Plutonium radioisotopes in the surface bottom sediments of the Norwegian and Barents seas.

The joint Swedish-Russian “Tundra Ecology-94” expedition during 1994 used the large Russian ice-breaking research vessel R/V Akademik Fedorov a platform and went along a coastline of 3500 km-from the Kola Peninsula 10°E to Kolyuchinskaya Bay 173°E. Radioactivity in air, seawater and sediment was explored at various locations along the route. The average of 7Be activity concentration in air over the Arctic Ocean was found to be only about 0.6 mBq.m-3, in air close to the Siberian coast-line, however, it was as high as 11 mBq.m-3. The activity concentration of 210Pb in the air over the Arctic Ocean varies between 37 – 176 micro-Bq.m-3. In the air close to the Siberian coastline 71oN 84oE, however, the activity concentration of 210Pb in the air was much higher, about 2500 micro.Bq.m-3. Anthropogenic radioactivity in the Arctic originate from nuclear weapons fallout, release from nuclear fuel reprocessing plant, and from the Chernobyl accident. The minimum values of the 137Cs activity concentration water along the route of the Tundra were found in South-eastern Barents Sea: 5.3 Bq.m-3 of surface-water, and of bottom-water 6.4 Bq.m-3. Maximum values were found in the Western Laptevsea: 12.8 Bq.m-3 of surface-water, and of bottom-water 5.1 Bq.m-3. East of 150 oE the 134Cs / 137Cs ratios are less than 0.003, indicating that less than 6% of the 137Cs originated from the Chernobyl accident. 137Cs levels are reduced to values of about 1.4 Bq.m-3 in the low salinity water near the mouths of the Ob and Yenisey Rivers. The 134Cs / 137Cs activity ratio of 0.014 in the freshwater indicates that the Chernobyl component in the river systems is the same (30%) as in the marine waters west of 150 oE. In surface water the 90Sr activity concentration range from 2 to 4 Bq.m-3, Maximuim values about 3.5 Bq.m-3 were found between 100-140 oE. But east of 150 oE the values decreased to about 0.5 Bq.m-3 at 170 oE. In bottom water the 90Sr activity concentration range from 1.5 at 40 oE to maximum values about 4 Bq.m-3 between 100-120 oE. . The measured 90Sr/137Cs ratios in surface water close to a value of 0.14 over a wide range of stations from the Barents to the Laptev Seas. The 129I concentration in sea-water along the route of the Tundra expedition decrease from about 20·1011 atoms.l-1 at 40 oE, to about 1·1011 atoms.l-1 east of 160 oE. The 239+240Pu activity concentration in surface seawater decrease from about 10 mBq.m-3 to about 1 mBq.m-3 east of 160 oE. In bottom seawater it is more evenly distributed between 10-4 mBq.m-3, with minimum at 60-80 oE and maxima at 40oE and 160 oE. Measured 238Pu/239,240Pu activity ratios in the water column yield no evidence of any leakage of plutonium from dumped nuclear wastes in the Kara and Barents Seas. (Less)

Distributions of fallout 137Cs, 239+240Pu and 241Am in a soil core from South Central China

Distribution of anthropogenic radionuclides in the water column of the south-western Mediterranean Sea

A simple equation using only 137Cs/239+240Pu activity ratios was developed and evaluated as a means of resolving the plutonium in attic dust and soil from Nevada and Utah that came from Nevada Test Site fallout from that which came from global fallout. Applied to an historical data set of 137Cs and 239+240Pu activity concentrations in soils from Nevada and Utah, the activity ratio method gives results similar to the traditional 240Pu/239Pu isotope mass ratio method. Considering the difficulty and expense of determining the 240Pu/239Pu atom ratios, this activity ratio method is simpler, faster, and less costly, and may be useful for detecting and/or monitoring plutonium contamination in soils. Applied to samples of attic dust and soil collected from throughout southern Nevada and Utah during 1996 and 1997, it was found that all sites surveyed showed the presence of Nevada Test Site plutonium. Over 90% of the plutonium found in the samples from Beatty, Tonopah, and Queen City Summit, Nevada, can be attributed to the Nevada Test Site.

