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The snow leopard (Panthera uncia) is one of the world's most elusive felids. In Bhutan, which is one of the 12 countries where the species still persists, reliable information on its distribution and habitat suitability is lacking, thus impeding effective conservation planning for the species. To fill this knowledge gap, we created a country-wide species distribution model using “presence-only” data from 420 snow leopard occurrences (345 from a sign survey and 77 from a camera-trapping survey) and 12 environmental covariates consisting of biophysical and anthropogenic factors. We analyzed the data in an ensemble model framework which combines the outputs from several species distribution models. To assess the adequacy of Bhutan's network of protected areas and their potential contribution toward the conservation of the species, we overlaid the output of the ensemble model on the spatial layers of protected areas and biological corridors. The ensemble model identified 7,206 km2 of Bhutan as suitable for the snow leopard: 3,647 km2 as highly suitable, 2,681 km2 as moderately suitable, and 878 km2 as marginally suitable. Forty percent of the total suitable habitat consisted of protected areas and a further 8% of biological corridors. These suitable habitats were characterized by a mean livestock density of 1.3 individuals per hectare, and a mean slope of 25°; they closely match the distribution of the snow leopard's main wild prey, the bharal (Pseudois nayaur). Our study shows that Bhutan's northern protected areas are a centre for snow leopard conservation both at the national and regional scale.

The study of mammals has promoted the development and testing of many ideas in contemporary ecology. Here we address recent developments in foraging and habitat selection, source–sink dynamics, competition (both within and between species), population cycles, predation (including apparent competition), mutualism, and biological invasions. Because mammals are appealing to the public, ecological insight gleaned from the study of mammals has disproportionate potential in educating the public about ecological principles and their application to wise management. Mammals have been central to many computational and statistical developments in recent years, including refinements to traditional approaches and metrics (e.g., capture-recapture) as well as advancements of novel and developing fields (e.g., spatial capture-recapture, occupancy modeling, integrated population models). The study of mammals also poses challenges in terms of fully characterizing dynamics in natural conditions. Ongoing climate change threatens to affect global ecosystems, and mammals provide visible and charismatic subjects for research on local and regional effects of such change as well as predictive modeling of the long-term effects on ecosystem function and stability. Although much remains to be done, the population ecology of mammals continues to be a vibrant and rapidly developing field. We anticipate that the next quarter century will prove as exciting and productive for the study of mammals as has the recent one.

Ever-increasing human pressures on cave biodiversity have amplified the need for systematic, repeatable, and intensive surveys of cave-dwelling arthropods to formulate evidence-based management decisions. We examined 110 papers (from 1967 to 2018) to: (i) understand how cave-dwelling invertebrates have been sampled; (ii) provide a summary of techniques most commonly applied and appropriateness of these techniques, and; (iii) make recommendations for sampling design improvement. Of the studies reviewed, over half (56) were biological inventories, 43 ecologically focused, seven were techniques papers, and four were conservation studies. Nearly one-half (48) of the papers applied systematic techniques. Few papers (24) provided enough information to repeat the study; of these, only 11 studies included cave maps. Most studies (56) used two or more techniques for sampling cave-dwelling invertebrates. Ten studies conducted ≥10 site visits per cave. The use of quantitative techniques was applied in 43 of the studies assessed. More than one-third (42) included some level of discussion on management. Future studies should employ a systematic study design, describe their methods in sufficient detail as to be repeatable, and apply multiple techniques and site visits. This level of effort and detail is required to obtain the most complete inventories, facilitate monitoring of sensitive cave arthropod populations, and make informed decisions regarding the management of cave habitats. We also identified naming inconsistencies of sampling techniques and provide recommendations towards standardization.

Life-history adaptations to environmental change can be studied retrospectively in organisms that produce dormant propagules using methods of resurrection ecology. Here, we investigated such responses in a planktonic freshwater rotifer, Brachionus calyciflorus. We resurrected 14 clonal lineages from resting eggs extracted from three distinct sediment layers--representing periods of high, medium and low copper pollution--of a previously contaminated lake (Lake Orta, Italy). We exposed the resurrected clones to four copper concentrations over 14 days and recorded population densities at 48 h intervals. If the original populations in Lake Orta had adapted to the changing pollution levels, we expected to find demographic evidence of this adaptation in the resurrected lineages. However, we found high clonal variation in population-growth dynamics, which was more pronounced within than between pollution periods. Moreover, intrinsic population growth rates (r) increased chronologically. As such, the results did not reveal signs of adaptive evolution. Furthermore, we found that lineages from the period of medium copper pollution invested less into sexual reproduction than lineages from the other periods. By using this bio-demographic perspective, our analysis of resurrected rotifers provides insights into the life-history responses of an aquatic invertebrate in an ever-changing environment.

Highlights • Sulphidic event on the shelf resulted in a temporal imbalance of the benthic N cycle. • Bacterial NOx storage is a major source of oxidative power during euxinia. • Peruvian shelf and upper slope sediments are strong recycling sites of fixed N. Abstract Oxygen minimum zones (OMZ) are key regions for fixed nitrogen loss in both the sediments and the water column. During this study, the benthic contribution to N cycling was investigated at ten sites along a depth transect (74–989 m) across the Peruvian OMZ at 12 °S. O2 levels were below detection limit down to ~ 500 m. Benthic fluxes of N2, NO3–, NO2–, NH4+, H2S and O2 were measured using benthic landers. Flux measurements on the shelf were made under extreme geochemical conditions consisting of a lack of O2, NO3– and NO2– in the bottom water and elevated seafloor sulphide release. These particular conditions were associated with a large imbalance in the benthic nitrogen cycle. The sediments on the shelf were densely covered by filamentous sulphur bacteria Thioploca, and were identified as major recycling sites for DIN releasing high amounts of NH4+up to 21.2 mmol m−2 d−1 that were far in excess of NH4+release by ammonification. This difference was attributed to dissimilatory nitrate (or nitrite) reduction to ammonium (DNRA) that was partly being sustained by NO3– stored within the sulphur oxidizing bacteria. Sediments within the core of the OMZ (ca. 200 to 400 m) also displayed an excess flux of N of 3.5 mmol m−2 d−1 mainly as N2. Benthic nitrogen and sulphur cycling in the Peruvian OMZ appears to be particularly susceptible to bottom water fluctuations in O2, NO3−and NO2−, and may accelerate the onset of pelagic euxinia when NO3−and NO2−become depleted.

