Seawater carbonate chemistry, and Lithophyllum sp. and Feldmannia spp. coverage and dry weight during experiments, 2009

Climate-driven change represents the cumulative effect of global through local-scale conditions, and understanding their manifestation at local scales can empower local management. Change in the dominance of habitats is often the product of local nutrient pollution that occurs at relatively local scales (i.e. catchment scale), a critical scale of management at which global impacts will manifest. We tested whether forecasted global-scale change [elevated carbon dioxide (CO2) and subsequent ocean acidification] and local stressors (elevated nutrients) can combine to accelerate the expansion of filamentous turfs at the expense of calcifying algae (kelp understorey). Our results not only support this model of future change, but also highlight the synergistic effects of future CO2 and nutrient concentrations on the abundance of turfs. These results suggest that global and local stressors need to be assessed in meaningful combinations so that the anticipated effects of climate change do not create the false impression that, however complex, climate change will produce smaller effects than reality. These findings empower local managers because they show that policies of reducing local stressors (e.g. nutrient pollution) can reduce the effects of global stressors not under their governance (e.g. ocean acidification). The connection between research and government policy provides an example whereby knowledge (and decision making) across local through global scales provides solutions to some of the most vexing challenges for attaining social goals of sustainability, biological conservation and economic development.

San Francisco Coastal System grain size and geochemical data for sand provenance study

Over 150 million cubic meter of sand-sized sediment has disappeared from the central region of the San Francisco Bay Coastal System during the last half century. This enormous loss may reflect numerous anthropogenic influences, such as watershed damming, bay-fill development, aggregate mining, and dredging. The reduction in Bay sediment also appears to be linked to a reduction in sediment supply and recent widespread erosion of adjacent beaches, wetlands, and submarine environments. A unique, multi-faceted provenance study was performed to definitively establish the primary sources, sinks, and transport pathways of beach sized-sand in the region, thereby identifying the activities and processes that directly limit supply to the outer coast. This integrative program is based on comprehensive surficial sediment sampling of the San Francisco Bay Coastal System, including the seabed, Bay floor, area beaches, adjacent rock units, and major drainages. Analyses of sample morphometrics and biological composition (e.g., Foraminifera) were then integrated with a suite of tracers including 87Sr/86Sr and 143Nd/144Nd isotopes, rare earth elements, semi-quantitative X-ray diffraction mineralogy, and heavy minerals, and with process-based numerical modeling, in situ current measurements, and bedform asymmetry to robustly determine the provenance of beach-sized sand in the region.

Alkenone unsaturation index and alkenones in ODP Hole 161-977A

A number of essential elements closely related to each other are involved in the Earth's climatic system. The temporal and spatial distribution of insolation determines wind patterns and the ocean's thermohaline pump. In turn, these last two are directly linked to the extension and retreat of marine and continental ice and to the chemistry of the atmosphere and the ocean. The variability of these elements may trigger, amplify, sustain or globalize rapid climatic changes. Paleoclimatic oscillations have been identified in this thesis by using fossil organic compounds synthesized by marine and terrestrial flora. High sedimentation rate deposits at the Barents and the Iberian peninsula continental margins were chosen in order to estimate the climatic changes on centennial time resolution. At the Barents margin, the sediment recovered was up to 15,000 years old (unit ''a'', from latin ''annos'') (M23258; west of the Bjørnøya island). At the Iberian margin, the sediment cores studied covered a wide range of time spans: up to 115,000 a (MD99-2343; north of the Minorca island), up to 250,000 a (ODP-977A; Alboran basin) and up to 420,000 a (MD01-2442, MD01-2443, MD01-2444, MD01-2445; close to the Tagus abyssal plain). At the northern site, inputs containing marine, continental and ancient reworked organic matter provided a detailed reconstruction of climate history at the time of the final retreat of the Barents ice sheet. At the western Barents continental slope, warm climatic conditions were observed during the early Holocene (~from 8,650 a to 5,240 a ago); in contrast, an apparent long-term cooling trend occurred in the late Holocene (~from 5,240 a to 760 a ago), in consistence with other paleoarchives from northern and southern European latitudes. The Iberian margin sites, which were never covered with large ice sheets, preserved exceptionally complete sequences of rapid events during ice ages hitherto not studied in such great detail: during the last glacial (~from 70,900 a to 11,800 a ago), the second glacial (~from 189,300 a to 127,500 a ago), the third ice age (~from 278,600 a to 244,800 a ago) and the fourth (~from 376,300 a to 337,500 a ago). In this thesis, crucial research questions were brought up concerning the severity of different glacial periods, the intensity and rates of the recorded oscillations and the long distance connections related to rapid climate change. The data obtained provide a sound basis to further research on the mechanisms involved in this rapid climate variability. An essential point of the research was the evidence that, over the past 420,000 a, at the whole Iberian margin, warm and stable long periods similar to the Holocene always ended abruptly in few centuries after a gradual deterioration of climate conditions. The detailed estimate of past climate variability provides clues to the natural end of the present warm period. Returning to an ice age in European lands would be exacerbated by a number of factors: a lack of differential solar heating between northern and southern north Atlantic latitudes, enhanced evaporation at low latitudes, and an increase in snowfall or iceberg discharges at northern regions. It must be emphasized that all climatic oscillations observed in this thesis were caused by forces of nature, i.e. the last two centuries were not taken into consideration.

