Temperatures, salinity, wind speed, grain sizes and foraminifera abundance in the Great Belt Channel, western Baltic Sea

The Great Belt, the largest inlet to the Baltic Sea, has a deep and well defined channel system. A distinct thermohaline layer at roughly 18 to 20 m of water depth separates the saltier and generally cooler deeper North Sea water from the brackish and warmer surface water. It is practically a current dominated area, with the strongest bottom currents due to prolonged west winds. The size and shape of the surface sediments and their grain size distributions show a close relationship with the prevailing hydrographical conditions. Southerly current marks predominate while northerly directions are confined to 10 to 14 m of water depth. The degree of bioturbation is highest in the uppermost sedimentary cover where practically all original stratification has been destroyed. Various bioturbate structures have been identified with the fauna. Coiling ratios of Ammonia beccarii (Linnaeus) have been successfully applied for correlation in the postglacial sediments of the early Littorina Transgression. The succession shows that in the Boreal brackish water conditions were probably followed by peat and limnic sediments as the sea regressed. With the Littorina Transgression, the sea again entered the area and high sedimentation rates resulted in the major deposits of the Great Belt. At least for the last 4000 years, sedimentation rates had been very low. Present day currents sweep out the sediments, mainly to the southern marginal areas.

The great south land; the river Plate and southern Brazil of to-day,

Mode of access: Internet.

Chile: its land and people; the history, natural features, development and industrial resources of a great South American republic,

Mode of access: Internet.

Beyond the great south wall: the secret of the Antarctic /

Unnumbered preliminary leaf, entitled "List of illustrations", does not reflect this paperback edition.

Differences in diet of Atlantic bluefin tuna (Thunnus thynnus) at five seasonal feeding grounds on the New England continental shelf

The stomachs of 819 Atlantic bluefin tuna (Thunnus thynnus) sampled from 1988 to 1992 were analyzed to compare dietary differences among five feeding grounds on the New England continental shelf (Jeffreys Ledge, Stellwagen Bank, Cape Cod Bay, Great South Channel, and South of Martha’s Vineyard) where a majority of the U.S. Atlantic commercial catch occurs. Spatial variation in prey was expected to be a primary influence on bluefin tuna distribution during seasonal feeding migrations. Sand lance (Ammodytes spp.), Atlantic herring (Clupea harengus), Atlantic mackerel (Scomber scombrus), squid (Cephalopoda), and bluefish (Pomatomus saltatrix) were the top prey in terms of frequency of occurrence and percent prey weight for all areas combined. Prey composition was uncorrelated between study areas, with the exception of a significant association between Stellwagen Bank and Great South Channel, where sand lance and Atlantic herring occurred most frequently. Mean stomach-contents biomass varied significantly for all study areas, except for Great South Channel and Cape Cod Bay. Jeffreys Ledge had the highest mean stomach-contents biomass (2.0 kg) among the four Gulf of Maine areas and Cape Cod Bay had the lowest (0.4 kg). Diet at four of the five areas was dominated by one or two small pelagic prey and several other pelagic prey made minor contributions. In contrast, half of the prey species found in the Cape Cod Bay diet were demersal species, including the frequent occurrence of the sessile fig sponge (Suberites ficus). Prey size selection was consistent over a wide range of bluefin length. Age 2–4 sand lance and Atlantic herring and age 0–1 squid and Atlantic mackerel were common prey for all sizes of bluefin tuna. This is the first study to compare diet composition of western Atlantic bluefin tuna among discrete feeding grounds during their seasonal migration to the New England continental shelf and to evaluate predator-prey size relationships. Previous studies have not found a common occurrence of demersal species or a pre-dominance of Atlantic herring in the diet of bluefin tuna.

