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The Science of Nature -     

Quantitative Bestimmung des lokalen Flusses mit elektrochemisch erzeugtem Wasserstoff

The Science of Nature -     

Wassertechnische Strategien zur Reduzierung der Trinkwasserbelastung durch Arzneimittelwirkstoffe

Results The available research results concerning the application of innovative methods of wastewater and drinking water purification to eliminate pharmaceuticals are summarized in the present paper. An increase of the activated sludge (aerobic sludge) age to 8–10 days in treatment plants can improve the metabolization of less persistent pharmaceutical agents whereas expansion of the sojourn time beyond 10 days will not result in a remarked increase of degradation for most pharmaceutical substances. First results have shown that wastewater treatment plants with integrated membrane bioreactors (MBR) using micro- and ultrafiltration membranes do not provide significantly better results compared to the conventional wastewater treatment plants with respect to the removal of organic micropollutants (including pharmaceutical residues). The use of powdered carbon in biologically treated wastewater is able to reduce pharmaceutical residues up to 80?% in the run-off water. Pilot studies scrutinize the treatment of highly contaminated effluents via catalytic photooxidation. Regarding the suitability of the method to reduce the contamination of drinking and wastewater with pharmaceuticals yet only few data from laboratory scale testing are available. Activated carbon filtration is preferably used for drinking water treatment. Primarily against the background of disinfection, ozonation is widely used for drinking water treatment, but for wastewater treatment the method is still at the experimental stage and will hardly become of practical importance because of high costs. Sustainable wastewater separation is grounded on decentralized concepts by considering material cycles (recycling) at the place of origin. In the long term, separation measures can significantly contribute to declining drug concentrations in drinking water. Regarding the quarrying of drinking water by bank filtration water, river water or artificially enriched ground water, end-of-pipe techniques are vital. Most commonly, activated carbon or activated carbon combined with ozonization is applied and assures a high drinking water quality. Discussion The advantages and disadvantages of the different water treatment methods mainly concern the varying degrees of effectiveness with respect to the elimination of very persistent pharmaceutical agents, the generation of problematical metabolites and additional waste materials, hygienic problems, energy needs and the necessity to employ appropriate technical staff for operation. Although the biodegradation of very persistent drugs cannot be enhanced by an extension of the activated sludge age, this modification should be considered in sewage plants to reduce the contamination with less persistent medical agents. Compared with conventional wastewater treatment, membrane bioreactors provide the advantage of a better control of biological activities on the plant and a comparably small plant size but high investment and operation costs. Additionally, pharmaceuticals such as carbamazepin are only insufficiently removed from wastewater by membrane bioreactors. The regular use of powdered activated carbon in sewage treatment plants would also increase the costs of wastewater treatment and would additionally exclude the further use of sewage sludge in agriculture. Currently, in Germany the further use of sewage sludge is handled differently by the Federal States and discussed controversially. The implementation of ozonation as an additional treatment method in wastewater treatment plants is not realistic because of cost concerns. Additionally, the method produces analytically as yet not assessed metabolites with unknown (eco-)toxicological impacts. For this reason ozonation should currently not be applied unless the reaction products are removed subsequently by filtration through activated carbon. For industrial sewage photooxidation is in a state of testing but an application for municipal wastewater is, up to now, out of question. When river bank filtration is used for the supply of drinking water the use of activated carbon for purification should be essential. The lifetime of the filters is often defined by the filter capacities to eliminate radiocontrast media (e.?g., iopamidole, amidotrizoic acid). Many water supply companies already apply the ozonization prior to activated carbon filtration which supports the elimination of pharmaceuticals from the sewage. The unique developmental potential of the wastewater separation can be seen in the possibility to link up these methods with sustainable exploitation techniques and concepts (re-use of sanitized water, production of fertilizer, compost and biogas). Wastewater separation will not make ‘middle/end-of-pipe’ techniques dispensable but will make their handling more effective because concentrations of pharmaceutical agents are higher in separated effluents compared to those usually found in municipal wastewater, which in mixing sewage systems is even diluted by surface runoff. Conclusions Following today’s state of knowledge activated carbon filtration (eventually coupled with ozonization) is best suited to remove drug residues and other xenobiotics from raw water. Water works that do not apply the activated carbon filtration technique for cleanup of bank filtration water should consider an upgrade. The ozonization is primarily required for disinfection of the water. As no acute health hazard proceeds from drinking water contamination by pharmaceuticals at the present time, the upgrade of wastewater treatment plants by one of the aforementioned innovative methods is currently not required in view of drinking water quality. This offers the opportunity to develop sustainable approaches that already aim to reduce drug contaminations of wastewater and hence of ground-, surface- and drinking water. Recommendations and perspectives On a short- to mid-term perspective enriched sewage of hospitals, nursing homes and other medical facilities should be collected and treated separately. From a technical point of view the conditioning of separated hospital effluents (yellow- and greywater) via activated carbon or membrane filtration is possible but should be combined with disinfection. On a mid- and long-term scale sustainable sanitary concepts based on wastewater separation (black-, grey- and/or rainwater) associated with the recycling of mineral nutrients (nitrogen, phosphorous and potassium) should be realized for development, industry and trade areas, buildings with public lavatories, airports, motorway service areas, and large office and hotel buildings. Strategies focusing primarily on up-grading of municipal wastewater treatment plants are currently existing but the related technologies are largely in a test phase. This is why a particular technique should not be favored at the moment. The combination of various techniques (i.?e., ozonization combined with activated carbon filtration) is known to be very efficient for the removal of pharmaceutical residues from water, but the combination cannot be expected to become of importance in treatment of domestic wastewater because of high costs. Moreover, improvement of wastewater treatment technologies to remove pharmaceutical residues will not make the employment of end-of-pipe techniques in water works redundant and therefore will not lead to saving of expenses.     

