Occurrence and geochemistry of lake-bottom manganiferous deposits in Canadian lakes

It is the purpose of this paper to record information concerning the distribution and occurrence of manganiferous concretions and other manganese oxide deposits that develop on certain lake bottoms. During the summer of 1935 several days were devoted to a study of this type of lake bottom deposit in various parts of Nova Scotia. Lake studies in Ontario have extended the known distribution from lakes on or near the Atlantic coast to lakes in southern Ontario. During the writer's first work on lacustrine manganiferous deposits the concretions of manganese oxide which were found were almost entirely limited to the relatively shallow parts of the lakes examined. Other lakes are now known where the manganese oxide appears to occur only in the maximum depths.

Geochemistry, clay mineralogy and grain size distribution in various sediment cores drilled during ODP Leg 119 on the Antarctic continental shelf off Prydz Bay

Drilling was undertaken at five sites (739-743) on ODP Leg 119 on a transect across the continental shelf of Prydz Bay, East Antarctica, to elucidate the long-term glacial history of the area and to examine the importance of the area with respect to the development of the East Antarctic ice sheet as a whole. In addition to providing a record of glaciation spanning 36 m.y. or more, Leg 119 has provided information concerning the development of a continental margin under the prolonged influence of a major ice sheet. This has allowed the development of a sedimentary model that may be applicable not only to other parts of the Antarctic continental margin, but also to northern high-latitude continental shelves. The cored glacial sedimentary record in Prydz Bay consists of three major sequences, dominated by diamictite: 1. An upper flat-lying sequence that ranges in thickness from a few meters in inner and western Prydz Bay to nearly 250 m in the outer or eastern parts of the bay. The uppermost few meters consist of Holocene diatom ooze and diatomaceous mud with a minor ice-rafted component overlying diamicton and diamictite of late Miocene to Quaternary age. The diamictite is mainly massive, but stratified varieties and minor mudstone and diatomite also occur. 2. An upper prograding sequence cored at Sites 739 and 743, unconformly below the flat-lying sequence. This consists of a relatively steep (4° inclination) prograding wedge with a number of discrete sedimentary packages. At Sites 739 and 743 the sequence is dominated by massive and stratified diamictite, some of which shows evidence of slumping and minor debris flowage. 3. A lower, more gently inclined, prograding sequence lies unconformably below the flat-lying sequence at Site 742 and the upper prograding sequence at Site 739. This extends to the base of both sites, to 316 and 487 mbsf, respectively. It is dominated by massive, relatively clast-poor diamictite which is kaolinite-rich, light in color, and contains sporadic carbonate-cemented layers. The lower part of Site 742 includes well-stratified diamictites and very poorly sorted mudstones. The base of this site has indications of large-scale soft-sediment deformation and probably represents proximity to the base of the glacial sequence. Facies analysis of the Prydz Bay glacial sequence indicates a range of depositional environments. Massive diamictite is interpreted largely as waterlain till, deposited close to the grounding line of a floating glacier margin, although basal till and debris flow facies are also present. Weakly stratified diamictite is interpreted as having formed close to or under the floating ice margin and influenced by the input of marine diatomaceous sediment (proximal glaciomarine setting). Well-stratified diamictite has a stronger marine input, being more diatom-rich, and probably represents a proximal-distal glaciomarine sediment with the glaciogenic component being supplied by icebergs. Other facies include a variety of mudstones and diatom-rich sediments of marine origin, in which an ice-rafted component is still significant. None of the recovered sediments are devoid of a glacial influence. The overall depositional setting of the prograding sequence is one in which the grounded ice margin is situated close to the shelf edge. Progradation was achieved primarily by deposition of waterlain till. The flat-lying sequence illustrates a complex sequence of advances and retreats across the outer part of the shelf, with intermittent phases of ice loading and erosion. The glacial chronology is based largely on diatom stratigraphy, which has limited resolution. It appears that ice reached the paleoshelf break by earliest Oligocene, suggesting full-scale development of the East Antarctic ice sheet by that time. The ice sheet probably dominated the continental margin for much of Oligocene to middle Miocene time. Retreat, but not total withdrawal of the ice sheet, took place in late Miocene to mid-Pliocene time. The late Pliocene to Pleistocene was characterized by further advances across, and progradation of, the continental shelf. Holocene time has been characterized by reduced glacial conditions and a limited influence of glacial processes on sedimentation.

