering several km3 of sediment to the Saguenay Fjord. Such sediments covered large areas of the, until then, largely contaminated fjord bottom, thus providing a natural capping layer. Recent swath bathymetry data have also shown that sediment landslides are widely present in the upper section of the Saguenay Fjord, and therefore, should a new event occur, it would probably expose the old contaminated sediments. Landslides in the Upper Saguenay Fjord are most probably due to earthquakes given its proximity to the Charlevoix seismic region and to that of the 1988 Saguenay earthquake. In consequence, this study tries to characterize the permanent ground deformations induced by different earthquake scenarios from which shallow sediment landslides could be triggered. The study follows a Newmark analysis in which, firstly, the seismic slope performance is assessed, secondly, the seismic hazard analyzed, and finally an evaluation of the seismic landslide hazard is made. The study is based on slope gradients obtained from EM1000 multibeam bathymetry data as well as water content and undrained shear strength measurements made in box and gravity cores. Ground motions integrating local site conditions were simulated using synthetic time histories. The study assumes the region of the 1988 Saguenay earthquake as the most likely source area for earthquakes capable of inducing large ground motions in the Upper Saguenay region. Accordingly, we have analyzed several shaking intensities to deduce that generalized sediment displacements will begin to occur when moment magnitudes exceed 6. Major displacements, failure, and subsequent landslides could occur only from earthquake moment magnitudes exceeding 6.75. ?? 2002 Elsevier Science B.V. All rights reserved.

Potential alteration of fjordal circulation due to a large floating structure—Numerical investigation with application to Hood Canal basin in Puget Sound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khangaonkar, Tarang; Wang, Taiping

Circulation in typical fjords is characterized by a shallow brackish layer at the surface over a deep long and narrow saltwater column. This surface layer is responsible for the outflow of water from the fjord, is easily disrupted by external forces, such as wind, and is influenced by freshwater inflow. In this paper, we postulate that the stability of fjordal circulation may also be vulnerable to impacts from anthropogenic alterations, such as floating structures, that could constrict the mixing and transport in the upper layers of the water column. The potential for alteration of circulation in Hood Canal, a silled-fjordmore » located inside Puget Sound, Washington, has been examined. Using classical analytical treatments along the lines formulated by Hansen and Rattray [1965], Rattray [1967], Dyer [1973] and more recently, MacCready [2004], we develop a solution applicable to a range of estuary classifications varying from a partially mixed estuary regime to classical fjord conditions. Both estuary types exist in the Puget Sound system, and we compare our analytical solution with observed data. The analysis is based on an exponential variation of eddy viscosity with depth, and it has been extended further with modifications of the free surface boundary conditions to develop a solution representing the presence of a floating bridge at the estuary/fjord entrance. The model results show that tidally averaged mean circulation under the influence of such a constraint could reduce by as much as 30 to 50 percent. The overall water quality of fjords and narrow estuaries is dependent on net circulation and flushing. A potential decrease in residual flow or a corresponding increase in residence time of this magnitude merits further study.« less

Geochemical evidence of past earthquakes in sediments of the Reloncaví fjord (Chilean Patagonia) during the last ˜ 1000 years

NASA Astrophysics Data System (ADS)

Rebolledo, Lorena; Lange, Carina; Muñoz, Práxedes; Salamanca, Marco

2014-05-01

The Chilean fjords are excellent archives of paleoearthquakes, tsunamis and landslides (St-Onge et al., 2012 in Sedimentary Geology 243-244: 89-107). Here we report on new sedimentological and geochemical evidence of past earthquakes in sediments of the Reloncavi fjord, Northern Patagonia (41° S, 72° W), during the last ~1000 years. We recovered four sediment cores from the Reloncaví fjord (RH-5B, RH-5C, RH-6B, RH7B, water depth range = 90-260 m; core length range = 45-75 cm). Age models were based on 210Pb, AMS-14C and the first appearance of the diatom Rhizosolenia setigera cf. pungens in the fossil record as statigraphic marker. The cores span the last ~122 to 800 years of sedimentation with sedimentation rates ranging between 0.1 and 0.24 cm yr-1. The cores revealed evidence of turbidites associated with the historical earthquakes of 1960, 1837, 1737 and 1575 AD, and an earlier period for which there is no historical information, 1200-1400 AD. The turbidites exhibit a grading-up pattern with sand layers, and are characterized by a decrease in organic carbon and biogenic opal, an increase in the C/N molar ratio, negative values of δ13Corg(average -27),and an increase in the relative abundance of Paralia sulcata, a diatom associated with sandy environments, being the turbite layers mainly freshwater in origen. We suggest that these turbidite layers were triggered by past earthquakes that produced movement of land from the cliff areas that surround the Reloncaví fjord. Funding: Project FONDECYT # 11110103 and COPAS Sur-Austral project PFB-31.

Oceanographic gradients and seabird prey community dynamics in glacial fjords

USGS Publications Warehouse

Arimitsu, Mayumi L.; Piatt, John F.; Madison, Erica N.; Conaway, Jeffrey S.; Hillgruber, N.

2012-01-01

Glacial fjord habitats are undergoing rapid change as a result of contemporary global warming, yet little is known about how glaciers influence marine ecosystems. These ecosystems provide important feeding, breeding and rearing grounds for a wide variety of marine organisms, including seabirds of management concern. To characterize ocean conditions and marine food webs near tidewater glaciers, we conducted monthly surveys of oceanographic variables, plankton, fish and seabirds in Kenai Fjords, Alaska, from June to August of 2007 and 2008. We also measured tidal current velocities near glacial features. We found high sediment load from glacial river runoff played a major role in structuring the fjord marine ecosystem. Submerged moraines (sills) isolated cool, fresh, stratified and silt-laden inner fjord habitats from oceanic influence. Near tidewater glaciers, surface layers of turbid glacial runoff limited availability of light to phytoplankton, but macrozooplankton were abundant in surface waters, perhaps due to the absence of a photic cue for diel migration. Fish and zooplankton community structure varied along an increasing temperature gradient throughout the summer. Acoustic measurements indicated that low density patches of fish and zooplankton were available in the surface waters near glacial river outflows. This is the foraging habitat occupied most by Kittlitz's murrelet (Brachyramphus brevirostris), a rare seabird that appears to be specialized for life in glacially influenced environments. Kittlitz's murrelets were associated with floating glacial ice, and they were more likely to occur near glaciers, in deeper water, and in areas with high acoustic backscatter. Kittlitz's murrelet at-sea distribution was limited to areas influenced by turbid glacial outflows, and where prey was concentrated near the surface in waters with low light penetration. Tidewater glaciers impart unique hydrographic characteristics that influence marine plankton and fish communities, and this has cascading effects on marine food webs in these ecosystems.

Bio-invasive ascidians in Ireland: A threat for the shellfish industry but also a source of high added value products.

PubMed

Palanisamy, Satheesh Kumar; Thomas, Olivier P; P McCormack, Grace

2018-01-01

In October 2016, a rapid assessment survey of ascidian species was conducted in shellfish farms at Killary Fjord, in the west of Ireland. Two non-indigenous solitary ascidians Ascidiella aspersa and Corella eumoyta were recorded for the first time in shellfish farms at this location. Both invasive ascidians have the potential to greatly reduce mussel production in Killary Fjord by competing with shellfish for food and habitat. Their high abundance also causes an increase in maintenance costs leading to economic losses for aquaculture farmers. Prompted by our finding of two invasive ascidians in Killary Fjord, we provide a brief review of the ecological role of ascidians and the potential of harnessing biomass from such invasive species for the production of high added value marine natural products.

Columbia Bay, Alaska: an 'upside down' estuary

USGS Publications Warehouse

Walters, R.A.; Josberger, E.G.; Driedger, C.L.

1988-01-01

Circulation and water properties within Columbia Bay, Alaska, are dominated by the effects of Columbia Glacier at the head of the Bay. The basin between the glacier terminus and the terminal moraine (sill depth of about 22 m) responds as an 'upside down' estuary with the subglacial discharge of freshwater entering at the bottom of the basin. The intense vertical mixing caused by the bouyant plume of freshwater creates a homogeneous water mass that exchanges with the far-field water through either a two- or a three-layer flow. In general, the glacier acts as a large heat sink and creates a water mass which is cooler than that in fjords without tidewater glaciers. The predicted retreat of Columbia Glacier would create a 40 km long fjord that has characteristics in common with other fjords in Prince William Sound. ?? 1988.

An earthquake in Japan caused large waves in Norwegian fjords

NASA Astrophysics Data System (ADS)

Schult, Colin

2013-08-01

Early on a winter morning a few years ago, many residents of western Norway who lived or worked along the shores of the nation's fjords were startled to see the calm morning waters suddenly begin to rise and fall. Starting at around 7:15 A.M. local time and continuing for nearly 3 hours, waves up to 1.5 meters high coursed through the previously still fjord waters. The scene was captured by security cameras and by people with cell phones, reported to local media, and investigated by a local newspaper. Drawing on this footage, and using a computational model and observations from a nearby seismic station, Bondevik et al. identified the cause of the waves—the powerful magnitude 9.0 Tohoku earthquake that hit off the coast of Japan half an hour earlier.

Pathways of Petermann Glacier's Meltwaters, Greenland

NASA Astrophysics Data System (ADS)

Heuzé, C.; Wahlin, A.; Johnson, H. L.; Muenchow, A.

2016-02-01

Radar and satellite observations suggest that the floating ice shelf of Petermann glacier, north Greenland, loses up to 80% of its mass through basal melting, caused by the intrusion of warm Atlantic water into the fjord and under the ice shelf. Although Greenland meltwaters are key to sea level rise projections and can potentially disrupt the whole ocean circulation, the fate of Petermann's glacial meltwater is still largely unknown. It is investigated here, using hydrographic observations collected during a research cruise onboard I/B Oden in August 2015. Two layers are found: one at 200 m (i.e. terminus depth) mostly on the eastern side of the fjord where a calving event occurred this summer, and one around 500 m depth (i.e. the grounding line) on the western side. At the sill, approximately 3 mSv of freshwater leave the fjord around 150 m on the eastern side. On the western side, a more complex circulation occurs as waters intrude in. Outside of the fjord in Hall Basin, only one layer is found, around 300 m, but its oxygen content and T-S properties suggests it is a mixture between Petermann's meltwater, meltwater from the neighbouring glaciers, surface run-off and sea ice. As Atlantic water warms up, it is key to monitor Greenland melting glaciers to properly assess sea level rise.

Observations and modeling of fjord sedimentation during the 30 year retreat of Columbia Glacier, AK

USGS Publications Warehouse

Love, Katherine B; Hallet, Bernard; Pratt, Thomas L.; O'Neel, Shad

2016-01-01

To explore links between glacier dynamics, sediment yields and the accumulation of glacial sediments in a temperate setting, we use extensive glaciological observations for Columbia Glacier, Alaska, and new oceanographic data from the fjord exposed during its retreat. High-resolution seismic data indicate that 3.2 × 108 m3 of sediment has accumulated in Columbia Fjord over the past three decades, which corresponds to ~5 mm a−1 of erosion averaged over the glaciated area. We develop a general model to infer the sediment-flux history from the glacier that is compatible with the observed retreat history, and the thickness and architecture of the fjord sediment deposits. Results reveal a fivefold increase in sediment flux from 1997 to 2000, which is not correlated with concurrent changes in ice flux or retreat rate. We suggest the flux increase resulted from an increase in the sediment transport capacity of the subglacial hydraulic system due to the retreat-related steepening of the glacier surface over a known subglacial deep basin. Because variations in subglacial sediment storage can impact glacial sediment flux, in addition to changes in climate, erosion rate and glacier dynamics, the interpretation of climatic changes based on the sediment record is more complex than generally assumed.

Effect of fjord geometry on tidewater glacier stability

NASA Astrophysics Data System (ADS)

Åkesson, Henning; Nisancioglu, Kerim H.; Nick, Faezeh M.

2016-04-01

Many marine-terminating glaciers have thinned, accelerated and retreated during the last two decades, broadly consistent with warmer atmospheric and oceanic conditions. However, these patterns involve considerable spatial and temporal variability, with diverse glacier behavior within the same regions. Similarly, reconstructions of marine-terminating glaciers indicate highly asynchronous retreat histories. While it is well known that retrograde slopes can cause marine ice sheet instabilities, the effect of lateral drag and fjord width has received less attention. Here, we test the hypothesis that marine outlet glacier stability is largely controlled by fjord width, and to a less extent by regional climate forcing. We employ a dynamic flowline model on idealized glacier geometries (representative of different outlet glaciers) to investigate geometric controls on decadal and longer times scales. The model accounts for driving and resistive stresses of glacier flow as well as along-flow stress transfer. It has a physical treatment of iceberg calving and a time-adaptive grid allowing for continuous tracking of grounding-line migration. We apply changes in atmospheric and oceanic forcing and show how wide and narrow fjord sections foster glacier (in)stabilities. We also evaluate the effect of including a surface mass balance - elevation feedback in such a setting. Finally, the relevance of these results to past and future marine-terminating glacier stability is discussed.

Export of Strongly Diluted Greenland Meltwater From a Major Glacial Fjord

NASA Astrophysics Data System (ADS)

Beaird, Nicholas L.; Straneo, Fiammetta; Jenkins, William

2018-05-01

The Greenland Ice Sheet has been, and will continue, losing mass at an accelerating rate. The influence of this anomalous meltwater discharge on the regional and large-scale ocean could be considerable but remains poorly understood. This uncertainty is in part a consequence of challenges in observing water mass transformation and meltwater spreading in coastal Greenland. Here we use tracer observations that enable unprecedented quantification of the export, mixing, and vertical distribution of meltwaters leaving one of Greenland's major glacial fjords. We find that the primarily subsurface meltwater input results in the upwelling of the deep fjord waters and an export of a meltwater/deepwater mixture that is 30 times larger than the initial meltwater release. Using these tracer data, the vertical structure of Greenland's summer meltwater export is defined for the first time showing that half the meltwater export occurs below 65 m.

Importance of mixotrophic nanoplankton in Aysén Fjord (Southern Chile) during austral winter

NASA Astrophysics Data System (ADS)

Czypionka, Till; Vargas, Cristian A.; Silva, Nelson; Daneri, Giovanni; González, Humberto E.; Iriarte, José Luis

2011-03-01

Mixotrophy, the combination of autotrophic and heterotrophic nutrition in the same organism, is widespread in planktonic algae. Several reports from temperate and high-latitude fjords in Scandinavia suggest the occurrence of a niche in late summer and autumn during post-bloom conditions in which mixotrophic algae can become important grazers in pelagic ecosystems, accessing the nutrients bound in their prey to overcome nutrient limitation. Here, we experimentally determined the trophic modes and bacterivory rates for the nanoplankton community (2-20 μm) in Aysén Fjord located in the Chilean Northern Patagonia during two contrasting seasons: winter and spring. While mixotrophic nanoplankton was virtually absent from the system in spring, in winter at occasions it even constituted the dominant trophic group of the nanoplankton with abundances of >900 cells mL -1. This indicates a second niche for mixotrophs in winter, when mixotrophy allows overcoming light limitation.

Observed Characteristics and Origins of Meltwaters Exported from Jakobshavn and Ilulissat Icefjord, Greenland

NASA Astrophysics Data System (ADS)

Beaird, N.; Straneo, F.; Jenkins, W. J.

2017-12-01

Jakobshavn Isbrae has undergone rapid retreat in recent decades and is now among the largest sources of anomalous ice discharge from Greenland's shrinking ice sheet. The characteristics, distribution, and pathways of meltwater sourced from Jakobshavn can have important impacts on ecosystems and regional, perhaps global, ocean circulation. Here we report on novel geochemical (noble gas) observations that enable a quantitative description of the meltwaters exiting Ilulissat Icefjord into Disko Bay, including the partition into Submarine Meltwater sources and Subglacial Discharge sources. We identify a coastally-trapped plume outside of the fjord mouth consistent with a coastal current flowing north. The plume extends to 100 m depth, and 10 km offshore. Temperature and salinity profiles inside the fjord suggest a deep-reaching buoyancy-forced overturning feeding this outflow. Relatively high Submarine Meltwater concentration (2.5%) imply a substantial contribution of iceberg meltwater to the fjord. Subglacial Discharge concentrations in the plume reach 6%.

Seasonal plankton variability in Chilean Patagonia fjords: Carbon flow through the pelagic food web of Aysen Fjord and plankton dynamics in the Moraleda Channel basin

NASA Astrophysics Data System (ADS)

González, H. E.; Castro, L.; Daneri, G.; Iriarte, J. L.; Silva, N.; Vargas, C. A.; Giesecke, R.; Sánchez, N.

2011-03-01

Two research cruises ( CIMAR 13 Fiordos) were conducted in the N-S oriented macrobasin of the Moraleda Channel (42-47°S), which includes the E-W oriented Puyuhuapi Channel and Aysen Fjord, during two contrasting productive seasons: austral winter (27 July-7 August 2007) and spring (2-12 November 2007). These campaigns set out to assess the spatio-temporal variability, defined by the local topography along Moraleda Channel, in the biological, physical, and chemical oceanographic characteristics of different microbasins and to quantify the carbon budget of the pelagic trophic webs of Aysen Fjord. Seasonal carbon fluxes and fjord-system functioning vary widely in our study area. In terms of spatial topography, two constriction sills (Meninea and Elefantes) define three microbasins along Moraleda Channel, herein the (1) north (Guafo-Meninea), (2) central (Meninea-Elefantes), and (3) south (Elefantes-San Rafael Lagoon) microbasins. In winter, nutrient concentrations were high (i.e. nitrate range: 21-14 μM) and primary production was low (153-310 mgC m -2 d -1), suggesting that reduced light radiation depressed the plankton dynamics throughout Moraleda Channel. In spring, primary production followed a conspicuous N-S gradient, which was the highest (5167 mgC m -2 d -1) in the north microbasin and the lowest (742 mgC m -2 d -1) in the south microbasin. The seasonal pattern of the semi-enclosed Puyuhuapi Channel and Aysen Fjord, however, revealed no significant differences in primary production (˜800 mgC m -2 d -1), and vertical fluxes of particulate organic carbon were nearly twice as high in spring as in winter (266 vs. 168 mgC m -2 d -1). At the time-series station (St. 79), the lithogenic fraction dominated the total sedimented matter (seston). The role of euphausiids in the biological carbon pump of the Patagonian fjords was evident, given the predominance of zooplankton fecal material, mostly euphausiid fecal strings (46% of all fecal material), among the recognizable particles contributing to the particulate organic carbon flux. The topographic constriction sills partially modulated the exchange of oceanic waters (Subantarctic Surface Water) with freshwater river discharges along the Moraleda Channel. This exchange affects salinity and nutrient availability and, thus, the plankton structure. The north microbasin was dominated by a seasonal alternation of the classical (spring) and microbial (winter) food webs. However, in the south microbasin, productivity was low and the system was dominated year-round by large inputs of glacier-derived, silt-rich freshwater carrying predominantly small-sized diatoms ( Skeletonema spp) and bacteria. When superimposed upon this scenario, highly variable (seasonal) solar radiation and photoperiods could exacerbate north-south differences along Moraleda Channel.

Fjord dynamics and glacio-marine interactions on Northern Ellesmere Island, Canada

NASA Astrophysics Data System (ADS)

Hamilton, A.; Mueller, D.; Laval, B.

2012-12-01

Despite the existence of ice shelves and glacier tongues along the northern coast of Ellesmere Island, Canada, for the majority of the past 4000 years (Evans and England, 1992; Antoniades et al., 2011) recent atmospheric warming has contributed to collapse of the remaining ice shelves and the loss of rare ice-shelf dammed lakes (epishelf lakes) (Mueller et al., 2003, 2008; Copland et al., 2007). These studies have primarily addressed surface processes as the causal factors for ice shelf breakup, but changes in ocean stratification and heat flux, meltwater input, and subglacial thermodynamics may strongly influence the integrity and fate of these systems. Despite the growing evidence of the importance of oceanic processes on tidewater glacier mass balance in Greenlandic fjords (Holland et al., 2008; Johnson et al., 2011; Straneo et al., 2011) these processes remain poorly studied on related systems in the Canadian Arctic Archipelago (CAA). In addition, the recent sharp increase in mass loss from the glaciers and ice caps of the CAA, primarily in the form of meltwater runoff (Gardner et al., 2011) suggest understanding the aquatic and oceanic factors contributing to ice shelf and glacier tongue integrity and epishelf lake formation is critical. We will present observations from the Milne Fjord ice shelf, epishelf lake, and glacier tongue system on the northern coast of Ellesmere Island, Canada (Fig. 1). Two years of field observations include a 15-month under-ice ocean mooring deployment, through-ice oceanographic CTD and current velocity profiles, and ice mass balance estimates from ablation stake and GPR surveys. We will present the first ever observations of the seasonal and episodic oceanographic variations of Milne Fjord, with particular focus on ocean-epishelf lake-ice shelf dynamics. We aim to understand how all ice and ocean components interact to determine the evolution and stability of the system, with the goal of understanding and perhaps predicting large ice calving events and epishelf lake drainage. Figure 1. Elevation schematic of Milne Fjord, Ellesmere Island showing the ice shelf-dammed freshwater lake overlying deeper saltwater between the floating ice shelf and glacier tongue. Processes shown include a hypothesized estuarine-like fjord circulation, supra- and sub-glacial runoff, basal ice melting, tides, and sub-ice shelf freshwater outflow.

College Fjord, Prince Williams Sound

NASA Technical Reports Server (NTRS)

2000-01-01

The College Fjord with its glaciers was imaged by ASTER on June 24, 2000.

This image covers an area 20 kilometers (13 miles) wide and 24 kilometers (15 miles) long in three bands of the reflected visible and infrared wavelength region. College Fjord is located in Prince Williams Sound, east of Seward, Alaska. Vegetation is in red, and snow and ice are white and blue. Ice bergs calved off of the glaciers can be seen as white dots in the water. At the head of the fjord, Harvard Glacier (left) is one of the few advancing glaciers in the area; dark streaks on the glacier are medial moraines: rock and dirt that indicate the incorporated margins of merging glaciers. Yale Glacier to the right is retreating, exposing (now vegetated) bedrock where once there was ice. On the west edge of the fjord, several small glaciers enter the water. This fjord is a favorite stop for cruise ships plying Alaska's inland passage.

This image is located at 61.2 degrees north latitude and 147.7 degrees west longitude.

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands Evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance.

Antarctic Peninsula Tidewater Glacier Dynamics

NASA Astrophysics Data System (ADS)

Pettit, E. C.; Scambos, T. A.; Haran, T. M.; Wellner, J. S.; Domack, E. W.; Vernet, M.

2015-12-01

The northern Antarctic Peninsula (nAP, north of 66°S) is a north-south trending mountain range extending transverse across the prevailing westerly winds of the Southern Ocean resulting in an extreme west-to-east precipitation gradient. Snowfall on the west side of the AP is one to two orders of magnitude higher than the east side. This gradient drives short, steep, fast-flowing glaciers into narrow fjords on the west side, while longer lower-sloping glaciers flow down the east side into broader fjord valleys. This pattern in ice dynamics affects ice-ocean interaction on timescales of decades to centuries, and shapes the subglacial topography and submarine bathymetry on timescales of glacial cycles. In our study, we calculate ice flux for the western and eastern nAP using a drainage model that incorporates the modern ice surface topography, the RACMO-2 precipitation estimate, and recent estimates of ice thinning. Our results, coupled with observed rates of ice velocity from InSAR (I. Joughin, personal communication) and Landsat 8 -derived flow rates (this study), provide an estimate of ice thickness and fjord depth in grounded-ice areas for the largest outlet glaciers. East-side glaciers either still terminate in or have recently terminated in ice shelves. Sedimentary evidence from the inner fjords of the western glaciers indicates they had ice shelves during LIA time, and may still have transient floating ice tongues (tabular berg calvings are observed). Although direct oceanographic evidence is limited, the high accumulation rate and rapid ice flux implies cold basal ice for the western nAP glaciers and therefore weak subglacial discharge relative to eastern nAP glaciers and or other tidewater fjord systems such as in Alaska. Finally, despite lower accumulation rates on the east side, the large elongate drainage basins result in a greater ice flux funneled through fewer deeper glaciers. Due to the relation between ice flux and erosion, these east-side glaciers have longer and deeper fjords than the west-side glaciers. These distinct differences between the glaciers of the west and east side of the AP exert a primary control on the differing ice-ocean interactions, grounding-line retreat, and subglacial erosion rates, and provide context to understand rates of nAP ice mass loss.

Using a map-based assessment tool for the development of cost-effective WFD river basin action programmes in a changing climate.

PubMed

Kaspersen, Bjarke Stoltze; Jacobsen, Torsten Vammen; Butts, Michael Brian; Jensen, Niels H; Boegh, Eva; Seaby, Lauren Paige; Müller, Henrik Gioertz; Kjaer, Tyge

2016-08-01

For the 2nd and 3rd river basin management cycles (2015-2027) of the Water Framework Directive (WFD), EU Member States are required to fully integrate climate change into the process of river basin management planning (RBMP). Complying with the main WFD objective of achieving 'good ecological status' in all water bodies in Denmark requires Programmes of Measures (PoMs) to reduce nitrogen (N) pollution from point and diffuse sources. Denmark is among the world's most intensively farmed countries and in spite of thirty years of significant policy actions to reduce diffuse nutrient emissions, there is still a need for further reductions. In addition, the impacts of climate change are projected to lead to a situation where nutrient loads will have to be reduced still further in comparison to current climate conditions. There is an urgent need to address this challenge in WFD action programmes in order to develop robust and cost-effective adaptation strategies for the next WFD RBMP cycles. The aim of this paper is to demonstrate and discuss how a map-based PoMs assessment tool can support the development of adaptive and cost-effective strategies to reduce N losses in the Isefjord and Roskilde Fjord River Basin in the north east of Denmark. The tool facilitates assessments of the application of agri-environmental measures that are targeted towards low retention agricultural areas, where limited or no surface and subsurface N reduction takes place. Effects of climate change on nitrate leaching were evaluated using the dynamic agro-ecosystem model 'Daisy'. Results show that nitrate leaching rates increase by approx. 25% under current management practices. This impact outweighs the expected total N reduction effect of Baseline 2015 and the first RBMP in the case study river basin. The particular PoMs investigated in our study show that WFD N reduction targets can be achieved by targeted land use changes on approx. 4% of the agricultural area under current climate conditions and approx. 9% of the agricultural area, when projected climate change impacts on nitrate leaching rates are included in the assessment. The study highlights the potential of the PoMs assessment tool to assist in evaluation of alternative WFD RBMP scenarios to achieve spatially targeted and cost-effective reductions of N loads at catchment scale in the context of a changing climate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Conceptual PHES-system models of the Aysén watershed and fjord (Southern Chile): testing a brainstorming strategy.

PubMed

Marín, Víctor H; Delgado, Luisa E; Bachmann, Pamela

2008-09-01

The use of brainstorming techniques for the generation of conceptual models, as the basis for the integrated management of physical-ecological-social systems (PHES-systems) is tested and discussed. The methodology is applied in the analysis of the Aysén fjord and watershed (Southern Chilean Coast). Results show that the proposed methods can be adequately used in management scenarios characterized by highly hierarchical, experts/non-experts membership.

Cryostratigraphy, sedimentology, and the late Quaternary evolution of the Zackenberg River delta, northeast Greenland

NASA Astrophysics Data System (ADS)

Gilbert, Graham L.; Cable, Stefanie; Thiel, Christine; Christiansen, Hanne H.; Elberling, Bo

2017-05-01

The Zackenberg River delta is located in northeast Greenland (74°30' N, 20°30' E) at the outlet of the Zackenberg fjord valley. The fjord-valley fill consists of a series of terraced deltaic deposits (ca. 2 km2) formed during relative sea-level (RSL) fall. We investigated the deposits using sedimentological and cryostratigraphic techniques together with optically stimulated luminescence (OSL) dating. We identify four facies associations in sections (4 to 22 m in height) exposed along the modern Zackenberg River and coast. Facies associations relate to (I) overriding glaciers, (II) retreating glaciers and quiescent glaciomarine conditions, (III) delta progradation in a fjord valley, and (IV) fluvial activity and niveo-aeolian processes. Pore, layered, and suspended cryofacies are identified in two 20 m deep ice-bonded sediment cores. The cryofacies distribution, together with low overall ground-ice content, indicates that permafrost is predominately epigenetic in these deposits. Fourteen OSL ages constrain the deposition of the cored deposits to between approximately 13 and 11 ka, immediately following deglaciation. The timing of permafrost aggradation was closely related to delta progradation and began following the subaerial exposure of the delta plain (ca. 11 ka). Our results reveal information concerning the interplay between deglaciation, RSL change, sedimentation, permafrost aggradation, and the timing of these events. These findings have implications for the timing and mode of permafrost aggradation in other fjord valleys in northeast Greenland.

Benthic biodiversity and ecological gradients in the Seno Magdalena (Puyuhuapi Fjord, Chile)

NASA Astrophysics Data System (ADS)

Betti, F.; Bavestrello, G.; Bo, M.; Enrichetti, F.; Loi, A.; Wanderlingh, A.; Pérez-Santos, I.; Daneri, G.

2017-11-01

Due to its complex hydrological, geomorphological and climatic features, the Chilean fjords region is considered among the most productive areas of the world. The benthic fauna of this region accounts for more than 1600 species showing marked latitudinal biogeographic differences characterizing this as one of the most important hotspot of biodiversity of cold-temperate environments. Despite numerous studies have been conducted to depict the biological characteristics of the fjords, the present situation is strongly unbalanced towards specific taxa. Hence, this study takes into consideration a community approach, highlighting the distribution of six benthic assemblages thriving on vertical walls along the Seno Magdalena fjord (Aysen region). Underwater pictures were used to characterize the trends in abundance and diversity of the main taxa showing distinct responses to salinity and turbidity. Among the less tolerant taxa to high fresh water inputs there are encrusting algae, mainly found in the most external sites lashed by outer currents, far from the estuarine plume. The bathymetric zonation of the assemblages, instead, is characterized by a dense mussel belt in the first 10 m, within a thick layer of low-salinity, nutrient-enriched waters. Rich assemblages of sponges, brachiopods, gorgonians and scleractinians thrive in deeper, marine, clear waters. The evaluation of the ecological role of benthic species leads both to the definition of potential bioindicator taxa responding to anthropic disturbances and to the promotion of protected areas.

Spatial and temporal variability in distribution of water masses in Hornsund, Spitsbergen

NASA Astrophysics Data System (ADS)

Promińska, Agnieszka; Falck, Eva; Walczowski, Waldemar; Sundfjord, Arild

2016-04-01

Arctic fjords constitute an important part of many recent investigations because this is the place where different water masses meet, mix, and transform, influencing the stability of glaciers. Hornsund, the southernmost fjord of West Spitsbergen, has been studied during the past 15 years. Observations were based primarily on high resolution measurements of water temperature and salinity along fixed sections, that have been performed every July between 2001-2015. Research carried out in years 2010 - 2015 under Polish - Norwegian projects AWAKE and AWAKE-2 allowed for expansion of the database with data covering the period from spring to autumn. During this time measurements were also conducted from a small boat in the vicinity of glaciers with a time resolution of 1-2 weeks in addition to a mooring system deployed in the fjord and on the shelf just outside Hornsund. Synthesis of our measurements give an overview of water masses observed in the fjord. From summer to summer observations reveal high variability in water temperature and salinity giving a distinct division into an area influenced by oceanic factors (Main Basin) and an area which is more influenced by local factors (Brepollen). The chronology of water mass transformation has been obtained indicating a time of transition between winter (Arctic type), additionally interrupted by temporary inflow of waters of Atlantic origin, and summer (Atlantic type) conditions.

Estimating spring terminus submarine melt rates at a Greenlandic tidewater glacier using satellite imagery

NASA Astrophysics Data System (ADS)

Moyer, Alexis N.; Nienow, Peter W.; Gourmelen, Noel; Sole, Andrew J.; Slater, Donald A.

2017-12-01

Oceanic forcing of the Greenland Ice Sheet is believed to promote widespread thinning at tidewater glaciers, with submarine melting proposed as a potential trigger of increased glacier calving, retreat, and subsequent acceleration. The precise mechanism(s) driving glacier instability, however, remain poorly understood, and while increasing evidence points to the importance of submarine melting, estimates of melt rates are uncertain. Here we estimate submarine melt rate by examining freeboard changes in the seasonal ice tongue of Kangiata Nunaata Sermia at the head of Kangersuneq Fjord, southwest Greenland. We calculate melt rates for March and May 2013 by differencing along-fjord surface elevation, derived from high-resolution TanDEM-X digital elevation models, in combination with ice velocities derived from offset tracking applied to TerraSAR-X imagery. Estimated steady state melt rates reach up to 1.4 ± 0.5 m d^-1 near the glacier grounding line, with mean values of up to 0.8 ± 0.3 and 0.7 ± 0.3 m d^1 for the eastern and western parts of the ice tongue, respectively. Melt rates decrease with distance from the ice front and vary across the fjord. This methodology reveals spatio-temporal variations in submarine melt rates at tidewater glaciers which develop floating termini, and can be used to improve our understanding of ice-ocean interactions and submarine melting in glacial fjords.

Marine benthic habitat mapping of Muir Inlet, Glacier Bay National Park and Preserve, Alaska, with an evaluation of the Coastal and Marine Ecological Classification Standard III

USGS Publications Warehouse

Trusel, Luke D.; Cochrane, Guy R.; Etherington, Lisa L.; Powell, Ross D.; Mayer, Larry A.

2010-01-01

Seafloor geology and potential benthic habitats were mapped in Muir Inlet, Glacier Bay National Park and Preserve, Alaska, using multibeam sonar, ground-truth information, and geological interpretations. Muir Inlet is a recently deglaciated fjord that is under the influence of glacial and paraglacial marine processes. High glacially derived sediment and meltwater fluxes, slope instabilities, and variable bathymetry result in a highly dynamic estuarine environment and benthic ecosystem. We characterize the fjord seafloor and potential benthic habitats using the Coastal and Marine Ecological Classification Standard (CMECS) recently developed by the National Oceanic and Atmospheric Administration (NOAA) and NatureServe. Substrates within Muir Inlet are dominated by mud, derived from the high glacial debris flux. Water-column characteristics are derived from a combination of conductivity temperature depth (CTD) measurements and circulation-model results. We also present modern glaciomarine sediment accumulation data from quantitative differential bathymetry. These data show Muir Inlet is divided into two contrasting environments: a dynamic upper fjord and a relatively static lower fjord. The accompanying maps represent the first publicly available high-resolution bathymetric surveys of Muir Inlet. The results of these analyses serve as a test of the CMECS and as a baseline for continued mapping and correlations among seafloor substrate, benthic habitats, and glaciomarine processes.

Organic carbon sources across salinity gradients in Chilean Fjords: Reloncaví Fjord ( 41°S) and Southern Patagonian ice fields area ( 48°S)

NASA Astrophysics Data System (ADS)

Placencia, Juan; Llanos, Gustavo; Contreras, Sergio

2017-04-01

The organic matter preserved in marine sediments contains contributions of allochthonous and autochthonous and variable source inputs. Allochthonous sources are terrestrial erosion (including anthropogenic material) of relatively labile and refractory material, while autochthonous sources including marine phytoplankton. In order to establish the sources of the organic matter (allochthonous/autochthonous) and how organic carbon is distributed along a salinity gradient, on this study we examined of organic Carbon/Nitrogen molar ratios (C:N), isotopic composition (δ13C) and n-alkanes (n-C24 to n-C34) in surface sediments from two continuous systems: river-fjord-ocean in Northern Patagonia (41°S-43°S), and glacier-fjord-ocean in central Patagonia (47°S-50°S). The continental inner fjord areas are characterized with sediment enriched in allochthonous organic carbon and high C:N (8-12) and low δ13C values (-23‰ to -26‰). Towards the Pacific Ocean, low C:N (6-7) and high δ13C values (-20‰ to -22‰) suggest prevalent autochthonous marine sources. Estuarine waters with salinity between 2 psu and 30 psu were associated with high C:N and low δ13C values together with odd over even long-chain n-alkane predominance (n-C31, n-C29 and n-C27) in surface sediments. All geochemical proxies suggest a great contribution of terrigenous input by glacier origin rivers, mainly from terrestrial plants in both areas. Our study provides a framework to guide future researches on environmental and climate change on these systems. This study was supported by the Chilean Navy's Hydrographic and Oceanographic Service, the Chilean National Oceanographic Committee through the Grants CONA C19F1308 and C20F1404, and the Research Office at Universidad Católica de la Ssma. Concepción.

Organic carbon storage and benthic consumption in sediments of northern fjords (60-80°N)

NASA Astrophysics Data System (ADS)

Włodarska-Kowalczuk, Maria; Zaborska, Agata; Jankowska, Emilia; Mazurkiewicz, Mikołaj

2017-04-01

Fjords have been recently recognized as hotspots of organic carbon storage, with organic carbon burial rates one hundred times larger than the global ocean average, accounting for 11% of global annual marine carbon burial (Smith et al. (2015) Nature Geoscience 8: 450-453). The organic carbon production and processing in coastal waters and sediments are controlled by environmental settings that are likely to be reshaped in the course of the global warming. The fastest and strongest changes are to occur in polar regions. In the present study we compare organic carbon stocks, accumulation and burial in temperate (Raunefjorden, Ullsfjorden, Balsfjorden) and Arctic (Hornsund, Kongsfjorden, Rijpfjorden) fjords located along the latitudinal/thermal gradient from the southern Norway (60 °N) to North of Svalbard (80 °N). The sediment cores were collected at 3 to 5 stations within the central basin at 150-300 m in each fjord during r/v Helmer Hansen and r/v Oceania cruises in 2014 and 2015. Vertical patterns of grain size and organic matter content and sources (Corg concentration, stable isotope δ13C signature, photosynthetic pigments concentration) have been analyzed. Sediment accumulation rates have been estimated with use of 210Pb dating method. Fresh carbon accumulation rate was estimated based on organic carbon concentration is surface sediments and mass sediment accumulation rate. The variability in metazoan productivity and carbon consumption (calculated based on the macro- and meiobenthic species biomass spectra in samples collected at the same stations) was also assessed to explore the patterns of biological controls of carbon storage in sediments. Carbon burial was estimated by multiplying organic carbon concentration in deepest sampled sediments and mass sediment accumulation rate. The effects of contrasting hydrological regimes and biological activity on the carbon storage in the studied fjords are discussed from the perspective of possible effects of climate warming driven changes on the Arctic fjordic sedimentary systems.

On the impact of fjord geometry on grounding line stability

NASA Astrophysics Data System (ADS)

Åkesson, H.; Nick, F. M.; Morlighem, M.; Nisancioglu, K. H.

2016-12-01

Observations and reconstructions of Antarctic and Greenland marine-terminating glaciers and their grounding lines show that their response to external forcings is highly dependent on the geometry of individual glaciers, such as fjord geometry. While recent retreat of these glaciers is broadly consistent with warmer atmospheric and oceanic conditions, we observe considerable spatial and temporal variability, with diverse glacier behavior within the same regions. The relatively short observational record of marine-terminating glaciers also needs to be placed in a long-term context. Reconstructions of marine-terminating glaciers, however, indicate highly asynchronous retreat histories despite being subject to similar climatic forcings. These lines of evidence suggest that regional climate forcing alone cannot explain marine-terminating glacier behavior, and that these glaciers cannot be used uncritically as indicators of past climates because of their heterogeneous response to climate change. Here we use a dynamic flowline model with a physical treatment of iceberg calving to assess the effect of fjord geometry on grounding line stability on decadal and longer time scales. The model includes driving and resistive stresses of ice flow and is applied to idealized fjord geometries representing different real-world glaciers. We find that the geometry can override the signal from the ambient forcing over multiple centuries, resulting in non-linear, rapid grounding line migration. In particular we highlight the importance of fjord width, which has received relatively little attention in terms of marine ice sheet instability. Our findings provide new insights into grounding line behavior and may explain some of the documented heterogeneous, asynchronous patterns of marine-terminating glaciers in Greenland, Antarctica, Alaska and elsewhere. Further, we investigate the geometric influence on the reversibility and hysteresis of grounding line migration, relevant for oscillatory glacier behavior, marine-terminating glacier retreat-advance cycles and Heinrich events. Finally, we present comparative, preliminary results using the 3-dimensional ice sheet model ISSM and discuss our findings in terms of ice shelf stability and buttressing.

Le syndrome d’Usher: à propos d’une observation

PubMed Central

Daoudi, Chama; boutimzine, Noureddine; Haouzi, Samia El; Lezrek, Omar; Tachfouti, Samira; Lezrek, Mounir; Laghmari, Mina; Daoudi, Rajae

2017-01-01

Résumé Le syndrome d'Usher est une maladie génétique comportant une double atteinte sensorielle (auditive et visuelle) appelée surdicécité. Nous rapportons l'observation d'un patient de 50 ans, issue d'un mariage consanguin présentant une surdité congénitale avec une fonction vestibulaire normale et une rétinopathie pigmentaire responsable d'une baisse bilatérale de l'acuité visuelle apparue vers l'âge de 16 ans. Cette association compose le type 2 du syndrome d'Usher, affection rare de transmission autosomique récessive. La chirurgie de la cataracte a permis une amélioration de l'acuité visuelle chez ce patient. PMID:28979619

Interactions of the Greenland Petermann Glacier with the ocean: An initial perspective (Invited)

NASA Astrophysics Data System (ADS)

Falkner, K. K.; Johnson, H. L.; Melling, H.; Muenchow, A.; Samelson, R. M.; Friends Of Petermann

2010-12-01

Petermann Glacier is major outlet glacier that drains 6% of the area of the Greenland Ice Sheet in western North Greenland. It is one of four major outlet glaciers on Greenland with a grounding line substantially below sea level (about 500m) and one of two such glaciers to retain a substantial floating tongue. The floating ice tongue of Petermann glacier is thought to lose at least 80% of its mass through ocean interaction. Based on three opportunistic ocean surveys in Petermann Fjord, we present an overview of circulation at the fjord mouth, hydrographic structure beneath the ice tongue, oceanic heat delivered to the under-ice cavity and the fate of the resulting melt water. We also present an historical perspective on the August 2010 major calving event. The 1100m-deep fjord is separated from neighboring Hall Basin by a sill that is inferred to lie between 350m and 450m deep. Hall Basin is a section of Nares Strait that connects the Arctic Ocean (at the Lincoln Sea proceeding southward through Robeson Channel, Hall Basin, Kennedy Channel, Kane Basin and Smith Sound) to Baffin Bay. Sills in the Lincoln Sea (290m) and in Kane Basin (220m) restrict communication with the Arctic Ocean and Baffin Bay. The net flux of seawater through Nares Strait is southward and relatively fresh, conditioned by sources and processes within the Arctic Ocean and locally. Within Petermann Fjord, glacial melt water appears on the northeast side at 200-600m. A cyclonic gyre occurs within the fjord mouth, with outflow on the northeast side. Oceanic heat fluxes into the fjord are sufficient to account for the observed rate of basal melting. Cold, low salinity water intrudes far under the ice and likely limits basal melting to the inland half of the tongue. The recent major calving event resulted in a loss of 300 km2 or about 20% of the total area of the floating tongue, most of which remained intact as an ice island that garnered much media attention. Available observations show calving to be sporadic on a decadal timescale. Multiple factors likely contribute to calving events. These include the geometry of the fjord, absence of sea ice, preconditioning of the glacier by crevassing and melt related cracking and occurrence of strong katabatic or orographically channeled winds. The recent event falls within the realm of previously documented calving rates but the remaining tongue length is the shortest ever directly observed. Gaps in the 134 year record preclude final judgment about whether the recent calving is entirely unprecedented. Rising surface temperature trends and changed sea ice and ocean circulation patterns in the Arctic could render the tongue susceptible to collapse. As this could contribute to accelerated ice mass flux from Greenland, it is important to continue to observe and clarify processes operative in this system.

The Role of Silicon Limitation in Phytoplankton Phenology in a Sub-Arctic Fjord System

NASA Astrophysics Data System (ADS)

Dobbins, W.; Krause, J. W.; Agustí, S.; Duarte, C. M.; Schulz, I. K.; Winding, M.; Rowe, K. A.; Sejr, M.

2017-12-01

Bacillariophyceae (diatoms) are a significant driver of the biological pump and thus various chemical cycles in high latitude ecosystems. Diatoms have an obligate silicon requirement that has been established as a growth-limiting factor in a variety of ecosystems, and silicon availability likely plays an important role in the temporal evolution of high latitude phytoplankton blooms. However, no previous work has been done to assess the progression of this limitation across a full bloom cycle in the West Greenlandic Nuup Kangerlua fjord or equivalent systems with rapidly evolving land-sea-ice interfaces. Here we provide experimental evidence that the Nuup Kangerlua spring bloom is both diatom driven and strongly silicon constrained. Chlorophyll concentration and growth rates derived from biogenic silica measurements peaked contemporaneously; indicating diatoms were primary members of the phytoplankton assemblage. Moreover, incubation experiments revealed strong biomass increases in response to silicon additions during the bloom period. This work shows silicon availability may play a significant role in bloom phenology in the Nuup Kangerlua fjord.

Archean metamorphic sequence and surfaces, Kangerdlugssuaq Fjord, East Greenland

NASA Technical Reports Server (NTRS)

Kays, M. A.

1986-01-01

The characteristics of Archean metamorphic surfaces and fabrics of a mapped sequence of rocks older than about 3000 Ma provide information basic to an understanding of the structural evolution and metamorphic history in Kangerdlugssuaq Fjord, east Greenland. This information and the additional results of petrologic and geochemical studies have culminated in an extended chronology of Archean plutonic, metamorphic, and tectonic events. The basis for the chronology is considered, especially the nature of the metamorphic fabrics and surfaces in the Archean sequence. The surfaces, which are planar mineral parageneses, may prove to be mappable outside Kangerdlugssuaq Fjord, and if so, will be helpful in extending the events that they represent to other Archean sequences in east Greenland. The surfaces will become especially important reference planes if the absolute ages of their metamorphic assemblages can be determined in at least one location where strain was low subsequent to their recrystallization. Once an isochron is obtained, the dynamothermal age of the regionally identifiable metamorphic surface is determined everywhere it can be mapped.

Boundary condition of grounding lines prior to collapse, Larsen-B Ice Shelf, Antarctica.

PubMed

Rebesco, M; Domack, E; Zgur, F; Lavoie, C; Leventer, A; Brachfeld, S; Willmott, V; Halverson, G; Truffer, M; Scambos, T; Smith, J; Pettit, E

2014-09-12

Grounding zones, where ice sheets transition between resting on bedrock to full floatation, help regulate ice flow. Exposure of the sea floor by the 2002 Larsen-B Ice Shelf collapse allowed detailed morphologic mapping and sampling of the embayment sea floor. Marine geophysical data collected in 2006 reveal a large, arcuate, complex grounding zone sediment system at the front of Crane Fjord. Radiocarbon-constrained chronologies from marine sediment cores indicate loss of ice contact with the bed at this site about 12,000 years ago. Previous studies and morphologic mapping of the fjord suggest that the Crane Glacier grounding zone was well within the fjord before 2002 and did not retreat further until after the ice shelf collapse. This implies that the 2002 Larsen-B Ice Shelf collapse likely was a response to surface warming rather than to grounding zone instability, strengthening the idea that surface processes controlled the disintegration of the Larsen Ice Shelf. Copyright © 2014, American Association for the Advancement of Science.

A Century of Stability of Avannarleq and Kujalleq Glaciers, West Greenland, Explained Using High-Resolution Airborne Gravity and Other Data

NASA Astrophysics Data System (ADS)

An, L.; Rignot, E.; Mouginot, J.; Millan, R.

2018-04-01

The evolution of Greenland glaciers in a warming climate depends on their depth below sea level, flow speed, surface melt, and ocean-induced undercutting at the calving front. We present an innovative mapping of bed topography in the frontal regions of Sermeq Avannarleq and Kujalleq, two major glaciers flowing into the ice-choked Torssukatak Fjord, central west Greenland. The mapping combines a mass conservation algorithm inland, multibeam echo sounding data in the fjord, and high-resolution airborne gravity data at the ice-ocean transition where other approaches have traditionally failed. We obtain a reliable, precision (±40 m) solution for bed topography across the ice-ocean boundary. The results reveal a 700 m deep fjord that abruptly ends on a 100-300 m deep sill along the calving fronts. The shallow sills explain the presence of stranded icebergs, the resilience of the glaciers to ocean-induced undercutting by warm Atlantic water, and their remarkable stability over the past century.

The hyper-enrichment of V and Zn in black shales of the Late Devonian-Early Mississippian Bakken Formation (USA)

USGS Publications Warehouse

Scott, Clinton T.; Slack, John F.; Kelley, Karen Duttweiler

2017-01-01

Black shales of the Late Devonian to Early Mississippian Bakken Formation are characterized by high concentrations of organic carbon and the hyper-enrichment (> 500 to 1000s of mg/kg) of V and Zn. Deposition of black shales resulted from shallow seafloor depths that promoted rapid development of euxinic conditions. Vanadium hyper-enrichments, which are unknown in modern environments, are likely the result of very high levels of dissolved H2S (~ 10 mM) in bottom waters or sediments. Because modern hyper-enrichments of Zn are documented only in Framvaren Fjord (Norway), it is likely that the biogeochemical trigger responsible for Zn hyper-enrichment in Framvaren Fjord was also present in the Bakken basin. With Framvaren Fjord as an analogue, we propose a causal link between the activity of phototrophic sulfide oxidizing bacteria, related to the development of photic-zone euxinia, and the hyper-enrichment of Zn in black shales of the Bakken Formation.

Effect of diet, location and sampling year on bioaccumulation of mercury, selenium and cadmium in pelagic feeding seabirds in Svalbard.

PubMed

Øverjordet, Ida Beathe; Gabrielsen, Geir Wing; Berg, Torunn; Ruus, Anders; Evenset, Anita; Borgå, Katrine; Christensen, Guttorm; Lierhagen, Syverin; Jenssen, Bjørn Munro

2015-03-01

Hepatic concentrations of mercury (Hg), selenium (Se) and cadmium (Cd) were determined in black-legged kittiwakes (Rissa tridactyla) and little auks (Alle alle) from two fjords in Svalbard (Kongsfjorden; 78°57'N, 12°12'E and Liefdefjorden; 79°37'N, 13°20'E). The inflow of Arctic and Atlantic water differs between the two fjords, potentially affecting element accumulation. Trophic positions (TP) were derived from stable nitrogen isotope ratios (δ(15)N), and stable carbon isotope ratios (δ(13)C) were assessed to evaluate the terrestrial influence on element accumulation. Mercury, Cd, TP and δ(13)C varied significantly between locations and years in both species. Trophic position and feeding habits explained Hg and Cd accumulation in kittiwakes, but not in little auks. Biomagnification of Hg and Cd were found in the food webs of both the Atlantic and the Arctic fjord, and no inter-fjord differences were detected. The δ(13)C were higher in the seabirds from Kongsfjorden than in Liefdefjorden, but this did not explain variations in element accumulation. Selenium concentrations were not influenced by Hg accumulation in kittiwakes, indicating baseline levels of Se in this species. In contrast, correlations between Hg and Se and lower Se:Hg ratios in little auks from Kongsfjorden than in Liefdefjorden indicate a more pronounced influence of Se-Hg complex formation in little auks feeding in Atlantic waters. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mapping tide-water glacier dynamics in east Greenland using landsat data

USGS Publications Warehouse

Dwyer, John L.

1995-01-01

Landsat multispectral scanner and thematic mapper images were co-registered For the Kangerdlugssuaq Fjord region in East Greenland and were used to map glacier drainage-basin areas, changes in the positions of tide-water glacier termini and to estimate surface velocities of the larger tide-water glaciers. Statistics were compiled to document distance and area changes to glacier termini. The methodologies developed in this study are broadly applicable to the investigation of tide-water glaciers in other areas. The number of images available for consecutive years and the accuracy with which images are co-registered are key factors that influence the degree to which regional glacier dynamics can be characterized using remotely sensed data.Three domains of glacier state were interpreted: net increase in terminus area in the southern part of the study area, net loss of terminus area for glaciers in upper Kangerdlugssuaq Fjord and a slight loss of glacier terminus area northward from Ryberg Fjord. Local increases in the concentrations of drifting icebergs in the fjords coincide with the observed extension of glacier termini positions Ice-surface velocity estimates were derived for several glaciers using automated image cross-correlation techniques The velocity determined for Kangerdlugssuaq Gletscher is approximately 5.0 km a−1 and that for Kong Christian IV Gletscher is 0.9 km a−1. The continuous presence of icebergs and brash ice in front of these glaciers indicates sustained rates of ice-front calving.

Fine-scale distribution of zooplankton is linked to phytoplankton species composition and abundance in a North Norwegian fjord system

NASA Astrophysics Data System (ADS)

Norrbin, F.; Priou, P. D.; Varela, A. P.

2016-02-01

We studied the influence of dense layers of phytoplankton and aggregates on shaping the vertical distribution of zooplankton in a North Norwegian fjord using a Video Plankton Recorder (VPR). This instrument provided fine-scale vertical distribution (cm-m scale) of planktonic organisms as well as aggregates of marine snow in relation to environmental conditions. At the height - later stage of the spring phytoplankton bloom in May, the outer part of the fjord was dominated by Phaeocystis pouchetii, while diatoms (Chaetoceros spp.) were dominating in the innermost basin. Small copepods species like Pseudocalanus spp., Microsetella norvegica, and Oithona spp. prevailed over larger copepod species in the inner part of the fjord whereas the outer part was dominated by large copepods like Calanus finmarchicus. While the zooplankton where spread out over the water column during the early stage of the bloom, in May they were linked to the phytoplankton vertical distribution and in the winter situation they were found in deeper waters. Herbivorous zooplankton species were affected by phytoplankton species composition; C. finmarchicus and Pseudocalanus spp. avoided the dense layer of P. pouchetii while herbivorous zooplankton matched the distribution of the diatom-dominated bloom. Small, omnivorous copepod species like Microsetella sp., Oithona sp. and Pseudocalanus sp. were often associated with dense layers of snow aggregates. This distribution may provide a shelter from predators as well as a food source. Natural or anthropogenic-induced changes in phytoplankton composition and aggregate distribution may thus influence food-web interactions.

