Feeding of marine planktonic copepods on mixed phytoplankton

The feeding of juveniles and adults of the copepods Eucalanus pileatus, Temora stylifera and T. turbinata fed a mixture of the phytoplankton Skeletonema costatum, Leptocylindrus danicus and Rhizosolenia alata f. indica was studied at 20°C. E. pileatus nauplii, copepodids and adult females ingest similar percentages of the 3 algae in terms of carbon. Temora juveniles younger than CII ingest mainly S. costatum; at more advanced developmental stages, the ingestion rate on S. costatum remains constant whereas feeding on L. danicus and R. alata f. indica increases with increasing body weight. Feeding on high concentrations of large particles reduces the grazing pressure on small particles, thus favoring zooplankton which require small-sized food.     

Do echolocation calls of wild colony-living Bechstein's bats (Myotis bechsteinii) provide individual-specific signatures?

Social animals often use vocal communication signals that contain individual signatures. As bats emit echolocation calls several times per second to orient in space, these might seem ideal candidates for conveying the caller's individual identity as a free by-product. From a proximate perspective, however, coding of caller identity is hampered by the simple acoustic structure of echolocation signals, by their task-specific design and by propagation loss. We investigated the occurrence of individual signatures in echolocation calls in individually marked, free-living Bechstein's bats (Myotis bechsteinii) in a situation with defined social context in the field. The bats belonged to two different colonies, for both of which genetic data on relatedness structure was available. While our data clearly demonstrate situation specificity of call structure, the evidence for individual-specific signatures was relatively weak. We could not identify a robust and simple parameter that would convey the caller's identity despite the situation-specific call variability. Discriminant function analysis assigned calls to call sequences with good performance, but worsened drastically when tested with other sequences from the same bats. Therefore, we caution against concluding from a satisfactory discrimination performance with identical training and test sequences that individual bats can reliably be told apart by echolocation calls. At least the information contained in a single call sequence seems not to be sufficient for that purpose. Starting frequencies did give the best discrimination between individuals, and it was also this parameter that was correlated with genetic relatedness in one of our two study colonies. Echolocation calls could serve as an additional source of information for individual recognition in Bechstein's bats societies, while it is unlikely that a large number of individuals could be reliably identified in different situations based on echolocation alone.     

Colonization of Europe by two American genetic types or species of the genus Marenzelleria (Polychaeta: Spionidae). An electrophoretic analysis of allozymes

Allozyme electrophoresis was conducted in an attempt to identify the origin ofMarenzelleria sp. found in the North Sea and Baltic Sea. The analysis covered eight enzymes with ten loti from nine populations found on the North American Atlantic toast, these populations in the North Sea and five populations in the Baltic. The North Sea spionids correspond to the Type IMarenzelleria from North American coastal waters between Barnstable Harbor (Massachusetts) and Cape Henlopen (Delaware). Nei's genetic distance between these North American populations and those from the North Sea wasD = 0.010 to 0.020. TheMarenzelleria sp. found in the Baltic Sea very probably stems from North American populations of Type II found from the region of Chesapeake Bay (Trippe Bay) south to the Currituck Sound (North Carolina). The genetic distance between these North American populations and the Baltic populations isD = 0.000 to 0.001. The invaders appear to have lost little of their genetic variation while colonizing the North and Baltic Seas. Probably, both colonizing events tan be attributed to large numbers of individuals reaching Europe simultaneously on one or more occasions. In addition, aMarenzelleria Type III was found by electrophoresis among specimens from Currituck Sound (North Carolina), rohere it is sympatric withMarenzelleria Type II. Salinity is discussed as an important factor for the establishment ofMarenzelleria Type I in the North Sea and Type II in the Baltic Sea.     

Organoiodine formation during humification in peatlands

Although two billion people in the world are suffering from iodine deficiency there is little information on the chemical fate of iodine in the terrestrial environment. Here we show that peatlands play a major role in terrestrial iodine cycling. Chemical data from two peat profiles from Patagonia, Chile imply that transformation of iodine from its inorganic form to organoiodine compounds during early humification in peatlands is a key process in storage of iodine in the terrestrial environment. Once bound in peat, iodine remains stable for thousands of years. In the earths peatlands, net accumulation of iodine since the last glacial period is estimated to be 12–36 teragrams (1 Tg=10¹² g). These data suggest that peatlands are a major reservoir of iodine in terrestrial ecosystems. Our novel model of iodine distribution in the terrestrial environment demonstrates the key role of peatlands in burial and reemission of organically bound iodine.     

