Climatic and anthropogenic influence on the stable isotope record from bulk carbonates and ostracodes in Lake Neuchatel, Switzerland, during the last two millennia

Lake Neuchatel is a medium sized, hard-water lake, lacking varved sediments, situated in the western Swiss Lowlands at the foot of the Jura Mountains. Stable isotope data (delta(18)O and delta(13)C) from both bulk carbonate and ostracode calcite in an 81 cm long, radiocarbon-dated sediment core represent the last 1500 years of Lake Neuchatel's environmental history. Comparison between this isotopic and other palaeolimnologic data (mineralogical, geochemical, palynological, etc.) helps to differentiate between anthropogenic and natural factors most recently affecting the lake. An increase in lacustrine productivity (450-650AD ca), inferred from the positive trend in delta(13)C values of bulk carbonate, is related to medieval forest clearances and the associated nutrient budget changes. A negative trend in both the bulk carbonate and ostracode calcite delta(18)O values between approximately 1300 and 1500AD, is tentatively interpreted as due to a cooling in mean air temperature at the transition from the Medieval Warm Period to the Little Ice Age. Negative trends in bulk carbonate delta(18)O and delta(13)C values through the uppermost sediments, which have no equivalent in ostracode calcite isotopic values, are concomitant with the recent onset of eutrophication in the lake. Isotopic disequilibrium during calcite precipitation, probably due to kinetic factors in periods of high productivity is postulated as the mechanism to explain the associated negative isotopic trends, although the effect of a shift of the calcite precipitation towards the warmer months cannot be excluded.

Multiple processes regulate long-term population dynamics of sea urchins on Mediterranean rocky reefs

We annually monitored the abundance and size structure of herbivorous sea urchin populations (Paracentrotus lividus and Arbacia lixula) inside and outside a marine reserve in the Northwestern Mediterranean on two distinct habitats (boulders and vertical walls) over a period of 20 years, with the aim of analyzing changes at different temporal scales in relation to biotic and abiotic drivers. P. lividus exhibited significant variability in density over time on boulder bottoms but not on vertical walls, and temporal trends were not significantly different between the protection levels. Differences in densities were caused primarily by variance in recruitment, which was less pronounced inside the MPA and was correlated with adult density, indicating density-dependent recruitment under high predation pressure, as well as some positive feedback mechanisms that may facilitate higher urchin abundances despite higher predator abundance. Populations within the reserve were less variable in abundance and did not exhibit the hyper-abundances observed outside the reserve, suggesting that predation effects maybe more subtle than simply lowering the numbers of urchins in reserves. A. lixula densities were an order of magnitude lower than P. lividus densities and varied within sites and over time on boulder bottoms but did not differ between protection levels. In December 2008, an exceptionally violent storm reduced sea urchin densities drastically (by 50% to 80%) on boulder substrates, resulting in the lowest values observed over the entire study period, which remained at that level for at least two years (up to the present). Our results also showed great variability in the biological and physical processes acting at different temporal scales. This study highlights the need for appropriate temporal scales for studies to fully understand ecosystem functioning, the concepts of which are fundamental to successful conservation and management.

Project AWARE 2005 Little Sioux River

Summary of Project AWARE 2005, a river cleanup held on the Little Sioux River.

09012-009 Little River Lake Watershed Final Report

Little River Lake watershed is a 13,305 acre subwatershed of Little River. The 788 acre lake was listed as a 303d impaired water body in 2008 due to elevated turbidity and algae levels. The Decatur SWCD has prioritized water quality protection efforts within the Little River Lake watershed because 1) portions of this watershed has been identified as the primary contributor of sediment and nutrients to Little River Lake, which provides an essential source of drinking water for Decatur County and the Southern Iowa Rural Water Association; 2) the watershed provides exemplary education and project interpretation opportunities due to its proximity to Little River Lake Recreation Area, and 3) by using targeted and proven soil conservation practices to address water quality deficiencies the probability of successfully attenuating soil erosion and ameliorating water quality impairments is enhanced. The specific goals of this proposal are to: 1. reduce annual sediment, and phosphorous delivery to the lake by 11,280 tons and 14,664 lbs., respectively, via applications of conservation practices on targeted agricultural land; 2. delist the lake as an EPA 303d impaired water body via water quality enhancement; 3. obtain a “Full Support” status for the lake’s aquatic life and recreational use; 4. reduce potable water treatment costs (minimum 50% cost reduction) associated with high suspended solid levels; and 5. restore a viable sport-fish population, thereby bolstering tourism and the economy. To achieve timely project implementation the Decatur SWCD has cooperated with the IDNR Watershed Improvement Section, Fisheries Bureau, and IDALS-DSC to assess extant water quality and watershed conditions, coalesced a diverse team of committed partners and secured matching funding from multiple sources.