The squat lobster Pleuroncodes monodon is a key species of the highly productive, but oxygen-poor upwelling system of the Eastern Tropical South Pacific. Observations of P. monodon in the water column off Peru have led to the hypothesis that anoxic conditions force this otherwise primarily benthic species to adopt a pelagic lifestyle. Here we show that off Peru, P. monodon can be found in the oxygenated surface water, but also on the anoxic seafloor. Our physiological experiments demonstrate that juvenile and adult specimens have a very low critical respiratory pO(2) of 0.5 kPa and that adults survive anoxia for 30.5-70.5 h. Anoxic conditions at the seafloor should therefore force P. monodon to regularly migrate to the oxic surface layer in order to restore energy reserves and recycle metabolic end products of anaerobic metabolism. It was recently estimated that the ammonium supply mediated by diel vertical migrations (DVMs) of zooplankton and nekton considerably fuels bacterial anaerobic ammonium oxidation-a major loss process for fixed nitrogen in the ocean. These estimates were based on the implicit assumption that anoxia does not result in a down-regulation of ammonium excretion. We here show that exposure to anoxia elicits a fourfold reduction in ammonium excretion from 2.1 +/- 0.6 mu mol h(-1) g dry weight(-1) under normoxic to 0.5 +/- 0.6 mu mol h(-1) g DW-1 under anoxic conditions in P. monodon. Estimates of ammonium supply to the anoxic core of oxygen minimum zones via DVM therefore are likely too high.

Caves are considered buffered environments in terms of their ability to sustain near-constant microclimatic conditions. However, cave entrance environments are expected to respond rapidly to changing conditions on the surface. Our study documents an assemblage of endemic arthropods that have persisted in Rapa Nui caves, despite a catastrophic ecological shift, overgrazing, and surface ecosystems dominated by invasive species. We discovered eight previously unknown endemic species now restricted to caves-a large contribution to the island's natural history, given its severely depauperate native fauna. Two additional species, identified from a small number of South Pacific islands, probably arrived with early Polynesian colonizers. All of these animals are considered disturbance relicts-species whose distributions are now limited to areas that experienced minimal historical human disturbance. Extinction debts and the interaction of global climate change and invasive species are likely to present an uncertain future for these endemic cavernicoles.

During the discovery and description of seven New Zealand methane seep sites, an infaunal assemblage dominated by ampharetid polychaetes was found in association with high seabed methane emission. This ampharetid-bed assemblage had a mean density of 57,000 6 7800 macrofaunal individuals m22 and a maximum wet biomass of 274 g m22, both being among the greatest recorded from deep-sea methane seeps. We investigated these questions: Does the species assemblage present within these ampharetid beds form a distinct seep community on the New Zealand margin? and What type of chemoautotrophic microbes fuel this heterotrophic community? Unlike the other macro-infaunal assemblages, the ampharetid-bed assemblage composition was homogeneous, independent of location. Based on a mixing model of species-specific mass and isotopic composition, combined with published respiration measurements, we estimated that this community consumes 29–90 mmol C m22 d21 of methane-fueled biomass; this is . 290 times the carbon fixed by anaerobic methane oxidizers in these ampharetid beds. A fatty acid biomarker approach supported the finding that this community, unlike those previously known, consumes primarily aerobic methanotrophic bacteria. Due to the novel microbial fueling and high methane flux rates, New Zealand’s ampharetid beds provide a model system to study the influence of metazoan grazing on microbially mediated biogeochemical cycles, including those that involve greenhouse gas emissions.

A method is described to assess the reproductive status of male Hippocampus abdominalis on the basis of behavioural traits. The non-invasive nature of this technique minimizes handling stress and reduces sampling requirements for experimental work. It represents a useful tool to assist researchers in sample collection for studies of reproduction and development in viviparous syngnathids, which are emerging as important model species.

This study presents benthic data from 12 samplings from February to December 2010 in a 28 m deep channel in the southwest Baltic Sea. In winter, the distribution of solutes in the porewater was strongly modulated by bioirrigation which efficiently flushed the upper 10 cm of sediment, leading to concentrations which varied little from bottom water values. Solute pumping by bioirrigation fell sharply in the summer as the bottom waters became severely hypoxic (< 2 μM O2). At this point the giant sulfide-oxidizing bacteria Beggiatoa was visible on surface sediments. Despite an increase in O2 following mixing of the water column in November, macrofauna remained absent until the end of the sampling. Contrary to expectations, metabolites such as dissolved inorganic carbon, ammonium and hydrogen sulfide did not accumulate in the upper 10 cm during the hypoxic period when bioirrigation was absent, but instead tended toward bottom water values. This was taken as evidence for episodic bubbling of methane gas out of the sediment acting as an abiogenic irrigation process. Porewater–seawater mixing by escaping bubbles provides a pathway for enhanced nutrient release to the bottom water and may exacerbate the feedback with hypoxia. Subsurface dissolved phosphate (TPO4) peaks in excess of 400 μM developed in autumn, resulting in a very large diffusive TPO4 flux to the water column of 0.7 ± 0.2 mmol m−2 d−1. The model was not able to simulate this TPO4 source as release of iron-bound P (Fe–P) or organic P. As an alternative hypothesis, the TPO4 peak was reproduced using new kinetic expressions that allow Beggiatoa to take up porewater TPO4 and accumulate an intracellular P pool during periods with oxic bottom waters. TPO4 is then released during hypoxia, as previous published results with sulfide-oxidizing bacteria indicate. The TPO4 added to the porewater over the year by organic P and Fe–P is recycled through Beggiatoa, meaning that no additional source of TPO4 is needed to explain the TPO4 peak. Further experimental studies are needed to strengthen this conclusion and rule out Fe–P and organic P as candidate sources of ephemeral TPO4 release. A measured C/P ratio of < 20 for the diffusive flux to the water column during hypoxia directly demonstrates preferential release of P relative to C under oxygen-deficient bottom waters. This coincides with a strong decrease in dissolved inorganic N/P ratios in the water column to ~ 1. Our results suggest that sulfide oxidizing bacteria could act as phosphorus capacitors in systems with oscillating redox conditions, releasing massive amounts of TPO4 in a short space of time and dramatically increasing the internal loading of TPO4 to the overlying water.