Isotopic ratios and ion composition of massive ground ice on Herschel Island

Herschel Island in the southern Beaufort Sea is a push moraine at the northwestern-most limit of the Laurentide Ice Sheet. Stable water isotope (d18O, dD) and hydrochemical studies were applied to two tabular massive ground ice bodies to unravel their genetic origin. Buried glacier ice or basal regelation ice was encountered beneath an ice-rich diamicton with strong glaciotectonic deformation structures. The massive ice isotopic composition was highly depleted in heavy isotopes (mean d18O: -33 per mil; mean dD: -258 per mil), suggesting full-glacial conditions during ice formation. Other massive ice of unknown origin with a very large d18O range (from -39 to -21 per mil) was found adjacent to large, striated boulders. A clear freezing slope was present with progressive depletion in heavy isotopes towards the centre of the ice body. Fractionation must have taken place during closed-system freezing, possibly of a glacial meltwater pond. Both massive ground ice bodies exhibited a mixed ion composition suggestive of terrestrial waters with a marine influence. Hydrochemical signatures resemble the Herschel Island sediments that are derived from nearshore marine deposits upthrust by the Laurentide ice. A prolonged contact between water feeding the ice bodies and the surrounding sediment is therefore inferred.

(Table 1) Soil description of pits dug in coastal, inland and higland Antarctic Dry Valleys

In the past few years, it has become increasingly apparent that perchlorate (ClO4-) is present on all continents, except the polar regions where it had not yet been assessed, and that it may have a significant natural source. Here, we report on the discovery of perchlorate in soil and ice from several Antarctic Dry Valleys (ADVs) where concentrations reach up to 1100/µg/kg. In the driest ADV, perchlorate correlates with atmospherically deposited nitrate. Far from anthropogenic activity, ADV perchlorate provides unambiguous evidence that natural perchlorate is ubiquitous on Earth. The discovery has significant implications for the origin of perchlorate, its global biogeochemical interactions, and possible interactions with the polar ice sheets. The results support the hypotheses that perchlorate is produced globally and continuously in the Earth's atmosphere, that it typically accumulates in hyperarid areas, and that it does not build up in oceans or other wet environments most likely because of microbial reduction on a global scale.

