Theoretical link between rainfall and flood magnitude

The rainfall–run‐off convolution integral is analytically solved for several models for the elementary hydrograph. These solutions can be combined with available rainfall frequency analyses to predict flood flows along streams for different recurrence intervals, using no free parameters for gauged streams and one estimable parameter for ungauged streams. Extreme discharge magnitudes at gauged sites can be typically estimated within a factor of two of actual records, using no historical data on extreme flows. The flow predictions reproduce several important characteristics of the flood phenomenon, such as the slope of the regression line between observed extreme flows and basin area on the conventional logQ versus logA plot. Importantly, for the models and data sets investigated, the storm duration of greatest significance to flooding was found to approximate the intrinsic transport timescale of the particular watershed, which increases with basin size. Thus, storms that deliver extraordinary amounts of rainfall over a particular time interval will most greatly activate basins whose time constants approximately equal that interval. This theoretical finding is supported by examination of the regional hydrological response to the massive storms of September 14, 2008, and April 28–30, 2017, which caused extraordinary record flooding of basins of about 5–100 km² and 500–4,000 km², respectively, but produced few records in basins that were larger or smaller than those ranges.     

Diatom and foraminifera relationships to water quality in The Coorong,South Australia,and the development of a diatom-based salinity transfer function

The Ramsar-listed Coorong lagoon lies at the terminus of the Murray-Darling River system in South Australia. Diatom and foraminifera relationships with water quality were characterised in order to develop diatom- and foraminifera-based models with the potential to infer water column salinity. Seventy-four samples were collected during 2007, a year of continuing drought in the catchment, and of no discharges at the Murray Mouth. The sample sites had a salinity gradient of 1.8–190 g l⁻¹ total dissolved solids. The diatom data set comprised 215 taxa, while there were only eight taxa in the foraminiferal data set. Canonical correspondence analysis of diatom species-environment relationships showed that salinity explained the largest proportion of diatom variance. Hence, a diatom-based salinity transfer function with reasonable predictive power (measured vs. diatom-inferred salinity r _jack² = 0.82; Root Mean Squared Error of Prediction = 16 g l⁻¹) was developed. Application of the transfer function to fossil diatom assemblages from The Coorong suggested that pre-European salinity values were generally >50 g l⁻¹ and that salinity declined following settlement. These results, however, contradict the recent history of The Coorong where there have been substantial lagoon-wide salinity increases. The pre-impact diatom flora has no analogue in the modern data set, highlighting the degree of departure from past conditions. CCA of the foraminiferal data set identified salinity and total nitrogen as the variables with the greatest explanatory power. However, accurate predictive models could not be developed using either variable due to low foraminiferal abundance and species richness. These factors may have been a consequence of diminished foraminiferal recruitment rates over successive years, an artefact of reduced marine water input to The Coorong. Future attempts to generate predictive models from this region would benefit from the inclusion of data from distant locations, since suitable analogue sites do not exist in close proximity. The study has generated useful insights to the apparently broad salinity tolerances for several cosmopolitan diatom and foraminifera species, and has identified a number of diatom and foraminifera taxa that may prove useful in the qualitative interpretation of down-core trends in The Coorong and the lower Murray River region.     

The U.P. Mammoth Site,Carbon County,Wyoming, USA: More Questions than Answers

In the summer of 1960, mammoth bones were discovered by a dragline operator in southern Wyoming at the Union Pacific (U.P.) Mammoth site. Although subsequent archaeological work during 1960 and 1961 identified artifacts in association with the mammoth remains, many authors have since questioned the nature of that association. Also, little has been published about the site other than a brief article in National Geographic Magazine in 1962. In this paper, we present additional information on the U.P. Mammoth site including stratigraphic profiles from the first author's geoarchaeological work in 1961, stratigraphic and spatial location of bones and artifacts derived from the original field notes, and new radiocarbon dates. Although the precise stratigraphic provenance for many artifacts and skeletal elements remains unclear, a compelling argument can be made for spatial and stratigraphic association of the mammoth remains with the artifact assemblage suggesting some kind of human interaction with the animal.     