Kittlitz’s and Marbled Murrelets in Kenai Fjords National Park, south-central Alaska: At-sea distribution, abundance, and foraging habitat, 2006–08

USGS Publications Warehouse

Arimitsu, Mayumi L.; Piatt, John F.; Romano, Marc D.; Madison, E.N.; Conaway, Jeffrey S.

2010-01-01

Kittlitz’s murrelets (Brachyramphus brevirostris) and marbled murrelets (B. marmoratus) are small diving seabirds and are of management concern because of population declines in coastal Alaska. In 2006–08, we conducted a study in Kenai Fjords National Park, south-central Alaska, to estimate the recent population size of Brachyramphus murrelets, to evaluate productivity based on juvenile to adult ratios during the fledgling season, and to describe and compare their use of marine habitat. We also attempted a telemetry study to examine Kittlitz’s murrelet nesting habitat requirements and at-sea movements. We estimated that the Kittlitz’s murrelet population was 671 ± 144 birds, and the marbled murrelet population was 5,855 ± 1,163 birds. Kittlitz’s murrelets were limited to the heads of three fjords with tidewater glaciers, whereas marbled murrelets were more widely distributed. Population estimates for both species were lower in 2007 than in 2006 and 2008, possibly because of anomalous oceanographic conditions that may have delayed breeding phenology. During late season surveys, we observed few hatch-year marbled murrelets and only a single hatch-year Kittlitz’s murrelet over the course of the study. Using radio telemetry, we found a likely Kittlitz’s murrelet breeding site on a mountainside bordering one of the fjords. We never observed radio-tagged Kittlitz’s murrelets greater than 10 kilometer from their capture sites, suggesting that their foraging range during breeding is narrow. We observed differences in oceanography between fjords, reflecting differences in sill characteristics and orientation relative to oceanic influence. Acoustic biomass, a proxy for zooplankton and small schooling fish, generally decreased with distance from glaciers in Northwestern Lagoon, but was more variable in Aialik Bay where dense forage fish schools moved into glacial areas late in the summer. Pacific herring (Clupea pallasii), capelin (Mallotus villosus) and Pacific sand lance (Ammodytes hexapterus) were important forage species for murrelets in Kenai Fjords. Euphausiids also may have been an important forage resource for Kittlitz’s murrelets in turbid glacial outflows in shallow waters during daytime. Marbled murrelets generally were more tolerant to a wider range of foraging habitat conditions although they tended to avoid the ice-covered silty waters close to glaciers. In contrast, Kittlitz’s murrelets preferred areas where the influence of tidewater glaciers was the greatest and where their distribution was determined largely by prey availability. This work highlights an important link between interannual variability in murrelet counts at sea and mesoscale oceanographic conditions that influence marine productivity and prey distribution.

Modern sedimentation patterns in Potter Cove, King George Island, Antarctica

NASA Astrophysics Data System (ADS)

Hass, H. Christian; Kuhn, Gerhard; Wölfl, Anne-Cathrin; Wittenberg, Nina; Betzler, Christian

2013-04-01

IMCOAST among a number of other initiatives investigates the modern and the late Holocene environmental development of south King George Island with a strong emphasis on Maxwell Bay and its tributary fjord Potter Cove (maximum water depth: about 200 m). In this part of the project we aim at reconstructing the modern sediment distribution in the inner part of Potter Cove using an acoustic ground discrimination system (RoxAnn) and more than136 ground-truth samples. Over the past 20 years the air temperatures in the immediate working area increased by more than 0.6 K (Schloss et al. 2012) which is less than in other parts of the West Antarctic Peninsula (WAP) but it is still in the range of the recovery of temperatures from the Little Ice Age maximum to the beginning of the 20th century. Potter Cove is a small fjord characterized by a series of moraine ridges produced by a tidewater glacier (Fourcade Glacier). Presumably, the farthest moraine is not much older than about 500 years (LIA maximum), hence the sediment cover is rather thin as evidenced by high resolution seismic data. Since a few years at least the better part of the tidewater glacier retreated onto the island's mainland. It is suggested that such a fundamental change in the fjord's physiography has also changed sedimentation patterns in the area. Potter Cove is characterized by silty-clayey sediments in the deeper inner parts of the cove. Sediments are coarser (fine to coarse sands and boulders) in the shallower areas; they also coarsen from the innermost basin to the mouth of the fjord. Textural structures follow the seabed morphology, i.e. small v-shaped passages through the moraine ridges. The glacier still produces large amounts of turbid melt waters that enter the cove at various places. We presume that very fine-grained sediments fall out from the meltwater plumes and are distributed by mid-depth or even bottom currents, thus suggesting an anti-estuarine circulation pattern. Older sediments that are more distal to the glacier front and sediments in shallower places (e.g. on top of the moraine ridges) become increasingly overprinted by coarser sediments from the shallow areas of the fjord. These areas are prone to wave induced winnowing effects as well as disturbances by ploughing icebergs. It can be concluded that coarsening of the fjord sediments will continue while the supply of fine-grained meltwater sediments might cease due to exhaustion of the reservoirs.

Sedimentary organic matter in two Spitsbergen fjords: Terrestrial and marine contributions based on carbon and nitrogen contents and stable isotopes composition

NASA Astrophysics Data System (ADS)

Koziorowska, Katarzyna; Kuliński, Karol; Pempkowiak, Janusz

2016-02-01

The aim of this study was to estimate the spatial variability of organic carbon (Corg) and total nitrogen (Ntot) concentrations, Corg/Ntot ratios, stable isotopes of carbon and nitrogen (δ13Corg, δ15Ntot) and the proportions of autochthonous and allochtonous organic matter within recently deposited sediments of two Spitsbergen fjords: the Hornsund and the Adventfjord, which are affected to a different degree by the West Spitsbergen Current. Corg concentrations ranged from 1.38% to 1.98% in the Hornsund and from 1.73% to 3.85% in the Adventfjord. In both fjords the highest Corg concentrations were measured at the innermost stations and they decreased towards the mouths of the fjords. This suggests fresh water runoff to be an important source of organic matter (OM) for surface sediments. The results showed that both fjords differ significantly in terms of sedimentary organic matter characteristics. The samples from the Hornsund, except those from the innermost station in the Brepollen, had relatively low Corg/Ntot ratios, all within a narrow range (from 9.7 to 11.3). On the other hand significantly higher Corg/Ntot ratios, varying within a broad range (from 14.6 to 33.0), were measured in the Adventfjord. The samples from the Hornsund were characterized by higher δ13Corg (from -24.90‰ to -23.87‰) and δ15Ntot (from 3.02‰ to 4.93‰) than those from the Adventfjord (-25.94‰ to -24.69‰ and from 0.71‰ to 4.00‰, respectively). This is attributed to a larger proportion of marine organic matter. Using the two end-member approach proportions of terrestrial organic matter were evaluated. Terrestrial OM contribution for the Adventfjord was in the range of 82-83%, while in case of the Hornsund the results were in the range of 69-75%, with the exception of the innermost part of the fjord, where terrestrial organic matter contribution ranged from 80 to 82%. The strong positive correlation between δ13Corg and δ15Ntot was revealed. This was taken as an indicator that fresh, labile organic matter is the base of the trophic pyramid. The conclusion regarding a more complex food web in the Horsund, based on larger δ15Ntot values, is further substantiated by the larger proportion of autochthonous, labile organic matter found in the Hornsund's sediments.

Evaluation of immune and stress status in harbour porpoises (Phocoena phocoena): can hormones and mRNA expression levels serve as indicators to assess stress?

PubMed Central

2013-01-01

Background The harbour porpoise is exposed to increasing pressure caused by anthropogenic activities in its marine environment. Numerous offshore wind farms are planned or under construction in the North and Baltic Seas, which will increase underwater noise during both construction and operation. A better understanding of how anthropogenic impacts affect the behaviour, health, endocrinology, immunology and physiology of the animals is thus needed. The present study compares levels of stress hormones and mRNA expression of cytokines and acute-phase proteins in blood samples of harbour porpoises exposed to different levels of stress during handling, in rehabilitation or permanent human care. Free-ranging harbour porpoises, incidentally caught in pound nets in Denmark, were compared to harbour porpoises in rehabilitation at SOS Dolfijn in Harderwijk, the Netherlands, and individuals permanently kept in human care in the Dolfinarium Harderwijk and Fjord & Belt Kerteminde, Denmark. Blood samples were investigated for catecholamines, adrenaline, noradrenaline and dopamine, as well as for adrenocorticotropic hormone (ACTH), cortisol, metanephrine and normetanephrine. mRNA expression levels of relevant cell mediators (cytokines IL-10 and TNFα, acute-phase proteins haptoglobin and C-reactive protein and the heat shock protein HSP70) were measured using real-time PCR. Results Biomarker expression levels varied between free-ranging animals and porpoises in human care. Hormone and cytokine ranges showed correlations to each other and to the health status of investigated harbour porpoises. Hormone concentrations were higher in free-ranging harbour porpoises than in animals in human care. Adrenaline can be used as a parameter for the initial reaction to acute stress situations; noradrenaline, dopamine, ACTH and cortisol are more likely indicators for the following minutes of acute stress. There is evidence for different correlations between production of normetanephrine, metanephrine, cortisol and the expression of IL-10, HSP70 and haptoglobin. Conclusions The expression patterns of the selected molecular biomarkers of the immune system are promising to reflect the health and immune status of the harbour porpoise under different levels of stress. PMID:23866055

Late-Quaternary glacial to postglacial sedimentation in three adjacent fjord-lakes of the Québec North Shore (eastern Canadian Shield)

NASA Astrophysics Data System (ADS)

Poiré, Antoine G.; Lajeunesse, Patrick; Normandeau, Alexandre; Francus, Pierre; St-Onge, Guillaume; Nzekwe, Obinna P.

2018-04-01

High-resolution swath bathymetry imagery allowed mapping in great detail the sublacustrine geomorphology of lakes Pentecôte, Walker and Pasteur, three deep adjacent fjord-lakes of the Québec North Shore (eastern Canada). These sedimentary basins have been glacio-isostatically uplifted to form deep steep-sided elongated lakes. Their key geographical position and limnogeological characteristics typical of fjords suggest exceptional potential for long-term high-resolution paleoenvironmental reconstitutions. Acoustic subbottom profiles acquired using a bi-frequency Chirp echosounder (3.5 & 12 kHz), together with cm- and m-long sediment core data, reveal the presence of four acoustic stratigraphic units. The acoustic basement (Unit 1) represents the structural bedrock and/or the ice-contact sediments of the Laurentide Ice Sheet and reveals V-shaped bedrock valleys at the bottom of the lakes occupied by ice-loaded sediments in a basin-fill geometry (Unit 2). Moraines observed at the bottom of lakes and in their structural valleys indicate a deglaciation punctuated by short-term ice margin stabilizations. Following ice retreat and their isolation, the fjord-lakes were filled by a thick draping sequence of rhythmically laminated silts and clays (Unit 3) deposited during glaciomarine and/or glaciolacustrine settings. These sediments were episodically disturbed by mass-movements during deglaciation due to glacial-isostatic rebound. AMS 14C dating reveal that the transition between deglaciation of the lakes Pentecôte and Walker watersheds and the development of para- and post-glacial conditions occurred around 8000 cal BP. The development of the lake-head river delta plain during the Holocene provided a constant source of fluvial sediment supply to the lakes and the formation of turbidity current bedforms on the sublacustrine delta slopes. The upper sediment succession (i.e., ∼4-∼6.5 m) consists of a continuous para-to post-glacial sediment drape (Unit 4) that contains laminated and massive sediment and series of Rapidly Deposited Layers. These results allow establishing a conceptual model of how a glaciated coastal fjord evolves during and after deglaciation in a context of rapid glacio-isostatically induced forced regression.

Object-Based Image Classification of Floating Ice Used as Habitat for Harbor Seals in a Tidewater Glacier Fjord in Alaska

NASA Astrophysics Data System (ADS)

McNabb, R. W.; Womble, J. N.; Prakash, A.; Gens, R.; Ver Hoef, J.

2014-12-01

Tidewater glaciers play an important role in many landscape and ecosystem processes in fjords, terminating in the sea and calving icebergs and discharging meltwater directly into the ocean. Tidewater glaciers provide floating ice for use as habitat for harbor seals (Phoca vitulina richardii) for resting, pupping, nursing, molting, and avoiding predators. Tidewater glaciers are found in high concentrations in Southeast and Southcentral Alaska; currently, many of these glaciers are retreating or have stabilized in a retracted state, raising questions about the future availability of ice in these fjords as habitat for seals. Our primary objective is to investigate the relationship between harbor seal distribution and ice availability at an advancing tidewater glacier in Johns Hopkins Inlet, Glacier Bay National Park, Alaska. To this end, we use a combination of visible and infrared aerial photographs, object-based image analysis (OBIA), and statistical modeling techniques. We have developed a workflow to automate the processing of the imagery and the classification of the fjordscape (e.g., individual icebergs, brash ice, and open water), providing quantitative information on ice coverage as well as properties not typically found in traditional pixel-based classification techniques, such as block angularity and seal density across the fjord. Reflectance variation in the red channel of the optical images has proven to be the most important first-level criterion to separate open water from floating ice. This first-level criterion works well in areas without dense brash ice, but tends to misclassify dense brash ice as single icebergs. Isolating these large misclassified regions and applying a higher reflectance threshold as a second-level criterion helps to isolate individual ice blocks surrounded by dense brash ice. We present classification results from surveys taken during June and August, 2007-2013, as well as preliminary results from statistical modeling of the spatio-temporal distribution of seals and ice. OBIA is a powerful method of habitat classification and offers an effective approach to compare the spatio-temporal distribution and availability of glacial ice habitats for harbor seals in tidewater glacial fjords.

Sedimentology and geomorphology of a large tsunamigenic landslide, Taan Fiord, Alaska

NASA Astrophysics Data System (ADS)

Dufresne, A.; Geertsema, M.; Shugar, D. H.; Koppes, M.; Higman, B.; Haeussler, P. J.; Stark, C.; Venditti, J. G.; Bonno, D.; Larsen, C.; Gulick, S. P. S.; McCall, N.; Walton, M.; Loso, M. G.; Willis, M. J.

2018-02-01

On 17 October 2015, a landslide of roughly 60 × 106 m3 occurred at the terminus of Tyndall Glacier in Taan Fiord, southeastern Alaska. It caused a tsunami that inundated an area over 20 km2, whereas the landslide debris itself deposited within a much smaller area of approximately 2 km2. It is a unique event in that the landslide debris was deposited into three very different environments: on the glacier surface, on land, and in the marine waters of the fjord. Part of the debris traversed the width of the fjord and re-emerged onto land, depositing coherent hummocks with preserved source stratigraphy on an alluvial fan and adjacent moraines on the far side of the fjord. Imagery from before the landslide shows that the catastrophic slope failure was preceded by deformation and sliding for at least the two decades since the glacier retreated to its current terminus location, exposing steep and extensively faulted slopes. A small volume of the total slide mass remains within the source area and is topped by striated blocks (> 10 m across) and standing trees that were transported down the slope in intact positions during the landslide. Field work was carried out in the summer of 2016, and by the time this paper was written, almost all of the supraglacial debris was advected into the fjord and half the subaerial hummocks were buried by glacial advance; this rapid change illustrates how highly active sedimentary processes in high-altitude glacial settings can skew any landslide-frequency analyses, and emphasizes the need for timely field investigations of these natural hazards.

A multiproxy fjord sediment record of Holocene climate change from the subantarctic Auckland Islands

NASA Astrophysics Data System (ADS)

Browne, I. M.; Moy, C. M.; Wilson, G. S.; Neil, H.; Riesselman, C. R.

2014-12-01

The Southern Hemisphere Westerly Winds (SHWW) and the associated oceanic fronts have a major influence on atmospheric and oceanic circulation in the Southern Hemisphere. Sediment cores recovered from fjords along the eastern margin of the sub-Antarctic Auckland Islands (51°S, 166°E) are ideally located to sensitively record changes in the strength and position of the SHWW throughout the Holocene. A 5.75m core from Hanfield Inlet preserves both marine and terrestrial environmental components, which we use to develop a multiproxy record of past climatic conditions. This core, composed entirely of brown marine mud and silt, was recovered from a depth of 44m. Based on the entrance sill depth of the fjord (10mbsl) and our knowledge of regional sea level rise, we infer that the base of the core will be early Holocene in age, which will be confirmed using radiocarbon age dating. Benthic foraminiferal assemblages (125-500μm fraction) in surface and downcore samples are dominated by three taxa, Nonionellina flemingi, Cassidulina carinata and Quinqueloculina seminula. These species are either shallow infaunal or infaunal. We will use stable carbon (δ¹³C) and oxygen (δ¹⁸O) isotope geochemistry of the benthic foraminifera Nonionellina flemingi, Bolivina cf. earlandi, Trifarina angulosa, Bulimina marginata f. marginata and Cibicides species (all identified from Rose Bengal stained box-core samples) to reconstruct water column fluctuations associated with frontal migration. These results will compliment bulk sediment C and N concentration and isotope reconstructions of terrestrial organic matter delivery to fjord sub-basins over the past 12,000 years.

Heavy metal contamination of a Greenland Fjord system by mine wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loring, D.H.; Asmund, G.

Since 1973, about 500,000 tons/yr of metal-rich particulate tailings from a lead/zinc flotation mill have been discharged through a submarine outfall into a two-fjord system on the west coast of Greenland. Differential solubilization of particulate metals by seawater, seasonal water mixing, and sill exchange tailings dispersal processes have resulted in high, but seasonally variable, Zn, Cd, and Pb contamination of the water and suspended particulate matter (SPM). Chemical partition of the SPM shows that most of the Pb, but relatively low proportions of Zn and Cd are weakly bound to the SPM. Such particulate metal characteristics allow the real timemore » effects of tailings discharges and dispersal on the system to be traced even in the sediments where tailings accumulation is very slow. Fjord seaweeds and blue mussels also contain varying amounts of Zn, Pb, and Cd, depending on the metal and their location relative to the tailings outfall. They apparently responded almost instantly to the metal contamination as did the water and SPM. High Pb concentrations in the fjord mussels most likely derive from the preferential uptake of available particulate Pb, whereas the seaweeds appear to derive most of their heavy metal concentrations from the dissolved phase. The evidence from this and other sites, and from experimental work, indicates that any discharge of Pb-particles into the marine environment, either directly as mine wastes or indirectly from natural runoff from current and former lead mining sites, results in immediate lead contamination of the in situ mussel population. 20 refs., 4 figs., 5 tab.« less

Benthic foraminifera contribution to fjord modern carbon pools: A seasonal study in Adventfjorden, Spitsbergen.

PubMed

Pawłowska, J; Łącka, M; Kucharska, M; Szymańska, N; Koziorowska, K; Kuliński, K; Zajączkowski, M

2017-09-01

The aim of this study was to determine the amount of organic and inorganic carbon in foraminifera specimens and to provide quantitative data on the contribution of foraminifera to the sedimentary carbon pool in Adventfjorden. The investigation was based on three calcareous species that occur commonly in Svalbard fjords: Cassidulina reniforme, Elphidium excavatum and Nonionellina labradorica. Our results show that the species investigated did not contribute substantially to the organic carbon pool in Adventfjorden, because they represented only 0.37% of the organic carbon in the sediment. However, foraminiferal biomass could have been underestimated as it did not include arenaceous or monothalamous taxa. Foraminiferal carbonate constituted up to 38% of the inorganic carbon in the sediment, which supports the assumption that in fjords where non-calcifying organisms dominate the benthic fauna foraminifera are among the major producers of calcium carbonate and that they play crucial roles in the carbon burial process. The results presented in this study contribute to estimations of changes in foraminiferal carbon levels in contemporary environments and could be an important reference for palaeoceanographic studies. © 2017 John Wiley & Sons Ltd.

Large bedrock slope failures in a British Columbia, Canada fjord: first documented submarine sackungen

NASA Astrophysics Data System (ADS)

Conway, Kim W.; Vaughn Barrie, J.

2018-01-01

Very large (>60×106 m3) sackungen or deep-seated gravitational slope deformations occur below sea level along a steep fjord wall in central Douglas Channel, British Columbia. The massive bedrock blocks were mobile between 13 and 11.5 thousand radiocarbon years BP (15,800 and 13,400 BP) immediately following deglaciation. Deformation of fjord sediments is apparent in sedimentary units overlying and adjacent to the blocks. Faults bound the edges of each block, cutting the glacial section but not the Holocene sediments. Retrogressive slides, small inset landslides as well as incipient and older slides are found on and around the large failure blocks. Lineations, fractures and faults parallel the coastline of Douglas Channel along the shoreline of the study area. Topographic data onshore indicate that faults and joints demarcate discrete rhomboid-shaped blocks which controlled the form, size and location of the sackungen. The described submarine sackungen share characteristic geomorphic features with many montane occurrences, such as uphill-facing scarps, foliated bedrock composition, largely vertical dislocation and a deglacial timing of development.

Large bedrock slope failures in a British Columbia, Canada fjord: first documented submarine sackungen

NASA Astrophysics Data System (ADS)

Conway, Kim W.; Vaughn Barrie, J.

2018-06-01

Very large (>60×106 m3) sackungen or deep-seated gravitational slope deformations occur below sea level along a steep fjord wall in central Douglas Channel, British Columbia. The massive bedrock blocks were mobile between 13 and 11.5 thousand radiocarbon years BP (15,800 and 13,400 BP) immediately following deglaciation. Deformation of fjord sediments is apparent in sedimentary units overlying and adjacent to the blocks. Faults bound the edges of each block, cutting the glacial section but not the Holocene sediments. Retrogressive slides, small inset landslides as well as incipient and older slides are found on and around the large failure blocks. Lineations, fractures and faults parallel the coastline of Douglas Channel along the shoreline of the study area. Topographic data onshore indicate that faults and joints demarcate discrete rhomboid-shaped blocks which controlled the form, size and location of the sackungen. The described submarine sackungen share characteristic geomorphic features with many montane occurrences, such as uphill-facing scarps, foliated bedrock composition, largely vertical dislocation and a deglacial timing of development.

Geodetic Imaging and Tsunami Modeling of the 2017 Coupled Landslide-Tsunami Event in Karrat Fjord, West Greenland.

NASA Astrophysics Data System (ADS)

Barba, M.; Willis, M. J.; Tiampo, K. F.; Lynett, P. J.; Mätzler, E.; Thorsøe, K.; Higman, B. M.; Thompson, J. A.; Morin, P. J.

2017-12-01

We use a combination of geodetic imaging techniques and modelling efforts to examine the June 2017 Karrat Fjord, West Greenland, landslide and tsunami event. Our efforts include analysis of pre-cursor motions extracted from Sentinal SAR interferometry that we improved with high-resolution Digital Surface Models derived from commercial imagery and geo-coded Structure from Motion analyses. We produce well constrained estimates of landslide volume through DSM differencing by improving the ArcticDEM coverage of the region, and provide modeled tsunami run-up estimates at villages around the region, constrained with in-situ observations provided by the Greenlandic authorities. Estimates of run-up at unoccupied coasts are derived using a blend of high resolution imagery and elevation models. We further detail post-failure slope stability for areas of interest around the Karrat Fjord region. Warming trends in the region from model and satellite analysis are combined with optical imagery to ascertain whether the influence of melting permafrost and the formation of small springs on a slight bench on the mountainside that eventually failed can be used as indicators of future events.

Oxygen intrusion into anoxic fjords leads to increased methylmercury availability

NASA Astrophysics Data System (ADS)

Veiteberg Braaten, Hans Fredrik; Pakhomova, Svetlana; Yakushev, Evgeniy

2013-04-01

Mercury (Hg) appears in the oxic surface waters of the oceans at low levels (sub ng/L). Because inorganic Hg can be methylated into the toxic and bioaccumulative specie methylmercury (MeHg) levels can be high at the top of the marine food chain. Even though marine sea food is considered the main risk driver for MeHg exposure to people most research up to date has focused on Hg methylation processes in freshwater systems. This study identifies the mechanisms driving formation of MeHg during oxygen depletion in fjords, and shows how MeHg is made available in the surface water during oxygen intrusion. Studies of the biogeochemical structure in the water column of the Norwegian fjord Hunnbunn were performed in 2009, 2011 and 2012. In autumn of 2011 mixing flushing events were observed and lead to both positive and negative effects on the ecosystem state in the fjord. The oxygenated water intrusions lead to a decrease of the deep layer concentrations of hydrogen sulfide (H2S), ammonia and phosphate. On the other hand the intrusion also raised the H2S boundary from 8 m to a shallower depth of just 4 m. Following the intrusion was also observed an increase at shallower depths of nutrients combined with a decrease of pH. Before flushing events were observed concentrations of total Hg (TotHg) increased from 1.3 - 1.7 ng/L in the surface layer of the fjord to concentrations ranging from 5.2 ng/L to 6.4 ng/L in the anoxic zone. MeHg increased regularly from 0.04 ng/L in the surface water to a maximum concentration of 5.2 ng/L in the deeper layers. This corresponds to an amount of TotHg present as MeHg ranging from 2.1 % to 99 %. The higher concentrations of MeHg in the deeper layer corresponds to an area where no oxygen is present and concentrations of H2S exceeds 500 µM, suggesting a production of MeHg in the anoxic area as a result of sulphate reducing bacteria activity. After flushing the concentrations of TotHg showed a similar pattern ranging from 0.6 ng/L in the surface layer to 6.5 ng/L at maximum depth (10 m). However, the pattern of MeHg concentrations in the water column changed with relatively high concentrations present already at 4.5 m depth (2.2 ng/L). The environmental consequence of this oxygen intrusion is the appearance in shallower water of toxic MeHg formed in the anoxic layer. As a result of this, MeHg can possibly undergo transport from the anoxic fjord to the surrounding areas.

Mesozooplankton community development at elevated CO2 concentrations: results from a mesocosm experiment in an Arctic fjord

NASA Astrophysics Data System (ADS)

Niehoff, B.; Schmithüsen, T.; Knüppel, N.; Daase, M.; Czerny, J.; Boxhammer, T.

2013-03-01

The increasing CO2 concentration in the atmosphere caused by burning fossil fuels leads to increasing pCO2 and decreasing pH in the world ocean. These changes may have severe consequences for marine biota, especially in cold-water ecosystems due to higher solubility of CO2. However, studies on the response of mesozooplankton communities to elevated CO2 are still lacking. In order to test whether abundance and taxonomic composition change with pCO2, we have sampled nine mesocosms, which were deployed in Kongsfjorden, an Arctic fjord at Svalbard, and were adjusted to eight CO2 concentrations, initially ranging from 185 μatm to 1420 μatm. Vertical net hauls were taken weekly over about one month with an Apstein net (55 μm mesh size) in all mesocosms and the surrounding fjord. In addition, sediment trap samples, taken every second day in the mesocosms, were analysed to account for losses due to vertical migration and mortality. The taxonomic analysis revealed that meroplanktonic larvae (Cirripedia, Polychaeta, Bivalvia, Gastropoda, and Decapoda) dominated in the mesocosms while copepods (Calanus spp., Oithona similis, Acartia longiremis and Microsetella norvegica) were found in lower abundances. In the fjord copepods prevailed for most of our study. With time, abundance and taxonomic composition developed similarly in all mesocosms and the pCO2 had no significant effect on the overall community structure. Also, we did not find significant relationships between the pCO2 level and the abundance of single taxa. Changes in heterogeneous communities are, however, difficult to detect, and the exposure to elevated pCO2 was relatively short. We therefore suggest that future mesocosm experiments should be run for longer periods.

Quantifying ocean and ice sheet contributions to nutrient fluxes in Sermilik Fjord, Southeast Greenland

NASA Astrophysics Data System (ADS)

Cape, M. R.; Straneo, F.; Beaird, N.; Bundy, R.; Charette, M. A.

2016-12-01

Meltwater discharged at the margins of the Greenland Ice Sheet (GrIS) represents a potential source of nutrients to biological communities downstream. In Greenland's glacial fjords, this discharge occurs at depth below and along the face of deeply grounded marine-terminating glaciers. This process drives vigorous circulation and mixing between melt and ambient waters at the ice-ocean margins, giving rise to a new glacially modified water mass (GMW) which constitutes the primary vehicle for transport of meltwater in the marine environment. While previous field studies have noted nutrient enrichment in GMW with respect to unmodified waters along the shelf, the source of this enrichment, whether due to entrainment of deep ambient waters or input by meltwater, remains poorly understood. This knowledge is however critical in order to evaluate the current and future contributions of the GrIS to marine biogeochemical cycling. Here we shed light on the distribution, composition, and properties of GMW along the GrIS margin by analyzing integrated physical and chemical measurements collected in August 2015 in Sermilik Fjord, a major glacial freshwater export pathway. Our results document up to a doubling of nutrient concentrations (nitrate, silicate, phosphate, and iron) in GMW, which is distributed in the top 300 m of the water column throughout the fjord. Partitioning of ocean and ice sheet contributions to GMW nutrient load demonstrates that upwelled waters are the primary source of macro-nutrients to GMW. We expand on these results to discuss the magnitude of fluxes in context of previous observations along the GrIS margins, export pathways of GMW to the shelf, and knowledge gaps needed to be addressed to better constrain ice sheet contributions to marine ecosystem processes.

Shoreline changes and its impact on archaeological sites in West Greenland

NASA Astrophysics Data System (ADS)

Fenger-Nielsen, R.; Kroon, A.; Elberling, B.; Hollesen, J.

2017-12-01

Coastal erosion is regarded as a major threat to archaeological sites in the Arctic region. The problem arises because the predominantly marine-focused lifeways of Arctic people means that the majority of archaeological sites are found near the coast. On a Pan-Arctic scale, coastal erosion is often explained by long-term processes such as sea level rise, lengthening of open water periods due to a decline in sea ice, and a predicted increase in the frequency of major storms. However, on a local scale other short-term processes may be important parameters determining the coastal development. In this study, we focus on the Nuuk fjord system in West Greenland, which has been inhabited over the past 4000 years by different cultures and holds around 260 registered archaeological settlements. The fjord is characterized by its large branching of narrow deep-water and well-shaded water bodies, where tidal processes and local sources of sediment supply by rivers are observed to be the dominant factors determining the coastal development. We present a regional model showing the vulnerability of the shoreline and archeological sites due to coastal processes. The model is based on a) levelling surveys and historical aerial photographs of nine specific sites distributed in the region, b) water level measurements at three sites representing the inner-, middle- and outer fjord system, c) aerial photographs, satellite images and meteorological data of the entire region used to up-scale our local information at a specific settlement scale towards a regional scale. This deals with spatial and temporal variability in erosion and accumulation patterns along the shores in fjords and open seas.

A winter dinoflagellate bloom drives high rates of primary production in a Patagonian fjord ecosystem

NASA Astrophysics Data System (ADS)

Montero, P.; Pérez-Santos, I.; Daneri, G.; Gutiérrez, M. H.; Igor, G.; Seguel, R.; Purdie, D.; Crawford, D. W.

2017-12-01

A dense winter bloom of the dinoflagellate Heterocapsa triquetra was observed at a fixed station (44°35.3‧S; 72°43.6‧W) in the Puyuhuapi Fjord in Chilean Patagonia during July 2015. H. triquetra dominated the phytoplankton community in the surface waters between 2 and 15 m (13-58 × 109 cell m-2), with abundances some 3 to 15 times higher than the total abundance of the diatom assemblage, which was dominated by Skeletonema spp. The high abundance of dinoflagellates was reflected in high rates of gross primary production (GPP; 0.6-1.6 g C m-2 d-1) and chlorophyll-a concentration (Chl-a; 70-199.2 mg m-2) that are comparable to levels reported in spring diatom blooms in similar Patagonian fjords. We identify the main forcing factors behind a pulse of organic matter production during the non-productive winter season, and test the hypothesis that low irradiance levels are a key factor limiting phytoplankton blooms and subsequent productivity during winter. Principal Component Analysis (PCA) indicated that GPP rates were significantly correlated (r = -0.8, p < 0.05) with a decrease in salinity/temperature and the presence of the Heterocapsa bloom. The bloom occurred under low surface irradiance levels characteristic of austral winter and was accompanied by strong northern winds, associated with the passage of a low-pressure system, and a water column dominated by double diffusive layering. To our knowledge, this is the first report of a dense dinoflagellate bloom during deep austral winter in a Patagonian fjord, and our data challenge the paradigm of light limitation as a factor controlling phytoplankton blooms in this region in winter.

Patterns of extracellular enzyme activities and microbial metabolism in an Arctic fjord of Svalbard and in the northern Gulf of Mexico: contrasts in carbon processing by pelagic microbial communities

PubMed Central

Arnosti, Carol; Steen, Andrew D.

2013-01-01

The microbial community composition of polar and temperate ocean waters differs substantially, but the potential functional consequences of these differences are largely unexplored. We measured bacterial production, glucose metabolism, and the abilities of microbial communities to hydrolyze a range of polysaccharides in an Arctic fjord of Svalbard (Smeerenburg Fjord), and thus to initiate remineralization of high-molecular weight organic matter. We compared these data with similar measurements previously carried out in the northern Gulf of Mexico in order to investigate whether differences in the spectrum of enzyme activities measurable in Arctic and temperate environments are reflected in “downstream” aspects of microbial metabolism (metabolism of monomers and biomass production). Only four of six polysaccharide substrates were hydrolyzed in Smeerenburg Fjord; all were hydrolyzed in the upper water column of the Gulf. These patterns are consistent on an interannual basis. Bacterial protein production was comparable at both locations, but the pathways of glucose utilization differed. Glucose incorporation rate constants were comparatively higher in Svalbard, but glucose respiration rate constants were higher in surface waters of the Gulf. As a result, at the time of sampling ca. 75% of the glucose was incorporated into biomass in Svalbard, but in the northern Gulf of Mexico most of the glucose was respired to CO2. A limited range of enzyme activities is therefore not a sign of a dormant community or one unable to further process substrates resulting from extracellular enzymatic hydrolysis. The ultimate fate of carbohydrates in marine waters, however, is strongly dependent upon the specific capabilities of heterotrophic microbial communities in these disparate environments. PMID:24198812

A Management Tool for Assessing Aquaculture Environmental Impacts in Chilean Patagonian Fjords: Integrating Hydrodynamic and Pellets Dispersion Models

NASA Astrophysics Data System (ADS)

Tironi, Antonio; Marin, Víctor H.; Campuzano, Francisco J.

2010-05-01

This article introduces a management tool for salmon farming, with a scope in the local sustainability of salmon aquaculture of the Aysen Fjord, Chilean Patagonia. Based on Integrated Coastal Zone Management (ICZM) principles, the tool combines a large 3-level nested hydrodynamic model, a particle tracking module and a GIS application into an assessment tool for particulate waste dispersal of salmon farming activities. The model offers an open source alternative to particulate waste modeling and evaluation, contributing with valuable information for local decision makers in the process of locating new facilities and monitoring stations.

Controlled artificial upwelling in a fjord to combat toxic algae

NASA Astrophysics Data System (ADS)

McClimans, T. A.; Hansen, A. H.; Fredheim, A.; Lien, E.; Reitan, K. I.

2003-04-01

During the summer, primary production in the surface layers of some fjords depletes the nutrients to the degree that some arts of toxic algae dominate the flora. We describe an experiment employing a bubble curtain to lift significant amounts of nutrient-rich seawater to the light zone and provide an environment in which useful algae can survive. The motivation for the experiment is to provide a local region in which mussels can be cleansed from the effects of toxic algae. Three 100-m long, perforated pipes were suspended at 40 m depth in the Arnafjord, a side arm of the Sognefjord. Large amounts of compressed air were supplied during a period of three weeks. The deeper water mixed with the surface water and flowed from the mixing region at 5 to 15 m depth. Within a few days, the mixture of nutrient-rich water covered most of the inner portion of Arnafjord. Within 10 days, the plankton samples showed that the artificial upwelling produced the desired type of algae and excluded the toxic blooms that were occurring outside the manipulated fjord arm. The project (DETOX) is supported by the Norwegian ministries of Fisheries, Agriculture and Public Administration.

A coupled physical-biological pelagic model of a shallow sill fjord

NASA Astrophysics Data System (ADS)

Aksnes, Dag L.; Lie, Ulf

1990-10-01

A vertically resolved model for the land-locked fjord Lindåspollene, western Norway is presented. Salinity, temperature, oxygen, nitrogen-nutrients, silicate, and two groups of phytoplankton and herbivores are represented as dynamic variables. From 'below' the model is driven by solar radiation, precipitation, wind and tidal exchange and from 'above' by herbivore mortality. Simulation results are presented and discussed together with actual observations from Lindåspollene. The main seasonal and vertical characteristics of the phytoplankton and herbivore dynamics seem to be well reflected by the model, and realistic seasonal patterns may be produced for several successive years. The most characteristic vertical features are the formation of a summer surface production maximum and a deep chlorophyll maximum. Furthermore, a herbivore biomass which develops in the surface layer divides into a shallow and a deep component during summer and becomes concentrated in the surface layer again in the autumn. The nutricline and the pycnocline develop independently of one another, with consequences for the supply of nutrients to the upper euphotic zone. The bottom-up control exerted by the meteorological forcing, especially the freshwater runoff, seems to be of paramount significance for the observed vertical structure and seasonality of the present fjord system.

Partitioning of organic carbon among density fractions in surface sediments of Fiordland, New Zealand

NASA Astrophysics Data System (ADS)

Cui, Xingqian; Bianchi, Thomas S.; Hutchings, Jack A.; Savage, Candida; Curtis, Jason H.

2016-03-01

Transport of particles plays a major role in redistributing organic carbon (OC) along coastal regions. In particular, the global importance of fjords as sites of carbon burial has recently been shown to be even more important than previously thought. In this study, we used six surface sediments from Fiordland, New Zealand, to investigate the transport of particles and OC based on density fractionation. Bulk, biomarker, and principle component analysis were applied to density fractions with ranges of <1.6, 1.6-2.0, 2.0-2.5, and >2.5 g cm-3. Our results found various patterns of OC partitioning at different locations along fjords, likely due to selective transport of higher density but smaller size particles along fjord head-to-mouth transects. We also found preferential leaching of certain biomarkers (e.g., lignin) over others (e.g., fatty acids) during the density fractionation procedure, which altered lignin-based degradation indices. Finally, our results indicated various patterns of OC partitioning on density fractions among different coastal systems. We further propose that a combination of particle size-density fractionation is needed to better understand transport and distribution of particles and OC.

Greenland iceberg melt variability from high-resolution satellite observations

NASA Astrophysics Data System (ADS)

Enderlin, Ellyn M.; Carrigan, Caroline J.; Kochtitzky, William H.; Cuadros, Alexandra; Moon, Twila; Hamilton, Gordon S.

2018-02-01

Iceberg discharge from the Greenland Ice Sheet accounts for up to half of the freshwater flux to surrounding fjords and ocean basins, yet the spatial distribution of iceberg meltwater fluxes is poorly understood. One of the primary limitations for mapping iceberg meltwater fluxes, and changes over time, is the dearth of iceberg submarine melt rate estimates. Here we use a remote sensing approach to estimate submarine melt rates during 2011-2016 for 637 icebergs discharged from seven marine-terminating glaciers fringing the Greenland Ice Sheet. We find that spatial variations in iceberg melt rates generally follow expected patterns based on hydrographic observations, including a decrease in melt rate with latitude and an increase in melt rate with iceberg draft. However, we find no longitudinal variations in melt rates within individual fjords. We do not resolve coherent seasonal to interannual patterns in melt rates across all study sites, though we attribute a 4-fold melt rate increase from March to April 2011 near Jakobshavn Isbræ to fjord circulation changes induced by the seasonal onset of iceberg calving. Overall, our results suggest that remotely sensed iceberg melt rates can be used to characterize spatial and temporal variations in oceanic forcing near often inaccessible marine-terminating glaciers.

Spatial distribution of juvenile and adult female Tanner crabs (Chionoecetes bairdi) in a glacial fjord ecosystem: Implications for recruitment processes

USGS Publications Warehouse

Nielsen, J.K.; Taggart, S. James; Shirley, Thomas C.; Mondragon, Jennifer

2007-01-01

A systematic pot survey in Glacier Bay, Alaska, was conducted to characterize the spatial distribution of juvenile and adult female Tanner crabs, and their association with depth and temperature. The information was used to infer important recruitment processes for Tanner crabs in glaciated ecosystems. High-catch areas for juvenile and adult female Tanner crabs were identified using local autocorrelation statistics. Spatial segregation by size class corresponded to features in the glacial landscape: high-catch areas for juveniles were located at the distal ends of two narrow glacial fjords, and high-catch areas for adults were located in the open waters of the central Bay. Juvenile female Tanner crabs were found at nearly all sampled depths (15–439 m) and temperatures (4–8°C), but the biggest catches were at depths <150 m where adults were scarce. Because adults may prey on or compete with juveniles, the distribution of juveniles could be influenced by the distribution of adults. Areas where adults or predators are scarce, such as glacially influenced fjords, could serve as refuges for juvenile Tanner crabs.

Ice-Ocean Interactions to the North-West of Greenland: Glaciers, Straits, Ice Bridges, and the Rossby Radius (Invited)

NASA Astrophysics Data System (ADS)

Muenchow, A.; Falkner, K. K.; Melling, H.; Johnson, H. L.; Huntley, H. S.; Ryan, P.; Friends Of Petermann

2010-12-01

Petermann Glacier at 81 N latitude is a major outlet glacier adjacent to Nares Strait. It terminates in a long (70 km), narrow (16 km) and thin (50 m) floating tongue and has a grounding line more than 500 m below sea level. A calving event in 2010 reduced the floating area by 25% and produced a single 240 km2 ice island currently moving south in Nares Strait where it will likely interact with island to potentially create a temporary polynya in Nares Strait. The 2010 calving from Petermann Glacier contributes <10% to its mass balance as more than 80% is lost due to basal melting by the ocean. Hence the largely unexplored physics at the ice-ocean interface determine how a changing climate impacts this outlet glacier. Conducting exploratory surveys inside Petermann Fjord in 2003, 2007, and 2009, we find a 1100 m deep fjord connected to Nares Strait via a sill at 350-450 m depth. The fjord receives about 3 times the amount of heat required for the basal melt rates. Furthermore, limited data and analytical modeling suggests a 3-dimensional circulation over the upper 300-m of the water column with a coastally trapped buoyant outflow. We integrate these findings with more complete oceanic time series data from an array moored in Nares Strait from 2003 through 2009 near 80.5 N. In the past Nares Strait and Petermann Fjord were covered by land fast sea ice during the 9-10 month long winter season. Archeological and remotely sensed records indicate that an ice bridge formed regularly at the southern end of Nares Strait creating the North-Water polynya near 79 N latitude. Since 2006 this ice bridge has largely failed to form, leading, perhaps, to the occasional formation of a secondary ice bridge 300 km to the north where Nares Strait connects to the Arctic Ocean. However, this ice bridge appears to form for shorter periods only. Consequently Arctic sea ice can now exit the Arctic in winter via pathways to the west of Greenland all year. We speculate that this changed ocean and sea ice regime in Nares Strait and the Arctic Ocean may contribute to the recently observed calving events in Petermann Fjord.

Effects of increase glacier discharge on phytoplankton bloom dynamics and pelagic geochemistry in a high Arctic fjord

NASA Astrophysics Data System (ADS)

Calleja, Maria Ll.; Kerhervé, P.; Bourgeois, S.; Kędra, M.; Leynaert, A.; Devred, E.; Babin, M.; Morata, N.

2017-12-01

Arctic fjords experience extremely pronounced seasonal variability and spatial heterogeneity associated with changes in ice cover, glacial retreat and the intrusion of continental shelf's adjacent water masses. Global warming intensifies natural environmental variability on these important systems, yet the regional and global effects of these processes are still poorly understood. In the present study, we examine seasonal and spatial variability in Kongsfjorden, on the western coast of Spitsbergen, Svalbard. We report hydrological, biological, and biogeochemical data collected during spring, summer, and fall 2012. Our results show a strong phytoplankton bloom with the highest chlorophyll a (Chla) levels ever reported in this area, peaking 15.5 μg/L during late May and completely dominated by large diatoms at the inner fjord, that may sustain both pelagic and benthic production under weakly stratified conditions at the glacier front. A progressively stronger stratification of the water column during summer and fall was shaped by the intrusion of warm Atlantic water (T > 3 °C and Sal > 34.65) into the fjord at around 100 m depth, and by turbid freshwater plumes (T < 1 °C and Sal < 34.65) at the surface due to glacier meltwater input. Biopolymeric carbon fractions and isotopic signatures of the particulate organic material (POM) revealed very fresh and labile material produced during the spring bloom (13C enriched, with values up to -22.7‰ at the highest Chl a peak, and high in carbohydrates and proteins content - up to 167 and 148 μg/L, respectively-), and a clear and strong continental signature of the POM present during late summer and fall (13C depleted, with values averaging -26.5‰, and high in lipid content - up to 92 μg/L-) when freshwater melting is accentuated. Our data evidence the importance of combining both physical (i.e. water mass dominance) and geochemical (i.e. characteristics of material released by glacier runoff) data in order to understand the timing, intensity and characteristics of the phytoplankton bloom in Kongsfjorden, a continuously changing system due to sustained warming. In a scenario where glacial retreat is predicted to increase the impacts of meltwater discharge and associated delivery of organic and inorganic material to the surrounding waters, special attention is required in order to predict the consequences for Arctic fjords and adjacent shelf ecosystems.

The history of retreat dynamics of Petermann Glacier inferred from submarine glacial landforms

NASA Astrophysics Data System (ADS)

Jakobsson, M.; Hogan, K.; Mayer, L. A.; Mix, A. C.; Jerram, K.; Mohammad, R.; Stranne, C.; Eriksson, B.

2016-12-01

Preserved submarine glacial landforms produced at the base and margin of ice sheets and outlet glaciers comprise records of past ice dynamics complementary to modern glaciological process studies. The Petermann 2015 Expedition on the Swedish icebreaker Oden systematically mapped approximately 3100 km2 of the seafloor in Petermann Fjord and the adjacent Hall Basin of Nares Strait, northwest Greenland, with an EM122 (12 kHz) multibeam and SBP120 (2-7 kHz) chirp sub-bottom profiler. Complete, overlapping mapping coverage permitted compilation of a high-quality (15x15m) digital terrain model (DTM). In addition, the seafloor at the margin of one of the smaller outlet glaciers draining into the Petermann Fjord and selected shallow areas along the coast were mapped using a small survey boat (RV Skidbladner), equipped with an EM2040 (200-300 kHz) multibeam. High-resolution (2 x 2 m) DTMs were compiled from the RV Skidbladner surveys. The seafloor morphology of Petermann Fjord and adjacent Hall Basin is dominated by a stunning glacial landform record comprising the imprints of Petermann Glacier's retreat dynamics since the Last Glacial Maximum (LGM). The entrance to Petermann Fjord consists of a prominent bathymetric sill formed by a large well-develop grounding zone wedge that undoubtedly represents a stability point during the glacier's retreat history. The deepest entrance to the fjord is 443 m and located on the southern side of this grounding zone wedge. Outside of this grounding zone wedge in Hall Basin, less well developed grounding zones appears to be present. The landform assemblage in between the grounding zones, in particular the lack of retreat ridges, may signify a leap-frog behavior of the glacier's retreat; rapid break-up and disintegration of the outlet glacier causing retreat back to the next stability point dictated by the local bedrock geology. While numerous classical glacial landforms characteristic for fast flowing ice streams are identified, the multibeam bathymetry also reveals an enigmatic, toilet bowl-shaped features whose origin is still unclear. The collected data during the Petermann 2015 Expedition will among other things provide new insights into ice shelf-ocean interactions, essential to projecting future climate impacts on Greenland and global sea level changes.

The impact of a hydroelectric power plant on the sediment load in downstream water bodies, Svartisen, northern Norway.

PubMed

Bogen, J; Bønsnes, T E

2001-02-05

When the Svartisen hydroelectric power plant was put into operation, extensive sediment pollution was observed in the downstream fjord area. This paper discusses the impact of the power plant and the contribution from various sources of sediment. Computation of the sediment load was based on samples collected one to four times per day. Grain size distribution analyses of suspended sediments were carried out and used as input in a routing model to study the movement of sediments through the system. Suspended sediment delivered to the fjord before the power station was constructed was measured as 8360 metric tons as an annual mean for a 12-year period. During the years 1995-1996 when the power plant was operating, the total suspended load through the power station was measured as 32609 and 30254 metric tons, respectively. Grain size distribution analyses indicate a major change in the composition of the sediments from 9% clay before the power plant was operative to 50-60% clay afterwards. This change, together with the increase in sediment load, is believed to be one of the main causes of the drastic reduction in secchi depths in the fjord. The effect of the suspended sediment load on the fjord water turbidity was evaluated by co-plotting secchi depth and power station water discharge. Measurements during 1995 and 1996 showed that at the innermost of these locations the water failed to attain the minimum requirement of 2 m secchi depth. In later years secchi depths were above the specified level. In 1997 and 1998 the conditions improved. At the more distal locality, the conditions were acceptable with only a few exceptions. A routing model was applied to data acquired at a location 2 km from the power station in order to calculate the contributions from various sediment sources. This model indicated that the contribution from reservoir bed erosion dominated in 1994 but decreased significantly in 1995. Future operation of the power station will mostly take place with a high water level in the reservoir and is likely to result in acceptable water quality in the fjord. However, during periods of low drawdown, sediment pollution may again become a problem.

What sediment plumes at tide water glaciers can tell us about fjord circulation and subglacial hydrology

NASA Astrophysics Data System (ADS)

Schild, K. M.; Hawley, R. L.

2013-12-01

Marine-terminating outlet glaciers discharge most of Greenland's mass, but the subglacial transport of meltwater is not well understood. The coincident rise in both ice velocity and surface melt during the last decade points to a possible link between the amount of surface melt, glacier velocities, and discharge rates through processes including basal lubrication and/or an increase in melt at the terminus due to discharge plume enhanced entrainment of warm ocean waters. Characterizing the response of the Greenland Ice Sheet to increasing melt is limited in part by the lack of direct observation of the subglacial system. We use ground-based observations (time lapse cameras, DMI weather stations) and satellite remote sensing (MODIS) to infer the subglacial hydrological evolution of a tidewater glacier by identifying the lag between meltwater availability, inferred from warm temperatures and supraglacial lake drainage, and the appearance of a sediment plume at the terminus. The detection of sediment plumes is constrained by melange presence in the spring and decreasing solar illumination in the fall. At Rink Isbræ, West Greenland, we find the appearance of sediment plumes lagging the onset of positive temperatures from 2007-2011 by approximately 44 days, but the plumes are present as the melange clears suggesting this lag may be much shorter but is undetectable. We also observe an abundance of sediment plumes each season (11-25 individual events), which indicates supraglacial drainage events are not the sole source for all sediment plumes. These findings suggest multiple passageways exist from the surface to the subglacial system and the presence of a well-established drainage network early in the melt season. In this poster, we will discuss potential mechanisms for the episodic nature of the recorded plume events; whether they are the product of variable subglacial water supply (suggesting the presence of pulse drainages from subglacial storage basins), highly variable fjord circulation (only allowing subglacial sediment plumes to appear at the surface under specific fjord and plume conditions), or a combination. A clearer understanding of sediment plumes are important for understanding the subglacial hydrological system of tidewater glaciers, as well as gauging the impact of rapid fresh water delivery to melange/sea ice extent in the fjord, terminus stability, submarine melting and fjord circulation.

Working With Greenlandic Fishermen: A New Approach to Citizen Science

NASA Astrophysics Data System (ADS)

Turrin, M.; Porter, D. F.; Greve, S.

2014-12-01

'Leveraging Local Knowledge to Measure Greenland Fjords' is a science project designed with local knowledge sharing and data collection at its core. Citizen Science can take many different forms but in each instance it incorporates active participation of the general public in science research through integrating outreach, instruction, information gathering and data exchange. The strongest projects focus on two-way information exchange with both the citizen scientist and the professional scientist learning when they share their knowledge. Working in cooperation with both teachers and fishermen in a small local community in northwest Greenland, we collected novel oceanographic measurements from a small 5 m fishing boat in the local fjord. We established connections with the local school for developing education initiatives, sharing maps and other resources, and worked through the teachers to connect with the village residents. We hosted a community meeting to provide a forum for a two-way information exchange with the science team providing background on the research project and the local residents providing both narrative information on local environmental change over the last one to three decades, and more quantitative and immediately useful information on fjord depths, iceberg flow directions and timing of seasonal ice break up and move out. The local fishermen were intimately familiar with the local environment, having intrinsically collected data on fjord depth from their regular lowering of fishing line to catch Greenlandic halibut, a benthic fish. For our first trip they worked with us locating the deep and shallow parts of the fjord from many seasons of watching icebergs ground on the shallow shoals, and showed us how to navigate into the ice packed glacial front through the dense ice mélange. The local community interest in the project and in learning how to use the equipment we had brought encouraged us to discuss a long-term data gathering relationship, with the fishermen at the center of the collection. They were interested in the findings, wanting to see how the water temperature might differ from surface to depth. The same data we are interested in for better understanding glacial change is data they seek to explain impacts they have seen in their own fishing and hunting over the last several decades.

Understanding changes in ice dynamics of southeast Greenland glaciers from high resolution gravimetry data and satellite remote sensing observations

NASA Astrophysics Data System (ADS)

Millan, R.; Rignot, E. J.; Mouginot, J.; Menemenlis, D.; Morlighem, M.; Wood, M.

2016-12-01

Southeast Greenland has been one of the largest contributors to ice mass losses in Greenland in the last few decades mostly as a result of changes in ice dynamics, and to a lesser extent due to the steady increase in runoff. In 1996, the region was thinning up to the ice divide (Krabill et al., 1999) and the change were clearly of ice dynamics nature. Ice-ocean interactions played a central role in triggering a faster, systematic retreat around year 2002-2005 as water of Atlantic origin started to intrude the fjords in larger amounts due to a change in oceanic circulation in the Irminger sea. The glacier response varied significantly from one glacier to the next in response to the oceanic change, which we attribute to variatioins in fjord bathymetry, geometry control on the glaciers and calving speed of the glaciers. This region is however characterized by a dearth of topography data: the fjords have never been mapped and bed topography is challenging to obtain with radio echo sounding techniques. Here, we employ a combination of Operation IceBridge (OIB) high-resolution airborne gravity from 2016, Ocean Melting Greenland (OMG) EVS-2 mission low resolution gravity from 2016, and OMG bathymetry data from 2016 to map the bed elevation of the glaciers and fjords over the entire southeast Greenland combining gravity, thickness, and bathymetry. The data reveal the true depth of the fjords and the glacier thickness at the ice front, in a seamless fashion. We combine these data with a history of ice discharge combining estimates of ice thickness with a time series of ice velocity going back to the early 1990s. We form a time series of ice discharge, glacier per glacier, which is compared with surface mass balance from the RACMO 1-km downscaled model. We compare the results with simulations of ice melt along the calving faces of the glaciers to draw conclusions about the sensitivity of each glacier to climate forcing and re-interpret their pattern of retreat in the last few decades. The simulation of ice melt employ the MITgcm ocean model constrained by water depth, thermal forcing from ECCO2 model and subglacial water fluxes from RACMO. This work was performed at UCI/JPL under a contract with NASA.