Victoria Land Antarctica Pb and Ba concentrations and Pb isotope ratios 1872-1994 CE

Pb and Ba concentrations and Pb isotopic compositions are reported for firn core and snow pit samples from Victoria Land, Antarctica, dating from 1872 AD to 1994 AD. From variations in Pb/Ba ratios and Pb isotopic compositions, two periods of major Pb enhancements were identified, from 1891 to 1908 AD and from 1948 to 1994 AD. The earlier pollution event is attributed to Pb emissions from non-ferrous metal production and coal combustion in the Southern Hemisphere and is in excellent agreement with coincident pollution inputs reported in firn/ice cores from two other regions of Antarctica, at Coats Land and Law Dome. Using Pb isotopic systematics, it was calculated that ~50% of Pb deposited in Victoria Land in 1897 originated from anthropogenic emission sources. The more recent period of Pb enhancements, from 1948 to 1994 AD, corresponds to the introduction and widespread use of gasoline alkyl Pb additives in automobiles in the Southern Hemisphere, with anthropogenic Pb inputs averaging 60% of total Pb but with large uncertainty. Intra- and inter-annual variations in Pb concentrations and isotopic compositions were evaluated in snow pits samples corresponding to the period 1991-1994. Substantial variations in Pb/ Ba and 206Pb/207Pb ratios were detected but the absence of a regular seasonal pattern for these parameters suggests that the transport and deposition of aerosols to the Antarctic ice sheet are complex and vary from year to year.

Interpolated maps of pollen percentages in Europe over the last 15,000 years

Aim Palaeoecological reconstructions document past vegetation change with estimates of rapid rates of changing species distribution limits that are often not matched by model simulations of climate-driven vegetation dynamics. Genetic surveys of extant plant populations have yielded new insight into continental vegetation histories, challenging traditional interpretations that had been based on pollen data. Our aim is to examine an updated continental pollen data set from Europe in the light of the new ideas about vegetation dynamics emerging from genetic research and vegetation modelling studies. Location Europe Methods: We use pollen data from the European Pollen Database (EPD) to construct interpolated maps of pollen percentages documenting change in distribution and abundance of major plant genera and the grass family in Europe over the last 15,000 years. Results: Our analyses confirm high rates of postglacial spread with at least 1000 metres per year for Corylus, Ulmus and Alnus and average rates of 400 metres per year for Tilia, Quercus, Fagus and Carpinus. The late Holocene expansions of Picea and Fagus populations in many European regions cannot be explained by migrational lag. Both taxa shift their population centres towards the Atlantic coast suggesting that climate may have played a role in the timing of their expansions. The slowest rates of spread were reconstructed for Abies. Main conclusions: The calculated rates of postglacial plant spread are higher in Europe than those from North America, which may be due to more rapid shifts in climate mediated by the Gulf Stream and westerly winds. Late Holocene anthropogenic land use practices in Europe had major effects on individual taxa, which in combination with climate change contributed to shifts in areas of abundance and dominance. The high rates of spread calculated from the European pollen data are consistent with the common tree species rapidly tracking early Holocene climate change and contribute to the debate on the consequences of global warming for plant distributions.

Winter sea surface temperature reconstruction from planktic foraminiferal transfer functions in the northeastern Arabian Sea over the last two millennia

The Indian monsoon system is an important climate feature of the northern Indian Ocean. Small variations of the wind and precipitation patterns have fundamental influence on the societal, agricultural, and economic development of India and its neighboring countries. To understand current trends, sensitivity to forcing, or natural variation, records beyond the instrumental period are needed. However, high-resolution archives of past winter monsoon variability are scarce. One potential archive of such records are marine sediments deposited on the continental slope in the NE Arabian Sea, an area where present-day conditions are dominated by the winter monsoon. In this region, winter monsoon conditions lead to distinctive changes in surface water properties, affecting marine plankton communities that are deposited in the sediment. Using planktic foraminifera as a sensitive and well-preserved plankton group, we first characterize the response of their species distribution on environmental gradients from a dataset of surface sediment samples in the tropical and sub-tropical Indian Ocean. Transfer functions for quantitative paleoenvironmental reconstructions were applied to a decadal-scale record of assemblage counts from the Pakistan Margin spanning the last 2000?years. The reconstructed temperature record reveals an intensification of winter monsoon intensity near the year 100 CE. Prior to this transition, winter temperatures were >1.5°C warmer than today. Conditions similar to the present seem to have established after 450 CE, interrupted by a singular event near 950 CE with warmer temperatures and accordingly weak winter monsoon. Frequency analysis revealed significant 75-, 40-, and 37-year cycles, which are known from decadal- to centennial-scale resolution records of Indian summer monsoon variability and interpreted as solar irradiance forcing. Our first independent record of Indian winter monsoon activity confirms that winter and summer monsoons were modulated on the same frequency bands and thus indicates that both monsoon systems are likely controlled by the same driving force.