Characteristics of artificial radionuclides in sedimentary soil cores from a volcanic crater lake

ABSTRACTMaking use of the OC CCI (Ocean Colour Climate Change Initiative) satellite data, and based on the developed both Emiliania huxleyi bloom contouring methodologies and binary masks, areas of coccolithophore growth were distinguished without supervision from locations of mass developments of other algae. On these grounds, and employing special processing algorithms, multi-year time series of variations in occurrence, surficial extent, and content of particulate inorganic carbon (PIC) within E. huxleyi blooming areas in the North, Norwegian, Greenland, Barents, and Bering Seas were obtained for the time period 1998–2013. Analysis of algorithmic processing of the OC CCI data permitted to reveal the spatio-temporal sequence of E. huxleyi blooming events in the above seas of the North Atlantic and Arctic Oceans. During the intra-annual cycle, E. huxleyi blooms advance from temperate to higher latitudes along the pathways of the Gulf Stream propagation to the north. Annually, the blooms arise in the vicinity of the Great Britain southern extremity, and further on move northward along the western coast of this Island Country, round it to eventually appear first in the North and Norwegian Seas (in early June), then in the Greenland Sea (in late June), and finally in the Barents Sea (in late July–early September). The regularities in dates of bloom outbreak and their duration are revealed. The bloom areas in the North Atlantic–Arctic water are the lowest in the Greenland Sea (10,000–30,000 km2) and by an order of magnitude higher in the Barents Sea. The same pattern holds for the total PIC content within E. huxleyi blooms: 400 t–14 kt in the Greenland Sea and about 0.35 Mt in the Barents Sea. In the Bering Sea, the temporal and spatial dynamics of E. huxleyi development proved to be highly irregular: before and after the 1997–2001 period of high intensity of this phenomenon, the blooms are sporadic, their extent and PIC production are either very low or insignificant. Regarding the range of E. huxleyi bloom areas in the Bering Sea during 1997–2001, it is rather similar to that of the Barents Sea. However, the PIC content in the Bering Sea, as compared to that in the Barents Sea, is higher by a factor of about two with maximum values reaching 0.4 Mt and, on one occasion (in 2001), even about 0.7 Mt.

Plutonium isotopes in surface air at Chiba City, Japan from 2016 to 2023: occurrence of anomalous 238Pu.

This paper presents the analytical results of transuranium radionuclides from sea water samples taken on a research cruise of R.V. Gauss conducted in June/July 1995. Whereas surface samples were frequently taken in the Norwegian, Greenland and Barents Seas during the past decades, this is the first extensive set of large-volume sub-surface samples which were analysed for transuranium elements ( 238 Pu, 239,240 Pu, 241 Am). In comparison with recently published surface results, significantly increased concentrations of plutonium were found in the sub-surface layers of the Norwegian and Greenland Seas. The Pu concentrations show peaks at depths of 100-250 m and 1000-1500 m. The 238 Pu/ 239,240 Pu activity ratio found in both peaks shows a significant influence of the discharges from the Sellafield reprocessing plant. In contrast, Pu activity ratios of fallout origin, or even close to that, are found only in very few samples from the entire area, whether from surface or sub-surface. The geographical extent of the waters marked by Sellafield plutonium covers the area 60°-78° N and 020° W to 040° E in the Barents Sea. As the current releases from the Sellafield works do not correspond with the amount of plutonium found, other possible sources and transport pathways to the Nordic Seas are discussed.

An overview of the ecosystems of the Barents and Norwegian Seas and their response to climate variability

The evolution of the 500 mb height field has been analysed during outbreaks of well-developed polar lows over the Norwegian and Barents Seas using a “superposed epoch method” to composite the data. 42 cases were selected on the basis of synoptic and surface data. In addition, 10 independent cases were chosen on the basis of infrared satellite imagery. To further describe the synoptic climatology of polar low outbreaks, 500 mb temperature, 1000–500 mb thickness, and surface pressure data were each composited for the combined 52 cases of the superposed epoch studies. In order to provide a background from which to evaluate the results of the composite studies, a brief case study of a typical polar low development over the Barents Sea is given. The results of the composite studies reveal the presence of significant negative anomalies in both the temperature and height fields at the 500 mb level over the Norwegian and Barents Seas, indicating strong positive vorticity and very low static stability over the area on the days when mature polar lows were present. The evolution of the height anomaly pattern shows ridging along the west coast of Greenland, and the development of a trough north of Norway, resulting in a northerly component of the flow aloft and at the surface over the Norwegian Sea, as much as 3 days prior to the outbreak of polar lows. The northerly surface flow results in the development of low-level baroclinicity. Evidence suggests that a rapid deepening, characteristic of polar lows, occurs coincident with the outbreak of deep convection. It is suggested that the outbreak of convection is organized by the baroclinicity. The evolution of the negative height anomaly just prior to polar low outbreaks is suggestive of forcing by a migratory short wave aloft. The 1000–500 mb thickness composite supports this view, with the presence of some deeper baroclinicity across the Norwegian Sea. However, comparison of the surface and thickness composites reveals only slight asymmetries in the respective contours, indicating that the atmosphere was nearly equivalent barotropic on the days when strong polar lows were present over the region. The in-situ evolution, and wavelength of the height anomaly pattern suggest that topographical forcing by the high Greenland Plateau, juxtaposed with the warm water of the Norwegian Sea, may enhance the development of polar low outbreaks off the Norwegian coast. DOI: 10.1111/j.1600-0870.1985.tb00441.x

