Analyses of a Holocene soil/loess sequence in Southern Siberia

We conducted a high-resolution study of a unique Holocene sequence of wind-blown sediments and buried soils in Southern Siberia, far from marine environment influences. This was accomplished in order to assess the difference between North Atlantic marine and in-land climate variations. Relative wind strength was determined by grain size analyses of different stratigraphic units. Petromagnetic measurements were performed to provide a proxy for the relative extent of pedogenesis. An age model for the sections was built using the radiocarbon dating method. The windy periods are associated with the absence of soil formation and relatively low values of frequency dependence of magnetic susceptibility (FD), which appeared to be a valuable quantitative marker of pedogenic activity. These events correspond to colder intervals which registered reduced solar modulation and sun spot number. Events, where wind strength was lower, are characterized by soil formation with high FD values. Spectral analysis of our results demonstrates periodic changes of 1500, 1000 and 500 years of relatively warm and cold intervals during the Holocene of Siberia. We presume that the 1000 and 500 year climatic cycles are driven by increased solar insolation reaching the Earth surface and amplified by other still controversial mechanisms. The 1500 year cycle associated with the North Atlantic circulation appears only in the Late Holocene. Three time periods - 8400-9300 years BP, 3600-5100 years BP, and the last ~250 years BP - correspond to both the highest sun spot number and the most developed soil horizons in the studied sections

Spectral reflectance of ODP Leg 178 holes

The routine use of spectrophotometry on the sediment surfaces of archive halves of each section during the onboard sedimentological core description process is a great stride toward development of real-time noninvasive characterization of deep-sea sediments. Spectral reflectance data have been used so far for mineral composition studies as well as for lithostratigraphic correlation between sites (Balsam and Deaton, 1991; Balsam et al., 1997; Mix et al., 1995; Ortiz et al., 1999). Their results demonstrate that spectrophotometry can estimate CaCO3 content by using the 4.65-, 5.25-, and 5.55-µm wavelength spectrums. A detailed overview of various other noninvasive methods is given in Ortiz and Rack (1999). The purpose of this study is to test whether spectrophotometry in the visible band can be used as a tool to gather further information about grain-size variation, sorting, compaction, and porosity, which are directly linked to the sedimentation process. From remote sensing data analyses, it is known that diffuse spectral reflectance data in the visible band in the wavelength window of 7.0-6.5 µm are sensitive to grain-size variations. It appears that a relationship between grain size and signal absorption exists only in this wavelength window. (e.g., Clark, 1999; Gaffey, 1986; Gaffey et al., 1993). Variations in grain size during a sedimentation process are linked to depositional energy, which affects sorting, compaction, and porosity of sediment deposits. As an example, we study here the spectrophotometric data of the sedimentary sequence of Hole 1098C, which was deposited under widely varying environmental conditions. Alternating turbidite and finely laminated sediments were recovered from Hole 1098C. The turbidites are related to a high depositional energy environment; the finely laminated sediments are related to a low depositional energy environment. Data from Hole 1098C were therefore used to test whether the spectral reflectance data can provide a proxy for these different depositional environments.

Sedimentary data from the Semlac loess-paleosol sequence

The volumetric magnetic susceptibility was measured at frequencies of 300 and 3000 Hz in a static field of 300 mA/m using a Magnon International VSFM in the Laboratory for Environmental- and Palaeomagnetism at the University of Bayreuth. The magnetic susceptibility was mass-normalised. The frequency dependence was calculated as MSfd = (MSlf - MShf) / MSlf *100 [%]. A spectrophotometer (Konica Minolta CM-5) was used to determine the colour of dried and homogenised sediment samples by detecting the diffused reflected light under standardised observation conditions (2° Standard Observer, Illuminant C). Colour spectra were obtained in the visible range (360 to 740 nm), in 10 nm increments, and the spectral data was converted into the Munsell colour system and the CIELAB Colour Space (L*a*b*, CIE 1976) using the Software SpectraMagic NX (Konica Minolta). The measurement of the particle size was conducted by using a Laser Diffraction Particle Size Analyzer (Beckman Coulter LS 13 320 PIDS) and by calculating the mean diameters of the particles within a size range of 0.04 - 2000 µm. Each sample was measured two times in two different concentrations to increase accuracy. Finally all measurements with reliable obscuration (8 - 12 %) were averaged.

Coral reef habitat maps derived from a high-spatial-resolution multi-spectral satellite image using object based image analysis

Coral reef maps at various spatial scales and extents are needed for mapping, monitoring, modelling, and management of these environments. High spatial resolution satellite imagery, pixel <10 m, integrated with field survey data and processed with various mapping approaches, can provide these maps. These approaches have been accurately applied to single reefs (10-100 km**2), covering one high spatial resolution scene from which a single thematic layer (e.g. benthic community) is mapped. This article demonstrates how a hierarchical mapping approach can be applied to coral reefs from individual reef to reef-system scales (10-1000 km**2) using object-based image classification of high spatial resolution images guided by ecological and geomorphological principles. The approach is demonstrated for three individual reefs (10-35 km**2) in Australia, Fiji, and Palau; and for three complex reef systems (300-600 km**2) one in the Solomon Islands and two in Fiji. Archived high spatial resolution images were pre-processed and mosaics were created for the reef systems. Georeferenced benthic photo transect surveys were used to acquire cover information. Field and image data were integrated using an object-based image analysis approach that resulted in a hierarchically structured classification. Objects were assigned class labels based on the dominant benthic cover type, or location-relevant ecological and geomorphological principles, or a combination thereof. This generated a hierarchical sequence of reef maps with an increasing complexity in benthic thematic information that included: 'reef', 'reef type', 'geomorphic zone', and 'benthic community'. The overall accuracy of the 'geomorphic zone' classification for each of the six study sites was 76-82% using 6-10 mapping categories. For 'benthic community' classification, the overall accuracy was 52-75% with individual reefs having 14-17 categories and reef systems 20-30 categories. We show that an object-based classification of high spatial resolution imagery, guided by field data and ecological and geomorphological principles, can produce consistent, accurate benthic maps at four hierarchical spatial scales for coral reefs of various sizes and complexities.