UPLAND EROSION MODELING WITH CASC2D-SED

1 INTRODUCTION Erosion and sedimentation embody the processes of detachment, transport, and deposition of soil particles. Erosion and subsequent deposition can cause major problems. Erosion reduces productivity of cropland, sediment degrades water quality and may carry soil adsorbed polluting chemicals. Deposition in irrigation canals, stream channels and reservoirs reduces structural capacity and requires costly removal. Ideally, an erosion model should describe the physical processes…     

Cyanobacterial blooms in estuarine ecosystems: characteristics and effects on Laeonereis acuta (Polychaeta, Nereididae)

In January of 2003, a cyanobacterial bloom in the Patos' Lagoon (Southern Brazil) (32 degrees 05'S-52 degrees 12'W) was observed. Water samples were taken to identify the composition and abundance of the bloom, as well as the occurrence of toxins. The effects of this occurrence on the estuarine worm Laeonereis acuta (Polychaeta, Nereididae) was also evaluated. Predominance of cyanobacteria, particularly Anabaena trichomes ( approximately 2.5.10(6) individuals per liter) was observed, and low concentrations of microcystins and anticholinesterasic toxins were detected. Augmented levels of lipid hydroperoxides (LPO) and glutathione-S-transferase activity, and lowering of total protein content were also observed in organisms collected during the bloom event. Although non-toxic, the cyanobacterial bloom could augment the cycle of hyper-oxygenation and hypoxia in the water. During hyperoxia, L. acuta, an oxyconformer, should consume more oxygen, thus augmenting the rate of reactive oxygen species generation. A repeated cycle of hyper-oxygenation and hypoxia would finally induce oxidative stress, as evidenced by the high levels of LPO and glutathione-S-transferase activity.     

Detection of Extended Thermal Infrared Emission around the Vega-like Source HD 141569

We report the detection of extended IR emission at 10.8 and 18.2 μm around the Vega-like source HD 141569. Mid-IR imaging with OSCIR on Keck II shows emission from dust extending out to 100 AU from the B9.5 Ve star. Our modeling of the dust places an upper limit of approximately 2 μm on the diameter of the mid-IR-emitting particles if they are Mie spheres of astronomical silicates. Comparison of our mid-IR images to the near-IR (1.1 μm) NICMOS images of HD 141569 (Weinberger et al. 1999) shows that the mid-IR emission originates at smaller distances from the star than the scattered near-IR light, as also previously observed for the archetype Vega-like source beta Pictoris.     

PETROLOGY AND AGE OF THE KINNAR KAILAS GRANITE:EVIDENCES FOR AN ORDOVICIAN POST-OROGENIC EXTENSION IN THE HIGHER HIMALAYAN CRYSTALLINE, SUTLEJ, INDIA.

PETROLOGY AND AGE OF THE KINNAR KAILAS GRANITE:EVIDENCES FOR AN ORDOVICIAN POST-OROGENIC EXTENSION IN THE HIGHER HIMALAYAN CRYSTALLINE, SUTLEJ, INDIA     

Evaluation of the contamination of platinum in estuarine and coastal sediments (Tagus Estuary and Prodelta, Portugal)

Platinum contamination in estuarine and coastal sediments has been evaluated in three cores collected from the Tagus Estuary and Prodelta shelf sediments. Elevated concentrations, up to 25-fold enrichment compared to background values, were found in the upper layers of the estuarine sediments. The degree of Pt enrichment in the estuarine sediments varied depending on the proximity to vehicular traffic sources, with a maximum concentration of 9.5 ng g⁻¹. A considerable decrease of Pt concentrations with depth indicated the absence of significant contamination before the introduction of catalytic converters in automobiles. Platinum distribution in the Tagus Prodelta shelf sediment core showed no surface enrichment; instead a sub-surface maximum at the base of the mixed layer suggested the possibility of post-depositional mobility, thereby blurring the traffic-borne contamination signature in coastal sediments.     

Assessing food web dynamics and relative importance of organic matter sources for fish species in two Portuguese estuaries: a stable isotope approach

Stable carbon and nitrogen isotopes (δ13C, δ1?N) were used to analyse food web dynamics of two of the main estuaries of the Portuguese coast: Tejo and Mira. The ultimate sources of organic matter supporting production of some of the most abundant and commercially important fish species were determined; and seasonal, inter- and intra- estuarine differences in the trophic relations among producers and consumers were identified. Stable isotope analysis was performed in different producers, primary consumers (main prey items for fish) and fish species (Solea solea, Solea senegalensis, Pomatoschistus microps, Dicentrarchus labrax, Liza ramada, Diplodus vulgaris and Atherina presbyter) of two areas in each estuary, in July and October 2009. Model calculations showed that the main prey for the fish species in the Tejo estuary used mostly salt marsh-derived organic matter as nutritional sources, with no marked differences between the sampled months. Trophic levels of fish species from the same estuary differed at multiple scales: inter-species, seasonally and spatially (both between and within estuaries). Significant differences in isotopic composition of fish species were more pronounced spatially (between the two sampled areas in the estuary) than seasonally (between sampled months). Trophic relationships in both estuaries demonstrated that organic matter is transferred to higher trophic positions mainly through benthic pathways. This shows the flexibility of these species to share resources and to exploit temporary peaks in prey populations. The present results showed that extensive disturbance in intertidal habitats from both estuaries may potentially change the balance of organic matter in the base of these complex food webs.     