The pteropod Clione limacina (Phipps, 1774) is an arcticboreal, circumpolar species, which is widely distributed in the North Atlantic and Subarctic Oceans; it also occurs in the North Pacific Ocean (in the Oyashio and neighbouring waters) and along the Atlantic coast of North America in the waters of the cold Labrador current to the Cape Hatteras region (35° N). The distribution of C. limacina larvae in the plankton of the Norwegian, Barents and White Seas, the Bear Island-Spitsbergen region of the Greenland Sea, the Newfoundland Grand Bank and the Flemish-Cap Bank region of the North-western Atlantic Ocean, and the Kurile-Kamchatka region of the North-western Pacific Ocean has been studied, and information from literature concerning the reproduction and larval occurrence of the species is summarized. Throughout its distributional are, spawning of C. limacina is characterized by the same general ecological pattern. This species breeds and spawns in all types of water masses occurring within the vertical range which it commonly inhabits — from surface layers to 500 m water depth. In all local populations of the species, the most intensive spawning is correlated with the spring/summer period of annual heating of the local waters, and the highest abundance parallels maximum growth of phytoplankton which serves as food for veligers and early polytrochous larvae. After the end of this period, spawning intensity in all local C. limacina populations declines sharply, but spawning continues at low intensity during the autumn/winter season, being practically continuous throughout the year. Distribution patterns of C. limacina larvae are determined by those of their parental forms (the parental forms spawn in the zones permanently inhabited). The earliest larval stages of C. limacina (veligers) are present predominantly in the upper 100 or 200 m water layer, i.e. in the zone of high phytoplankton abundance. Polytrochous larvae, after becoming predaceous feeders, are distributed throughout the whole water column from the surface to 500 m depth, similar to adult C. limacina. As with the adults, larvae are present (within the species' distribution area) in all types of water masses. Since the beginning of the twentieth century, in the course of the warming of the Arctic Ocean, the southern race of C. limacina (formerly a summer/autumn seasonal invader in the Norwegian Sea) has become a permanent component of the plankton fauna of the Norwegian and Barents Seas in regions influenced by the Norwegian-Northcape Current System.

Determination of the 240Pu/239Pu atomic ratio in soils from Palomares (Spain) by low-energy accelerator mass spectrometry

Based on satellite data, E. huxleyi bloom contouring, quantification of particulate inorganic carbon (PIC) production and increment of CO2 partial pressure, (pCO2) in surface water were performed. 18-year (2003–2021) time series of these variables are obtained for the Norwegian, Greenland and Barents seas. The bloom areas in the North Atlantic–Arctic water are the lowest in the Greenland Sea varying from 10×103 km2 to (20–40)×103 km2. In the Norwegian and Barents Seas they reach in some years (60–80)×103 km2 and (500–600)×103 km2, respectively. The total PIC content within E. huxleyi blooms rarely exceeds in the Greenland and Norwegian seas 12–14 kilotons and 40 kilotons, respectively. In the Barents Sea, in some years, it can be up to 550 kilotons. The highest level of pCO2 within E. huxleyi blooms in surface waters in the Barents Sea was ~350 µatm. In the Norwegian Sea, pCO2 in surface waters within the E. huxleyi bloom was also close to 350 µatm, but most often it remained about 250 µatm. In the Greenland Sea there were only four years of relatively enhanced pCO2 (up to 250 µatm), otherwise remaining below the level of confident determination by our method. As E. huxleyi blooms are generally very extensive, occur throughout the entire World Oceans (and hence in sum occur all year around), this phenomenon has a potential to both decrease to some degree the role of the World Oceans as sinkers of atmospheric CO2, and affect the carbonate counter pump.

