Project tocoen. The fate of selected organic pollutants in the environment—iv. soil,earthworms and vegetation 1988

The samples of soils, earthworms and vegetation (needles, lichens, mosses) were collected for the realization of Project TOCOEN (Toxic Organic Compounds in the ENvironment). The samples were collected from three TOCOEN model areas in Czechoslovakia—one city and two rural areas. The samples were analyzed for polycyclic aromatic hydrocarbons (PAHs), chlorinated pesticides (C1‐PEST) and polychlorinated biphenyls (PCBs).     

Singlet molecular oxygen—mediated photooxidation of monochloro and mononitrophenols. A kinetic study

A kinetic and mechanistic study on the aerobic dye sensitized photooxidation of the mono—nitro and chlorophenols was carried out. A singlet molecular oxygen mechanism operates in the photooxidation. Solvent and substituent effects, suggest the intermediacy of a complex with partial charge transfer character, as has been postulated for other phenols.

Chemical (reactive) and physical interactions of the substrates with singlet molecular oxygen were discriminated. Quantum yields for photooxidation (higher for the chlorophenols) range from 3 × 10^‐2 to 2 × 10^‐3, as measured by substrate or oxygen consumption. These values indicate the viability of a singlet molecular oxygen photooxidation as a way for the degradation of nitro and chlorophenol environmental contaminants.     

Dealing with urban noise: vermilion flycatchers sing longer songs in noisier territories

In noisy conditions, several avian species modulate their songs in amplitude and in the temporal or frequency domains, presumably to improve communication. Most studies on how passerine birds perform such adjustments have been carried out in oscines, a group well known for the importance of learning in the development of their songs. On the other hand, suboscines, in which learning appears to have little influence on the development of their songs, have been largely neglected. We evaluated song adjustment to noise in the vermilion flycatcher (Pyrocephalus rubinus), a suboscine bird. We conducted song recordings and noise measurements at several territories within Mexico City during the length of the dawn chorus. Males living in noisier places sang long songs, while those males inhabiting quieter places sang both short and long songs. We also found evidence of individual song plasticity, as males sang less versatile songs (i.e., songs with more introductory elements) later in the morning when noise levels were higher. This individual shift in song seems to be more associated to time of the day rather than to the observed rise in noise. However, we cannot discard an effect of noise, which should be evaluated with an experiment. We discuss our results in the context of other studies with oscine passerines and other taxa and consider implications for signaling in intra- and intersexual contexts.     

Boldness and body size of male Spanish terrapins affect their responses to chemical cues of familiar and unfamiliar males

Recognition and avoidance of conspecifics based on chemical cues could reduce the risk of aggressive interactions between males. Success in agonistics encounters with unfamiliar males should be lower than with previously known familiar males. Then, males should avoid the chemicals from unfamiliar males with respect to those from familiar males. However, boldness and size could affect the outcome of encounters between males and, consequently, the response to chemical cues of conspecific males. We compared the time spent by male turtles Mauremys leprosa in water pools with chemical stimuli from unfamiliar or familiar males or with their own chemical stimuli. We also performed a behavioral test to estimate boldness of turtles in an antipredatory situation. Turtles avoided the chemicals from unfamiliar males respect to familiar ones and their own odors, but their responses depended on boldness and size of the tested turtle. Bold turtles avoided water with chemicals of unfamiliar males, but not with chemicals of familiar males, whereas shy turtles avoided chemicals of both familiar and unfamiliar males. On the other hand, large males avoided the odor from unfamiliar males, but small males did not avoid water with the odor from other males. Results suggest that male M. leprosa can detect chemicals released to water from conspecific males and discriminate between familiar and unfamiliar males. However, responses to these chemicals depended on boldness and body size of the responding turtle because these factors may affect intrasexual competition.     

Feeding and movement patterns of the sea cucumber Holothuria sanctori

Sea cucumbers are conspicuous organisms inhabiting almost all marine habitats across the globe. Despite their importance as effective consumers of detritus, little is known about their behavior. We studied organic matter (OM) consumption and nocturnal movement patterns of Holothuria sanctori through indoors assays and in situ experiments at shallow bottoms off Gran Canaria Island (Canary Islands, Spain). H. sanctori has a selective feeding toward high OM concentration sediments. Consumption of OM increased with OM availability, particularly during formation of the gonads. OM consumption did not differ in situ between two adjacent habitats arranged in mosaics: macroalgal beds and urchin-grazed “barrens.” Larger distances and fastest displacements were covered by H. sanctori during the end than the middle and start of the nighttime. Overall, we did not detect a clear “homing” behavior by H. sanctori, yet some individuals showed a fidelity for refuges when shelter availability was lacking.     

