The use of diatom records to establish reference conditions for UK lakes subject to eutrophication

A knowledge of pre-disturbance conditions is important for setting realistic restoration targets for lakes. For European waters this is now a requirement of the European Council Water Framework Directive where ecological status must be assessed based on the degree to which present day conditions deviate from reference conditions. Here, we employ palaeolimnological techniques, principally inferences of total phosphorus from diatom assemblages (DI-TP) and classification of diatom composition data from the time slice in sediment cores dated to similar to 1850 AD, to define chemical and ecological reference conditions, respectively, for a range of UK lake types. The DI-TP results from 169 sites indicate that reference TP values for low alkalinity lakes are typically 3 m mean depth) generally had lower reference TP concentrations than the shallow sites. A small group of shallow marl lakes had concentrations of similar to 30 mu g L-1. Cluster analysis of diatom composition data from 106 lakes where the key pressure of interest was eutrophication identified three clusters, each associated with particular lake types, suggesting that the typology has ecological relevance, although poor cross matching of the diatom groups and the lake typology at type boundaries highlights the value of a site-specific approach to defining reference conditions. Finally the floristic difference between the reference and present day (surface sample) diatom assemblages of each site was estimated using the squared chord distance dissimilarity coefficient. Only 25 of the 106 lakes experienced insignificant change and the findings indicate that eutrophication has impacted all lake types with > 50% of sites exhibiting significant floristic change. The study illustrates the role of the sediment record in determining both chemical and ecological reference conditions, and assessing deviation from the latter. Whilst restoration targets may require modification in the future to account for climate induced alterations, the long temporal perspective offered by palaeolimnology ensures that such changes are assessed against a sound baseline

Riparian Functional Assessment Phase Two Summary

This report contains data regarding the drainage area, restoration strategy and banks sampled of three Waller Creek locations.In an effort to assess the response of degraded riparian buffers to the cessation of the main disturbance regime (mowing) and the facilitated succession approach to riparian restoration, the City of Austin implemented phase 2 of the Riparian Functional Assessment (RFA) which consisted of sampling degraded buffers after 1 year with no disturbance. Only degraded sites were included in this phase and their functional scores were compared with those of reference sites from the initial sample year representing healthy riparian function. A total of 9 degraded sites were added to the initial 16 degraded sites from phase 1 for this assessment. Results suggest that degraded buffers lacked the necessary time to show a response in riparian function after only one year of recovery. Sampling design changes are recommended to better assess the growing number of buffer site locations tracked in this project, including reinstituting reference site sampling and shifting to a biannual sampling regime. Based on analysis of phase 2 data, changes to the assessment tool include the following: substitute organic soil carbon for direct soil moisture measurements, coalesce the hardwood demography and recruitment parameters into woody community dynamics, and upgrade soil compaction instruments for higher accuracy and reliability.Waller Creek Working Grou

Environmental Justice: Challenges of Contaminated Site Cleanup in Rural AK

A shorter version of this article appeared on pp. 1–4 of the Summer 2018 print edition.Efforts to clean up contaminated sites from military installations and other sources have been ongoing in Alaska since the 1980s, and new sites continue to be identified. Most Formerly Used Defense Sites (FUDS) properties are in remote locations, placing a disproportionate impact on Alaska Native communities that depend upon environmental resources for their livelihood. Cleanup projects that are begun may take many years to complete due to the complicated nature of each site. Since 1990, over 5,300 sites have been cleanup up; more than 2,200 sites remain open, including military installations (both abandoned and active), bulk fuel storage and gas stations, airports and airfields, maintenance facilities, and oil exploration, transport, and refining facilities.Superfund and FUDS / Multiple projects and parties / FUDS closure but site still open / DEC closed sites vs. open sites / Assessing risk / [Sidebar:] Cleanup in rural Alaska is expensive and complicated / Liability and costs of cleanup / Financing assessment and remediation / Federal funds / Reference

Diatom assemblages in Portuguese temporary rivers

During a survey of benthic diatoms in watercourses from Portugal in spring and summer 2006 and 2007, 76 sites in temporary streams (according to the National Water Institute classification) have been studied. These streams belong to the Ribeiras do Algarve (10 sites), Guadiana (19 sites), Mira (7 sites), Sado (16 sites), Tejo (20 sites), and Douro (4 sites) watersheds. Among these 76 sites, the National Water Institute classified only 48 as reference sites, and only these were therefore considered in the statistical analysis performed. A total of 276 diatom taxa have been identified in the 48 reference sites, from which 112 were present in abundance above 2% in at least one inventory. The most frequent taxa, present in more than 50% of the studied sites, were Achnanthidium minutissimum (Kützing) Czarnecki, Amphora pediculus (Kützing) Grunow, Cocconeis euglypta Ehrenberg, Eolimna minima (Grunow) Lange-Bertalot, Gomphonema parvulum Kützing, G. rosenstockianum Lange-Bertalot & E. Reichardt, Navicula gregaria Donkin, N. veneta Kützing, Nitzschia inconspicua Grunow and Planothidium frequentissimum (Lange-Bertalot) Lange-Bertalot. These are neutrophilous to alcaliphilous, mesosaprobous to -meso-saprobous, eutraphentic to indifferent taxa. Furthermore, a multivariate analysis relating diatom assemblages with environmental parameters is presented and the ecological preferences of not yet well known taxa, such as G. rosenstockianum, are provided

Integrating nuclide specific and dose rate based methods for airborne and ground based gamma spectrometry

Results of joint airborne survey work conducted by SUERC and JAEA are presented, for areas to the north and south of Fukushima Daiichi using four different airborne survey systems, cross calibrated at reference sites in Scotland and near Namie. Airborne measurements were made at a series of different survey heights using three high volume NaI based spectrometers, and for the first time using a high resolution system based on the Ortec IDM HPGe spectrometer. The JAEA data sets were analysed using the same methods applied to national scale mapping in Japan since the accident. The SUERC data sets were analysed using nuclide specific approaches validated in the European ECCOMAGS project. The data presented on a digital terrain model show marked correspondence with landscape features, which both suggest the initial deposition processes, and indicate trajectories for future re-deposition by natural processes. All data sets are traceable to each other, and to the ground based calibration sites. Nuclide specific inventories have been defined, which can serve as a future reference to evaluate environmental change