Early - Late Miocene palaeoclimate data and palaefloras of 48 samples from Southern China

Southern China, especially Yunnan, has undergone high tectonic activity caused by the uplift of Himalayan Mountains during the Neogene, which led to a fast changing palaeogeography. Previous study shows that Southern China has been influenced by the Asian Monsoon since at least the Early Miocene. However, it is yet not well understood how intense the Miocene monsoon system was. In the present study, 63 fossil floras of 16 localities from Southern China are compiled and evaluated for obtaining available information concerning floristic composition, stratigraphic age, sedimentology, etc. Based on such reliable information, selected mega- and micro-floras have been analysed with the coexistence approach to obtain quantitative palaeoclimate data. Visualization of climate results in maps shows a distinct spatial differentiation in Southern China during the Miocene. Higher seasonalities of temperature and precipitation occur in the north and south parts of Southern China, respectively. During the Miocene, most regions of Southern China and Europe were both warm and humid. Central Eurasia was likely to be an arid center, which gradually spread westward and eastward. Our data provide information about Miocene climate patterns in Southern China and about the evolution of these patterns throughout the Miocene, and is also crucial to unravel and understand the climatic signals of global cooling and tectonic uplift.

Seawater carbonate chemistry and calcium carbonate of Padina spp., photosynthesis of Padina pavonica in nature CO2 gradients experiment

Predicting the impacts of ocean acidification on coastal ecosystems requires an understanding of the effects on macroalgae and their grazers, as these underpin the ecology of rocky shores. Whilst calcified coralline algae (Rhodophyta) appear to be especially vulnerable to ocean acidification, there is a lack of information concerning calcified brown algae (Phaeophyta), which are not obligate calcifiers but are still important producers of calcium carbonate and organic matter in shallow coastal waters. Here, we compare ecological shifts in subtidal rocky shore systems along CO2 gradients created by volcanic seeps in the Mediterranean and Papua New Guinea, focussing on abundant macroalgae and grazing sea urchins. In both the temperate and tropical systems the abundances of grazing sea urchins declined dramatically along CO2 gradients. Temperate and tropical species of the calcifying macroalgal genus Padina (Dictyoaceae, Phaeophyta) showed reductions in CaCO3 content with CO2 enrichment. In contrast to other studies of calcified macroalgae, however, we observed an increase in the abundance of Padina spp. in acidified conditions. Reduced sea urchin grazing pressure and significant increases in photosynthetic rates may explain the unexpected success of decalcified Padina spp. at elevated levels of CO2. This is the first study to provide a comparison of ecological changes along CO2 gradients between temperate and tropical rocky shores. The similarities we found in the responses of Padina spp. and sea urchin abundance at several vent systems increases confidence in predictions of the ecological impacts of ocean acidification over a large geographical range.

Sedimentation rates and geochemistry of the Atlantic and Indic Ocean of Late Miocene - Early Pliocene

Studies of the late Miocene-early Pliocene biogenic bloom typically have focused on high-productivity areas in the Indian and Pacific Oceans in order to achieve high resolution samples. Thus there is a paucity of information concerning whether the Atlantic Ocean, in general or low-productivity regions in all three basins experienced this bloom. This study measured the phosphorus mass accumulation rate (PMAR). in five cores from low-productivity regions of the Atlantic and Indian Oceans. All cores exhibit a peak in productivity 4-5.5 Ma, coincident with the Indo-Pacific bloom. This suggests that nutrients were not shifted away from low-productivity regions nor out of the Atlantic Ocean. Instead, it appears that the bloom was caused by an overall increase in nutrient flux into the world oceans. Four of the cores record the bloom's PMAR peak as bimodal, indicating a pulsed increase in phosphorus to the oceans. This suggests that there may have been multiple causes of the biogenic bloom.

(Table 3) Aeolian component of North Pacific pelagic sediments

Isolation and analysis of the eolian component of late Cenozoic pelagic sediments from the North Pacific provides direct information concerning changes in atmospheric circulation. A 50% increase in intensity of both the prevailing westerlies and the tradewinds coincides with increasing pole-to-equator temperature gradients resulting from the onset of northern hemisphere glaciation. At the same time, the mass flux of dust from continents to the North Pacific increased by a factor of 4.5, apparently reflecting significantly increased continental aridity associated with the late Cenozoic glacial ages.