The sediment-water interface is an important site for material exchange in marine systems and harbor unique microbial habitats. The flux of nutrients, metals, and greenhouse gases at this interface may be severely dampened by the activity of microorganisms and abiotic redox processes, leading to the "benthic filter" concept. In this study, we investigate the spatial variability, mechanisms and quantitative importance of a microbially-dominated benthic filter for dissolved sulfide in the Eastern Gotland Basin (Baltic Sea) that is located along a dynamic redox gradient between 65 and 173m water depth. In August-September 2013, high resolution (0.25 mm minimum) vertical microprofiles of redox-sensitive species were measured in surface sediments with solid-state gold-amalgam voltammetric microelectrodes. The highest sulfide consumption (2.73-3.38 mmol m(-2) day(-1)) occurred within the top 5 mm in sediments beneath a pelagic hypoxic transition zone (HTZ, 80-120m water depth) covered by conspicuous white bacterial mats of genus Beggiatoa. A distinct voltammetric signal for polysulfides, a transient sulfur oxidation intermediate, was consistently observed within the mats. In sediments under anoxic waters (> 140m depth), signals for Fe(II) and aqueous FeS appeared below a subsurface maximum in dissolved sulfide, indicating a Fe(II) flux originating from older sediments presumably deposited during the freshwater Ancylus Lake that preceded the modern Baltic Sea. Our results point to a dynamic benthic sulfur cycling in Gotland Basin where benthic sulfide accumulation is moderated by microbial sulfide oxidation at the sediment surface and FeS precipitation in deeper sediment layers. Upscaling our fluxes to the Baltic Proper; we find that up to 70% of the sulfide flux (2281 kton yr(-1)) toward the sediment-seawater interface in the entire basin can be consumed at the microbial mats under the HTZ (80-120m water depth) while only about 30% the sulfide flux effuses to the bottom waters (> 120m depth). This newly described benthic filter for the Gotland Basin must play a major role in limiting the accumulation of sulfide in and around the deep basins of the Baltic Sea.

The potential coupling of nitrogen (N2) fixation and sulfate reduction (SR) was explored in sediments of the Peruvian oxygen minimum zone (OMZ). Sediment samples were retrieved by a multiple corer at six stations along a depth transect (70–1025 m water depth) at 12° S, covering anoxic and hypoxic bottom water conditions. Benthic N2 fixation, determined by the acetylene reduction assay, was detected at all sites, with highest rates between 70 and 253 m and lower rates at greater depth. SR rates decreased with increasing water depth. N2 fixation and SR overlapped in sediments, suggesting a potential coupling of both processes. However, a weak positive correlation of their activity distribution was detected by principle component analysis. A potential link between N2 fixation and sulfate-reducing bacteria was indicated by the molecular analysis of nifH genes. Detected nifH sequences clustered with the sulfate-reducing bacteria Desulfonema limicola at the 253 m station. However, nifH sequences of other stations clustered with uncultured organisms, Gammaproteobacteria, and Firmicutes (Clostridia) rather than with known sulfate reducers. The principle component analysis revealed that benthic N2 fixation in the Peruvian OMZ is controlled by organic matter (positive) and free sulfide (negative). No correlation was found between N2 fixation and ammonium concentrations (even at levels > 2022 µM). N2 fixation rates in the Peruvian OMZ sediments were in the same range as those measured in other organic-rich sediments.

A characteristic feature of the Daphnia (Crustacea: Cladocera) life cycle are the so-called ephippia, which are fertilised eggs that need to undergo diapause. When they are shed by the female, they sink to the lake bottom, where they may become embedded in the sediment and may remain viable for decades. Extracting and hatching ephippia in the laboratory and subjecting resurrected lineages to conditions representative of historic lake environments allows retrospective investigation of life-history responses to environmental change. Here we reanalyse data from such a resurrection experiment (Piscia et al., 2015: Bull. Environ. Contam. Toxicol. 94:46–51). Contemporary and past lineages of Daphnia galeata Sars 1863 were obtained from Lake Orta (Italy), a deep, subalpine lake with a well-documented history of industrial copper pollution. Experimental Daphnia were subjected to three copper treatments representative of two levels of historic as well as to current (i.e., unpolluted) lake conditions, and life-table data were collected. With these data at hand, we first estimated vital rates (survival, maturation, and reproduction) and used these rates to project the asymptotic population growth rates (λ) for each population-by-treatment combination. Next, we performed life-table response experiments (LTRE) to estimate the contributions of the vital rates to observed differences in λ. Finally, we used elasticity analysis to explore the functional relationship between λ and each of the vital rates. We found that survival rates were only compromised at elevated copper levels. Moreover, past, resurrected Daphnia had a higher λ at low copper concentrations compared to unpolluted conditions, but a lower λ when exposed to high copper levels. Contemporary Daphnia, on the other hand, only reproduced successfully in unpolluted water. Under these conditions, however, they had a higher population growth rate than the past Daphnia, suggesting a cost of copper tolerance in the latter. This cost was mainly due to a lower probability of reproduction and reduced fecundity, whereas survival remained largely unaffected. Finally, we found higher elasticity values of λ to survival than to reproductive rates. This suggests that any change in the environment that will affect survival rather than reproductive parameters will have a much larger impact on Lake Orta’s current Daphnia population.

Lake Orta experienced for a few decades a unique history of chronic pollution, with extreme changes in pH and copper concentration. Currently, the lake has recovered to its almost pristine oligotrophic conditions, but its sediments still preserve the record of all the changes that happened since the establishment of the first polluting factories in the 1920s, through to the liming activities in 1989-1990, and to the recovery phase that is still going on. Here we review the current knowledge for Lake Orta regarding rotifers, a diverse component of the zooplankton of the lake, through studies on living organisms and on their resting stages accumulated in the sediments. We also report a brief review of what is known in general on the effects of changes in pH and copper concentration on rotifers at the population, species and community level, providing expectations for such effects on the rotifers of Lake Orta. Then, we conclude our review with a perspective on the potential use of rotifers hatched from the resting stages in the sediment of Lake Orta with the description of experiments that can be performed in the future in the framework of resurrection ecology, in order to understand the mechanisms of past and future changes in the environment.