(Table 1) Major element composition of core 5022-2CP, Laguna Potrok Aike, southern Patagonia

Total organic carbon, total inorganic carbon, biogenic silica content and total organic carbon/total nitrogen ratios of the Laguna Potrok Aike lacustrine sediment record are used to reconstruct the environmental history of south-east Patagonia during the past 51 ka in high resolution. High lake level conditions are assumed to have prevailed during the Last Glacial, as sediments are carbonate-free. Increased runoff linked to permafrost and reduced evaporation due to colder temperatures and reduced influence of Southern Hemispheric Westerlies (SHW) may have caused these high lake levels with lake productivity being low and organic matter mainly of algal or cyanobacterial origin. Aquatic moss growth and diatom blooms occurred synchronously with southern hemispheric glacial warming events such as the Antarctic A-events, the postglacial warming following the LGM and the Younger Dryas chronozone. During these times, a combination of warmer climatic conditions with related thawing permafrost could have increased the allochthonous input of nutrients and in combination with warmer surface waters increased aquatic moss growth and diatom production. The SHW were not observed to affect southern Patagonia during the Last Glacial. The Holocene presents a completely different lacustrine system because (a) permafrost no longer inhibits infiltration nor emits meltwater pulses and (b) the positioning of the SHW over the investigated area gives rise to strong and dry winds. Under these conditions total organic carbon, total organic carbon/total nitrogen ratios and biogenic silica cease to be first order productivity indicators. On the one hand, the biogenic silica is influenced by dissolution of diatoms due to higher salinity and pH of the lake water under evaporative stress characterizing low lake levels. On the other hand, total organic carbon and total organic carbon/total nitrogen profiles are influenced by reworked macrophytes from freshly exposed lake level terraces during lowstands. Total inorganic carbon remains the most reliable proxy for climatic variations during the Holocene as high precipitation of carbonates can be linked to low lake levels and high autochthonous production. The onset of inorganic carbon precipitation has been associated with the southward shift of the SHW over the latitudes of Laguna Potrok Aike. The refined age-depth model of this record suggests that this shift occurred around 9.4 cal. ka BP.

Tab. 1: Proportion of glacial quartz grains contained in the deposits

The Yari-Hotaka Mountain Range is one of the most famous formerly-glaciated areas of Japan. Many glacial landforms remain in three neighbouring U-shaped valleys, named Yarisawa, Yokoo and Migimata. Moraines and outwash terraces can be classified into four groups according to their location and to the amount of glacial quartz grains contained in the deposits. A glaciation is proved for other parts of the Northern Japanese Alps before 100 000 years B.P., but not for the Yari-Hotaka Mountain Range, because the corresponding glacial landforms cannot be found here. The oldest known Ichinomata stage before and after 60 000 years B.P. corresponds to the Yokoo glacial which is proved wirhin the whole Japanese Alps. The three younger stages, Babadaira stage (before 30 000 years B.P.), Yarisawa stage I (about 30000 years B.P.) and Yarisawa stage II (about 15000 years B.P.), belong to the Karasawa glacial. About 10 000 years B.P. the glaciers melted away. At all times the relief-influence was especially important for Ihe mass-balances of Japanese glaciers. Wind-drifted snow from the west-exposed windward slopes to the slopes in eastern (lee) exposition, and a voluminous snow accumulation by avalanches from the high rocky walls onto the glacier surfaces beneath, caused very low situated glaciers as well as low equilibrium-lines. In most cases the snow-lines were situated 100 m or more above the equilibrium-lines. During the Ichinomata stage the snow-line reached an altitude of 2400-2450 m. It rose about 100 m to the Babadaira stage, 300 m to Yarisawa stage I and about 450 m to Yarisawa stage II. At present the snow-line is situated above the Northern Japanese Alps at over 4000 m. Therefore only perennial snow-patches exist. If the snow-line would go down by a few hundred meters, this region would be highly interesting Ifor studies on the beginning of mountain glaciation.

