Sea Northeast Research Articles

Polychlorinated Biphenyls (Pcbs) Pollution in Sea of Japan

Deep waters of the Sea of Japan and surface waters of the Pacific Coast of Honshu and the northeast Sea of Japan were analysed for polychlorinated biphenyls (PCBs) pollution. the ΣPCB concentrations in solution in the Sea of Japan (50–3000 m) were between 140 and 1230 fg dm−3. the space-integrated surface water concentration near the Pacific coast of northern Honshu was 140 fg dm−3and for the surface water of the Sea of Japan was 230 fg dm−3. Based on these analyses four water masses were deduced in the Sea of Japan during the summer months. It is shown for the first time in the Sea of Japan that polychlorinated biphenyls are excellent chemical indicators of not only the anthropogenic pollution, but also water masses.

Limitation of carbon assimilation of intertidal Zostera noltii and Z. marina by desiccation at low tide

Carbon dioxide assimilation of emersed Zostera noltii leaves was measured by infrared gas analysis to determine its dependence on leaf water content and the duration of air exposure in the tidal flats of the German Wadden Sea (south east North Sea). After 5 h of exposure to air during low tide, leaves of Z. noltii had lost up to 50% of their water content. The degree of leaf water loss rapidly increased with the distance from the water line and, thus, was a function of the duration of exposure. A decrease in leaf water content by about 30% (from 340–390 to 190–250% DW) resulted in a reversible reduction in light-saturated net photosynthesis rate ( A max) of Z. noltii by more than 50% (24–31 nmol CO 2 g DW −1 s −1 vs. 6–14 nmol g DW −1 s −1). Similarly, laboratory experiments with artificially dried leaves showed a decrease of A max by about 40% for a water content reduction from 400 to 270% DW. Drying experiments with leaves of the co-occurring species Z. marina showed a rapid reduction of A max from 30 nmol CO 2 g DW −1 s −1 (at 500% leaf water content) to zero or even negative CO 2 fluxes (at 180% water content). These results indicate that photosynthesis is more sensitive to desiccation in Z. marina than in Z. noltii under a given leaf water content. The two intertidal Zostera species use low tide periods for rapid assimilation of atmospheric CO 2 as long as their leaf water status is favourable, but desiccation can significantly reduce carbon gain at low tides. We conclude that the presence of seagrasses in the tidal flats of the Wadden Sea is primarily restricted by desiccation at the upper limit.

Pre-Zechstein geology of the south-east North Sea, offshore Denmark-a geophysical perspective

The aim of this paper is to present an integrated geophysical study of the pre-Zechstein geology in the south-eastern North Sea, offshore Denmark (Fig. 1). Main tectonic features of the area include the Central Graben in the west, the Horn Graben in the south-east, the East North Sea High in the middle, the Holmsland Block in the east, the southern part of the Norwegian-Danish Basin in the north, as well as the northern part of the North German Basin in the south (Fig. 2). The central part of the study area (i.e. East North Sea High) is commonly regarded as part of the Ringk˘bing-Fyn High, which is a major NWW±ESE trending positive structural element with a relatively thin cover of Mesozoic and Tertiary sediments. This structural high divides the North German Basin from the Norwegian-Danish Basin. The main tectonic features in the area are clearly illustrated by the depth structure of the top pre-Zechstein (base Upper Permian) rock (Fig. 3a). In this study, geophysical evidence is presented to show the existence of substantial amounts of Palaeozoic sediments in the area of the East North Sea High. The interpretation is based on a residual gravity anomaly map of the region, which outlines the potential area of Palaeozoic sediments as indicated by relatively low residual gravity anomalies. Magnetic basement depths of a few selected areas are estimated using available aeromagnetic data. Interpretation of selected seismic sections is carried out to confirm the results derived from the potential field investigations. Finally, the implications of the finding of this study are discussed briefly in terms of the pre-Zechstein geology and the tectonic history of the region as well as its potential relevance to petroleum exploration in the area.

