Book reviews

Behavioural biology of killer whales. Editors: C. Kirkevold and J. S. Lockard. Zoo Biology Monographs, Volume 1. Alan Liss Inc., New York, 1986. 457 p. ISBN 0–8451–3100–1. Price: US$79.50.

Aquaculture of Cyprinids. Editors: R. Billard and J. Marcel. Institut National de la Recherche Agronomique, 1986. 504 p. Price FF150.00. Available from INRA Publications, Route de St Cyr, 78000 Versailles, France.

The Peruvian anchoveta and its upwelling ecosystem: three decades of change. Editors: D. Pauly and I. Tsukayama. Institute) del Mar del Peru (IMARPE); Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ); International Center for Living Aquatic Resources Management (ICLARM) 1987.351 p. ISBN 971–1022–34–6, ISSN 0115–4389. Price US$17.50 surface; US$36 airmail. Available from ICLARM, MCP.O. 1501, Makati, Metro Manilla, Philippines.

The freshwater planktonic blue‐greens (Cyanophyta/Cyanobacteria) of New Zealand: a taxonomic guide. By M. K. Etheredge and R. D. Pridmore. Published for the National Water and Soil Conservation Authority, 1987. 122 p, including 93 figures. ISSN0110–4705. Price $38.50. Available from DSIR Publishing, P.O. Box 9741, Wellington, New Zealand.     

Soil erosion risk assessment of the Keiskamma catchment,South Africa using GIS and remote sensing

This paper examines the soil loss spatial patterns in the Keiskamma catchment using the GIS-based Sediment Assessment Tool for Effective Erosion Control (SATEEC) to assess the soil erosion risk of the catchment. SATEEC estimates soil loss and sediment yield within river catchments using the Revised Universal Soil Loss Equation (RUSLE) and a spatially distributed sediment delivery ratio. Vegetation cover in protected areas has a significant effect in curtailing soil loss. The effect of rainfall was noted as two pronged, higher rainfall amounts received in the escarpment promote vegetation growth and vigour in the Amatole mountain range which in turn positively provides a protective cover to shield the soil from soil loss. The negative aspect of high rainfall is that it increases the rainfall erosivity. The Keiskamma catchment is predisposed to excessive rates of soil loss due to high soil erodibility, steep slopes, poor conservation practices and low vegetation cover. This soil erosion risk assessment shows that 35% of the catchment is prone to high to extremely high soil losses higher than 25 ton ha⁻¹ year⁻¹ whilst 65% still experience very low to moderate levels of soil loss of less than 25 ton ha⁻¹ year⁻¹. Object based classification highlighted the occurrence of enriched valley infill which flourishes in sediment laden ephemeral stream channels. This occurrence increases gully erosion due to overgrazing within ephemeral stream channels. Measures to curb further degradation in the catchment should thrive to strengthen the role of local institutions in controlling conservation practice.     

Interactions of diffuse and focused allogenic recharge in an eogenetic karst aquifer (Florida, USA)

The karstic upper Floridan aquifer in north-central Florida (USA) is recharged by both diffuse and allogenic recharge. To understand how recharged water moves within the aquifer, water levels and specific conductivities were monitored and slug tests were conducted in wells installed in the aquifer surrounding the Santa Fe River Sink and Rise. Results indicate that diffuse recharge does not mix rapidly within the aquifer but instead flows horizontally. Stratification may be aided by the high matrix porosity of the eogenetic karst aquifer. Purging wells for sample collection perturbed conductivity for several days, reflecting mixing of the stratified water and rendering collection of representative samples difficult. Interpretive numerical simulations suggest that diffuse recharge impacts the intrusion of allogenic water from the conduit by increasing hydraulic head in the surrounding aquifer and thereby reducing influx to the aquifer from the conduit. In turn, the increase of head within the conduits affects flow paths of diffuse recharge by moving newly recharged water vertically as the water table rises and falls. This movement may result in a broad vertical zone of dissolution at the water table above the conduit system, with thinner and more focused water-table dissolution at greater distance from the conduit.     