Annotated record of the detailed examination of Mn deposits from C.S.S. Hudson Cruise 19 (1967) stations

The Bedford Institute of Oceanography provided ship time on the C.S.S. Hudson during the B.I.0. 1967 Metrology and IODAL Cruise for surveying two separate bottom features in the North Atlantic; the Flemish Cap and the San Pablo Seamount one of the Kelvin Seamounts (also known as the New England Seamounts) about 400 miles SSE of Halifax, Nova Scotia. Underwater photography, dredging, and drilling showed San Pablo seamount to have a very considerable covering of manganese deposit, which may be recoverable by mining. San Pablo Seamount was surveyed and sampled; good hauls were made both on the top and on the slopes, at various depths from 500-1000 fathoms; in all cases samples of an unusual stratified manganese-iron ore were recovered. In the hope of gaining additional information in the immediate sample area, one of the dredges had been previously modified to accommodate underwater photographic equipment. X-ray chemical analyses indicate that the ore contains 20 to 25 per cent MnO2, with similar amounts of Fe2O3. Since bottom photographs indicate that these deposits form a continuous cover 1 foot to 3 feet thick over most of the seamount, it is estimated that there are ore reserves in the order of 10 to 30 M tons above 1,000 fathoms.

Ecological classification of Herschel Island based on supervised classification of multispectral satellite imagery

Permafrost landscapes experience different disturbances and store large amounts of organic matter, which may become a source of greenhouse gases upon permafrost degradation. We analysed the influence of terrain and geomorphic disturbances (e.g. soil creep, active-layer detachment, gullying, thaw slumping, accumulation of fluvial deposits) on soil organic carbon (SOC) and total nitrogen (TN) storage using 11 permafrost cores from Herschel Island, western Canadian Arctic. Our results indicate a strong correlation between SOC storage and the topographic wetness index. Undisturbed sites stored the majority of SOC and TN in the upper 70 cm of soil. Sites characterised by mass wasting showed significant SOC depletion and soil compaction, whereas sites characterised by the accumulation of peat and fluvial deposits store SOC and TN along the whole core. We upscaled SOC and TN to estimate total stocks using the ecological units determined from vegetation composition, slope angle and the geomorphic disturbance regime. The ecological units were delineated with a supervised classification based on RapidEye multispectral satellite imagery and slope angle. Mean SOC and TN storage for the uppermost 1?m of soil on Herschel Island are 34.8 kg C/m**2 and 3.4 kg N/m**2, respectively.

Annotated record of the detailed examination of Mn deposits from DSDP Site 159, Leg 16 (Cores 16-159-6 and 16-159-12)

DSDP 159 is one of a series of sites in the eastern equatorial Pacific on the west flank of the East Pacific Rise. It was selected by the Pacific Site Selection Panel on the premise that if hydrothermal processes on the crest of the East Pacific Rise supply the transition metals, a broad zone of such deposits should be present immediately above basement over the entire flank of the Rise.

Annotated record of the detailed examination of Mn deposits from DSDP Site 20, Leg 3 (Holes 3-20, 3-20A and 3-20C)

Prior to arrival on this site, the only survey data available was from the Vema-20 crossing of the area. The recommended site location was over a relatively smooth valley in the bottom topography at about 4750 meters (15,580 feet) depth (uncorrected), about 10 kilometers wide E-W between peaks (or ridges) on either side. Sediment thickness was unknown. The center of the valley is near the peak of a wide (40 to 50 kilometers) positive magnetic anomaly, identified as Magnetic Anomaly 30 in the hypothesized geomagnetic time scale with an age of 72 million years.

Annotated record of the detailed examination of Mn deposits from DSDP Site 156, Leg 16 (Core 16-156-1)

This site was accidentally spudded on a small basement pinnacle and was abandoned when hard rock was reached within a few meters from the surface. The section penetrated consisted of coarse winnowed calcareous sand over thin chalk ooze resting on a hard crust of ferromanganese oxide presumably covering basalt.