Groundwater management by watershed agencies: an evaluation of the capacity of Ontario's conservation authorities

Watershed-based resource management organizations around the world are becoming more involved in groundwater management. This reflects, among other considerations, growing awareness of the critical role that these local agencies can and should play in the management of groundwater resources. Ontario's conservation authorities (CAs) are an important example. CAs are taking on new responsibilities for groundwater data collection, monitoring and planning. Unfortunately, not all local organizations are equally capable of participating effectively in groundwater management. This certainly is the case among Ontario's 38 CAs, which have highly variable levels of financial and staff resources. Local capacity for water management can be explored from the perspective of the institutional environment, the watershed community, and the financial, technical and staff resources of the organizations. This paper presents an evaluation of the groundwater management capacity of Ontario's conservation authorities, drawing on two detailed case studies (the Upper Thames River CA and the Ganaraska Region CA), and additional data gathered from all 38 CAs. Institutional issues, such as the clarity of management roles and senior government commitment to local management, as well as resourcing concerns, local working relationships, and public support, largely determine the capacity of CAs to expand their involvement in groundwater management. Strengthening the capacity of watershed-based agencies to participate in groundwater management is an important challenge in all jurisdictions, as these agencies are well placed to reinforce municipal groundwater management by identifying local needs and trends, facilitating communication and cooperation, and promoting best management practices.     

The biodegradation of lactic acid-based poly(ester-urethanes)

The biodegradability of lactic acid based poly(ester-urethanes) was studied using the headspace test method, which was performed at several elevated temperatures. The poly(ester-urethanes) were prepared using a straight two-step lactic acid polymerization process. The lactic acid is first condensation polymerized to a low molecular weight hydroxyl-terminated telechelic prepolymer and then the molecular weight is increased with a chain extender such as diisocyanate. In the biodegradation studies the effect of different stereostructures (different amounts of D-units in the polymer chain), the length of ester units, and the effect of crosslinking on the biodegradation rate were studied. The results indicate that poly(ester-urethanes) do not biodegrade at 25‡C, but at elevated temperatures they biodegrade well. The different stereostructures and crosslinking have a strong influence on the biodegradation rate. The length of ester units in the polymer chain also affects the biodegradation rate, but much less than crosslinking and stereostructure.     

A new method to assess the deformations of internal organs of the abdomen during impact

Objectives: Due to limitations of classic imaging approaches, the internal response of abdominal organs is difficult to observe during an impact. Within the context of impact biomechanics for the protection of the occupant of transports, this could be an issue for human model validation and injury prediction.

Methods: In the current study, a previously developed technique (ultrafast ultrasound imaging) was used as the basis to develop a protocol to observe the internal response of abdominal organs in situ at high imaging rates. The protocol was applied to 3 postmortem human surrogates to observe the liver and the colon during impacts delivered to the abdomen.

Results: The results show the sensitivity of the liver motion to the impact location. Compression of the colon was also quantified and compared to the abdominal compression.

Conclusions: These results illustrate the feasibility of the approach. Further tests and comparisons with simulations are under preparation.     

The effects of antifoulant-paint-contaminated sediments on coral recruits and branchlets