Age Estimates of Holocene Glacial Retreat in Lapeyrère Bay, Anvers Island, Antarctica

NASA Astrophysics Data System (ADS)

Mead, K. A.; Wellner, J. S.; Rosenheim, B. E.

2011-12-01

Lapeyrère Bay is a fjord on the eastern side of Anvers Island, located off the Western Antarctic Peninsula. Anvers island has a maximum elevation of 2400m (comprised of ice overlaying bedrock), and experiences colder temperatures and more precipitation than the South Shetlands, which are ~230km to the north. Two glaciers enter Lapeyrère Bay, one large and vulnerable to avalanching, the Iliad Glacier, and one smaller glacier confined to a northern unnamed cove. Though several research cruises have visited Lapeyrère Bay, very little has been published on the fjord's glacial retreat history or sediment flux. The primary purpose of this study is to reconstruct the glacial retreat and sediment flux histories of Lapeyrère Bay using a SHALDRIL core and standard piston cores for chronology and sedimentary facies analysis, and multibeam swath bathymetry data for identifying seafloor morphological features. Preliminary core data from the proximal northern flank of Lapeyrère Bay show greenish grey sandy mud with scattered pebble and sand lens lithology. A core taken in the distal-most part of the fjord is largely diatomaceous sediment grading into grey silty mud with thin sandy turbidites. Multibeam data has exposed seafloor features including a grounding zone wedge at the entrance of the unnamed cove of northern Lapeyrère Bay, drumlins, glacial lineations, and a glacial outwash fan near the ocean-termination of the Iliad glacier. Additionally, this study seeks to assess the effectiveness of a novel 14C method of dating sediment lacking sufficient calcareous material for carbonate 14C dating. The method being tested is ramped pyrolysis radiocarbon analysis, which dates individual fractions of organic material. It is hypothesized that ramped pyrolysis will improve upon bulk acid insoluble organic material (AIOM) dating, as AIOM can include both autochthonous syndepositionally aged carbon and allochthonous pre-aged carbon, resulting in 14C ages inherently older than the age of deposition. Performing ramped pyrolysis 14C dating and carbonate 14C dating on the same cores and comparing the resulting ages will address this hypothesis. Carbonate radiocarbon dating has been completed for cores taken in the proximal fjord, from the glacial outwash fan. Four dates from a 20.3m drill core yield an average sedimentation rate of 2.2mm/yr. Four dates from the nearby 293cm gravity core yield a sedimentation rate of 1.4mm/yr. Ramped pyrolysis has been performed on a total of nine samples, six taken from the proximal drill core and three taken from the distal-most gravity core of the fjord. The average proximal sample TOC is 0.22%, and the average distal sample TOC is 0.55%. These values show a trend of increasing TOC values with increasing oceanic influence in the distal fjord.

Circulation and sedimentation in a tidal-influenced fjord lake: Lake McKerrow, New Zealand

NASA Astrophysics Data System (ADS)

Pickrill, R. A.; Irwin, J.; Shakespeare, B. S.

1981-01-01

Lake McKerrow is a tide-influenced fjord lake, separated from the open sea by a Holocene barrier spit. Fresh, oxygenated waters of the epilimnion overlie saline, deoxygenated waters of the hypolimnion. During winter, water from the Upper Hollyford River interflows along the pycnocline, depositing coarse silt on the steep delta and transporting finer sediment down-lake. An extensive sub-lacustrine channel system on the foreset delta slope is possibly maintained by turbidity currents. Saline waters of the hypolimnion are periodically replenished. During high tides and low lake levels saline water flows into the lake and downslope into the lake basin as a density current in a well defined channel.

Pathways of Petermann Glacier meltwater, Greenland

NASA Astrophysics Data System (ADS)

Heuzé, Céline; Wåhlin, Anna; Johnson, Helen; Münchow, Andreas

2016-04-01

Radar and satellite observations suggest that the floating ice shelf of Petermann Glacier loses up to 80% of its mass through basal melting, caused by the intrusion of warm Atlantic Water into the fjord and under the ice shelf. The fate of Petermann's glacial meltwater is still largely unknown. It is investigated here, using hydrographic observations collected during a research cruise on board I/B Oden in August 2015. Two methods are used to detect the meltwater from Petermann: a mathematical one that provides the concentration of ice shelf meltwater, and a geometrical one to distinguish the meltwater from Petermann and the meltwater from other ice shelves. The meltwater from Petermann mostly circulates on the north side of the fjord. At the sill, 0.5 mSv of meltwater leave the fjord, mostly on the northeastern side between 100 and 350 m depth, but also in the central channel, albeit with a lesser concentration. Meltwater from Petermann is found in all the casts in Hall Basin, notably north of the sill by Greenland coast. The geometrical method reveals that the casts closest to the Canadian side mostly contain meltwater from other, unidentified glaciers. As Atlantic Water warms up, it is key to monitor Greenland melting glaciers and track their meltwater to properly assess their impact on the ocean circulation and sea level rise.

IceBridge Survey Flight Over Saunders Island and Wolstenholme Fjord

NASA Image and Video Library

2017-12-08

This image of Saunders Island and Wolstenholme Fjord with Kap Atholl in the background was taken during an Operation IceBridge survey flight in April, 2013. Sea ice coverage in the fjord ranges from thicker, white ice seen in the background, to thinner grease ice and leads showing open ocean water in the foreground. In March 2013, NASA's Operation IceBridge scientists began another season of research activity over Arctic ice sheets and sea ice. IceBridge, a six-year NASA mission, is the largest airborne survey of Earth's polar ice ever flown. It will yield an unprecedented three-dimensional view of Arctic and Antarctic ice sheets, ice shelves and sea ice. These flights will provide a yearly, multi-instrument look at the behavior of the rapidly changing features of the Greenland and Antarctic ice. Image Credit: NASA / Michael Studinger Read more about the mission here: www.nasa.gov/mission_pages/icebridge/index.html NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Status and distribution of the Kittlitz's murrelet Brachyramphus brevirostris in Kenai Fjords, Alaska

USGS Publications Warehouse

Arimitsu, Mayumi L.; Piatt, John F.; Romano, Marc D.; van Pelt, Thomas I.

2011-01-01

The Kittlitz's Murrelet Brachyramphus brevirostris is a candidate species for listing under the US Endangered Species Act because of its apparent declines within core population areas of coastal Alaska. During the summers of 2006-2008, we conducted surveys in marine waters adjacent to Kenai Fjords National Park, Alaska, to estimate the current population size of Kittlitz's and Marbled murrelets B. marmoratus and examine seasonal variability in distribution within coastal fjords. We also evaluated historical data to estimate trend. Based on an average of point estimates, we find the recent population (95% CI) of Kittlitz's Murrelet to be 716 (353-1080) individuals, that of Marbled Murrelet to be 6690 (5427-7953) individuals, and all Brachyramphus murrelets combined to number 8186 (6978-9393) birds. Within-season density estimates showed Kittlitz's Murrelets generally increased between June and July, but dispersed rapidly by August, while Marbled Murrelets generally increased throughout the summer. Trends in Kittlitz's and Marbled murrelet populations were difficult to assess with confidence. Methods for counting or sampling murrelets varied in early decades of study, while in later years there is uncertainty due to highly variable counts among years, which may be due in part to timing of surveys relative to the spring bloom in coastal waters of the Gulf of Alaska.

New constraints on the deglaciation chronology of the southeastern margin of the Greenland Ice Sheet

NASA Astrophysics Data System (ADS)

Levy, L.; Larsen, N. K.; Kjaer, K. H.; Bjork, A. A.; Kjeldsen, K. K.; Funder, S.; Kelly, M. A.; Howley, J. A.; Zimmerman, S. R. H.

2015-12-01

The Greenland Ice Sheet (GrIS) is responding rapidly to climate change. Marine terminating outlet glaciers that drain the GrIS have responded especially sensitively to present-day climate change by accelerating, thinning and retreating. In southeastern Greenland several outlet glaciers are undergoing rapid changes in mass balance and ice dynamics. To improve our understanding of the future, long-term response of these marine-terminating outlet glaciers to climate change, we focus on the response of three outlet glaciers to climate change since the Last Glacial Maximum. The timing and rates of late-glacial and early Holocene deglaciation of the southeastern sector of the GrIS are relatively unconstrained due to the inaccessibility of the region. Using a helicopter and a sailboat, we collected samples for 10Be surface exposure dating from three fjords in southeastern Greenland: Skjoldungen (63.4N), Uvtorsiutit (62.7N), and Lindenow (60.6N). These fjords drain marine terminating glaciers of the GrIS. Here we present 18 new 10Be ages from ~50 km long transects along these fjords that mark the timing of deglaciation from the outer coast inland to the present-day GrIS margin. Together with previously constrained deglaciation chronologies from Bernstorffs, Sermilik, and Kangerdlussuaq fjords in southeastern Greenland, these new chronologies offer insight into the late-glacial and early Holocene dynamics of the southeastern GrIS outlet glaciers. We compare the timing and rate of deglaciation in southeastern Greenland to climate records from the region to examine the mechanisms that drove deglaciation during late-glacial and early Holocene time. These new 10Be ages provide a longer-term perspective of marine terminating outlet glacier fluctuations in southeastern Greenland and can be used to model the ice sheet's response to late-glacial and early Holocene climate changes.

Oceanography of Glacier Bay, Alaska: Implications for biological patterns in a glacial fjord estuary

USGS Publications Warehouse

Etherington, L.L.; Hooge, P.N.; Hooge, Elizabeth Ross; Hill, D.F.

2007-01-01

Alaska, U.S.A, is one of the few remaining locations in the world that has fjords that contain temperate idewater glaciers. Studying such estuarine systems provides vital information on how deglaciation affects oceanographic onditions of fjords and surrounding coastal waters. The oceanographic system of Glacier Bay, Alaska, is of particular interest ue to the rapid deglaciation of the Bay and the resulting changes in the estuarine environment, the relatively high oncentrations of marine mammals, seabirds, fishes, and invertebrates, and the Bay’s status as a national park, where ommercial fisheries are being phased out. We describe the first comprehensive broad-scale analysis of physical and iological oceanographic conditions within Glacier Bay based on CTD measurements at 24 stations from 1993 to 2002. easonal patterns of near-surface salinity, temperature, stratification, turbidity, and euphotic depth suggest that freshwater nput was highest in summer, emphasizing the critical role of glacier and snowmelt to this system. Strong and persistent tratification of surface waters driven by freshwater input occurred from spring through fall. After accounting for seasonal nd spatial variation, several of the external physical factors (i.e., air temperature, precipitation, day length) explained a large mount of variation in the physical properties of the surface waters. Spatial patterns of phytoplankton biomass varied hroughout the year and were related to stratification levels, euphotic depth, and day length. We observed hydrographic atterns indicative of strong competing forces influencing water column stability within Glacier Bay: high levels of freshwater ischarge promoted stratification in the upper fjord, while strong tidal currents over the Bay’s shallow entrance sill enhanced ertical mixing. Where these two processes met in the central deep basins there were optimal conditions of intermediate tratification, higher light levels, and potential nutrient renewal. These conditions were associated with high and sustained hlorophylla levels observed from spring through fall in these zones of the Bay and provide a framework for understanding he abundance patterns of higher trophic levels within this estuarine system.

Holocene Mass Transport Deposits in Western Norwegian fjords and lakes revealing prehistoric earthquake history of Scandinavia

NASA Astrophysics Data System (ADS)

Bellwald, B.; Hjelstuen, B. O.; Sejrup, H. P.; Kuvås, J.; Stokowy, T.

2016-12-01

The sensitivity of fjord sediments to seismic shaking makes fjord systems appropriate study sites when extending regional earthquake catalogs back in time and when estimating recurrence rates of prehistoric earthquakes in intraplate settings. In this study we compiled evidence of 140 postglacial mass movement events and their associated mass transport deposits (MTDs) from previously analyzed and new sediment cores and high-resolution seismic profiles from 22 fjord systems and six lakes in Western Norway. Evaluation of trigger mechanisms make us infer that most of these mass movement events were initiated by regional earthquakes, and that both climate-related processes and tsunamis most likely can be excluded as trigger mechanism for most of the events. A total of 33 individual earthquakes has been identified, which most likely outbalance the historically recorded events in magnitude, thus indicating magnitudes >6. Frequency plots of MTDs suggest high seismic activity in the early Holocene (11000-9700 cal. yrs BP), followed by seismic quiescence in the mid-Holocene before a seismic reactivation took place at 4000 cal. yrs BP. Coevally-triggered MTDs at 8100 cal. yrs BP are identified in all the archives, and are correlating with the age of the offshore Storegga slide. We estimate earthquake recurrence rates of 1/80 years directly after the last deglaciation of Western Norway (12800-11600 ca. yrs BP), 1/200 years for the early Holocene and 1/300 years for the last 4000 years. Our compilation suggests that the mid-Holocene is characterized by low seismic activity, suggesting recurrence rates of 1/1300 years. Comparisons of the Western Norwegian dataset with paleoseimologic studies of other previously glaciated intraplate settings indicate that both Scandinavia and the Alps show similar trends as Western Norway, whereas Eastern Canada is not correlating with the paleoseismologic trend of this study, which could be explained by different deglaciation histories.

Marine biodiversity at the end of the world: Cape Horn and Diego Ramírez islands.

PubMed

Friedlander, Alan M; Ballesteros, Enric; Bell, Tom W; Giddens, Jonatha; Henning, Brad; Hüne, Mathias; Muñoz, Alex; Salinas-de-León, Pelayo; Sala, Enric

2018-01-01

The vast and complex coast of the Magellan Region of extreme southern Chile possesses a diversity of habitats including fjords, deep channels, and extensive kelp forests, with a unique mix of temperate and sub-Antarctic species. The Cape Horn and Diego Ramírez archipelagos are the most southerly locations in the Americas, with the southernmost kelp forests, and some of the least explored places on earth. The giant kelp Macrocystis pyrifera plays a key role in structuring the ecological communities of the entire region, with the large brown seaweed Lessonia spp. forming dense understories. Kelp densities were highest around Cape Horn, followed by Diego Ramírez, and lowest within the fjord region of Francisco Coloane Marine Park (mean canopy densities of 2.51 kg m-2, 2.29 kg m-2, and 2.14 kg m-2, respectively). There were clear differences in marine communities among these sub-regions, with the lowest diversity in the fjords. We observed 18 species of nearshore fishes, with average species richness nearly 50% higher at Diego Ramírez compared with Cape Horn and Francisco Coloane. The number of individual fishes was nearly 10 times higher at Diego Ramírez and 4 times higher at Cape Horn compared with the fjords. Dropcam surveys of mesophotic depths (53-105 m) identified 30 taxa from 25 families, 15 classes, and 7 phyla. While much of these deeper habitats consisted of soft sediment and cobble, in rocky habitats, echinoderms, mollusks, bryozoans, and sponges were common. The southern hagfish (Myxine australis) was the most frequently encountered of the deep-sea fishes (50% of deployments), and while the Fueguian sprat (Sprattus fuegensis) was the most abundant fish species, its distribution was patchy. The Cape Horn and Diego Ramírez archipelagos represent some of the last intact sub-Antarctic ecosystems remaining and a recently declared large protected area will help ensure the health of this unique region.

Glacimarine sedimentary processes, facies and morphology of the south-southeast Alaska shelf and fjords

USGS Publications Warehouse

Powell, R.D.; Molnia, B.F.

1989-01-01

High precipitation from Gulf of Alaska air masses can locally reach up to 800 cm a-1. This precipitation on tectonically active mountains creates cool-temperate glaciation with extremely active erosion and continuously renewed resources. High basal debris loads up to 1.5 m thick of pure debris and rapid glacial flow, which can be more than 3000 m a-1, combine to produce large volumes of siliciclastic glacimarine sediment at some of the highest sediment accumulation rates on record. At tidewater fronts of valley glaciers, sediment accumulation rates can be over 13 m a-1 and deltas commonly grow at about 106 m3 a-1. Major processes influencing glacimarine sedimentation are glacial transport and glacier-contact deposition, meltwater (subaerial and submarine) and runoff transport and deposition, iceberg rafting and gouging, sea-ice transport, wave action and storm reworking, tidal transport and deposition, alongshelf transport, sliding and slumping and gravity flows, eolian transport, and biogenic production and reworking. Processes are similar in both shelf and fjord settings; however, different intensities of some processes create different facies associations and geometries. The tectonoclimatic regime also controls morphology because bedrock structure is modified by glacial action. Major glacimarine depositional systems are all siliciclastic. They are subglacial, marginal-morainal bank and submarine outwash, and proglacial/paraglacial-fluvial/deltaic, beach, tidal flat/estuary, glacial fjord, marine outwash fjord and continental shelf. Future research should include study of long cores with extensive dating and more seismic surveys to evaluate areal and temporal extent of glacial facies and glaciation; time-series oceanographic data, sidescan sonar surveys and submersible dives to evaluate modern processes; biogenic diversity and production to evaluate paleoecological, paleobiogeographic and biofacies analysis; and detailed comparisons of exposed older rock of the Yakataga Formation to evaluate how glacial style has evolved over 6.3 Ma. ?? 1989.

The turbulent life of juvenile icebergs: Observations from an array of high-rate time-lapse cameras in LeConte Bay, Alaska

NASA Astrophysics Data System (ADS)

Kienholz, C.; Amundson, J. M.; Jackson, R. H.; Motyka, R. J.; Nash, J. D.; Sutherland, D.

2017-12-01

Tidewater glacier behavior is driven by poorly understood processes occurring at the ice-ocean interface, including sedimentation and erosion, iceberg calving, and submarine melting. These processes are inherently difficult to observe, calling for innovative field techniques and numerical models. As part of a multi-year field effort to constrain ocean-glacier heat and mass exchange, we deployed an array of high-rate time-lapse cameras (sampling intervals between 15 seconds and 2 minutes) to monitor the terminus of LeConte Glacier and its proglacial fjord. The camera array has operated continuously for more than a year. Our high sampling rates enable tracking of iceberg motion with optical flow algorithms, which have been used widely in computer vision but less so in glaciology and oceanography. Such algorithms track individual features (e.g., corners of icebergs), which is ideal for iceberg-rich fjords, where motion can vary substantially over short temporal and spatial scales (e.g., due to complex surface currents or different iceberg sizes). We process our data to quantify subdaily to seasonal patterns in surface currents and relate them to forcing from tides, wind, and glacier runoff. Flow is most variable close to the glacier terminus due to frequent calving events and turbulent plume dynamics. Farther down fjord, more consistent patterns emerge, driven by tides, wind, and runoff and altered by fjord geometry. Our tracking results compare favorably to and complement our Acoustic Doppler Current Profiler measurements from boats and moorings. Given their high spatial and temporal resolution, our observations will place important surface constraints on forthcoming hydrodynamic modeling efforts. The deployment of the cameras in a harsh environment and the corresponding image processing provided an opportunity to test hardware and software thoroughly, which will prove useful for similar systems at other glaciers.

Marine biodiversity at the end of the world: Cape Horn and Diego Ramírez islands

PubMed Central

Ballesteros, Enric; Bell, Tom W.; Giddens, Jonatha; Henning, Brad; Hüne, Mathias; Muñoz, Alex; Salinas-de-León, Pelayo; Sala, Enric

2018-01-01

The vast and complex coast of the Magellan Region of extreme southern Chile possesses a diversity of habitats including fjords, deep channels, and extensive kelp forests, with a unique mix of temperate and sub-Antarctic species. The Cape Horn and Diego Ramírez archipelagos are the most southerly locations in the Americas, with the southernmost kelp forests, and some of the least explored places on earth. The giant kelp Macrocystis pyrifera plays a key role in structuring the ecological communities of the entire region, with the large brown seaweed Lessonia spp. forming dense understories. Kelp densities were highest around Cape Horn, followed by Diego Ramírez, and lowest within the fjord region of Francisco Coloane Marine Park (mean canopy densities of 2.51 kg m-2, 2.29 kg m-2, and 2.14 kg m-2, respectively). There were clear differences in marine communities among these sub-regions, with the lowest diversity in the fjords. We observed 18 species of nearshore fishes, with average species richness nearly 50% higher at Diego Ramírez compared with Cape Horn and Francisco Coloane. The number of individual fishes was nearly 10 times higher at Diego Ramírez and 4 times higher at Cape Horn compared with the fjords. Dropcam surveys of mesophotic depths (53–105 m) identified 30 taxa from 25 families, 15 classes, and 7 phyla. While much of these deeper habitats consisted of soft sediment and cobble, in rocky habitats, echinoderms, mollusks, bryozoans, and sponges were common. The southern hagfish (Myxine australis) was the most frequently encountered of the deep-sea fishes (50% of deployments), and while the Fueguian sprat (Sprattus fuegensis) was the most abundant fish species, its distribution was patchy. The Cape Horn and Diego Ramírez archipelagos represent some of the last intact sub-Antarctic ecosystems remaining and a recently declared large protected area will help ensure the health of this unique region. PMID:29364902

Organic carbon in glacial fjords of Chilean Patagonia

NASA Astrophysics Data System (ADS)

Pantoja, Silvio; Gutiérrez, Marcelo; Tapia, Fabián; Abarzúa, Leslie; Daneri, Giovanni; Reid, Brian; Díez, Beatriz

2016-04-01

The Southern Ice Field in Chilean Patagonia is the largest (13,000 km2) temperate ice mass in the Southern hemisphere, yearly transporting ca. 40 km3 of freshwater to fjords. This volume of fresh and cold water likely affects adjacent marine ecosystems by changing circulation, productivity, food web dynamics, and the abundance and distribution of planktonic and benthic organisms. We hypothesize that freshwater-driven availability of inorganic nutrient and transport of organic and inorganic suspended matter, as well as microbes, become a controlling factor for productivity in the fjord associated with the Baker river and Jorge Montt glacier. Both appear to be sources of silicic acid, but not of nitrate and particulate organic carbon, especially during summer, when surface PAR and glacier thawing are maximal. In contrast to Baker River, the Jorge Montt glacier is also a source of dissolved organic carbon towards a proglacial fjord and the Baker Channel, indicating that a thorough chemical description of sources (tidewater glacier and glacial river) is needed. Nitrate in fiord waters reaches ca. 15 μM at 25 m depth with no evidence of mixing up during summer. Stable isotope composition of particulate organic nitrogen reaches values as low as 3 per mil in low-salinity waters near both glacier and river. Nitrogen fixation could be depleting δ15N in organic matter, as suggested by the detection at surface waters of nif H genes belonging to diazotrophs near the Montt glacier. As diazotrophs have also been detected in other cold marine waters (e.g. Baltic Sea, Arctic Ocean) as well as glaciers and polar terrestrial waters, there is certainly a potential for both marine and freshwater microbes to contribute and have a significant impact on the Patagonian N and C budgets. Assessing the impact of freshwater on C and N fluxes and the microbial community structure in Patagonian waters will allow understanding future scenarios of rapid glacier melting. This research was funded by COPAS Sur-Austral (PFB-31).

Three-dimensional simulation of a rock slide impact into water

NASA Astrophysics Data System (ADS)

Weaver, R.; Gisler, G.; Gittings, M.; Ranta, D.

2007-12-01

The steep-sided fjords of western Norway have experienced numerous rock slide events that sometimes produced devastating tsunamis. The 1934 slide in the Tafjord region, when some 3 million cubic meters of rock plunged into the water, resulted in waves tens of meters high that destroyed two villages and killed about 40 people. A similarly dangerous situation exists now in Sunnylvsfjord, where a major expanding crack in the fjord wall at Aknes threatens to release from 5 to 40 million cubic meters of rock into the water. Such an event would devastate a large region, including the Geiranger Fjord, a UN World Heritage Site that is extremely popular with tourists. The Norwegian Government's Aknes-Tafjord project is responsible for studying and monitoring the potential slide area and for providing adequate warning to protect lives and property. In order to better understand tsunami generation from such events, we have performed 3-dimensional fully compressible hydrodynamical simulations of the impact of a large number of boulders from a steep slope into a deep body of water. We use the Los Alamos/SAIC adaptive-mesh-refined SAGE code, previously used to model tsunamis from underwater explosions, asteroid impacts, and both subaqueous and subaerial landslide sources. We find the interaction of boulders and water to be extremely turbulent and dissipative. It differs markedly from simulations of large-block impacts in similar geometry. No more than about 15% of the potential energy of the boulders ends up in the water wave. The rest of the energy goes into heating the boulders (and presumably fragmenting them, though that physics is not included) into generating winds, heating air and water, and generating turbulence. In the near field, the waves produced by the impact can be quite high -- tens of meters -- and have the potential to devastate coastlines at substantial distances from the site along a narrow fjord system.

Corrigendum to ``Seasonality of vertical flux and sinking particle characteristics in an ice-free high arctic fjord - Different from subarctic fjords?'' [J. Mar. Syst. 154 (2016) 192-205

NASA Astrophysics Data System (ADS)

Wiedmann, Ingrid; Reigstad, Marit; Marquardt, Miriam; Vader, Anna; Gabrielsen, Tove M.

2018-02-01

In our original publication the particle volume flux was by mistake standardized to area A = sediment trap diameter2 ∗ pi instead of A = sediment trap radius2 ∗ pi (A being the opening of the sediment trap). In addition, the particle flux data from Spring II (30 m and 60 m) and Spring III (20 m) were standardized twice to deployment time, instead of to the deployment time and the sediment trap opening. These mistakes do not affect our conclusions, but we would like to present here the correct numbers for the result section 3.4, discussion section 4.3 and a revised Fig. 5.

Molecular characterization of sulfate-reducing bacteria in the Guaymas Basin

NASA Technical Reports Server (NTRS)

Dhillon, Ashita; Teske, Andreas; Dillon, Jesse; Stahl, David A.; Sogin, Mitchell L.

2003-01-01

The Guaymas Basin (Gulf of California) is a hydrothermal vent site where thermal alteration of deposited planktonic and terrestrial organic matter forms petroliferous material which supports diverse sulfate-reducing bacteria. We explored the phylogenetic and functional diversity of the sulfate-reducing bacteria by characterizing PCR-amplified dissimilatory sulfite reductase (dsrAB) and 16S rRNA genes from the upper 4 cm of the Guaymas sediment. The dsrAB sequences revealed that there was a major clade closely related to the acetate-oxidizing delta-proteobacterial genus Desulfobacter and a clade of novel, deeply branching dsr sequences related to environmental dsr sequences from marine sediments in Aarhus Bay and Kysing Fjord (Denmark). Other dsr clones were affiliated with gram-positive thermophilic sulfate reducers (genus Desulfotomaculum) and the delta-proteobacterial species Desulforhabdus amnigena and Thermodesulforhabdus norvegica. Phylogenetic analysis of 16S rRNAs from the same environmental samples resulted in identification of four clones affiliated with Desulfobacterium niacini, a member of the acetate-oxidizing, nutritionally versatile genus Desulfobacterium, and one clone related to Desulfobacula toluolica and Desulfotignum balticum. Other bacterial 16S rRNA bacterial phylotypes were represented by non-sulfate reducers and uncultured lineages with unknown physiology, like OP9, OP8, as well as a group with no clear affiliation. In summary, analyses of both 16S rRNA and dsrAB clone libraries resulted in identification of members of the Desulfobacteriales in the Guaymas sediments. In addition, the dsrAB sequencing approach revealed a novel group of sulfate-reducing prokaryotes that could not be identified by 16S rRNA sequencing.

Atlantic water variability on the SE Greenland continental shelf and its relationship to SST

NASA Astrophysics Data System (ADS)

Sutherland, D. A.; Straneo, F.; Rosing-Asvid, A.; Stenson, G.; Davidson, F. J.; Hammill, M.

2012-12-01

Interaction of warm, Atlantic-origin water (AW) and colder, polar origin water (PW) advecting southward in the East Greenland Current (EGC) influences the heat content of water entering Greenland's outlet glacial fjords. Here we use depth and temperature data derived from deep-diving seals to map out water mass variability across the continental shelf and to augment existing bathymetric products. We find two dominant modes in the vertical temperature structure: a cold mode, with the typical AW/PW layering observed in the EGC, and a warm mode, where AW is present throughout the water column. The prevalence of these modes varies seasonally and spatially across the continental shelf, implying distinct AW pathways. In addition, we find that satellite sea surface temperatures (SST) correlate significantly with temperatures in the upper 50 m (R=0.54), but this correlation decreases with depth (R=0.22 at 200 m), and becomes insignificant below 250 m. Thus, care must be taken in using SST as a proxy for heat content, as AW mainly resides in these deeper layers. Regional map showing the location of all seal tracks originating from Canada and Greenland (stars). Tracks passing inside (red) or outside (blue) the SE Greenland region (black) were subdivided into continental shelf regions (green boxes) near Sermilik Fjord (SF), Cape Farewell (CF) and Kangerdlugssuaq Fjord (KG). GEBCO bathymetry is contoured at 200, 1000, 2000, and 3000 m.

Summer inventory of landbirds in Kenai Fjords National Park

USGS Publications Warehouse

2006-01-01

As part of the National Park Service Inventory and Monitoring Program, we conducted a summer inventory of landbirds within Kenai Fjords National Park. Using a stratified random sampling design of areas accessible by boat or on foot, we selected sites that encompassed the breadth of habitat types within the Park. We detected 101 species across 52 transects, including 62 species of landbirds, which confirmed presence of 87% of landbird species expected to occur in the Park during the summer breeding season. We found evidence of breeding for three Partners in Flight Watch List species, Rufous Hummingbird (Selasphorus rufus), Olive-sided Flycatcher (Contopus cooperi), and Rusty Blackbird (Euphagus carolinus), which are of particular conservation concern due to recent population declines. Kenai Fjords National Park supports extremely high densities of Hermit Thrush, Orange-crowned Warbler, and Wilson’s Warbler (Wilsonia pusilla) compared with other regions of Alaska. Other commonly observed species included Fox Sparrow (Passerella iliaca), Varied Thrush (Ixoreus naevius), Rubycrowned Kinglet (Regulus calendula), and Yellow Warbler (Dendroica petechia). More than half of the landbird species we observed occurred in needleleaf forests, and several of these species were strongly associated with the coastforest interface. Tall shrub habitats, which occurred across all elevations and in recently deglaciated areas, supported high densities and a diverse array of passerines. Two major riparian corridors, with their broadleaf forests, wetlands, and connectivity to interior Alaska, provided unique and important landbird habitats within the region.

Studying onshore-offshore fault linkages and landslides in Icy Bay and Taan Fjord to assess geohazards in Southeast Alaska

NASA Astrophysics Data System (ADS)

McCall, N.; Walton, M. A. L.; Gulick, S. P. S.; Haeussler, P. J.; Reece, R.; Saustrup, S.

2016-12-01

In southeast Alaska, the plate boundary where the Yakutat microplate collides with North America has produced large historical earthquakes (i.e., the Mw 8+ 1899 sequence). Despite the seismic potential, the possible source fault systems for these earthquakes have not been imaged with modern methods in Icy Bay. The offshore Pamplona Zone and its eastward onshore extension, the Malaspina Fault, may have played a role in the September 1899 earthquakes. Onshore and offshore mapping indicates that these structures likely connect offshore in Icy Bay. In August 2016 we collected high-resolution (300-1200 Hz) seismic reflection and multibeam bathymetry data to search for evidence of such faults beneath Icy Bay and Taan Fiord. If the Malaspina Fault is found to link with the Pamplona Zone, a rupture could trigger a tsunami impacting the populated regions in southeast Alaska. More recently, on October 17th 2015, nearby Taan Fjord experienced one of the largest non-volcanic landslides recorded in North America. Approximately 200 million metric tons spilled into Taan Fjord creating a tsunami with waves reaching 150m onshore. Using the new data, we are capable of imaging landslide and tsunami deposits in high-resolution. These data give new constraints for onshore-offshore fault systems, giving us new insights into the earthquake and tsunami hazard in southeast Alaska.

Carbon Processing in Aquatic Critical Zones: A Source-to-Sink Perspective

NASA Astrophysics Data System (ADS)

Bianchi, T. S.

2017-12-01

The majority of organic carbon (OC) in the global ocean is buried in the coastal margin. In particular, river delta and non-deltaic shelf regions bury an estimated 114 Tg C year-1 and 70 Tg C year-1, respectively, with only ca. 6 Tg C year-1 buried in the open ocean. While there has long standing general agreement that continental selves represent the largest sink of both terrestrial (OCterr) and marine (OCmari) OC in the global ocean, our understanding of the spatial and temporal complexity of this region continues to evolve. For example, fjords are now more recognized as "hotspots"of carbon burial with recent estimates suggesting fjord surface area-normalized OC burial rates are at least five times greater than other marine systems and one hundred times greater than the entire ocean average. Here, I will compare and contrast some of the key molecular biomarkers that have been used to date to track OC across different depositional environments (e.g., large river deltas and fjords) and explore how margin-type, residence time of transport, reservoir dams, redox, priming effects, and molecular stability, impact the utility of using different biomarkers in coastal OC cycling. Finally, I will focus on important critical zones within the aquatic continuum from land-to-sea and examine how more attention is needed better understand OC cycling in these new dynamic interfaces in the Anthropocene.

Norwegian fjord sediments reveal NAO related winter temperature and precipitation changes of the past 2800 years

NASA Astrophysics Data System (ADS)

Faust, Johan C.; Fabian, Karl; Milzer, Gesa; Giraudeau, Jacques; Knies, Jochen

2016-02-01

The North Atlantic Oscillation (NAO) is the leading mode of atmospheric circulation variability in the North Atlantic region. Associated shifts of storm tracks, precipitation and temperature patterns affect energy supply and demand, fisheries and agricultural, as well as marine and terrestrial ecological dynamics. Long-term NAO records are crucial to better understand its response to climate forcing factors, and assess predictability and shifts associated with ongoing climate change. A recent study of instrumental time series revealed NAO as main factor for a strong relation between winter temperature, precipitation and river discharge in central Norway over the past 50 years. Here we compare geochemical measurements with instrumental data and show that primary productivity recorded in central Norwegian fjord sediments is sensitive to NAO variability. This observation is used to calibrate paleoproductivity changes to a 500-year reconstruction of winter NAO (Luterbacher et al., 2001). Conditioned on a stationary relation between our climate proxy and the NAO we establish a first high resolution NAO proxy record (NAOTFJ) from marine sediments covering the past 2800 years. The NAOTFJ shows distinct co-variability with climate changes over Greenland, solar activity and Northern Hemisphere glacier dynamics as well as climatically associated paleo-demographic trends. The here presented climate record shows that fjord sediments provide crucial information for an improved understanding of the linkages between atmospheric circulation, solar and oceanic forcing factors.

Back-analysis of the 1756 Tjellefonna rockslide (western Norway)

NASA Astrophysics Data System (ADS)

Sandøy, Gro; Oppikofer, Thierry; Nilsen, Bjørn

2014-05-01

The 22nd of February 1756 the largest historically recorded rockslide in Norway took place at Tjelle in Lang Fjord (western Norway). Three displacement waves of up to 50 meters were created by the impact of the failed rock mass constituting the Tjellefonna rockslide. A total of 32 people were killed and several houses and boats around the fjord were destroyed. This study presents a back-analysis of the Tjellefonna rockslide by (1) reconstructing the topography before the rockslide, (2) assessing the volumes of the initial rockslide mass, the onshore deposits and offshore deposits, (3) assessing the major discontinuities involved in the rockslide, and (4) by 2D numerical slope stability modelling for a detailed study of the parameters and trigger factors that affected the slope stability. The topography before the rockslide is reconstructed using (1) the Sloping Local Base Level technique and (2) a manual ART reconstruction in the PolyWorks software. Both topographic reconstructions yield an initial rockslide volume between 9.2 and 10.4 million m3, which is lower than previous estimates (12-15 million m3). The onshore deposits are estimated to 7.6 million m3 and only 3.9 million m3 deposited in the fjord. Finally, the volume impacting the fjord (3.9 million m3) is important for the generation of rockslide-triggered displacement waves, which highlights the necessity of precise volume estimations prior to back-analyses of landslide-triggered displacement waves. The granitic to granodioritic gneissic rock mass at Tjellefonna have high to very high mechanical strength. However, field mapping reveals that the intact rock strength is compromised by a combination of a variably developed foliation, extensive faulting and four persistent joint sets. The foliation is often folded into open folds with sub-horizontal axial planes. The foliation, faults and two joint sets are sub-parallel to Langfjorden and to regional structural lineaments. The back walls of the Tjellefonna crown are made up of a combination of these structures, while two joint sets that strike perpendicular to the fjord define the flanks of the scar. The numerical slope stability model Phase2 analyses include shear strength reduction (SSR) investigations and parameter sensitive tests. These tests demonstrate that the failure of the Tjellefonna slope must have required strain softening in combination with triggering factors, where high groundwater level is an essential feature. An earthquake has previously been assumed as trigger, but sensitivity tests rule out seismic acceleration as a factor alone. Additionally, the analyses show that a sub-horizontal discontinuity set is critical in order to induce slope instability. The shallow fjord-dipping joint set and sub-horizontal fault might form this necessary discontinuity, although they were only mapped locally and their persistence was limited. The sliding surface has been evaluated using the Phase2 model and the topographic reconstructions. It is concluded that the Tjellefonna rockslide was not composed of a uniform plane, but of a complex surface consisting of joints, faults, foliation surfaces and intact rock bridges. Finally, the failure was thus likely a consequence of progressive accumulation of rock weakening (strain softening), acting to degrade the equilibrium state of the slope. This could have generated a hillside creep explaining the opening tension cracks observed at the present head scarp prior to the rockslide.

Air temperature and humidity diversity in the Hornsund fjord area (Spitsbergen) in the period 1 July 2014 - 30 June 2015

NASA Astrophysics Data System (ADS)

Przybylak, Rajmund; Araźny, Andrzej; Wyszyński, Przemysław; Budzik, Tomasz; Wawrzyniak, Tomasz

2016-04-01

The article presents preliminary results of studies into the spatial diversity of air temperature and relative humidity (overground layer, 2 m a.g.l.) in the area of the Hornsund fjord (S Spitsbergen, approx. 77°N), based on data collected between 1 July 2014 and 30 June 2015. The Hornsund fjord runs latitudinal along approx. 40 km and its average width is about 10 km. Numerous glaciers flow into the fjord and the mountain ridges around it often exceed 700 m a.s.l. Data series obtained from 11 sites equipped with automatic weather stations (Vaisala, Campbell, Davis) or HOBO temperature and humidity sensors were used. Two sites (Hornsund HOR and the Hans Glacier HG4) have been operating for years, whereas 9 new ones (Bogstranda BOG, Fugleberget FUG, Gnålodden GNA, Gåshamnoyra GAS, Hyttevika HYT, Lisbetdalen LIS, Ostrogradskijfjella OST, Treskelodden TRE and Wilczekodden WIL) were established within the Polish-Norwegian AWAKE-2 project. Three of the sites (BOG, GAS and OST) were damaged by polar bears, hence their measurement series are shorter. A substantial spatial diversity was found in the air temperature and relative humidity in the area, mostly influenced by elevation, type of surface and distance from the Greenland Sea's open water. During the year (July 2014 - June 2015), the areas of HYT (-1.1°C) and WIL (-1.9°C) were the warmest. Both sites are located on the west coast of the fjord. The HYT demonstrates the most favourable temperature conditions, being orographically sheltered from the east and its cold and dry air masses. The coldest sites were the mountain-top site of FUG (-5.9°C) and the glacier-located HG4 (-4.3°C). The low temperature at FUG resulted from its elevation (568 m a.s.l.), whereas at HG4 (184 m a.s.l) the glaciated surface also added up to the result. In the analysed period, the annual course of air temperature in the area had a clear minimum in February, when the lowest mean monthly values ranged from -9.4°C at HYT to -15.1°C at FUG. The highest temperature was recorded at all the sites in July, when its highest mean values were observed at GAS and HYT (6.1°C and 6.0°C, respectively), while the lowest occurred at FUG (2.4°C) and HG4 (3.1°C). The other meteorological element considered was relative humidity, which positively correlates with the course of air temperature. During the year, the most humid sites were those located at the mountain top (FUG) and on the Treskelen peninsula (TRE), towards the end of the fjord (94% and 91%, respectively). The lowest RH values were measured at HOR and HYT (80% in both). In the annual course, the lowest RH was observed in February with the lowest mean monthly values (74%) at HOR and HYT, and the highest at FUG (88%) and TRE (87%). As with air temperature, the highest relative humidity occurred in July. Its lowest mean values were recorded at HOR (87%), and the highest - at FUG (96%).

Kyanite-garnet gneisses of the Kåfjord Nappe - North Norwegian Caledonides: P-T conditions and monazite Th-U-Pb dating

NASA Astrophysics Data System (ADS)

Ziemniak, Grzegorz; Kośmińska, Karolina; Majka, Jarosław; Janák, Marian; Manecki, Maciej

2016-04-01

The Kåfjord Nappe is the part of the Skibotn Nappe Complex traditionally ascribed to the Upper Allochthon of the North Norwegian Caledonides. Pressure-temperature (P-T) conditions and metamorphic age of the Kåfjord Nappe are not well constrained, geochronological data are limited to a single Rb-Sr age of c. 440 Ma (Dangla et al. 1978). Metamorphic evolution of kyanite-garnet gneisses of the Kåfjord Nappe is presented here. The kyanite-garnet gneisses are associated with a few meters thick amphibolite lenses. The gneisses mainly consist of quartz, plagioclase, biotite, muscovite, garnet, kyanite, and rutile. Retrograde minerals are represented by sillimanite and chlorite. Garnet occurs as two textural types. Garnet-I forms euhedral porphyroblasts with multiple small inclusions. Profiles through garnet-I show chemical zonation in all components. The composition varies from Alm64-68Prp11-16Grs13-18Sps2-8 in the core to Alm68-70Prp17-18Grs10-13Sps1-3 in the rim. Garnet-II is subhedral to anhedral, its core is inclusion-rich, whereas rim contains only single inclusions. Chemical composition of garnet-II is similar to that of the garnet-I rim. P-T conditions have been estimated using the garnet-biotite-muscovite-plagioclase (GBPM) geothermobarometer (Holdaway, 2001; Wu, 2014). Calculated peak P-T metamorphic conditions are 610-625 °C and 7.6-8.2 kbar corresponding to the amphibolite facies conditions. Phase equilibrium modelling in the NCKFMMnASH system yields peak metamorphic conditions of c. 620 °C at 8 kbar. Growth conditions of garnet-I core modelled in the NCKFMMnASH system are c. 570 °C at 9.7 kbar. Chemical Th-U-total Pb monazite dating has been performed. Preliminary dating results from the kyanite-garnet gneiss of the Kåfjord Nappe yield an array of dates from 468 Ma to 404 Ma. There is a correlation between an increase of yttrium content and decrease of monazite single dates. Compositional maps confirm an increase of yttrium towards the rim of the monazite. This work is partially funded by AGH research grant no 11.11.140.319. References: Dangla, P., Damange, J. C., Ploquin, A., Quarnadel, J. M., Sonet, J., 1978. Donn'es geochronlogiques sur les Caledonides Scandinaves septentrionates (Troms, Norway du Nord). C. r. Acad. Sci. Paris, 286 D, 1653-1656. Holdaway, M. J., 2001. Recalibration of the GASP geobarometer in light of recent garnet and plagioclase activity models and versions of the garnet-biotite geothermometer. American Mineralogist, 86(10), 1117-1129. Wu, C. M., 2015. Revised empirical garnet-biotite-muscovite-plagioclase geobarometer in metapelites. Journal of Metamorphic Geology, 33(2), 167-176.

36 CFR 13.1326 - Snowmachines.

Code of Federal Regulations, 2014 CFR

2014-07-01

... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...) On Exit Glacier Road; (b) In parking areas; (c) On a designated route through the Exit Glacier...

36 CFR 13.1326 - Snowmachines.

Code of Federal Regulations, 2011 CFR

2011-07-01

... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...) On Exit Glacier Road; (b) In parking areas; (c) On a designated route through the Exit Glacier...

36 CFR 13.1326 - Snowmachines.

Code of Federal Regulations, 2013 CFR

2013-07-01

... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...) On Exit Glacier Road; (b) In parking areas; (c) On a designated route through the Exit Glacier...

36 CFR 13.1326 - Snowmachines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...) On Exit Glacier Road; (b) In parking areas; (c) On a designated route through the Exit Glacier...

Erosion of mountain plateaus along Sognefjord, Norway, constrained by cosmogenic nuclides

NASA Astrophysics Data System (ADS)

Andersen, Jane Lund; Egholm, David L.; Knudsen, Mads F.; Linge, Henriette; Jansen, John D.

2016-04-01

Norway is famous for its deeply incised, steep-sided fjords, carved out by glacial erosion. The high relief of the fjords stands in contrast to the extensive areas of relatively low relief found between the fjords. The origin and development of these low-relief areas remain debated. The classical interpretation relates them to a Mesozoic peneplanation surface, uplifted to the current high elevation in the early Cenozoic (e.g. Nesje, 1994). The validity of this interpretation has, however, been repeatedly questioned in recent times (e.g. Nielsen et al. 2009, Steer et al. 2012). Recent studies point instead to a significant impact of glacial and periglacial erosion processes on the long-term development of the low-relief surfaces (Egholm et al. 2015). Here, we present a large new dataset of in-situ produced cosmogenic 10Be and 26Al in bedrock and boulders from the high, flat summit surfaces along a transect from the coast to the inner parts of Sognefjorden in Norway. Our results indicate substantial glacial modification of the sampled low-relief surfaces within the last 50 ka. Close to the coast, at an elevation of around 700 meters, the cosmogenic nuclide signal was reset around the Younger Dryas due to extensive glacial erosion. Regarding the higher surfaces further inland, our results indicate a maximum cosmogenic nuclide inheritance of 20-30 ka prior to the last deglaciation. We do not find any signs of exceptional longevity of the low-relief landscape. In contrast, our results indicate that the low-relief areas were continuously eroded by glacial and periglacial processes in the Quaternary. Nesje & Whillans. Erosion of Sognefjord, Norway. Geomorphology 9(1), 33-45, 1994. Nielsen et al. The evolution of western Scandinavian topography: a review of Neogene uplift versus the ICE (isostasy-climate-erosion) hypothesis. Journal of Geodynamics 47(2), 72-95, 2009. Steer et al. Bimodal Plio-Quaternary glacial erosion of fjords and low-relief surfaces in Scandinavia. Nature Geoscience 5(9), 635-639, 2012. Egholm et al. The periglacial engine of mountain erosion - Part 2: Modelling large-scale landscape evolution. Earth Surface Dynamics 3(4), 463-482, 2015.

Increasing freshwater runoff and tidal action influences on spatial mixing patterns in Søndre Strømfjord, West Greenland.

NASA Astrophysics Data System (ADS)

Smiley, Crystal; Kamenos, Nick; Hoey, Trevor; Cottier, Finlo; Ellam, Rob

2015-04-01

Greenland Ice Sheet melt has the potential to affect global sea levels and the strength of the thermohaline circulation (THC). Investigating spatial mixing patterns of seawater in Greenlandic fjords can help reveal characteristics of changes in runoff from the GrIS; for example higher runoff may be associated with lower salinity within GrIS fjords, which can be recorded by palaeoenvironmental proxies (Kamenos et al 2012). The Kangerlussuaq Drainage Basin mirrors melt patterns of the whole GrIS and drains into Søndre Strømfjord, a 170km long fjord on the west coast of Greenland. Temperature and salinity profiles to 40m depth were obtained at 11 stations along Søndre Strømfjord during the 2014 melt season. Each station was sampled twice once at high KDB runoff and once at low KDB runoff. With increasing freshwater runoff, salinity decreased by 1.65 - 2.91 and temperature increased by 0.47oC- 2.34oC at each station over a 7 hour time period. Higher salinities occurred at low run-off. In addition, with increasing run-off, the disparity between surface and deeper water (30m) salinity became greater with a 19.3 difference between the surface and 30m. This information was integrated with oxygen and deuterium isotopic signatures collected at 10 m depth from each station to pinpoint the exact source of the runoff causing salinity reductions. With increasing freshwater runoff, the chemistry of the fjord exhibits an enrichment of the heavier isotope. δ18Ovsmow values enrich by 7.40 permil while δDvsmow enrich 53.26 permil. Our data shows a relationship between KDB runoff, salinity, and oxygen, hydrogen isotopic chemistry of Søndre Strømfjord, data that will enable further calibration of marine proxies of GrIS melt. References Kamenos, N.A, Hoey, T.B, Nienow, P., Fallick, A.E., & Claverie, T., 2012: Reconstructing Greenland Ice Sheet runoff using coralline algae; Geological Society of America, Geology, doi: 10.1130/G33405.1

Silver nanoparticles coated with natural polysaccharides as models to study AgNP aggregation kinetics using UV-Visible spectrophotometry upon discharge in complex environments.

PubMed

Lodeiro, Pablo; Achterberg, Eric P; Pampín, Joaquín; Affatati, Alice; El-Shahawi, Mohammed S

2016-01-01

This study provides quantitative information on the aggregation and dissolution behaviour of silver nanoparticles (AgNPs) upon discharge in fresh and sea waters, represented here as NaCl solutions of increasing ionic strength (up to 1M) and natural fjord waters. Natural polysaccharides, sodium alginate (ALG) and gum Arabic (GA), were used as coatings to stabilize the AgNPs and the compounds acted as models to study AgNP aggregation kinetics. The DLVO theory was used to quantitatively describe the interactions between the AgNPs. The stability of AgNPs was established using UV-Visible spectrophotometry, including unique information collected during the first seconds of the aggregaton process. Alginate coating resulted in a moderate stabilization of AgNPs in terms of critical coagulation concentration (~82mM NaCl) and a low dissolution of <10% total Ag in NaCl solutions up to 1M. Gum Arabic coated AgNPs were more strongly stabilized, with ~7-30% size increase up to 77mM NaCl, but only when the silver ion content initially present in solution was low (<10% total Ag). The ALG and GA coated AgNPs showed a strongly enhanced stability in natural fjord waters (ca. 5h required to reduce the area of the surface plasmon resonance band (SPRB) by two fold) compared with NaCl at an equivalent ionic strength (1-2min period for a two fold SPRB reduction). This is ascribed to a stabilizing effect from dissolved organic matter present in natural fjord waters. Interestingly, for AgNP-GA solutions with 40% of total silver present as unreacted silver ions in the NP stock solution, fast aggregation kinetics were observed in NaCl solutions (SPRB area was reduced by ca. 50% within 40-150min), with even more rapid removal in fjord waters, attributed to the high amount of silver-chloride charged species, that interact with the NP coating and/or organic matter and reduce the NPs stabilization. Copyright © 2015 Elsevier B.V. All rights reserved.

From Carbonatite to Ikaite: How high-T carbonates are transformed into low-T carbonate minerals in SW Greenland

NASA Astrophysics Data System (ADS)

Stockmann, G. J.; Tollefsen, E.; Ranta, E.; Skelton, A.; Sturkell, E.; Lundqvist, L.

2015-12-01

The 1300 Ma Grønnedal-Íka igneous complex in southwest Greenland comprises nepheline syenites and carbonatites. It belongs to a suite of intrusions formed 1300-1100 Ma ago referred to as the Gardar period. In modern time (the last ca. 8000 years), fluid-rock interactions involving the nepheline syenites and carbonatites gives rise to about one thousand submarine columns made of the rare low-T mineral ikaite (CaCO3x6H2O). The columns are found in a shallow, narrow fjord named Ikka Fjord and their distribution clearly follows the outcrop of the Grønnedal-Íka complex. When meteoric water percolates through the highly fractured complex, a sodium carbonate solution of pH 10 is formed through hitherto unknown fluid-rock reactions. This basic solution seeps up through fractures at the bottom of Ikka Fjord and when mixed with seawater, the mineral ikaite is formed. As the seepage water has a lower density than seawater, there is an upwards flow that creates columns. What is peculiar about ikaite is its limited stability making it unstable above +6 °C. Isotopic studies of ikaite reveal a seawater origin for the Ca2+ ions, and the carbonatite being the most likely source for the CO32- ions. The carbonatite is mainly of søvite composition (CaCO3) with high contents of siderite and ankerite in certain areas. The nepheline syenites contain Na,K-rich minerals like nepheline, alkali-feldspar, aegirine-augite, katophorite and biotite. Nepheline is mainly replaced by muscovite, and aegirine-augite partly by chlorite, which could release sodium into solution. A dolerite dyke of unknown age prompted extensive mineralization of magnetite by activating hydrothermal fluid convection. The fluid interacted with the carbonatite, replacing siderite and ankerite by magnetite and later hematite. In a newly launched project at Stockholm University, we are trying to unravel the chemical reactions taking place inside the Grønnedal-Íka igneous complex leading to the formation of the sodium carbonate solution issuing in Ikka Fjord.

Oxic to anoxic transition in bottom waters during formation of the Citronen Fjord sediment-hosted Zn-Pb deposit, North Greenland

USGS Publications Warehouse

Slack, John F.; Rosa, Diogo; Falck, Hendrik

2015-01-01

Bulk geochemical data acquired for host sedimentary rocks to the Late Ordovician Citronen Fjord sediment-hosted Zn-Pb deposit in North Greenland constrain the redox state of bottom waters prior to and during sulphide mineralization. Downhole profiles for one drill core show trends for redox proxies (MnO, Mo, Ce anomalies) that suggest the local basin bottom waters were initially oxic, changing to anoxic and locally sulphidic concurrent with sulphide mineralization. We propose that this major redox change was caused by two broadly coeval processes (1) emplacement of debris-flow conglomerates that sealed off the basin from oxic seawater, and (2) venting of reduced hydrothermal fluids into the basin. Both processes may have increased H2S in bottom waters and thus prevented the oxidation of sulphides on the sea floor.