Abstract :Stratigraphic Correlation of Carboniferous Carbonate Reservoirs In the North-East Caspian Sea Region

Abstract :Stratigraphic Correlation of Carboniferous Carbonate Reservoirs In the North-East Caspian Sea Region

The nitrogen isotopic composition of nitrate in the Kuroshio Water northeast of Taiwan: evidence for nitrogen fixation as a source of isotopically light nitrate

The Kuroshio Water, which provides nutrients to the shelf water of the East China Sea through upwelling at the shelf break northeast of Taiwan, is abundant with nitrogen fixing cyanobacteria. Accordingly, the δ15N values of nitrate at three stations in the sea northeast of Taiwan were analyzed to estimate the flux of biologically fixed nitrogen in the Kuroshio Water by characterization of the isotopic signature of the upwelled nitrate. Prior to sample analysis, we verified using standard KNO3 solution the validity of the sample preparation procedure, which has been modified by reducing the amount of Devarda's alloy to lower the reagent blank. However, the concentrations of nitrate in seawaters estimated from the amount of extracted nitrogen were consistently higher than those measured colorimetrically, suggesting interference from dissolved organic nitrogen of which the δ15N value was estimated to be −3.0 ± 0.2%., Correction was made on each sample based on the estimated δ15N for DON. The δ15N values of waters from 500 to 780 m in the sea northeast of Taiwan fell in the range of + 5.5 to + 6.1%c, which was consistent with those observed in deep waters elsewhere. The δ15N values decreased in the overlying Kuroshio Water by 1–3%. in general. In order to achieve isotope balance in the water column, the input of isotopically light nitrogen, presumably from nitrogen fixation, is required. The nitrogen flux from this source was estimated to be 0.5 mg m−2 day−1 N which is only 8% of the estimated new nitrogen to the Kuroshio surface water. On the other hand, this nitrogen may account for 20–40% of the nitrate in the subsurface water (100–400 m) as a result of accumulation and recycling. The nitrate in the source upwelling water had a δ15N value of +4.7 ± 0.6%., implying 20 ± 9% of it originating from nitrogen fixation.

Mode coupling effect of a cold eddy in Taiwan’s Northeast Sea.

The Kuroshio current turns toward the north‐east while it passes the Okinawa Trough in Taiwan’s Northeast Sea. In this region, there are different waters mixing, namely, water from the Taiwan Strait, water of the East China Sea, and the Kuroshio current. During the year, except for the summer months, the Kuroshio current is characterized by its distinct temperature difference from other waters, i.e., the Kuroshio front and cold eddies are two predominant features in this region. The frontal effect on acoustic propagation has been studied and reported in a previous talk. In this paper, the coupling effect of modes when acoustic signals transmit through the cold eddy using both the Parabolic Equation method and the Adiabatic Mode Approximation is reported. Severe mode coupling is realized while the sound transmits through the cold eddy. [Work supported by National Science Council of Republic of China.]

Condensed water in tropical cyclone “Oliver”, 8 February 1993

On February 8, 1993, the NASA DC-8 aircraft profiled from 10,000 to 37,000 feet (3.1–11.3 km) pressure altitude in a stratified section of tropical cyclone “Oliver” over the Coral Sea northeast of Australia. Size, shape and phase of cloud and precipitation particles were measured with a 2-D Greyscale probe. Cloud/ precipitation particles changed from liquid to ice as soon as the freezing level was reached near 17,000 feet (5.2 km) pressure altitude. The cloud was completely glaciated at −5°C. There was no correlation between ice particle habit and ambient temperature. In the liquid phase, the precipitation-cloud drop concentration was 4.0 × 10 3 m −3, the geometric mean diameter D g =0.5−0.7 mm, and the liquid water content 0.7−1.9 g m −3. The largest particles anywhere in the cloud, dominated by fused dendrites at concentrations similar to that of raindrops (2.5 × 10 3 m −3) but a higher condensed water content (5.4 g m −3 estimated) were found in the mixed phase; condensed water is removed very effectively from the mixed layer due to high settling velocities of the large mixed particles. The highest number concentration (4.9 × 10 4 m −3), smallest size ( D g =0.3−0.4 mm), largest surface area (up to 2.6 × 10 2 cm 2 m −3 at 0.4−1.0 g m −3 of condensate) existed in the ice phase at the coldest temperature (−40°C) at 35,000 feet (10.7 km). Each cloud contained aerosol (haze particles) in addition to cloud particles. The aerosol total surface area exceeded that of the cirrus particles at the coldest temperature. Thus, aerosols must play a significant role in the upscattering of solar radiation. Light extinction (6.2 km −1) and backscatter (0.8 sr −1 km −1) was highest in the coldest portion of the cirrus cloud at the highest altitude.