Temporal patterns of settlement, recruitment and post-settlement losses in a rocky reef fish assemblage in the South-Western Mediterranean Sea

Post-settlement events can significantly alter the density distribution of settlers and subsequently the adult population structure. The temporal and inter-annual variability of settlement and the effects of mortality on recruitment were investigated across 2 years in the vicinities of Cabo de Palos–Islas Hormigas Marine Reserve by visual census and light trap sampling. Settlement was seasonal with greater species richness and abundance in summer. Although temporal synchronization was observed between larval supply and settlement, densities of settlers could not be predicted from post-larval abundances. Timing of settlement was consistent between years but with high inter-annual variation in abundance. High mortality (~80 %) and general decoupling between post-larval and settlement stages suggest that early mortality is driving such patterns. Nevertheless, indications of habitat-mediated mortality were found for benthic species such as Symphodus and Diplodus, highlighting the importance of habitat in shaping population demography.     

Comparison of four methods to estimate meiobenthic copepod Amonardia normani ingestion rates

Four different methods were used in the control conditions of laboratory to estimate the ingestion rate of a female meiobenthic harpacticoid copepod Amonardia normani: (1) reduction of algal biomass, (2) the quantification of total pigments in fecal pellets, (3) the gut fluorescence method, (4) the percentage of assimilation and the total egestion rate. The food used during all experiments was the diatom Nitzschia constricta in an axenic condition at the concentration of 0.13 μg Chl-a mL^?1 at stationary growth phase. All experiments were made at 20 °C and 30 salinity. All tested methods excepted the quantification of total pigments in fecal pellets resulted in similar estimatives. The gut fluorescence method indicated that during the day gut contents are smaller than during the night but the gut passage time was faster, resulting in similar ingestion rates during the day and the night. The reduction of algal biomass and the percentage of assimilation and the total egestion rate also indicated similar ingestion rates in the day and in the night. The daily ingestion rate represents 107 % of female carbon weight per day (903 ng C cop^?1day^?1).     

Biological impacts of ocean acidification: a postgraduate perspective on research priorities

Research into the effects of ocean acidification (OA) on marine organisms has greatly increased during the past decade, as realization of the potential dramatic impacts has grown. Studies have revealed the multifarious responses of organisms to OA conditions, indicating a high level of intra- and interspecific variation in species’ ability to accommodate these alterations. If we are to provide policy makers with sound, scientific input regarding the expected consequences of OA, we need a broader understanding of these predicted changes. As a group of 20 multi-disciplinary postgraduate students from around the globe, with a study focus on OA, we are a strong representation of ‘next generation’ scientists in this field. In this unique cumulative paper, we review knowledge gaps in terms of assessing the biological impacts of OA, outlining directions for future research.     

Possible health impacts of naturally occurring uptake of aristolochic acids by maize and cucumber roots: links to the etiology of endemic (Balkan) nephropathy

Aristolochic acids (AAs) are nephrotoxic and carcinogenic derivatives found in several Aristolochia species. To date, the toxicity of AAs has been inferred only from the effects observed in patients suffering from a kidney disease called “aristolochic acid nephropathy” (AAN, formerly known as “Chinese herbs nephropathy”). More recently, the chronic poisoning with Aristolochia seeds has been considered to be the main cause of Balkan endemic nephropathy, another form of chronic renal failure resembling AAN. So far, it was assumed that AAs can enter the human food chain only through ethnobotanical use (intentional or accidental) of herbs containing self-produced AAs. We hypothesized that the roots of some crops growing in fields where Aristolochia species grew over several seasons may take up certain amounts of AAs from the soil, and thus become a secondary source of food poisoning. To verify this possibility, maize plant (Zea mays) and cucumber (Cucumis sativus) were used as a model to substantiate the possible significance of naturally occurring AAs’ root uptake in food chain contamination. This study showed that the roots of maize plant and cucumber are capable of absorbing AAs from nutrient solution, consequently producing strong peaks on ultraviolet HPLC chromatograms of plant extracts. This uptake resulted in even higher concentrations of AAs in the roots compared to the nutrient solutions. To further validate the measurement of AA content in the root material, we also measured their concentrations in nutrient solutions before and after the plant treatment. Decreased concentrations of both AAI and AAII were found in nutrient solutions after plant growth. During this short-term experiment, there were much lower concentrations of AAs in the leaves than in the roots. The question is whether these plants are capable of transferring significant amounts of AAs from the roots into edible parts of the plant during prolonged experiments.     

Uptake of seven metals by two macrophytes species: potential for phytoaccumulation and phytoremediation

Aquatic macrophytes can be used in the studies of quality of water ecosystems and in monitoring of metals and other pollutants. The aim of this study was to assess concentration levels, accumulation and distribution of seven metals in selected plant parts of Typha angustifolia L. and Iris pseudacorus L., in comparison with sediment and water samples of a reservoir. Metal content in the samples was determined by optical emission spectrometry (ICP-OES iCAP 6500). The concentrations of all examined metals were higher in the sediment than in the water samples. In plants, metal concentrations depended on plant species and organs. The roots/rhizomes were primary organs for metal concentration and accumulation. T. angustifolia L. accumulated Mn and Cu, and I. pseudacorus L. accumulated Cd and Cu in the fruits. T. angustifolia L. hyperaccumulated As. The values of enrichment coefficients and translocation factors were: 0 to 3.31 and 0 to 2.39, respectively. The plant species investigated absorb, translocate and accumulate metals in their organs differently, which provides advantages in combining them for remediation of wasted aquatic ecosystems.