07017-006 Little Clear Lake Watershed Final Report

Little Clear Lake is a 162 acre natural lake located in the western part of Pocahontas County. The lake has a 375 acre watershed that is gently rolling with nearly 84% of the watershed in row crop production. The lake is listed on the Iowa DNR’s impaired waters list due to nutrients, siltation and exotic species (purple loosestrife). These impairments have been verified with in-lake monitoring and landowner conversations as well as watershed modeling. The watershed models estimates that the average sheet and rill erosion is 1.74 tons/acre/year and sediment delivery is .12 tons/acre/year with a total of 44 tons/year being delivered to Little Clear Lake. The goal of the Little Clear Lake Watershed Protection Plan is to (1) reduce sediment delivery to Little Clear Lake by 60%, or 26.5 tons annually, by installing best management practices within the watershed. Doing this will control nearly 100% of the of the lake’s drainage area; and (2) initiate an information and education campaign for residents within the Little Clear Lake watershed which will ultimately prepare the residents and landowners for future project implementation. In an effort to control sediment and nutrient loading the Little Clear Lake Watershed Protection Plan has included 3 sediment catch basin sites and 5 grade stabilization structures, which function to stabilize concentrated flow areas.

05002-001 Little Pony Creek Watershed Final Report

Farmers Creek is a moderately flowing stream that winds through seventeen miles of central Jackson County, encompassing a watershed area of 30,590 acres. Due to nutrient loading and sedimentation, the stream was placed on Iowa’s 303(d) List of Impaired Waters in 2002. A three year grant project was initiated in January 2005 to reduce both sediment delivery and phosphorus levels by 40% in critical areas along the stream corridor. Over thirty-five BMP’s were started in the first nine months of this project. Funding through WIRB is being requested specifically for streambank stabilization and protection projects not covered by other cost-share programs. Innovative project designs and techniques will be installed and act as demonstration sites. Projects may include jetties, weirs, cedar revetments, cattle crossings, and fencing. To assist in excluding cattle from the stream, watering systems such as slingpumps, pasture pumps, or water rams will be installed, in conjunction with filter strips and riparian buffers.

1240-017 Little Bear Creek Watershed Final Report

Little Bear Creek is a 21.79 mile Class A1 and B (WW2) warm water stream that encompasses approximately 29,202 acres in northern Poweshiek County. The lower 8.4 mile segment is listed as biologically impaired on both the IDNR 2008 303(d) list and 2010 303(d) draft list. A RASCAL assessment and landowner survey was completed through a development grant in 2011, and these assessments indicate that erosion and sediment delivery from cropland, lack of adequate buffers along the stream channel, and streambank conditions contribute significant sediment delivery to the stream, likely resulting in the impairment. An estimated 36,544 tons of sediment are delivered to the stream annually. A total of 11,075 acres (38%) of the watershed are high priority areas or land with sediment delivery rates greater than one. Our goal over 15 years is to install Best Management Practices (BMPs) and increase public education in order to reduce sediment and phosphorus delivery by 25% and decrease priority areas by 15%. More specific objectives for this WIRB project are to 1) Reduce annual sediment delivery by roughly 16.3% or 1,058 tons and associated phosphorus delivery by 1,375 pounds and 2) Develop an information and education program aimed at producers and residents within the headwaters of Grant and Chester townships, which account for 18% of the watershed's priority areas. The SWCD proposes to utilize 50% EQIP funds and 25% WIRB funds toward rural BMPs, and 75% WIRB funds toward urban BMPs received through this application.

Electrical signature of modern and ancient tectonic processes in the crust of the Atlas mountains of Morocco.

The Atlas Mountains in Morocco are considered as type examples of intracontinental chains, with high topography that contrasts with moderate crustal shortening and thickening. Whereas recent geological studies and geodynamic modeling have suggested the existence of dynamic topography to explain this apparent contradiction, there is a lack of modern geophysical data at the crustal scale to corroborate this hypothesis. Newly-acquired magnetotelluric data image the electrical resistivity distribution of the crust from the Middle Atlas to the Anti-Atlas, crossing the tabular Moulouya Plain and the High Atlas. All the units show different and unique electrical signatures throughout the crust reflecting the tectonic history of development of each one. In the upper crust electrical resistivity values may be associated to sediment sequences in the Moulouya and Anti-Atlas and to crustal scale fault systems in the High Atlas developed during the Cenozoic times. In the lower crust the low resistivity anomaly found below the Mouluya plain, together with other geophysical (low velocity anomaly, lack of earthquakes and minimum Bouguer anomaly) and geochemical (Neogene-Quaternary intraplate alkaline volcanic fields) evidence, infer the existence of a small degree of partial melt at the base of the lower crust. The low resistivity anomaly found below the Anti-Atlas may be associated with a relict subduction of Precambrian oceanic sediments, or to precipitated minerals during the release of fluids from the mantle during the accretion of the Anti-Atlas to the West African Supercontinent during the Panafrican orogeny ca. 685 Ma).

Microsatellite polymorphism in the edaphic spruce, Picea asperata, originating from the mountains of China

Abstract