Annual and spatial variation in the abundance length and condition of juvenile turbot (Psetta maxima L.) on nursery grounds on the west coast of Ireland: 2000–2007

Turbot (Psetta maxima Linnaeus) is a high value commercially exploited marine flatfish which occurs in European waters, from the Northeast Atlantic to the Arctic Circle, the Baltic and Mediterranean Sea. In Ireland, turbot are the most valuable commercial non-quota species. Very little is known about their population dynamics in the wild, in particular during the sandy beach nursery phase of the life history. In 2000, a survey was established to assess flatfish species on nursery grounds on the west coast of Ireland. Eleven sandy beaches were assessed for 0+ turbot by beach seining, over an eight year period (2000–2007) during the months of August and September. The objective of the study was to estimate juvenile turbot abundance and size structure to determine if any spatial and annual trends existed. Large scale variability in the recruitment of fish to nursery grounds may be indicative of fluctuations in the adult stock. Turbot were found to recruit to five beaches consistently over the eight year period. Temporal and spatial variability in the relative abundance and length of turbot was discerned, with no apparent overall trend. However, certain nursery grounds were shown in most of the years examined to support higher abundances of turbot in comparison to other areas over the eight year period. Turbot abundances on nursery grounds were significantly correlated with mean spring sea temperatures during the pelagic stage. The condition of turbot did not significantly differ on an annual or spatial scale. Mean densities of 0+ turbot along the Irish coast were found to be similar and at times higher than other areas in Europe, ranging from 0.1 (± 0.3) individuals 1000 m^− 2 to 18.5 (± 6.9) individuals 1000 m^− 2. Mean turbot total length on beaches ranged from 3.8 cm (± 0.6) to 6.6 cm (± 4.3). The observed spatial and temporal variability in abundance and length highlights the need for long-term studies when assessing juvenile flatfish populations. Results from the present study have provided much needed baseline data on wild juvenile turbot populations which is severely lacking for this species both on an Irish and on a European scale.     

The morphological development of alpine valley heads in the Antarctic Peninsula

Glaciation has continued in Antarctica for longer than anywhere else on Earth, so the long-term development of glaciated landforms can be investigated. Complex alpine valley heads up to 36 km wide are found in the Antarctic Peninsula. The largest of these may represent an advanced stage of alpine glaciation, having evolved from the earliest corries which could have developed around the early Oligocene. This study is based on a morphometric analysis of the plan form of 1680 alpine valley heads. This is a much larger sample than used by any previous study. Skewed distributions of dimensional properties (width, length and area) suggest that small corries are continually being added to the population, as older ones are enlarged and some eliminated by coalescence and ice sheet erosion. Very large features are found only in parts of Graham Land and Alexander Island, where lack of high-level ice sheet erosion has allowed the forms of mountain glaciation to dominate the landscape. The attainment of an equilibrium planform shape is suggested by the persistence of an equidimensional form, the development of characteristic or limiting values of other morphometric properties, e.g. planform closure and basin order, and by the intercorrelation of morphometric properties. A combination of branching and coalescence is fundamental in the development of corries. The latter results both in widening, which counteracts the tendency towards lengthening observed by other workers, and also in a limit to basin complexity. © 1998 John Wiley & Sons, Ltd.     

An Acheulian site near Bir Kiseiba in the Darb el Arba'in Desert,Egypt

A small concentration of Acheulian cleavers and handaxes within the driest region on Earth adds to the increasing evidence that the eastern Sahara was considerably more verdant during the Middle Pleistocene than it is today. The similarities to stone artifact assemblages of Acheulian sites in sub-Saharan Africa and in the Levant support the evidence for the movement of hominids, utilizing the Kombewa lithic technology, between Africa and the Middle East during the Middle Pleistocene. © 1997 John Wiley & Sons, Inc.     

Pesticide and Herbicide Residues in Sediments and Seagrasses from the Great Barrier Reef World Heritage Area and Queensland Coast

Pesticides and herbicides including organochlorine compounds have had extensive current and past application by Queensland's intensive coastal agriculture industry as well as for a wide range of domestic, public health and agricultural purposes in urban areas. The persistent nature of these types of compounds together with possible continued illegal use of banned organochlorine compounds raises the potential for continued long-term chronic exposure to plants and animals of the Great Barrier Reef. Sediment and seagrass samples were collected from 16 intertidal and 25 subtidal sampling sites between Torres Strait and Townsville, near Mackay and Gladstone, and in Hervey and Moreton Bays in 1997 and 1998 and analysed for pesticide and herbicide residues. Low levels of atrazine (0.1–0.3 μg kg⁻¹), diuron (0.2–10.1 μg kg⁻¹), lindane (0.08–0.19 μg kg⁻¹), dieldrin (0.05–0.37 μg kg⁻¹), DDT (0.05–0.26 μg kg⁻¹), and DDE (0.05–0.26 μg kg⁻¹) were detected in sediments and/or seagrasses. Contaminants were mainly detected in samples collected along the high rainfall, tropical coast between Townsville and Port Douglas and in Moreton Bay. Of the contaminants detected, the herbicide diuron is of most concern as the concentrations detected have some potential to impact local seagrass communities.