Highlights • Very high rates of dissimilatory nitrate reduction to ammonium by Thioploca. • Non-steady state model predicts Thioploca survival on intracellular nitrate reservoir. • Ammonium release by Thioploca may be coupled to pelagic N loss by anammox. • Thioploca may contribute to anammox long after bottom water nitrate disappearance. • Model indicates that benthic foraminifera account for 90% of benthic N2 production. Abstract Benthic N cycling in the Peruvian oxygen minimum zone (OMZ) was investigated at ten stations along 12oS from the middle shelf (74 m) to the upper slope (1024 m) using in situ flux measurements, sediment biogeochemistry and modelling. Middle shelf sediments were covered by mats of the filamentous bacteria Thioploca spp. and contained a large ‘hidden’ pool of nitrate that was not detectable in the porewater. This was attributed to a biological nitrate reservoir stored within the bacteria to oxidize sulfide to sulfate during ‘dissimilatory nitrate reduction to ammonium’ (DNRA). The extremely high rates of DNRA on the shelf (15.6 mmol m-2 d-1 of N), determined using an empirical steady-state model, could easily supply all the ammonium requirements for anammox in the water column. The model further showed that denitrification by foraminifera may account for 90% of N2 production at the lower edge of the OMZ. At the time of sampling, dissolved oxygen was below detection limit down to 400 m and the water body overlying the shelf had stagnated, resulting in complete depletion of nitrate and nitrite. A decrease in the biological nitrate pool was observed on the shelf during fieldwork concomitant with a rise in porewater sulfide levels in surface sediments to 2 mM. Using a non-steady state model to simulate this natural anoxia experiment, these observations were shown to be consistent with Thioploca surviving on a dwindling intracellular nitrate reservoir to survive the stagnation period. The model shows that sediments hosting Thioploca are able to maintain high ammonium fluxes for many weeks following stagnation, potentially sustaining pelagic N loss by anammox. In contrast, sulfide emissions remain low, reducing the economic risk to the Peruvian fishery by toxic sulfide plume development.

Current de-oxygenation of the oceans is associated with severe habitat loss and distinct changes in the species composition of bentho-pelagic communities. We investigated the distributions of epibenthic megafauna across the Peruvian OMZ (11°S) at water depths ranging from ∼80 to 1000 m water depth using sea floor images. Likely controls of distributions were adressed by combining the abundances of major groups with geochemical parameters and sea-floor topography. In addition to bottom-water oxygen levels and organic-carbon availability, particular emphasis is laid on the effects of local hydrodynamics. Beside the occurrence of microbial mats at the shelf and upper slope, distinct zones of highly abundant megafauna, dominated by gastropods (900 ind. m−2), ophiuroids (140 ind. m−2), and pennatulaceans (20 ind. m−2), were observed at the lower boundary of the OMZ. Their distribution extended from 460 m water depth (O2 levels < 2 μM), where gastropods were abundant, to 680 m (O2 ∼6 μM) where epifaunal abundances declined sharply. Bottom water O2 represents a major factor that limits the ability of metazoans to invade deeply into the OMZ where they could have access to labile organic carbon. However, depending on their feeding mode, the distribution of organisms appeared to be related to local hydrodynamics caused by the energy dissipation of incipient internal M2 tides affecting the suspension, transport and deposition of food particles. This was particularly evident in certain sections of the investigated transect. At these potentially critical sites, energy dissipation of internal tides is associated with high bottom shear stress and high turbulences and coincides with elevated turbidity levels in the benthic boundary layer, increased Zr/Al-ratios, low sedimentation rates as well as a shift in the grain size towards coarser particles. In or near such areas, abundant suspension-feeding organisms, such as ophiuroids, pennatulaceans, and tunicates were present, whereas deposit-feeding gastropods were absent. The influence of local hydrodynamic conditions on the distribution of epibenthic organisms has been neglected in OMZ studies, although it has been considered in other settings.

The thermophilic ant genera Cataglyphis and Ocymyrmex share a variety of specialisations that enable them to engage in high-speed foraging at considerably higher temperatures than less heat-tolerant species. In the present account we test the hypothesis that thermophilic ants have longer legs than closely related species from more mesic habitats. By comparing large-sized, medium-sized, and small-sized species of Cataglyphis and Ocymyrmex with size-matched species of the closely related non-thermophilic genera Formica (Formicinae) and Messor (Myrmicinae), respectively, we show that the thermophilic species are equipped with considerably longer legs than their less heat-tolerant relatives. Hence phylogenetically, extreme long-leggedness has evolved at least twice in desert ants: in the Formicinae and the Myrmicinae. Functionally, this morphological trait is adaptive for a number of reasons. The long legs raise the body into cooler layers of air and enable higher running speeds, which increase convective cooling and reduce foraging time. These are important adaptations all the more as due to the low food density prevailing in desert habitats foraging Cataglyphis and Ocymyrmex ants have to cover large distances within their physically demanding foraging grounds.

Benthic nitrogen (N) cycling was investigated at six stations along a transect traversing the Peruvian oxygen minimum zone (OMZ) at 11 °S. An extensive dataset including porewater concentration profiles and in situ benthic fluxes of nitrate (NO3–), nitrite (NO2–) and ammonium (NH4+) was used to constrain a 1–D reaction–transport model designed to simulate and interpret the measured data at each station. Simulated rates of nitrification, denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA) by filamentous large sulfur bacteria (e.g. Beggiatoa and Thioploca) were highly variable throughout the OMZ yet clear trends were discernible. On the shelf and upper slope (80 – 260 m water depth) where extensive areas of bacterial mats were present, DNRA dominated total N turnover (less-than-or-equals, slant 2.9 mmol N m–2 d–1) and accounted for greater-or-equal, slanted 65 % of NO3– + NO2– uptake by the sediments from the bottom water. Nonetheless, these sediments did not represent a major sink for dissolved inorganic nitrogen (DIN = NO3– + NO2– + NH4+) since DNRA reduces NO3– and, potentially NO2–, to NH4+. Consequently, the shelf and upper slope sediments were recycling sites for DIN due to relatively low rates of denitrification and high rates of ammonium release from DNRA and ammonification of organic matter. This finding contrasts with the current opinion that sediments underlying OMZs are a strong sink for DIN. Only at greater water depths (300 – 1000 m) did the sediments become a net sink for DIN. Here, denitrification was the major process (less-than-or-equals, slant 2 mmol N m–2 d–1) and removed 55 – 73 % of NO3– and NO2– taken up by the sediments, with DNRA and anammox accounting for the remaining fraction. Anammox was of minor importance on the shelf and upper slope yet contributed up to 62 % to total N2 production at the 1000 m station. The results indicate that the partitioning of oxidized N (NO3–, NO2–) into DNRA or denitrification is a key factor determining the role of marine sediments as DIN sinks or recycling sites. Consequently, high measured benthic uptake rates of oxidized N within OMZs do not necessarily indicate a loss of fixed N from the marine environment.