Choosing methods for estimating dissolved and particulate riverine fluxes from monthly sampling

Abstract

In discrete water quality surveys, riverine fluxes are associated with unknown uncertainties (biases and imprecisions). Annual flux errors have been determined from the generation of discrete surveys by Monte Carlo sorting for monthly sampling, from 10 years of daily records (120 records). Eight calculation methods were tested for suspended particulate matter, dissolved solids and dissolved and total nutrients in medium to large basins (10³ to 10⁶ km²) covering a wide range of hydrological conditions and riverine biogeochemistry. The performance of each method was analysed first by type of riverine material, which appeared to be much less pertinent than the flux variability matrix. The latter combines the river flow duration in two percent of time (W_2%) and the truncated exponent (b_50sup) defining the relationship of concentration vs discharge (C–Q) at higher flows (C = aQ^b50sup). As flux variability increases (high W_2% and/or high b_50sup), averaging and rating curve methods become less efficient compared to hydrograph separation methods. Flux biases and imprecisions were plotted in the [W_2%, b_50sup] matrix for discrete monthly surveys.

Editor Z. W. Kundzewicz

Citation Raymond, S., Moatar, F., Meybeck, M., and Bustillo, V., 2013. Choosing methods for estimating dissolved and particulate riverine fluxes from monthly sampling. Hydrological Sciences Journal, 58 (6), 1326–1339.     

The development of an interactive multi-scale GIS

Abstract

This paper presents the development of the first geographical information system (GIS) that may be used to manipulate a single dataset at a very large range of scales (different detail levels). The design of this multi-scale GIS is fully integrated in the open DBMS Postgres and the open GIS GEO + + . Besides the system design, this paper will also give details of the implementation in the Postgres DBMS environment of three generalization tools: 1. the BLG-tree for line and area simplification, 2. the Reactive-tree for selection based on importance and location, and 3. the GAP-tree for solving problems when using the other two structures for an area partitioning. Together with the geographical frontend, the DBMS forms the flexible basis for the realization of powerful GIS applications. The implementation has been successfully benchmarked with two large datasets: World Databank II and DLMS DFAD. The response times improve by one to two orders of magnitude.     

Continuous monitoring of stream δ18O and δ2H and stormflow hydrograph separation using laser spectrometry in an agricultural catchment

A portable Wavelength Scanned‐Cavity Ring‐Down Spectrometer (Picarro L2120) fitted with a diffusion sampler (DS‐CRDS) was used for the first time to continuously measure δ¹⁸O and δ²H of stream water. The experiment took place during a storm event in a wet tropical agricultural catchment in north‐eastern Australia. At a temporal resolution of one minute, the DS‐CRDS measured 2160 δ¹⁸O and δ²H values continuously over a period of 36 h with a precision of ±0.08 and 0.5‰ for δ¹⁸O and δ²H, respectively. Four main advantages in using high temporal resolution stream δ¹⁸O and δ²H data during a storm event are highlighted from this study. First, they enabled us to separate components of the hydrograph, which was not possible using high temporal resolution electrical conductivity data that represented changes in solute transfers during the storm event rather than physical hydrological processes. The results from the hydrograph separation confirm fast groundwater contribution to the stream, with the first 5 h of increases in stream discharge comprising over 70% pre‐event water. Second, the high temporal resolution stream δ¹⁸O and δ²H data allowed us to detect a short‐lived reversal in stream isotopic values (δ¹⁸O increase by 0.4‰ over 9 min), which was observed immediately after the heavy rainfall period. Third, δ¹⁸O values were used to calculate a time lag of 20 min between the physical and chemical stream responses during the storm event. Finally, the hydrograph separation highlights the role of event waters in the runoff transfers of herbicides and nutrients from this heavily cultivated catchment to the Great Barrier Reef. Copyright © 2015 John Wiley & Sons, Ltd.     

Ostracods: The ultimate survivors

Ostracods are tiny crustacean arthropods just a few millimetres long, with a bivalved carapace made of calcium carbonate that covers the whole body, and into which the animal can retreat from the world outside. Because of their diminutive size they are largely overlooked as fossils, but they have a fascinating history. Silent witnesses to life in the seas since the time of trilobites, they have a fossil record extending back to the Early Ordovician, and possibly the Cambrian. Ostracods have survived nearly 500 million years of Earth history including the ‘big five’ mass extinctions of the Phanerozoic Eon; they are true survivors. They are almost perfectly adapted for the aquatic environments in which they live, and can be found from the ocean abyssal plains to damp leaf litter. The ostracod carapace is a triumph of biological engineering that has been re‐configured into myriad different morphologies according to environment. Streamlined and agile species plough through the ocean water column, sometimes reaching a ‘giant’ size of a centimetre in length, whilst their tinier sea bottom cousins make elaborately ornamented carapaces to withstand the pressures of living at the seabed, or shape their carapaces into forms that facilitate burrowing into sediment. Ostracods are key components of aquatic ecosystems. As primary consumers they are food for larger animals both in seabed and planktonic habitats, and they recycle much of the organic detritus produced by larger animals and plants. Delve into the history of ostracods and it is possible to find pioneers who triumphed in the plankton, early colonisers of terrestrial aquatic ecosystems, and ostracods that literally conquered the land. And in more recent times, ostracods have even hitched rides on rockets into space.     