The 184-m cargo ship "Bunga Teratai Satu" ran aground on Sudbury Reef, within the Great Barrier Reef Marine Park, on 2 November 2000. Although no cargo or fuel was lost, the ship remained aground for 12 days and a large quantity of antifoulant paint containing tributyltin (TBT), zinc, and copper was scraped from the hull during the grounding and subsequent refloating operation. This resulted in extensive contamination of the reef sediments for up to 250 m surrounding the grounding site. Two laboratory-based experiments assessed the impact of contaminated sediments on the survival of both newly settled corals of Acropora microphthalma and branchlets of A. formosa. Newly settled corals exposed to sediments containing 8.0 mg kg^–1 TBT, 72 mg kg^–1 Cu, and 92 mg kg^–1 Zn or greater suffered significantly higher mortality after 72 h, compared to control or low-concentration treatments. Coral recruits exposed to 40 mg kg^–1 TBT (Sn), 306 mg kg^–1 Cu, and 403 mg kg^–1 Zn were all killed within 38 h. Branchlets from adult corals exposed to sediments with a high concentration of contaminants (TBT 160 mg kg^–1, Cu 1,180 mg kg^–1, and Zn 1,570 mg kg^–1) suffered significant mortality (38%), whereas branchlets placed in treatments with lower levels of contaminants suffered no mortality. Visual bleaching of the branchlets was observed at high contaminant levels, but an overall reduction in the symbiotic zooxanthellae populations was not observed in surviving corals. The photosynthetic yields of light-adapted zooxanthellae remained constant in live branchlets, indicating that the TBT-contaminated sediment may be more toxic to the host than the symbiont. Our results show that antifoulant contamination at ship-grounding sites has the potential to cause major mortality of resident coral communities and can have a negative impact on the recovery of adult populations.Communicated by P.W. Sammarco, Chauvin     

Phylogeography of Cerastoderma glaucum (Bivalvia: Cardiidae) across Europe: a major break in the Eastern Mediterranean

Molecular variation of the lagoon cockle Cerastoderma glaucum (Poiret, 1789) was examined across the species range along European coasts, from the northern Baltic to the Black Sea and the Caspian Sea. A major phylogeographic break in mitochondrial COI gene sequences (divergence 6.2%) separated a group of Ponto-Caspian and Aegean Sea haplotypes from those to the west of the Peloponnese peninsula in the Mediterranean and in the Atlantic-Baltic sector. A similar subdivision, yet not entirely geographically coincident, was found at 16 allozyme loci (Nei's distance D=0.15). The results imply a long-term isolation of populations in parts of the Eastern Mediterranean or Black Sea basins through the Pleistocene. The subdivision does not concur with previous views on the systematics of C. glaucum complex, but the pattern is notably similar to that described earlier from some fish species. Marked phylogeographic structuring was also found at lower level within the major Mediterranean-Atlantic phylogroup of C. glaucum, which was divided into six regional or local haplotype subgroups. Divergence of these groups may date back one or several major Pleistocene climatic cycles. Local mtDNA diversity was particularly high in a sample from the Ionian Sea, whose mitochondrial identity was of the Mediterranean-Atlantic type, while its nuclear characters were more strongly associated with the Ponto-Caspian type. Patterns of shallower, star-phylogeny type diversity within the Ponto-Caspian phylogroup and in the Baltic Sea area may represent more recent, post-glacial generation of variation.     

Production of sexuals in a fission-performing ant: dual effects of queen pheromones and colony size

Models based on the kin selection theory predict that in social hymenopterans, queens may favor a lower investment in the production of sexuals than workers. However, in perennial colonies, this conflict may be tuned down by colony-level selection because of the trade off between colony survival and reproductive allocation. In this study, we present a survey of sexual production in colonies of Aphaenogaster senilis, a common species of ant in the Iberian Peninsula. Similar to most species that reproduce by fission, males were found in large excess compared to gynes (172:1). Sexuals were more likely to be found in queenless than in queenright (QR) field colonies. However, we also found a few gynes and numerous males in very large QR colonies. We compared these data with those available in the literature for A. rudis, a congeneric species from North America that has independent colony founding. The sex ratio in this species was only five males for each female, and sexuals were mostly found in QR nests, irrespective of colony size. We confirmed queen inhibition of sexual production in A. senilis in laboratory experiments and provide evidence that this inhibition is mediated by a nonvolatile pheromone. To seek the potential source of such a queen pheromone, we analyzed the secretions of two conspicuous exocrine glands, the Dufour’s and postpharyngeal glands (DG and PPG, respectively) in both queens and workers. Both secretions were composed of hydrocarbons, but that of DG also contained small quantities of tetradecanal and hexadecanal. The hydrocarbon profile of the DG and PPG showed notable caste specificity suggesting a role in caste-related behavior. The PPG secretions also differed between colonies suggesting its role in colony-level recognition. We suggest that in A. senilis, there are two modes of colony fission: First, in very large colonies, gynes are produced, probably because of the dilution of the queen pheromone, and consequently one or more gynes leave the mother colony with workers and brood to found a new nest. This is beneficial at the colony level because it avoids the production of costly sexuals in small colonies. However, because the queen and workers have different optima for sexual production, we hypothesize that queens tend to overproduce the pheromone to delay their production. This in turn may drive workers to leave the mother colony during nest relocation and to produce sexuals once they are away from the queen’s influence, creating a second mode of colony fission.     