Fitness benefits of multiple mating versus female mate choice in the cellar spider (Pholcus phalangioides)

Recent studies have demonstrated that mating with multiple males can be beneficial for females and her offspring even if males contribute nothing but sperm. This was mainly established for species in which sperm from several males mix in the reproductive tract of the female, thus allowing sperm competition and/or female sperm choice. However, in species with last male sperm precedence, female re-mating decides against the previous male by strongly limiting his reproductive success. We tested the effect of female re-mating behaviour using the cellar spider Pholcus phalangioides, which shows strong last males sperm precedence and moderate levels of polyandry under natural situations. We predicted that females prevented from remating even though they are receptive would show reduced reproductive success compared to females that accept two copulations and females that reject a second male, since the latter two treatments were allowed to behave according to their decisions. However, if the number of matings per se had an effect on oviposition or on offspring performance, double-mated females should perform better compared to both treatments of once-mated females. We measured female fecundity and fertility over a period of 140 days, comparable to the species' natural reproductive peak season. Two thousand one hundred and fifty-two offspring from 67 first egg sacs were reared under two feeding levels. We registered development time and survival, and measured offspring adult size and mass. We found a positive effect of double mating, as in this treatment, oviposition probability was higher compared to the other treatments. Interestingly, adult female offspring of the DM treatment that were raised under low food level had a higher condition index compared to those from FS and RM, but development time, size and mass at adulthood were not affected by mating treatment. Female choice only seemed to affect hatching latency of the offspring. Overall, the main predictor of female reproductive output and success was female body size.     

Piercing the partner's skin influences sperm uptake in the earthworm Lumbricus terrestris

Sexual conflict between mating partners can give rise to strategies that are advantageous for one sex but harmful to the opposite sex. Usually, sperm donors develop (offensive) traits to enhance their chances in sperm competition, while sperm recipients evolve (defensive) traits that allow them to stay in control of who fathers their offspring. Here, we demonstrate that these processes are also at work in simultaneous hermaphrodites. The hermaphroditic earthworm Lumbricus terrestris uses 40 to 44 copulatory setae to pierce into its partner's skin, causing damage and injecting a substance from its setal glands. Experimental injection of the gland substance indicates that a refractory period may be induced. More importantly, removal of the copulatory setae shows that they influence the partner's sperm uptake. When the setae are present, more sperm are taken up and sperm are distributed more equally over the four spermathecae. We interpret this as a strategy that stacks the odds for the donor's sperm in fertilizing cocoons.     

Metabolism of a nonylphenol isomer by Sphingomonas sp. strain TTNP3

For elucidation of the metabolism of the endocrine disruptor nonylphenol by Sphingomonas sp. strain TTNP3, the degradation of an isomer of nonylphenol, 4(2,6-dimethyl-2-heptyl)-phenol, has been studied. As in the case of 4(3,5-dimethyl-3-heptyl)-phenol, the metabolism of this nonylphenol isomer leads to the formation of the NIH-shifted product 2(2,6-dimethyl-2-heptyl)-1,4-benzenediol (NIH: National Institute of Health), but also to the alkoxy derivative 4(2,6-dimethylheptan-2-yloxy)phenol as additional metabolite. To the best of our knowledge, this is the first report describing the formation of alkoxyphenol as a degradation product of nonylphenol. Additionally, these results provide for the first time evidence for slight differences in the biodegradation of the isomers of nonylphenol.     

Charakterisierung von Holzasche aus Biomassefernheizwerken

Analyses of ashes from wood chips and bark combustion and research work about possibilities of utilization of these ashes showed that in general a mixture of bottom ash and cyclon fly-ash in the ratio as they occur in the plant can be used as a fertilizer and liming material. An important question is whether mineral impurities (sand, earth, stones) in the biomass are responsible for slagging on the grate (by lowering the melting point) because sintered and slagged ash with a particle size larger than 2 cm has to be sieved or milled before utilized. Furthermore, the influence of these impurities on the homogeneity of wood ash is important for taking and preparing samples for analysis. Usually, the occurring ash fractions in biomass district heating plants can only be volumetrically measured. In order to determine the actual mass flow and to proportion the ash-amounts for fertilization properly, it is necessary to know the bulk densities of the different ash fractions in dependence on the particle size and the biomass used. Moreover, the knowledge of the surface properties of fly-ash particles enables to evaluate the influencing variables on the process of heavy metal deposition from the flue gas to the fly-ash particles. This information represents the basis for a fractionated desublimation/condensation of heavy metals. The aim is to concentrate them in the filter fly-ash, because this smallest and finest ash fraction is cut off from the ash cycle and is disposed of. Conforming to these open questions, ashes from biomass district heating plants were examined. The facts and findings obtained represent the basis for technological measures in order to improve a closed cycle economy with wood ash.     

Adaptation of the polychaete worm Scoloplos armiger to hypoxic conditions

The anaerobic metabolism of the intertidal polychaete Scoloplos armiger, its recovery from anaerobiosis and the importance of anaerobic energy production during low tide in the field were investigated. Under anaerobic conditions S. armiger produces energy in the same manner as Arenicola marina, a prototype of an euryoxic invertebrate from the intertidal. Energy is produced from the phosphagen stores and from the breakdown of glycogen to volatile fatty acids, mainly propionate and to a lesser extend acetate. However, S. armiger cannot reduce its energy demand to the same degree as A. marina. This and the relatively small pool of glycogen may be the reason for its only moderate resistance to anoxia. The recovery from anaerobiosis proceeds in S. armiger significantly slower than in A. marina. S. armiger is able to maintain a fully aerobic metabolism down to a Pw_{O 2}of ca. 20 torr and even at a Pw_{O 2}of 10 torr a partly aerobic metabolism was retained. In the field during low tide S. armiger ascends into the oxidative layer, where it is able to maintain an aerobic metabolism even at parts without remaining puddels on the surface.