For EU-Mediterranean olive groves (Olea europaea), mapped in CORINE, classes of olive farming intensities were derived from the outcome of a multi-temporal remote sensing vegetation dynamics analysis. The management intensity classes were developed in view of a differentiated accounting of olive groves when delineating High Nature Value Farmland areas (HNV) at pan-European level. The remote sensing input data used was the Green Vegetation Fraction (GVF), derived in 10-day intervals from a long-term time series of NOAA AVHRR data. The key physical parameters for the intensity assessment were obtained by parametrization of the observed annual growth cycle. These parameters represent two functional proportions in olive groves, a seasonally changing annual component and a permanent perennial vegetation component, which were interpreted to classify data in three olive farming intensity levels. 27% of the assessed EU-Mediterranean wide olive areas were found to be of very high intensity, 12% were classified as low intensity olive areas and 61% form an intermediate intensity class. Strong intensification was found in Spain, followed by Italy, Greece and Portugal. Most pronounced indications of management changes for the period 1990–2000 were observed for the Spanish provinces Jaen/Cordoba and the Italian province of Bari.

Due to the scarcity of information concerning the role that large foraminifera play in deep-sea carbon cycling, the response of a foraminiferal community (>250 pm) to a simulated phytodetritus sedimentation event was assessed over two weeks using sediment cores collected from a deep-fjord environment. Sediment cores were collected from similar to 700 in water depth in the Korsfjorden, western Norway, and incubated ex situ with 1 9 C-org m(2) of labile C-13-labeled Skeletonema costatum for 2, 7, and 14 days. We selectively picked (without prior staining) cytoplasm-containing foraminifera and found the foraminiferal community to be largely dominated (91%) by the deep-dwelling species Globobulimina turgida and Melonis barleeanum, as well as the shallow infaunal species 1 Hyalinea balthica. None of the >250 mu m, cytoplasm-containing fraction was involved in carbon uptake during the first 7 days. After 14 days, 3% of the foraminiferal samples possessed delta C-13 signatures indicative of carbon uptake, but the uptake was confined to the surface-living (0-2 cm) G. turgida. Foraminifera contributed 2.4% to faunal carbon uptake (foraminifera plus macrofauna) after 14 days, despite making up 24% of the combined biomass. Both the dominance of deep-infaunal species, such as G. turgida and M. barleeanum (68%), which are known to prefer degraded over more labile material, together with their large size, which often makes foraminifera respond slower to phytodetritus deposition than the more abundant, smaller-size foraminifera, are possible reasons for the retarded response observed. Overall, results from this investigation highlight that the response of large-size foraminifera to phytodetritus deposition is very slow. In addition, the results presented provide evidence that the foraminiferal response is most likely driven by differences in foraminiferal community composition and structure, with large, deep-infaunal species showing slower reactions to phytodetritus deposition compared to smaller foraminifera, metazoan meiofauna, and macrofauna.

The effect of methane seepage from sediments harbouring shallow gas hydrates on standing stocks and the distribution pattern of meiobenthic organisms, in particular Nematoda and Rotifera, was studied at about 800 m water depth at Hydrate Ridge, Cascadia subduction zone, off Oregon. The presence of shallow gas hydrates, buried only a few 10s of centimetres below the sediment surface, was indicated by extensive bacterial mats of chemosynthetic Beggiatoa sp. and clam fields of the bivalve mollusk Calyptogena spp. Mean abundances of meiobenthic organisms integrated over the upper 10 cm of the sediment were highest (1294 ind. 10 cm–2) at clam fields, closely followed by control sediments least affected by gas hydrates (1199 ind. 10 cm–2) and lowest in sediments covered with bacterial mats (762 ind. 10 cm–2). Average meiobenthic biomass was highest at the clam field site (262.2 µg C 10 cm–2), 210.4 µg C 10 cm–2 at the control site and very low in sediments covered with bacterial mats (61.4 µg C 10 cm–2). The dominant taxa of meiobenthic organisms at the investigated sites were nematodes and, unexpectedly, Rotifera that are almost unknown from the deep marine habitat. In terms of abundance, rotifera dominated the meiobenthic community in gas-hydrate-influenced sediments, while control sediments and deeper basins adjoined to Hydrate Ridge were dominated by nematodes. Nematodes were concentrated in the sediment surface at all sites, whereas rotifers were almost evenly distributed at all depths, with a slight preference for deeper sediment horizons. The horizontal as well as vertical distribution of nematodes and rotifers is likely to be determined by competition or predation, and by the high adaptive capability of rotifers to highly sulphidic and anoxic conditions. Estimates of meiobenthic carbon turnover in relation to the bulk organic carbon supply indicate that, in contrast to other meiobenthic communities in cold seep environments, the meiobenthos in the studied gas-hydrate-containing sediments do not benefit from the excess availability of organic carbon via the chemoautotrophic food web. This may be because, for most meiobenthic organisms (other than rotifers), tolerance mechanisms are overwhelmed by the deleterious environmental conditions of reduced oxygen availability and extremely high sulphide fluxes.

