USGS Science⌕ Search

Geology topics

A.K. Miles

Publications and source records attributed to A.K. Miles.

44 records · Page 3Linked to original sources
USGS1997

Spatial and temporal heterogeneity in metallic elements in industrialized aquatic bird habitat

This study examined the potential for exposure of migratory aquatic birds to contaminants in highly industrialized habitats at Baltimore Harbor, Maryland. Seven nearshore, benthic sites were sampled every 3 or 6 months from June 1987 to December 1988. Twenty metallic elements were measured in composites (i.e. annelids, amphipods, and isopods were pooled), clams, and sediments. Elevated concentrations were widespread throughout the sites, depending on the element. Most concentrations in composites were lowest at sites innermost and outside the harbor. Higher concentrations in composites were not related to season. Most concentrations were higher in composites than in sediments or clams, but they varied by element for clams and sediments. The largest flock of wintering waterfowl frequented the site exhibiting the highest concentrations of most elements ( p < 0.0001). Average concentrations of known toxic elements were probably not harmful to aquatic birds or their prey, but the highest detected concentrations of eight elements warrant caution. At least eight other elements exceeded background concentrations, but toxicity to birds or their prey are unknown.

Maryland↗
USGS1993

Effects of dietary aluminum, calcium, and phosphorus on egg and bone of European starlings

Egg and bone of passerine birds nesting in acidified habitats may be affected by high levels of Al or P, or low levels of Ca. Nine treatments of three levels of dietary Al (target levels of 200, 1,000, and 5,000 μg/g) and three levels of Ca:P (target levels of NN = 1.3% Ca: 0.9% P; LL = 0.19 Ca:0.45 P; LH = 0.19 Ca: 1.65 P) were fed to 16–17 starling pairs during two breeding seasons. Eggs of starlings fed the LH diet were smaller and weighed less than eggs from the NN and LL treatments. Treatment effects on thickness, strength, and weight of eggshells were not consistent between seasons, probably because of differences in actual dietary levels of Al, Ca, and P or in incubation intervals. In one season, birds fed the highest Al diet had thicker eggshells than those from the other Al treatments (no effect from Ca:P); the following season, eggshells from the NN and LH treatments were thicker and stronger than those from the LL treatment. Eggshells from the NN treatment weighed more than those from the other Ca:P treatments. Starlings on the LH diet had the strongest femurs, but the effect was interactive with different levels of dietary Al. Effects of Ca:P on egg and bone were more evident than Al effects.

Archives of Environmental Contamination and Toxico↗
USGS1993

Environmental contaminants in canvasbacks wintering on San Francisco Bay, California

The concentrations of 11 trace elements, 21 organochlorines, 13 polycyclic aromatic hydrocarbons, and 13 aliphatic hydrocarbons were determined in canvasbacks (Aythya valisineria) wintering on San Francisco Bay, California during 1988. With the exception of Se, concentrations of potentially toxic elements were low. Similarly, concentrations of most organic compounds were near or below detection limits. Aliphatic hydrocarbons, PCBs, and DDE were common, but at levels lower than those known to be harmful to waterfowl. Innocuous trace elements (Cu, Fe, and Zn), which are often associated with anthropogenic contamination, occurred at high levels. Concentrations of toxic elements were several times lower and those of benign elements were similar or greater than concentrations reported for surf scoters (Melanitta perspicillata) or greater scaup (Aythya marila) from San Francisco Bay.

California Fish and Game↗
USGS1990

Effects of experimental overgrowth on survival and change in the turf assemblage of a giant kelp forest

Crustose coralline algae were the prevalent cover among sessile organisms that paved or grew near the substratum, and also the most commonly overgrown species in a giant kelp Macrocystis pyrifera (L.) C.A. Agardh forest located off San Nicolas Island, California. Giant kelp was the largest and most conspicuous species that overgrew large patches of the substrata; overgrowth among turf organisms also appeared common. To determine the effects of giant kelp holdfasts on crustose coralline algae and other turf organisms, “artificial holdfasts” were placed on 0.125-m 2 plots for 5, 8 and 12 months. In these treatments, 50–57% of the crustose coralline algae survived. Because these algae also recruited while covered, the total cover (survivorship plus recruitment) differed by only 7–26% from that sampled at the start of the study. The decline of these algae in control plots was similar to that in the treatment plots mostly because of overgrowth by sessile invertebrates. Bryozoans increased markedly on the control plots, whereas 0–12% survived in the treatment plots. Bryozoans and sponges also recruited under the artificial holdfasts. Some arborescent turf algae survived in the 5- and 8-month treatments; articulated coralline algae survived better than did foliose algae. High survival recruitment of crustose coralline algae while overgrown contributed to their prevalence in benthic communities.

Journal of Experimental Marine Biology and Ecology↗