Assessment of trace metals contamination in soil,leaf litter and leaf beetles (Coleoptera,Chrysomelidae) in the vicinity of a metallurgical factory near Menzel Bourguiba (Tunisia)

Metal pollution is a major environmental danger owing to the rapid increase of urbanization and anthropogenic activities, which may damage the fauna and flora. Insects are often used as bioindicators of the accumulation of toxic elements. We measured concentrations of Cu, Fe, Mn, Zn, Al, and Pb in soil, litter and leaf beetles: Oulema gallaeciana (Heyden, 1879) and Lachnaia paradoxa (Olivier, 1808) at four sampling sites at different distances from metallurgical factory near Menzel Bourguiba (Tunisia). Metal concentrations did not extend beyond a distance of 4 km and were restricted to the immediate surroundings. Significant difference between sites was found for Cu, Fe, Al, and Mn concentrations in leaf litter and only for Pb in soil. In the case of Lachnaia paradoxa, no significant differences were found in the contaminant, except for Cu. The concentrations of Fe and Cu were high in Oulema gallaeciana. Positive correlations were detected for metals in the soil, leaf beetles and leaf litter. Our study confirms that the contaminants can transfer from plants to species.     

Irrigated agriculture and freshwater wetlands: A struggle for coexistence in the western United States

This paper is a review of the major environmental problems associated with irrigated agriculture in the western United States. Freshwater wetlands are being contaminated by subsurface agricultural irrigation drainage in many locations. Historic freshwater inflows have been diverted for agricultural use, and remaining freshwater supplies are not sufficient to maintain these important natural areas once they are degraded by irrigation drainage. Migratory birds have been poisoned by drainwater contaminants on at least six national wildlife refuges; waterfowl populations are threatened in the Pacific and Central flyways. Revised water allocation policies and regulatory actions are probably necessary to correct existing damage and prevent future problems. The benefits of maintaining healthy wetlands should be used as a rationale for negotiating increases in freshwater supplies. Cost analyses that show the importance of wetlands in dollar values are critical to the success of these negotiations. The next few years will provide unique opportunities for wetland managers to use cost analyses to make changes in water allocation policies. Federally subsidized water has supported and expanded agriculture at the expense of native wetlands for over 100 years in the western United States. This trend must be reversed if these wetlands and their fish and wildlife populations are to survive.     

Elevated standard metabolic rate in a freshwater shrimp (Palaemonetes paludosus) exposed to trace element-rich coal combustion waste

I conducted a transplant experiment to determine whether standard metabolic rate (SMR) of a freshwater shrimp (Palaemonetes paludosus) would be affected by exposure to trace element-enriched coal combustion waste (‘coal ash'). Shrimp were transplanted into replicate cages in a coal ash-polluted site and a reference site for 8 months. The coal ash-polluted site was characterized by elevated sediment concentrations of As, Cd, Cr, Cu, Ni, Pb, and Se compared to sediments in the reference site. After 8 months in the study sites, shrimp in the polluted site appeared to have accumulated As, Cd, and Se from the habitat, but there were no differences in survival between the study sites. However, mean SMR of shrimp (measured as O₂ consumption at rest) held in the polluted site was 51% higher than mean SMR of shrimp held in the reference site. The elevation in SMR indicates that the energetic costs of maintenance are greater for shrimp chronically exposed to the coal-ash polluted environment than shrimp in the reference site. It is likely, therefore, that other physiological or behavioral processes may be modified in the pollution-exposed individuals to compensate for the increased energy demands for maintenance. Recent studies have reported similar elevations in SMR in an amphibian and a reptile chronically exposed to coal ash. Analogous physiological responses in such taxonomically diverse animals (a crustacean, an amphibian, and a reptile) indicate that elevated SMR may be a general response by many types of organisms exposed to the mixture of trace elements characteristic of coal ash. The relationships among pollution-induced elevations in maintenance expenditures, long-term health of individuals, and population-level parameters require further attention.     