Mode coupling effect of Kuroshio front in Taiwan’s Northeast Sea

The Kuroshio current turns toward the northeast while it passes the Okinawa Trough in Taiwan’s Northeast Sea. In this region, there are different waters mixing, namely, water from the Taiwan Strait, water of the East China Sea, and the Kuroshio current. During the year, except in the summer months, the Kuroshio current is characterized by its distinct temperature difference from other waters, i.e., the Kuroshio front is a predominant feature in this region. The bottom topography in this region is composed of shelf and slope features. The acoustics propagation is studied numerically using the FOR3D code. Severe mode coupling is realized while the sound is transmitted through the Kuroshio front. [Work supported by National Science Council of Republic of China.]

Acoustic transmission of Taiwan’s Northeast Sea

The Northeast Sea of Taiwan is characterized by the turning of the Kuroshio current and mixing of water masses from the same current, East China Sea, and Taiwan strait. Its bottom topography consists of the shelf and the shelf slope. Kuroshio export exchange program (KEEP) was conducted by oceanographers from Taiwan to study the complexities of this region. An acoustic study was also included. An acoustic transmission experiment was conducted via fixed receivers and a towed source emitting cw tone of 170 dB re; 1 μPa, 1 m at 400 Hz along three predetermined tracks in the region. The tracks are of flat bottom and slope bottom. The ambient noise in this region is high; its level reaches 80 dB or higher at 400 Hz. The region is basically a bottom-limited acoustic environment. A PE model was used with an acoustic model constructed by real data of water column and bottom material. The numerical results agree well with the experimental data. The acoustic effect of a cold eddy in the region was studied numerically using a PE model with KEEP oceanography data. A cold eddy of 50 km in diameter along 200-km track was studied. The eddy causes 5 dB more losses in acoustic transmission.

Daytime surface swarms of the euphausiid Thysanoessa inermis off the west coast of Hokkaido, northern Japan

Biological characteristics of the daytime swarming of the euphausiid Thysanoessa inermis (Kroyer) were examined off the west coast of Hokkaido in the northeast Sea of Japan between 1982 and 1987. Swarms were composed exclusively of fully mature individuals; males possessed spermatophores at the ejaculatory ducts and females had attached spermatophores at the thelycum. Females predominated in most swarms, while males or nearly balanced swarms were infrequently encountered. Fully mature females occurred in the late swarming season, usually mid-April. Examination of stomachs indicated that feeding activity was low during the daytime surface swarming behavior. The body sizes of swarming T. inermis occurring around Yagishiri Island were significantly larger than those found simultaneously off the Shakotan Peninsula. This suggests that the euphausiid populations of the two areas are different.

NOAA WP-3D instrumentation and flight operations on AGASP-II

The second Arctic Gas and Aerosol Sampling Program (AGASP-II) was conducted across the non-Soviet Arctic in March and April 1986, to study the aerosol, gaseous, chemical, and optical properties of Arctic haze. One component of the program was supported with an instrumented NOAA WP-3D atmospheric research aircraft. Measurements of wind, temperature, ozone, water vapor, condensation nucleus concentration, and aerosol scattering extinction coefficient were used to determine the locations and properties of haze layers. The first three NOAA WP-3D research flights were conducted north of Barrow, Alaska, and over the Beaufort Sea northeast of Barter Island, Alaska. The next three sampled conditions in the high Arctic near Alert, Northwest Territories, Canada. All basic meteorological, gas, and aerosol systems are described. The WP-3D flight tracks and operations are presented.

