Chlorophenol tolerant and degradative bacteria isolated from a river receiving pulp mill discharges

A screening was carried out in a river receiving pulp mill discharges (BioBio river, central Chile) to study the bacterial population able to tolerate and degrade chlorophenols. In four selected stations and at different seasons, water samples were taken from the river. Total bacterial population and the number of chlorophenol tolerant bacteria were counted. Bacterial tolerance to 25, 50, 100, 200 and 400 μg/ml of 2,4‐dichlorophenol (DCP), 2,4,6‐trichlorophenol (TCP) and pentachlorophenol (PCP) was determined. Strains able to tolerate at least 400 μg/ml chlorophenols were found. Eighteen bacterial strains able to use chlorophenols as the sole carbon source were isolated: five of them were Pseudomonas fluorescens, two Alcaligenes sp., one Citrobacter freundii, one Aeromonas sp. and nine unidentified Gram negative bacilli. A good correlation (r ² = 0.758) between the logarithm of DCP tolerant bacteria and the content of adsorbable organic halogen (AOX) at low dilution in the river water was established. Four groups of tolerant bacteria were found: growing on PCP and DCP, growing on PCP and TCP, growing only on PCP and growing only on TCP.     

Spatial and mass balanced trophic models of La Rinconada Marine Reserve (SE Pacific coast), a protected benthic ecosystem: Management strategy assessment

Steady-state, dynamic, and spatial models were constructed for the benthic system of La Rinconada Marine Reserve off northern Chile (SE Pacific coast). We examined data on biomass, P/B ratios, catches, food spectrum, consumption, and the dynamics of commercial and non-commercial populations using three theoretical frameworks: Ecopath, Ecosim, and Ecospace. The biomass of the scallop Argopecten purpuratus and the clam Tagelus dombeii were the most relevant compartments of the studied ecosystem. Among the carnivores, the functional crab group Cancer spp. was the most relevant. The Rhodophyta was the dominant macroalga compartment of the system. The results obtained using mixed trophic impacts (MTI) showed that the predatory snail Thais chocolata propagated higher magnitudes of direct and indirect effects on the other species or functional groups. The sea star Luidia magallanica and Rhodophyta had the least effects on the remaining compartments. According to the Ecosim estimates (increasing mortality by fishing), the scallop A. purpuratus had the highest impact on the other compartments. The Ecospace model showed similar qualitative and quantitative effects for changes in biomass under three different exploitation scenarios (by subsystems and globally). Nevertheless, the greatest changes were provoked by using the top-down control and the vulnerabilities estimated by Ecosim. System recovery times were highest with increased mortality of the asteroid L. magallanica and the carnivorous snail T. chocolata, suggesting that the sea star could be considered to be a top predator with a top-down control. The F_MSY estimated for the scallop A. purpuratus was close to the F_i originally entered in Ecopath, limiting the design and execution of an exploitation plan within ecologically sustainable boundaries. The situation was different (F_MSY ? F_i) for the other commercial species, making possible multi-species exploitation programs. The Ecospace trophic-spatially explicit model shows a similar pattern of direct and indirect effects generated when exerting exploitation separately by subsystems. Therefore, habitat rotation of fisheries is not justified.     

Neighborhood phylodiversity affects plant performance

Facilitation and competition are ecological interactions that are crucial for the organization of plant communities. Facilitative interactions tend to occur among distantly related species, while the strength of competition tends to decrease with phylogenetic distance. The balance between both types of interactions will ultimately determine the specific composition of multispecies associations. Although multispecies patches are the arena in which coexistence develops among different phylogenetic groups within communities, the specific processes that occur across life stages have not been explored. Here we study how different species, in composing discrete patches in central Mexico, exert competitive or facilitative effects on seeds and seedlings. We relate these interactions to phylogenetic relationships among nurse species and beneficiary species, and among members of the patches. Survivorship and growth rates of the columnar cactus Neobuxbaumia mezcalaensis were highly positively related to increasing phylogenetic distance to different nurse species, to the presence of related species in patches, and to mean phylogenetic distances to the rest of the species in the patch. Each of these three elements influenced N. mezcalaensis differently, with different nurse species varying substantially in their early effects on emergence, and the nearest relatives and species composition of patches varying in their late effects on survival and growth. Our results emphasize that evolutionary relationships among co-occurring species in vegetation clumps exert direct and indirect effects on plants, affecting individual performance and species coexistence.     