New insights into temperature-induced white muscle growth plasticity during Dicentrarchus labrax early life: a developmental and allometric study

Dicentrarchus labrax is a major finfish of interest in Mediterranean aquaculture. As the development of its hatchery production had gone with an increase of its larval rearing temperature, we studied the effect of a constant high (20°C) and two lower (13 and 15°C) temperatures on its early white muscle growth, with developmental and allometric approaches. D. labrax, sampled at hatching and at three developmental stages corresponding to main events in fish early life (first exogenous feeding, notochord flexion and completion of fin ray counts), were histologically processed in order to follow changes in the white myotomal muscle size, cellularity and localisation of proliferative nuclei. Morphometric analyses showed that, for 13, 15 and 20°C incubated/reared D. labrax, the total cross-sectional area of white muscle increased slowly in eleutheroembryos shorter than 5.2 mm, and four times faster in longer fish (free-swimming larvae). White muscle growth occurred both by hypertrophy (increase in muscle fibre size) and hyperplasia (increase in total number of muscle fibres) in all sampled fish, but both processes were higher in free-swimming larvae than in eleutheroembryos. The morphometric establishment of a higher hyperplastic growth of white muscle in free-swimming larvae was confirmed at immunological level by a high occurrence of proliferative nuclei. Early thermal environment was demonstrated to affect the growth process of white muscle on a different way in eleutheroembryos and free-swimming larvae: in the former, white muscle hypertrophy was stimulated at 20°C and hyperplasia at lower temperature, whereas in the latter, both white muscle hypertrophy and hyperplasia were more stimulated at 20°C than at lower temperatures. This was verified at once when the fish length and the white muscle total cross-sectional area were used as explicative variables.     

Experimental support for the cost–benefit model of lizard thermoregulation

According to Huey and Slatkin’s [Q Rev Biol 51:363–384, 1976] cost–benefit model of behavioural thermoregulation, lizards should adjust their thermoregulatory strategy between active thermoregulation and thermoconformity (no thermoregulation) according to the costs (time and energy spent thermoregulating, exposure to predators), benefits (optimised physiological performance) and thermal quality of environment associated with a given situation. However, Gilchrist’s [Am Nat 146:252–270, 1995] model of thermal specialisation suggests that apparently costly mechanisms of behavioural thermoregulation can greatly increase fitness if the optimal body temperature is achieved. Field studies of ectotherm thermoregulatory strategies under extreme cold conditions and experiments testing the effects of cool environments on thermoregulatory behaviour are surprisingly scarce. We conducted laboratory experiments to test if common lizards Zootoca vivipara (an active thermoregulator in the field) are able to switch between active thermoregulation and thermoconformity in response to different thermal environments. We found that lizards in treatments with an opportunity to reach their preferred body temperature thermoregulated accurately, maintained their level of daily activity and improved their body condition considerably. In contrast, lizards in the treatment where the preferred body temperature could not be reached became thermoconformers, decreased their daily activity (except for gravid females) and did not increase their body condition. Our results show that lizards can indeed change their thermoregulatory strategy but stress that maintaining the preferred body temperature and, thus, optimising the physiological performance have high priority in lizard behaviour.