Recent depositional conditions in the St. Lawrence River and Gulf — A reconnaissance survey

The results of a sedimentological reconnaissance in the area of the River and Gulf of St. Lawrence are discussed. The study is mainly concerned with the relationship between submarine topography, surface sediments, sediment sources and present processes of deposition.The bathymetry of the basin revealed that Pleistocene glaciation largely determined the present shape of the St. Lawrence submarine trough. The distribution pattern of the sediments is fairly regular and characterized by poorly sorted coarse grained nearshore deposits and an extensive area of soft pelite bottom in the deeper parts of the trough. Inspection of the PDR sections shows that the thickness of the soft sedimentary top layer, which forms the postglacial sediment addition, varies strongly regionally and the maximum thickness is 72 ft. In the area between Quebec city and the mouth of the Saguenay River stiff heavy pelites were found to be the characteristic deposits; they are not recent but residual from former conditions. The importance of ice-rafting as a dispersing agent is demonstrated and the cause of the almost constant granulometrical composition of the material < 16 μ for the postglacial pelites discussed.The mineralogy of the sands has shown the presence of unstable heavy and light mineral assemblages throughout the basin. The mineralogical composition indicates that the crystallines of the Canadian Shield are the principal sources for the sands. The chemistry of the sediments has emphasized the lack of intensive chemical decomposition of the source material. The physical conditions in the area set it apart as a particular environmental type.     

The 1995 FAO Code of Conduct for Responsible Fisheries: Adopting,implementing or scoring results?

The paper presents the results of a major assessment of Code adoption and implementation in nine fishing countries in Asia (China, Thailand, Vietnam), Africa (Senegal, Guinea Bissau and Guinea) and in the Caribbean (Jamaica, Dominican Republic and Trinidad & Tobago), which are part of the international research project ECOST. The main findings are that the Code as an international policy instrument remains relevant and adaptable to the current international fisheries context, and that its guiding principles and provisions have been endorsed and adopted in almost unanimous fashion by the countries covered, and integrated into fisheries policy letters and legal frameworks. However, results also suggest that tackling the truly difficult issues in fisheries, such as combating illegal, unreported and unregulated (IUU) fishing or adjusting fishing overcapacity has been a lot less successful. The design and implementation of necessary measures often remains very weak in domains with important economic and political dimensions. The causes for this are attributed to a mix of administrative inertia, lack of political will and stamina, and short-sighted economic considerations.     

Ground-Based Measurements of the Total Column of Freons in the Atmosphere near St. Petersburg (2009–2017)

The results of the first long-term (2009–2017) ground-based spectroscopic measurements of the total content (TC) of a number of freons in Russia are presented. According to measurements in Peterhof, TCs of CFC-11 and CFC-12 decrease at a rate of ~0.6% per year and TC of HCFC-22 grows at a rate of ~2.7% per year, which is in good agreement with independent measurements. The seasonal course of freon TC in the area of St. Petersburg is registered: highs of CFC-11 and CFC-12 are observed in summer and lows are in late winter and spring. For the HCFC-22 TC, the opposite seasonal course is observed, with a maximum in winter and a minimum in summer.     

Importance of microzooplanktonic crustaceans in the coastal food chain: Bay of Marennes-Oléron,France

Modelling biological processes in marine ecosystems requires a good knowledge of the relationships between the different compartments of the ecosystems. Microzooplanktonic crustaceans are often neglected in field feeding studies, due to the difficulties in identification and to their small size. In coastal areas, difficulties are enhanced by the great quantities of particulate organic matter in the water column.Euterpina acutifrons is the major component of the zooplankton community in the Bay of Marennes-Oléron (south-west France) during the algal spring bloom (nauplii strongly dominate the copepod community). The grazing impact of the copepod Euterpina acutifrons (microzooplanktonic and mesozooplanktonic fractions) on the algal standing stock was estimated in the Marennes-Oléron Bay during this period by means of both laboratory experiments and field data. The results suggest that grazing pressure of the microzooplanktonic stages was similar to the pressure exerted by the mesozooplanktonic ones, underlining the significant role of small copepod stages in marine systems in terms of grazing impact. Our results indicate that the daily grazing pressure exerted by the whole population is quite low in the Marennes-Oléron Bay (about 15 % of the algal standing stock).     

