Plio–Quaternary sedimentation processes and neotectonics of the northern continental margin of the South China Sea

Analyses of over 6600 km of reflection seismic profiles on the northern continental margin of the South China Sea permit the recognition of four Quaternary high-frequency type 1 sequences of the 4th order, deposited during the past ca. 690 kyr. At the present-day shelf edge, only lowstand systems tracts characterised by a prograding clinoformal internal reflection pattern are preserved. The prograding complexes can be considered as regressive units accumulated during relative sea-level falls. They exhibit internal discontinuities which might point to minor sea-level fluctuations of the 5th order. A preliminary regional relative sea-level curve for the past 630 kyr is established using the present positions of the delta fronts mapped. The neotectonics curve derived by subtracting eustatic sea-level changes from the relative sea-level curve shows that the depths of the delta fronts today are controlled primarily by regional tectonic movements and the global sea-level.Our seismo-stratigraphic interpretation documents that the area off Hong Kong and around the Dongsha Islands experienced two uplift episodes during the past 5 ma, namely at the Miocene/Pliocene boundary and at the end of the lower Middle Pleistocene, respectively. These uplift events which are centred on the Dongsha Rise led to its subaerial exposure and to the erosion of the Pliocene and most of the Pleistocene strata. The change from thermal subsidence of the continental margin initiated at the end of the drift phase to the phase of magmato-tectonic uplift was caused by a reorientation of the tectonic regime.The Recent depositional environment on the northern continental margin of the South China Sea is dominated by sediment accumulation within the inner shelf and the Zhujiang (Pearl River) estuary. The outer shelf and upper slope, especially around the Dongsha Islands, are characterised by bypass of terrigenous material.The sedimentary column in the deepsea basin has a thickness of more than 2 km and comprises 14 depositional units starting with terrestrial rift deposits. It overlies oceanic as well as transitional crust.     

The “harmful algae and algal toxins in coastal waters of China:investigation and database” project

The “harmful algae and algal toxins in coastal waters of China:investigation and database”project (HAATC) is funded (US$2.3 million) by the Ministry of Science and Technology of China for 60months starting on the 1s t Jan 2019. Since the 1990s, national projects and other related work have greatly improved harmful algal bloom (HAB) research in China. However, the existing research on HABs is often limited to specifi c sea areas or specifi c algal bloom disasters, which is insu ffi cient for unde...     

A comparison of condition factor and gonadosomatic index of sardine Sardinops sagax stocks in the northern and southern Benguela upwelling ecosystems, 1984–1999

Time-series of condition factor (CF) and gonadosomatic index (GSI) were generated using general linear models (GLM) for sardine Sardinops sagax stocks in the northern and southern Benguela ecosystems over the period 1984–1999. During this period the biomass of sardine in the northern Benguela remained at relatively low levels of <500 000 tons, whereas that of southern Benguela sardine increased 40-fold to 1.3 million tons. The GLMs explained 27 and 45% of the observed variation in CF, and 32 and 28% of the observed variation in GSI, for sardine in the northern and southern Benguela subsystems respectively. Whereas the sardine CF in the northern Benguela remained stable over time, that for the southern Benguela stock declined steadily during the study period. Sardine CF showed a seasonal cycle in the southern but not in the northern Benguela. Time-series of GSI showed high interannual variability but no trends in either subsystem, and the seasonal pattern was similar for both stocks. The lack of coherence between the CF time-series for sardine in the two subsystems further suggests that sardine stocks in the northern and southern Benguela subsystems are independent.     

The music of the spheres and the prosaicness of statistical criteria: A response to B.L. Berry’s paper “Heliogeophysical and other natural processes,periods of their oscillations,and forecasts”

According to B.L. Berry’s “harmonic model,” any natural or social process is a superposition of several cosmic rhythms. The author assumes that stability of these rhythms allows prediction of earth phenomena over an unlimited time. We show that the statistical criteria supposedly substantiating the harmonic model were applied incorrectly. The initial data for the analysis were biased and selected incompetently; the adequacy of the methods used was not verified. Predictions of natural catastrophes (earthquakes, weather anomalies, etc.) and various social events according to Berry’s model are unsatisfactory. Statistics do not confirm that these predictions are at least slightly better than random guessing. Berry’s model is unacceptable; it is untenable both in detail and in general.     