Recovery of the Gulf of Maine--Georges Bank Atlantic herring (Clupea harengus) complex: perspectives based on bottom trawl survey data

NMFS bottom trawl survey data were used to describe changes in distribution, abundance, and rates of population change occurring in the Gulf of Maine–Georges Bank herring (Clupea harengus) complex during 1963–98. Herring in the region have fully recovered following severe overfishing during the 1960s and 1970s. Three distinct, but seasonally intermingling components from the Gulf of Maine, Nantucket Shoals (Great South Channel area), and Georges Bank appear to compose the herring resource in the region. Distribution ranges contracted as herring biomass declined in the late 1970s and then the range expanded in the 1990s as herring increased. Analysis of research survey data suggest that herring are currently at high levels of abundance and biomass. All three components of the stock complex, including the Georges Bank component, have recovered to pre-1960s abundance. Survey data support the theory that herring recolonized the Georges Bank region in stages from adjacent components during the late 1980s, most likely from herring spawning in the Gulf of Maine.

Model-Based Estimates of Right Whale Habitat Use in the Gulf of Maine

Balancing human uses of the marine environment with the recovery of protected species requires accurate information on when and where species of interest are likely to be present. Here, we describe a system that can produce useful estimates of right whale Eubalaena glacialis presence and abundance on their feeding grounds in the Gulf of Maine. The foundation of our system is a coupled physical-biological model of the copepod Calan us finmarchicus, the preferred prey of right whales. From the modeled prey densities, we can estimate when whales will appear in the Great South Channel feeding ground. Based on our experience with the system, we consider how the relationship between right whales and copepods changes across spatial scales. The scale-dependent relationship between whales and copepods provides insight into how to improve future estimates of the distribution of right whales and other pelagic predators.

Regional-Scale Mean Copepod Concentration Indicates Relative Abundance of North Atlantic Right Whales

Management plans to reduce human-caused deaths of North Atlantic right whales Eubalaena glacialis depend, in part, on knowing when and where right whales are likely to be found. Local environmental conditions that influence movements of feeding right whales, such as ultra-dense copepod patches, are unpredictable and ephemeral. We examined the utility of using the regional-scale mean copepod concentration as an indicator of the abundance of right whales in 2 critical habitats off the northeastern coast of the United States: Cape Cod Bay and Great South Channel. Right whales are usually found in Cape Cod Bay during the late winter and early spring, and in the Great South Channel during the late spring and early summer. We found a significant positive relationship between mean concentration of the copepod Calanus finmarchicus in the western Gulf of Maine and the frequency of right whale sightings in the Great South Channel. In Cape Cod Bay we found a significant positive relationship between the mean concentration of other copepods (largely Pseudocalanus spp. and Centropages spp.) and the frequency of right whale sightings. This information could be used to further our understanding of the environmental factors that drive seasonal movement and aggregation of right whales in the Gulf of Maine, and it offers a tool to resource managers and modelers who seek to predict the movements of right whales based upon the concentration of copepods.

Age determination and stable isotope ratios of three sediment cores from the Great Belt

The marine transgression Into the Baltic Sea through the Great Belt took place around 9,370 calibrated C-14-years B.P. The sedimentary sequence from the early brackish phase and the change to marine conditions has been investigated in detail through C-14-datings, and oxygen and carbon isotope measurements, and is interpreted by comparison with modern analogs. The oldest brackish sediments are the strongly laminated clays and silts rich in organic carbon followed by non-laminated heavily bioturbated silts. The bedding and textural characteristics and stable isotope analyses on Ammonia beccarii (dextral) and A. beccarii (sinistral) show that the deposltlonal conditions respond to a change at about 9,100 cal. a B.P. from an unstratified brackish water environment in the initial stage of the Littorina Transgression to a thermohaline layered milieu in the upper unit. The oxygen isotope results indicate that the bottom waters of this latter period had salinities and temperatures comparable to the present day Kiel Bay waters. The isotopic composition of the total organic carbon and the d13C-values of A. beccarii reveal a gradual change from an initially lacustrine/terrestrial provenance toward a brackish/marine dominated depositional environment. A stagnation of the sea level at around 9,100 to 9,400 B.P. is indicated.