The Late Quaternary Skagerrak and its depositional environment

The Skagerrak is a key region for our understanding of the Late Quaternary history of the East North Sea, of the entire Baltic basin and of the adjacent Scandinavian land areas. The depositional history of the postglacial Skagerrak began after the ice margin withdrew from Jutland to close to the modern Norwegian coast around 14 ka B.P. to 13 ka B.P. The Skagerrak was immediately filled by marine waters from the Norwegian Sea, but retained a fjord‐like shape until approximately 10.2 ka B.P., when a connection opened across central Sweden to the Baltic Ice Lake. This seaway closed around 9 ka B.P., but a new seaway to the Baltic basin opened subsequently (probably close to 8.5 ka B.P.) through the Danish Belts. At about 10 ka B.P. the Skagerrak ‘fjord’ also started to change shape due to the flooding of the large former land area under the modern North Sea. Paleo‐geography and ‐bathymetry of these changes can now be quantified in great detail. The young Quaternary sediments of the Skagerrak consist of fine‐grained clays with minor amounts of silty and sandy material and are mostly of terrigenous origin, whereas biogenic components in general make up only a minor proportion of the bulk sediment. Prior to 10 ka B.P. a major portion of these deposits originated from the Fennoscandian regions N and E of the Skagerrak, while ice‐rafting contributed coarse terrigenous components to the usually fine‐grained sediments and while it was filled by brackish surface and cold polar bottom waters. At approximately 10 ka B.P., more temperate waters started to fill the Skagerrak and a good portion of the sediment seems to have originated from areas to the South. The Norwegian Coastal Current can only be documented for the past 7 ka; subtle changes of the pelagic and benthic environments could also be documented for later intervals.

Interannual Variability of the Kuroshio Frontal Structure along Its Western Boundary in the North Pacific Ocean Associated with the 1982 ENSO Event

The vertically averaged temperature (Tav) over the upper 200 m of ocean in the western boundary of the North Pacific is used to detect changes in the strength and path of the Kuroshio Front along the western boundary from Luzon (18°N) to Honshu (34°N) during the period 1979–82. During this time the Kuroshio Front experienced significant interannual changes associated both with the disappearance of the Kuroshio Meander in late 1980 and with the development of the 1982 ENSO event in early 1982. When the Kuroshio Meander south of Honshu disappeared from the fall of 1980, until the summer of 1981, the intensity of the Kuroshio Front increased, associated with warmer than normal temperatures all along the western boundary of the North Pacific from Luzon to Honshu. The amplitude of the Kuroshio Meander was also correlated with fluctuations in the path of the Kuroshio Front at the Tokara Strait (30°N) and the Bashi Strait (20°N) and with the amplitude of the East China Sea Meander. The East China Sea Meander occurs west of the Ryukyu Islands at 25°N, formed when the Kuroshio Current enters the East China Sea from the Philippine Sea northeast of Taiwan Island. It had large amplitude in winter and smaller amplitude in spring and early summer, similar to that in the Kuroshio Meander when it was present during this period. It also had related interannual variability; i.e., when the Kuroshio Meander disappeared in fall of 1980, the East China Sea Meander was weak. These results and earlier ones dealing with the Kuroshio Front cast of Japan (e.g., White and He) indicate that fluctuations in the amplitude of the Kuroshio Meander south of Honshu were associated with similar changes in the mesoscale meandering character over the entire Kuroshio Current System during this four-year period. During the 1982 ENSO event, the temperatures in the region of the Kuroshio Front in the western boundary became colder than normal, while both the Kuroshio Meander south of Honshu and the East China Sea Meander northeast of Taiwan Island developed larger amplitudes. This is consistent with the results of White and He, who found the mesoscale meander pattern in the Kuroshio Extension intensifying during the 1982 ENSO period. During this time, the magnitude of the Kuroshio Front all along the western boundary and in the Kuroshio Extension region was weaker in comparison with the three years prior to the 1982 ENSO event.