Annual population development and production by small copepods in Disko Bay,western Greenland

The population of small copepod species (approximately <1 mm) were investigated during an annual cycle in Disko Bay, western Greenland. The small species considered were Acartia longiremis, Pseudocalanus spp., Oithona spp., Oncaea spp., Microsetella spp., and Microcalanus spp. Most of the small species were present in the surface waters year round and numerically dominated the community, and in biomass from late summer and throughout winter. Oithona spp. was numerically the main contributor, while Pseudocalanus spp. dominated in terms of biomass. In the uppermost 50 m, maximum abundance, biomass and secondary production were observed in late September after the phytoplankton production practically had terminated and the winter initiated. The free spawning Acartia longiremis showed a strong seasonal fluctuation in biomass and egg production, in contrast to the egg carrying species Pseudocalanus spp. and Oithona spp. These had a long spawning season and maintained a more stable biomass year round. Secondary production was estimated by three different ways: (1) based on the obtained specific egg production rates, (2) a temperature dependent equation, and (3) a multilinear regression taking temperature, body weight and chlorophyll into consideration. The contribution of the small species was insignificant when compared to the large Calanus species during the spring- and post-bloom. However, during late summer and winter, where Calanus had left the upper water strata for hibernation, the small species played a crucial role in the pelagic carbon cycling.     

Molecular dating and biogeography of the neritic krill Nyctiphanes

The genus Nyctiphanes (Malacostraca, Euphausiacea) comprises four neritic species that display antitropical geographic distribution in the Pacific (N. simplex and N. australis) and Atlantic (N. couchii and N. capensis) Oceans. We studied the origin of this distribution applying methods for phylogenetic reconstruction and molecular dating of nodes using a Bayesian MCMC analysis and the DNA sequence information contained in mtDNA 16S rDNA and cytochrome oxidase (COI). We tested hypotheses of vicariance by contrasting the time estimates of cladogenesis with the onset of the major barriers to ocean circulation. It was estimated that Nyctiphanes originated in the Pacific Ocean during the Miocene, with a lower limit of 18 miilion years ago (Mya). An Atlantic–Pacific cladogenic event (95% HPD 3.2–9.6) took place after the closure of the Tethyan Sea, suggesting that dispersal occurred from the Indo-Pacific, most likely via southern Africa. Similarly, the antitropical distribution pattern observed in the eastern Atlantic Ocean likely resulted from recent Pliocene–Pleistocene (95% HPD 1.0–4.97) northward dispersal from the southern hemisphere. Our results imply that dispersal appears to have had a significant role to play in the evolution of this group. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Southern Ocean biogeography and taxonomic resolution: what’s in the name?