Vegetative Succession in Recently Deglaciated Land in Kenai Fjords National Park

NASA Astrophysics Data System (ADS)

Green, C.; Klein, A. G.; Cairns, D. M.

2017-12-01

Poleward vegetation expansion has affected Alaska for decades and due to recently increased rates of warming, the expansion will accelerate. Glacial recession in Kenai Fjords National Park has exposed previously ice-covered land with vegetation succession occurring just a few years following glacial retreat. Land cover changes in recently deglaciated areas are affected by surface-air interactions, temperature gradients, and ecosystem development. Using satellite images from Landsat 5, 7, and 8 and the previous extents of four retreating glaciers from 1985 to 2015 within Kenai Fjords National Park, this study examines the relationship between deglaciation rates and vegetation greening. The glaciers, Exit (-15.04 m/yr), Petrof (-31.12 m/yr), Lowell (-33.14 m/yr), and Yalik (-51.32 m/yr) were selected based on their location, whether they were land or lake terminating, and their average retreat rate measured between 1985 and 2015. These glaciers have also been extensively studied. Combining historic glacier extents with 371 summer (JJA) Landsat images gathered from Google's Earth Engine platform we identified annual summer changes in NDVI of locations that were deglaciated between 1985, 1995, 2005, and 2015. Summer temperature maximums were determined to be more correlated with deglaciation, as measured using NDSI, than mean summer temperatures. Using NDVI, heightened deglaciation rates were found to be reasonably correlated with vegetation succession. The faster retreating glaciers, Lowell and Yalik, exhibited higher mean and maximum rates of increase of NDVI in their terminus areas than Exit and Petrof, the two slower retreating glaciers.

The Hornsund fjord - modeling of the general circulation, heat exchange and water masses transport.

NASA Astrophysics Data System (ADS)

Przyborska, Anna; Jakacki, Jaromir; Kosecki, Szymon; Sundfjord, Arild

2015-04-01

The MIKE3D hydrodynamic model has been implemented for diagnosis an ecosystem status in the most southern fjord of the Svalbard Archipelago. The model is based on MIKE 3 Flow Model FM that uses flexible mesh grid. The spatial discretization in solutions of equations is performed by the finite element method. The regional scale of the model implicated implementation of external data at the lateral boundary region. In our case Flather's boundary condition let us to force the model with combined information. At the same time tidal ordinate and barotropic component of velocity that reflects the West Spitsbergen Current are implemented. Also salinity and temperature were nested at the boundary area. The upper boundary conditions was also introduced. The data for the boundary were taken from Global Tide Model (all tidal components), an 800 m ROMS simulation of the Svalbard area made by the Norwegian Institute of Marine Research (bartoropic velocities, temperature and salinity), European Centre for Medium Weather Forecast (ECMWF) and also from Global Data Assimilation System (GDAS). Implemented model was validated and the mean circulation and its seasonal variability will be presented. Also influence of the shelf water masses on the fjord will be discussed. Fresh water transport from glaciers, run off and snow will be estimated. Results are based on 5 years simulation (2005-2010) This work was partially performed in the frame of the projects GAME (DEC-2012/04/A/NZ8/00661) and AWAKE2 (Pol-Nor/198675/17/2013)

A High-Resolution Record of Warm Water Inflow and Iceberg Calving in Upernavik Isfjord During the Past 150 Years.

NASA Astrophysics Data System (ADS)

Vermassen, F.; Andresen, C. S.; Sabine, S.; Holtvoeth, J.; Cordua, A. E.; Wangner, D. J.; Dyke, L. M.; Kjaer, K. H.; Kokfelt, U.; Haubner, K.

2016-12-01

There is a growing body of evidence demonstrating that changes in warm water inflow to Greenlandic fjords are linked to the rapid retreat of marine-terminating outlet glaciers. This process is thought to be responsible for a substantial component of the increased mass loss from the Greenland Ice Sheet over the last two decades. Sediment cores from glaciated fjords provide high-resolution sedimentological and biological proxy records which can be used to evaluate the interplay of warm water inflow and glacier calving over recent time scales. In this study, multiple short cores ( 2 m) from Upernavik Isfjord, West Greenland, were analysed to establish a multi-proxy record of glacier behaviour and oceanographic conditions that spans the past 150 years. The down-core variation in the amount of ice-rafted debris reveals periods of increased glacier calving, and biomarker proxies are used to reconstruct variability in the inflow of warm, Atlantic-sourced water to the fjord. Measurements of the sortable silt grain size are used to reconstruct bottom-current strength; periods of vigorous current flow are assumed to be due to enhanced warm water inflow. Finally, a record of glacier terminus position changes, derived from historical observations and satellite imagery, allows comparison of our new proxy records with the retreat of the ice margin from 1849 onwards. We use these data to assess the relative importance of mechanisms controlling the (rapid) retreat of marine-terminating glaciers in Upernavik Isfjord.

Fjord light regime: Bio-optical variability, absorption budget, and hyperspectral light availability in Sognefjord and Trondheimsfjord, Norway

NASA Astrophysics Data System (ADS)

Mascarenhas, V. J.; Voß, D.; Wollschlaeger, J.; Zielinski, O.

2017-05-01

Optically active constituents (OACs) in addition to water molecules attenuate light via processes of absorption and scattering and thereby determine underwater light availability. An analysis of their optical properties helps in determining the contribution of each of these to light attenuation. With an aim to study the bio-optical variability, absorption budget and 1% spectral light availability, hydrographical (temperature and salinity), and hyperspectral optical (downwelling irradiance and upwelling radiance) profiles were measured along fjord transects in Sognefjord and Trondheimsfjord, Norway. Optical water quality observations were also performed using Secchi disc and Forel-Ule scale. In concurrence, water samples were collected and analyzed via visible spectrophotometry, fluorometry, and gravimetry to quantify and derive inherent optical properties of the water constituents. An absorption model (R2 = 0.91, n = 36, p < 0.05) as a function of OACs is developed for Sognefjord using multiple regression analysis. Influenced by glacial meltwater, Sognefjord had higher concentration of inorganic suspended matter, while Trondheimsfjord had higher concentrations of CDOM. Increase in turbidity caused increased attenuation of light upstream, as a result of which the euphotic depth decreased from outer to inner fjord sections. Triangular representation of absorption budget revealed dominant absorption by CDOM at 443-555 nm, while that by phytoplankton at 665 nm. Sognefjord however exhibited much greater optical complexity. A significantly strong correlation between salinity and acdom440 is used to develop an algorithm to estimate acdom440 using salinity in Trondheimsfjord.

Spatially Estimating Disturbance of Harbor Seals (Phoca vitulina)

PubMed Central

Jansen, John K.; Brady, Gavin M.; Ver Hoef, Jay M.; Boveng, Peter L.

2015-01-01

Tidewater glacial fjords in Alaska provide habitat for some of the largest aggregations of harbor seals (Phoca vitulina), with calved ice serving as platforms for birthing and nursing pups, molting, and resting. These fjords have also been popular destinations for tour ships for more than a century, with dramatic increases in vessel traffic since the 1980s. Seals on ice are known to flush into the water when approached by tour ships, but estimating the exposure to disturbance across populations is difficult. Using aerial transect sampling while simultaneously tracking vessel movements, we estimated the spatial overlap between seals on ice and cruise ships in Disenchantment Bay, Alaska, USA. By integrating previously estimated rates of disturbance as a function of distance with an ‘intensity surface’ modeled spatially from seal locations in the surveys, we calculated probabilities of seals flushing during three separate ship visits. By combining our estimate of seals flushed with a modeled estimate of the total fjord population, we predict that up to 14% of the seals (up to 11% of pups) hauled out would have flushed into the water, depending on the route taken by ships relative to seal aggregations. Such high potential for broad-scale disturbance by single vessels (when up to 4 ships visit per day) was unexpected and underscores the need to 1) better understand long-term effects of disturbance; 2) regularly monitor populations exposed to high vessel traffic; and 3) develop conservation measures to reduce seal-ship overlap. PMID:26132083

Subtidal circulation in a deep-silled fjord: Douglas Channel, British Columbia

NASA Astrophysics Data System (ADS)

Wan, Di; Hannah, Charles G.; Foreman, Michael G. G.; Dosso, Stan

2017-05-01

Douglas Channel, a deep fjord on the west coast of British Columbia, Canada, is the main waterway in the fjord system that connects the town of Kitimat to Queen Charlotte Sound and Hecate Strait. A 200 m depth sill divides Douglas Channel into an outer and an inner basin. This study examines the low-frequency (from seasonal to meteorological bands) circulation in Douglas Channel from data collected at three moorings deployed during 2013-2015. The deep flows are dominated by a yearly renewal that takes place from May/June to early September. A dense bottom layer with a thickness of 100 m that cascades through the system at the speed of 0.1-0.2 m s-1, which is consistent with gravity currents. Estuarine flow dominates the circulation above the sill depth, and the observed landward net volume flux suggests that it is necessary to include the entire complex channel network to fully understand the estuarine circulation in the system. The influence of the wind forcing on the subtidal circulation is not only at the surface, but also at middepth. The along-channel wind dominates the surface current velocity fluctuations and the sea level response to the wind produces a velocity signal at 100-120 m in the counter-wind direction. Overall, the circulation in the seasonal and the meteorological bands is a mix of estuarine flow, direct wind-driven flow, and the barotropic and baroclinic responses to changes to the surface pressure gradient caused by the wind stress.

Surfacing behavior and gas release of the physostome sprat (Sprattus sprattus) in ice-free and ice-covered waters.

PubMed

Solberg, Ingrid; Kaartvedt, Stein

2014-01-01

Upward-facing echosounders that provided continuous, long-term measurements were applied to address the surfacing behavior and gas release of the physostome sprat ( Sprattus sprattus ) throughout an entire winter in a 150-m-deep Norwegian fjord. During ice-free conditions, the sprat surfaced and released gas bubbles at night with an estimated surfacing rate of 3.5 times per fish day -1 . The vertical swimming speeds during surfacing were considerably higher (~10 times) than during diel vertical migrations, especially when returning from the surface, and particularly when the fjord was not ice covered. The sprat released gas a few hours after surfacing, suggesting that the sprat gulped atmospheric air during its excursions to the surface. While the surface activity increased after the fjord became ice covered, the records of gas release decreased sharply. The under-ice fish then displayed a behavior interpreted as "searching for the surface" by repeatedly ascending toward the ice, apparently with limited success of filling the swim bladder. This interpretation was supported by lower acoustic target strength in ice-covered waters. The frequent surfacing behavior demonstrated in this study indicates that gulping of atmospheric air is an important element in the life of sprat. While at least part of the population endured overwintering in the ice-covered habitat, ice covering may constrain those physostome fishes that lack a gas-generating gland in ways that remain to be established.

DMI's Baltic Sea Coastal operational forecasting system

NASA Astrophysics Data System (ADS)

Murawski, Jens; Berg, Per; Weismann Poulsen, Jacob

2017-04-01

Operational forecasting is challenged with bridging the gap between the large scales of the driving weather systems and the local, human scales of the model applications. The limit of what can be represented by local model has been continuously shifted to higher and higher spatial resolution, with the aim to better resolve the local dynamic and to make it possible to describe processes that could only be parameterised in older versions, with the ultimate goal to improve the quality of the forecast. Current hardware trends demand a str onger focus on the development of efficient, highly parallelised software and require a refactoring of the code with a solid focus on portable performance. The gained performance can be used for running high resolution model with a larger coverage. Together with the development of efficient two-way nesting routines, this has made it possible to approach the near-coastal zone with model applications that can run in a time effective way. Denmarks Meteorological Institute uses the HBM(1) ocean circulation model for applications that covers the entire Baltic Sea and North Sea with an integrated model set-up that spans the range of horizontal resolution from 1nm for the entire Baltic Sea to approx. 200m resolution in local fjords (Limfjord). For the next model generation, the high resolution set-ups are going to be extended and new high resolution domains in coastal zones are either implemented or tested for operational use. For the first time it will be possible to cover large stretches of the Baltic coastal zone with sufficiently high resolution to model the local hydrodynamic adequately. (1) HBM stands for HIROMB-BOOS-Model, whereas HIROMB stands for "High Resolution Model for the Baltic Sea" and BOOS stands for "Baltic Operational Oceanography System".

Holocene variations in mineral and grain-size composition along the East Greenland glaciated margin (ca 67°–70°N): local versus long-distance sediment transport

USGS Publications Warehouse

Andrews, John T.; Jennings, Anne E.; Coleman, George C.; Eberl, Dennis D.

2010-01-01

Quantitative X-Ray Diffraction (qXRD) analysis of the <2 mm sediment fraction from surface (sea floor) samples, and marine sediment cores that span the last 10-12 cal ka BP, are used to describe spatial and temporal variations in non-clay mineral compositions for an area between Kangerlussuaq Trough and Scoresby Sund (???67??-70??N), East Greenland. Bedrock consists primarily of an early Tertiary alkaline complex with high weight% of pyroxene and plagioclase. Farther inland and to the north, the bedrock is dominantly felsic with a high fraction of quartz and potassium feldspars. Principal Component (PC) analysis of the non-clay sediment compositions indicates the importance of quartz and pyroxene as compositional end members, with an abrupt shift from quartz and k-feldspar dominated sediments north of Scoresby Sund to sediments rich in pyroxene and plagioclase feldspars offshore from the early Tertiary basaltic outcrop. Coarse (<2 mm or <1 mm) ice-rafted sediments are largely absent from the trough sediments between ???8 and 5 cal ka BP, but then increase in the last 4 cal ka BP. Compositional unmixing of the sediments in Grivel Basin and Kangerlussuaq Trough indicate the dominance of local over long distance sediment sources, with pulses of sediment from tidewater glaciers in Kangerlussuaq and Nansen fjords reaching the inner shelf during the Neoglaciation. The change in IRD is more dramatic in the sediment grain-size proxies than in the quartz wt%. Forty to seventy percent of the variance in the quartz records from either side of Denmark Strait is explained by low frequency trends, but the data from the Grivel Basin, East Greenland, are distinctly different, with an approximate 2500 yr periodicity. ?? 2010 Elsevier Ltd.

Seasonal variability of primary production in a fjord ecosystem of the Chilean Patagonia: Implications for the transfer of carbon within pelagic food webs

NASA Astrophysics Data System (ADS)

Montero, Paulina; Daneri, Giovanni; González, Humberto E.; Iriarte, Jose Luis; Tapia, Fabián J.; Lizárraga, Lorena; Sanchez, Nicolas; Pizarro, Oscar

2011-03-01

We characterized the seasonal cycle of productivity in Reloncaví Fjord (41°30'S), Chilean Patagonia. Seasonal surveys that included measurements of gross primary production, community respiration, bacterioplankton secondary production, and sedimentation rates along the fjord were combined with continuous records of water-column temperature variability and wind forcing, as well as satellite-derived data on regional patterns of wind stress, sea surface temperatures, and surface chlorophyll concentrations. The hydrography and perhaps fjord productivity respond to the timing and intensity of wind forcing over a larger region. Seasonal changes in the direction and intensity of winds, along with a late-winter improvement in light conditions, may determine the timing of phytoplankton blooms and potentially modulate productivity cycles in the region. Depth-integrated gross primary production estimates were higher (0.4-3.8 g C m -2 d -1) in the productive season (October, February, and May), and lower (0.1-0.2 g C m -2 d -1) in the non-productive season (August). These seasonal changes were also reflected in community respiration and bacterioplankton production rates, which ranged, respectively, from 0.3 to 4.8 g C m -2 d -1 and 0.05 to 0.4 g C m -2 d -1 during the productive and non-productive seasons and from 0.05 to 0.6 g C m -2 d -1 and 0.05 to 0.2 g C m -2 d -1 during the same two periods. We found a strong, significant correlation between gross primary production and community respiration (Spearman, r=0.95; p<0.001; n=12), which suggests a high degree of coupling between the synthesis of organic matter and its usage by the planktonic community. Similarly, strong correlations were found between bacterioplankton secondary production and both gross primary production (Spearman, r=0.7, p<0.05, n=9) and community respiration (Spearman, r=0.8, p<0.05, n=9), indicating that bacterioplankton may be processing an important fraction (8-59%) of the organic matter produced by phytoplankton in Reloncaví Fjord. In winter, bacterial carbon utilization as a percentage of gross primary production was >100%, suggesting the use of allochthonous carbon sources by bacterioplankton when the levels of gross primary production are low. Low primary production rates were associated with a greater contribution of small cells to autotrophic biomass, highlighting the importance of small-sized plankton and bacteria for carbon cycling and fluxes during the less productive winter months. Fecal pellet sedimentation was minimal during this period, also suggesting that most of the locally produced organic carbon is recycled within the microbial loop. During the productive season, on the other hand, the area exhibited a great potential to export organic matter, be it to higher trophic levels or vertically towards the bottom.

Recent variability in the Atlantic water intrusion and water masses in Kongsfjorden, an Arctic fjord

NASA Astrophysics Data System (ADS)

Divya, David T.; Krishnan, K. P.

2017-03-01

The present study reports high inter-annual variability in the water masses and in the intrusion of Atlantic origin waters in Kongsfjorden from 2000 to 2013 using both the historical (2000-2010 summers) and recent CTD measurements (2011-2013 summer/fall). An earlier intrusion of Atlantic Water (AW) into Kongsfjorden was observed in the contemporary years. An overall summertime subsurface warming is evident from the maximum September AW temperature in 2011 (4.8 °C), 2012 (5.8 °C) and 2013 (7 °C). The combination of a compensating surface flow to the subsurface intrusion of AW and the strong southeasterly surface winds during the peak summer, resulted in a corresponding net outflow of the surface fresh water layer from Kongsfjorden. This led to the decreased freshwater volume inside the fjord during 2013 (1 km3) compared to 2011 (3.1 km3) and 2012 (2.3 km3).

Reproduction of the cold-water coral Primnoella chilensis (Philippi, 1894)

NASA Astrophysics Data System (ADS)

Rossin, Ashley M.; Waller, Rhian G.; Försterra, Gunter

2017-07-01

This study examined the reproduction of a cold-water coral, Primnoella chilensis (Philippi, 1894) from the Comau and Reñihué fjords in Chilean Patagonia. Samples were collected in September and November of 2012 and April, June, and September of 2013 from three sites within the two fjords. The sexuality, reproductive mode, spermatocyst stage, oocyte size, and fecundity were determined using histological techniques. This species is gonochoristic with one aberrant hermaphrodite identified in this study. Reproduction was found to be seasonal, with the initiation of oogenesis in September and suggested a broadcast spawning event between June and September. The maximum oocyte size was 752.96 μm, suggesting a lecithotrophic larvae. The maximum fecundity was 36 oocytes per polyp. Male individuals were only found in April and June. In June, all four spermatocyst stages were present. This suggests that spermatogenesis requires less time than oogenesis in P. chilensis.

High export of dissolved silica from the Greenland Ice Sheet

NASA Astrophysics Data System (ADS)

Meire, L.; Meire, P.; Struyf, E.; Krawczyk, D. W.; Arendt, K. E.; Yde, J. C.; Juul Pedersen, T.; Hopwood, M. J.; Rysgaard, S.; Meysman, F. J. R.

2016-09-01

Silica is an essential element for marine life and plays a key role in the biogeochemistry of the ocean. Glacial activity stimulates rock weathering, generating dissolved silica that is exported to coastal areas along with meltwater. The magnitude of the dissolved silica export from large glacial areas such as the Greenland Ice Sheet is presently poorly quantified and not accounted for in global budgets. Here we present data from two fjord systems adjacent to the Greenland Ice Sheet which reveal a large export of dissolved silica by glacial meltwater relative to other macronutrients. Upscaled to the entire Greenland Ice Sheet, the export of dissolved silica equals 22 ± 10 Gmol Si yr-1. When the silicate-rich meltwater mixes with upwelled deep water, either inside or outside Greenland's fjords, primary production takes place at increased silicate to nitrate ratios. This likely stimulates the growth of diatoms relative to other phytoplankton groups.

Greenland as seen by the STS-66 shuttle Atlantis

NASA Technical Reports Server (NTRS)

1994-01-01

This north-looking view of southwestern Greenland was taken in November, 1994, and shows numerous indentations, many of which contain small settlements. These fjords were carved by the glaciers of the last ice age 10,000 years ago. Even today, the ice in the center of Greenland is nearly 3,500 meters (11,000 feet) thick and great rivers of ice continuously flow down toward the sea, where they melt or break off as icebergs. Some Icebergs exceed the size of small islands, weigh several million tons, and rise several hundred feet above the sea surface. Cape Farewell is visible toward the bottom right of the view. Julianehab Bay and the Bredev fjord can be seen toward the center of the photograph. Godthab, the main settlement on Greenland, is barely visible to the north of the Frederikeshabs Icefield near the left center of the view.

Greenland as seen by the STS-66 shuttle Atlantis

NASA Image and Video Library

1994-11-14

This north-looking view of southwestern Greenland was taken in November, 1994, and shows numerous indentations, many of which contain small settlements. These fjords were carved by the glaciers of the last ice age 10,000 years ago. Even today, the ice in the center of Greenland is nearly 3,500 meters (11,000 feet) thick and great rivers of ice continuously flow down toward the sea, where they melt or break off as icebergs. Some Icebergs exceed the size of small islands, weigh several million tons, and rise several hundred feet above the sea surface. Cape Farewell is visible toward the bottom right of the view. Julianehab Bay and the Bredev fjord can be seen toward the center of the photograph. Godthab, the main settlement on Greenland, is barely visible to the north of the Frederikeshabs Icefield near the left center of the view.

Simulating run-up on steep slopes with operational Boussinesq models; capabilities, spurious effects and instabilities

NASA Astrophysics Data System (ADS)

Løvholt, F.; Lynett, P.; Pedersen, G.

2013-06-01

Tsunamis induced by rock slides plunging into fjords constitute a severe threat to local coastal communities. The rock slide impact may give rise to highly non-linear waves in the near field, and because the wave lengths are relatively short, frequency dispersion comes into play. Fjord systems are rugged with steep slopes, and modeling non-linear dispersive waves in this environment with simultaneous run-up is demanding. We have run an operational Boussinesq-type TVD (total variation diminishing) model using different run-up formulations. Two different tests are considered, inundation on steep slopes and propagation in a trapezoidal channel. In addition, a set of Lagrangian models serves as reference models. Demanding test cases with solitary waves with amplitudes ranging from 0.1 to 0.5 were applied, and slopes were ranging from 10 to 50°. Different run-up formulations yielded clearly different accuracy and stability, and only some provided similar accuracy as the reference models. The test cases revealed that the model was prone to instabilities for large non-linearity and fine resolution. Some of the instabilities were linked with false breaking during the first positive inundation, which was not observed for the reference models. None of the models were able to handle the bore forming during drawdown, however. The instabilities are linked to short-crested undulations on the grid scale, and appear on fine resolution during inundation. As a consequence, convergence was not always obtained. It is reason to believe that the instability may be a general problem for Boussinesq models in fjords.

Microeukaryote Community Patterns along an O2/H2S Gradient in a Supersulfidic Anoxic Fjord (Framvaren, Norway)†

PubMed Central

Behnke, Anke; Bunge, John; Barger, Kathryn; Breiner, Hans-Werner; Alla, Victoria; Stoeck, Thorsten

2006-01-01

To resolve the fine-scale architecture of anoxic protistan communities, we conducted a cultivation-independent 18S rRNA survey in the superanoxic Framvaren Fjord in Norway. We generated three clone libraries along the steep O2/H2S gradient, using the multiple-primer approach. Of 1,100 clones analyzed, 753 proved to be high-quality protistan target sequences. These sequences were grouped into 92 phylotypes, which displayed high protistan diversity in the fjord (17 major eukaryotic phyla). Only a few were closely related to known taxa. Several sequences were dissimilar to all previously described sequences and occupied a basal position in the inferred phylogenies, suggesting that the sequences recovered were derived from novel, deeply divergent eukaryotes. We detected sequence clades with evolutionary importance (for example, clades in the euglenozoa) and clades that seem to be specifically adapted to anoxic environments, challenging the hypothesis that the global dispersal of protists is uniform. Moreover, with the detection of clones affiliated with jakobid flagellates, we present evidence that primitive descendants of early eukaryotes are present in this anoxic environment. To estimate sample coverage and phylotype richness, we used parametric and nonparametric statistical methods. The results show that although our data set is one of the largest published inventories, our sample missed a substantial proportion of the protistan diversity. Nevertheless, statistical and phylogenetic analyses of the three libraries revealed the fine-scale architecture of anoxic protistan communities, which may exhibit adaptation to different environmental conditions along the O2/H2S gradient. PMID:16672511

Increasing Freshwater Runoff and Tidal Action Influences on Spatial Mixing Patterns in Søndre Strømfjord, West Greenland

NASA Astrophysics Data System (ADS)

Smiley, C. R.; Kamenos, N.; Hoey, T.; Cottier, F.; Ellam, R. M.

2014-12-01

Greenland Ice Sheet melt has the potential to affect global sea levels and the strength of the thermohaline circulation (THC). Investigating spatial mixing patterns of seawater in Greenlandic fjords can help reveal characteristics of changes in runoff from the GrIS; for example higher runoff may be associated with lower salinity within GrIS fjords, which can be recorded by palaeoenvironmental proxies (Kamenos et al 2012). The Kangerlussuaq Drainage Basin mirrors melt patterns of the whole GrIS and drains into Søndre Strømfjord, a 170km long fjord on the west coast of Greenland. Temperature and salinity profiles to 40m depth were obtained at 11 stations along Søndre Strømfjord during the 2014 melt season. Each station was sampled twice once at high KDB runoff and once at low KDB runoff. With increasing freshwater runoff, salinity decreases by 1.65 - 2.91 at each station over a 7 hour time period. Higher salinities occur at low run-off. In addition, with increasing run-off, the disparity between surface and deeper water (30m) becomes greater with a 19.3 difference between the surface and 30m. With higher KDB runoff temperature increases by 0.47oC - 2.34oC. This information will be integrated with oxygen and deuterium isotope patterns to pinpoint the exact source of the runoff causing salinity reductions. Our data show a relationship between KDB runoff and salinity of Søndre Strømfjord, data that will enable further calibration of marine proxies of GrIS melt.

Distribution of siphonophores, chaetognaths, euphausiids and oceanographic conditions in the fjords and channels of southern Chile

NASA Astrophysics Data System (ADS)

Palma, Sergio; Silva, Nelson

2004-03-01

Interior waters of the fjords and channels of southern Chile (41.5°S-56°S) receive inputs of Subantarctic Water, Equatorial Subsuperficial Water and Western Pacific Subsurface Water from the adjacent Pacific Ocean by means of numerous connecting channels that lead inward from the ocean margin. These waters become mixed in the interior zone with freshwater from precipitation, river flow, and meltwater from cordilleran glaciers. A two-layered positive estuarine circulation becomes established, with a superficial layer having a net movement towards the adjacent ocean, and a deep layer with net movement towards the fjords. The biomass of the interior waters is composed principally of planktonic crustaceans (copepods and euphausiids), chaetognaths, and gelatinous carnivores. In a southerly direction, decreases are observed in biomass, in relative abundance, and in species diversity of siphonophores, chaetognaths, and euphausiids. Only a few species have been able to adapt successfully to the extreme oceanographic conditions typical of the region, reflected in dominant monospecific populations such as Muggiaea atlantica, Sagitta tasmanica, and Euphausia vallentini. The zooplankton fauna of interior waters, characterized by its low degree of specific richness, is made up of a mixture of species typical of Subantarctic Water (Sagitta tasmanica, S. decipiens, Euphausia lucens, Nematoscelis megalops, Thysanoessa gregaria), antarctic water (Pyrosthephos vanhoeffeni, Dimophyes arctica, Sagitta marri, S. gazellae, Eukrohnia hamata, E. bathyantarctica, Euphausia vallentini), temperate and warm epipelagic waters (Eudoxoides spiralis, Lensia conoidea, Chelophyes appendiculata, Muggiaea atlantica, Sphaeronectes gracilis, S. fragilis, Abylopsis tetragona, Sagitta enflata), and mesopelagic water (Physophora hydrostatica, Stylocheiron maximum, Vogtia pentacantha, V. serrata).

Invisible polynyas: Modulation of fast ice thickness by ocean heat flux on the Canadian polar shelf

NASA Astrophysics Data System (ADS)

Melling, Humfrey; Haas, Christian; Brossier, Eric

2015-02-01

Although the Canadian polar shelf is dominated by thick fast ice in winter, areas of young ice or open water do recur annually at locations within and adjacent to the fast ice. These polynyas are detectable by eye and sustained by wind or tide-driven ice divergence and ocean heat flux. Our ice-thickness surveys by drilling and towed electromagnetic sounder reveal that visible polynyas comprise only a subset of thin-ice coverage. Additional area in the coastal zone, in shallow channels and in fjords is covered by thin ice which is too thick to be discerned by eye. Our concurrent surveys by CTD reveal correlation between thin fast ice and above-freezing seawater beneath it. We use winter time series of air and ocean temperatures and ice and snow thicknesses to calculate the ocean-to-ice heat flux as 15 and 22 W/m2 at locations with thin ice in Penny Strait and South Cape Fjord, respectively. Near-surface seawater above freezing is not a sufficient condition for ocean heat to reach the ice; kinetic energy is needed to overcome density stratification. The ocean's isolation from wind under fast ice in winter leaves tides as the only source. Two tidal mechanisms driving ocean heat flux are discussed: diffusion via turbulence generated by shear at the under-ice and benthic boundaries, and the internal hydraulics of flow over topography. The former appears dominant in channels and the coastal zone and the latter in some silled fjords where and when the layering of seawater density permits hydraulically critical flow.

Stable isotope signatures and element stoichiometry of Fucus vesiculosus as indicators for environmental conditions in the Kiel Bight, Baltic Sea

NASA Astrophysics Data System (ADS)

Winde, Vera; Mahler, Annika; Voss, Maren; Böttcher, Michael E.

2014-05-01

In the frame of the BMBF project BIOACID II we aim for an understanding of the natural distribution and variation of isotopic composition and C-N-S stoichiometry in Fucus vesiculosus growing around the coast line of the Kiel fjord (part of the Kiel bight). Environmental conditions (aquatic chemistry, temperature, salinity) were monitored, too. Some changes in aquatic chemistry are related to stress factors like human activity (e.g., waste input) and further factors leading to specific changes in the composition of Fucus vesiculosus. Sampling was carried out at different stations at the west and east coast of the Kiel Fjord. For each sampling station the aquatic chemistry (TA, pH, salinity, d13C(DIC), main and trace elements and nutrients) as well as the composition of the Fucus organic tissues (stoichiometry and stable isotope composition of carbon, nitrogen) are analysed. The Fucus tissue was sampled in three size classes (small, medium, large). It is shown, that Fucus vesiculosus indicates clear differences in the N contents and stable isotopes between the west and the east site of the Kiel Fjord. Stable nitrogen isotope signatures in Fucus vesiculosus, are useful proxies to identify the influence factors in the Fucus habitat. From the data it is obtained that the influence of human activity (wastewater treatment plant, harbour), small stream and drainage channels, which flow from the near coastal area into the bight, leads to different Fucus vesiculosus compositions. In future work, it is intended to extend the investigation to trace element signatures to further estimate environmental impacts.

Gender in physics in Denmark

NASA Astrophysics Data System (ADS)

Niss, Kristine; Nordström, Birgitta; Bearden, Ian; Grage, Mette M.-L.

2013-03-01

More women than men get a college degree in Denmark. However, Denmark still has very gender-separated labor market, and in physics only 10% of the university professors are women. Measures are needed to get a more balanced gender distribution among university physicists at all levels in Denmark.

36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

Code of Federal Regulations, 2010 CFR

2010-07-01

... operator of utilizing such measures and the effect of these costs on the long- and short-term economic viability of the operations. (3) The authorized officer shall not require implementation of mitigating...

36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

Code of Federal Regulations, 2014 CFR

2014-07-01

... operator of utilizing such measures and the effect of these costs on the long- and short-term economic viability of the operations. (3) The authorized officer shall not require implementation of mitigating...

36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

Code of Federal Regulations, 2011 CFR

2011-07-01

... operator of utilizing such measures and the effect of these costs on the long- and short-term economic viability of the operations. (3) The authorized officer shall not require implementation of mitigating...

36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

Code of Federal Regulations, 2013 CFR

2013-07-01

... operator of utilizing such measures and the effect of these costs on the long- and short-term economic viability of the operations. (3) The authorized officer shall not require implementation of mitigating...

36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

Code of Federal Regulations, 2012 CFR

2012-07-01

... operator of utilizing such measures and the effect of these costs on the long- and short-term economic viability of the operations. (3) The authorized officer shall not require implementation of mitigating...

Where on Earth...? MISR Mystery Image Quiz #3:Lofoten Islands, Norway

NASA Image and Video Library

2001-09-26

Lofoten Islands, Norway. Norway is deeply indented by fjords, rises precipitously to high plateaus, and is united with the ocean by numerous islands. This image from NASA Terra satellite is MISR Mystery Image Quiz #2.

Workshop on Early Crustal Genesis: The World's Oldest Rocks

NASA Technical Reports Server (NTRS)

Ashwal, L. D. (Editor)

1986-01-01

Topics addressed include: a general review of Precambrain crustal evolution; geology and geochemistry of the Archean Craton in Greenland and Labrador; Precambrian crustal evolution in North and South America; and the field excursion to the Ameralik Fjord.

Bed topography of Jakobshavn Isbræ, Greenland from high-resolution gravity data

NASA Astrophysics Data System (ADS)

An, L.; Rignot, E. J.; Morlighem, M.; Paden, J. D.; Holland, D. M.

2015-12-01

Jakobshavn Isbræ (JKS) is one of the largest marine terminating outlet glaciers in Greenland, feeding a fjord about 800 m deep in the west coast. JKS sped up more than twofold since 2002 and contributed nearly 1 mm of global sea level rise during the period from 2000 to 2011. Holland et al. (2008) posit that these changes coincided with a change in ocean conditions beneath the former ice tongue, yet little is known about the depth of the glacier at its grounding line and upstream of the grounding line and the sea floor depth of the fjord is not well known either. Here, we present a new approach to infer the glacier bed topography, ice thickness and sea floor bathymetry near the grounding line of JKS using high-resolution airborne gravity data from AirGRAV. AirGRAV data were collected in August 2012 from a helicopter platform. The data combined with radio echo sounding data, discrete point soundings in the fjord and the mass conservation approach on land ice. AirGRAV acquired a 500m spacing grid of free-air gravity data at 50 knots with sub-milligal accuracy, i.e. much higher than NASA Operation IceBridge (OIB)'s 5.2km resolution at 290 knots. We use a 3D inversion of the gravity data combining our observations and a forward modeling of the surrounding gravity field, and constrained at the boundary by radar echo soundings and point bathymetry. We reconstruct seamless bed topography at the grounding line that matches interior data and the sea floor bathymetry. The results reveal the true depth at the elbow of the terminal valley and the bed reversal in the proximity of the current grounding line. The analysis provides guidelines for future gravity survey of narrow fjords in terms of spatial resolution and gravity precision. The results also demonstrate the practicality of using high resolution gravity survey to resolve bed topography near glacier snouts, in places where radar sounding has been significantly challenged in the past. The inversion results are critical to re-interpret the recent evolution of JKS and reduce uncertainties in projecting its future contribution to sea level. This work was conducted at UCI and at Caltech's Jet Propulsion Laboratory under a contract with the Gordon and Betty More Foundation and with NASA's Cryospheric Science Program.

Ichthyoplankton spatial distribution and its relation with water column stratification in fjords of southern Chile (46°48‧-50°09‧S) in austral spring 1996 and 2008

NASA Astrophysics Data System (ADS)

Bustos, Claudia A.; Landaeta, Mauricio F.; Balbontín, Fernando

2011-03-01

The occidental shore of the southern tip of South America is one of the largest estuarine ecosystems around the world. Although demersal finfish fisheries are currently in full exploitation in the area, the fjords south of 47°S have been poorly investigated. Two bio-oceanographic cruises carried out in austral spring 1996 and 2008 between 47°S and 50°09'S were utilized to investigate the spatial distribution of fish eggs and larvae. Small differences in the environmental conditions were identified in the top 200 m of the water column between years (5.3-10.5 °C and 0.7-33.9 units of salinity in October 1996; 6.3-11.5 °C and 1.2-34.2 units of salinity in November 2008). The low salinity surface layer generated a highly stable water column within the fjords (Brunt-Väisälä frequency, N>0.1 rad/s; wave period <60 s), whereas a well-mixed water column occurred in the gulfs and open channels. For both years, the ichthyoplankton analysis showed that early life stages of lightfish Maurolicus parvipinnis were dominant (>75% total eggs and >70% total larvae) and they were collected throughout the area, irrespective of the water column stratification. However, other components of the ichthyoplankton such as Falkland sprat Sprattus fuegensis, rockfish Sebastes oculatus, and hoki Macruronus magellanicus were more abundant and found in a wider range of larval sizes in less stable waters ( N<0.1 rad/s). Oceanic taxa such as myctophids ( Lampanyctodes hectoris) and gonostomatids ( Cyclothone sp.) were collected exclusively in open waters. The October 1996 observation of Engraulis ringens eggs in plankton samples corresponded to the southernmost record of early stages of this fish in the Pacific Ocean. We found a significant negative relationship between the number of larval species and N, and a significant positive relationship between the number of larval species and wave period. Therefore, only some marine fish species are capable to utilize fjords systems as spawning and nursery grounds in areas having high amounts of freshwater discharges and very high vertical stratification during austral spring season.

Are life histories of Norwegian fjord herring populations of Pacific ancestry similar to those of Atlantic or Pacific herring?

NASA Astrophysics Data System (ADS)

Mikkelsen, Nina; Pedersen, Torstein; dos Santos Schmidt, Thassya Christina; Falk-Petersen, Inger-Britt; Slotte, Aril

2018-04-01

Herring from two unexploited fjord populations, Lake Rossfjord (LRH, n = 100) and Balsfjord (BFH, n = 420) in northern Norway, were sampled in 2014 and 2015. Life history characteristics were analysed and compared to the oceanic Norwegian spring-spawning herring (NSSH), and other Atlantic and Pacific herring stocks. Genetic studies have shown that LRH and BFH are ancestors evolved from Pacific herring that hybridized with Atlantic herring. This study shows that both LRH and BFH mature at a relatively early age, at 2-3 years and ca. 4 years respectively, compared to ca. 5 years for NSSH. The spawning stocks of LRH and BFH consist of small fish and contain relatively few age classes. Both fjord populations have slow growth after sexual maturity; LRH has a very low asymptotic length (L∞ = 19.8 cm), while that of BFH is higher (L∞ of 28.5 cm); both these values being lower than that of NSSH (L∞ of ca. 37 cm). The somatic relative fecundity of LRH is 176.6 oocytes g- 1, while the somatic relative fecundity of recruit and repeat BFH spawners is 152.4 and 183.1 oocytes g- 1, respectively. These estimates are lower than those for NSSH and other Atlantic herring fjord populations, but comparable with other Pacific herring. Due to the smaller body sizes of the spawners in the LRH and BFH populations, absolute fecundity is much lower than in NSSH. The gonadosomatic indices of prespawning fish are similar in LRH and BFH, being slightly higher compared to the NSSH, but lower than values reported for Pacific herring. The natural mortality rates of LRH and BFH (M = 0.64 year- 1 and M = 0.76 year- 1, respectively) are much higher than in NSSH (M = 0.15 year- 1) and most other Atlantic herring populations, except the Lusterfjord herring. However, these high mortality rates are similar to those of several Pacific herring populations. It is concluded that LRH and BFH show low somatic growth and high natural mortality rate. These life history characteristics differ from those of NSSH, but are similar to some Pacific herring populations adapted to a coastal high-mortality risk environment.

The response of nitrifying microbial assemblages to ammonium (NH4+) enrichment from salmon farm activities in a northern Chilean Fjord

NASA Astrophysics Data System (ADS)

Elizondo-Patrone, Claudia; Hernández, Klaudia; Yannicelli, Beatriz; Olsen, Lasse Mork; Molina, Verónica

2015-12-01

The consequences of aquaculture include alterations in nitrogen cycling in aquatic environments that may lead to ecosystem degradation. Herein salmon aquaculture release of ammonium (NH4+) to the water column and its effects on natural archaea and bacteria ammonia-oxidizers (AOA and AOB) and nitrite-oxidizing bacteria (NOB) community structure were studied in the Comau fjord using molecular approaches, such as: cloning (AOA and AOB richness), qPCR for C. Nitrosopumilus maritimus (AOA) and Nitrospina sp. (NOB) abundance (DNA) and RT-qPCR only for Nitrospina sp activity (RNA). Sampling was carried out in brackish (0.7-25 salinity, <5 m depth) and marine (>30 salinity, 25 m depth) waters during contrasting salmon production periods: rest (winter 2012), growth and harvest (summer and winter 2013). During the rest period, the highest NH4+ concentration was observed at Vodudahue River, whereas during productive periods NH4+ accumulated in the brackish layer inside salmon cages and in the vicinty (up to 700 m distance from the cages). The nitrifier community from the fjord reference station (Stn-C) was characterized by C. N. maritimus (AOA) and Nitrosomonas sp. (AOB) sequences affiliated with cosmopolitan ecotypes (e.g., marine, freshwater, hydrothermal), maxima abundances of C. N. maritimus (AOA) and Nitrospina sp. and extreme ranges of Nitrospina sp. activity occurred in the brackish layer. During productive periods, abundances of C. N. maritimus were co-varied with NH4+ concentrations inside salmon cages (summer) and the adjacent areas (winter). Productive periods were characterized by lower abundances but more homogeneity between brackish and marine areas than for the Stn-C nitrifiers. The physiological state of Nitrospina sp. estimated from cDNA:DNA ratios indicated higher growth during winter 2013 associated with NH4+ enrichment derived from production and river input. Our results suggest that in Comau Fjord, NH4+ enrichment events occur during salmon production and also naturally by river inputs, supporting an abundant and active nitrifying community potentially processing only part of the extra NH4+ that occurs, predominantly outside the salmon cages. Our work highlights the abundance and activities of nitrifying communities and identifies these communities as being sensitive to increased loads of NH4+ .

Ocean observations from below Petermann Gletscher

NASA Astrophysics Data System (ADS)

Muenchow, A.; Nicholls, K. W.; Heuzé, C.; Wahlin, A.; Mix, A. C.

2015-12-01

Petermann Gletscher drains 4% of the Greenland ice sheet via a floating ice shelf that has shrunk from 1,300 to 900 km^2 in area via two calving events in 2010 and 2012. The glacier is thinning by about 10 vertical meters per year when integrated over 45 km from the grounding zone to the terminus. Most of this mass loss is caused by ocean melting, but only a single vertical ocean profile taken in 2002 exists. The fjord was mostly free of sea ice in August when we visited in 2003, 2006, 2007, 2009, and 2012 and noticed a small warming trend of bottom waters. During a 2-day survey of Petermann Fjord and adjacent Nares Strait in 2012 we documented a large intrusion of warmer Atlantic waters spilling over the 400 m deep sill and sinking to more than 800 m depth. These waters fill the deep basin of the fjord and move towards the grounding zone of glacier at 550 m below the sea surface. In August 2015 the Swedish icebreaker I/B Oden is scheduled to enter Nares Strait and Petermann Fjord to support field work on land, on water, and on the floating glacier. We here report preliminary results from both ocean surveys and ice shelf moorings. The moored observations from under the ice shelf extend synoptic survey data from Oden. The ice shelf moorings are designed to resolve tidal to interannual variations of water properties under the floating glacier. More specifically, we plan to install a total 13 discrete sensors to measure ocean temperature, salinity, and pressure at five locations distributed both along and across the floating glacier. Hot water drilling provides the holes through the 200 to 500 m thick glacier ice to collect sediment cores, take a profile of temperature and salinity, and deploy two to five cabled sensors per mooring. If successful, data from these cabled instruments will be distributed via surface Iridium connections and posted on the web in near real time. We will discuss successes and failures of this ambitious and high risk program that was facilitated by a bottom-up collaboration of British, Swedish, and US investigators and their respective funding agencies all working on very short and tense schedules. Figure: Sketch of mooring placement on a map (left panel) with 2014 flight tracks and glacier profiles (right panel) obtained from laser altimeter data along the tracks.

Seasonal variability of Dinophysis spp. and Protoceratium reticulatum associated to lipophilic shellfish toxins in a strongly stratified Chilean fjord

NASA Astrophysics Data System (ADS)

Alves-de-Souza, Catharina; Varela, Daniel; Contreras, Cristóbal; de La Iglesia, Pablo; Fernández, Pamela; Hipp, Byron; Hernández, Cristina; Riobó, Pilar; Reguera, Beatriz; Franco, José M.; Diogène, Jorge; García, Carlos; Lagos, Néstor

2014-03-01

The fine scale vertical distribution of Dinophysis spp. and Protoceratium reticulatum (potential producers of lipophilic shellfish toxins, LSTs) and its relation with LSTs in shellfish was studied in Reloncaví fjord, a strongly stratified system in Southern Chile. Samples were taken over two years from late spring to early autumn (2007-2008 period) and from early spring to late summer (2008-2009 period). Dinophysis spp., in particular Dinophysis acuminata, were always detected, often forming thin layers in the region of the salinity driven pycnocline, with cell maxima for D. acuminata of 28.5×103 cells L-1 in March 2008 and 17.1×103 cells L-1 in November 2008. During the 2008-2009 sampling period, blooms of D. acuminata co-occurred with high densities of cryptophyceans and the ciliate Mesodinium spp. The highest levels of pectenotoxin-2 (PTX-2; 2.2 ng L-1) were found in the plankton in February 2009, associated with moderate densities of D. acuminata, Dinophysis tripos and Dinophysis subcircularis (0.1-0.6×103 cells L-1). However, only trace levels of PTX-2 were observed in bivalves at that time. Dinophysistoxin (DTX-1 and DTX-3) levels in bivalves and densities of Dinophysis spp. were not well correlated. Low DTX levels in bivalves observed during a major bloom of D. acuminata in March 2008 suggested that there is a large seasonal intraspecific variability in toxin content of Dinophysis spp. driven by changes in population structure associated with distinct LST toxin profiles in Reloncaví fjord during the study period. A heterogeneous vertical distribution was also observed for P. reticulatum, whose presence was restricted to summer months. A bloom of this species of 2.2×103 cells L-1 at 14 m depth in February 2009 was positively correlated with high concentrations of yessotoxins in bivalves (51-496 ng g-1) and plankton samples (3.2 ng L-1). Our results suggest that a review of monitoring strategies for Dinophysis spp. in strongly stratified fjord systems should be carried out. They also indicate that early warning of LST events based on Dinophysis cell numbers are not reliable for seafood control.

26 CFR 521.103 - Scope of the convention.

Code of Federal Regulations, 2011 CFR

2011-04-01

... CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of... alien who is a resident of Denmark, or by a Danish corporation, from the operation of ships or aircraft registered in Denmark (Article V); (3) Interest and royalties (including motion picture film rentals) derived...

26 CFR 521.103 - Scope of the convention.

Code of Federal Regulations, 2014 CFR

2014-04-01

... CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of... alien who is a resident of Denmark, or by a Danish corporation, from the operation of ships or aircraft registered in Denmark (Article V); (3) Interest and royalties (including motion picture film rentals) derived...

26 CFR 521.103 - Scope of the convention.

Code of Federal Regulations, 2013 CFR

2013-04-01

... CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of... alien who is a resident of Denmark, or by a Danish corporation, from the operation of ships or aircraft registered in Denmark (Article V); (3) Interest and royalties (including motion picture film rentals) derived...

26 CFR 521.103 - Scope of the convention.

Code of Federal Regulations, 2012 CFR

2012-04-01

... CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of... alien who is a resident of Denmark, or by a Danish corporation, from the operation of ships or aircraft registered in Denmark (Article V); (3) Interest and royalties (including motion picture film rentals) derived...

Vocational Education and Training in Denmark. First Edition.

ERIC Educational Resources Information Center

Nielsen, Soren P.

This monograph examines vocational education and training (VT) in Denmark. Section 1 presents background information/framework data on the following: Denmark's political and administrative structure; population, employment, and unemployment; and the Danish economy. In section 2, the history of VT in Denmark is traced from before 1870 to the…

NREL Partners with Technical University of Denmark on Renewable Energy

Science.gov Websites

System | Energy Systems Integration Facility | NREL Technical University of Denmark NREL Partners with Technical University of Denmark on Renewable Energy System NREL is working in partnership with the Technical University of Denmark for the Centre for IT-Intelligent Energy Systems in Cities

Comparison of sick leave patterns between Norway and Denmark in the health and care sector: a register study.

PubMed

Krane, Line; Fleten, Nils; Stapelfeldt, Christina M; Nielsen, Claus Vinther; Jensen, Chris; Johnsen, Roar; Braaten, Tonje

2013-11-01

Sickness absence is of considerable concern in both Norway and Denmark. Labour Force Surveys indicate that absence in Norway is about twice that in Denmark and twice that of the mean reported by the Organisation for Economic Co-operation and Development. This study compares absence patterns according to age, percentage of employment, and occupation between municipal employees in the health and care sectors in two municipalities in Norway and Denmark. Data recorded in the personnel registers of the municipalities of Kristiansand, Norway and Aarhus, Denmark were extracted for the years 2004 and 2008, revealing 3498 and 7751 employee-years, respectively. We calculated absence rates together with number of sick leave episodes, and their association with the above-mentioned covariates. Gender-specific comparative descriptive statistics and negative binomial regression analysis were performed. The sickness absence rate in women was 11.3% in Norway (95% confidence interval [CI] 11.2-11.4) and 7.0% in Denmark (95% CI 7.0-7.1) whereas mean number of sick leave episodes among women was 2.4 in Denmark, compared to 2.3 in Norway (p = 0.02). Young employees in Denmark had more sick leave episodes than in Norway. Proportion of absentees was higher in Denmark compared to Norway (p < 0.0001). The finding of that more employees in Denmark have more frequent, but shorter sick leave episodes compared to Norway, for whatever reasons, may indicate that more frequent sick leaves episodes prevent higher sick leaves rates.

The Role of the Company in Generating Skills. The Learning Effects of Work Organization. Denmark.

ERIC Educational Resources Information Center

Kristensen, Peer Hull; Petersen, James Hopner

The impact of developments in work organizations on the skilling process in Denmark was studied through a macro analysis of available statistical information about the development of workplace training in Denmark and case studies of three Danish firms. The macro analysis focused on the following: Denmark's vocational training system; the Danish…

Variation of phytoplankton assemblages of Kongsfjorden in early autumn 2012: a microscopic and pigment ratio-based assessment.

PubMed

Bhaskar, Jane T; Tripathy, S C; Sabu, P; Laluraj, C M; Rajan, S

2016-04-01

Phytoplankton species distribution and composition were determined by using microscopy and pigment ratios in the Kongsfjorden during early autumn 2012. Variation in sea surface temperature (SST) was minimal and matched well with satellite-derived SST. Nutrients were generally limited. Surface phytoplankton abundance ranged from 0.21 × 10(3) to 10.28 × 10(3) cells L(-1). Phytoplankton abundance decreased with depth and did not show any significant correlation with chlorophyll a (chl a). Column-integrated phytoplankton cell counts (PCC) ranged from 94.3 × 10(6) cells m(-2) (Kf4) to 13.7 × 10(6) cells m(-2) (Kf5), while chl a was lowest at inner part of the fjord (6.3 mg m(-2)) and highest towards the mouth (24.83 mg m(-2)). Biomass from prymnesiophytes and raphidophytes dominated at surface and 10 m, respectively. The contribution of Bacillariophyceae to biomass was low. Generally, heterotrophic dinoflagellates were great in abundance (12.82 %) and ubiquitous in nature and were major contributors to biomass. Various chl pigments (chl b, chl c, phaeopigments (phaeo)) were measured to obtain pigment/chl a ratios to ascertain phytoplankton composition. Phaeo were observed only in inner fjord. Chl b:a ratios and microscopic observations indicated dominance of Chlorophyceae at greater depths than surface. Furthermore, microscopic observations confirmed dominance of chl c containing algae throughout the fjord. The study indicates that pigment ratios can be used as a tool for preliminary identification of major phytoplankton groups. However, under the presence of a large number of heterotrophic dinoflagellates such as Gymnodinium sp. and Gyrodinium sp., pigment signatures need to be supplemented by microscopic observations.

Identifying the optimal depth for mussel suspended culture in shallow and turbid environments

NASA Astrophysics Data System (ADS)

Filgueira, Ramón; Grant, Jon; Petersen, Jens Kjerulf

2018-02-01

Bivalve aquaculture is commonly carried out in shallow water systems, which are susceptible to resuspension of benthic particulate matter by natural processes such as tidal currents, winds and wave action, as well as human activity. The resuspended material can alter the availability of food particles for cultured bivalves. The effect of resuspended material on bivalve bioenergetics and growth is a function of the quality and concentration of resuspended particles and background diet in the water column. Given the potential for positive or negative impacts on bivalve growth and consequently on farm productivity, farmers must position the cultured biomass at the appropriate depth to benefit from or mitigate the impact of this resuspended material. A combination of field measurements, a 1-D vertical resuspension model and a bioenergetic model for mussels based on Dynamic Energy Budget (DEB) theory has been carried out for a mussel farm in Skive Fjord, a shallow Danish fjord, with the aim of identifying the optimal depth for culture. Observations at the farm location revealed that horizontal advection is more important than vertical resuspension during periods with predominant Eastern winds. In addition, high background seston in the water column reduces the impact of resuspension on the available food for mussels. The simulation of different scenarios in terms of food availability suggested minimal effects of resuspension on mussel growth. Based on this finding and the fact that phytoplankton concentration, the main food source for mussels, is usually higher in the upper part of the water column, suspended culture in the top 3 m of the water column seems to be the optimal practice to produce mussels in Skive Fjord.

A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes.