A detailed energy budget analysis of river supercooling and the importance of accurately quantifying net radiation to predict ice formation

River supercooling and ice formation is a regular occurrence throughout the winter in northern countries. The resulting frazil ice production can obstruct the flow through intakes along the river, causing major problems for hydropower and water treatment facilities, among others. Therefore, river ice modellers attempt to calculate the river energy budget and predict when supercooling will occur in order to anticipate and mitigate the effects of potential intake blockages. Despite this, very few energy budget studies have taken place during freeze-up, and none have specifically analysed individual supercooling events. To improve our understanding of the freeze-up energy budget detailed measurements of air temperature, relative humidity, barometric pressure, wind speed and direction, short- and longwave radiation, and water temperature were made on the Dauphin River in Manitoba. During the river freeze-up period of late October to early November 2019, a total of six supercooling events were recorded. Analysis of the energy budget throughout the supercooling period revealed that the most significant heat source was net shortwave radiation, reaching up to 298 W/m², while the most significant heat loss was net longwave radiation, accounting for losses of up to 135 W/m². Longwave radiation was also the most significant heat flux overall during the individual supercooling events, accounting for up to 84% of the total heat flux irrespective of flux direction, highlighting the importance of properly quantifying this flux during energy budget calculations. Five different sensible (Q_h) and latent (Q_e) heat flux calculations were also compared, using the bulk aerodynamic method as the baseline. It was found that the Priestley and Taylor method most-closely matched the bulk aerodynamic method on a daily timescale with an average offset of 8.5 W/m² for Q_h and 10.1 W/m² for Q_e, while a Dalton-type equation provided by Webb and Zhang was the most similar on a sub-daily timescale with average offsets of 20.0 and 14.7 W/m² for Q_h and Q_e, respectively.     

<Superscript>18</Superscript>O/<Superscript>16</Superscript>O and V/Cr ratios in gem tsavorites from the Neoproterozoic Mozambique metamorphic belt: a clue towards their origins?

The combination of oxygen isotope composition with V–Cr–Mn trace element concentrations of V-bearing garnets (tsavorites) originating from the main deposits of the Neoproterozoic Mozambique Metamorphic Belt is reported for the first time. The database enables the identification of the geological and geographical sources of the main productive areas from northern and southern Tanzania, Kenya, and Madagascar. Three consistent sets of δ¹⁸O values between 9.5‰ and 11.0‰, 11.6‰ and 14.5‰, and 15.5‰ and 21.1‰ have been recognized for primary deposits hosted in graphitic gneisses related to the Neoproterozic metasedimentary series. The δ¹⁸O value of tsavorite is a good tracer of the environment of its formation; the δ¹⁸O of the fluid in equilibrium with tsavorite was buffered by the host rock during metamorphism and fluid-rock interaction. This study is a first step in characterizing the geochemistry of gem tsavorite from most of the deposits and occurrences worldwide.     

Effects of short-term ecosystem experimental warming on water-extractable organic matter in an ombrotrophic Sphagnum peatland (Le Forbonnet, France)

In a future warmer world, peatlands may change from a carbon sink function to a carbon source function. This study tracks changes in water-extractable organic matter (WEOM) after 1 year of in situ experimental warming using open top chambers (OTCs). WEOM was studied in the upper peat layers (0–10 cm) through analysis of water-extractable organic carbon (WEOC), stable C isotopic composition (δ¹³C), specific UV absorbance at 280 nm and sugar composition of cores taken from an open bog (DRY sites) and a transitional poor fen (WET sites). At the DRY sites, the impact of OTCs was weak with respect to WEOM parameters, whereas at the WET sites, the air warming treatment led to a decrease in peat water content, suggesting that the supply of heat by OTCs was used mainly for evapotranspiration. OTCs at the WET sites also induced a relative enrichment at the surface (0–5 cm depth) of aliphatic and/or aromatic compounds with concomitant decrease in WEOC, as a result of decomposition. On the contrary, WEOC and sugar content increased in the deeper peat layer (7.5–10 cm depth) probably as a result of increased leaching of phenolic compounds by roots, which then inhibits microbial activity. The different response to experimental warming at DRY and WET sites suggests that the spatial variability of moisture is critical for understanding of the impact of global warming on the fate of OM and the carbon cycle in peatlands.