Book review

Professional amateurs and amateur professionals     

Problems of an aquatic diet in trace element analysis: The coastal site of Qurum RH5 (Sultanate of Oman, 3.700–3.200 b.C.)

Trace elements analysis, as an indicator of ancient diets, has been carried out to the human skeletal remains from the necropolis of RH5 and RH10 of Qurum (Sultanate of Oman, 3700–3200 B.C.). Soil samples from the inner part of the burials, shells, fish, turtles and herbivorous remains have been analyzed. Regarding the human bones, a first set (ribs) was related to 26 females and 41 males while a second set (femurs) was related to 22 females and 34 males. Four trace elements, among the most common indicators of diet, have been taken into consideration (barium, strontium, zinc and copper) for their stability to diagenetic effects. Manganese has been analyzed to determine the incidence of diagenesis. Data from the two sets of human bones show a narrower range of values for the femurs than for the the ribs, in agreement with a lower incidence of diagenesis in compact bones. A wider range of values from the animal samples show a higher incidence of diagenetic effects in these remains. Low levels of variability can be stressed for the soil samples. Post-mortem exchange could have more likely occurred in the outer parts of spongy bones, as manganese seems to show. The wide range of values from the ribs and, on the contrary, the narrow range from the femur indicate that an accurate choice of sample can reduce the effects of diagenesis. Regarding the alimentary habits of the groups from Qurum, the human samples (both males and females) show high rates of strontium, similar to the herbivorous. This could be associated to an aquatic diet. It is unlikely that the high levels of strontium could be linked to a high incidence of vegetables in the diet. Also archeological data seem to stress a prevalence of aquatic food in the diet. Not always do statistical analyses applied to groups with different anthropological or chronological characteristics give clear answers to the identification of ranges of values, but they have always been a valid support for the interpretation of data.     

Small pits associated with renilla (Cnidaria: Pennatulacea) on a modern low‐energy sandflat,Kiawah Island,South Carolina,U.S.A.

Small, shallow circular pits containing the Atlantic sea pansy, Renilla reniformis, were fairly common at one locality on the lower foreshore of Kiawah Island in June, 1997. Many of the pits were positioned on the stoss side of sand ripples; the organisms were oriented with their bilateral plane of symmetry essentially parallel to ripple crests. If preserved as concave epireliefs or convex hyporeliefs on bedding surfaces, such pits would be difficult not only to attribute to a trace producer or traditional ethologic category, but to identify as trace fossils in the first place.     

The trace fossil Cruziana semiplicata and the trilobite that made it

A set of criteria is suggested for associating a trace fossil with a plausible fossil: (1) close association in the field; (2) concurrent stratigraphic range; (3) a minimal choice of candidates available that could have made the trace; (4) consistent size range between trace fossil population and that of the maker; and (5) consistent biogeographic ranges for both. In the Upper Cambrian Andam Formation of Oman, there is a rare, direct association between trilobite body fossils and the trace fossil Cruziana in the same rock succession. An association of the trilobite Maladioidella cf. colcheni with the trace fossil Cruziana semiplicata is supported by the criteria listed. Maladioidella is associated with C. semiplicata over a wide geographical area in western Gondwana. It is therefore likely that some Cruziana species were made by trilobites.     

Fossil footprints and what they mean for hominin paleobiology

Hominin footprints have not traditionally played prominent roles in paleoanthropological studies, aside from the famous 3.66 Ma footprints discovered at Laetoli, Tanzania in the late 1970s. This contrasts with the importance of trace fossils (ichnology) in the broader field of paleontology. Lack of attention to hominin footprints can probably be explained by perceptions that these are exceptionally rare and “curiosities” rather than sources of data that yield insights on par with skeletal fossils or artifacts. In recent years, however, discoveries of hominin footprints have surged in frequency, shining important new light on anatomy, locomotion, behaviors, and environments from a wide variety of times and places. Here, we discuss why these data are often overlooked and consider whether they are as “rare” as previously assumed. We review new ways footprint data are being used to address questions about hominin paleobiology, and we outline key opportunities for future research in hominin ichnology.