Patterns of shelter usage and social aggregation by the vocal Lusitanian toadfish

In some marine fishes, males migrate from deeper to littoral water to breed, where they defend nests and provide parental care. In this study, we describe seasonal patterns of shelter occupation in estuarine shallow waters and assess social aggregation in the Lusitanian toadfish (Batrachoididae), a vocal species with male parental care. Occupation of intertidal shelters was restricted to the breeding season but adult fish remained in subtidal regions during the non-reproductive season and they produced sounds throughout the year. Intertidal shelters were aggregated with up to five shelters found per 2-m segment of an 80-m transect. This aggregation probably resulted from social attraction since many segments were found unoccupied. Moreover, shelters contained on average two fish (maximum of nine). Based on size, shelters with multiple fish seemed to contain females, or possibly sneakers, but also more than one type I male inside, indicating a high social tolerance for conspecifics.     

Shell gaping behaviour of <Emphasis Type="Italic">Pinna nobilis</Emphasis> L., 1758: circadian and circalunar rhythms revealed by in situ monitoring

Gaping activity of bivalve molluscs is closely related to physiological process such as breathing, nutrition, responses to environmental stimuli and follows rhythmic cycles in many species. Although the alternation of Sun and Moon is the major entraining agent for the daily living clock-driven rhythms, cyclic extrinsic environmental factors can also modulate gaping activity. Therefore, laboratory experimental conditions can alter the natural behaviour of bivalves, hindering the interpretation of observations. Many features of Pinna nobilis physiology are poorly known, gaping activity not being an exception. To reduce the knowledge gap on this regard, we performed a study on the species gaping activity. The research was designed to be carried out in situ, in order to avoid the interference of laboratory conditions in the observations. To this end, we designed and fabricated a new electronic system composed by a data logger and a sensor formed by multiple reed switches activated by a single magnet. The system is autonomous and can record gaping activity of subtidal bivalves in potentially any type of subtidal environment. Furthermore, it requires little framework for the installation. With this system, we monitored 10 individuals in periods ranging between 3 and 21 days, for up to a total of 98 days. The records have shown that far from being all day open, as previously suggested, P. nobilis follows marked circadian and circalunar rhythms of gaping activity. Individuals usually close the valves during night, sometimes for more than 12 h. The repetition of patterns observed made it possible to distinguish between two main behaviours: (1) night-closing related with sunset and (2) night-opening related with the Moon visible in the sky with the disc illuminated more than 50%. Another two less common trends were also observed: (3) day-closing and (4) night-opening with no visible Moon.     

Kraft mill residues effects on Monterey pine growth and soil microbial activity

The production of bleached Kraft pulp generates inorganic and organic residues that are usually deposited on the soil surface or land-filled. Studies conducted to address the impact of these wastes on the environment are scarce. In this work, Monterey pine (Pinus radiata D. Don), an important tree for pulping, was evaluated for germination and development under greenhouse conditions in forest soils exposed to solid residues of the cellulose industry using the Kraft process. Soils exposed to 10 to 60% ashes, 10 to 70% fly ashes, or 10 to 30% dregs allowed substantial seed germination and seedling growth. In contrast, soils exposed to low proportions of brown rejects, grits, or a mixture of all these residues were detrimental for germination, plant growth, or both. The strongest negative effect (no germination) was observed with as low as 10% grits. The changes in pH and/or water content caused by solid wastes did not correlate with detrimental effects observed in various soil-residue combinations. No significant changes in the microbial community of soils exposed to these solid residues were observed by determination of culturable counts, or by terminal-restriction fragment length polymorphism analysis of the microbial community DNA. The presence of organic residues did not affect the ability of the soil microbial community to remove typical pulp bleaching chloroaromatics. However, inorganic wastes strongly decreased the removal of such compounds.     

Relationship between soil test phosphorus and phosphorus in runoff: effects of soil series variability