東北海区における海況変動に関する二, 三の問題点 (1)

東北海区は黒潮系水の北上と親潮系水の南下との間に混合域があって種々雑多な暖水塊や暖水域が見られ, 日本近海で最も複雑な変動を示している. この海域 (33～43°N, 141～150°E) おいて, 現在の観測体制でその変動・持続性等をミクロに取り上げて解明出来る問題は少ない. 今回マクロに見て, 海況変動に関する二, 三の問題点のうち, 第1報として黒潮と親潮とのパターンとの間の関係について, 100m層水温分布・144°E線上の鉛直断面図等から解析した.黒潮系水 (100m層で15℃, 34.6‰以上の水塊) と親潮系水 (100m層で5℃, 33.60‰以下の水塊) との相互の位置について, 黒潮系水の北上が著しい時, 親潮系水の南下が著しく, その両者の間の水温傾度が急であり, 又逆に黒潮系水の北上が弱い時, 親潮系水の南下が弱く, 両者の水温傾度がゆるやかになっている.

Geology of Orocopia Mountains, Southeastern California: ABSTRACT

The Orocopia Mountains border the Salton Sea northeast of the San Andreas fault in Riverside County, California. The range core, composed of Orocopia schist, is separated on the southwest from End_Page 218------------------------------ deformed late Cenozoic non-marine strata by the Hidden Spring fault zone, a branch of the nearby San Andreas. Northeast of the Orocopia schist a mile-wide wedge of gabbro, diorite, anorthosite, gneiss, and alaskite lies between a northeast-dipping fault, at places folded, and a high-angle major fault marked by great crushing. These rocks, intruded by volcanics and highly deformed, resemble rocks in the western San Gabriel Mountains, about 150 miles northwest. Northeast of the high-angle fault, augen gneiss with migmatite on the southeast and granite on the north underlies unconformably about 4,800 feet of newly discovered fossiliferous marine Eocene strata which are probably correlative with Coast Range middle Eocene. Unconformably overlying this sequence is a 5,000-foot thick variable series of undated non-marine conglomerate, sandstone, shale, and tuff, with volcanic flows and intrusions. In this series, lenses of granitic breccia characterize the northwest, and platy tuffaceous sandstone with gypsum-bearing interbeds the southeast. Major faults separate the area into tectonic blocks of different geologic history, and local correlation across the faults is not possible. Understanding of the significance of these faults and others in the vicinity, like the San Andreas, awaits regional study such as that now underway. Strike separations dominate over dip separations on minor faults associated with complex folds. End_of_Article - Last_Page 219------------

Recent Earthquakes

THE U.S. Coast and Geodetic Survey, in co-operation with Science Service and the Jesuit Seismological Association, has determined the epicentres of two recent earthquakes. The first of these was on June 8 at about 20h. 42.2m. U.T. and occurred near latitude 19° N., longitude 116° E. This is in the South China Sea, west of Luzon in the Philippine Islands. The second was on June 9 at about 3h. 6.7m. U.T. and had its epicentre near latitude 9° N., longitude 120° E., which is in the Sulu Sea north-east of Borneo. On the morning of Friday, July 16, a strong earthquake was felt throughout the Island of Jamaica. The epicentre was some ninety miles from Kingston in the Balaclava district, where some damage was done to property though there are no reports of any loss of life.

V. Short account of the last Russian expedition for making discoveries in the north-east sea

(1798). V. Short account of the last Russian expedition for making discoveries in the north-east sea. The Philosophical Magazine: Vol. 2, No. 6, pp. 141-146.