Context: Physiological gynecomastia is common and affects a large proportion of otherwise healthy adolescent boys. It is thought to be caused by an imbalance between estrogen and testosterone, although this is rarely evident in analyses of serum. Objective: This study aimed to describe the frequency of physiological gynecomastia and to determine possible etiological factors (eg, auxology and serum hormone levels) in a longitudinal setup. Design, Settings, and Participants: A prospective cohort study of 106 healthy Danish boys (5.8–16.4 years) participated in the longitudinal part of the COPENHAGEN Puberty Study. The boys were examined every 6 months during an 8-year follow-up. Median number of examinations was 10 (2–15). Main outcome measurements: Blood samples were analyzed for FSH, LH, testosterone, estradiol, SHBG, inhibin B, anti-Müllerian hormone, IGF-1, and IGF binding protein-3 by immunoassays. Auxological parameters, pubertal development, and the presence of gynecomastia were evaluated at each visit. Results: Fifty-two of 106 boys (49%) developed gynecomastia, of which 10 (19%) presented with intermittent gynecomastia. Boys with physiological gynecomastia reached peak height velocity at a significantly younger age than boys who did not develop gynecomastia (13.5 versus 13.9 years, P = .027), and they had significantly higher serum levels of IGF-1 (P = .000), estradiol (P = .013), free testosterone (P < .001), and FSH (P = .030) during pubertal transition. However, no differences in serum LH or in the estradiol to testosterone ratio were found. Conclusions: Gynecomastia is frequent in pubertal boys. Increased IGF-1 levels and pubertal growth appear to be associated, whereas changes in estrogen to testosterone ratio seem negligible.

Foraging desert ants navigate primarily by path integration. They continually update homing direction and distance by employing a celestial compass and an odometer. Here we address the question of whether information about travel distance is correctly used in the absence of directional information. By using linear channels that were partly covered to exclude celestial compass cues, we were able to test the distance component of the path-integration process while suppressing the directional information. Our results suggest that the path integrator cannot process the distance information accumulated by the odometer while ants are deprived of celestial compass information. Hence, during path integration directional cues are a prerequisite for the proper use of travel-distance information by ants.

Living (Rose Bengal stained) foraminifera in gas-hydrate-influenced sediments at the Cascadia convergent margin were investigated. Foraminiferal assemblages from the southern Hydrate Ridge and neighboring basins were compared in terms of abundances, vertical distribution, diversity, and species composition. At Hydrate Ridge, the presence of shallow gas hydrates and increased porewater sulfide concentrations was indicated by extensive bacterial mats of Beggiatoa sp. and clam beds of the bivalve mollusk Calyptogena sp., generating different biological zones. Living foraminifera were found in all biological zones, in sediment layers down to 5 cm. They showed highly variable densities within all zones. The average abundance of benthic foraminifera at Hydrate Ridge differs from neighboring basins. Average species diversities are comparable between biological zones, while the average number of species increases from bacterial mats to clam fields and surrounding sediments. Foraminifera can be characterized by 5 principal component communities which explain 97.3% of the variance of the live assemblages at the southern Hydrate Ridge and neighboring basins. At Hydrate Ridge, 2 foraminiferal zones can be distinguished: (1) an Uvigerina peregrina community which characterizes sediments covered with bacterial mats and clam fields; (2) a ?Spiroplectammina biformis community in the surrounding non-seep sediments. Foraminiferal assemblages in the neighboring Western and Eastern Basin differ from the Hydrate Ridge stations.

We estimated genetic and maternal variance components of larval life history characters in alpine populations of Rana temporaria (the common frog) using a full-sib/half-sib breeding design. We studied trait plasticity by raising tadpoles at 14 or 20°C in the laboratory. Larval period and metamorphic mass were greater at 14°C. Larval period did not differ between populations, but high elevation metamorphs were larger than low elevation metamorphs. Significant additive variation for larval period was detected in the low altitude population. No significant additive variation was detected for mass at metamorphosis (MM), which instead displayed significant maternal effects. Plasticity in metamorphic mass of froglets was greater in the high altitude population. The plastic response of larval period to temperature did not differ between the populations. Evolution of metamorphic mass is likely constrained by lack of additive genetic variation. In contrast, significant heritability for larval period suggests this trait may evolve in response to environmental change. These results differ from other studies on R. temporaria, suggesting that populations of this broadly distributed species present substantial geographic variation in the genetic architecture and plasticity of tadpole life history traits.

The effect of different ambient sulphide concentrations on the internal pH regime of Hediste (Nereis) diversicolor was studied under in vivo conditions using liquid membrane pH microelectrodes, a method which is new to marine sciences. As a case study, the hypothesis was tested whether organisms exposed to ambient sulphidic conditions are able to lower their internal pH which, in effect, would reduce sulphide influx into the animals and thus could represent an effective detoxification mechanism. It was shown that a significant lowering of the internal pH occurred within only 20 min after adding sulphide. This pH lowering appeared to be dependent on the external sulphide concentration of the ambient medium and showed a saturation beyond a threshold level of about 130 microM. It is discussed whether this sulphide-induced pH drop is an active regulatory mechanism and acts as an effective protection mechanism against sulphide during short-term exposures.

Effects of monsoon-induced enhanced depositional regimes of particulate organic carbon (POC) on regional variability and distribution patterns and size spectra of metazoan meiofauna, particularly of nematodes, were investigated at five sites 3158–4414 m deep in the Arabian Sea. The sampling sites were subjected to different flux rates of POC. Total meiofaunal abundance ranged from 109 to 320 ind./10 cm2. Nematodes were the numerically most abundant taxon, with a relative abundance of 82.5–88.7%, followed by copepods and ostracods. Mean individual nematode biomass ranged from 0.0272 to 0.1033 μgC, and Mean nematode population biomass varied between 0.0026 and 0.0133 mgC/10 cm2. Mean nematode lengths ranged from 614.2 to 832.6 μm. The length distributions of nematodes at the different sites were typically skewed with the distributions extending into the longer size classes. At the sites with higher POC deposition rates, nematodes displayed deeper distributions in the sediment column (47.4–58.5% of nematodes in the top 1 cm layer of the sediment) in contrast to very shallow distributions at a site of low POC flux (75.1% of nematodes in the top 1 cm of the sediment). Regional variability of nematode biomass, size and vertical distribution was related to monsoon-driven gradients of POC- and chlorophyll a (chl. a) flux rates and bacterial biomass i.e. bioavailable organic carbon. This was in contrast to nematode abundance which did not correlate significantly with any of these environmental parameters. The differential pattern between biomass and abundance, distribution might be related to POC-dependent alterations in the species composition of the nematode assemblages at the different sites. The hypothesis of increased meiobenthic stocks due to monsoon-induced enhanced sedimentation could not be confirmed compared to data from other less productive oceanic regions. Nematode abundance and biomass in the Arabian Sea were similar to values obtained from the abyssal temperate NE-Atlantic.