The geochemistry of sediments from the northern Reykjanes Ridge and the Iceland—Faroes Ridge

Samples from the active Reykjanes Ridge and the inactive Iceland—Faroes Ridge have been investigated sedimentologically, mineralogically, and geochemically. The sediments display polymodal grain-size distributions and are poorly sorted, indicating deposition by various mechanisms and contributions from numerous sources. The mineralogy is fairly typical for the region and strongly reflects the large input of volcanic ash and ice-rafted material.Bulk chemical analyses indicate that the Reykjanes Ridge sediments appear to be enriched in Fe, Mn, Cu, Cr, and Zn as has been reported for other active ridges while the inactive Iceland—Faroes Ridge does not display such enrichments. The enriched metals in the ridge sediments do not show a particular affinity for any one size class. Partition studies indicate that the enriched Fe and Mn are held in separate phases while the other metals are present in all phases. Adsorption is not a major concentrating mechanism for the enhanced elements.Li distributions are apparently unaffected by active ridges and Pb seems to be partially concentrated biologically. There are indications that other criteria must be used in conjunction with bulk chemical analyses, in order to establish the presence of active ridge metal contributions.     

The spreading of eutrophication in the eastern coast of the Gulf of Bothnia,northern Baltic Sea – An analysis in time and space

In the Baltic Sea, the Gulf of Bothnia is the only sub-basin with only minor effects of eutrophication mainly due to physical factors. Most evaluations of the state of the Gulf of Bothnia are based on offshore investigations. In the present study the coastal zone of the eastern Gulf of Bothnia is analysed. Long-term data (1980–2007) of total nitrogen and phosphorus, turbidity and oxygen are analysed using principal component analysis (PCA) for spatial and temporal patterns in the trophic situation. The coastal zone is divided into six regions: inner and outer areas of the Bothnian Sea and the Quark, and the outer areas of the southern and northern Bothnian Bay. The results show a degradation of water quality from north to south, and from outer to inner coastal areas. Eutrophication changes from an almost non-existing problem in the Bothnian Bay in the north to clear signs of nutrient over-enrichment in the Bothnian Sea. This shows that even if eutrophication in the Gulf of Bothnia is not serious, the increasing trends in nutrient levels should be seen as warning signals for the future, and remedies to combat eutrophication should be taken rapidly.     

The “Tegnue de Ciosa” area: Patch reefs in the northern Adriatic Sea

Exposures of both living and dead biogenic rock built by calcarous algae, madreporaria and serpulids are present in the northern Adriatic Sea. These asymmetrical patch reefs, which project up to 4 m above the present sea floor, are best developed off Chioggia, Italy, in water depths ranging from 17 to 24 m. Side-scan sonar traverses showed that individual reef exposures are areally irregular and ranged in size from roughly 1 to 100,000 m².     

The influence of organic sources and environments on source rock deposition during the periods of Cretaceous–Eocene and Oligocene–Miocene,northern Kalimantan

The sedimentary system of Kalimantan has undergone significant development since the Oligocene. Previous research have largely ignored the capacity of the Cretaceous–Eocene sediments to produce hydrocarbons,focusing instead primarily on the Oligocene–Miocene coal as the principal source rocks. Shales and coals from the outcrops in the northern margin of Kalimantan were analyzed with palynological and geochemical methods to characterize the palaeoenvironmental and palaeoecological differences bet...     

Scalar reorganisation of marine governance in Europe? The implementation of the marine strategy framework directive in Spain,Portugal and Germany

European marine policies have recently been consolidated, and the scalar organisation of marine governance has been questioned. This paper examines this phenomenon in Europe as a result of implementation of the European Marine Strategy Framework Directive (MSFD) and examines changes in the role of the national state vis à vis other levels of jurisdiction in marine policy. The relevance of use pressures differs across European member states, as do national policy styles and institutional configurations. Therefore, a nuanced picture is needed regarding the ways European marine policy is being implemented. To this end, the paper employs a co-evolutionary perspective studying the cases of Germany, Spain and Portugal. European marine policy has become anchored in the most relevant policy fields except agriculture and fisheries, and competency regarding its environmental dimension has been strengthened, formalized and clarified as a result of the MSFD. Its implementation, tied to international marine protection, comes following initiatives to develop maritime economies. In Portugal, implementation of the MSFD did not change the scalar organisation of natural resource governance. In Spain and Germany, the MSFD led to disputes regarding clarification of competencies. In the course of implementing the MSFD in Germany, challenges are tied to the political dimensions of formalizing practices and producing integrated policies. In Spain and Portugal, comprehensive stock-taking is itself a challenging task.     