Textural and geochemical characteristics of late Pleistocene to Holocene fine-grained deep-sea sediment cores(GM6 and GM7),recovered from southwestern Gulf of Mexico

Texture, mineralogy, geochemistry, and ~(14)C ages of two deep-sea sediment cores(GM6 and GM7) recovered in the southwestern Gulf of Mexico were investigated to infer their provenance and depositional condition. The sediments are enriched in fine-grained silt and clay and poor in sand content. Mineralogically, the sediments consist of quartz,calcite, smectite, and kaolinite. Based on the ~(14)C data, the age of the GM6 and GM7 sediment cores were calculated as23,615 cal yrs. BP and 19,007 cal yrs. BP, respectively. The weathering indices such as chemical index of alteration(CIA),chemical index of weathering(CIW), and plagioclase index of alteration(PIA) in GM6(56-69, 60-74, and 61-73,respectively) and GM7(54-69, 57-76, and 55-74, respectively) cores revealed a moderate-to-high intensity of weathering. The rare earth element(REE) patterns suggested that the sediments were derived mostly by the weathering of intermediate rocks, exposed along the coastal regions of the Gulf of Mexico. The trace elemental ratios like V/Cr(2),Ni/Co(2), and Cu/Zn(1), authigenic uranium content(1), and Ce anomaly(Ce/Ce~* ≤ 1) suggested that the sediments were deposited under an oxic condition, which was also revealed by the benthic foraminiferal assemblages throughout the GM6 and GM7 sediment cores.     

Effect of climate change on drinking water supply in Santiago de Chile

Climate change is likely to increase the occurrence of floods and flashfloods that affect Santiago de Chile's drinking water supply system throughout the 21st century. A relationship between flashfloods in the Maipo River--Santiago's main raw water source, drainage area in the Maipo Alto Sub Basin and precipitation 48 hours previous to the event was found. Despite having legal guidelines to guarantee continuity and stability in water supply, Chilean law does not specify the maximum admissible magnitude of an event. A 12% drop of average monthly flow at Maipo en El Manzano Station was estimated for the 2035-2065 period due to climate change, meaning water suppliers would not be able to meet 90% monthly water supply security, required by Chilean law. Water suppliers would need to increase their current allotted quota of the Maipo River, from 24.5% to a percentage between 26% and 30% to comply. If the 0 °C isotherm keeps increasing its elevation through the 21st century, more intense floods could occur because of additional drainage area granted by the elevation of the snow line, even if precipitation does not suffer a significant change. In order to withstand a five day turbidity event, 2 m 3 /s of groundwater, or any non river source, should be temporarily incorporated to the emergency drinking water production.     

海水盐度对外来物种沙筛贝摄食率的影响

外来物种沙筛贝(Mytilopsis sallei)是一种滤食性软体动物双壳类,它有着很快的生长速度和很强的摄食能力.为了探索沙筛贝在不同盐度下对微藻的摄食能力,采用颗粒计数仪,测定了沙筛贝在15、20、25、30、35等5个盐度梯度下对等鞭金藻(Isochrysis galbana)和小球藻(Chlorella vulgaris)的摄食率,比较了不同沙筛贝个体大小对小球藻的摄食率.结果表明,沙筛贝对等边金藻和小球藻的摄食率均在盐度25时达到最大,分别为3.42×104cells/(ind.h)和6.72×104cells/(ind.h).沙筛贝对等边金藻的摄食率随时间推移而降低,一是因为沙筛贝摄食率随着藻类密度的降低而减小,二是当海水盐度下降,沙筛贝渗透压改变,导致了进入其外套腔的海水体积的减少,从而摄食率也减少.个体较大(壳长2.8～3.5 cm)的沙筛贝对小球藻的摄食率明显高于个体较小(壳长1.7～2.4 cm)的沙筛贝的摄食率,这与其他贝类的研究结果是一致的.     

Fish discards management: pollution levels and best available removal techniques

Fish discards and by-catch issues are highly topical subjects that are permanently under a social focus. Two main approaches are being considered to address this discard problem: reducing the by-catch and increasing by-catch utilization. Interest in increased by-catch valorization may arise from a greater demand for fish products, such as the development of new markets for previously discarded species, the use of low-value specimens for aquaculture or the creation of value-added fish products for the food, pharmaceutical or cosmetic industries. However, contaminants present in fish discards may be transferred to their valorized products, leading to possible long-term bioaccumulation and subsequent adverse health effects. In this valorization framework, the aim is to promote responsible and sustainable management of marine resources. The pollutant levels in catches from European fisheries and the best available decontamination techniques for marine valorized discards/by-products are compiled and analyzed in this work.