Interannual to decadal fluctuations in net precipitation and ice accumulation are examined over Greenland. It is shown that in western Greenland these fluctuations are correlated with the North Atlantic Oscillation. The analysis is based on two complementary data sources: A highly resolved net precipitation and accumulation history over 15 years derived form the reanalysis data of the European Centre for Medium-Range Weather Forecasts and a composite ice accumulation record representative for the western part of Central Greenland. It is suggested that western Greenland snow accumulation is a good proxy for the NAO index with the potential for the reconstruction of a long time series.

The discovery that foraminifera are able to use nitrate instead of oxygen as an electron acceptor for respiration has challenged our understanding of nitrogen cycling in the ocean. It was thought before that only prokaryotes and some fungi are able to denitrify. Rate estimates of foraminiferal denitrification have been very sparse and limited to specific regions in the oceans, not comparing stations along a transect of a certain region. Here, we present estimates of benthic foraminiferal denitrification rates from six stations at intermediate water depths in and below the Peruvian oxygen minimum zone (OMZ). Foraminiferal denitrification rates were calculated from abundance and assemblage composition of the total living fauna in both surface and subsurface sediments, as well as from individual species specific denitrification rates. A comparison with total benthic denitrification rates as inferred by biogeochemical models revealed that benthic foraminifera probably account for the total denitrification in shelf sediments between 80 and 250 m water depth. The estimations also imply that foraminifera are still important denitrifiers in the centre of the OMZ around 320 m (29–50% of the benthic denitrification), but play only a minor role at the lower OMZ boundary and below the OMZ between 465 and 700 m (2–6% of total benthic denitrification). Furthermore, foraminiferal denitrification has been compared to the total benthic nitrate loss measured during benthic chamber experiments. The estimated foraminiferal denitrification rates contribute 2 to 46% to the total nitrate loss across a depth transect from 80 to 700 m, respectively. Flux rate estimates range from 0.01 to 1.3 mmol m−2 d−1. Furthermore we show that the amount of nitrate stored in living benthic foraminifera (3 to 3955 μmol L−1) can be higher by three orders of magnitude as compared to the ambient pore waters in near-surface sediments sustaining an important nitrate reservoir in Peruvian OMZ sediments. The substantial contribution of foraminiferal nitrate respiration to total benthic nitrate loss at the Peruvian margin, which is one of the main nitrate sink regions in the world ocean, underpins the importance of the previously underestimated role of benthic foraminifera in global biogeochemical cycles.

Thermophilic desert ants—Cataglyphis, Ocymyrmex, and Melophorus species inhabiting the arid zones of the Palaearctic region, southern Africa and central Australia, respectively—are solitary foragers, which have been considered to lack any kind of chemical recruitment. Here we show that besides mainly employing the solitary mode of food retrieval Ocymyrmex robustior regularly exhibits group recruitment to food patches that cannot be exploited individually. Running at high speed to recruitment sites that may be more than 60 m apart from the nest a leading ant, the recruiter, is followed by a loose and often quite dispersed group of usually 2–7 recruits, which often overtake the leader, or may lose contact, fall back and return to the nest. As video recordings show the leader, while continually keeping her gaster in a downward position, intermittently touches the surface of the ground with the tip of the gaster most likely depositing a volatile pheromone signal. These recruitment events occur during the entire diurnal activity period of the Ocymyrmex foragers, that is, even at surface temperatures of more than 60 °C. They may provide promising experimental paradigms for studying the interplay of orientation by chemical signals and path integration as well as other visual guidance routines.

Background Members of the family Syngnathidae share a unique reproductive mode termed male pregnancy. Males carry eggs in specialised brooding structures for several weeks and release free-swimming offspring. Here we describe a systematic investigation of pre-release development in syngnathid fishes, reviewing available data for 17 species distributed across the family. This work is complemented by in-depth examinations of the straight-nosed pipefish Nerophis ophidion, the black-striped pipefish Syngnathus abaster, and the potbellied seahorse Hippocampus abdominalis. Results We propose a standardised classification of early syngnathid development that extends from the activation of the egg to the release of newborn. The classification consists of four developmental periods – early embryogenesis, eye development, snout formation, and juvenile – which are further divided into 11 stages. Stages are characterised by morphological traits that are easily visible in live and preserved specimens using incident-light microscopy. Conclusions Our classification is derived from examinations of species representing the full range of brooding-structure complexity found in the Syngnathidae, including tail-brooding as well as trunk-brooding species, which represent independent evolutionary lineages. We chose conspicuous common traits as diagnostic features of stages to allow for rapid and consistent staging of embryos and larvae across the entire family. In view of the growing interest in the biology of the Syngnathidae, we believe that the classification proposed here will prove useful for a wide range of studies on the unique reproductive biology of these male-brooding fish.

SUMMARY Foraging ants and bees use path-integration vectors and landmark cues for navigation. When in particular experimental paradigms the two types of information – vector-based and landmark-based information – are made to compete with each other, the insect may weight either source more heavily depending on the navigational context and the animal's motivational state. Here we studied the effects of a displaced nest mark on the homing performances of Cataglyphis ants. Foragers were trained to shuttle between the nest, which was marked by a black cylinder (the beacon), and an artificial feeder. Trained ants were captured at the feeder and transferred to a distant test field, where they experienced the nest mark at various positions relative to their home vector. When the beacon was positioned to one side of the point of release, the ants slightly drifted towards the beacon right at the start of their inbound run, but thereafter resumed their home-vector courses. When the nest mark appeared to one side further down the homing course, the ants set off in the home-vector direction, but then gradually drifted towards the beacon. The distance, at which this occurred,and the ants' drift from the home-vector course were very similar across test conditions. During the final search for the nest, landmark information dominated the ants' path integrator. The results clearly show that nest-mark memories are effective during the entire vector-based homeward course, but that they are either only partly activated or partly used unless the state of the ants' path integrator is close to zero.