Phosphorus loss in runoff from agricultural fields has been identified as an important contributor to eutrophication. The objective of this research was to determine the relationship between phosphorus (P) in runoff from a benchmark soil (Cecil sandy loam; fine, kaolinitic, thermic Typic Kanhapludult) and Mehlich III-, deionized water-, and Fe(2)O(3)-extractable soil P, and degree of phosphorus saturation (DPS). Additionally, the value of including other soil properties in P loss prediction equations was evaluated. Simulated rainfall was applied (75 mm h(-1)) to 54 1-m(2) plots installed on six fields with different soil test phosphorus (STP) levels. Runoff was collected in its entirety for 30 min and analyzed for total P and dissolved reactive phosphorus (DRP). Soil samples were collected from 0- to 2-, 0- to 5-, and 0- to 10-cm depths. The strongest correlation for total P and DRP occurred with DPS (r(2) = 0.72). Normalizing DRP by runoff depth resulted in improved correlation with deionized water-extractable P for the 0- to 10-cm sampling depth (r(2) = 0.81). The STP levels were not different among sampling depths and analysis of the regression equations revealed that soil sampling depth had no effect on the relationship between STP and P in runoff. For all forms of P in runoff and STP measures, the relationship between STP and runoff P was much stronger when the data were split into groups based on the ratio of oxalate-extractable Fe to Al. For all forms of P in runoff and all STP methods, R(2) increased with the inclusion of oxalate-extractable Al and Fe in the regression equation. The results of this study indicate that inclusion of site-specific information about soil Al and Fe content can improve the relationship between STP and runoff P.     

Life History and Conservation of Totoaba macdonaldi

We conducted a literature review on the biology, ecology, fishery, and protection of totoaba ( Totoaba macdonaldi ), an endemic, threatened fish of the Gulf of Calfornia, Mexico. Reinterpretation and integration of published and unpublished information enabled us to confirm and estimate specific biological parameters of the totooba, make hypothetical constructs of its life history, and to propose ideas for its preservation. In specific, we found (1) that the mean age of first reproduction of male and female totoaba are 6 and 7 years, respectively; (2) that the intrinsic rate of natural mortality was estimated as 0.268 per year and (3) that in the mid 1980s an estimated 120,300 juveniles died each year in the shrimp fishery by-catch and 6200 adults (26 kg average weight) died due to poaching. The parameters of an individual growth model for juveniles and adults were also estimated. Decreased spring water input from the Colorado River into the Gulf of California may have caused a contraction of the spawning season and a reduction of the carrying capacity of juvenile totoaba. An increase in annual survival during recent years indicates recovery of the stock that might be related to protection of adults. We argue that habitat restoration, which includes the elimination of growth and recruitment over-fishing, is critical to increasing numbers of totoaba, and thereby lifting the fishing ban, and to the delisting of totoaba.     

A structural intermediate between triisodontids and mesonychians (Mammalia, Acreodi) from the earliest Eocene of Portugal

A new mammal, Mondegodon eutrigonus gen. et sp. nov., is described from the earliest Eocene locality of Silveirinha, Portugal. This species shows dental adaptations indicative of a carnivorous diet. M. eutrigonus is referred to the order Acreodi and considered, along with the early Paleocene North American species Oxyclaenus cuspidatus, as a morphological intermediate between two groups of ungulate-like mammals, namely, the triisodontids and mesonychians. Considering that triisodontids are early to early-late Paleocene North American taxa, Mondegodon probably belongs to a group that migrated from North America towards Europe during the first part of the Paleocene. Mondegodon could represent thus a relict genus, belonging to the ante-Eocene European mammalian fauna. The occurrence of such a taxon in Southern Europe may reflect a period of isolation of this continental area during the Paleocene/Eocene transition. In this context, the non-occurrence of closely allied forms of Mondegodon in the Eocene North European mammalian faunas is significant. This strengthens the hypothesis that the mammalian fauna from Southern Europe is characterized by a certain degree of endemism during the earliest Eocene. Mondegodon also presents some striking similarities with an unnamed genus from the early Eocene of India which could represent the first Asian known transitional form between the triisodontids and mesonychians.     

Use of blubber levels of progesterone to determine pregnancy in free-ranging live cetaceans

We tested the possibility of measuring progesterone levels in bubbler samples collected from free-ranging live bottlenose dolphins (n = 11) and long-finned pilot whales (n = 2) as a tool to evaluate the pregnancy status of individuals. Samples were collected during January 2004 and September–October 2005 in the Strait of Gibraltar and Gulf of Cadiz and used for sex-determination by genetic methods (skin samples) and for quantification of progesterone levels by enzyme immunoassay. Photo-identification tracking of females after taking the biopsy was used to observe the presence of newborns and, in this way, to determine if the female was pregnant at the time of sampling. Mean progesterone levels from pregnant bottlenose dolphins (n = 2) were around 9 times higher than those from non-pregnant females (n = 9), with no overlap between concentration ranges demonstrating that this method could constitute an effective tool for determining pregnancy in wild populations of bottlenose dolphins and other cetacean species.