Limits of the Southern Ocean

The knowledge about processes concerning perception and understanding is of paramount importance for designing means of communication like maps and charts. This is especially the case, if one does not want to lose sight of the map-user and if map-design is to be orientated along the map-users needs and preferences in order to improve the cartographic product's usability. A scientific approach to visualization can help to achieve useable results. The insights achieved by such an approach can lead to modes of visualization that are superior to those, which have seemingly proved their value in praxis - so-called "bestpractices" -, concerning their utility and efficiency. This thesis shows this by using the example of visualizing the limits of bodies of waters in the Southern Ocean. After making some introductorily remarks on the chosen mode of problem-solution in chapter one, which simultaneously illustrate the flow of work while working on the problem, in chapter two the relevant information concerning the drawing of limits in the Southern Ocean is outlined. Chapter 3 builds the theoretical framework, which is a multidisciplinary approach to representation. This theoretical framework is based on "How Maps Work" by the American Cartographer MacEachren (1995/2004). His "scientific approach to visualization" is amended and adjusted by the knowledge gained from recent findings of the social sciences where necessary. So, the approach suggested in this thesis represents a synergy of psychology, sociology, semiotics, linguistics, communication theory and cartography. It follows the tradition of interdisciplinary research getting over the boundaries of a single scientific subject. The achieved holistic approach can help to improve the usability of cartographic products. It illustrates on the one hand those processes taking place while perceiving and recognizing cartographic information - so-called bottom-up-processes. On the other hand it illuminates the processes which happen during understanding this information in so-called top-down-processes. Bottom-up- and top-down-processes are interdependent and inseparably interrelated and therefore cannot be understood without each other. Regarding aspects of usability the approach suggested in this thesis strongly focuses on the map-user. This is the reason why the phenomenon of communication gains more weight than in MacEachren's map-centered approach. Because of this, in chapter 4 a holistic approach to communication is developed. This approach makes clear that only the map-user can evaluate the usability of a cartographic product. Only if he can extract the information relevant for him from the cartographical product, it is really useable. The concept of communication is well suited to conceive that. In case of the visualization of limits of bodies of water in the Southern Ocean, which is not complex enough to illustrate all results of the theoretical considerations, it is suggested to visualize the limits with red lines. This suggestion deviates from the commonly used mode of visualization. So, this thesis shows how theory is able to ameliorate praxis. Chapter 5 leads back to the task of fixing limits of the bodies of water in the area of concern. A convention by the International Hydrographic Organization (IHO) states that those limits should be drawn by using meridians, parallels, rhumb lines and bathymetric data. Based on the available bathymetric data both a representation and a process model are calculated, which should support the drawing of the limits. The quality of both models, which depends on the quality of the bathymetric data at hand, leads to the decision that the representation model is better suited to support the drawing of limits.

Table 3.1 Content and composition of air in an ice profile from Camp III i Greenland

The air trapped in freshly formed ice gives information concerning the ice formation processes as weH as concerning severa,l environmental parameters at the time of ice formation. Air arnount, air composition, and the size and form of bubbles may change with time. Possible processes responsible for such changes are discussed. In very cold ice air content and air composition remain almost unchanged. Samples of ancient atmospheric air are therefore very weH preserved in cold ice. In temperate ice changes of the air amount and air composition depend on the intergranular water fiow through the glacier. This waterfiow can be estimated by measuring air amount and air composition in ice sampIes.

Pigments of sediment cores of the Northwest European Continental Margin

In the context of the European OMEX Programme this investigation focused on gradients in the biomass and activity of the small benthic size spectrum along a transect across the Goban Spur from the outer Celtic Sea into Porcupine Abyssal Plain. The effects of food pulses (seasonal, episodic) on this part of the benthic size spectrum were investigated. Sediments sampled during eight expeditions at different seasons covering a range from 200 m to 4800 m water depth were assayed with biochemical bulk measurements: determinations of chloroplastic pigment equivalents (CPE), the sum of chlorophyll a and its breakdown products, provide information concerning the input of phytodetrital matter to the seafloor; phospholipids were analyzed to estimate the total biomass of small benthic organisms (including bacteria, fungi, flagellata, protozoa and small metazoan meiofauna). A new term 'small size class biomass' (SSCB) is introduced for the biomass of the smallest size classes of sediment-inhabiting organisms; the reduction of fluorescein-di-acetate (FDA) was determined to evaluate the potential activity of ester-cleaving bacterial exoenzymes in the sediment samples. At all stations benthic biomass was predominantly composed of the small size spectrum (90% on the shelf; 97-98% in the bathyal and abyssal parts of the transect). Small size class biomass (integrated over a 10 cm sediment column) ranged from 8 g C/m**2 on the shelf to 2.1 g C/m**2 on the adjacent Porcupine Abyssal Plain, exponentially decreasing with increasing water depth. However, a correlation between water depth and SSCB, macrofauna biomass as well as metazoan meiofauna biomass exhibited a significantly flatter slope for the small size classes in comparison to the larger organisms. CPE values indicated a pronounced seasonal cycle on the shelf and upper slope with twin peaks of phytodetrital deposition in mid spring and late summer. The deeper stations seem to receive a single annual flux maximum in late summer. SSCB and heterotrophic activity are significantly correlated to the amount of sediment-bound pigments. Seasonality in pigment concentrations is clearly followed by SSCB and activity. In contrast to macro- and megafauna which integrate over larger periods (months/years), the small benthic size classes, namely bacteria and foraminifera, proved to be the most reactive potential of the benthic communities to any perturbations on short time scales (days/weeks). The small size classes, therefore, occupy a key role in early diagenetic processes.