PubMed

Young, Duncan A; Wright, Andrew P; Roberts, Jason L; Warner, Roland C; Young, Neal W; Greenbaum, Jamin S; Schroeder, Dustin M; Holt, John W; Sugden, David E; Blankenship, Donald D; van Ommen, Tas D; Siegert, Martin J

2011-06-02

The first Cenozoic ice sheets initiated in Antarctica from the Gamburtsev Subglacial Mountains and other highlands as a result of rapid global cooling ∼34 million years ago. In the subsequent 20 million years, at a time of declining atmospheric carbon dioxide concentrations and an evolving Antarctic circumpolar current, sedimentary sequence interpretation and numerical modelling suggest that cyclical periods of ice-sheet expansion to the continental margin, followed by retreat to the subglacial highlands, occurred up to thirty times. These fluctuations were paced by orbital changes and were a major influence on global sea levels. Ice-sheet models show that the nature of such oscillations is critically dependent on the pattern and extent of Antarctic topographic lowlands. Here we show that the basal topography of the Aurora Subglacial Basin of East Antarctica, at present overlain by 2-4.5 km of ice, is characterized by a series of well-defined topographic channels within a mountain block landscape. The identification of this fjord landscape, based on new data from ice-penetrating radar, provides an improved understanding of the topography of the Aurora Subglacial Basin and its surroundings, and reveals a complex surface sculpted by a succession of ice-sheet configurations substantially different from today's. At different stages during its fluctuations, the edge of the East Antarctic Ice Sheet lay pinned along the margins of the Aurora Subglacial Basin, the upland boundaries of which are currently above sea level and the deepest parts of which are more than 1 km below sea level. Although the timing of the channel incision remains uncertain, our results suggest that the fjord landscape was carved by at least two iceflow regimes of different scales and directions, each of which would have over-deepened existing topographic depressions, reversing valley floor slopes.

A submarine landslide source for the devastating 1964 Chenega tsunami, southern Alaska

USGS Publications Warehouse

Brothers, Daniel; Haeussler, Peter J.; Lee Liberty,; David Finlayson,; Geist, Eric L.; Labay, Keith A.; Michael Byerly,

2016-01-01

During the 1964 Great Alaska earthquake (Mw 9.2), several fjords, straits, and bays throughout southern Alaska experienced significant tsunami runup of localized, but unexplained origin. Dangerous Passage is a glacimarine fjord in western Prince William Sound, which experienced a tsunami that devastated the village of Chenega where 23 of 75 inhabitants were lost – the highest relative loss of any community during the earthquake. Previous studies suggested the source of the devastating tsunami was either from a local submarine landslide of unknown origin or from coseismic tectonic displacement. Here we present new observations from high-resolution multibeam bathymetry and seismic reflection surveys conducted in the waters adjacent to the village of Chenega. The seabed morphology and substrate architecture reveal a large submarine landslide complex in water depths of 120–360 m. Analysis of bathymetric change between 1957 and 2014 indicates the upper 20–50 m (∼0.7 km3) of glacimarine sediment was destabilized and evacuated from the steep face of a submerged moraine and an adjacent ∼21 km2 perched sedimentary basin. Once mobilized, landslide debris poured over the steep, 130 m-high face of a deeper moraine and then blanketed the terminal basin (∼465 m water depth) in 11 ± 5 m of sediment. These results, combined with inverse tsunami travel-time modeling, suggest that earthquake- triggered submarine landslides generated the tsunami that struck the village of Chenega roughly 4 min after shaking began. Unlike other tsunamigenic landslides observed in and around Prince William Sound in 1964, the failures in Dangerous Passage are not linked to an active submarine delta. The requisite environmental conditions needed to generate large submarine landslides in glacimarine fjords around the world may be more common than previously thought. 

Uranium biogeochemistry across the redox transition zone of a permanently stratified fjord: Framvaren, Norway

USGS Publications Warehouse

Swarzenski, P.W.; McKee, B.A.; Skei, J.M.; Todd, J.F.

1999-01-01

During August 1995, the vertical concentration profile of dissolved and particulate uranium exhibited strong non-conservative characteristics in the upper 30 m of Framvaren Fjord. There was a pronounced peak in both particulate (> 0.2 ??m; 1.09 nM) and dissolved (< 0.2 ??m; 17.06 nM) uranium in the finely stratified waters at the O2/H2S interface which is positioned well within the euphotic zone at about 20-21 m. Such concentration maxima at the redox boundary are also observed for dissolved organic carbon (DEC), Sr and Ba. Dissolved U levels seen in the water column from 18 m down to 30 m exceeded the high salinity (salinity = 35) U concentrations (13.63 ?? 0.84 nM; Chen, J.H., Edwards, R.L., Wasserburg, G.L., 1986. 238U, 234U and 232Th in seawater. Earth Planet Sci. Lett. 80, 241-251.) observed uniformly in the open ocean. A prolific population of S microbes (e.g., Chromatium, Chlorobium sp.) flourishes at the O2/H2S interface. The source of elevated U at the redox boundary must be due to microbial uptake and subsequent release processes rather than dilution from oceanic uranium. Uranium oxidation state determinations in waters from 1, 22 and 30 m depth reveal that reduced U(IV) is not present in significant abundance, and that the chemical and/or biological reduction of hexavalent uranium is largely inhibited. Our results suggest that U and other trace constituents such as DOC, Sr, Ba, Fe(II), Mn(II) are greatly modified by direct and indirect microbial transformation reactions which are most concentrated across the redox transition zone in Framvaren Fjord.

Influence of Glacier Melting and River Discharges on the Nutrient Distribution and DIC Recycling in the Southern Chilean Patagonia

NASA Astrophysics Data System (ADS)

Vargas, Cristian A.; Cuevas, L. Antonio; Silva, Nelson; González, Humberto E.; De Pol-Holz, Ricardo; Narváez, Diego A.

2018-01-01

The Chilean Patagonia constitutes one of the most important and extensive fjord systems worldwide, therefore can be used as a natural laboratory to elucidate the pathway of both organic and inorganic matter in the receiving environment. In this study we use data collected during an intensive oceanographic cruise along the Magellan Strait into the Almirantazgo Fjord in southern Patagonia to evaluate how different sources of dissolved inorganic carbon (DIC) and recycling may impact particulate organic carbon (POC) δ13C and influence the nutrients and carbonate system spatial distribution. The carbonate system presented large spatial heterogeneity. The lowest total alkalinity and DIC were associated to freshwater dilution observed near melting glaciers. The δ13CDIC analysis suggests that most DIC in the upper 50 m depth was not derived from terrestrial organic matter remineralization. 13C-depleted riverine and ice-melting DIC influence the DIC pool along the study area, but due to that DIC concentration from rivers and glaciers is relatively low, atmospheric carbon contribution or biological processes seem to be more relevant. Intense undersaturation of CO2 was observed in high chlorophyll waters. Respired DIC coming from the bottom waters seems to be almost insignificant for the inorganic carbon pool and therefore do not impact significantly the stable carbon isotopic composition of dissolved organic carbon and POC in the upper 50 m depth. Considering the combined effect of cold and low alkalinity waters due to ice melting, our results highlight the importance of these processes in determining corrosive waters for CaCO3 and local acidification processes associated to calving glacier in fjord ecosystems.

Physiological characteristics of wild Atlantic salmon post-smolts during estuarine and coastal migration

USGS Publications Warehouse

Stefansson, S.O.; Bjornsson, B. Th; Sundell, K.; Nyhammer, G.; McCormick, S.D.

2003-01-01

Changes were measured in some of the major physiological variables associated with seawater adaptability, growth and energetics in wild Atlantic salmon Salmo salar smolts and post-smolts migrating from the river and through the estuary, fjord and coastal areas in the River Orkla and the Trondheimsfjord, Norway during late May to early June. Gill Na+,K+-ATPase activity increased to levels of 12-16 ??mol ADP mg protein-1 h -1 in post-smolts caught in higher salinity zones, probably representing long-term levels of Atlantic salmon post-smolts in oceanic conditions. Muscle moisture was regulated within narrow limits (77.7-78.7%) in fish from all zones during both years, suggesting that post-smolts adapt to marine conditions without any long-term disturbance of hydro-mineral balance. Lipid and glycogen content showed a general trend towards depletion from the river, through the fjord and into the ocean. There was, however, no significant change in protein content. The present results confirm that smolts are naturally 'energy deficient' during downstream migration, and suggest that post-smolts also mobilize energy reserves during their early marine phase, while protein is allocated for somatic growth. Plasma growth hormone (GH) levels increased transiently during passage through the estuary and fjord, with lower levels observed in post-smolts caught off-shore, i.e. in fish which were feeding on marine prey and had adapted to the marine environment. These physiological changes may confer substantial selective advantages during the critical early marine phase of anadromous salmonids, and hence are adaptive for long-term survival in sea water. ?? 2003 The Fisheries Society of the British Isles.

Laboratory Experiments Investigating Glacier Submarine Melt Rates and Circulation in an East Greenland Fjord

NASA Astrophysics Data System (ADS)

Cenedese, C.

2014-12-01

Idealized laboratory experiments investigate the glacier-ocean boundary dynamics near a vertical 'glacier' (i.e. no floating ice tongue) in a two-layer stratified fluid, similar to Sermilik Fjord where Helheim Glacier terminates. In summer, the discharge of surface runoff at the base of the glacier (subglacial discharge) intensifies the circulation near the glacier and increases the melt rate with respect to that in winter. In the laboratory, the effect of subglacial discharge is simulated by introducing fresh water at melting temperatures from either point or line sources at the base of an ice block representing the glacier. The circulation pattern observed both with and without subglacial discharge resembles those observed in previous studies. The buoyant plume of cold meltwater and subglacial discharge water entrains ambient water and rises vertically until it finds either the interface between the two layers or the free surface. The results suggest that the meltwater deposits within the interior of the water column and not entirely at the free surface, as confirmed by field observations. The submarine melt rate increases with the subglacial discharge rate. Furthermore, the same subglacial discharge causes greater submarine melting if it exits from a point source rather than from a line source. When the subglacial discharge exits from two point sources, two buoyant plumes are formed which rise vertically and interact. The results suggest that the distance between the two subglacial discharges influences the entrainment in the plumes and consequently the amount of submarine melting and the final location of the meltwater within the water column. Hence, the distribution and number of sources of subglacial discharge may play an important role in glacial melt rates and fjord stratification and circulation. Support was given by NSF project OCE-113008.

EDITORIAL: The 24th Nordic Semiconductor Meeting The 24th Nordic Semiconductor Meeting

NASA Astrophysics Data System (ADS)

Páll Gunnlaugsson, Haraldur; Nylandsted Larsen, Arne; Uhrenfeldt, Christian

2012-03-01

A Nordic Semiconductor Meeting is held every other year with the venue rotating amongst the Nordic countries of Denmark, Finland, Iceland, Norway and Sweden. The focus of these meetings remains 'original research and science being carried out on semiconductor materials, devices and systems'. Reports on industrial activity have usually featured. The topics have ranged from fundamental research on point defects in a semiconductor to system architecture of semiconductor electronic devices. Proceedings from these events are regularly published as a Topical Issue of Physica Scripta. All of the papers in this Topical Issue have undergone critical peer review and we wish to thank the reviewers and the authors for their cooperation, which has been instrumental in meeting the high scientific standards and quality of the series. This 24th meeting of the Nordic Semiconductor community, NSM 2011, was held at Fuglsøcentret, close to Aarhus, Denmark, 19-22 June 2011. Support was provided by the Carlsberg Foundation, Danfysik and the semiconductor group at Aarhus University. Over 30 participants presented a broad range of topics covering semiconductor materials and devices as well as related material science interests. The conference provided a forum for Nordic and international scientists to present and discuss new results and ideas concerning the fundamentals and applications of semiconductor materials. The aim of the meeting was to advance the progress of Nordic science and thus aid in future worldwide technological advances concerning technology, education, energy and the environment. The 25th Nordic Semiconductor Meeting will be organized in June 2013 in Finland, chaired by Dr Filip Tuomisto, Aalto University. A Nordic Summer School on Semiconductor Science will be organized in connection with the conference (just before), chaired by Dr Jonatan Slotte, Aalto University. Information on these events can be found at physics.aalto.fi/nsm2013. List of participants Søren Vejling AndersenAalborg University, Aalborg, Denmark Pia BomholtAarhus University, Aarhus, Denmark Hafliði P GíslasonUniversity of Iceland, Reykjavik, Iceland Haraldur Páll GunnlaugssonAarhus University, Aarhus, Denmark John HansenAarhus University, Aarhus, Denmark Britta JohansenAarhus University, Aarhus, Denmark Volodymyr KhranovskyyLinköping University, Linköping, Sweden Arne Nylandsted LarsenAarhus University, Denmark Helge MalmbekkUniversity of Oslo, Oslo, Norway Erik Stensrud MarsteinInstitute for Energy Technology, Kjeller, Norway Antonio MartiUniversidad Politécnica de Madrid, Madrid, Spain Torben MølholtUniversity of Iceland, Reykjavik, Iceland Sveinn ÓlafssonUniversity of Iceland, Reykjavik, Iceland Thomas PedersenTechnical University of Denmark, Kgs. Lyngby, Denmark Thomas Garm PedersenAalborg University, Aalborg, Denmark Dirch Hjorth PetersenTechnical University of Denmark, Kgs. Lyngby, Denmark Vincent QuemenerUniversity of Oslo, Oslo, Norway Henry RadamsonKTH Royal Institute of Technology, Kista, Sweden Bahman RaeissiUniversity of Oslo, Oslo, Norway Jonatan SlotteAalto University, Aalto, Finland Xin SongUniversity of Oslo, Oslo, Norway Einar Örn SveinbjörnssonUniversity of Iceland, Reykjavik, Iceland Mikael SyväjärviLinköping University, Linköping, Sweden Chi Kwong TangUniversity of Oslo, Oslo, Norway Erik V ThomsenTechnical University of Denmark, Kgs. Lyngby, Denmark Christian UhrenfeldtAarhus University, Aarhus, Denmark Hans Ulrik UlriksenAalborg University, Aalborg, Denmark Muhammad UsmanKTH Royal Institute of Technology, Kista, Sweden Lasse VinesUniversity of Oslo, Oslo, Norway Ulrich WahlUnidade de Física e Aceleradores, Sacavém, Portugal Helge WemanNTNU, Trondheim, Norway Gerd WeyerAarhus University, Denmark

Contrasting controls of pH climatology in an open coast versus urban fjord estuary

EPA Science Inventory

Interactions of physical, chemical, and biological processes in the coastal zone can result in a highly variable carbonate chemistry regime. This characteristic variability in coastal areas has garnered renewed interest within the context of ocean acidification, yet the relative...

36 CFR 13.1324 - Bicycles.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Bicycles. 13.1324 Section 13.1324 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed Area...

36 CFR 13.1326 - Snowmachines.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Snowmachines. 13.1326 Section 13.1326 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

36 CFR 13.1320 - Camping.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Camping. 13.1320 Section 13.1320 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed Area...

Biological effects of long term fine limestone tailings discharge in a fjord ecosystem.

PubMed

Brooks, Lucy; Melsom, Fredrik; Glette, Tormod

2015-07-15

Benthic infaunal data collected from 1993 to 2010 were analysed to examine the effect of long term discharge of fine limestone tailings on macrofaunal species assemblages in a fjord. Relative distance from the outfall and proportion of fine tailings in the sediment were correlated with benthic community structure. Diversity decreased with increasing proportion of fine tailings. Biological Traits Analysis (BTA) was used to explore the temporal and spatial effects of the tailings gradient on macrofaunal functional attributes. BTA revealed that all stations along a pressure gradient of fine limestone tailings were dominated by free-living species. As the proportion of fine tailings in the sediment increased, there was an increase in fauna that were smaller, highly mobile, living on or nearer the surface sediment, with shorter lifespans. There was a decrease in permanent tube dwellers, those fauna with low or no mobility, that live deeper in the sediment and have longer lifespans (>5 yrs). Copyright © 2015 Elsevier Ltd. All rights reserved.

Metal concentrations, sperm motility, and RNA/DNA ratio in two echinoderm species from a highly contaminated fjord (the Sørfjord, Norway).

PubMed

Catarino, Ana I; Cabral, Henrique N; Peeters, Kris; Pernet, Philippe; Punjabi, Usha; Dubois, Philippe

2008-07-01

The present study evaluated the effects of field metal contamination on sperm motility and the RNA/DNA ratio in echinoderms. Populations of Asterias rubens and Echinus acutus that occur naturally along a contamination gradient of sediments by cadmium, copper, lead, and zinc in a Norwegian fjord (the Sørfjord) were studied. Sperm motility, a measure of sperm quality, was quantified using a computer-assisted sperm analysis system. The RNA/DNA ratio, a measure of protein synthesis, was assessed by a one-dye (ethidium bromide)/one-enzyme (RNase), 96-well microplate fluorometric assay. Although both species accumulate metals at high concentrations, neither sperm motility parameters in A. rubens nor the RNA/DNA ratio in both species were affected. The Sørfjord is still one of the most metal-contaminated marine sites in Europe, but even so, populations of A. rubens and E. acutus are able to endure under these conditions.

Vulnerability of Southeast Greenland Glaciers to Warm Atlantic Water From Operation IceBridge and Ocean Melting Greenland Data

NASA Astrophysics Data System (ADS)

Millan, R.; Rignot, E.; Mouginot, J.; Wood, M.; Bjørk, A. A.; Morlighem, M.

2018-03-01

We employ National Aeronautics and Space Administration (NASA)'s Operation IceBridge high-resolution airborne gravity from 2016, NASA's Ocean Melting Greenland bathymetry from 2015, ice thickness from Operation IceBridge from 2010 to 2015, and BedMachine v3 to analyze 20 major southeast Greenland glaciers. The results reveal glacial fjords several hundreds of meters deeper than previously thought; the full extent of the marine-based portions of the glaciers; deep troughs enabling warm, salty Atlantic Water (AW) to reach the glacier fronts and melt them from below; and few shallow sills that limit the access of AW. The new oceanographic and topographic data help to fully resolve the complex pattern of historical ice front positions from the 1930s to 2017: glaciers exposed to AW and resting on retrograde beds have retreated rapidly, while glaciers perched on shallow sills or standing in colder waters or with major sills in the fjords have remained stable.

Reassessment of seismically induced, tsunamigenic submarine slope failures in Port Valdez, Alaska, USA

USGS Publications Warehouse

Lee, H.J.; Haeussler, P.J.; Kayen, R.E.; Hampton, M.A.; Locat, Jacques; Suleimani, E.; Alexander, C.R.

2007-01-01

The M9.2 Alaska earthquake of 1964 caused major damage to the port facilities and town of Valdez, most of it the result of submarine landslide and the consequent tsunamis. Recent bathymetric multibeam surveys, high-resolution subbottom profiles, and dated sediment cores in Port Valdez supply new information about the morphology and character of the landslide deposits. A comparison of pre- and post-earthquake bathymetry provides an estimate of the net volume of landslide debris deposited in the basin and the volume of sediment removed from the source region. Landslide features include (1) large blocks (up to 40-m high) near the location of the greatest tsunamiwave runup (~50 m), (2) two debris lobes associated with the blocks, (3) a series of gullies, channels and talus, near the fjord-head delta and badly damaged old town of Valdez, and (4) the front of a debris lobe that flowed half-way down the fjord from the east end.

Towards quantifying the glacial runoff signal in the freshwater input to Tyrolerfjord-Young Sound, NE Greenland.

PubMed

Citterio, Michele; Sejr, Mikael K; Langen, Peter L; Mottram, Ruth H; Abermann, Jakob; Hillerup Larsen, Signe; Skov, Kirstine; Lund, Magnus

2017-02-01

Terrestrial freshwater runoff strongly influences physical and biogeochemical processes at the fjord scale and can have global impacts when considered at the Greenland scale. We investigate the performance of the HIRHAM5 regional climate model over the catchments delivering freshwater to Tyrolerfjord and Young Sound by comparing to the unique Greenland Ecological Monitoring database of in situ observations from this region. Based on these findings, we estimate and discuss the fraction of runoff originating from glacierized and non-glacierized land delivered at the daily scale between 1996 and 2008. We find that glaciers contributed on average 50-80% of annual terrestrial runoff when considering different sections of Tyrolerfjord-Young Sound, but snowpack depletion on land and consequently runoff happens about one month earlier in the model than observed in the field. The temporal shift in the model is a likely explanation why summer surface salinity in the inner fjord did not correlate to modelled runoff.

Egg buoyancy variability in local populations of Atlantic cod (Gadus morhua).

PubMed

Jung, Kyung-Mi; Folkvord, Arild; Kjesbu, Olav Sigurd; Agnalt, Ann Lisbeth; Thorsen, Anders; Sundby, Svein

2012-01-01

Previous studies have found strong evidences for Atlantic cod ( Gadus morhua ) egg retention in fjords, which are caused by the combination of vertical salinity structure, estuarine circulation, and egg specific gravity, supporting small-scaled geographical differentiations of local populations. Here, we assess the variability in egg specific gravity for selected local populations of this species, that is, two fjord-spawning populations and one coastal-spawning population from Northern Norway (66-71°N/10-25°E). Eggs were naturally spawned by raised broodstocks (March to April 2009), and egg specific gravity was measured by a density-gradient column. The phenotype of egg specific gravity was similar among the three local populations. However, the associated variability was greater at the individual level than at the population level. The noted gradual decrease in specific gravity from gastrulation to hatching with an increase just before hatching could be a generic pattern in pelagic marine fish eggs. This study provides needed input to adequately understand and model fish egg dispersal.

Effect of oxygen minimum zone formation on communities of marine protists

PubMed Central

Orsi, William; Song, Young C; Hallam, Steven; Edgcomb, Virginia

2012-01-01

Changes in ocean temperature and circulation patterns compounded by human activities are leading to oxygen minimum zone (OMZ) expansion with concomitant alteration in nutrient and climate active trace gas cycling. Here, we report the response of microbial eukaryote populations to seasonal changes in water column oxygen-deficiency using Saanich Inlet, a seasonally anoxic fjord on the coast of Vancouver Island British Columbia, as a model ecosystem. We combine small subunit ribosomal RNA gene sequencing approaches with multivariate statistical methods to reveal shifts in operational taxonomic units during successive stages of seasonal stratification and renewal. A meta-analysis is used to identify common and unique patterns of community composition between Saanich Inlet and the anoxic/sulfidic Cariaco Basin (Venezuela) and Framvaren Fjord (Norway) to show shared and unique responses of microbial eukaryotes to oxygen and sulfide in these three environments. Our analyses also reveal temporal fluctuations in rare populations of microbial eukaryotes, particularly anaerobic ciliates, that may be of significant importance to the biogeochemical cycling of methane in OMZs. PMID:22402396

Multifrequency acoustic observations of zooplankton in Knight Inlet, B.C

NASA Astrophysics Data System (ADS)

Trevorrow, Mark V.; Mackas, David L.; Benfield, Mark C.

2004-05-01

A collaborative investigation of midwater zooplankton aggregations in a coastal fjord was conducted in November 2002. Midwater aggregations of zooplankton in a coastal fjord were sampled and mapped using a calibrated, three-frequency (38, 120, and 200 kHz) vessel-based echo-sounder system, a multinet towed zooplankton net (BIONESS), and a high-resolution in situ camera system (ZOOVIS). Dense daytime layers of euphausiids and amphipods near 70- to 90-m depth were found in the lower reaches of the inlet, especially concentrated by tidal flows around a sill which rises above the layer. Quantitative euphausiid and amphipod backscattering measurements, combined with in situ species, size, and abundance estimates, were found to agree closely with recent size- and orientation-averaged fluid-cylinder scattering models produced by Stanton et al. Also, in situ scattering measurements of physonect siphonophores were found to have a much stronger low-frequency (38 kHz) scattering strength, in agreement with a simple bubble scattering model. [Work supported by Dr. J. Eckman, ONR code 322BC.

Towards 50% wind electricity in Denmark: Dilemmas and challenges

NASA Astrophysics Data System (ADS)

Bach, Paul-Frederik

2016-05-01

Electricity and heat supply systems are essential contributors to a fossil-free future in Denmark. The combined production of heat and power (CHP) and the production of wind energy are already well developed in Denmark. Combined heat and power covers about 40% of the demand for space heating in Denmark, and the production of wind energy is supposed to exceed 50% of the demand for electricity by 2020. The changing electricity and heat production has some consequences already now: i) Decreasing wholesale prices in Denmark and in other countries. ii) Thermal power plants are closing down. Denmark is no longer self-sufficient with electricity under all conditions. iii) The electricity production pattern does not match the demand pattern. The result is that the neighbouring countries must absorb the variations from wind and solar power. Essential challenges: i) The future of combined heat and power in Denmark is uncertain. ii) Denmark will need new backup capacity for filling the gaps in wind power and solar cell output. iii) Flexible electricity consumers are supposed to contribute to balancing the future power systems. There is still a long way to go before the Smart Grid visions are implemented in large scale. iv) The transformation of the power system will create new risks of power failures.

36 CFR 13.1308 - Harding Icefield Trail.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Harding Icefield Trail. 13.1308 Section 13.1308 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General...

36 CFR 13.1310 - Pets.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Pets. 13.1310 Section 13.1310 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions § 13.1310 Pets...

Slope Stability Analysis and Event Reconstruction of the Karrat Fjord (W Greenland) Rock Avalanche from June 2017 using Sentinel-1 and Sentinel-2 data

NASA Astrophysics Data System (ADS)

Langley, K.; Caduff, R.; Wiesmann, A.; Mätzler, E.

2017-12-01

A massive rock slope failure that led to a rock avalanche in the Karrat Fjord, Western Greenland, caused a tsunami on 17 June 2017. The tsunami reached local villages and resulted in loss of life and damage to infrastructure. The length of the rock avalanche detachment zone is on the order of 800 m. It is located at an elevation of 1'000 m above the fjord with a slant distance of 2'000 m to the shore line. Since very little information was available on the state of the originating mountain slope, satellite based information was gathered immediately after the event in order to assess the processes on the slope. Thanks to the quick data distribution through Copernicus, we could process the entire available datasets of the Synthetic Aperture Radar (SAR) sensors Sentinel-1A/B and the optical sensor Sentinel-2. The pre-, syn, and post-event history could be reconstructed using ascending orbit Sentinel-1 data, available from October 2014 in 12 and from early 2017 on in 6d interval. We looked at the differential interferograms to detect coherent surface displacements in line-of-sight (LOS). Coherent interferograms after the snow-melt in May 2017 revealed surface displacements of 10-15 cm/year with accelerating trend in the later detachment zone. The known limitation for interferometry in wet-snow condition hinders the determination of areas undergoing surface deformation. However, a detailed coherence analysis showed that during the previous winter, a large avalanche type process must have happened in the later detachment zone. A radar backscatter analysis showed, that significant changes in the corridor of 500 m of the area affected by the rock avalanche can be dated between 5 and 11 November 2016. The traces of the event could be verified with optical imagery from Sentinel-2 dating from 23 May 2017. An overall analysis on the mountain side revealed the presence of a number of active zones. An inventory of the outlines of the moving areas containing information on the LOS surface velocities was created, helping to assess possible accelerated or new slope instability appearances in the ongoing analysis of Sentinel-1 acquisitions. We present the methodology, the results and conclude with a discussion on the future impact of the analysis and the experience of the Karrat Fjord event for future hazard monitoring using Sentinel-1/2 data.

Late-glacial to Holocene environmental changes and climate variability: evidence from Voldafjorden, western Norway

NASA Astrophysics Data System (ADS)

Sejrup, H. P.; Haflidason, H.; Flatebø, T.; Klitgaard Kristensen, D.; Grøsfjeld, K.; Larsen, E.

2001-02-01

Sedimentological, micropalaeontological (benthic foraminifers and dinoflagellate cysts), stable isotope data and AMS 14C datings on cores and surface samples, in addition to acoustic data, have been obtained from Voldafjorden, western Norway. Based on these data the late glacial and Holocene sedimentological processes and variability in circulation and fjord environments are outlined. Glacial marine sedimentation prevailed in the Voldafjorden between 11.0 kyr and 9.2 kyr BP (radiocarbon years). In the later part of the Allerød period, and for the rest of the Holocene, there was deposition of fine-grained normal marine sediments in the fjord basin. Turbidite layers, recorded in core material and on acoustic profiles, dated to ca. 2.1, 6.9-7.6, ca. 9.6 and ca. 11.0 kyr BP, interrupted the marine sedimentation. The event dated to between 6.9 and 7.6 kyr BP probably corresponds to a tsunami resulting from large-scale sliding on the continental margin off Norway (the Storegga Tsunami).During the later part of the Allerød period, Voldafjorden had a strongly stratified water column with cold bottom water and warm surface water, reaching interglacial temperatures during the summer seasons. During the Younger Dryas cold event there was a return to arctic sea-surface summer temperatures, possibly with year-round sea-ice cover, the entire benthic fauna being composed of arctic species. The first strong Holocene warming, observed simultaneously in bottom and sea-surface temperature proxies, occurred at ca. 10.1 kyr BP. Bottom water proxies indicate two cold periods, possibly with 2°C lowering of temperatures, at ca. 10.0 (PBO 1) and at 9.8 kyr BP (PBO 2). These events may both result from catastrophic outbursts of Baltic glacial lake water. The remainder of the Holocene experienced variability in basin water temperature, indicated by oxygen isotope measurements with an amplitude of ca. 2°C, with cooler periods at ca. 8.4-9.0, 5.6, 5.2, 4.6, 4.2, 3.5, 2.2, 1.2 and 0.4-0.8 kyr BP. Changes in the fjord hydrology through the past 11.3 kyr show a close correspondence, both in amplitude and timing of events, recorded in cores from the Norwegian Sea region and the North Atlantic. These data suggest a close relationship between fjord environments and variability in large-scale oceanic circulation.

Benthic food web structure in the Comau fjord, Chile (∼42°S): Preliminary assessment including a site with chemosynthetic activity

NASA Astrophysics Data System (ADS)

Zapata-Hernández, Germán; Sellanes, Javier; Mayr, Christoph; Muñoz, Práxedes

2014-12-01

Using C and N stable isotopes we analyzed different trophic aspects of the benthic fauna at two sites in the Comau fjord: one with presence of venting of chemically reducing fluids and extensive patches of bacterial mats (XH: X-Huinay), and one control site (PG: Punta Gruesa) with a typical fjord benthic habitat. Due to the widespread presence of such microbial patches in the fjord and their recognized trophic role in reducing environments, we hypothesize that these microbial communities could be contributing to the assimilated food of consumers and transferring carbon into high trophic levels in the food web. Food sources in the area included macroalgae with a wide range of δ13C values (-34.7 to -11.9‰), particulate organic matter (POM, δ13C = -20.1‰), terrestrial organic matter (TOM, δ13C = -32.3‰ to -27.9‰) and chemosynthetic filamentous bacteria (δ13C = ∼-33‰). At both sites, fauna depicted typical values indicating photosynthetic production as a main food source (>-20‰). However, at XH selected taxa reported lower δ13C values (e.g. -26.5‰ in Nacella deaurata), suggesting a partial use of chemosynthetic production. Furthermore, enhanced variability at this site in δ13C values of the polyplacophoran Chiton magnificus, the limpet Fissurella picta and the tanaid Zeuxoides sp. may also be responding to the use of a wider scope of primary food sources. Trophic position estimates suggest three trophic levels of consumers at both sites. However, low δ15N values in some grazer and suspension-feeder species suggest that these taxa could be using other sources still to be identified (e.g. bacterial films, microalgae and organic particles of small size-fractions). Furthermore, between-site comparisons of isotopic niche width measurements in some trophic guilds indicate that grazers from XH have more heterogenic trophic niches than at PG (measured as mean distance to centroid and standard deviation of nearest neighbor distance). This last could be ascribed to the utilization of a mixture of photosynthetic and chemosynthetic carbon sources. In addition, corrected standard ellipses area (SEAc) values in suspension-feeders and carnivores at both sites suggest a similar magnitude of exploitation of food sources. However, grazers from XH have a greater expansion of their isotopic niche (SEAc), probably explained by the presence of species with low δ13C and δ15N values, and directly associated to chemosynthetic carbon incorporation.

Denmark. A Study of the Educational System of Denmark and Guide to the Academic Placement of Students in Educational Institutions in the United States. PIER World Education Series.

ERIC Educational Resources Information Center

Woolston, Valerie A.; Dickey, Karlene N.

This volume offers a full country study of the structure and content of the educational system of Denmark, together with a formal set of placement recommendations for Danish students wishing to study in the United States. Chapter 1 introduces the volume with descriptions of Denmark and its people, government, the government's role in education,…

36 CFR 13.1310 - Pets.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Pets. 13.1310 Section 13.1310... SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions § 13.1310 Pets. (a) Pets are prohibited— (1) In the Exit Glacier Developed Area except in the parking lot, on the...

36 CFR 13.1310 - Pets.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Pets. 13.1310 Section 13.1310... SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions § 13.1310 Pets. (a) Pets are prohibited— (1) In the Exit Glacier Developed Area except in the parking lot, on the...

36 CFR 13.1310 - Pets.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Pets. 13.1310 Section 13.1310... SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions § 13.1310 Pets. (a) Pets are prohibited— (1) In the Exit Glacier Developed Area except in the parking lot, on the...

36 CFR 13.1312 - Climbing and walking on Exit Glacier.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Climbing and walking on Exit Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park...

36 CFR 13.1306 - Public use cabins.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Public use cabins. 13.1306 Section 13.1306 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions § 13...

36 CFR 13.1318 - Location of the EGDA.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Location of the EGDA. 13.1318 Section 13.1318 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

36 CFR 13.1316 - Commercial transport of passengers by motor vehicles.

Code of Federal Regulations, 2012 CFR

2012-07-01

... passengers by motor vehicles. 13.1316 Section 13.1316 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions § 13.1316 Commercial transport of passengers by motor vehicles. Commercial...

36 CFR 13.1328 - EGDA closures and restrictions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false EGDA closures and restrictions. 13.1328 Section 13.1328 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit...

36 CFR 13.1304 - Ice fall hazard zones.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Ice fall hazard zones. 13.1304 Section 13.1304 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General...

36 CFR 13.1318 - Location of the EGDA.

Code of Federal Regulations, 2013 CFR

2013-07-01

... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed... boundary to Exit Glacier Campground Entrance Road, all park areas within 350 meters (383 yards) of the centerline of the Exit Glacier Road; (2) From Exit Glacier Campground Entrance Road to the end of the main...

36 CFR 13.1318 - Location of the EGDA.

Code of Federal Regulations, 2011 CFR

2011-07-01

... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed... boundary to Exit Glacier Campground Entrance Road, all park areas within 350 meters (383 yards) of the centerline of the Exit Glacier Road; (2) From Exit Glacier Campground Entrance Road to the end of the main...

36 CFR 13.1318 - Location of the EGDA.

Code of Federal Regulations, 2014 CFR

2014-07-01

... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed... boundary to Exit Glacier Campground Entrance Road, all park areas within 350 meters (383 yards) of the centerline of the Exit Glacier Road; (2) From Exit Glacier Campground Entrance Road to the end of the main...

Implementation and validation of a current model system in the greatest sound in the North East Atlantic archipelago of the Faroe Islands

NASA Astrophysics Data System (ADS)

Vagsheyg Erenbjerg, Sissal; Albretsen, Jon; Asplin, Lars; Joensen, Erna; Sandvik, Anne; Simonsen, Knud; Kaas, Eigil

2017-04-01

The location of the Faroe Islands on the Greenland-Scotland ridge puts the oceanography on the boundary of deep water and shelf and fjord dynamics. This placement in close proximity of the deep ocean currents, important for heat transport towards the Arctic, makes the Faroe Islands higly exposed to climate change. Therefore it is important to understand the interaction of deep water oceanography and fjord dynamics in general, to be able to predict potential impact, due to changes in ocean parameters. The Faroe Islands consist of 18 islands. The topographic characteristics are typical for an ice sheet shaped land surface with long and slim islands, steep mountain sides divided by narrow and relatively deep fjords. This highly complex topography is greatly influenced by wind conditions. Sundalagið separates the two largest islands: Streymoy and Eysturoy and has three fjordarms and two main basins. The northern part (SUN) is 15km long and 100m-1.6km wide. The sound is bound to the north by a 9m deep sill. Towards the south by a narrowing of a 100 meter wide and around four meter deep sill, depending on tidal conditions. The southern part (SUS) is not as clearly constricted but contains three major basins with depths ranging from 70-100m (Hansen et al., 1990). We have implemented a nested model system using high resolution bathymetry in the fjords and the entire shelf as well as the open-source hydrodynamical model ROMS (Regional Ocean Modeling System, http://myroms.org). The Faroe Islands model applications are using triply, one way nested grids with 800 → 160 → 32 meter resolutions in the horizontal. This gives us the opportunity to both simulate the deep water oceanography applying 800m resolution as well as the dynamics in the shallow regions using finer resolution models. A particular interest in the area is the influence of the tidal regime. In SUN the tidal dynamics are quite limited due to the location of an amphidromeice point in the Nolsoy fjord (M2=10.4cm (www.dmi.dk)) whereas SUN is heavily dominated by tidal dynamics (M2=63.1cm). The general observation is a more pronounced stratification in SUN and higher vertical mixing in the water column in SUS (2016 CTD mesurements). Our ROMS simulations are run for the year 2013 (only part of the year for the 32m resolution) and forced with high-resolution atmospheric conditions (WRF-1km), large-scale ocean fields (ROMS 4km) of currents, hydrography and sea level (Lien et al., 2014), global tides (TPXO7.2) and climatological freshwater discharges including the main rivers. In this study we validate the model simulations using in-situ data coverage (ACDP) in the local area. A well-functioning dynamical model system is highly important for the Faroe Islands where aquaculture is by far the greatest industry. Linking this to a particle tracking module will further increase the understanding of climate impact in the Faroes in particular with regards to the changes for the biological cycle and mitigation of sea lice (a challenging parasite for the aquaculture) by temperature changes.

Rates and characteristics of sleep paralysis in the general population of Denmark and Egypt.

PubMed

Jalal, Baland; Hinton, Devon E

2013-09-01

In the current research we report data from two studies that examined rates and characteristics of sleep paralysis (SP) in the general population of Denmark and Egypt. In Study I, individuals from Denmark and Egypt did not differ in age whereas there were more males in the Egyptian sample (47 vs. 64 %); in Study II, individuals from Denmark and Egypt were comparable in terms of age and gender distribution. In Study I we found that significantly fewer individuals had experienced SP in Denmark [25 % (56/223)] than in Egypt [44 % (207/470)] p < .001. In Study II we found that individuals who had experienced at least one lifetime episode of SP from Denmark (n = 58) as compared to those from Egypt (n = 143) reported significantly fewer SP episodes in a lifetime relative to SP experiencers from Egypt (M = 6.0 vs. M = 19.4, p < .001). SP in the Egyptian sample was characterized by high rates of SP (as compared to in Denmark), frequent occurrences (three times that in the Denmark sample), prolonged immobility during SP, and great fear of dying from the experience. In addition, in Egypt, believing SP to be precipitated by the supernatural was associated with fear of the experience and longer SP immobility. Findings are discussed in the context of cultural elaboration and salience theories of SP.

Income-related and educational inequality in small-for-gestational age and preterm birth in Denmark and Finland 1987-2003.

PubMed

Mortensen, Laust H; Lauridsen, Jørgen T; Diderichsen, Finn; Kaplan, George A; Gissler, Mika; Andersen, Anne-Marie N

2010-02-01

In this paper, we examine income- and education-related inequality in small-for-gestational age (SGA) and preterm birth in Denmark and Finland from 1987 to 2003 using concentration indexes (CIXs). From the national medical birth registries we gathered information on all births from 1987 to 2003. Information on highest completed maternal education and household income in the year preceding birth of the offspring was obtained for 1,012,400 births in Denmark and 499,390 in Finland. We then calculated CIXs for income- and education-related inequality in SGA and preterm birth. The mean household income-related inequality in SGA was -0.04 (95% confidence interval: -0.05, -0.04) in Denmark and -0.03 (-0.04, -0.02) in Finland. The maternal education-related inequality in SGA was -0.08 (-0.10, -0.06) in Denmark and -0.07 (-0.08, -0.06) in Finland. The income-related inequality in preterm birth was -0.03 (-0.03, -0.02) in Denmark and -0.03 (-0.04, -0.02) in Finland. The education-related inequality in preterm birth was -0.05 (-0.07, -0.04) in Denmark and -0.04 (-0.05, -0.03) in Finland. In Denmark, the income-related and education-related inequity in SGA increased over time. In Finland, the income-related inequality in SGA birth increased slightly, while education-related inequalities remained stable. Inequalities in preterm birth decreased over time in both countries. Denmark and Finland are examples of nations with free prenatal care and publicly financed obstetric care of high quality. During the period of study there were macroeconomic shocks affecting both countries. However, only small income- and education-related inequalities in SGA and preterm births during the period were observed.

Concentrating Solar Power Projects in Denmark | Concentrating Solar Power |

Science.gov Websites

;alphabetical by project name. You can browse a project profile by clicking on the project name. Aalborg CSP-Brà NREL Denmark Concentrating solar power (CSP) projects in Denmark are listed belowâ€"

Measuring the Thermal Conductivity of Sediments for the Estimation of Groundwater Discharge to Surface Waters with Temperature Probes

NASA Astrophysics Data System (ADS)

Duque, C.; Müller, S.; Sebok, E.; Engesgaard, P. K.

2015-12-01

Using temperature probes is a common exploratory method for studying groundwater-surface water interaction due to the ease for collecting measurements and the simplicity of the different analytical solutions. This approach requires to define the surface water temperature, the groundwater temperature and a set of parameters (density and specific capacity of water, and thermal conductivity of sediments) that can be easily extracted from tabulated values under the assumption that they are homogeneous in the study area. In the case of the thermal conductivity, it is common to apply a standard value of 1.84 Wm-1 C-1 corresponding to sand. Nevertheless the environments where this method is applied, like streambeds or lake/lagoons shores, are sedimentary depositional systems with high energy and biological activity that often lead to sediments dominated by organic matter or sharp changes in grain size modifying greatly the thermal conductivity values. In this study, the thermal conductivity was measured in situ along transects where vertical temperature profiles were collected in a coastal lagoon bed receiving groundwater discharge (Ringkøbing Fjord, Denmark). A set of 4 transects with 10-20 temperature profiles during 3 different seasons was analyzed together with more than 150 thermal conductivity measurements along the working transects and in experimental parcels of 1 m2 where the cm scale spatial variability of the thermal conductivity was assessed. The application of a literature-based bulk thermal conductivity of 1.84 Wm-1 C-1 instead of field data that ranged from 0.62 to 2.19 Wm-1 C-1, produced a mean flux overestimation of 2.33 cm d-1 that, considering the low fluxes of the study area, represents an increase of 89 % and up to a factor of 3 in the most extreme cases. The changes in thermal conductivity can alter the estimated fluxes hindering the detection of patterns in groundwater discharge and modifying the interpretation of the results.

COMPARISON OF THE MORPHOLOGICAL TRANSFORMING ACTIVITIES OF FJORD-REGION PAHS WITH DIBENZO[A,E}PYRENE & BENZO{A}PYRENE

EPA Science Inventory

Po(l'cyclic Aromatic Compound" 1999, Vol. 16. pp. 141-149 ICJ 1999OPA (Overseas Publishers Associationl NV. Reprints available directly from the publisher Published by license under Photocopying permitted by license only the Gordon and Breach Science Publishers imprint.
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Chapter 15: Inland Habitat Suitability for the Marbled Murrelet in Southcentral Alaska

Treesearch

Katherine J. Kuletz; Dennis K. Marks; Nancy L. Naslund; Nike J. Goodson; Mary B. Cody

1995-01-01

The majority of Marbled Murrelets (Brachyramphus marmoratus) nest in Alaska, where they sometimes nest on the ground, and their nesting habitat requirements are not well understood. The inland activity of murrelets was surveyed, and habitat features measured, between 1991 and 1993, in Prince William Sound, Kenai Fjords National Park and Afognak...

In-Situ Observations of a Subglacial Outflow Plume in a Greenland Fjord

NASA Astrophysics Data System (ADS)

Mankoff, K. D.; Straneo, F.; Singh, H.; Das, S. B.

2014-12-01

We present oceanographic observations collected in and immediately outside of a buoyant, fresh, sediment-laden subglacial outflow plume rising up the marine-terminating front of Sarqardleq Glacier, Greenland (68.9 N, 50.4 W). Subglacial outflow plumes, associated with the discharge at depth of upstream glacial surface melt, entrain the relatively warm fjord waters and are correlated with enhanced submarine melt and increased calving. Few in-situ observations exist due to the challenges of making measurements at the calving front of glaciers. Our data were collected using a small boat, a helicopter, and a JetYak (a remote-controlled jet-ski-powered kayak). Temperature and salinity profiles in, around, and far from the plume are used to described its oceanographic properties, spatial extent, and temporal variability. This plume rises vertically up the ice front expanding laterally and away from the ice, over-shoots its stable isopycnal and reaches the surface. Its surface expression is identified by colder, saltier, sediment-laden water flowing at ~5 m/s away from the ice face. Within ~300 m from the ice it submerges as it seeks buoyant stability.

Direct Measurements of Iceberg Melt in Greenland Tidewater Glacier Fjords

NASA Astrophysics Data System (ADS)

Schild, K. M.; Sutherland, D.; Straneo, F.; Elosegui, P.

2017-12-01

The increasing input of freshwater to the subpolar North Atlantic, both through glacier meltwater runoff and the melting of calved icebergs, has significant implications for the Atlantic meridional overturning circulation and regional scale circulation. However, the magnitude and timing of this meltwater input has been challenging to quantify because iceberg melt rates are largely unknown. Here we use data from a simultaneous glaciological and oceanographic field campaign conducted in Sermilik Fjord, southeast Greenland, during July 2017 to map the surface and submarine geometry of large icebergs and use repeat surveys to directly measure iceberg melt rates. We use a combination of coincident ship-based multibeam submarine scans, ocean hydrography measurements, aerial drone mapping, and high precision iceberg-mounted GPS measurements to construct a detailed picture of iceberg geometry and melt. This synthesis of in situ iceberg melt measurements is amongst the first of its kind. Here, we will discuss the results of the 2017 field campaign, the implications of variable iceberg meltwater input throughout the water column, and comparisons to standard melt rate parameterizations and tidewater glacier submarine melt rate calculations.

Diversity of bacterial dimethylsulfoniopropionate degradation genes in surface seawater of Arctic Kongsfjorden.

PubMed

Zeng, Yin-Xin; Qiao, Zong-Yun; Yu, Yong; Li, Hui-Rong; Luo, Wei

2016-09-08

Dimethylsulfoniopropionate (DMSP), which is the major source of organic sulfur in the world's oceans, plays a significant role in the global sulfur cycle. This compound is rapidly degraded by marine bacteria either by cleavage to dimethylsulfide (DMS) or demethylation to 3-methylmercaptopropionate (MMPA). The diversity of genes encoding bacterial demethylation (dmdA) and DMS production (dddL and dddP) were measured in Arctic Kongsfjorden. Both dmdA and dddL genes were detected in all stations along a transect from the outer to the inner fjord, while dddP gene was only found in the outer and middle parts of the fjord. The dmdA gene was completely confined to the Roseobacter clade, while the dddL gene was confined to the genus Sulfitobacter. Although the dddP gene pool was also dominated by homologs from the Roseobacter clade, there were a few dddP genes showing close relationships to both Alphaproteobacter and Gammaproteobacter. The results of this study suggest that the Roseobacter clade may play an important role in DMSP catabolism via both demethylation and cleavage pathways in surface waters of Kongsfjorden during summer.

Numerical Simulations of Upstream Propagating Solitary Waves and Wave Breaking In A Stratified Fjord

NASA Astrophysics Data System (ADS)

Stastna, M.; Peltier, W. R.

In this talk we will discuss ongoing numerical modeling of the flow of a stratified fluid over large scale topography motivated by observations in Knight Inlet, a fjord in British Columbia, Canada. After briefly surveying the work done on the topic in the past we will discuss our latest set of simulations in which we have observed the gener- ation and breaking of three different types of nonlinear internal waves in the lee of the sill topography. The first type of wave observed is a large lee wave in the weakly strat- ified main portion of the water column, The second is an upward propagating internal wave forced by topography that breaks in the strong, near-surface pycnocline. The third is a train of upstream propagating solitary waves that, in certain circumstances, form as breaking waves consisting of a nearly solitary wave envelope and a highly unsteady core near the surface. Time premitting, we will comment on the implications of these results for our long term goal of quantifying tidally driven mixing in Knight Inlet.

Diversity of bacterial dimethylsulfoniopropionate degradation genes in surface seawater of Arctic Kongsfjorden

NASA Astrophysics Data System (ADS)

Zeng, Yin-Xin; Qiao, Zong-Yun; Yu, Yong; Li, Hui-Rong; Luo, Wei

2016-09-01

Dimethylsulfoniopropionate (DMSP), which is the major source of organic sulfur in the world’s oceans, plays a significant role in the global sulfur cycle. This compound is rapidly degraded by marine bacteria either by cleavage to dimethylsulfide (DMS) or demethylation to 3-methylmercaptopropionate (MMPA). The diversity of genes encoding bacterial demethylation (dmdA) and DMS production (dddL and dddP) were measured in Arctic Kongsfjorden. Both dmdA and dddL genes were detected in all stations along a transect from the outer to the inner fjord, while dddP gene was only found in the outer and middle parts of the fjord. The dmdA gene was completely confined to the Roseobacter clade, while the dddL gene was confined to the genus Sulfitobacter. Although the dddP gene pool was also dominated by homologs from the Roseobacter clade, there were a few dddP genes showing close relationships to both Alphaproteobacter and Gammaproteobacter. The results of this study suggest that the Roseobacter clade may play an important role in DMSP catabolism via both demethylation and cleavage pathways in surface waters of Kongsfjorden during summer.

The history of hexachlorobenzene accumulation in Svalbard fjords.

PubMed

Pouch, A; Zaborska, A; Pazdro, K

2018-05-24

In the present study, we investigated the spatial and historical trends of hexachlorobenzene (HCB) contamination in dated sediments of three Svalbard fjords (Kongsfjorden, Hornsund, Adventfjorden) differing in environmental conditions and human impact. HCB concentrations ranging from below limit of quantification (6.86 pg/g d.w.) to 143.99 pg/g d.w. were measured. The highest concentrations were measured in two surface sediment layers of the core collected in Hornsund near the melting glacier. The lowest concentrations of HCB were measured in Adventfjorden, suggesting that local source of HCB is not significant and global transport processes are the major transport pathways. The history of HCB deposition did not fully reflect the history of HCB emission (largest in 1950s and 1960s). In case of several sediment cores, the HCB enrichment in surface (recent) sediments was noticed. This can indicate importance of secondary sources of HCB, e.g., the influx of HCB accumulated over decades on the surface of glaciers. Detected levels of HCB were generally low and did not exceed background concentration levels; thus, a negative effect on benthic organisms is not expected.

Distribution, abundance, and habitat associations of a large bivalve (Panopea generosa) in a eutrophic, fjord estuary

USGS Publications Warehouse

Mcdonald, P. Sean; Essington, Timothy E.; Davis, Jonathan P.; Galloway, Aaron W.E.; Stevick, Bethany C.; Jensen, Gregory C.; VanBlaricom, Glenn R.; Armstrong, David A.

2015-01-01

Marine bivalves are important ecosystem constituents and frequently support valuable fisheries. In many nearshore areas, human disturbance—including declining habitat and water quality—can affect the distribution and abundance of bivalve populations, and complicate ecosystem and fishery management assessments. Infaunal bivalves, in particular, are frequently cryptic and difficult to detect; thus, assessing potential impacts on their populations requires suitable, scalable methods for estimating abundance and distribution. In this study, population size of a common benthic bivalve (the geoduck Panopea generosa) is estimated with a Bayesian habitat-based model fit to scuba and tethered camera data in Hood Canal, a fjord basin in Washington state. Densities declined more than two orders of magnitude along a north—south gradient, concomitant with patterns of deepwater dissolved oxygen, and intensity and duration of seasonal hypoxia. Across the basin, geoducks were most abundant in loose, unconsolidated, sand substrate. The current study demonstrates the utility of using scuba, tethered video, and habitat models to estimate the abundance and distribution of a large infaunal bivalve at a regional (385-km2) scale.

Educational and Vocational Guidance in Denmark. Education in Denmark.

ERIC Educational Resources Information Center

Ministry of Education, Copenhagen (Denmark).

This report sketches educational and vocational guidance in Denmark. It begins with a historical account of developments in the areas of career and school counseling. Outlined next are guidance programs at the following levels: folkeskole, gymnasium and studenterkursus (upper secondary education), higher preparatory examination, vocational school,…

The Financing of Vocational Education and Training in Denmark. Financing Portrait. CEDEFOP Panorama.

ERIC Educational Resources Information Center

Hansen, Martin Eggert

The financing of vocational education and training (VET) in Denmark was evaluated through consultations with various bodies, including the following: Denmark's Ministry of Labor and Ministry of Education, Danish Employer's Confederation, Confederation of Danish Industry, Danish Confederation of Trade Unions, Association of County Councils, and…

76 FR 13890 - Importation of Bromeliad Plants in Growing Media From Belgium, Denmark, and the Netherlands

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-15

... in Growing Media From Belgium, Denmark, and the Netherlands AGENCY: Animal and Plant Health..., Cryptanthus, Guzmania, Hohenbergia, Neoregelia, Tillandsia, and Vriesea from Belgium, Denmark, and the... regulations in ``Subpart--Nursery Stock, Plants, Roots, Bulbs, Seeds, and Other Plant Products,'' Sec. Sec...

26 CFR 521.101 - Introductory.

Code of Federal Regulations, 2010 CFR

2010-04-01

... DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish... representative; and in the case of Denmark, the Chief of the Taxation Department of the Ministry of Finance... III (1) An enterprise of one of the contracting States shall not be subject to taxation in the other...

Observations of The Dense Storfjord Plume Using A Ctd-mounted Adp

NASA Astrophysics Data System (ADS)

Fer, I.; Skogseth, R.; Haugan, P. M.