We examined the taxonomic resolution of zooplankton data required to identify ocean basin scale biogeographic zonation in the Southern Ocean. A 2,154 km transect was completed south of Australia. Sea surface temperature (SST) measured at 1 min intervals showed that seven physical zones were sampled. Zooplankton were collected at a spatial resolution of ~9.2 km with a continuous plankton recorder, identified to the highest possible taxonomic resolution and enumerated. Zooplankton assemblage similarity between samples was calculated using the Bray–Curtis index for the taxonomic levels of species, genus, family, order and class after first log₁₀(x + 1) (LA) and then presence/absence (PA) transformation of abundance data. Although within and between zone sample similarity increased with decreasing taxonomic resolution, for both data transformations, cluster analysis demonstrated that the biogeographic separation of zones remained at all taxonomic levels when using LA data. ANOSIM confirmed this, detecting significant differences in zooplankton assemblage structure between all seven a priori determined physical zones for all taxonomic levels when using the LA data. In the case of the PA data for the complete data set, and both LA and PA data for a crustacean only data set, no significant differences were detected between zooplankton assemblages in the Polar frontal zone (PFZ) and inter-PFZ at any taxonomic level. Loss of information at resolutions below the species level, particularly in the PA data, prevented the separation of some zones. However, the majority of physical zones were biogeographically distinct from species level to class using both LA and PA transformations. Significant relationships between SST and zooplankton community structure, summarised as NMDS scores, at all taxonomic levels, for both LA and PA transformations, and complete and crustacean only data sets, highlighted the biogeographic relevance of low resolution taxonomic data. The retention of biogeographic information in low taxonomic resolution data shows that data sets collected with different taxonomic resolutions may be meaningfully merged for the post hoc generation of Southern Ocean time series.     

Lipid and protein utilisation during early development of yellowtail kingfish (<Emphasis Type="Italic">Seriola lalandi</Emphasis>)

The pelagic yellowtail kingfish Seriola lalandi has become a target species for aquaculture in Asia and Australasia. Australasian production is reliant on larviculture from eggs of captive brood stock; however, knowledge regarding the nutritional requirements of larvae of this species is still scarce, particularly in relation to lipids. As a first step in establishing these requirements, eggs and larvae from captive S. lalandi brood stock were examined for differences in total protein, total lipid and lipid classes between individual spawning events, over the spawning season, and during larval development from fertilisation to 15 days post hatch. Results indicate that total protein egg⁻¹ varied significantly between individual spawning events within a season, but neither total lipid nor total protein egg⁻¹ varied significantly across the spawning season. Brood stock egg lipids were made up of approximately 60% phospholipid, 25% wax and/or sterol esters (WE), 15% triacylglycerol (TAG), and small amounts of sterols and free fatty acids. During the early larval period, both WE and TAG were utilised concurrently for energy. The larvae experienced very high mortality around 5–7 days post hatch, which coincided with very low levels of all neutral lipid classes. Although many other factors may also influence larval mortality, these results indicate that lipid provisioning may be an important factor in larval survival during the critical period around first-feeding in this species. Examination of ratios of TAG:ST, often used as a condition index in fish larvae, suggested that some of the larvae were suffering from starvation. However, as egg-derived WE appears to provide a significant source of energy during the early larval period in S. lalandi, it is suggested that WE should be included in any index of larval nutritional state.     

Effects of climate change on phenology, frost damage, and floral abundance of montane wildflowers

The timing of life history traits is central to lifetime fitness and nowhere is this more evident or well studied as in the phenology of flowering in governing plant reproductive success. Recent changes in the timing of environmental events attributable to climate change, such as the date of snowmelt at high altitudes, which initiates the growing season, have had important repercussions for some common perennial herbaceous wildflower species. The phenology of flowering at the Rocky Mountain Biological Laboratory (Colorado, USA) is strongly influenced by date of snowmelt, which makes this site ideal for examining phenological responses to climate change. Flower buds of Delphinium barbeyi, Erigeron speciosus, and Helianthella quinquenervis are sensitive to frost, and the earlier beginning of the growing season in recent years has exposed them to more frequent mid-June frost kills. From 1992 to 1998, on average 36.1% of Helianthella buds were frosted, but for 1999-2006 the mean is 73.9%; in only one year since 1998 have plants escaped all frost damage. For all three of these perennial species, there is a significant relationship between the date of snowmelt and the abundance of flowering that summer. Greater snowpack results in later snowmelt, later beginning of the growing season, and less frost mortality of buds. Microhabitat differences in snow accumulation, snowmelt patterns, and cold air drainage during frost events can be significant; an elevation difference of only 12 m between two plots resulted in a temperature difference of almost 2 degrees C in 2006 and a difference of 37% in frost damage to buds. The loss of flowers and therefore seeds can reduce recruitment in these plant populations, and affect pollinators, herbivores, and seed predators that previously relied on them. Other plant species in this environment are similarly susceptible to frost damage so the negative effects for recruitment and for consumers dependent on flowers and seeds could be widespread. These findings point out the paradox of increased frost damage in the face of global warming, provide important insights into the adaptive significance of phenology, and have general implications for flowering plants throughout the region and anywhere climate change is having similar impacts.