Can formalisation help? The introduction of fisheries co-management in the inshore fisheries of Dingle,Co. Kerry,Ireland

Fisheries co-management is claimed to increase the legitimacy of regulations by allocating management authority to selected users. In this article, experiences from a case study in the inshore fisheries of Ireland involving the establishment of a fisheries co-management system are used to discuss the specific problem of finding an unit to whom regulatory authority may be delegated. Here, the fishers who will benefit from the co-management scheme will also carry the costs, and it is argued that establishment of formal economic liability between those granted management privileges and those excluded can optimise the legitimacy of management authority in fisheries co-management systems.     

Dissolved iron distributions in the central region of the Gulf of California,México

We report dissolved iron (Fe_d) concentrations measured in the upper 600 m in the central region of the Gulf of California (GC) under spring conditions. Our results showed the complex nature of Fe cycling within the GC. In the northern region of the study area, surface waters were relatively enriched, with Fe_d concentrations >5.0 nM, which can be partially explained by an atmospheric source. These concentrations are 12 times higher than those found in the adjacent Pacific Ocean. In contrast, Fe_d depth profiles in the southern region did not show any Fe_d surface enrichment (concentrations <1.5 nM) because of particle scavenging and higher stratification of the water-column. The most southern station in our area of study was the most stratified and showed an excess Fe_d and PO₄ with respect to NO₃, conditions favorable for nitrogen fixation. This station also showed the least negative surface value of N* of all stations. However, despite the adequate levels of Fe_d and PO₄ at that location, the surface temperature (22.6 °C) was probably not high enough for diazotrophs to develop. A slight increase in Fe_d levels in intermediate waters at the southern region was associated with the oxygen minimum zone. Finally, our results suggest that remineralization of organic matter is probably the major source of Fe_d in subsurface waters of the GC.     

Evolution of provenance in the NE Atlantic rift: The Early–Middle Jurassic succession in the Heidrun Field,Halten Terrace,offshore Mid-Norway

An integrated provenance study using provenance-sensitive heavy mineral ratios, mineral chemistry and U/Pb dating of detrital zircons has revealed significant changes in sediment provenance during deposition of the Early to Middle Jurassic succession in the Heidrun Field, offshore Mid-Norway. The variations result from the interplay of two source regions, one of which was located on the Norwegian landmass and the other on the conjugate East Greenland margin. Sediment sourced from central East Greenland is distinguished by high garnet:zircon, high rutile:zircon, low chrome spinel:zircon, garnet assemblages rich in low-Ca, high-Mg varieties, and zircon populations that include an Archean group, a diverse range of Early–Middle Proterozoic grains, and an Early Paleozoic group. These features indicate derivation from a high-grade (granulite facies) metasedimentary terrain together with Archean basement and Early Paleozoic granitoids. Norwegian-sourced sandstones differ by having lower garnet:zircon and rutile:zircon, variable chrome spinel:zircon, garnet assemblages scarce in low-Ca, high-Mg varieties, and zircon populations that lack an Archean group. Derivation from the Caledonian Nappe Domain, comprising metasediments (predominantly at amphibolite facies), ophiolites and Early Paleozoic granitoids, is indicated. Initially, during deposition of the non-marine lower part of the Åre Formation (Hettangian–Sinemurian), sediment was fed from the west, but in the upper (tidally influenced) part of the Åre Formation (Sinemurian–Pliensbachian), Norwegian-sourced material appears. Greenland-derived material disappears in the subsequent Tilje Formation (Pliensbachian), with the Tilje and subsequent Ror and Ile Formations (Toarcian–Aalenian) being predominantly sourced from the east. The regional regression at the base of the Garn Formation (Bajocian) was accompanied by a switch in provenance, with Greenland-derived material replacing sediment sourced from Norway. Variations in mineralogy offer a framework for correlation on both local and sub-regional scales.     

Contemporary challenges: globalisation,global interconnectedness and that ‘there are not plenty more fish in the sea’.: Fisheries,Governance and globalisation: is there a relationship?