Bathymetric reconstructions of the Miocene-age “calcari aLucina” (northern Apennines,Italy) from oxygen isotopes and benthic Foraminifera

Two independent methods of paleobathymetry, applicable to hydrocarbon-derived carbonates, are explored in this study. The oxygen isotope method exploits the temperature decline with depth that leaves a measurable imprint on the ¹⁸O composition of pristine products of venting comprised of aragonites and dolomites. The other method makes use of the bathymetric preferences of benthic foraminiferal taxa entrapped in the carbonate buildups. These two methods were tested on the calcari aLucina limestones hosted in turbidites and mudstones infilling the Miocene-age Marnoso-arenacea basin. The limestone blocks, rich in fossils of chemosymbiotic-like fauna, preserve a 10-Ma record of hydrocarbon venting from Langhian to lower Messinian times. Our results indicate that carbonate accretion and lithification occurred at upper bathyal depths in waters not shallower than 200–250 m. The ¹⁸O of venting products contains the imprints of profound hydrographic changes that occurred in the ancient Mediterranean basin from the lower Serravallian to the lower Messinian.     

Observations of boundary layer parameters and suspended sediment transport over the intertidal flats of northern Jiangsu, China

A current-turbidity monitoring system (CTMS) was deployed on the intertidal flat at Wanggang, northern Jiangsu during October 16-17, 2000, to measure the tidal current speeds and seawater turbidities at 5 levels above the seabed. Based upon the logarithmic-prof‘de equation, the boundary layer parameters, i.e., u*, Z0 and C60, were obtained for 247 tidal flow velocity prof‘des. Around 90% of the profiles were logarithmic according to the critical correlation coefficient. Internal consistency analysis shows that these parameters derived by different methods are consistent with each other. In addition, the height of the bedforms observed is close to the seabed roughness lengths calculated from the velocity prof‘des, indicating that the boundary layer parameters obtained can reveal the conditions at the sedimentwater interface on the intertidal flats. Suspended sediment concentrations were obtained from the 5 CTMS turbidity meters using laboratory and in-situ calibrations. The results show that the in-situ calibrated SSCs have a much higher accuracy than the laboratory calibrated ones. Calculation of suspended sediment fluxes on the intertidal flats, with a magnitude of 104 kg/m per spring tidal cycle, indicates that suspended sediment moves towards the northwest, which is reversal to the transport pattern controlled by the southward Northern Jiangsu Coastal Current in the sub-tidal zone and adjacent shallow waters.     

Basic characteristics and forming mechanism of the sharp thermocline in the Bohai Sea, Huanghai Sea and northern East China Sea

- On the basis of the fact that the sharp thermocHne in the Bohai Sea and the northern Huanghai Sea is often distributed in the deep valley areas, it has been long thought that the reason of the formation of the sharp thermocHne is that the cold water can be easily kept in valleys. But recent investigations carried out in the southern Huanghai Sea in summer show that all of the sharp thermocHne areas were distributed in the shallow sloping-bottom areas but not in the deep valley areas. Only in autumn would the sharp thermoclines translate to the deep valley areas. In summer, they are characterized by shallow upper mixing layer and thin thickness in the southern Huanghai Sea. In addition to entrainment coming from lower boundary of upper mixing layer the entrainment from upper border of bottom homogeneous layer induced by tidal mixing also plays an important role in the growth and decay of thermoclines in these seas.     

Trawl fisheries,catch shares and the protection of benthic marine ecosystems: Has ownership generated incentives for seafloor stewardship?

Proponents of catch share-based fisheries have claimed ecological stewardship can result from the assignment of individual catch quotas. This claim is examined by analyzing the distribution of benthic habitat protection measures adopted by quota-owning industry sectors within the exclusive economic zones (EEZs) of the U.S. (Alaska), New Zealand, and high seas seamounts within the Southern Indian Ocean Deepsea Fishers Association (SIODFA) competence area. Results suggest the protection of both benthic ecosystems and essential fish habitat (EFH) are marginal at best when quota owners have primacy in determining the boundaries of bottom trawl closures. The majority of the areas in these three regions that are closed to trawling are too deep to fish, may not contain vulnerable marine ecosystems, and do not have high abundances of commercially important species. “Freezing the footprint” of bottom trawling is not the best method for benthic habitat protection in areas where the fishing industry is actively fishing vulnerable habitats. Analytical methods should be applied to help determine boundaries of future bottom trawl closures rather than allowing the fishing industry to place benthic protection areas (BPAs) in areas where they are not interested in fishing.     

The Study of Fish Eggs, Larvae and Juveniles of the Estuary at Beitang

The fish eggs, larvae and juveniles were collected during 25 cruises from April to No-vember 1980 and 1981 respectively. They were represented by 40 species, 36 genera, 19families and 9 orders. According to their habit, the fish eggs, larvae and juveniles couldbe referred to three types: (1) shallow sea and estuary type; (2) migration type of outersea; (3) fresh water type. The shallow sea and estuary species were 29 in number, occu-pying 72.5% of the total; the migration species were 3 in number, occupying 7.5% of thetotal; the fresh water species were 8 in number occupying 20% of the total.     

