To roam or to home: site fidelity in a tropical coastal shark

Understanding patterns in site fidelity is important for defining the ecological role of species in the systems they use and for gauging the effects of human impacts on their populations. We analyzed long-term movement data of adult spottail sharks (Carcharhinus sorrah) in Cleveland Bay, Australia, to define the degree of site fidelity this species shows to coastal areas. Individuals were monitored in the study site for 28–566 days, and residency index (i.e., proportion of days present to total monitoring period) ranged from 0.08 to 0.95. Using a randomization procedure, we determined that the movement paths for 90 % of individuals (11 female and 7 male) were more constrained than random, with individuals exhibiting a high degree of site fidelity to consistent areas within the study site. Examining distances moved revealed that individuals used the same areas repeatedly and remained in close proximity (i.e., <6 km) to their location of first detection. While some individuals consistently used and returned back to the same locations, low residency among others suggests that a portion of the population may roam more widely. Long-term site fidelity to consistent areas may be a successful behavioral strategy for C. sorrah by increasing individual fitness through spatial familiarity and knowledge of resources.     

Magneto-biomonitoring of intra-urban spatial variations of particulate matter using tree leaves

Preliminary mineral magnetic results from a pilot project investigating the suitability of roadside tree leaves as depositories of vehicular pollution are presented. Tree leaf surfaces (Lime: Tilia europaea; Sycamore: Acer pseudoplatanus) at four roadside and one woodland location in Wolverhampton, UK, have been monitored (July 2003 to November 2003). Mineral magnetic technologies have revealed spatial variations of particulate pollution concentration throughout the conurbation and data analysis indicates that magnetic concentration parameters are suitable proxies for fine particulate pollution, which are particularly hazardous to health. Site-specific traffic management and associated vehicle behaviour appear to be chiefly responsible for the magnetic concentration differences between sites. Magneto-biomonitoring in this way allows the high-resolution spatial mapping of particulate matter (PM) pollution, which may also benefit epidemiology in better assessing exposure to vehicular-derived particulates. Given the speed, measurement sensitivity and non-destructive nature of the technique, it is proposed that this low-cost approach offers some advantages over centralised monitoring stations to monitor urban roadside particulate pollution.     

Growth rate of the bathypelagic crustacean Gnathophausia ingens (Mysidacea: Lophogastridae)

The content of water, ash, carbohydrate, lipid, protein, chitin, carbon, hydrogen, nitrogen and energy was measured for all life stages of the bathypelagic mysid Gnathophausia ingens collected in San Clemente Basin off Southern California, USA between January 1969 and February 1982. These data are used to examine the life history, growth rates, growth pattern and partitioning of material and energy over the life of this species. Females reproduce only once and brood their young for about 1.5 yr, during which time the females do not feed. This species has a very high reproductive effort: of the energy accumulated over its life, 61.3% is used in egg production, 13.4% in parental care of young, 5.6% in cast exoskeletons and only 19.6% remains in the females after brooding. The relative rate of growth (percentage of energy d^?1) is about 1% immediately after leaving the mother and declines to about 0.2% as maturity is approached. Such growth rates appear to be typical for an animal of this size living at low temperatures. The evolutionary context of this mysid's life history is discussed.     

Evaluation of chlorophyll fluorescence, in vivo spectrophotometric pigment absorption and ion leakage as biomarkers of UV-B exposure in marine macroalgae

The photosynthetic fluorescence ratio F_v:F_m, in vivo absorption spectra and ion leakage were evaluated as biomarkers of ambient and elevated UV-B (280 to 320 nm) exposure of the intertidal alga Enteromorpha intestinalis (Chlorophyta) and the sublittoral alga Palmaria palmata (Rhodophyta). Measurements of thallus growth were also used to assess adverse biological effects. Ambient and elevated UV-B significantly inhibited photosynthesis in both species. It was shown that the F_v:F_m ratio is a sensitive, non-specific general biomarker of UV-B exposure in both species. Moreover, the in vivo absorption of what was tentatively identified as chlorophylls a and b as well as phycoerythrin and/or carotenoids, phycoerythrobilin and phycocyanin decreased in a dose-response dependent manner and was associated with a decrease in growth rate in P. palmata. The intertidal alga E. intestinalis showed a greater degree of tolerance to UV-B exposure. These results indicate that changes in the F_v:F_m ratio together with reductions in in vivo pigment absorption could provide an early quantitative warning of the detrimental effects of UV-B in marine macroalgae. Received: 16 May 1997 / Accepted: 16 July 1997     

Palatability mapping: a koala's eye view of spatial variation in habitat quality

Ecologists trying to understand the value of habitat to animals must first describe the value of resources contained in the habitat to animals and, second, they must describe spatial variation in resource quality at a resolution relevant to individual animal foraging. We addressed these issues in a study of koalas (Phascolarctos cinereus) in a Eucalyptus woodland. We measured beneficial and deterrent chemical characteristics as well as the palatability of trees using a near-infrared spectroscopic model based on direct feeding experiments. Tree use by koalas was influenced by tree size and foliar quality but was also context-dependent: trees were more likely to be visited if they were surrounded by small, unpalatable trees or by large, palatable trees. Spatial autocorrelation analysis and several mapping approaches demonstrated that foliar quality is spatially structured in the woodland at a scale relevant to foraging decisions by koalas and that the spatial structure is an important component of habitat quality.     

The contribution from shipping emissions to air quality and acid deposition in Europe

A global three-dimensional Lagrangian chemistry-transport model STOCHEM is used to describe the European regional acid deposition and ozone air quality impacts along the Atlantic Ocean seaboard of Europe, from the SO2, NOx, VOCs and CO emissions from international shipping under conditions appropriate to the year 2000. Model-derived total sulfur deposition from international shipping reaches over 200 mg S m(-2) yr(-1) over the southwestern approaches to the British Isles and Brittany. The contribution from international shipping to surface ozone concentrations during the summertime, peaks at about 6 ppb over Ireland, Brittany and Portugal. Shipping emissions act as an external influence on acid deposition and ozone air quality within Europe and may require control actions in the future if strict deposition and air quality targets are to be met.     

Air emission flux from contaminated dredged materials stored in a pilot-scale confined disposal facility

A pilot-scale field simulation was conducted to estimate the air emissions from contaminated dredged material stored in a confined disposal facility (CDF). Contaminated dredged material with a variety of organic chemicals, obtained from Indiana Harbor Canal, was used in the study. It was placed in an outdoor CDF simulator (i.e., a lysimeter of dimensions 4 ft x 4 ft x 2 ft). A portable, dynamic flux chamber was used to periodically measure emissions of various polynuclear aromatic hydrocarbons (PAHs). A weather station was set up to monitor and record the meteorological conditions during the experiment. The fluxes of several PAHs were monitored over time for 6 1/2 months. Initial 6-hr average fluxes varied from 2 to 20 ng/cm2/hr for six different PAHs. The flux values declined rapidly for all compounds soon after placement of the dredged material in the CDE Chemical concentrations derived from flux values were generally of low magnitude compared with ambient standards. Data obtained from the experiment were compared against those predicted using models for air emissions. Model simulations showed that initially the flux was largely from exposed pore water from saturated (wet) sediment, whereas the long-term flux was controlled by diffusion through the pore air of the unsaturated sediment. Model predictions generally overestimated the measured emissions. A rainfall event was simulated, and the dredged material was reworked to simulate that typical of a CDF operation. Increased flux was observed upon reworking the dredged material.