Observations were made of the outflow of the dense bottom water plume from Stor- fjord (110 km long and 190 m deep at maximum depth) in the Svalbard Archipelago, using a CTD mounted ADP at densely spaced hydrographic stations during May 28 - June 2, 2001. Due to heavy ice inside the fjord, measurements were made from about 70 km downstream of a 115 m deep sill (7645 N) and onward. The dense bottom water generated by strong winter cooling, enhanced ice formation, and the consequent brine rejection drains into and fills the depressions of the fjord and cascades following the bathymetry. Data acquired by ADP allow for examination of the velocity structure associated with the plume as close as 1 m to the bottom with 1 m resolution in the vertical. The plume water was observed to have salinities within 34.9 - 35.1 psu with temperatures close to the freezing point temperature. The plume has a thickness of 51 +/- 20 m, and a density difference of 0.14 +/- 0.03 kg m-3 from the ambient wa- ters. The velocity profiles yield the most well-defined two-layered structure near the sloping sides with a mean plume speed of 0.15 +/- 0.04 m s-1, relative to the ambient waters. Mean overall Richardson number, estimated using these profiles, are within the range of 2 to 4. The plume is less distinct with respect to the velocity profile when it reaches the plane, Storfjordrenna, after cascading about 50 m in vertical. The width of the plume increases from about 8 km to 25 km along its path of 105 km leading to an entrainment rate of 5x10-4, when the plume thickness and speed are assumed constant. The values compare well with those obtained from moorings in the same region in the past, as well as those obtained from laboratory experiments of turbulent gravity currents flowing down a slope.

The influence of permanently submerged macrophytes on sediment mercury distribution, mobility and methylation potential in a brackish Norwegian fjord.

PubMed

Olsen, Marianne; Schaanning, Morten Thorne; Braaten, Hans Fredrik Veiteberg; Eek, Espen; Moy, Frithjof E; Lydersen, Espen

2018-01-01

Macrophytes are shown to affect the microbial activity in different aqueous environments, with an altering of the sediment cycling of mercury (Hg) as a potential effect. Here, we investigated how a meadow with permanently submerged macrophytes in a contaminated brackish fjord in southern Norway influenced the conditions for sulfate reducing microbial activity, the methyl-Hg (MeHg) production and the availability of MeHg. Historically discharged Hg from a chlor-alkali plant (60-80tons, 1947-1987) was evident through high Hg concentrations (491mgTot-Hgkg -1 , 268μgMeHgkg -1 ) in intermediate sediment depths (10-20cm) outside of the meadow, with reduced concentrations within the meadow. Natural recovery of the fjord was revealed by lower sediment surface concentrations (1.9-15.5mgTot-Hgkg -1 , 1.3-3.2μgMeHgkg -1 ). Within the meadow, vertical gradients of sediment hydrogen sulfide (H 2 S) E h and pH suggested microbial sulfate reduction in 2-5cm depths, coinciding with peak values of relative MeHg levels (0.5% MeHg). We assume that MeHg production rates was stimulated by the supply and availability of organic carbon, microbial activity and a sulfide oxidizing agent (e.g. O 2 ) within the rhizosphere. Following this, % MeHg in sediment (0-5cm) within the meadow was approximately 10× higher compared to outside the meadow. Further, enhanced availability of MeHg within the meadow was demonstrated by significantly higher fluxes (p<0.01) from sediment to overlying water (0.1-0.6ngm -2 d -1 ) compared to sediment without macrophytes (0.02-0.2ngm -2 d -1 ). Considering the productivity and species richness typical for such habitats, submerged macrophyte meadows located within legacy Hg contaminated sediment sites may constitute important entry points for MeHg into food webs. Copyright © 2017 Elsevier B.V. All rights reserved.

Depositional settings and evolution of a fjord system during the carboniferous glaciation in Northwest Argentina

NASA Astrophysics Data System (ADS)

Alonso-Muruaga, Pablo J.; Limarino, Carlos O.; Spalletti, Luis A.; Colombo Piñol, Ferrán

2018-07-01

Fjord systems, represented by glacial diamictites and postglacial transgressive shales, formed in the basins of western Argentina during the late Carboniferous Gondwana glaciation. Well exposed fjord deposits of the Guandacol Formation were studied in the Loma de Los Piojos region (Protoprecordillera), where they fill a 2.9 km wide paleovalley with steep side walls and a relatively flat floor. The valley cross-cuts Lower Devonian sandstones and Mississippian mudstones and sandstones, and provides evidence of glacial abrasion, including striated pavements and glacial microtopography (grooves, ridges, and striae). Based on the analysis of seven sedimentary logs, eight sedimentary facies in the valley fill were recognized: (A) Massive diamictites; (B) Laminated mudstones with dropstones; (C) Stratified diamictites; (D) Clast-supported conglomerates and sandstones; (E) Deformed diamictites, conglomerates and sandstones; (F) Folded diamictites; (G) Mudstones interbedded with sandstones, and (H) Stacked and amalgamated sandstones. These sedimentary facies are grouped into two principal facies assemblages that represent different stages of the paleovalley fill. Assemblage 1 is composed of diamictites (Facies A, C and F), laminated mudstones with dropstones (Facies B), and conglomerates (Facies D and E), which represent glacially influenced sedimentation in the paleovalley. Assemblage 2 represents the paleovalley fill when glacial influence ceased, and comprises laminated mudstones interbedded with sandstones (facies G) and stacked sandstone beds (facies H) that mostly record deltaic sedimentation. Stratigraphic relationships, plant fossils found in the paleovalley walls and palynological assemblages recovered in mudstones of facies D help to establish an early Pennsylvanian age for both the incision and the filling of the paleovalley. The studied paleovalley records an exceptional example of the western Gondwanan glacial to postglacial transition. Due to the continuous stratigraphic succession within the paleovalley as well as palynological, megafloristic and radiometric data, this example provides a complete framework of the late Carboniferous postglacial evolution in western Gondwana.

Temporal variability of air-sea CO2 exchange in a low-emission estuary

NASA Astrophysics Data System (ADS)

Mørk, Eva Thorborg; Sejr, Mikael Kristian; Stæhr, Peter Anton; Sørensen, Lise Lotte

2016-07-01

There is the need for further study of whether global estimates of air-sea CO2 exchange in estuarine systems capture the relevant temporal variability and, as such, the temporal variability of bulk parameterized and directly measured CO2 fluxes was investigated in the Danish estuary, Roskilde Fjord. The air-sea CO2 fluxes showed large temporal variability across seasons and between days and that more than 30% of the net CO2 emission in 2013 was a result of two large fall and winter storms. The diurnal variability of ΔpCO2 was up to 400 during summer changing the estuary from a source to a sink of CO2 within the day. Across seasons the system was suggested to change from a sink of atmospheric CO2 during spring to near neutral during summer and later to a source of atmospheric CO2 during fall. Results indicated that Roskilde Fjord was an annual low-emission estuary, with an estimated bulk parameterized release of 3.9 ± 8.7 mol CO2 m-2 y-1 during 2012-2013. It was suggested that the production-respiration balance leading to the low annual emission in Roskilde Fjord, was caused by the shallow depth, long residence time and high water quality in the estuary. In the data analysis the eddy covariance CO2 flux samples were filtered according to the H2Osbnd CO2 cross-sensitivity assessment suggested by Landwehr et al. (2014). This filtering reduced episodes of contradicting directions between measured and bulk parameterized air-sea CO2 exchanges and changed the net air-sea CO2 exchange from an uptake to a release. The CO2 gas transfer velocity was calculated from directly measured CO2 fluxes and ΔpCO2 and agreed to previous observations and parameterizations.

Late Weichselian ice-sheet dynamics and deglaciation history of the northern Svalbard margin

NASA Astrophysics Data System (ADS)

Fransner, O.; Noormets, R. R. N. N.; Flink, A.; Hogan, K.; Dowdeswell, J. A.; O'Regan, M.; Jakobsson, M.

2016-12-01

The glacial evolution of the northern Svalbard margin is poorly known compared with the western margin. Gravity cores, swath bathymetric, sub-bottom acoustic and 2D airgun data are used to investigate the Late Weichselian Svalbard-Barents Ice Sheet history on the northern Svalbard margin. Prograding sequences in Kvitøya and Albertini trough mouths (TMs) indicate ice streaming to the shelf edge multiple times during the Quaternary. While Kvitøya Trough has an associated trough-mouth fan (TMF), Albertini TM is cut back into the shelf edge. Down-faulted bedrock below Albertini TM suggests larger sediment accommodation space there, explaining the absence of a TMF. The bathymetry indicates that ice flow in Albertini Trough was sourced from Duvefjorden and Albertinibukta. Exposed crystalline bedrock likely kept the two ice flows separated before merging north of Karl XII-Øya. Subglacial landforms in Rijpfjorden and Duvefjorden indicate that both fjords accommodated northward-flowing ice streams during the LGM. The deeper fjord basin and higher elongation ratios of landforms in Duvefjorden suggest a more focused and/or larger ice flow there. Easily erodible sedimentary rocks are common in Duvefjorden, which may explain different ice flow dynamics in these fjords. Kvitøya TMF is flanked by gullies, probably formed through erosive downslope gravity flows triggered by sediment-laden meltwater during early deglaciation. Glacial landforms in Albertini Trough comprise retreat-related landforms indicating slow deglaciation. Iceberg scours in Albertini Trough suggest the importance of calving for mass-loss. Sets of De Geer moraines in Rijpfjorden imply that slow, grounded retreat continued in <210 m water depth. Lack of retreat-related landforms in deeper areas of Rijpfjorden and in Duvefjorden indicates floating glacier fronts influenced by calving. 14C ages suggest that deglaciation of inner Rijpfjorden and central Duvefjorden were complete before 10,434 cal a BP and 10,779 cal a BP respectively.

Role of resting cysts in Chilean Alexandrium catenella dinoflagellate blooms revisited.

PubMed

Mardones, Jorge I; Bolch, Chris; Guzmán, Leonardo; Paredes, Javier; Varela, Daniel; Hallegraeff, Gustaaf M

2016-05-01

The detection of sparse Alexandrium catenella-resting cysts in sediments of southern Chilean fjords has cast doubts on their importance in the recurrence of massive toxic dinoflagellate blooms in the region. The role of resting cysts and the existence of different regional Chilean populations was studied by culturing and genetic approaches to define: (1) cyst production; (2) dormancy period; (3) excystment success; (4) offspring viability and (5) strain mating compatibility. This study newly revealed a short cyst dormancy (minimum 69 days), the role of key abiotic factors (in decreasing order salinity, irradiance, temperature and nutrients) controlling cyst germination (max. 60%) and germling growth rates (up to 0.36-0.52div.day -1 ). Amplified fragment length polymorphism (AFLP) characterization showed significant differences in genetic distances (GD) among A. catenella populations that were primarily determined by the geographical origin of isolates and most likely driven by oceanographic dispersal barriers. A complex heterothallic mating system pointed to variable reproductive compatibility (RCs) among Chilean strains that was high among northern (Los Lagos/North Aysén) and southern populations (Magallanes), but limited among the genetically differentiated central (South Aysén) populations. Field cyst surveys after a massive 2009 bloom event revealed the existence of exceptional high cyst densities in particular areas of the fjords (max. 14.627cystscm -3 ), which contrast with low cyst concentrations (<221.3cystscm -3 ) detected by previous oceanographic campaigns. In conclusion, the present study suggests that A. catenella resting cysts play a more important role in the success of this species in Chilean fjords than previously thought. Results from in vitro experiments suggest that pelagic-benthic processes can maintain year-round low vegetative cell concentrations in the water column, but also can explain the detection of high cysts aggregations after the 2009-bloom event. Regional drivers that lead to massive outbreaks, however, are still unknown but potential scenarios are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydroacoustic habitat mapping in Potter Cove (King George Island, Antarctica)

NASA Astrophysics Data System (ADS)

Hass, H. Christian; Wölfl, Anne-Cathrin; Kuhn, Gerhard; Jerosch, Kerstin; Scharf, Frauke; Abele, Doris

2016-04-01

Climate change increasingly affects the coastal areas off Antarctica. Strongest environmental response occurs in the transition zones that mediate between the polar and subpolar latitudes. Potter Cove, a minor fjord at the northern tip of the Antarctic Peninsula is significantly affected by rising temperatures and retreating ice sheets. Large amounts of turbid meltwaters affect both, the seafloor and the water column and cause stress for many biota. There is an increasing demand to monitor the ongoing change and to work out means for comparison with similar coastal ecosystems under pressure. Marine habitat maps provide information on the seafloor characteristics that allow to describe and evaluate the status of the recent coastal ecosystem and to predict its future development. We used a RoxAnn acoustic ground discrimination system, a sidescan sonar, grab samples (grain size and TOC) and underwater video footage to gain habitat information. Supervised and unsupervised classification routines (including fuzzy k-means clustering and LDA) were employed to calculate models ranging from two classes (soft bottom habitat, stone habitat) to 7 classes (including classes of rocks with and without macroalgae as well as classes of gravels, sands and silts). Including organic carbon in the database allowed to identify a carbon-depleted class proximal to the glacier front. Potter Cove reveals features that are related to the climate-controlled environmental change: very rough seafloor topography in a small basin close to the fjord head which was cleared by the retreating tidewater glacier through the past two decades. The increasing distance to the glacier down-fjord causes existing habitats to smooth and mature and new habitats to form. This process will change the terrestrial and marine face of Potter Cove until the ongoing climatic change stops or even reverses. It becomes apparent that the final interpretation of the results benefits significantly from the different discrimination and classification approaches.

Initial Insights into the Quaternary Evolution of the Laurentide Ice Sheet on Southeastern Baffin Island

NASA Astrophysics Data System (ADS)

Pendleton, S.; Anderson, R. S.; Miller, G. H.; Refsnider, K. A.

2015-12-01

Increasing Arctic summer temperatures in recent decades and shrinking cold-based ice caps on Cumberland Peninsula, Baffin Island, are exposing ancient landscapes complete with uneroded bedrock surfaces. Previous work has indicated that these upland surfaces covered with cold-based ice experience negligible erosion compared with the valleys and fjords systems that contain fast-flowing ice. Given the appearance of highly weathered bedrock, it is argued that these landscapes have remained largely unchanged since at least the last interglaciation (~120 ka), and have likely experienced multiple cycles of ice expansion and retraction with little erosion throughout the Quaternary. To explore this hypothesis, we use multiple cosmogenic radionuclides (26Al and 10Be) to investigate and provide insight into longer-term cryosphere activity and landscape evolution. 26Al/10Be in surfaces recently exposed exhibit a wide range of exposure-burial histories. Total exposure-burial times range from ~0.3 - 1.5 My and estimated erosion rates from 0.5 - 6.2 m Ma-1. The upland surfaces of the Penny Ice cap generally experienced higher erosion rates (~0.45 cm ka-1) than those covered by smaller ice caps (~0.2 cm ka-1). The cumulative burial/exposure histories in high, fjord-edge locations indicate that significant erosion north of the Penny Ice Cap ceased between ~600 and 800 ka, suggesting that Laurentide Ice Sheet (LIS) organization and fjord inception was underway by at least this time. Additionally, 26Al/10Be ratios near production values despite high inventories from a coastal summit 50 km east of the Penny Ice Cape suggest that that area has not experienced appreciable burial by ice, suggesting that it was never inundated by the LIS. Moreover, these initial data suggest a variable and dynamic cryosphere in the region and provide insight into how large ice sheets evolved and organized themselves during the Quaternary.

Postglacial Records of Southern Hemisphere Climate and Oceanographic Change From the New Zealand Subantarctic Auckland Islands

NASA Astrophysics Data System (ADS)

Moy, C. M.; Gilmer, G.; Nichols, J. E.; Browne, I. M.; Curtin, L.; Vandergoes, M.; Aebig, C.; Wilson, G. S.

2017-12-01

The strength and latitudinal position of the Southern Hemisphere westerly winds (SHWW) play a fundamental role in influencing mid-latitude climate and CO2 exchange between the Southern Ocean and the atmosphere along seasonal to glaicial-interglacial timescales. Despite their importance, our understanding of past SHWW change is limited by the small number of paleoclimate records from the modern wind maximum, which are often not in agreement. The New Zealand subantarctic Auckland Islands are located within the core of the modern wind belt (50°S), a key latitude where ocean-atmospheric linkages between the Antarctic and mid-latitudes are strong. In contrast to other subantarctic islands on the Campbell Plateau, the Auckland Islands have multiple protected fjord sub-basins, deep lakes, and peatlands that are advantageous for the development of high-resolution paleoclimate records. We will present ongoing work towards the establishment of multi-proxy and multi-site reconstructions of past SHWW variability from the Auckland Islands. Modern process and paleoclimate studies suggest that in lacustrine and fjord settings, the degree of water column mixing, the stable isotopic composition of n-alkanes and benthic foraminifera, and the influx of terrestrial organic matter are good indicators of wind-induced mixing of the water column or precipitation-driven erosion within catchments. During the Late Glacial and early Holocene (15 to 9 ka), elevated long-chain n-alkane δD values from ombrotrophic peatlands and an increase in the concentration of redox-sensitive elements in fjord sediment cores, signal weakening of the SHWW that appears to be coincident with periods of rapid deglacial warming of West Antarctica. Since 5.5 ka, we interpret declining n-alkane δD values to indicate enhanced westerly flow. These interpretations are in broad agreement with terrestrial paleoclimate records developed from southern South America and argue for a symmetrical response of the SHWW during the last 15,000 years along multi-millennial timescales.

Impacts of 21st century climate changes on flora and vegetation in Denmark

NASA Astrophysics Data System (ADS)

Skov, Flemming; Nygaard, Bettina; Wind, Peter; Borchsenius, Finn; Normand, Signe; Balslev, Henrik; Fløjgaard, Camilla; Svenning, Jens-Christian

2009-11-01

In this paper we examined the potential impacts of predicted climatic changes on the flora and vegetation in Denmark using data from a digital database on the natural vegetation of Europe. Climate scenarios A2 and B2 were used to find regions with present climatic conditions similar to Denmark's climate in the year 2100. The potential natural vegetation of Denmark today is predominantly deciduous forest that would cover more than 90% of the landscape. Swamps, bogs, and wet forest would be found under moist or wet conditions. Dwarf shrub heaths would be naturally occurring on poor soils along the coast together with dune systems and salt-marsh vegetation. When comparing the natural vegetation of Denmark to the vegetation of five future-climate analogue areas, the most obvious trend is a shift from deciduous to thermophilous broadleaved forest currently found in Southern and Eastern Europe. A total of 983 taxa were recorded for this study of which 539 were found in Denmark. The Sørensen index was used to measure the floristic similarity between Denmark and the five subregions. Deciduous forest, dwarf shrub heath, and coastal vegetation were treated in more detail, focusing on potential new immigrant species to Denmark. Finally, implications for management were discussed. The floristic similarity between Denmark and regions in Europe with a climate similar to what is expected for Denmark in year 2100 was found to vary between 48-78%, decreasing from North to South. Hence, it seems inevitable that climate changes of the magnitudes foreseen will alter the distribution of individual species and the composition of natural vegetation units. Changes, however, will not be immediate. Historic evidence shows a considerable lag in response to climatic change under natural conditions, but little is known about the effects of human land-use and pollution on this process. Facing such uncertainties we suggested that a dynamic strategy based on modeling, monitoring and adaptive management is adopted. Modeling techniques can be constantly improved, but will never be perfect and should therefore be linked to a fine-masked network of observatories to check model predictions and feed empirical data back into the models for calibration and further development.

Glacier inputs influence organic matter composition and prokaryotic distribution in a high Arctic fjord (Kongsfjorden, Svalbard)

NASA Astrophysics Data System (ADS)

Bourgeois, Solveig; Kerhervé, Philippe; Calleja, Maria Ll.; Many, Gaël; Morata, Nathalie

2016-12-01

With climate change, the strong seasonality and tight pelagic-benthic coupling in the Arctic is expected to change in the next few decades. It is currently unclear how the benthos will be affected by changes of environmental conditions such as supplies of organic matter (OM) from the water column. In the last decade, Kongsfjorden (79°N), a high Arctic fjord in Svalbard influenced by several glaciers and Atlantic water inflow, has been a site of great interest owing to its high sensitivity to climate change, evidenced by a reduction in ice cover and an increase in melting freshwater. To investigate how spatial and seasonal changes in vertical fluxes can impact the benthic compartment of Kongsfjorden, we studied the organic matter characteristics (in terms of quantity and quality) and prokaryotic distribution in sediments from 3 stations along a transect extending from the glacier into the outer fjord in 4 different seasons (spring, summer, autumn and winter) in 2012-2013. The biochemical parameters used to describe the sedimentary organic matter were organic carbon (OC), total nitrogen, bulk stable isotope ratios, pigments (chorophyll-a and phaeopigments) and biopolymeric carbon (BPC), which is the sum of the main macromolecules, i.e. lipids, proteins and carbohydrates. Prokaryotic abundance and distribution were estimated by 4‧,6-diamidino-2-phenylindole (DAPI) staining. This study identifies a well-marked quantitative gradient of biogenic compounds throughout all seasons and also highlights a discrepancy between the quantity and quality of sedimentary organic matter within the fjord. The sediments near the glacier were organic-poor (< 0.3%OC), however the high primary productivity in the water column displayed during spring was reflected in summer sediments, and exhibited higher freshness of material at the inner station compared to the outer basin (means C-chlorophyll-a/OC 5 and 1.5%, respectively). However, sediments at the glacier front were depleted in BPC ( 0.2-0.3 mg C g- 1 DW) by 4.5 and 9 times compared to sediments from the inner and outer stations. δ13C values in sedimentary organic matter of Kongsfjorden varied between - 23.8 and - 19.3‰ and reflected distinct sources of organic matter between basins. Bacterial total cell numbers in sediments of Kongsfjorden were < 2 × 108 cells ml- 1 and the prokaryotic community structure was strongly influenced by the marked environmental biogenic gradients. Overall, the spatial variability prevailed over the seasonal variability in sediments of Kongsfjorden suggesting that glacier inputs prominently control the functioning of this benthic ecosystem and its communities. Regional index terms: Norway, Svalbard, Kongsfjorden.

Combined terrestrial and marine biomarker records from an Icelandic fjord: insights into Holocene climate drivers and marine/ terrestrial responses

NASA Astrophysics Data System (ADS)

Moossen, H. M.; Seki, O.; Quillmann, U.; Andrews, J. T.; Bendle, J. A.

2012-12-01

Holocene climate change has affected human cultures throughout at least the last 4000 years (D'Andrea et al., 2011). Today, studying Holocene climate variability is important, both to constrain the influence of climate change on ancient cultures and to place contemporary climate change in a historic context. Organic geochemical biomarkers are an ideal tool to study how climatic changes have affected terrestrial and marine ecosystems, as a host of different biomarker based climate proxies have emerged over recent years. Applying the available biomarker proxies on sediment cores from fjordic environments facilitates the study of how climate has affected terrestrial and marine ecosystems, and how these ecosystems have interacted. Ìsafjardardjúp fjord in Northwest Iceland is an ideal location to study North Atlantic Holocene climate change because the area is very sensitive to changes in the oceanic and atmospheric current systems (Hurrell, 1995; Quillmann et al., 2010). In this study we present high resolution (1 sample/30 calibrated years) terrestrial and marine biomarker records from a 38 m sediment core from Ìsafjardardjúp fjord covering the Holocene. We reconstruct sea surface temperature variations using the alkenone derived UK'37 proxy. Air temperature changes are reconstructed using the GDGT derived MBT/CBT palaeothermometer. We use the average chain length (ACL) variability of n-alkanes derived from terrestrial higher plant leaf waxes to reconstruct changing precipitation regimes. The relationship between ACL and precipitation is confirmed by comparing it with the δD signature of the C29 n-alkane and soil pH changes inferred by the CBT proxy. The combined sea surface and air temperature and precipitation records indicate that different climate changing drivers were dominant at different stages of the Holocene. Sea surface temperatures were strongly influenced by the melting of the remaining glaciers from the last glacial maximum throughout the early Holocene, while air temperatures were influenced by high solar insolation. The central Holocene climate is mainly driven by decreasing northern hemisphere insolation, while the lateral transport of energy from the equator into the North Atlantic region drives climate change in the late Holocene. D'Andrea, W.J., Huang, Y., Fritz, S.C., Anderson, N.J., (2011) Abrupt Holocene climate change as an important factor for human migration in West Greenland. Proceedings of the National Academy of Sciences of the United States of America, 108(24), 9765-9769. Hurrell, J.W., (1995) Decadal trends in the North Atlantic Oscillation - Regional temperatures and precipitation. Science, 269(5224), 676-679. Quillmann, U., Jennings, A., Andrews, J., (2010) Reconstructing Holocene palaeoclimate and palaeoceanography in Isafjaroardjup, northwest Iceland, from two fjord records overprinted by relative sea-level and local hydrographic changes. Journal of Quaternary Science, 25(7), 1144-1159.

Denmark's Master of Public Governance Program: Assessment and Lessons Learned

ERIC Educational Resources Information Center

Greve, Carsten; Pedersen, Anne Reff

2017-01-01

This paper focuses on Denmark's Master of Public Governance and its assessments and lessons learned. Denmark is seen to have an efficient economy and public sector, a digitalized public service delivery system, and an advanced work-life balance. The Danish government invested substantial resources into developing a Master of Public Governance…

Sickness absence patterns and trends in the health care sector: 5-year monitoring of female municipal employees in the health and care sectors in Norway and Denmark

PubMed Central

2014-01-01

Background Sickness absence is a growing public health problem in Norway and Denmark, with the highest absence rates being registered in Norway. We compared time trends in sickness absence patterns of municipal employees in the health and care sectors in Norway and Denmark. Methods Data from 2004 to 2008 were extracted from the personnel registers of the municipalities of Kristiansand, Norway, and Aarhus, Denmark, for 3,181 and 8,545 female employees, respectively. Age-specific comparative statistics on sickness absence rates (number of calendar days of sickness absence/possible working days) and number of sick leave episodes were calculated for each year of the study period. Results There was an overall increasing trend in sickness absence rates in Denmark (P = 0.002), where rates were highest in the 20–29- (P = 0.01) and 50–59-year-old age groups (P = 0.03). Sickness absence rates in Norway were stable, except for an increase in the 20–29-year-old age group (P = 0.004). In both Norway and Denmark, the mean number of sick leave episodes increased (P <0.0001 and P <0.0001, respectively) in all age groups except for the 30–39- and 60–67-year-old age groups. The proportion of employees without sickness absence was higher in Norway than in Denmark. Both short-term and long-term absence increased in Denmark (P = 0.003 and P <0.0001, respectively), while in Norway, only short-term absence increased (P = 0.09). Conclusions We found an overall increase in sickness absence rates in Denmark, while the largest overall increase in sick leave episodes was found in Norway. In both countries, the largest increases were observed among young employees. The results indicate that the two countries are converging in regard to sickness absence measured as rates and episodes. PMID:25005027

Children's Perspective on Learning: An International Study in Denmark, Estonia, Germany and Sweden

ERIC Educational Resources Information Center

Sandberg, Anette; Broström, Stig; Johansson, Inge; Frøkjaer, Thorleif; Kieferle, Christa; Seifert, Anja; Roth, Angela; Tuul, Maire; Ugaste, Aino; Laan, Meeli

2017-01-01

This article explores how some children in Denmark, Estonia, Germany and Sweden describe their perspective on learning. The aim of the international study is to gain knowledge of how preschool children in Sweden, Denmark, Estonia and Germany reflect and perceive their learning in preschool and other surrounding social contexts. The results are…

Forest restoration in the Nordic countries

Treesearch

Palle Madsen; Ása Arad•ttir; Emile Gardiner; Pelle Gemmel; Kåre Lund Høie; Magnus Löf; John A. Stanturf; Peter Tigerstedt; Hardi Tullus; Sauli Valkonen; Veiko Uri

2000-01-01

The Nordic countries include Iceland, Norway, Sweden, Finland, and Denmark, which range from lat. 54° in southern Denmark to lat. 72° at North Cape, Norway. This region is dominated by the boreal coniferous vegetational zone.Denmark and southern Sweden are, however, located in the deciduous (nemoral) forest zone, whereas the interior part of Iceland and the high...

Changing Patterns of Finance in Higher Education. Country Study: Denmark. OECD Educational Monographs.

ERIC Educational Resources Information Center

Enslev, Lisbeth; And Others

A country study on Denmark is presented as part of a series prepared by the Organisation for Economic Cooperation and Development (OCED) Education Committee activity on changing patterns of finance in higher education. In Denmark, postsecondary institutions are the direct responsibility of the state. Some central problems are to strike a balance…

Library Services to the Homebound Elderly in Denmark.

ERIC Educational Resources Information Center

Nielsen, Gyda Skat

The number of elderly people in Denmark continues to grow, which means there is an increasing need for special library services to those elderly who are not able to come to the library because of physical or mental limitations. This paper uses the practices of Sollerod Public Libraries (Sollerod, Denmark) to frame the discussion of the following:…

Differences in cancer awareness and beliefs between Australia, Canada, Denmark, Norway, Sweden and the UK (the International Cancer Benchmarking Partnership): do they contribute to differences in cancer survival?

PubMed Central

Forbes, L J L; Simon, A E; Warburton, F; Boniface, D; Brain, K E; Dessaix, A; Donnelly, C; Haynes, K; Hvidberg, L; Lagerlund, M; Lockwood, G; Tishelman, C; Vedsted, P; Vigmostad, M N; Ramirez, A J; Wardle, J

2013-01-01

Background: There are wide international differences in 1-year cancer survival. The UK and Denmark perform poorly compared with other high-income countries with similar health care systems: Australia, Canada and Sweden have good cancer survival rates, Norway intermediate survival rates. The objective of this study was to examine the pattern of differences in cancer awareness and beliefs across these countries to identify where these might contribute to the pattern of survival. Methods: We carried out a population-based telephone interview survey of 19 079 men and women aged ⩾50 years in Australia, Canada, Denmark, Norway, Sweden and the UK using the Awareness and Beliefs about Cancer measure. Results: Awareness that the risk of cancer increased with age was lower in the UK (14%), Canada (13%) and Australia (16%) but was higher in Denmark (25%), Norway (29%) and Sweden (38%). Symptom awareness was no lower in the UK and Denmark than other countries. Perceived barriers to symptomatic presentation were highest in the UK, in particular being worried about wasting the doctor's time (UK 34% Canada 21% Australia 14% Denmark 12% Norway 11% Sweden 9%). Conclusion: The UK had low awareness of age-related risk and the highest perceived barriers to symptomatic presentation, but symptom awareness in the UK did not differ from other countries. Denmark had higher awareness of age-related risk and few perceived barriers to symptomatic presentation. This suggests that other factors must be involved in explaining Denmark's poor survival rates. In the UK, interventions that address barriers to prompt presentation in primary care should be developed and evaluated. PMID:23370208

Testicular cancer risk in first- and second-generation immigrants to Denmark.

PubMed

Myrup, Charlotte; Westergaard, Tine; Schnack, Tine; Oudin, Anna; Ritz, Christian; Wohlfahrt, Jan; Melbye, Mads

2008-01-02

Immigrant studies offer insights into the relative importance of environment and genes in disease etiology. There is considerable variation in testicular cancer incidence worldwide. We investigated testicular cancer risk in first- and second-generation immigrants to Denmark, a high-incidence country, to evaluate the relative influence of genes and environment and the potential timing of action of environmental factor(s). A cohort of 2.1 million men who were born since 1930 and lived in Denmark between 1968 and 2003 was established based on information in the Danish Civil Registration System, which included their immigration histories. Cancer histories were obtained from the Danish Cancer Registry. Testicular cancer risk was estimated as rate ratios (RRs) with 95% confidence intervals (CIs) based on log-linear Poisson regression. Overall, 4216 testicular cancer cases occurred during 43 million person-years of follow-up in 2.1 million men. These included 166 cases among 344,444 direct immigrants to Denmark and 13 cases among 56,189 men born in Denmark to immigrant parents. These first- and second-generation immigrants had RRs of testicular cancer of 0.37 (95% CI = 0.31 to 0.43) and 0.88 (95% CI = 0.51 to 1.53), respectively, compared with men born in Denmark of parents born in Denmark. The rate in first-generation immigrants was not modified by age at immigration or duration of stay and reflected that in the country of origin. The testicular cancer risk in first-generation immigrants was lower than that in native-born Danes and reflected that in the countries of origin, whereas the risk in second-generation immigrants was similar to that in natives of Denmark. Together these findings argue for a substantial influence of environmental factors limited to the period early in life, most probably to the period in utero.

Mapping telemedicine efforts: surveying regional initiatives in Denmark.

PubMed

Kierkegaard, Patrick

2015-05-01

The aim of this study is to survey telemedicine services currently in operation across Denmark. The study specifically seeks to answer the following questions: What initiatives are deployed within the different regions? What are the motivations behind the projects? What technologies are being utilized? What medical disciplines are being supported using telemedicine systems? All data were surveyed from the Telemedicinsk Landkort, a newly created database designed to provide a comprehensive and systematic overview of all telemedicine technologies in Denmark. The results of this study suggest that a growing numbers of telemedicine initiatives are currently in operation across Denmark but that considerable variations exist in terms of regional efforts as the number of operational telemedicine projects varied from region to region. The results of this study provide a timely picture of the factors that are shaping the telemedicine landscape of Denmark and suggest potential strategies to help policymakers increase and improve national telemedicine deployment.

New hypotheses regarding the Danish health puzzle.

PubMed

Bakah, May; Raphael, Dennis

2017-12-01

Nordic welfare states have achieved admirable population health profiles as a result of public policies that provide economic and social security across the life course. Denmark has been an exception to this rule, as its life expectancies and infant mortality rates since the mid-1970s have lagged behind the other Nordic nations and, in the case of life expectancy, behind most Organisation for Economic Co-operation and Development nations. In this review paper, we identify a number of new hypotheses for why this may be the case. These hypotheses concern the health effects of neo-liberal restructuring of the economy and its institutions, the institution of flexi-security in Denmark's labour market and the influence of Denmark's tobacco and alcohol industries. Also of note is that Denmark experienced higher unemployment rates during its initial period of health stagnation, as well as its treatment of non-Western immigrants and high wealth inequality and, until recently, the fact that Denmark did not systematically address the issue of health inequalities. These hypotheses may serve as covering explanations for the usually provided accounts of elevated behavioural risks and psychosocial stress as being responsible for Denmark's health profile.

Small-scale cannabis growers in Denmark and Finland.

PubMed

Hakkarainen, Pekka; Frank, Vibeke Asmussen; Perälä, Jussi; Dahl, Helle Vibeke

2011-01-01

To compare domestic cannabis cultivation in Denmark and Finland to describe national characteristics in small-scale cannabis growing. A Web survey conducted among small-scale cannabis growers in Denmark (June to November 2008) and Finland (May to June 2009). Current cannabis growers (Denmark, 401; Finland, 1,054). Comparisons in regard to social background, growing history, practices, purposes and motives of growing, and perceptions of risks. Cannabis was cultivated primarily for own use, but sharing with friends and avoiding criminal circles also were significant motives for growing. Finnish growers prioritized indoor cultivation, whereas the Danes were more in favor of open-air plantations. Risks of getting caught by the police were observed to be greater in Finland. Growing for medical purposes was twice as prevalent in Finland as in Denmark. Cannabis growing is a stronger and more novel phenomenon in Finland than in Denmark, but both countries have been influenced by international trends. Finnish and Danish small-scale cannabis cultivators can be considered to be ideologically oriented lifestyle growers. Differences in the magnitude of the phenomenon may reflect differences in the availability and quality of cannabis in national drug markets. The Internet had promoted the spreading of the trend. Copyright © 2011 S. Karger AG, Basel.

The Right to Development: Construction of a Non-Agriculturalist Discourse of Rurality in Denmark

ERIC Educational Resources Information Center

Svendsen, Gunnar Lind Haase

2004-01-01

The paper argues for the existence of two powerful discourses of rurality in Denmark after World War II. The first one is termed the modernist-agriculturalist discourse. Although still influential in the current public debate, in Denmark as well as in other Western European countries, this discourse of rurality had its heyday in the 1960s. It is…

Apprentice or Student? The Structures of Construction Industry Vocational Education and Training in Denmark and Sweden and Their Possible Consequences for Safety Learning

ERIC Educational Resources Information Center

Grytnes, Regine; Grill, Martin; Pousette, Anders; Törner, Marianne; Nielsen, Kent J.

2018-01-01

There is a notable difference in occupational injury rates in the two Scandinavian countries, Sweden and Denmark, with the latter having a 40% higher rate of fatal occupational injuries in the construction industry. This study explored differences in the vocational education and training (VET) systems between Sweden and Denmark that may be…

Draft Genome Sequence of the Psychrophilic and Alkaliphilic Rhodonellum psychrophilum Strain GCM71T.

PubMed

Hauptmann, Aviaja L; Glaring, Mikkel A; Hallin, Peter F; Priemé, Anders; Stougaard, Peter

2013-12-05

Rhodonellum psychrophilum GCM71(T), isolated from the cold and alkaline submarine ikaite columns in the Ikka Fjord in Greenland, displays optimal growth at 5 to 10°C and pH 10. Here, we report the draft genome sequence of this strain, which may provide insight into the mechanisms of adaptation to these extreme conditions.

50 CFR Table 47a to Part 679 - Percent of the AFA Catcher/Processor Sector's Pollock Allocation, Numbers of Chinook Salmon Used...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 371 1.65 Arctic Fjord 940866 3396 4.46 293 68 361 1.60 Northern Glacier 663457 661 3.12 205 48 253 1.12 Pacific Glacier 933627 3357 5.06 332 77 409 1.82 Highland Light 577044 3348 5.14 337 79 416 1.85...

50 CFR Table 47a to Part 679 - Percent of the AFA Catcher/Processor Sector's Pollock Allocation, Numbers of Chinook Salmon Used...

Code of Federal Regulations, 2012 CFR

2012-10-01

... 371 1.65 Arctic Fjord 940866 3396 4.46 293 68 361 1.60 Northern Glacier 663457 661 3.12 205 48 253 1.12 Pacific Glacier 933627 3357 5.06 332 77 409 1.82 Highland Light 577044 3348 5.14 337 79 416 1.85...

50 CFR Table 47a to Part 679 - Percent of the AFA Catcher/Processor Sector's Pollock Allocation, Numbers of Chinook Salmon Used...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 371 1.65 Arctic Fjord 940866 3396 4.46 293 68 361 1.60 Northern Glacier 663457 661 3.12 205 48 253 1.12 Pacific Glacier 933627 3357 5.06 332 77 409 1.82 Highland Light 577044 3348 5.14 337 79 416 1.85...

The annual planktonic protist community structure in an ice-free high Arctic fjord (Adventfjorden, West Spitsbergen)

NASA Astrophysics Data System (ADS)

Kubiszyn, A. M.; Wiktor, J. M.; Wiktor, J. M.; Griffiths, C.; Kristiansen, S.; Gabrielsen, T. M.

2017-05-01

We investigated the size and trophic structure of the annual planktonic protist community structure in the ice-free Adventfjorden in relation to environmental factors. Our high-resolution (weekly to monthly) study was conducted in 2012, when warm Atlantic water was advected into the fjord in winter and summer. We observed a distinct seasonality in the protist communities. The winter protist community was characterised by extremely low levels of protist abundance and biomass (primarily Dinophyceae, Ciliophora and Bacillariophyceae) in a homogenous water column. In the second half of April, the total protist abundance and biomass rapidly increased, thus initiating the spring bloom in a still well-mixed water column. The spring bloom was initially dominated by the prymnesiophyte Phaeocystis pouchetii and Bacillariophyceae (primarily from the genera Thalassiosira, Fragilariopsis and Chaetoceros) and was later strictly dominated by Phaeocystis colonies. When the bloom terminated in mid-June, the community shifted towards flagellates (Dinophyceae, Ciliophora, Cryptophyceae and nanoflagellates 3-7 μm in size) in a stratified, nutrient-depleted water column. Decreases in the light intensity decreased the protist abundance and biomass, and the fall community (Dinophyceae, Cryptophyceae and Bacillariophyceae) was followed by the winter community.

Seasonal dynamics of meroplankton in a high-latitude fjord

NASA Astrophysics Data System (ADS)

Michelsen, Helena Kling; Svensen, Camilla; Reigstad, Marit; Nilssen, Einar Magnus; Pedersen, Torstein

2017-04-01

Knowledge on the seasonal timing and composition of pelagic larvae of many benthic invertebrates, referred to as meroplankton, is limited for high-latitude fjords and coastal areas. We investigated the seasonal dynamics of meroplankton in the sub-Arctic Porsangerfjord (70°N), Norway, by examining their seasonal changes in relation to temperature, chlorophyll a and salinity. Samples were collected at two stations between February 2013 and August 2014. We identified 41 meroplanktonic taxa belonging to eight phyla. Multivariate analysis indicated different meroplankton compositions in winter, spring, early summer and late summer. More larvae appeared during spring and summer, forming two peaks in meroplankton abundance. The spring peak was dominated by cirripede nauplii, and late summer peak was dominated by bivalve veligers. Moreover, spring meroplankton were the dominant component in the zooplankton community this season. In winter, low abundances and few meroplanktonic taxa were observed. Timing for a majority of meroplankton correlated with primary production and temperature. The presence of meroplankton in the water column through the whole year and at times dominant in the zooplankton community, suggests that they, in addition to being important for benthic recruitment, may play a role in the pelagic ecosystem as grazers on phytoplankton and as prey for other organisms.

Top-down and bottom-up control on bacterial diversity in a western Norwegian deep-silled fjord.

PubMed

Storesund, Julia E; Erga, Svein Rune; Ray, Jessica L; Thingstad, T Frede; Sandaa, Ruth-Anne

2015-07-01

We investigated the relationship between viruses and co-occurring bacterial communities in the Sognefjord, a deep-silled fjord in Western Norway. A combination of flow cytometry and automated ribosomal intergenic spacer analysis (ARISA) was used to assess prokaryote and viral abundances, and bacterial diversity and community composition, respectively, in depth profiles and at two different sampling seasons (November and May). With one exception, bacterial diversity did not vary between samples regardless of depth or season. The virus and prokaryote abundances as well as bacterial community composition, however, varied significantly with season and depth, suggesting a link between the Sognefjord viral community and potential bacterial host community diversity. To our knowledge, these findings provide the first description of microbial communities in the unique Sognefjord ecosystem, and in addition are in agreement with the simple model version of the 'Killing the Winner' theory (KtW), which postulates that microbial community diversity is a feature that is essentially top-down controlled by viruses, while community composition is bottom-up controlled by competition for limiting growth substrates. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Spatio-temporal dynamics of species richness in coastal fish communities

USGS Publications Warehouse

Lekve, K.; Boulinier, T.; Stenseth, N.C.; Gjøsaeter, J.; Fromentin, J-M.; Hines, J.E.; Nichols, J.D.

2002-01-01

Determining patterns of change in species richness and the processes underlying the dynamics of biodiversity are of key interest within the field of ecology, but few studies have investigated the dynamics of vertebrate communities at a decadal temporal scale. Here, we report findings on the spado-temporal variability in the richness and composition of fish communities along the Norwegian Skagerrak coast having been surveyed for more than half a century. Using statistical models incorporating non-detection and associated sampling variance, we estimate local species richness and changes in species composition allowing us to compute temporal variability in species richness. We tested whether temporal variation could be related to distance to the open sea and to local levels of pollution. Clear differences in mean species richness and temporal variability are observed between fjords that were and were not exposed to the effects of pollution. Altogether this indicates that the fjord is an appropriate scale for studying changes in coastal fish communities in space and time. The year-to-year rates of local extinction and turnover were found to be smaller than spatial differences in community composition. At the regional level, exposure to the open sea plays a homogenizing role, possibly due to coastal currents and advection.

Streptomyces artemisiae MCCB 248 isolated from Arctic fjord sediments has unique PKS and NRPS biosynthetic genes and produces potential new anticancer natural products.

PubMed

Dhaneesha, M; Benjamin Naman, C; Krishnan, K P; Sinha, Rupesh Kumar; Jayesh, P; Joseph, Valsamma; Bright Singh, I S; Gerwick, William H; Sajeevan, T P

2017-05-01

After screening marine actinomycetes isolated from sediment samples collected from the Arctic fjord Kongsfjorden for potential anticancer activity, an isolate identified as Streptomyces artemisiae MCCB 248 exhibited promising results against the NCI-H460 human lung cancer cell line. H460 cells treated with the ethyl acetate extract of strain MCCB 248 and stained with Hoechst 33342 showed clear signs of apoptosis, including shrinkage of the cell nucleus, DNA fragmentation and chromatin condensation. Further to this treated cells showed indications of early apoptotic cell death, including a significant proportion of Annexin V positive staining and evidence of DNA damage as observed in the TUNEL assay. Amplified PKS 1 and NRPS genes involved in secondary metabolite production showed only 82% similarity to known biosynthetic genes of Streptomyces, indicating the likely production of a novel secondary metabolite in this extract. Additionally, chemical dereplication efforts using LC-MS/MS molecular networking suggested the presence of a series of undescribed tetraene polyols. Taken together, these results revealed that this Arctic S. artemisiae strain MCCB 248 is a promising candidate for natural products drug discovery and genome mining for potential anticancer agents.

Effect of oxygen minimum zone formation on communities of marine protists.

PubMed

Orsi, William; Song, Young C; Hallam, Steven; Edgcomb, Virginia

2012-08-01

Changes in ocean temperature and circulation patterns compounded by human activities are leading to oxygen minimum zone (OMZ) expansion with concomitant alteration in nutrient and climate active trace gas cycling. Here, we report the response of microbial eukaryote populations to seasonal changes in water column oxygen-deficiency using Saanich Inlet, a seasonally anoxic fjord on the coast of Vancouver Island British Columbia, as a model ecosystem. We combine small subunit ribosomal RNA gene sequencing approaches with multivariate statistical methods to reveal shifts in operational taxonomic units during successive stages of seasonal stratification and renewal. A meta-analysis is used to identify common and unique patterns of community composition between Saanich Inlet and the anoxic/sulfidic Cariaco Basin (Venezuela) and Framvaren Fjord (Norway) to show shared and unique responses of microbial eukaryotes to oxygen and sulfide in these three environments. Our analyses also reveal temporal fluctuations in rare populations of microbial eukaryotes, particularly anaerobic ciliates, that may be of significant importance to the biogeochemical cycling of methane in OMZs. Eukaryotic 18S rRNA gene sequences recovered from the Saanich Inlet water column on were deposited in Genbank under accession numbers HQ864863–HQ871151.

Marine fungi isolated from Chilean fjord sediments can degrade oxytetracycline.

PubMed

Ahumada-Rudolph, R; Novoa, V; Sáez, K; Martínez, M; Rudolph, A; Torres-Diaz, C; Becerra, J

2016-08-01

Salmon farming is the main economic activity in the fjords area of Southern Chile. This activity requires the use of antibiotics, such as oxytetracycline, for the control and prevention of diseases, which have a negative impact on the environment. We analyzed the abilities of endemic marine fungi to biodegrade oxytetracycline, an antibiotic used extensively in fish farming. We isolated marine fungi strains from sediment samples obtained from an area of fish farming activity. The five isolated strains showed an activity on oxytetracycline and were identified as Trichoderma harzianum, Trichoderma deliquescens, Penicillium crustosum, Rhodotorula mucilaginosa, and Talaromyces atroroseus by a scanning electron microscopy and characterized by molecular techniques. Results showed significant degradation in the concentration of oxytetracycline at the first 2 days of treatment for all strains analyzed. At 21 days of treatment, the concentration of oxytetracycline was decreased 92 % by T. harzianum, 85 % by T. deliquescens, 83 % by P. crustosum, 73 % by R. mucilaginosa, and 72 % by T. atroroseus, all of which were significantly higher than the controls. Given these results, we propose that fungal strains isolated from marine sediments may be useful tools for biodegradation of antibiotics, such as oxytetracycline, in the salmon industry.

Submarine melting from repeat UAV surveys of icebergs

NASA Astrophysics Data System (ADS)

Hubbard, A., II; Ryan, J.; Smith, L. C.; Hamilton, G. S.

2017-12-01

Greenland's tidewater glaciers are a primary contributor to global sea-level rise, yet their future trajectory remains uncertain due to their non-linear response to oceanic forcing: particularly with respect to rapid submarine melting and under-cutting of their calving fronts. To improve understanding of ice-ocean interactions, we conducted repeat unmanned aerial vehicle (UAV) surveys across the terminus of Store Glacier and its adjacent fjord between May and June 2014. The derived imagery provides insight into frontal plume dynamics and the changing freeboard volume of icebergs in the fjord as they ablate. Following the methodology of Enderlin and Hamilton (2014), by differencing iceberg freeboard volume, we constrain submarine melt rates adjacent to the calving front. We find that plume and submarine melt rates are critical to mass loss variability across the calving front. Although the frontal ablation of Store Glacier is dominated by large mechanical calving events, the undercutting induced by the meltwater plume increases the frequency of calving and initiates frontal retreat. We conclude that even small increases in submarine melting due to changes in the meltwater plume duration and/or circulation patterns can have important consequences for frontal mass loss from large outlet glaciers draining the Greenland ice sheet.

[Multiresistant tuberculosis in Denmark 1993-1996].

PubMed

Viskum, K; Kok-Jensen, A

1998-05-18

Infections with multiresistant tubercle bacilli have also become a problem in the rich part of the world. The reasons are lack of compliance in patients with life style problems and ineffectiveness of the health system due to lack of fundings. During a four year period, 1993-1996 ten patients were seen in Denmark with tuberculosis due to multiresistant Mycobacterium tuberculosis. Nine were infected abroad, one developed MDR-TB during treatment in Denmark. It is possible to cure these patients, but it is expensive and takes a long time. In the future more cases created within Denmark are likely to be seen due to lack of funding for the tuberculosis programme and, depending on immigration, further cases created abroad are expected.

Odense Pharmacoepidemiological Database: A Review of Use and Content.

PubMed

Hallas, Jesper; Hellfritzsch, Maja; Rix, Morten; Olesen, Morten; Reilev, Mette; Pottegård, Anton

2017-05-01

The Odense University Pharmacoepidemiological Database (OPED) is a prescription database established in 1990 by the University of Southern Denmark, covering reimbursed prescriptions from the county of Funen in Denmark and the region of Southern Denmark (1.2 million inhabitants). It is still active and thereby has more than 25 years of continuous coverage. In this MiniReview, we review its history, content, quality, coverage, governance and some of its uses. OPED's data include the Danish Civil Registration Number (CPR), which enables unambiguous linkage with virtually all other health-related registers in Denmark. Among its research uses, we review record linkage studies of drug effects, advanced drug utilization studies, some examples of method development and use of OPED as sampling frame to recruit patients for field studies or clinical trials. With the advent of other, more comprehensive sources of prescription data in Denmark, OPED may still play a role as in certain data-intensive regional studies. © 2017 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

The tragedy of becoming tired of living: Youth and young adults' suicide in Greenland and Denmark.

PubMed

Bolliger, Larissa; Gulis, Gabriel

2018-06-01

Suicide is a tremendous public health issue and worldwide the second leading cause of death among young people. In 2015, Greenland had the highest burden of disease due to self-harm with loss of 2,952.97 disability-adjusted life years per 100,000 inhabitants, more than six times as many as Denmark. What are possible reasons for Greenland's higher youth suicide rate compared to Denmark, despite being one kingdom of Denmark? Mixed methods in the form of qualitative, semi-structured interviews, the analysis of available data for 2003-2016 and a literature review were conducted with the aim to answer this question. Several exposures cause this difference, most significantly adverse effects of the colonial past, such as social issues and experienced traumas in Greenland compared to its former coloniser Denmark. The ongoing burden of youth suicide in Greenland requires enhanced actions of all stakeholders involved in suicide prevention, intervention and postvention.

Regionalization Lessons from Denmark.

PubMed

Vrangbaek, Karsten

2016-01-01

Denmark is a small Northern European country with an extensive welfare state and a strong commitment to maintaining a universal healthcare system. Like the other countries in the Nordic region, Denmark has a long tradition of democratically governed local and regional governments with extensive responsibilities in organizing welfare state services. The Danish healthcare system has demonstrated an ability to increase productivity, while at the same time maintaining a high level of patient satisfaction. Ongoing reforms have contributed to these results, as well as a firm commitment to innovation and coordination. Regions and municipalities in Denmark are governed by directly elected democratic councils. The Danish case is thus an example of democratic decentralization, but within a framework of national coordination and fiscal control. In spite of the difference in size and historical traditions there are also many similarities between Canada and Denmark, particularly in terms of health and social policy goals and aspirations, and in terms of the commitment to a comprehensive, universal healthcare system. These similarities provide interesting opportunities for comparison.

Changes in private alcohol importation after alcohol tax reductions and import allowance increases in Denmark

PubMed Central

Grittner, Ulrike; Bloomfield, Kim

2010-01-01

AIMS This paper examines changes in alcohol import in Denmark between 2003 and 2006, after the excise tax on spirits in Denmark was lowered by 45% on October 1, 2003 and travellers’ allowances for alcohol import were increased on January1, 2004. Additionally, the paper seeks to develop a profile of alcohol importers and analyse the relation between the distance to the German border and import behaviour, as Germany is the main alcohol import country for Denmark. DATA Cross-sectional and panel data from Denmark, from 2003 to 2006, were analyzed. Samples were collected by telephone interviews, using random digit dialing. RESULTS While the percentage of people who imported alcohol fell over time, the amount of alcohol purchased rose for those who did import. Distance to the German border was inversely related to the likelihood of importing and the level of imported amounts. Heavy drinkers and those with higher incomes were more likely to import, and heavy drinkers imported higher amounts than moderate drinkers or abstainers. CONCLUSION Distance of residence from the German border, socio-economic status and drinking behaviour are related to private alcohol import in Denmark. Policy changes resulted in a shift to fewer people importing higher amounts of alcohol so that the overall import level did not change substantially. PMID:21532978

Glacial-marine sediments record ice-shelf retreat during the late Holocene in Beascochea Bay on the western margin of the Antarctic Peninsula

NASA Astrophysics Data System (ADS)

Hardin, L. A.; Wellner, J. S.