Anatomical and ultrastructural comparison of the eyes of two species of aquatic,pulmonate gastropods: The bioluminescent Latia neritoides and the non‐luminescent Ancylus fluviatilis

Light‐adapted eyes of two freshwater gastropods with similar habitat preferences (Latia neritoides (Gray 1850) and Ancylus fluviatilis (Müller 1774)) were compared with each other in relation to optics, anatomy, and ultrastructure. Individuals of L. neritoides not only possess significantly larger eyes than similarly sized A. fluviatilis, they also have a more voluminous layer of photorecep‐tive membranes and appear capable of discerning at least some crude shapes. The eye of A. fluviatilis, on the other hand, has a very shallow retina which is so closely apposed to the lens that it can be little more than an indicator of light and darkness. Both types of eye are generously endowed with screening pigment granules and exhibit no signs of light‐induced damage. Although the lenticular F‐values for L. neritoides (1.78) and A. fluviatilis (1.74) alone are hardly indicative of an adaptation to a dark environment, the greater amount of photic vesicles and the substantial development of muscle fibres in the eye of L. neritoides suggest that the latter can adjust its vision more rapidly to changing light levels than that of A. fluviatilis. Since L. neritoides (but not A. fluviatilis) has the ability to secrete a bright green luminescent mucus, a faster accommodation system would serve the species well. There is, however, no proof that in Latia bioluminescence alone has been responsible for the development of a more capable eye. Most of the differences between the eyes of L. neritoides and A. fluviatilis can be explained by the distinctly greater nocturnal activity of L. neritoides in combination with the ability to produce bright light in the latter species.     

Contrasting volcanic-tectonic processes during the past 2 Ma on the Mid-Atlantic Ridge: submersible mapping,petrological and magnetic results at lat. 34°52′ N and 33°55′ N

In August–September of 1995, 20 Nautile dives and detailed magnetic surveys (spaced every 1.8 km) were undertaken on two segments of the Mid-Atlantic Ridge between the Oceanographer and Hayes fractures zones. These two segments are only 65 km apart and show strong morphology and gravity contrasts. OH1 is shallower and has a large mantle Bouguer anomaly (MBA) bull's eye, whereas OH3 is deeper and has a smaller MBA bull's eye.Thirteen dives were devoted to segment OH1. The Median Ridge (MR) located on the central high (1700 m deep) is topped by 100 to 300 m high circular volcanoes. The volcanics consists mainly of porphyritic and/or vesicular pillows and volcaniclastics. The NVZ (2200 m deep), located in the valley floor east of the MR, consists of near aphyric fluid lava flows. A chain of off-axis volcanoes, displaying a magnetic continuity with surroundings, extends on both sides of the axis. Three volcanoes on the east side and one on the west side of the axis were explored and sampled by submersible. The off-axis increase of weathering, Fe-Mn coating and magnetic signature suggest that the volcanoes were built at or near the ridge axis. The spacing of NS elongated hills bearing circular volcanoes and separated large magnetic signature (2 to 4 km) depressions suggests that several similar volcanic events occured during the past 2 Ma. The last 1 Ma episode involves (1) the construction of an axial ridge (MR) by fissure eruptions and the formation of circular summit volcanoes by focused volcanism, and (2) the extrusion of fluid magma in the depressions formed by further fissuring and faulting of the MR.     

Beach morphology and nearshore processes on a sheltered beach — The case of Napatree Beach,Rhode Island

On the north side of Napatree Beach, short-term changes of the beach-face within the intertidal zone were studied to determine those processes most influential in causing change where nearshore processes are low in magnitude and beach changes are subtle. The data were subjected to multiple linear correlation and stepwise multiple-regression analyses.Tide level accounts for 41% of the explained variation for the relationship between the processes and beach height. Tide level is the only significant element effecting change in the beach profile. Wave height has no influence on changes in beach morphology. Significant results of beach energy associations have been obtained where low-amplitude nearshore processes are present even when beach changes are subtle.     

Palynology and petroleum potential of the Kazhdumi Formation (Cretaceous: Albian–Cenomanian) in the South Pars field,northern Persian Gulf

The Kazhdumi Formation of the Bangestan Group is a well-known source rock that has produced abundant oil in most petroleum fields in the Zagros Basin, which stretches from northwest to southwest Iran over hundreds of kilometres. The formation reaches a thickness of 230 m at the type section in northwest Zagros but thins out to 40–50 m in wells studied from the South Pars giant petroleum field, where it comprises mainly grey shales with occasional intercalations of marls and sandstones. South Pars, best known as the Iranian part of the world's largest non-associated gas field, contains small quantities of oil above and below the Kazhdumi Formation.