An environmental assessment of the John Pennekamp Coral Reef State Park and the Key Largo Coral Reef Marine Sanctuary (Unpublished 1983 Report)

The Pennekamp Coral Reef State Park was established in 1960 and the Key Largo National Marine Sanctuary in 1975. Field studies, funded by NOAA, were conducted in 1980 - 1981 to determine the state of the coral reefs and surrounding areas in relation to changing environmental conditions and resource management that had occurred over the intervening years. Ten reef sites within the Sanctuary and seven shallow grass and hardbottom sites within the Park were chosen for qualitative and quantitative studies. At each site, three parallel transects not less than 400 m long were run perpendicular to the reef or shore, each 300 m apart. Observations, data collecting and sampling were done by two teams of divers. Approximately 75 percent of the bottom within the 18-m isobath was covered by marine grasses, predominantly turtle grass. The general health of the seagrasses appeared good but a few areas showed signs of stress. The inner hardbottom of the Park was studied at the two entrances to Largo Sound. Though at the time of the study the North Channel hardbottom was subjected to only moderate boat traffic, marked changes had taken place over the past years, the most obvious of which was the loss of the extensive beds of Sargassum weed, one of the most extensive beds of this alga in the Keys. Only at this site was the green alga Enteromorpha encountered. This alga, often considered a pollution indicator, may denote the effects of shore run off. The hardbottom at South Channel and the surrounding grass beds showed signs of stress. This area bears the heaviest boat traffic within the Park waters causing continuous turbidity from boat wakes with resulting siltation. The offshore hardbottom and rubble areas in the Sanctuary appeared to be in good health and showed no visible indications of deterioration. Damage by boat groundings and anchors was negligible in the areas surveyed. The outer reefs in general appear to be healthy. Corals have a surprising resiliency to detrimental factors and, when conditions again become favorable, recover quickly from even severe damage. It is, therefore, a cause for concern that Grecian Rocks, which sits somewhat inshore of the outer reef line, has yet to recover from die-off in 1978. The slow recovery, if occurring, may be due to the lower quality of the inshore waters. The patch reefs, more adapted to inshore waters, do not show obvious stress signs, at least those surveyed in this study. It is apparent that water quality was changing in the keys. Water clarity over much of the reef tract was observed to be much reduced from former years and undoubtedly plays an important part in the stresses seen today over the Sanctuary and Park. (PDF contains 119 pages)

Distribuição de elementos tóxicos no estuário do rio Amazonas

A presença de elementos não essenciais nas águas superficiais do rio Amazonas é uma preocupação global, o objetivo da pesquisa foi estudar a distribuição dos elementos As, Al, Mn, e Pb na água do estuário do rio Amazonas. As amostras foram coletadas em três regiões distintas: Canal Norte (AP), Canal Sul (PA) e rio Pará (PA) em três profundidades, com um total de 84 amostras. A espectrometria de emissão atômica com plasma indutivamente acoplado (ICPAES) foi utilizada para avaliar os teores de Al, Mn e Pb e a espectrofotometria de absorção atômica com geração de hidretos (HGAAS) foi usada para a análise do As. O As variou de <0,35 a 50,60 µg/L, o Al de <1,88 a 3347,70 µg/L, o Mn de 0,13 a 403,39 µg/L e Pb de <0,18 a 57,78 µg/L. Em média As (canal Sul), Al (todas as regiões), Mn (canal Norte e Sul) e Pb (canal Norte e Sul) se encontraram em valores acima do permitido pela legislação brasileira. Os elementos podem ter origem antrópica originária de atividade de mineração e industrial e origem natural proveniente de decomposição de rochas ígneas da bacia de drenagem do rio Amazonas que disponibilizam o elemento na forma ligada ao material particulado em suspensão.

Suffolk County survey series; Report.

Cover title.