2010-12-01

Beascochea Bay has an overall rapid rate of sedimentation due to retreating fast-flowing ice, and thus contains high-resolution records of Antarctica’s glacial and climate history. Beascochea Bay is a 16 km long by 8 km wide bay located on the western margin of the Antarctica Peninsula, centered between Anvers Island and Renaud Island, but open to the Bellingshausen Sea. Currently, three tidewater glaciers draining the Bruce Plateau of Graham Land enter into the fjords of Beascochea Bay, releasing terrigenous sediments which have left a record of the fluctuations of the Antarctic Peninsula Ice Cap since the grounded ice decoupled from the seafloor after the last glacial maximum. These three glaciers have played a significant role in providing sediment to the main basin, allowing a detailed sediment facies analysis to be conducted from eight sediment cores which were collected during the austral summer of 2007. Pebbly silty clay sediment cores, along with 3.5 kHz seismic data and multibeam swath bathymetry data, are integrated to reconstruct a glacial retreat timeline for the middle to late Holocene, which can be compared to the recent retreat rates over the last century. Paleoenvironment of deposition is determined by mapping lateral facies changes from the side fjords (proximal) to the outer basin (distal), as each region records the transition from glacial-marine sediments to open-marine sediments. As the ice retreated from the outer basin to the inner basin, and most recently leaving the side fjords, each facies deposited can be age-constrained by radiocarbon, 210Pb, and 137Cs dating methods. A distinct 137Cs signal is readily seen in two kasten cores from a side fjord and the inner basin of Beascochea Bay. This dating method revealed an average sedimentation rate of 2.7 mm per year for approximately the last century, which is comparable to 210Pb rates obtained in other studies. Lithology variations in each sediment core record indications of ice-shelf influence in Beascochea Bay throughout the Holocene deglaciation. The distinctively laminated sub-ice shelf facies can be clearly seen in the x-rays of these cores, and can be easily distinguished from the poorly sorted glacial-marine facies and the greenish finer-grained facies deposited in open-marine conditions. A 14 m long sediment core taken from the outer basin of Beascochea Bay recovered the greatest length of sediment and dates back to the middle Holocene. X-rays of this core show a possible mid-Holocene retreat of the ice shelf followed by intermittent advance and retreat that precedes the most recent retreat. The inner basin of Beascochea Bay has been without an ice shelf for the last 200 years, based on the sedimentation rates of the last century projected downcore.

Draft Genome Sequence of the Psychrophilic and Alkaliphilic Rhodonellum psychrophilum Strain GCM71T

PubMed Central

Hauptmann, Aviaja L.; Glaring, Mikkel A.; Hallin, Peter F.; Priemé, Anders

2013-01-01

Rhodonellum psychrophilum GCM71T, isolated from the cold and alkaline submarine ikaite columns in the Ikka Fjord in Greenland, displays optimal growth at 5 to 10°C and pH 10. Here, we report the draft genome sequence of this strain, which may provide insight into the mechanisms of adaptation to these extreme conditions. PMID:24309741

Collaborating with the local community of Kullorsuaq, Greenland to obtain high-quality hydrographic measurements near Alison Glacier

NASA Astrophysics Data System (ADS)

Porter, D. F.; Turrin, M.; Tinto, K. J.; Giulivi, C. F.; Cochran, J. R.; Bell, R. E.

2014-12-01

Warming ocean waters around Greenland have been implicated, along with warmer air temperatures, in the rapid increase of melt of the tidewater glaciers that drain the ice sheet. Most available regional oceanographic measurements have been collected during the summer seasons and are concentrated near the largest and most accessible glaciers. In order to gain a more comprehensive picture of the changing environment around the entirety of Greenland, more fjords, especially in the north, must be sampled. In July 2014, we travelled to Kullorsuaq in Northwest Greenland in order to foster a partnership with the local community to obtain new hydrographic data from CTD casts near Alison Glacier (74.6N, 57W). The terminus of this glacier abruptly retreated 10 km between 2000 and 2006. Although adequate observations from that time period are unavailable, our recently collected temperature and salinity data suggests that the deep water near Alison is similar to the waters further south, where near-synchronous ocean warming and glacial acceleration has been documented. Over the course of two sampling days, a hand-operated winch from a small boat was used to make standard CTD casts in front of Alison Glacier. We find evidence of glacial and mélange melt and the signature of both Polar and Atlantic Water masses at depth. Along-fjord casts illustrate how the ocean waters are modified as they circulate in and out of the fjord and the interaction of this water with the melting glacial front. At 500m depths, ocean temperatures are about 3°C above the in-situ freezing point of seawater, suggesting a possible influence of warm ocean waters on the mass loss of Alison Glacier. Using NASA Operation IceBridge and satellite altimetry data, we relate our new hydrographic data to the observed recent changes in Alison Glacier. An additional important result is that this short field campaign uncovered the possibility of working with local Greenlandic communities to aid scientists in both environmental monitoring and scientific discovery. Plans are underway to collaborate with the same and other communities in Greenland to take additional oceanographic measurements throughout the year.

Linking recent observations of cyclic steps from fjords to outcropping stratigraphic products, British Columbia, Canada

NASA Astrophysics Data System (ADS)

Hubbard, S. M.; Coutts, D. S.; Covault, J. A.

2016-12-01

Repeated bathymetric surveys of fjord prodeltas in Western Canada track channel erosion and deposition, which is interpreted to result from upstream migrating cyclic steps. Cyclic steps are long-wave (the ratio of wavelength to height is >>1), upstream-migrating bedforms that develop as a result of repeated internal hydraulic jumps in an overriding turbidity current at lee-to-stoss slope breaks. An internal hydraulic jump is the result of a transition from subaqueous densimetric Froude supercritical to subcritical flow. As the supercritical bedforms migrate greater than 90% of the deposits are reworked, making morphology- and facies- based recognition challenging in the depositional record. The objectives of this work are to use predictions of remnant bedform geometry from repeat bathymetric surveys to recognize cyclic step deposits in the stratigraphic record. We compare fjord deposits to Late Cretaceous submarine channel strata of the Nanaimo Group at Gabriola Island, British Columbia. In the Squamish prodelta, sediment accumulation on the stoss side of cyclic steps and erosion on the lee side promotes their up-slope migration. Deposits are modified by overriding turbidity currents, resulting in sedimentary bodies 5-30 m long, 0.5-2 m thick and < 30 m wide. The Nanaimo Group comprises scour fills of similar scale composed of stratified sandstone, with laminated siltstone locally overlying basal erosion surfaces. Up-slope dipping backset stratification is widely observed; packages of 2-4 backset beds, each of which are up to 60 cm thick and up to 15 m long (along dip), commonly share composite basal erosion surfaces. Numerous scour fills are recognized over thin intervals (< 4m) along 100-200 m depositional dip, indicating limited aggradation and preservation potential for the bedforms. It is likely that cyclic steps are common in strata deposited on high gradient submarine slopes. Evidence for updip-migrating cyclic step deposits inform a revised interpretation of a high gradient channel setting dominated by supercritical flow in the Nanaimo Group. The outcrop perspective, tied to data from seafloor surveys, offers insights into the stratigraphy and preservation potential of these bedforms.

Late Holocene intensification of the westerly winds at the subantarctic Auckland Islands (51° S), New Zealand

NASA Astrophysics Data System (ADS)

Browne, Imogen M.; Moy, Christopher M.; Riesselman, Christina R.; Neil, Helen L.; Curtin, Lorelei G.; Gorman, Andrew R.; Wilson, Gary S.

2017-10-01

The Southern Hemisphere westerly winds (SHWWs) play a major role in controlling wind-driven upwelling of Circumpolar Deep Water (CDW) and outgassing of CO2 in the Southern Ocean, on interannual to glacial-interglacial timescales. Despite their significance in the global carbon cycle, our understanding of millennial- and centennial-scale changes in the strength and latitudinal position of the westerlies during the Holocene (especially since 5000 yr BP) is limited by a scarcity of palaeoclimate records from comparable latitudes. Here, we reconstruct middle to late Holocene SHWW variability using a fjord sediment core collected from the subantarctic Auckland Islands (51° S, 166° E), located in the modern centre of the westerly wind belt. Changes in drainage basin response to variability in the strength of the SHWW at this latitude are interpreted from downcore variations in magnetic susceptibility (MS) and bulk organic δ13C and atomic C / N, which monitor influxes of lithogenous and terrestrial vs. marine organic matter, respectively. The fjord water column response to SHWW variability is evaluated using benthic foraminifer δ18O and δ13C, both of which are influenced by the isotopic composition of shelf water masses entering the fjord. Using these data, we provide marine and terrestrial-based evidence for increased wind strength from ˜ 1600 to 900 yr BP at subantarctic latitudes that is broadly consistent with previous studies of climate-driven vegetation change at the Auckland Islands. Comparison with a SHWW reconstruction using similar proxies from Fiordland suggests a northward migration of the SHWW over New Zealand during the first half of the last millennium. Comparison with palaeoclimate and palaeoceanographic records from southern South America and West Antarctica indicates a late Holocene strengthening of the SHWW after ˜ 1600 yr BP that appears to be broadly symmetrical across the Pacific Basin. Contemporaneous increases in SHWW at localities on either side of the Pacific in the late Holocene are likely controlled atmospheric teleconnections between the low and high latitudes, and by variability in the Southern Annular Mode and El Niño-Southern Oscillation.

Prevalence of neovascular age-related macular degeneration and geographic atrophy in Denmark.

PubMed

Sedeh, Farnam Barati; Scott, Daniel Andrew Richard; Subhi, Yousif; Sørensen, Torben Lykke

2017-11-01

In Denmark, age-related macular degeneration (AMD) is the most common cause of blindness. To better understand current and future challenges, we estimated and projected the annual number of patients with neovascular AMD and geographic atrophy in Denmark from 2016 to 2060. Detailed age- and gender-stratified prevalence estimates of neovascular AMD and geographic atrophy in a Scandinavian population were identified and applied to age- and gender-stratified population numbers provided by Statistics Denmark. Prevalence estimates were calculated for each year from 2016 to 2060. Future forecasts were provided by Statistics Denmark and based on calculations by the Danish Institute for Economic Modelling and Forecasting. We estimated that there are currently ~30,000 patients with neovascular AMD and ~21,000 patients with geographic atrophy in Denmark. The majority of these patients are persons aged ≥ 85 years. For neovascular AMD, the number of patients will grow to ~33,000 in 2020, ~58,000 in 2040 and ~72,000 in 2060. For geographic atrophy, the number of patients will grow to ~23,000 in 2020, ~41,000 in 2040, and ~50,000 in 2060. We expect a steady growth in the prevalence of neovascular AMD and geographic atrophy in Denmark due to an ageing population. These numbers emphasise the importance of disease prevention, careful planning of health service activities and continuing research. none. not relevant. Articles published in the DMJ are “open access”. This means that the articles are distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits any non-commercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Global War Game: Second Series, 1984-1988

DTIC Science & Technology

2004-08-01

Poland Netherlands Belgium Luxembourg 14°6° 48° 52° R hine Schleswig- Holstein Kiel Canal Denmark E lbe Elbe W eser Bremerhaven Frankfurt Fulda...consolidation continued on D+11, and two Polish armies pushed into Schleswig- Holstein , cutting off Denmark from the rest of NATO. The Warsaw Pact offensive...Switzerland Liechtenstein Italy Austria Czech Republic Poland Netherlands Belgium Luxembourg 14°6° 48° 52° R hine Schleswig- Holstein Kiel Canal Denmark FRG

Learning From Iraq: A Final Report From the Special Inspector General for Iraq Reconstruction

DTIC Science & Technology

2013-03-01

organizations that benefit Iraqi refugees, internally displaced persons, and other conflict victims; funding is also pro - vided to non-governmental...corrupt countries in the world. 0 2 4 6 8 10 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Finland Finland Iceland Finland Iceland New Zealand Denmark... Finland New Zealand Denmark New Zealand Sweden New ZealandNew Zealand Denmark New Zealand Singapore (113) (129) (137) (160) (133) Bangladesh (145

26 CFR 521.101 - Introductory.

Code of Federal Regulations, 2012 CFR

2012-04-01

... DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish... property (including rentals and like payments in respect of motion picture films) derived from sources...

26 CFR 521.101 - Introductory.

Code of Federal Regulations, 2011 CFR

2011-04-01

... DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish... property (including rentals and like payments in respect of motion picture films) derived from sources...

26 CFR 521.101 - Introductory.

Code of Federal Regulations, 2014 CFR

2014-04-01

... DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish... property (including rentals and like payments in respect of motion picture films) derived from sources...

26 CFR 521.101 - Introductory.

Code of Federal Regulations, 2013 CFR

2013-04-01

... DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish... property (including rentals and like payments in respect of motion picture films) derived from sources...

Public health research in Denmark in the years 1995--2005.

PubMed

Gulis, G; Eriksen, M L; Aro, A R

2010-02-01

The objective of this study was to find out the number of publications (in Danish) and research projects (including grey literature) either carried out or ongoing within the field of public health in Denmark, using the same criteria as the SPHERE project, but looking at Danish research databases. The Danish research database served as the main resource for the study supported by national research reports. There is an increasing trend in the number of public health research projects and publications. Compared with public health research projects published in English there are differences in some categories. Overall, public health research in Denmark seems to contribute around 4.8%-6.5% of the total amount of health research. Public health research has a relatively low share of overall health research in Denmark.

Energy and Resources

ERIC Educational Resources Information Center

Sorensen, Bent

1975-01-01

Discusses the feasibility of utilizing continuous sources of of energy, particularly solar and wind energy. Outlines an energy plan for Denmark, which would supply all of Denmark's energy needs by the year 2050. (MLH)

2 CFR 176.90 - Non-application to acquisitions covered under international agreements.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., Bulgaria, Canada, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hong Kong..., Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg...

Alacrymie congénitale révélant un syndrome d'Allgrove: à propos de trois cas

PubMed Central

Derrar, Rajae; Boutimzine, Nourredinne; Laghmari, Amina; Alouane, Amal; Daoudi, Rajae

2015-01-01

Le syndrome d'Allgrove ou triple A syndrome est une affection autosomique récessive constatée chez la population pédiatrique, associant dans sa forme complète: Achalasie œsophagienne, Alacrymie, maladie d'Addison (insuffisance surrénale), une dégénérescence neurologique et occasionnellement une instabilité du système autonome. Nous rapportons les cas de 3 enfants issus de mariages consanguins, chez qui l'examen ophtalmologique a révélé une sécheresse sévère avec dans deux cas une kératite envahissant l'axe visuel, ainsi qu'une paresse du reflexe photomoteur. Le bilan radiologique: transit œsogastroduodénal (TOGD) et fibroscopie œsogastroduodénale (FOGD) a révélé un mégaoesophage associé dans un cas à une œsophagite. Un traitement à base de larmes artificielles est instauré aussitôt, ainsi qu'un traitement chirurgical par voie laparoscopique. La connaissance de cette pathologie permettra une prise de conscience de la gravité de cette maladie en plus de suggérer sa prise en charge. PMID:26185551

[The importance of centralized treatment: research and development].

PubMed

Højgaard, Liselotte

2006-04-10

Biomedical research in Denmark enjoys a strong position at present but will be challenged by a new organization for all hospitals in Denmark beginning in 2007. It will be very important to recognize the importance of medical research as the cornerstone of optimal patient treatment in the new hospital organizations. Centralization with a focus on efficiency and low cost, as well as decentralization combined with the loss of university hospital functions, will further challenge the conditions of clinical research already seen worldwide and also experienced in Denmark.

Metamorphosed ultramafic rocks in east Greenland

NASA Technical Reports Server (NTRS)

Kays, M. A.; Dorais, M. J.

1986-01-01

The compositional and mineralogical characteristics of Archean ultramafic rocks in Kangerdlugssuaq Fjord are summarized: the first provides information important to understanding the primary character of the rock suite, whereas the latter provides data necessary to determine the conditions of their equilibrium during the latest metamorphism. This information will be of value in determining the affinity of the suite to similar Archean rocks in other areas of the North Atlantic craton.

Copper Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Review.

DTIC Science & Technology

1998-01-01

species; Brazil; November 1989; whole Alga, Ascophyllum nodosum England; polluted bay vs. reference site Norway; polluted fjord vs. reference site...concentra- tions of copper are sometimes fatal to ducklings (Wood and Worden 1973) and livestock when fed for extended periods. Domestic sheep ...is widely used in veterinary clinics in medical products (Roncero et al. 1992). Copper sulfate is used by veterinarians to treat cattle and sheep

Ice Island Calves off Petermann Glacier

NASA Image and Video Library

2017-12-08

NASA image acquired August 11, 2010. After breaking off the Petermann Glacier on August 5, 2010, a massive ice island floated slowly down the fjord toward the Nares Strait. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite captured this false-color image of the ice island on August 11, 2010. In this image, ice is light blue, water is nearly black, and clouds are nearly white. Although a bank of thin clouds hovers over the fjord, the southernmost margin of the ice island is still visible. Toward the north, the leading edge of the ice island retains the same shape it had days earlier, at the time of the initial calving. NASA Earth Observatory image created by Jesse Allen, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Caption by Michon Scott. Instrument: Terra - ASTER To see more images from of the glacier go to: earthobservatory.nasa.gov/NaturalHazards/event.php?id=45116 NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Response of marine benthic fauna to thin-layer capping with activated carbon in a large-scale field experiment in the Grenland fjords, Norway.

PubMed

Samuelsson, Göran S; Raymond, Caroline; Agrenius, Stefan; Schaanning, Morten; Cornelissen, Gerard; Gunnarsson, Jonas S

2017-06-01

A field experiment with thin-layer capping was conducted in the Grenland fjords, Norway, for remediation in situ of mercury and dioxin-contaminated sediments. Experimental fields at 30 and 95 m depth were capped with (i) powdered activated carbon (AC) mixed with clay (AC+cla`y), (ii) clay, and (iii) crushed limestone. Ecological effects on the benthic community and species-feeding guilds were studied 1 and 14 months after capping, and a total of 158 species were included in the analyses. The results show that clay and limestone had only minor effects on the benthic community, while AC+clay caused severe perturbations. AC+clay reduced the abundance, biomass, and number of species by up to 90% at both 30 and 95 m depth, and few indications of recovery were found during the period of this investigation. The negative effects of AC+clay were observed on a wide range of species with different feeding strategies, although the suspension feeding brittle star Amphiura filiformis was particularly affected. Even though activated carbon is effective in reducing sediment-to-water fluxes of dioxins and other organic pollutants, this study shows that capping with powdered AC can lead to substantial disturbances to the benthic community.

Accessing the inaccessible: making (successful) field observations at tidewater glacier termini

NASA Astrophysics Data System (ADS)

Kienholz, C.; Amundson, J. M.; Jackson, R. H.; Motyka, R. J.; Nash, J. D.; Sutherland, D.

2017-12-01

Glaciers terminating in ocean water (tidewater glaciers) show complex dynamic behavior driven predominantly by processes at the ice-ocean interface (sedimentation, erosion, iceberg calving, submarine melting). A quantitative understanding of these processes is required, for example, to better assess tidewater glaciers' fate in our rapidly warming environment. Lacking observations close to glacier termini, due to unpredictable risks from calving, hamper this understanding. In an effort to remedy this lack of knowledge, we initiated a large field-based effort at LeConte Glacier, southeast Alaska, in 2016. LeConte Glacier is a regional analog for many tidewater glaciers, but better accessible and observable and thus an ideal target for our multi-disciplinary effort. Our ongoing campaigns comprise measurements from novel autonomous vessels (temperature, salinity and current) in the immediate proximity of the glacier terminus and additional surveys (including multibeam bathymetry) from boats and moorings in the proglacial fjord. These measurements are complemented by iceberg and glacier velocity measurements from time lapse cameras and a portable radar interferometer situated above LeConte Bay. GPS-based velocity observations and melt measurements are conducted on the glacier. These measurements provide necessary input for process-based understanding and numerical modeling of the glacier and fjord systems. In the presentation, we discuss promising initial results and lessons learned from the campaign.

Strong Seasonality of Marine Microbial Eukaryotes in a High-Arctic Fjord (Isfjorden, in West Spitsbergen, Norway)

PubMed Central

Vader, Anna; Stübner, Eike I.; Reigstad, Marit

2016-01-01

The Adventfjorden time series station (IsA) in Isfjorden, West Spitsbergen, Norway, was sampled frequently from December 2011 to December 2012. The community composition of microbial eukaryotes (size, 0.45 to 10 μm) from a depth of 25 m was determined using 454 sequencing of the 18S V4 region amplified from both DNA and RNA. The compositional changes throughout the year were assessed in relation to in situ fjord environmental conditions. Size fractionation analyses of chlorophyll a showed that the photosynthetic biomass was dominated by small cells (<10 μm) most of the year but that larger cells dominated during the spring and summer. The winter and early-spring communities were more diverse than the spring and summer/autumn communities. Dinophyceae were predominant throughout the year. The Arctic Micromonas ecotype was abundant mostly in the early-bloom and fall periods, whereas heterotrophs, such as marine stramenopiles (MASTs), Picozoa, and the parasitoid marine alveolates (MALVs), displayed higher relative abundance in the winter than in other seasons. Our results emphasize the extreme seasonality of Arctic microbial eukaryotic communities driven by the light regime and nutrient availability but point to the necessity of a thorough knowledge of hydrography for full understanding of their succession and variability. PMID:26746718

Microbial Diversity in a Permanently Cold and Alkaline Environment in Greenland

PubMed Central

Glaring, Mikkel A.; Vester, Jan K.; Lylloff, Jeanette E.; Abu Al-Soud, Waleed; Sørensen, Søren J.; Stougaard, Peter

2015-01-01

The submarine ikaite columns located in the Ikka Fjord in Southern Greenland represent a unique, permanently cold (less than 6°C) and alkaline (above pH 10) environment and are home to a microbial community adapted to these extreme conditions. The bacterial and archaeal community inhabiting the ikaite columns and surrounding fjord was characterised by high-throughput pyrosequencing of 16S rRNA genes. Analysis of the ikaite community structure revealed the presence of a diverse bacterial community, both in the column interior and at the surface, and very few archaea. A clear difference in overall taxonomic composition was observed between column interior and surface. Whereas the surface, and in particular newly formed ikaite material, was primarily dominated by Cyanobacteria and phototrophic Proteobacteria, the column interior was dominated by Proteobacteria and putative anaerobic representatives of the Firmicutes and Bacteroidetes. The results suggest a stratification of the ikaite columns similar to that of classical soda lakes, with a light-exposed surface inhabited by primary producers and an anoxic subsurface. This was further supported by identification of major taxonomic groups with close relatives in soda lake environments, including members of the genera Rhodobaca, Dethiobacter, Thioalkalivibrio and Tindallia, as well as very abundant groups related to uncharacterised environmental sequences originally isolated from Mono Lake in California. PMID:25915866

Microbial diversity in a permanently cold and alkaline environment in Greenland.

PubMed

Glaring, Mikkel A; Vester, Jan K; Lylloff, Jeanette E; Al-Soud, Waleed Abu; Sørensen, Søren J; Stougaard, Peter

2015-01-01

The submarine ikaite columns located in the Ikka Fjord in Southern Greenland represent a unique, permanently cold (less than 6°C) and alkaline (above pH 10) environment and are home to a microbial community adapted to these extreme conditions. The bacterial and archaeal community inhabiting the ikaite columns and surrounding fjord was characterised by high-throughput pyrosequencing of 16S rRNA genes. Analysis of the ikaite community structure revealed the presence of a diverse bacterial community, both in the column interior and at the surface, and very few archaea. A clear difference in overall taxonomic composition was observed between column interior and surface. Whereas the surface, and in particular newly formed ikaite material, was primarily dominated by Cyanobacteria and phototrophic Proteobacteria, the column interior was dominated by Proteobacteria and putative anaerobic representatives of the Firmicutes and Bacteroidetes. The results suggest a stratification of the ikaite columns similar to that of classical soda lakes, with a light-exposed surface inhabited by primary producers and an anoxic subsurface. This was further supported by identification of major taxonomic groups with close relatives in soda lake environments, including members of the genera Rhodobaca, Dethiobacter, Thioalkalivibrio and Tindallia, as well as very abundant groups related to uncharacterised environmental sequences originally isolated from Mono Lake in California.

Subsurface iceberg melt key to Greenland fjord freshwater budget

NASA Astrophysics Data System (ADS)

Moon, T.; Sutherland, D. A.; Carroll, D.; Felikson, D.; Kehrl, L.; Straneo, F.

2018-01-01

Liquid freshwater fluxes from the Greenland ice sheet affect ocean water properties and circulation on local, regional and basin-wide scales, with associated biosphere effects. The exact impact, however, depends on the volume, timing and location of freshwater releases, which are poorly known. In particular, the transformation of icebergs, which make up roughly 30-50% of the loss of the ice-sheet mass to liquid freshwater, is not well understood. Here we estimate the spatial and temporal distribution of the freshwater flux for the Helheim-Sermilik glacier-fjord system in southeast Greenland using an iceberg-melt model that resolves the subsurface iceberg melt. By estimating seasonal variations in all the freshwater sources, we confirm quantitatively that iceberg melt is the largest annual freshwater source in this system type. We also show that 68-78% of the iceberg melt is released below a depth of 20 m and, seasonally, about 40-100% of that melt is likely to remain at depth, in contrast with the usual model assumptions. Iceberg melt also peaks two months after all the other freshwater sources peak. Our methods provide a framework to assess individual freshwater sources in any tidewater system, and our results are particularly applicable to coastal regions with a high solid-ice discharge in Greenland.

The Southern Andes of South America as seen from STS-60

NASA Image and Video Library

1994-02-09

STS060-85-000AH (3-11 Feb 1994) --- This view is centered at about 44 degrees south along the Chilean continental margin of South America. The dark-colored coastal region is heavily forested by dense old-growth forests that are now being cut, but east of the mountains in Argentina the dry climate supports very little vegetation. This desert region known as Patagonia appears as light brown colors. The coastline is especially dramatic because it is shaped by the tortuous channels carved by glaciers which have left fjords. These fjords have effectively cut across the continental divide, and are bordered by active volcanoes which reach elevations between 2, 000 - 3,000 meters. The prominent volcanic peak in the center of the frame is Mt. Melimoya. To the north is a long, snow-covered volcanic ridge called Cerro Yantales. Cerro Yantales recently reported greatly increased fumarolic activity, including the emission of yellow gases near the summit. Russian and American scientists will use this photography to look for further evidence of increased activity like snow melt around the peak. Other Russian and American scientists are particularly interested in mapping the summertime snowline and firm (permanent snow field) elevations as early indications of any potential climatic variation in the making.

Ecotoxicological sediment evaluations in marine aquaculture areas of Chile.

PubMed

Rudolph, Anny; Medina, Paulina; Urrutia, Carolina; Ahumada, Ramón

2009-08-01

Given its geographic characteristics, the southern Chilean fjord area is subjected to growing environmental pressure from the development of diverse forms of aquaculture (i.e., fish, algae, shellfish). The sediments accumulate substances as a natural sink, and ecotoxicology assays offer a reliable and robust proxy for sediment quality analyses. This study's objective was to establish a mid-range toxicity base line for the sediments in the region by applying a battery of non-specific ecotoxicological assays. Sediment samples (28) were collected in the channels and fjords studied during the CIMAR-Fiordos 11 cruise (July 2005). The sediments were evaluated using different species endemic to the eastern Pacific as targets: Ampelisca araucana, Tisbe longicornis, Arbacia spatuligera, and Dunaliella tertiolecta. The conditions for each assay were reported previously. Of the four species used as ecotoxicological tools, only D. tertiolecta differed significantly from the control group (negative) in terms of its growth. This difference could be attributed to nutrient enrichment. In general, we concluded that, although local changes occurred in the sediments, the mesoscale magnitude of the ecotoxicological alterations was small. Nonetheless, a surveillance program should be implemented that would allow us to follow-up and analyze the changes that are taking place in the systems on broader scales of time and space.

Play Spaces in Denmark.

ERIC Educational Resources Information Center

Mitchell, Edna; Anderson, Robert T.

1980-01-01

Describes the variety of play spaces found in urban areas in Denmark: in banks, stores and individual businesses, neighborhood parks and small pocket playgrounds, specialized adventure and traffic playgrounds with supervised activities, and commercial amusement parks. (CM)

High-frequency fluctuations in Denmark Strait transport

NASA Astrophysics Data System (ADS)

Haine, T. W. N.

2010-07-01

Denmark Strait ocean current transport exhibits quasi-regular fluctuations immediately south of the sill with periods of 2-4 days. The transport variability is similar to the mean transport itself. Using a circulation model we explore prospects to monitor the fluctuations. The model has realistic transport and shows water leaving Denmark Strait in equivalent-barotropic cyclones that are nearly geostrophic and correlate with sea-surface height (SSH). Existing satellite altimeter observations of SSH have adequate space/time sampling to reconstruct the transport fluctuations using a regression developed from the model results, but measurement error overwhelms the signal. From the model results, the pending Surface Water and Ocean Topography (SWOT) wide-swath altimeter appears accurate enough, and with good-enough coverage, to allow the transport fluctuations to be reconstructed. Bottom pressure recorders at the exit of the Denmark Strait can also reproduce the transport variability.

[High levels of industrially produced trans fatty acids in popular fast food - but not in Denmark--secondary publication].

PubMed

Stender, Steen; Dyerberg, Jørn; Bysted, Anette; Leth, Torben; Astrup, Arne V

2006-04-24

An intake of trans-fatty acids of 5 grams per day is associated with an increase of 25% in the risk of ischemic heart disease. In 2004 Denmark, as the first country in the world, introduced a limitation on the content of industrially produced trans-fatty acids in foods. The amount in a "high-trans menu" consisting of popular foods was, from 2001 to 2005, reduced in Denmark from 30 g to <1 g. The amount in the same menu bought in countries within and outside the European Union is 20-40 g. During a period of just a few years, Denmark has thus eliminated a risk factor for ischemic heart disease without noticeable side effects for consumers. This risk factor is, however, still present in many other countries.

Marked differences in GPs' diagnosis of pneumonia between Denmark and Spain: a cross-sectional study.

PubMed

Christensen, Sarah Friis; Jørgensen, Lars Christian; Cordoba, Gloria; Llor, Carl; Siersma, Volkert; Bjerrum, Lars

2013-12-01

In patients with lower respiratory tract infections (LRTIs) it is a challenge to identify who should be treated with antibiotics. According to international guidelines, antibiotics should be prescribed to patients with suspected pneumonia while acute bronchitis is considered a viral infection and should, generally, not be treated with antibiotics. Overdiagnosis of pneumonia in patients with LRTIs may lead to antibiotic overprescribing. To investigate the prevalence of presumed pneumonia in patients with LRTI in two countries with different antibiotic prescribing rates (Denmark and Spain) and to compare which symptoms and clinical tests are of most importance for the GP when choosing a diagnosis of pneumonia rather than acute bronchitis. A cross-sectional study including GPs from Denmark and Spain was conducted as part of the EU-funded project HAPPY AUDIT. A total of 2,698 patients with LRTI were included. In Denmark, 47% of the patients with LRTI were classified with a diagnosis of pneumonia compared with 11% in Spain. In Spain, fever and a positive x-ray weighted significantly more in the diagnosis of pneumonia than in Denmark. Danish GPs, however, attached more importance to dyspnoea/polypnoea and C-reactive protein levels >50mg/L. None of the other typical symptoms of pneumonia had a significant influence. Our results indicate that GPs' diagnostic criteria for pneumonia differ substantially between Denmark and Spain. The high prevalence of pneumonia among Danish patients with LRTI may indicate overdiagnosis of pneumonia which, in turn, may lead to antibiotic overprescribing.

Profil épidémiologique des hémoglobinopathies: étude transversale descriptive autour du cas index

PubMed Central

Dahmani, Fatima; Benkirane, Souad; Kouzih, Jaafar; Woumki, Aziz; Mamad, Hassan; Masrar, Azlarab

2017-01-01

Les hémoglobinopathies sont des affections constitutionnelles conséquentes à des anomalies des hémoglobines. Elles sont souvent graves dans leurs formes majeures, leur prise en charge est lourde avec un grand impact psycho-social sur les patients et leur famille. Classées parmi les maladies rares, elles sont encore insuffisamment connues des professionnels de santé. Cette méconnaissance est à l'origine d'une errance diagnostique, d'un retard dans leur prise en charge et par conséquent une morbidité et une mortalité élevée chez ces patients. L'Organisation Mondiale de la Santé (OMS) a publié en 2008 des données concernant l'épidémiologie des hémoglobinopathies: plus de 330000 cas naissent chaque année avec une hémoglobinopathie (83% des cas de drépanocytose, 17% des cas de thalassémie). Les troubles de l'hémoglobine sont responsables d'environ 3,4% des décès chez les moins de 5 ans. A l'échelle mondiale, 7% environ des femmes enceintes seraient porteuses d'une forme de la thalassémie et 1% des couples sont à risque. Toutefois, elles sont relativement fréquentes dans certaines régions du globe où les mariages consanguins sont communs. Afin de décrire les caractéristiques épidémiologiques des familles à risque d'hémoglobinopathies (étude autour du cas) dont les cas index sont suivis au service de pédiatrie à l'Hôpital Provincial El Idrisi de Kenitra au Maroc, une étude transversale descriptive a été réalisée durant deux enquêtes la première en mai 2015 et la deuxième en juin de la même année lors des journées de vaccination des cas index contre le pneumocoque. Après avoir recueilli les données épidémiologiques de nos patients, nous avons réalisé une étude biologique comportant: l'hémogramme avec étude morphologique des globules rouges en coloration MGG et numération automatique des réticulocytes; les électrophorèses de l'hémoglobine à pH alcalin (8.8) et secondairement à pH acide (5.4) sur gel d'agarose avec intégration densitométrique. 275 patients ont présenté des profils compatibles à une hémoglobinopathie. La majorité de ces malades étaient issus de mariages consanguins (83.1%) et originaires de régions situées dans le nord du Maroc. L'enquête familiale a permis de retrouver les familles à risque, chez lesquelles on note une fréquence élevée de drépanocytose. Nos résultats confirment l'existence de différents types d'hémoglobinopathies dans la population marocaine. PMID:28904678

Le diagnostic anténatal de la trisomie 21 par l'hybridation in situ en fluorescence (FISH): à propos des premiers tests réalisés au Maroc

PubMed Central

Lamzouri, Afaf; Natiq, Abdelhafid; Tajir, Mariam; Sendid, Mohamed; Sefiani, Abdelaziz

2012-01-01

Introduction Le but de cette étude était de présenter les premiers résultats de diagnostic anténatal de la trisomie 21 par la technique d'hybridation in situ en fluorescence (FISH) au Maroc et discuter son intérêt dans le diagnostic rapide de cette aneuploïdie. Méthodes Ce travail a été réalisé chez 23 femmes avec des grossesses à haut risque de trisomie 21. La moyenne d’âge des gestantes étaient de 37,43 ans avec des extrêmes de 21 et 43 ans. Toutes étaient musulmanes mariées, mariage légitimé par la Charia, dont trois mariages consanguins, sauf une originaire de la République Démocratique du Congo qui était chrétienne et concubine. La majorité des femmes étaient fonctionnaires et avaient un niveau de scolarisation moyen à élevé. Toutes les patientes ont bénéficié d'une consultation de génétique médicale au cours de laquelle il leur a été donné des informations sur la technique, son intérêt et ses limites. Il s'agit de femmes enceintes qui avaient soit un âge maternel élevé ou des signes d'appel échographiques et/ ou biochimiques. Une des patientes était porteuse d'une translocation robertsonienne t(14;21) équilibrée. Une amniocentèse a été réalisée chez toutes les gestantes et aucun avortement n'a était induit par ce geste invasif. L’âge gestationnel moyen à la première consultation était de 14 semaines d'aménorrhée (SA) et à l'amniocentèse était de 16 SA et 5 jours. L'analyse FISH a été réalisée, après consentement des couples, sur des cellules non cultivées à partir des échantillons de liquides amniotiques, en utilisant des sondes spécifiques du chromosome 21. Résultats Parmi les 23 patientes qui ont bénéficiées d'un diagnostic anténatal de la trisomie 21 par la technique FISH, nous avons pu rassurer 21 d'entre elles, et nous avons détecté deux cas de trisomie 21 fœtal. Conclusion La technique FISH permet un diagnostic anténatal rapide, en moins de 48h, de la trisomie 21 sur une faible quantité de liquide amniotique. Elle offre aux couples l'avantage de prendre, dans des délais raisonnables, la décision qui leur convient concernant la poursuite ou non de la grossesse. Elle permet souvent, avec un résultat normal, de rassurer rapidement les femmes enceintes trop angoissées. PMID:23330029

Nationwide Genomic Study in Denmark Reveals Remarkable Population Homogeneity

PubMed Central

Athanasiadis, Georgios; Cheng, Jade Y.; Vilhjálmsson, Bjarni J.; Jørgensen, Frank G.; Als, Thomas D.; Le Hellard, Stephanie; Espeseth, Thomas; Sullivan, Patrick F.; Hultman, Christina M.; Kjærgaard, Peter C.; Schierup, Mikkel H.; Mailund, Thomas

2016-01-01

Denmark has played a substantial role in the history of Northern Europe. Through a nationwide scientific outreach initiative, we collected genetic and anthropometrical data from ∼800 high school students and used them to elucidate the genetic makeup of the Danish population, as well as to assess polygenic predictions of phenotypic traits in adolescents. We observed remarkable homogeneity across different geographic regions, although we could still detect weak signals of genetic structure reflecting the history of the country. Denmark presented genomic affinity with primarily neighboring countries with overall resemblance of decreasing weight from Britain, Sweden, Norway, Germany, and France. A Polish admixture signal was detected in Zealand and Funen, and our date estimates coincided with historical evidence of Wend settlements in the south of Denmark. We also observed considerably diverse demographic histories among Scandinavian countries, with Denmark having the smallest current effective population size compared to Norway and Sweden. Finally, we found that polygenic prediction of self-reported adolescent height in the population was remarkably accurate (R2 = 0.639 ± 0.015). The high homogeneity of the Danish population could render population structure a lesser concern for the upcoming large-scale gene-mapping studies in the country. PMID:27535931

Differing Procedures for Recording Mortality Statistics in Scandinavia.

PubMed

Tøllefsen, Ingvild M; Hem, Erlend; Ekeberg, Øivind; Zahl, Per-Henrik; Helweg-Larsen, Karin

2017-03-01

There may be various reasons for differences in suicide rates between countries and over time within a country. One reason can be different registration practices. The purpose of this study was to describe and compare the present procedures for mortality and suicide registration in the three Scandinavian countries and to illustrate potential sources of error in the registration of suicide. Information about registration practices and classification procedures was obtained from the cause of death registers in Norway, Sweden, and Denmark. In addition, we received information from experts in the field in each country. Sweden uses event of undetermined intent more frequently than Denmark does, and Denmark more frequently than Norway. There seems to be somewhat more uncertainty among deaths classified as ill-defined and unknown cause of mortality in Norway, compared with the other two countries. Sweden performs more forensic autopsies than Norway, and Norway more than Denmark. In Denmark, in cases of a suspected unnatural manner of death, a thorough external examination of the deceased is performed. Differences in the classification of causes of death and in postmortem examinations exist in Scandinavian countries. These differences might influence the suicide statistics in Scandinavia.

Energy balance and runoff modelling of glaciers in the Kongsfjord basin in northwestern Svalbard

NASA Astrophysics Data System (ADS)

Kohler, J.; Pramanik, A.; van Pelt, W.

2016-12-01

Glaciers and ice caps cover 36,000 Km2 or 60% of the land area of the Svalbard archipelago. Roughly 60% of the glaciated area drains to the ocean through tidewater glacier fronts. Runoff from tidewater glaciers is posited to have a significant impact on fjord circulation and thereby on fjord ecosystems. Ocean circulation modelling underway in the Kongsfjord system requires specification of the freshwater amounts contributed by both tidewater and land-terminating glaciers in its basin. The total basin area of Kongsfjord is 1850 km2. We use a coupled surface energy-balance and firn model (Van Pelt et al. 2015) to calculate mass balance and runoff from the Kongsfjord glaciers for the period 1969-2015. Meteorological data from the nearby station at Ny-Ålesund is used for climate forcing in the model domain, with mass balance data at four glaciers in the Kongsfjord watershed used to calibrate model parameters. Precipitation and temperature lapse rates are adjusted on the study glaciers through repeated model runs at mass balance stake locations to match observed and modelled surface mass balance. Long-term discharge measurement at two sites in this region are used to validate the modelled runoff. Spatial and temporal evolution of melt, refreezing and runoff are analyzed, along with the vertical evolution of subsurface conditions. Reference: Van Pelt, W.J.J. & J. Kohler. 2015. Modelling the long-term mass balance and firn evolution of glaciers around Kongsfjorden, Svalbard. J. Glaciol, 61(228), 731-744. Glaciers and ice caps cover 36,000 Km2 or 60% of the land area of the Svalbard archipelago. Roughly 60% of the glaciated area drains to the ocean through tidewater glacier fronts. Runoff from tidewater glaciers is posited to have a significant impact on fjord circulation and thereby on fjord ecosystems. Ocean circulation modelling underway in the Kongsfjord system requires specification of the freshwater amounts contributed by both tidewater and land-terminating glaciers in its basin. The total basin area of Kongsfjord is 1850 km2. We use a coupled surface energy-balance and firn model (Van Pelt et al. 2015) to calculate mass balance and runoff from the Kongsfjord glaciers for the period 1969-2015. Meteorological data from the nearby station at Ny-Ålesund is used for climate forcing in the model domain, with mass balance data at four glaciers in the Kongsfjord watershed used to calibrate model parameters. Precipitation and temperature lapse rates are adjusted on the study glaciers through repeated model runs at mass balance stake locations to match observed and modelled surface mass balance. Long-term discharge measurement at two sites in this region are used to validate the modelled runoff. Spatial and temporal evolution of melt, refreezing and runoff are analyzed, along with the vertical evolution of subsurface conditions. Reference: Van Pelt, W.J.J. & J. Kohler. 2015. Modelling the long-term mass balance and firn evolution of glaciers around Kongsfjorden, Svalbard. J. Glaciol, 61(228), 731-744.

[Iodine fortification of salt and thyroid disease in Denmark].

PubMed

Laurberg, Peter; Jørgensen, Torben; Ovesen, Lars; Rasmussen, Lone Banke; Perrild, Hans; Andersen, Stig; Carlé, Allan; Cerqueira, Charlotte; Knudsen, Nils; Pedersen, Inge Bülow; Vejberg, Pernille

2011-12-12

Until 2000 Denmark was iodine deficient with moderate deficiency in the western part and mild deficiency in the eastern part. The occurrence of goitre and autonomous hyperthyroidism was high, and pregnancy was associated with a reduction in thyroid function. After cautious mandatory iodization of household salt and salt used for bread production, the iodine intake in Denmark is now low normal. The DanThyr monitoring has shown a transient increase in hyperthyroidism followed by a decrease, and goitre is becoming less common. Hypothyroidism has become more common, and this has to be followed.

Scandinavian neuroscience during the Nazi era.

PubMed

Kondziella, Daniel; Hansen, Klaus; Zeidman, Lawrence A

2013-07-01

Although Scandinavian neuroscience has a proud history, its status during the Nazi era has been overlooked. In fact, prominent neuroscientists in German-occupied Denmark and Norway, as well as in neutral Sweden, were directly affected. Mogens Fog, Poul Thygesen (Denmark) and Haakon Sæthre (Norway) were resistance fighters, tortured by the Gestapo: Thygesen was imprisoned in concentration camps and Sæthre executed. Jan Jansen (Norway), another neuroscientist resistor, escaped to Sweden, returning under disguise to continue fighting. Fritz Buchthal (Denmark) was one of almost 8000 Jews escaping deportation by fleeing from Copenhagen to Sweden. In contrast, Carl Værnet (Denmark) became a collaborator, conducting inhuman experiments in Buchenwald concentration camp, and Herman Lundborg (Sweden) and Thorleif Østrem (Norway) advanced racial hygiene in order to maintain the "superior genetic pool of the Nordic race." Compared to other Nazi-occupied countries, there was a high ratio of resistance fighters to collaborators and victims among the neuroscientists in Scandinavia.

Awareness of cancer symptoms and anticipated patient interval for healthcare seeking. A comparative study of Denmark and Sweden.

PubMed

Hvidberg, Line; Lagerlund, Magdalena; Pedersen, Anette F; Hajdarevic, Senada; Tishelman, Carol; Vedsted, Peter

2016-07-01

Background Recent epidemiologic data show that Denmark has considerably poorer survival from common cancers than Sweden. This may be related to a lower awareness of cancer symptoms and longer patient intervals in Denmark than in Sweden. The aims of this study were to: 1) compare population awareness of three possible symptoms of cancer (unexplained lump or swelling, unexplained bleeding and persistent cough or hoarseness); 2) compare anticipated patient interval when noticing any breast changes, rectal bleeding and persistent cough; and 3) examine whether potential differences were noticeable in particular age groups or at particular levels of education in a Danish and Swedish population sample. Method Data were derived from Module 2 of the International Cancer Benchmarking Partnership. Telephone interviews using the Awareness and Beliefs about Cancer measure were conducted in 2011 among 3000 adults in Denmark and 3070 adults in Sweden. Results Danish respondents reported a higher awareness of two of three symptoms (i.e. unexplained lump or swelling and persistent cough or hoarseness) and a shorter anticipated patient interval for two of three symptoms studied (i.e. any breast changes and rectal bleeding) than Swedish respondents. Differences in symptom awareness and anticipated patient interval between these countries were most pronounced in highly educated respondents. Conclusion Somewhat paradoxically, the highest awareness of symptoms of cancer and the shortest anticipated patient intervals were found in Denmark, where cancer survival is lower than in Sweden. Thus, it appears that these differences in symptom awareness and anticipated patient interval do not help explain the cancer survival disparity between Denmark and Sweden.

Autonomous Research Vessels for Adaptive Upper-Ocean Process Studies

DTIC Science & Technology

2014-09-30

system with the goal  of extending  its mission robustness,  adaptabilit and science capabilities beyond that  of the   Arduino -­‐ based ones... measure the interplay between these finescale dynamics and turbulence, which ultimately drives  the  irreversible  heat/freshwater  transports...profiling in Greenland  Fjords. acquiring CTD cast (and ADCP profiles) within m of a Greenland iceberg.APPROACH: Our first ARV (ARV Rob) was based on

Airborne Lidar Detection and Characterization of Internal Waves in a Shallow Fjord

DTIC Science & Technology

2012-01-01

Graduate Center studying the statistics of optical propagation through refractive turbulence in the clear atmosphere . He then became a member of...instrumentation comprised a Seabird conductivity, temperature, depth (CTD) profiler with a Wetlabs AC-9 to measure the optical absorption and beam ...the depolarization of an initially polarized beam will be D, .=■ 2-d \\-d (10) where D is the ratio of the backscattering perpendicular to the

Genetic variation in mitochondrial DNA among Enterobius vermicularis in Denmark.

PubMed

Ferrero, Mario Rodrıguez; Röser, Dennis; Nielsen, Henrik Vedel; Olsen, Annette; Nejsum, Peter

2013-01-01

Despite being the most prevalent nematode infections of man in Western Europe and North America, our knowledge of the genetic variability in Enterobius vermicularis is fragmented. We here report on a genetic study of pinworms in Denmark, performed using the cytochrome oxidase I (cox1) gene, with DNA extracted from individual eggs collected from clinical (human) samples. We collected cellophane-tape-test samples positive for pinworm eggs from 14 Departments of Clinical Microbiology in Denmark and surface-sterilized the eggs using a 1% hypochlorite solution before performing conventional PCR. Twenty-two haplotypes were identified from a total of 58 Danish patients. Cluster analysis showed that all Danish worms grouped together with human samples from Germany and Greece and with samples from Japanese chimpanzees designated as 'type B'. Analysis of molecular variance showed no significant difference or trends in geographical distribution of the pinworms in Denmark, and several haplotypes were identical or closely related to samples collected in Germany, Greece and Japan. However, worms from the 4 countries were found to belong to different populations, with Fst values in the range of 0·16 to 0·47. This study shows pinworms in Denmark to be a homogenous population, when analysed using the cox1 mitochondrial gene.

'Angels in nursing': images of nursing sisters in a Lutheran context in the nineteenth and twentieth centuries.

PubMed

Malchau, Susanne

2007-12-01

This article examines Catholic nursing orders in Denmark. In 1849, 300 years after the Reformation, freedom of worship was introduced in Lutheran Denmark. In 1856 the first Catholic nursing order in modern times settled in the country. Others followed, and in 1940 the nursing orders owned 17 general hospitals and had a share of 10% of the hospital beds in Denmark. The purpose of this article is to identify images in the public media text of these Catholic nursing orders in Denmark from 1856 to the present, and to deconstruct the existing angel image the nuns and sisters in nursing have obtained. The assumption is that the public image is an important indicator of how a profession is valued in society. Six images - three positive and three negative - are identified, and it is demonstrated that these images were closely connected to the nursing sisters' professional activities and confessional affiliation. Until the 1950s the image of nursing sisters as representing a counterculture in Lutheran Denmark persisted. This image was succeeded by one of professional nurses of high standards. The shift was caused by increased secularisation and the renewal of religious life, as a result of the Second Vatican Council in the 1960s.

Mortality and life expectancy of people with alcohol use disorder in Denmark, Finland and Sweden

PubMed Central

Westman, J; Wahlbeck, K; Laursen, T M; Gissler, M; Nordentoft, M; Hällgren, J; Arffman, M; Ösby, U

2015-01-01

Objective To analyse mortality and life expectancy in people with alcohol use disorder in Denmark, Finland and Sweden. Method A population-based register study including all patients admitted to hospital diagnosed with alcohol use disorder (1 158 486 person-years) from 1987 to 2006 in Denmark, Finland and Sweden. Results Life expectancy was 24–28 years shorter in people with alcohol use disorder than in the general population. From 1987 to 2006, the difference in life expectancy between patients with alcohol use disorder and the general population increased in men (Denmark, 1.8 years; Finland, 2.6 years; Sweden, 1.0 years); in women, the difference in life expectancy increased in Denmark (0.3 years) but decreased in Finland (−0.8 years) and Sweden (−1.8 years). People with alcohol use disorder had higher mortality from all causes of death (mortality rate ratio, 3.0–5.2), all diseases and medical conditions (2.3–4.8), and suicide (9.3–35.9). Conclusion People hospitalized with alcohol use disorder have an average life expectancy of 47–53 years (men) and 50–58 years (women) and die 24–28 years earlier than people in the general population. PMID:25243359

Explanations of sleep paralysis among Egyptian college students and the general population in Egypt and Denmark.

PubMed

Jalal, Baland; Simons-Rudolph, Joseph; Jalal, Bamo; Hinton, Devon E

2014-04-01

This cross-cultural study compared explanations of sleep paralysis (SP) in two countries and two groups with different levels of education in one country. Comparisons were made between individuals having experienced SP at least once in a lifetime from Cairo, Egypt (n = 89), Copenhagen, Denmark (n = 59), and the American University in Cairo, Egypt (n = 44). As hypothesized, participants from the general Egyptian population were more likely to endorse supernatural causal explanation of their SP compared to participants from Denmark; participants from the American University in Cairo were less likely to endorse supernatural causes of their SP compared to participants from the general Egyptian population. Moreover, participants from the American University in Cairo were marginally significantly more likely to endorse supernatural causes of their SP compared to participants from Denmark. Additionally, we explored which culturally bound explanations and beliefs about SP existed in Egypt and Denmark. We found that nearly half (48%) of the participants from the general Egyptian population believed their SP to be caused by the Jinn, a spirit-like creature with roots in Islamic tradition, which constitutes a culturally bound interpretation of the phenomenology of SP in this region of the world. Case studies are presented to illustrate these findings.

Landslide and Tsunami in Karrat Fjord, Greenland, 2017; the Event, the Response and the Future

NASA Astrophysics Data System (ADS)

Langley, K.; Mätzler, E.; Barba, M.; Bojesen, M. H.; Caduff, R.; O'Cofaigh, C.; Dehls, J. F.; 1, G. W. G.; Glimsdal, S.; Harbitz, C. B.; Hermanns, R. L.; Kaab, A.; Kibenich, B.; Kvistedal, Y.; Langeland, H.; Larsen, Y.; Løvholt, F.; Lynett, P. J.; Morin, P. J.; Odermatt, L.; Rignot, E. J.; Sparrevik, P.; Wiesmann, A.; Willis, M.; Zinglersen, K. B.

2017-12-01

On the evening of 17 June 2017, a landslide released from a rock slope in the Karrat Fjord, West Greenland. A section 800 m in breadth detached from an elevation of 1000 m a.s.l. and plunged into the fjord below causing a tsunami. The result was loss of life and injury, devastation and evacuation of local villages, and the revelation that the mountain side is unstable in other places. The humanitarian effort, both locally and international to ease the situation for locals has been outstanding. Here we describe how the sequence of events surrounding the landslide unfolded and, thanks to the rapid response and cooperation by a multi-disciplinary, international team of geoscientists, crucial information could be provided to the Greenlandic authorities that supported and aided decision making. Photography and video from the first response teams showed the path of the landslide. Initial analysis of optical (Planet Cubesat constellation, Sentinel-2), SAR (Sentinel-1) and photogrammetric data from before and after the event confirmed the location of the landslide and the area that had detached. By extending the time series of Sentinel-1 data, it was possible to show that the section had been active since March 2017 with displacement accelerating towards failure. The new ArcticDEM was used to give an estimate of area and volume displacement in the main slide. The area where material was lost covered 760 x103 m2 and amounted to a displaced volume of >50 mio m3. These approaches all identified other parts of the mountain side that are in motion. Tsunami modelling was used to predict the on land inundation with simulations based on the landslide dimensions and a bathymetry model from multi beam surveys. The model results matched extremely well with reconstructed run-up heights manually interpreted from video and photographic footage and seismic analyses. For optimizing the guidance of the Greenlandic authorities, all results and experience from the many involved scientists and institutions were summarized in a number of memos. This knowledge provided information crucial for the response team, their activities and decisions regarding the future of the evacuated villages. A detailed understanding of the landslide and other areas of high risk is of importance in discussions of future mapping and monitoring of geohazards in Greenland.

What do Westerly Wind Reconstructions from Fiordland, New Zealand, say about Southern Hemisphere Paleoclimatic Mechanisms?

NASA Astrophysics Data System (ADS)

Knudson, K. P.; Hendy, I. L.; Neil, H.