The article offers an analysis of the globalisation debate in the context of international fisheries governance. It argues that there are significant transformations in fisheries policy-making in international economics, international institutions and international law-making which alter state authority in fisheries management. Thus, decision-making at international, regional and national levels is increasing, displaced from the state level. This ‘multi-level’ decision-making is exemplified in the United Nations Food and Agricultural Organisation's Code of Conduct for Responsible Fisheries, 1995. The Code represents a sound instrument of fisheries governance, capable of responding to contemporary global transformations. Changes are illustrated by comparing the Code and the Agreement on Straddling Fish Stocks and Highly Migratory Fish Stocks, 1995, in the areas of international economics, institutions and law-making. Reference is made to interaction between a range of actors and to formal and informal procedures. In conclusion, a process of ‘fisheries governance’ is confirmed, emerging from a new environment of international fisheries relations.     

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 Ctenophore,Beroe ovata Bruguière, 1789 – the New Invader in the Ecosystem of the Caspian Sea

Oceanology - In November 2020, the invasive ctenophore Beroe ovata Bruguière, 1789 was recorded in samples of gelatinous zooplankton from the northern and central parts of the Caspian Sea. The...     

The artisanal fishery of Cynoscion guatucupa in Argentina: Exploring the possible causes of the collapse in Bahía Blanca estuary

Cynoscion guatucupa Cuvier 1829 is a migratory pelagic fish species, which has a wide geographical distribution. It is the most important fishing resource for local communities in Bahía Blanca estuary and has been captured by artisanal fishermen since the 1900s. The industrial fleet has been fishing this species in the coastal area of Buenos Aires province since the 1950s, and, since 1970, landings have increased sharply. Between 2000 and 2004, the artisanal fishery in the estuarine waters of Bahía Blanca collapsed. Variations in total landings of the artisanal fleet might have arisen from the environmental variables within the estuary, fishing activity in the surrounding sea region, local pressure within the estuary and/or several other variables. Our results suggest that neither oceanographic parameters nor local pressure seem to have influenced the artisanal fishery of C. guatucupa in the estuarine region. Instead, this fishery seems to have been partially influenced by the increasing fishing pressure exerted by the industrial fishing fleet operating in open waters around the estuary. This study emphasizes the need to take into account fisheries data from both the estuarine environment and the surrounding sea region, particularly when designing management plans for the sustainable use of migrating fish resources.     

The chemical characteristics of aerosols in the Kuroshio area——Ⅰ. Sources and fluxes

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The influence of long emersion on biota, ammonium fluxes and nitrification in intertidal sediments of Marennes-Oléron Bay, France

A comparative study between waterlogged and reflooded intertidal sediments was undertaken in March and June 1999 through statistical analysis of selected sediment parameters (biota, salinity, O2, Eh), pool sizes and benthic fluxes of nutrients (NH4+, NO2-, NO3-) and nitrification rates. In March samples, absence of polychaetes and oligochaetes from upper sediment horizons were due to erosional events sweeping away surface sediments. Presence of richer annelid assemblages in June samples indicated more stable hydrodynamic conditions that favoured the development of benthic microalgae biofilms. Dewatering of sediments during a 3-day emersion period promoted a salinity rise on top layers, migration of pore water ions towards the sediment surface, and created sediment fissures that accelerated water exchange on reflooding. Reflooded and waterlogged sediment systems were comparable with respect to the release of NH4+ to overlying water but were different with respect to nitrification rates. Sediment-water NH4+ fluxes were higher (P = 0.011) in March (3.3 mmol m(-2) day(-1) compared to June (1.4 mmol m(-2) day(-1) due to higher macrofauna biomasses and lower benthic microalgae concentrations in March samples. Potential nitrification rates (range from 19 to 60 mmol NO3- (-2) day(-1)) were not statistically different between March and June. A thinner oxic layer in reflooded compared with waterlogged systems reflects a decrease of O2 diffusion into sediment at high salinities which resulted in the fall of the actual nitrification rates (P < 0.05). Our data suggest that long term dessication of intertidal sediments may depress the nitrification process at the ecosystem level.