A model is presented of the annual consumption of prey by seabirds living in the Norwegian and Barents seas (ICES Areas I, IIa, and IIb) based on the numbers of birds present at any one time, their energy expenditure (and hence their food demand), and the composition of their diet. About 20 million seabirds living in the Barents Sea annually consume approximately 1.16×10 6 t, with Brünnich's guillemots ( Uria lomvia ) taking around 550 000 t (or 47% of the total). Of the total harvest in the Barents Sea, fatty fish constitutes 45% and invertebrates 46%. Annual consumption in the Norwegian Sea is estimated to be 681 000 t by 11 million seabirds of which Atlantic puffins ( Fratercula arctica ) are the major consumers (240 000 t, 36%), followed by northern fulmars ( Fulmarus glacialis ) (200 000 t, 29%). 50% of the harvest in the Norwegian Sea is of lean fish, and 40% invertebrates. Although these consumption rates are probably in the right order of magnitude, errors still arise from uncertainties concerning bird diets and numbers in the region at any one time (especially of birds which breed elsewhere and visit the sea in question outside the breeding season). While the percentages of invertebrates consumed in the two seas are similar, those taken in the Norwegian Sea consist mainly of benthic organisms eaten by common eiders ( Somateria mollissima ) while those eaten in the Barents Sea are mainly pelagic crustaceans taken by Brünnich's guillemots and northern fulmars. Compared to other predators such as cod ( Gadus morhua ), whales, seals, and humans, seabirds account for a minor part (8–15%) of the total harvest and even less (5–11%) of the fish harvest of top predators in the Barents Sea.

The vocalization behavior of fin whales in the Norwegian and Barents Seas is monitored and studied using the Passive Ocean Acoustic Waveguide Remote Sensing (POAWRS) technique. The POAWRS technique is employed to provide detection, bearing-time estimation, time-frequency characterization and classification, as well as localization and geographic positioning of the fin whale vocalizations received instantaneously over wide areas greater than 10,000 km^2. The observations were made from 18 February to 08 March 2014 in several regions of the Norwegian and Barents Seas coinciding with the spawning season and grounds for three commercially and ecologically important fish species: the Atlantic herring (Clupea harengus) off the coast of Alesund, the Atlantic cod (Gadus morhua) off the Lofoten archipelago, and the capelin (Mallotus villosus) off the Northern Finnmark coast. For marine mammals that are top predators, such as the fin whale, the concentrated fish migrations and spawnings are a tremendous source of prey. Since the fin whale is currently on the endangered species list, it is unclear how the recovery of fin whales will impact large oceanic fish stocks in terms of future harvesting potential. It is, therefore, of crucial importance to develop methodologies to observe fin whales over wide areas, such as developing a specific level of array processing to effectively detect specific types of fin whale vocalizations, and gather the information required to understand their behavior, such as their interaction with fish species. In addition, millions of acoustic signals can be received by the POAWRS system per day and are classified by visual inspection and using unsupervised clustering algorithms. This method of classification is performed during post-processing of the data and is a barrier to identifying fin whales vocalizations and other individual sound sources in near real-time. A near real-time detection and classification system is essential for organizations that are required to comply with federal laws and regulations that apply to fin whales, such as the Marine Mammal Protection Act. Hence, an automated classification system is necessary to enable sound sources to be recognized for near real-time fin whale classification applications. There are two main goals of this dissertation. The first is to provide a better understanding of fin whale vocalization behavior in the Norwegian and Barents Seas in terms of sound production, temporal and spatial distributions, and detectability using the POAWRS technique. Here, the objectives to achieve this goal are to (i) provide a time-frequency characterization for different call types observed (20 Hz pulses, 130 Hz upsweeps, 30-100 Hz downsweep chirps, and 18-19 Hz backbeats); (ii) compare their relative abundances in three different coastal regions off Alesund, Lofoten and Northern Finnmark; estimate the (iii) temporal and spatial distributions, (iv) source level distributions, and (v) probability of detection (PoD) regions for the more abundant 20 Hz pulse and 130 Hz upsweep call types. The findings presented here will (1) provide interesting fin whale vocalization behavioral and biological insights; (2) provide time-frequency characteristics that form features that can be used in automatic classifiers for near real-time fin whale detection applications; (3) provide fin whale vocalization rates and location-dependent vocalization rate spatial distribution maps, which can be applied in future studies of predator-prey interactions in the Norwegian and Barents Seas; (4) compare source levels as a means of characterizing different vocalization types; and (5) show that a specific level of array processing is required to effectively detect specific types of fin whale vocalizations in the Norwegian and Barents Seas. The final goal is to develop an automatic classifier for near real-time fin whale detection applications using the time-frequency characterization results from the different fin whale call types observed in the Norwegian and Barents Seas. Here, the objectives to achieve this goal are to (i) gather a large training and test data set of fin whale vocalization detections and other acoustic signals; (ii) build multiple fin whale classifiers, including a logistic regression, support vector machine (SVM), decision tree, convolutional neural network (CNN), and long short-term memory (LSTM) network; (iii) evaluate and compare the performance of each classifier using multiple metrics including accuracy, precision, recall and F1-score; and (iv) integrate one of the classifiers into the existing POAWRS software. The findings presented here will (1) provide an automatic classifier for near real-time fin whale detection applications; and (2) lay the foundation in building an automatic classifier for near real-time detection of various biological, geophysical and man-made sound sources in the ocean environment.