2010-12-01

The Southern Hemisphere westerly winds (SWW) have a major influence over deep ocean ventilation around Antarctica and are modulated by inter-annual and decadal climate variability, such as El Niño-Southern Oscillation (ENSO), Inter-decadal Pacific Oscillation (IPO), and Southern Annular Mode (SAM). Fiordland, New Zealand (44.5-46.5°S), is optimally located for reconstructing the SWW, since the fjord sediments record changes in precipitation dependent on the strength and position of the SWW. Here we present a multi-proxy precipitation reconstruction from three New Zealand fjords, demonstrating SWW variability during the late-Holocene, and compare our results to other climate records from New Zealand, Patagonia, and Antarctica. Our fjord sediment analysis uses bulk sediment δ13C and organic C/N ratios to determine the relative contributions of terrestrial organic matter (TOM) versus marine suspended organic matter (SPOM), indicative of terrestrial runoff due to precipitation. Our data indicate dry conditions in Fiordland at 1500-1100 and 750-150 yr B.P., with a reversal at 400 years B.P., and wet conditions at 2300-1600 and 1100-750 yr B.P., with short reversals around 1900 and 900 yr B.P. Our precipitation reconstruction linked to SWW variability provides significant implications for interpreting other Southern Hemisphere climate records and better understanding Pacific basin-wide SWW behavior. Locally, wet periods are likely associated with intervals of increased westerly flow over Fiordland, such as -SAM, El Niño, and/or +IPO, while dry periods may be associated with +SAM, La Niña, and/or -IPO. Comparison of our New Zealand record with Patagonian precipitation records shows differences, which may be attributed to regional variations of the expression of SAM, ENSO, and IPO. In contrast, Fiordland precipitation records appear to correlate to West Antarctic ice cores suggesting a linkage via SAM. Finally, Fiordland precipitation may be modulated by the position of the Subtropical Convergence Zone (STCZ) in the Tasman Sea, which has control over the moisture sources within the SWW path. Therefore, wet periods in Fiordland may be amplified by a southern position of the STCZ that caused the SWW to encounter a warm moisture source before reaching Fiordland.

Trace metal cycling and 238U/235U in New Zealand's fjords: Implications for reconstructing global paleoredox conditions in organic-rich sediments

NASA Astrophysics Data System (ADS)

Hinojosa, Jessica L.; Stirling, Claudine H.; Reid, Malcolm R.; Moy, Christopher M.; Wilson, Gary S.

2016-04-01

Reconstructing the history of ocean oxygenation provides insight into links between ocean anoxia, biogeochemical cycles, and climate. Certain redox-sensitive elements respond to changes in marine oxygen content through phase shifts and concomitant isotopic fractionation, providing new diagnostic proxies of past ocean hypoxia. Here we explore the behavior and inter-dependence of a suite of commonly utilized redox-sensitive trace metals (U, Mo, Fe, and Mn) and the emerging ;stable; isotope system of U (238U/235U, or δ238U) in New Zealand fjords. These semi-restricted basins have chemical conditions spanning the complete redox spectrum from fully oxygenated to suboxic to intermittently anoxic/euxinic. In the anoxic water column, U and Mo concentrations decrease, while Fe and Mn concentrations increase. Similarly, signals of past euxinic conditions can be found by U, Mo, Fe, and Mn enrichment in the underlying sediments. The expected U isotopic shift toward a lower δ238U in the anoxic water column due to U(VI)-U(IV) reduction is not observed; instead, water column δ238U profiles are consistent in fjords of all oxygen content, falling within previously reported ranges for open ocean seawater (δ238U = -0.42 ± 0.07‰). Additionally, surface sediment δ238U results show evidence for competing U isotope fractionation processes. One site indicates increased export of 238U from seawater to the underlying sediments (fractionation between aqueous seawater U and particulate sediment U, or ΔU(aq)-U(solid) = -0.25‰), consistent with redox-driven fractionation. Another site suggests potential U(VI) adsorption-driven fractionation, reflecting increased export of 235U from seawater to sediments (ΔU(aq)-U(solid) = 0.25‰). We discuss several potential factors that could alter δ238U in waters and sediments beyond redox-driven shifts, including adsorption to organic matter in waters of high primary productivity, reaction rates for competing processes of U adsorption and release, and isotopic constraints of U coming into the system from terrestrial environments. These potential complications should be understood and constrained through observations, experiments, and models before future application of δ238U as a global paleoredox tracer can achieve its full potential.

Educational Governance in Denmark

ERIC Educational Resources Information Center

Moos, Lejf

2014-01-01

Denmark has entered global competition by expanding collaboration with European countries, which is profoundly impacting the public sector and school governance. Relations between the state and institutions are transforming from traditional democratic, public-sector models of governance into new forms characterized as corporate and market-driven…

Trends and differences in tuberculosis incidences and clustering among natives in Denmark, Sweden and Finland: comparison of native incidences and molecular epidemiology among three low-incidence countries.

PubMed

Pedersen, M K; Lillebaek, T; Andersen, A B; Soini, H; Haanperä, M; Groenheit, R; Jonsson, J; Svensson, E

2018-07-01

To compare the epidemiology of tuberculosis (TB) in Denmark, Sweden and Finland, by focusing on the native population in order to identify epidemiologic differences and thus indirectly possible differences in TB control. TB incidence trends from 1990 through 2015 were compared among the countries. In addition, for the periods 2012-2013 and 2014-2015, genotyping data were compared. Genotyping was performed using the 24-locus mycobacterial interspersed repetitive unit-variable number of tandem repeat (MIRU-VNTR) method in Denmark and Sweden. For Finland, spoligotyping in conjunction with the 15-locus MIRU-VNTR method was used for 2012-2013 and translated into the 24-locus MIRU-VNTR when feasible, and for 2014-2015 only MIRU-VNTR was used. Both incidence trends and molecular epidemiology were assessed for native cases. The average annual rate of change in TB incidence for native Danes was -2.4% vs. -6.1% and -6.9% for native Swedes and Finns respectively. In 2012-2013 Denmark had 52 native cases in the largest transmission chain vs. three cases in Sweden and ten in Finland, and during the same period the clustering rate for native Danes was 48.8% vs. 6.5% and 18.2% for native Swedes and Finns respectively. For 2014-2015, a similar pattern was seen. The decline of TB among natives in Denmark is slower than for Sweden and Finland, and it seems Denmark has more active transmission among natives. The focused assessment on basic native TB epidemiology reveals striking differences in TB transmission among otherwise similar low-TB-incidence countries. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Prevalence of urinary incontinence among women and analysis of potential risk factors in Germany and Denmark.

PubMed

Schreiber Pedersen, Louise; Lose, Gunnar; Høybye, Mette Terp; Elsner, Susanne; Waldmann, Annika; Rudnicki, Martin

2017-08-01

Urinary incontinence (UI) is a prevalent condition that interferes with women's health-related quality of life. Prevalence rates from earlier studies are wide-ranging, due to heterogeneity in methodology, definition of UI and the populations included. We aimed to determine the prevalence of UI and associated risk factors in Germany and Denmark using the same methodology, definition and population. A postal survey was conducted in two regions in Germany and Denmark, including 8000 women aged 18+ years. UI was defined as any complaint of involuntary loss of urine. The questionnaire contained socio-demographic questions and the International Consultation on Incontinence Modular Questionnaire Urinary Incontinence Short Form (ICIQ-UI SF). The response rate in Germany and Denmark was 46.2 and 66.6% (p < 0.001) and the prevalence rate of UI was 48.3 and 46.4% (p = 0.188), respectively. Stress urinary incontinence dominated among younger women, and urgency urinary incontinence and mixed urinary incontinence among women 80+ years in Germany and Denmark, respectively. The subgroup of women with body mass index (BMI) ≥35 had the highest prevalence of UI (67.3%). The subgroup of women with BMI <35 were more likely to have stress urinary incontinence, and the subgroup of women with BMI ≥35 were more likely to have mixed urinary incontinence. UI was significantly associated with age as with BMI, vaginal delivery, chronic obstructive pulmonary disease, and having at least one co-morbidity. Prevalence rates in the two regions in Germany and Denmark were similar, despite significantly different response rates. This difference may reflect various attitudes towards answering a questionnaire, but the response rate on questions concerning UI seemed consistent. © 2017 Nordic Federation of Societies of Obstetrics and Gynecology.

Contraceptive use in the Nordic countries.

PubMed

Lindh, Ingela; Skjeldestad, Finn E; Gemzell-Danielsson, Kristina; Heikinheimo, Oskari; Hognert, Helena; Milsom, Ian; Lidegaard, Øjvind

2017-01-01

The aim was to compare contraceptive use in the Nordic countries and to assess compliance with recommendations from the European Medicines Agency regarding the use of combined oral contraception containing low-dose estrogen and levonorgestrel, norethisterone or norgestimate. Data on hormonal contraceptive prescriptions and sales figures for copper intrauterine devices were obtained from national databases and manufacturers in Denmark, Finland, Iceland, Norway and Sweden in 2010-2013. Contraceptive use was highest in Denmark (42%) and Sweden (41%), followed by Finland (40%). Combined oral contraception was the most used method in all countries, with the highest use in Denmark (26%). The second most used method was the levonorgestrel-releasing intrauterine system, with the highest use in Finland (15%) and ≈10% in the other countries. Copper intrauterine devices (7%) and the progestin-only pill (7%) were most often used in Sweden. Combined oral contraception use decreased with increasing age and levonorgestrel-releasing intrauterine system and progestin-only pills use increased. The use of long-acting reversible methods of contraception (=levonorgestrel-releasing intrauterine system, copper intrauterine devices, and implants) increased with time and was highest in Sweden (20%) and Finland (18%). The highest use of European Medicines Agency recommended combined oral contraception was in Denmark, increasing from 13 to 50% between 2010 and 2013. In Finland, recommended combined oral contraception remained below 1%. Contraceptive use was highest in Denmark and Sweden, levonorgestrel-releasing intrauterine system use was highest in Finland and all long-acting methods were most common in Sweden. The use of combined oral contraception recommended by the European Medicines Agency was highest in Denmark. © 2016 Nordic Federation of Societies of Obstetrics and Gynecology.

Patterns of finasteride use in the male populations of four Nordic countries: A cross-national drug utilization study.

PubMed

Kjærulff, T M; Ersbøll, A K; Green, A; Emneus, M; Pukkala, E; Bolin, K; Stavem, K; Iversen, P; Brasso, K; Hallas, J; Thygesen, L C

2016-06-01

Objective Finasteride 5 mg is a drug used to treat prostate hyperplasia. Little is known about its pattern of usage. This cross-national analysis of individual-level data from Denmark, Finland, Norway and Sweden was undertaken to appraise its usage and describe cross-national differences. Materials and methods Individual-level data from nationwide prescription registers in Denmark (1995-2009), Finland (1997-2010), Norway (2004-2009) and Sweden (July 2005-2011) were used to examine cross-national finasteride utilization patterns in the adult male population (≥15 years). The study presents period prevalences, incidence rates, waiting time distributions and Lorenz curves. Results During the study period, 295,620 men had at least one prescription redemption of finasteride 5 mg, and there were approximately 3 million dispensing events of finasteride prescriptions in the four Nordic countries. Different patterns of finasteride use were observed among the four Nordic countries. The period prevalence was markedly higher in Finland and Sweden than in Denmark and Norway. In 2009, period prevalences were 18.2/1000 males in Finland and 12.0/1000 males in Sweden compared to 6.7/1000 males in Norway and 4.9/1000 males in Denmark. Incidence rates of finasteride use for Finland, Norway and Sweden were about three times that for Denmark in 2008-2009. Long-term use of finasteride was found in all four Nordic countries with a high ratio between prevalent and incident users. Conclusion Despite resemblances regarding political systems and healthcare services in the Nordic countries, differences in finasteride utilization were found across Denmark, Finland, Norway and Sweden.

Maternal mortality in Denmark, 1985-1994.

PubMed

Andersen, Betina Ristorp; Westergaard, Hanne Brix; Bødker, Birgit; Weber, Tom; Møller, Margrete; Sørensen, Jette Led

2009-02-01

In Denmark, maternal mortality has been reported over the last century, both locally through hospital reports and in national registries. The purpose of this study was to analyze data from national medical registries of pregnancy-related deaths in Denmark 1985-1994 and to classify them according to the UK Confidential Enquiry into Maternal Deaths (CEMD). All deaths of women with a registered pregnancy within 12 months prior to the death were identified by comparing the Danish medical registries, death certificates, and relevant codes according to International Classification of Diseases (ICD-10). All cases were classified using the UK CEMD classification. Cases of maternal death were further evaluated by an audit group. 311 cases were classified. 92 deaths (29.6%) occurred 42 days), 1 woman died from a direct obstetric cause, 46 from indirect causes, and 172 from fortuitous causes. Hypertensive disorders of pregnancy were the major cause of direct maternal deaths. The rate of maternal deaths constituted 9.8/100,000 maternities (i.e. the number of women delivering registrable live births at any gestation or stillbirths at 24 weeks of gestation or later). This is the first systematic report on deaths in Denmark based on data from national registries. The maternal mortality rate in Denmark is comparable to the rates in other developed countries. Fortunately, statistics are low, but each case represents potential learning. Obstetric care has changed and classification methods differ between countries. Prospective registration and registry linkage seem to be a way to ensure completion. This retrospective study has provided the background for a prospective study on registration and evaluation of maternal mortality in Denmark.

Effect of fjord geometry on Greenland mass loss in a warming climate (Invited)

NASA Astrophysics Data System (ADS)

Nick, F. M.; Vieli, A.; Andersen, M. L.; Joughin, I. R.

2013-12-01

Over the past decade, ice loss from the Greenland Ice Sheet increased as a result of both increased surface melting and ice discharge through the narrow outlet glaciers. The complicated behaviour of narrow outlet glaciers has not yet been fully captured by the ice-sheet models used to predict Greenland's contribution to future sea level. Here we try to quantify the future dynamic contribution of four major marine terminating outlet glaciers to sea-level rise. We use a glacier flow line model that includes a fully dynamic treatment of marine termini to simulate behavior of Helheim, Kangerdlugssuaq, Petermann and Jakobshavn Isbræ. The contribution from these glaciers to sea-level rise is largely (80%) dynamic in origin and is caused by several episodic retreats past overdeepenings in outlet glacier troughs. Model results show that the shape of the glacier and its fjord can alter how the glacier will respond to a changing climate. Dynamic losses are mainly related to channel geometry and occur when an ice front retreats from a basal high through an overdeepening. Subsequent decelerations in retreat and mass loss mostly coincide with a decrease in water depth as the glacier retreats or re-advances to a new or previous bathymetric high. In some cases, channel narrowing may temporarily slowdown the terminus retreat even when the terminus is located on an upward bed slope.

Low CO2 Sensitivity of Microzooplankton Communities in the Gullmar Fjord, Skagerrak: Evidence from a Long-Term Mesocosm Study

PubMed Central

Horn, Henriette G.; Sander, Nils; Stuhr, Annegret; Algueró-Muñiz, María; Bach, Lennart T.; Löder, Martin G. J.; Boersma, Maarten; Riebesell, Ulf; Aberle, Nicole

2016-01-01

Ocean acidification is considered as a crucial stressor for marine communities. In this study, we tested the effects of the IPCC RPC6.0 end-of-century acidification scenario on a natural plankton community in the Gullmar Fjord, Sweden, during a long-term mesocosm experiment from a spring bloom to a mid-summer situation. The focus of this study was on microzooplankton and its interactions with phytoplankton and mesozooplankton. The microzooplankton community was dominated by ciliates, especially small Strombidium sp., with the exception of the last days when heterotrophic dinoflagellates increased in abundance. We did not observe any effects of high CO2 on the community composition and diversity of microzooplankton. While ciliate abundance, biomass and growth rate were not affected by elevated CO2, we observed a positive effect of elevated CO2 on dinoflagellate abundances. Additionally, growth rates of dinoflagellates were significantly higher in the high CO2 treatments. Given the higher Chlorophyll a content measured under high CO2, our results point at mainly indirect effects of CO2 on microzooplankton caused by changes in phytoplankton standing stocks, in this case most likely an increase in small-sized phytoplankton of <8 μm. Overall, the results from the present study covering the most important part of the growing season indicate that coastal microzooplankton communities are rather robust towards realistic acidification scenarios. PMID:27893740

Candicidin Biosynthesis Gene Cluster Is Widely Distributed among Streptomyces spp. Isolated from the Sediments and the Neuston Layer of the Trondheim Fjord, Norway▿ †

PubMed Central

Jørgensen, Hanne; Fjærvik, Espen; Hakvåg, Sigrid; Bruheim, Per; Bredholt, Harald; Klinkenberg, Geir; Ellingsen, Trond E.; Zotchev, Sergey B.

2009-01-01

A large number of Streptomyces bacteria with antifungal activity isolated from samples collected in the Trondheim fjord (Norway) were found to produce polyene compounds. Investigation of polyene-containing extracts revealed that most of the isolates produced the same compound, which had an atomic mass and UV spectrum corresponding to those of candicidin D. The morphological diversity of these isolates prompted us to speculate about the involvement of a mobile genetic element in dissemination of the candicidin biosynthesis gene cluster (can). Eight candicidin-producing isolates were analyzed by performing a 16S rRNA gene-based taxonomic analysis, pulsed-field gel electrophoresis, PCR, and Southern blot hybridization with can-specific probes. These analyses revealed that most of the isolates were related, although they were morphologically diverse, and that all of them contained can genes. The majority of the isolates studied contained large plasmids, and two can-specific probes hybridized to a 250-kb plasmid in one isolate. Incubation of the latter isolate at a high temperature resulted in loss of the can genes and candicidin production, while mating of the “cured” strain with a plasmid-containing donor restored candicidin production. The latter result suggested that the 250-kb plasmid contains the complete can gene cluster and could be responsible for conjugative transfer of this cluster to other streptomycetes. PMID:19286787

Sediment Properties as Important Predictors of Carbon Storage in Zostera marina Meadows: A Comparison of Four European Areas

PubMed Central

Dahl, Martin; Deyanova, Diana; Gütschow, Silvia; Asplund, Maria E.; Lyimo, Liberatus D.; Karamfilov, Ventzislav; Santos, Rui; Björk, Mats; Gullström, Martin

2016-01-01

Seagrass ecosystems are important natural carbon sinks but their efficiency varies greatly depending on species composition and environmental conditions. What causes this variation is not fully known and could have important implications for management and protection of the seagrass habitat to continue to act as a natural carbon sink. Here, we assessed sedimentary organic carbon in Zostera marina meadows (and adjacent unvegetated sediment) in four distinct areas of Europe (Gullmar Fjord on the Swedish Skagerrak coast, Askö in the Baltic Sea, Sozopol in the Black Sea and Ria Formosa in southern Portugal) down to ~35 cm depth. We also tested how sedimentary organic carbon in Z. marina meadows relates to different sediment characteristics, a range of seagrass-associated variables and water depth. The seagrass carbon storage varied greatly among areas, with an average organic carbon content ranging from 2.79 ± 0.50% in the Gullmar Fjord to 0.17 ± 0.02% in the area of Sozopol. We found that a high proportion of fine grain size, high porosity and low density of the sediment is strongly related to high carbon content in Z. marina sediment. We suggest that sediment properties should be included as an important factor when evaluating high priority areas in management of Z. marina generated carbon sinks. PMID:27936111

Isolation and Physiological Characterization of Psychrophilic Denitrifying Bacteria from Permanently Cold Arctic Fjord Sediments (Svalbard, Norway)

NASA Technical Reports Server (NTRS)

Canion, Andy; Prakash, Om; Green, Stefan J.; Jahnke, Linda; Kuypers, Marcel M. M.; Kostka, Joel E.

2013-01-01

A large proportion of reactive nitrogen loss from polar sediments is mediated by denitrification, but microorganisms mediating denitrification in polar environments remain poorly characterized. A combined approach of most-probable-number (MPN) enumeration, cultivation and physiological characterization was used to describe psychrophilic denitrifying bacterial communities in sediments of three Arctic fjords in Svalbard (Norway). A MPN assay showed the presence of 10(sup 3)-10(sup 6) cells of psychrophilic nitrate-respiring bacteria g(sup -1) of sediment. Fifteen strains within the Proteobacteria were isolated using a systematic enrichment approach with organic acids as electron donors and nitrate as an electron acceptor. Isolates belonged to five genera, including Shewanella, Pseudomonas, Psychromonas (Gammaproteobacteria), Arcobacter (Epsilonproteobacteria) and Herminiimonas (Betaproteobacteria). All isolates were denitrifiers, except Shewanella, which exhibited the capacity for dissimilatory nitrate reduction to ammonium (DNRA). Growth from 0 to 40 degC demonstrated that all genera except Shewanella were psychrophiles with optimal growth below 15 degC, and adaptation to low temperature was demonstrated as a shift from primarily C16:0 saturated fatty acids to C16:1 monounsaturated fatty acids at lower temperatures. This study provides the first targeted enrichment and characterization of psychrophilic denitrifying bacteria from polar sediments, and two genera, Arcobacter and Herminiimonas, are isolated for the first time from permanently cold marine sediments.

Improved monitoring of phytoplankton bloom dynamics in a Norwegian fjord by integrating satellite data, pigment analysis, and Ferrybox data with a coastal observation network

NASA Astrophysics Data System (ADS)

Volent, Zsolt; Johnsen, Geir; Hovland, Erlend K.; Folkestad, Are; Olsen, Lasse M.; Tangen, Karl; Sørensen, Kai

2011-01-01

Monitoring of the coastal environment is vitally important as these areas are of economic value and at the same time highly exposed to anthropogenic influence, in addition to variation of environmental variables. In this paper we show how the combination of bio-optical data from satellites, analysis of water samples, and a ship-mounted automatic flow-through sensor system (Ferrybox) can be used to detect and monitor phytoplankton blooms both spatially and temporally. Chlorophyll a (Chl a) data and turbidity from Ferrybox are combined with remotely sensed Chl a and total suspended matter from the MERIS instrument aboard the satellite ENVISAT (ENVIronmental SATellite) European Space Agency. Data from phytoplankton speciation and enumeration obtained by a national coastal observation network consisting of fish farms and the Norwegian Food Safety Authority are supplemented with data on phytoplankton pigments. All the data sets are then integrated in order to describe phytoplankton bloom dynamics in a Norwegian fjord over a growth season, with particular focus on Emiliania huxleyi. The approach represents a case example of how coastal environmental monitoring can be improved with existing instrument platforms. The objectives of the paper is to present the operative phytoplankton monitoring scheme in Norway, and to present an improved model of how such a scheme can be designed for a large part of the world's coastal areas.

Ocean forces Greenland and Greenland forces the ocean: a two-way exchange at Greenland's marine margins

NASA Astrophysics Data System (ADS)

Straneo, F.

2017-12-01

The widespread speed up of Greenland's glaciers, over the last two decades, was unpredicted, revealing major gaps in our understanding of how ice sheets respond to a changing climate. Increased submarine melting at the edge of glaciers has emerged as a key trigger - indicating that glacier/ocean exchanges must be accounted for in ice sheet variability reconstructions and predictions. In parallel, the increasing freshwater discharge into the ocean, associated with Greenland's ice loss, has the potential to impact the North Atlantic's circulation and climate. Thus glacier/ocean exchanges are also relevant to understanding drivers of past and future changes in the North Atlantic Ocean's circulation. Here, I present recent findings from observations collected at the edge of several Greenland glaciers that reveal how melting is caused by intrusions of warm, subtropical waters into the fjords and enhanced by the release of surface melt hundreds of meters below sea level. Similarly, hydrographic and tracer data collected at the glaciers' margins, and within the glacial fjords, reveal how Greenland meltwater are exported in the form of highly diluted glacially modified waters, often subsurface, and temporally lagged with respect to the meltwater release. These findings underline the need for improved representation of ice/ocean exchanges in models in order understand and predict the ice sheet's impact on the ocean and the ocean's impact on the ice sheet.

Temperature response of denitrification and anaerobic ammonium oxidation rates and microbial community structure in Arctic fjord sediments.

PubMed

Canion, Andy; Overholt, Will A; Kostka, Joel E; Huettel, Markus; Lavik, Gaute; Kuypers, Marcel M M

2014-10-01

The temperature dependency of denitrification and anaerobic ammonium oxidation (anammox) rates from Arctic fjord sediments was investigated in a temperature gradient block incubator for temperatures ranging from -1 to 40°C. Community structure in intact sediments and slurry incubations was determined using Illumina SSU rRNA gene sequencing. The optimal temperature (Topt ) for denitrification was 25-27°C, whereas anammox rates were optimal at 12-17°C. Both denitrification and anammox exhibited temperature responses consistent with a psychrophilic community, but anammox bacteria may be more specialized for psychrophilic activity. Long-term (1-2 months) warming experiments indicated that temperature increases of 5-10°C above in situ had little effect on the microbial community structure or the temperature response of denitrification and anammox. Increases of 25°C shifted denitrification temperature responses to mesophilic with concurrent community shifts, and anammox activity was eliminated above 25°C. Additions of low molecular weight organic substrates (acetate and lactate) caused increases in denitrification rates, corroborating the hypothesis that the supply of organic substrates is a more dominant control of respiration rates than low temperature. These results suggest that climate-related changes in sinking particulate flux will likely alter rates of N removal more rapidly than warming. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Anthropogenic spreading of anguillid herpesvirus 1 by stocking of infected farmed European eels, Anguilla anguilla (L.), in the Schlei fjord in northern Germany.

PubMed

Kullmann, B; Adamek, M; Steinhagen, D; Thiel, R

2017-11-01

The Schlei fjord in northern Germany is the recipient water of a comprehensive eel, Anguilla anguilla (L.), stocking programme. Since 2015, stocked eels become alizarin red S marked, but to date no control mechanism is implemented in this stock enhancement measure to prevent anthropogenic spreading of diseases. Consequentially, it was possible that farmed stocking cohorts of 2015 and 2016 (in total ca. 1040 kg) were subsequently tested positive for anguillid herpesvirus 1 (AngHV 1). For this study, 100 eels [total length (TL) 24.3-72.9 cm, age ca. 1-6 years] were caught in 2016 and investigated with regard to AngHV 1 infection, parasite load (Anguillicoloides crassus) and body conditions. 68% of the eels were found to be virus positive while larger specimens were more often infected. In addition, a fitted generalized linear model (area under the curve = 0.741) demonstrated that an increase in individual TL is accompanied with an increased risk of clinically relevant virus loads. Anguillicoloides crassus turned out to be an important stressor for eels, because parasite and virus load revealed a significant positive correlation. The results of this study evidently show the urgent need of a disease containment strategy for eel stocking programmes. © 2017 John Wiley & Sons Ltd.

Effect of Topography on Subglacial Discharge and Submarine Melting During Tidewater Glacier Retreat

NASA Astrophysics Data System (ADS)

Amundson, J. M.; Carroll, D.

2018-01-01

To first order, subglacial discharge depends on climate, which determines precipitation fluxes and glacier mass balance, and the rate of glacier volume change. For tidewater glaciers, large and rapid changes in glacier volume can occur independent of climate change due to strong glacier dynamic feedbacks. Using an idealized tidewater glacier model, we show that these feedbacks produce secular variations in subglacial discharge that are influenced by subglacial topography. Retreat along retrograde bed slopes (into deep water) results in rapid surface lowering and coincident increases in subglacial discharge. Consequently, submarine melting of glacier termini, which depends on subglacial discharge and ocean thermal forcing, also increases during retreat into deep water. Both subglacial discharge and submarine melting subsequently decrease as glacier termini retreat out of deep water and approach new steady state equilibria. In our simulations, subglacial discharge reached peaks that were 6-17% higher than preretreat values, with the highest values occurring during retreat from narrow sills, and submarine melting increased by 14% for unstratified fjords and 51% for highly stratified fjords. Our results therefore indicate that submarine melting acts in concert with iceberg calving to cause tidewater glacier termini to be unstable on retrograde beds. The full impact of submarine melting on tidewater glacier stability remains uncertain, however, due to poor understanding of the coupling between submarine melting and iceberg calving.

Ocean forces Greenland and Greenland forces the ocean: a two-way exchange at Greenland's marine margins

NASA Astrophysics Data System (ADS)

Stanley, V.; Schoephoester, P.; Lodge, R. W. D.

2016-12-01

The widespread speed up of Greenland's glaciers, over the last two decades, was unpredicted, revealing major gaps in our understanding of how ice sheets respond to a changing climate. Increased submarine melting at the edge of glaciers has emerged as a key trigger - indicating that glacier/ocean exchanges must be accounted for in ice sheet variability reconstructions and predictions. In parallel, the increasing freshwater discharge into the ocean, associated with Greenland's ice loss, has the potential to impact the North Atlantic's circulation and climate. Thus glacier/ocean exchanges are also relevant to understanding drivers of past and future changes in the North Atlantic Ocean's circulation. Here, I present recent findings from observations collected at the edge of several Greenland glaciers that reveal how melting is caused by intrusions of warm, subtropical waters into the fjords and enhanced by the release of surface melt hundreds of meters below sea level. Similarly, hydrographic and tracer data collected at the glaciers' margins, and within the glacial fjords, reveal how Greenland meltwater are exported in the form of highly diluted glacially modified waters, often subsurface, and temporally lagged with respect to the meltwater release. These findings underline the need for improved representation of ice/ocean exchanges in models in order understand and predict the ice sheet's impact on the ocean and the ocean's impact on the ice sheet.

Vocational Education and Training in Denmark. Short Description

ERIC Educational Resources Information Center

Cedefop - European Centre for the Development of Vocational Training, 2012

2012-01-01

Vocational education and training in Denmark has embarked on a process of modernisation aiming at, primarily, increasing flexibility, and individualisation, quality and efficiency. Assessment and recognition of informal and non-formal learning, competence-based curricula, innovative approaches to teaching, and increased possibilities for partial…

26 CFR 521.116 - Reciprocal administrative assistance.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Department of the Ministry of Finance (Generaldirektoren for Skattevaesenet) of Denmark. (b) Information to... transmit to the Chief of the Taxation Department of the Ministry of Finance of Denmark, as soon as..., royalties, salaries, wages, pensions, annuities and other fixed or determinable annual or periodical profits...

26 CFR 521.116 - Reciprocal administrative assistance.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Department of the Ministry of Finance (Generaldirektoren for Skattevaesenet) of Denmark. (b) Information to... transmit to the Chief of the Taxation Department of the Ministry of Finance of Denmark, as soon as..., royalties, salaries, wages, pensions, annuities and other fixed or determinable annual or periodical profits...

26 CFR 521.116 - Reciprocal administrative assistance.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Department of the Ministry of Finance (Generaldirektoren for Skattevaesenet) of Denmark. (b) Information to... transmit to the Chief of the Taxation Department of the Ministry of Finance of Denmark, as soon as..., royalties, salaries, wages, pensions, annuities and other fixed or determinable annual or periodical profits...

26 CFR 521.104 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 19 2010-04-01 2010-04-01 false Definitions. 521.104 Section 521.104 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) REGULATIONS UNDER TAX CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish...

26 CFR 521.104 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 19 2011-04-01 2010-04-01 true Definitions. 521.104 Section 521.104 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) REGULATIONS UNDER TAX CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish...

Differences in survival on chronic dialysis treatment between ethnic groups in Denmark: a population-wide, national cohort study.

PubMed

van den Beukel, Tessa O; Hommel, Kristine; Kamper, Anne-Lise; Heaf, James G; Siegert, Carl E H; Honig, Adriaan; Jager, Kitty J; Dekker, Friedo W; Norredam, Marie

2016-07-01

In Western countries, black and Asian dialysis patients experience better survival compared with white patients. The aim of this study is to compare the survival of native Danish dialysis patients with that of dialysis patients originating from other countries and to explore the association between the duration of residence in Denmark before the start of dialysis and the mortality on dialysis. We performed a population-wide national cohort study of incident chronic dialysis patients in Denmark (≥18 years old) who started dialysis between 1995 and 2010. In total, 8459 patients were native Danes, 344 originated from other Western countries, 79 from North Africa or West Asia, 173 from South or South-East Asia and 54 from sub-Saharan Africa. Native Danes were more likely to die on dialysis compared with the other groups (crude incidence rates for mortality: 234, 166, 96, 110 and 53 per 1000 person-years, respectively). Native Danes had greater hazard ratios (HRs) for mortality compared with the other groups {HRs for mortality adjusted for sociodemographic and clinical characteristics: 1.32 [95% confidence interval (CI) 1.14-1.54]; 2.22 [95% CI 1.51-3.23]; 1.79 [95% CI 1.41-2.27]; 2.00 [95% CI 1.10-3.57], respectively}. Compared with native Danes, adjusted HRs for mortality for Western immigrants living in Denmark for ≤10 years, >10 to ≤20 years and >20 years were 0.44 (95% CI 0.27-0.71), 0.56 (95% CI 0.39-0.82) and 0.86 (95% CI 0.70-1.04), respectively. For non-Western immigrants, these HRs were 0.42 (95% CI 0.27-0.67), 0.52 (95% CI 0.33-0.80) and 0.48 (95% CI 0.35-0.66), respectively. Incident chronic dialysis patients in Denmark originating from countries other than Denmark have a better survival compared with native Danes. For Western immigrants, this survival benefit declines among those who have lived in Denmark longer. For non-Western immigrants, the survival benefit largely remains over time. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

The Effect of Smallpox and Bacillus Calmette-Guérin Vaccination on the Risk of Human Immunodeficiency Virus-1 Infection in Guinea-Bissau and Denmark

PubMed Central

Villumsen, Marie; Jensen, Mette Lundsby; Ravn, Henrik; da Silva, Zacarias J; Sørup, Signe; Baker, Jennifer Lyn; Rodrigues, Amabélia; Benn, Christine Stabell; Roth, Adam E; Aaby, Peter

2017-01-01

Abstract Background The live smallpox and Bacillus Calmette-Guérin (BCG) vaccinations have been associated with better adult survival in both Guinea-Bissau and Denmark. In Guinea-Bissau, human immunodeficiency virus (HIV)-1 became an important cause of death after smallpox vaccination was phased out globally in 1980. We hypothesised that smallpox and BCG vaccinations were associated with a lower prevalence of HIV-1 infection, and we tested this hypothesis in both Guinea-Bissau and Denmark. Methods We conducted 2 studies: (1) a cross-sectional study of HIV infection and vaccination scars in Guinea-Bissau including 1751 individuals and (2) a case-base study with a background population of 46239 individuals in Denmark. In Guinea-Bissau, HIV-1 transmission was almost exclusively sexually transmitted. In Denmark, we excluded intravenous drug users. Data were analyzed using logistic regression. Results Bacillus Calmette-Guérin and/or smallpox vaccination compared with neither of these vaccines was associated with an adjusted odds ratio (aOR) for HIV-1 of 0.62 (95% confidence interval [CI], 0.36–1.07) in Guinea-Bissau and 0.70 (95% CI, 0.43–1.15) in Denmark. We combined the results from both settings in a meta-analysis (aOR = 0.66; 95% CI, 0.46–0.96). Data from Guinea-Bissau indicated a stronger effect of multiple smallpox vaccination scars (aOR = 0.27; 95% CI, 0.10–0.75) as follows: women, aOR = 0.18 (95% CI, 0.05–0.64); men, aOR = 0.52 (95% CI, 0.12–2.33); sex-differential effect, P = .29. Conclusions The studies from Guinea-Bissau and Denmark, 2 very different settings, both suggest that the BCG and smallpox vaccines could be associated with a decreased risk of sexually transmitted HIV-1. It might be informative to pursue this observation and explore possible protective mechanisms as part of the search for an HIV-1 vaccine. PMID:28852677

Evaluation of the high resolution DEHM/UBM model system over Denmark

NASA Astrophysics Data System (ADS)

Im, Ulas; Christensen, Jesper H.; Ellermann, Thomas; Ketzel, Matthias; Geels, Camilla; Hansen, Kaj M.; Plejdrup, Marlene S.; Brandt, Jørgen

2015-04-01

The air pollutant levels over Denmark are simulated using the high resolution DEHM/UBM model system for the years 2006 to 2014. The system employs a hemispheric chemistry-transport model, the Danish Eulerian Hemispheric Model (DEHM; Brandt et al., 2012) that runs on a 150 km x 150 km resolution over the Northern Hemisphere, with nesting capability for higher resolutions over Europe, Northern Europe and Denmark on 50 km x 50 km, 16.7 km x 16.7 km and 5.6 km x 5.6 km resolutions, respectively, coupled to the Urban Background Model (UBM; Berkowicz, 2000; Brandt et al., 2001) that covers the whole of Denmark with a 1 km x 1 km spatial resolution. Over Denmark, the system uses the SPREAD emission model (Plejdrup and Gyldenkærne, 2011) that distributes the Danish emissions for all pollutants and all sectors in the national emission database on a 1 km x 1 km resolution grid covering Denmark and its national sea territory. The study will describe the model system and we will evaluate the performance of the model system in simulating hourly and daily ozone (O3), carbon monoxide (CO), nitrogen monoxide (NO), nitrogen dioxide (NO2) and particulate matter (PM10 and PM2.5) concentrations against surface measurements from eight monitoring stations. Finally we investigate the spatial variation of air pollutants over Denmark on different time scales. References Berkowicz, R., 2000. A Simple Model for Urban Background Pollution. Environmental Monitoring and Assessment, 65, 1/2, 259-267. Brandt, J., J. H. Christensen, L. M. Frohn, F. Palmgren, R. Berkowicz and Z. Zlatev, 2001: "Operational air pollution forecasts from European to local scale". Atmospheric Environment, Vol. 35, Sup. No. 1, pp. S91-S98, 2001 Brandt et al., 2012. An integrated model study for Europe and North America using the Danish Eulerian Hemispheric Model with focus on intercontinental transport. Atmospheric Environment, 53, 156-176. Plejdrup, M.S., Gyldenkærne, S., 2011. Spatial distribution of pollutants to air - the SPREAD model. NERI Technical Report No. 823.

Alcohol-attributed disease burden in four Nordic countries: a comparison using the Global Burden of Disease, Injuries and Risk Factors 2013 study.

PubMed

Agardh, Emilie E; Danielsson, Anna-Karin; Ramstedt, Mats; Ledgaard Holm, Astrid; Diderichsen, Finn; Juel, Knud; Vollset, Stein Emil; Knudsen, Ann Kristin; Minet Kinge, Jonas; White, Richard; Skirbekk, Vegard; Mäkelä, Pia; Forouzanfar, Mohammad Hossein; Coates, Matthew M; Casey, Daniel C; Naghavi, Mohesen; Allebeck, Peter

2016-10-01

(1) To compare alcohol-attributed disease burden in four Nordic countries 1990-2013, by overall disability-adjusted life years (DALYs) and separated by premature mortality [years of life lost (YLL)] and health loss to non-fatal conditions [years lived with disability (YLD)]; (2) to examine whether changes in alcohol consumption informs alcohol-attributed disease burden; and (3) to compare the distribution of disease burden separated by causes. A comparative risk assessment approach. Sweden, Norway, Denmark and Finland. Male and female populations of each country. Age-standardized DALYs, YLLs and YLDs per 100 000 with 95% uncertainty intervals (UIs). In Finland, with the highest burden over the study period, overall alcohol-attributed DALYs were 1616 per 100 000 in 2013, while in Norway, with the lowest burden, corresponding estimates were 634. DALYs in Denmark were 1246 and in Sweden 788. In Denmark and Finland, changes in consumption generally corresponded to changes in disease burden, but not to the same extent in Sweden and Norway. All countries had a similar disease pattern and the majority of DALYs were due to YLLs (62-76%), mainly from alcohol use disorder, cirrhosis, transport injuries, self-harm and violence. YLDs from alcohol use disorder accounted for 41% and 49% of DALYs in Denmark and Finland compared to 63 and 64% in Norway and Sweden 2013, respectively. Finland and Denmark has a higher alcohol-attributed disease burden than Sweden and Norway in the period 1990-2013. Changes in consumption levels in general corresponded to changes in harm in Finland and Denmark, but not in Sweden and Norway for some years. All countries followed a similar pattern. The majority of disability-adjusted life years were due to premature mortality. Alcohol use disorder by non-fatal conditions accounted for a higher proportion of disability-adjusted life years in Norway and Sweden, compared with Finland and Denmark. © 2016 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.

The Scandinavian Fantasy: The Sources of Intergenerational Mobility in Denmark and the US

PubMed Central

Landersø, Rasmus; Heckman, James J.

2017-01-01

This paper examines the sources of differences in social mobility between the U.S. and Denmark. Measured by income mobility, Denmark is a more mobile society, but not when measured by educational mobility. There are pronounced nonlinearities in income and educational mobility in both countries. Greater Danish income mobility is largely a consequence of redistributional tax, transfer, and wage compression policies. While Danish social policies for children produce more favorable cognitive test scores for disadvantaged children, these do not translate into more favorable educational outcomes, partly because of disincentives to acquire education arising from the redistributional policies that increase income mobility. PMID:28649168

The willingness to pay for wait reduction: the disutility of queues for cataract surgery in Canada, Denmark, and Spain.

PubMed

Bishai, D M; Lang, H C

2000-03-01

We estimate demand curves for a one month reduction in waiting time for cataract surgery based on survey data collected in 1992 in Manitoba, Barcelona, and Denmark. Patients answered, "Would you be willing to pay [Bid, B] to reduce your waiting time for cataract surgery to less than one month?" Controlling for SES and visual status, Barcelonan patients have greater WTP for shortened waiting time than the Danes and Manitobans. We estimate the value (in 1992 $) of lost consumer surplus due to the cataract surgery queue at $128 per patient in Manitoba, $160 in Denmark, and $243 in Barcelona.

Spotlight on VET Denmark

ERIC Educational Resources Information Center

Cedefop - European Centre for the Development of Vocational Training, 2012

2012-01-01

This paper presents data on the vocational education and training (VET) in Denmark. VET plays a key role in the Danish strategy for lifelong learning and meeting the challenges of globalisation and technological change. The Danish education and training system comprises a mainstream system providing qualifications at all levels, from compulsory…

Education Policy Outlook: Denmark

ERIC Educational Resources Information Center

Pont, Beatriz; Figueroa, Diana Toledo; Albiser, Etienne; Yee, Hyo Jeong; Skalde, Annette; Zapata, Juliana; Fraccola, Sylvain

2014-01-01

This policy profile on education in Denmark is part of the new Education Policy Outlook series, which will present comparative analysis of education policies and reforms across OECD countries. Building on the substantial comparative and sectorial policy knowledge base available within the OECD, the series will result in a biennial publication…

26 CFR 521.116 - Reciprocal administrative assistance.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) REGULATIONS UNDER TAX CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents... be transmitted directly by the Commissioner of Internal Revenue to the Chief of the Taxation... transmit to the Chief of the Taxation Department of the Ministry of Finance of Denmark, as soon as...

26 CFR 521.116 - Reciprocal administrative assistance.

Code of Federal Regulations, 2011 CFR

2011-04-01

...) REGULATIONS UNDER TAX CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents... be transmitted directly by the Commissioner of Internal Revenue to the Chief of the Taxation... transmit to the Chief of the Taxation Department of the Ministry of Finance of Denmark, as soon as...

Autopsy rate in suicide is low among elderly in Denmark compared with Finland.

PubMed

Ylijoki-Sørensen, Seija; Boldsen, Jesper Lier; Boel, Lene Warner Thorup; Bøggild, Henrik; Lalu, Kaisa; Sajantila, Antti

2014-11-01

National differences in the legislation on cause and manner of death investigation are reflected in a high autopsy rate in suicides in Finland and a low corresponding rate in Denmark. The consequences for mortality statistics of these different investigation practices on deaths classified as suicides in Denmark and Finland, respectively, are not known in detail. The aim of this article was to analyse autopsy rates in deaths classified as suicides, and to identify any differences in investigation practices in deaths with a comparable cause of death, but classified as unnatural deaths other than suicide. Data from the mortality registries were summarised for the years 2000, 2005 and 2010. Autopsy rates (total, forensic and medical) were analysed with regard to deaths classified as suicide, and they were compared for three age groups (1-50 years, 51-70 years and ≥71 years) and for causes of death. Deaths classified as suicide were compared with other unnatural classifications, and comparable causes of death were coded into six subgroups: poisonings, suffocations/strangulations, firearm discharges, drowning/submersions, explosions/flames and other/unspecified causes. The total autopsy rate for suicides was 99.8% in Finland and 13.2% in Denmark. Almost all of these autopsies were conducted as forensic autopsies. In the age group ≥71 years, Danish suicides outnumbered Finnish suicides (410 versus 283). The total autopsy rate was lower in the more senior age group in Denmark (19.5%, 9.9%, 5.6%), whereas it was consistently high in Finland (99.8%, 99.9%, 99.6%). Among Danish deaths due to poisonings, the autopsy rate was 89.5% when these were classified as accidents, but only 20.7% for cases classified as suicides. The number of deaths in the two Danish subgroups was comparable (550 versus 553). In Denmark, the decision regarding the need, if any, for a forensic autopsy is made during the external forensic examination of the body. Our study showed that the limited use of forensic autopsy to confirm the cause of death in deaths classified as suicides raises doubts about the accuracy of the Danish suicide mortality statistics. Our finding is emphasised by those cases in which the cause of death was registered as intentional self-poisoning. The high number of suicides among the elderly in Denmark is striking and begs further investigation and research. Overall, our data from Finland and Denmark reveal striking differences between the two countries and warrant further comparative studies on the subject in other countries. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

CNS infections in Greenland: A nationwide register-based cohort study

PubMed Central

Nordholm, Anne Christine; Søborg, Bolette; Andersson, Mikael; Hoffmann, Steen; Skinhøj, Peter; Koch, Anders

2017-01-01

Background Indigenous Arctic people suffer from high rates of infectious diseases. However, the burden of central nervous system (CNS) infections is poorly documented. This study aimed to estimate incidence rates and mortality of CNS infections among Inuits and non-Inuits in Greenland and in Denmark. Methods We conducted a nationwide cohort study using the populations of Greenland and Denmark 1990–2012. Information on CNS infection hospitalizations and pathogens was retrieved from national registries and laboratories. Incidence rates were estimated as cases per 100,000 person-years. Incidence rate ratios were calculated using log-linear Poisson-regression. Mortality was estimated using Kaplan-Meier curves and Log Rank test. Results The incidence rate of CNS infections was twice as high in Greenland (35.6 per 100,000 person years) as in Denmark (17.7 per 100,000 person years), but equally high among Inuits in Greenland and Denmark (38.2 and 35.4, respectively). Mortality from CNS infections was 2 fold higher among Inuits (10.5%) than among non-Inuits (4.8%) with a fivefold higher case fatality rate in Inuit toddlers. Conclusion Overall, Inuits living in Greenland and Denmark suffer from twice the rate of CNS infections compared with non-Inuits, and Inuit toddlers carried the highest risk of mortality. Further studies regarding risk factors such as genetic susceptibility, life style and socioeconomic factors are warranted. PMID:28158207

Sediment Production and Storage Through a Glacial-Interglacial Cycle on a Cool-Temperate Glaciated Margin

NASA Astrophysics Data System (ADS)

Powell, R. D.

2001-12-01

The southern Alaska margin has high coastal mountains, which coupled with temperate glaciation, result in extremely high modern erosion rates (e.g. Jaeger et al., 2001), possibly exceeding rates of orogenic uplift (Meigs and Sauber, 2000). Where measured, modern sediment yields are among the highest of any basin worldwide (Hallet et al., 1996; Elverhoi et al., 1998; Jaeger et al., 1998). In Muir Inlet, Glacier Bay, sediment yields from slowly retreating glaciers decrease logarithmically with decreasing drainage basin area (Powell, 1991), a trend also reflected in regional data synthesized in Hallet et al. (1996). Alley (1997) then hypothesized that if erosion increases with basin area then where two tributaries join, deeper erosion would ensue, which is consistent with linear erosional troughs and hanging valleys. The idea is also consistent with the general downglacier increase in water flux at the glacier bed. However over longer periods, data from seismic profiles of the Gulf of Alaska shelf, show sediment yields are nearly the same through a glacial-interglacial cycle; regional data from other glaciated basins appear to confirm that trend (Elverhoi et al., 1998). If yields are continuously high from bedrock erosion, then why are mountains not eroded to base level because erosion rates are higher than isostatic uplift? Why are trends in yields apparently different during recent retreats with decreasing basin sizes than during longer term glacial cycles? Answers to these questions may be numerous and compound; however, one possibility will be evaluated. We know there is significant modern bedrock erosion occurring during glacial retreat and that also appears to have been the case during advance. Native stories describing the last (Little Ice Age) advance in Glacier Bay describe a large amount of sediment being produced (Powell et al., 1995) indicating that significant erosion was occurring. Fjord-wall stratigraphy shows that sediment had infilled much of the Bay up to ca. 200 m above modern sea level (Goldthwait,1986) prior to the LIA. During that advance, all sediments were then eroded down to bedrock, locally up to 400-500 m below sea level (Powell and Molnia, 1989), and then dumped at the Bay entrance, the site of maximum advance Powell et al., 1995). By inference, because most sediment packages on the shelf are deposited during glacially advanced phases, they probably mostly include sediment redistributed from fjords and inner shelf with a minor component from freshly eroded mountain bedrock. The ELA, under which most erosion may occur (Meigs and Sauber, 2000), lies over fjords during glacial maxima where the glacier is probably thickest with pressure melting and melting/freezing occurring at the bed. Erosion of sediment deposited there during a retreat phase may be enhanced, as may fjord over-deepening, whereas, thinner ice over mountains is likely to be cold at the bed, limiting erosion. As the glacier retreats the ELA moves toward the mountains as may the center of erosion, which then occurs mainly on bedrock. Mountain uplift may be enhanced during interglacials when glacio-isostatic rebound occurs and increased erosion adds to the isostatic effect. Therefore, during glacial-interglacial cycles average sediment yields from a glacier may not vary significantly, but the main centers of erosion change through time as does the eroding substrate and locations of depocenters.

The Development of Educational Accountability in China and Denmark

ERIC Educational Resources Information Center

Rasmussen, Palle; Zou, Yihuan

2014-01-01

In recent decades, the concept of accountability has attracted more and more attention in public governance and management. The management of education is no exception. This article presents and discusses the evolution and current status of educational accountability in two different national contexts, China and Denmark. Two main sectors of…

Wind Technology, Cost, and Performance Trends in Denmark, Germany, Ireland, Norway, the European Union, and the United States: 2007 - 2012; NREL (National Renewable Energy Laboratory)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hand, Maureen

This presentation provides a summary of IEA Wind Task 26 report on Wind Technology, Cost, and Performance Trends in Denmark, Germany, Ireland, Norway, the European Union, and the United States: 2007-2012

26 CFR 521.111 - Pensions and life annuities.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 19 2012-04-01 2010-04-01 true Pensions and life annuities. 521.111 Section 521... UNDER TAX CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish Corporations § 521.111 Pensions and life annuities. Under the provisions of Article...

26 CFR 521.111 - Pensions and life annuities.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 26 Internal Revenue 19 2014-04-01 2010-04-01 true Pensions and life annuities. 521.111 Section 521... UNDER TAX CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish Corporations § 521.111 Pensions and life annuities. Under the provisions of Article...

26 CFR 521.111 - Pensions and life annuities.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 19 2013-04-01 2010-04-01 true Pensions and life annuities. 521.111 Section 521... UNDER TAX CONVENTIONS DENMARK General Income Tax Taxation of Nonresident Aliens Who Are Residents of Denmark and of Danish Corporations § 521.111 Pensions and life annuities. Under the provisions of Article...

A Comparison of Autism Prevalence Trends in Denmark and Western Australia

ERIC Educational Resources Information Center

Parner, Erik T.; Thorsen, Poul; Dixon, Glenys; de Klerk, Nicholas; Leonard, Helen; Nassar, Natasha; Bourke, Jenny; Bower, Carol; Glasson, Emma J.

2011-01-01

Prevalence statistics for autism spectrum disorders (ASD) vary widely across geographical boundaries. Some variation can be explained by diagnostic methods, case ascertainment and age at diagnosis. This study compared prevalence statistics for two distinct geographical regions, Denmark and Western Australia, both of which have had population-based…

Snapshots of Language and Literature Teaching in Denmark and England

ERIC Educational Resources Information Center

Kelly, Peter; Dorf, Hans

2016-01-01

To illustrate differences in lower secondary-level language and literature teaching, we contrast a typical teaching episode in Denmark with one in England. Both reflect the dominant discourses in each country alongside recent policy initiatives, and each exemplifies a different orientation to language and literature teaching focussing on…

Denmark's Boernehavens: A Place to Grow

ERIC Educational Resources Information Center

Mecham, Neil A.

2010-01-01

During the author's trips to Denmark as an instructor of American college students studying abroad, he led groups to visit several "boernehavens," which are the Danish equivalents of U.S. preschools for children ages 3 to 5. Danish society values confident individuals who can take initiative when faced with challenges and opportunities.…

Shakespeare, Chekhov and the Emergence of the Transcultured Self in Denmark

ERIC Educational Resources Information Center

Klimenko, Svetlana

2003-01-01

This paper discusses ways in which theatre practices reflect the dynamics of historical development seen from the perspective of transculturation (Epstein, 1995). The analysis is centred on modes of appropriation of Shakespeare and Chekhov in Denmark. The argument relies on a broader statistical investigation into repertoire development, but…

National Tests in Denmark: CAT as a Pedagogic Tool

ERIC Educational Resources Information Center

Wandall, Jakob

2017-01-01

This article describes standardised testing in Denmark and the protections guaranteed to avoid "high stakes". It explains the use of computer-based "adaptive tests" which adjust to an appropriate level for each student. It is an abbreviated version of an article from 2011 in the "Journal for Applied Testing…

Vocational Education and Training in Denmark: Short Description. CEDEFOP Panorama Series.

ERIC Educational Resources Information Center

Cort, Pia

Denmark has a uniform, nationwide vocational education and training (VET) system that provides qualifications that are valid throughout the country and recognized by employers and trade unions. Initial VET (IVET) includes the following components: VET, including commercial and technical training; basic social and health care training; agricultural…

Overwintering Strategies of the Calanoid Copepod Calanus plumchrus in a Periodically Anoxic British Columbia Fjord.

DTIC Science & Technology

1982-10-01

such as copepods, euphausids and pteropods in the water column (Sameoto, 1976; Hansen and Dunbar, 1971 ). When such organisms are concentrated in large...responsible for the acoustic volume reverberation he observed at 330 KHZ in the Western Pacific. Bary and Pieper ( 1971 ) working in Saanich Inlet, B.C...and chitin account for 8.5% of the total dry weight (Ikeda, 1972), the lipid analyses of Lee ( 1971 and 1974) would indicate that the total protein