When offered a permanent food source, central Australian desert ants, Melophorus bagoti , develop individually distinct, view-based foraging routes, which they retrace with amazing accuracy during each foraging trip. Using a particular channel setup connected to an artificial feeder, we trained M. bagoti ants to either two or three inward routes that led through different parts of their maze-like foraging grounds. Here, we show that ants are able to adopt multiple habitual paths in succession and that they preserve initially acquired route memories even after they have been trained to new routes. Individual ants differ in the consistency with which they run along habitual pathways. However, those ants that follow constant paths retain their route-specific memories for at least 5 days of suspended foraging, which suggests that even multiple route memories, once acquired, are preserved over the entire lifetime of a forager.

SummaryIn recent years, there has been an upsurge of interest and debate about whether social insects—central-place foragers [1] such as bees and ants—acquire and use cognitive maps, which enable the animal to steer novel courses between familiar sites [2–4]. Especially in honey bees, it has been claimed that these insects indeed possess such “general landscape memories” [5] and use them in a “map-like” way [6]. Here, we address this question in Australian desert ants, Melophorus bagoti, which forage within cluttered environments full of nearby and more distant landmarks. Within these environments, the ants establish landmark-based idiosyncratic routes from the nest to their feeding sites and select different one-way routes for their outbound and inbound journeys. Various types of displacement experiments show that inbound ants when hitting their inbound routes at any particular place immediately channel in and follow these routes until they reach the nest, but that they behave as though lost when hitting their habitual outbound routes. Hence, familiar landmarks are not decoupled from the context within which they have been acquired and are not knitted together in a more general and potentially map-like way. They instruct the ants when to do what rather than provide them with map-like information about their position in space.

Enantiocomplementary allylation of solid phase-bound aldehydes gives rise to a natural product-derived compound collection, including all stereoisomers of cryptocarya diacetate.

The spiro[5.5]ketal moiety forms the underlying structural skeleton of numerous biologically active natural products. Since simplified but characteristic spiroketals derived from the parent natural products retain biological activity, the spiro[5.5]ketal unit can be regarded as a biologically prevalidated framework for the development of natural product-derived compound collections. We report an enantioselective synthesis of spiro[5.5]ketals on solid support. The reaction sequence employs asymmetric boron enolate aldol reactions with the enolate bound to the polymer or in solution as the key enantiodifferentiating step. It proceeds in up to 12 steps on solid support, makes the desired spiroketals available in high overall yields and with high stereoselectivities and is amenable to structural variation of the products. The small spiroketal collection synthesized contains phosphatase inhibitors and compounds that modulate the formation of the tubulin cytoskeleton in human cancer cells without directly targeting microtubules. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Foraging desert ants, Cataglyphis fortis, monitor their position relative to the nest by path integration. They continually update the direction and distance to the nest by employing a celestial compass and an odometer. In the present account we addressed the question of how the precision of the ant's estimate of its homing distance depends on the distance travelled. We trained ants to forage at different distances in linear channels comprising a nest entrance and a feeder. For testing we caught ants at the feeder and released them in a parallel channel. The results show that ants tend to underestimate their distances travelled. This underestimation is the more pronounced, the larger the foraging distance gets. The quantitative relationship between training distance and the ant's estimate of this distance can be described by a logarithmic and an exponential model. The ant's odometric undershooting could be adaptive during natural foraging trips insofar as it leads the homing ant to concentrate the major part of its nest-search behaviour on the base of its individual foraging sector, i.e. on its familiar landmark corridor.

More than 50% of the Earth' s surface is sea floor below 3,000 m of water. Most of this major reservoir in the global carbon cycle and final repository for anthropogenic wastes is characterized by severe food limitation. Phytodetritus is the major food source for abyssal benthic communities, and a large fraction of the annual food load can arrive in pulses within a few days1, 2. Owing to logistical constraints, the available data concerning the fate of such a pulse are scattered3, 4 and often contradictory5, 6, 7, 8, 9, 10, hampering global carbon modelling and anthropogenic impact assessments. We quantified (over a period of 2.5 to 23 days) the response of an abyssal benthic community to a phytodetritus pulse, on the basis of 11 in situ experiments. Here we report that, in contrast to previous hypotheses5, 6, 7, 8, 9, 10, 11, the sediment community oxygen consumption doubled immediately, and that macrofauna were very important for initial carbon degradation. The retarded response of bacteria and Foraminifera, the restriction of microbial carbon degradation to the sediment surface, and the low total carbon turnover distinguish abyssal from continental-slope ‘deep-sea’ sediments.

Rotifers, one of the smallest metazoans, are only seldom found in marine environments. Surprisingly, we discovered high abundances of at least two new species of rotifers settling in anoxic and highly sulphidic sediments associated with shallow gas hydrates (GH) at the southern crest of Hydrate Ridge off Oregon, NE Pacific, in a water depth of about 780 m. At basins adjacent to Hydrate Ridge, 1,285–2,304 m deep, we found rotifers co-occurring with the sulphide-oxidising bacteria Thioploca sp.

The effect of methane released from decomposing surficial gas hydrates (SGH) on stand- ing stocks and activities of the small-sized benthic biota (SSBB; i.e. bacteria, fungi, protozoa, and meiobenthic organisms) was studied at about 790 m water depth, at the Hydrate Ridge, Cascadia sub- duction zone. Presence of SGH and elevated sulfide concentrations in the sediment were indicated by extensive bacterial mats of Beggiatoa sp. and clam fields of the bivalve mollusc Calyptogena sp. Verti- cal and horizontal distribution patterns of the SSBB biomass were derived from DNA and total adeny- late (TA) sediment assays. Potential bacterial exoenzymatic hydrolytic activity was measured using fluorescein-di-acetate (FDA) as substrate. Estimates of chemoautotrophic production of particulate or- ganic carbon (POC.) were determined by 14 CO2 uptake incubations. Inventories of chl a and pheopig- ments were determined as parameters of surface water primary produced POC input. Average SSBB bio- mass in clam field sediments integrated over the upper 10 cm (765.2 gC m -2 , SD 190.1) was 3.6 times higher than in the adjacent control sites (213 gC m -2 , SD 125). Average SSBB biomass in bacterial mat sediments, which were almost devoid of eukaryotic organisms > 31 µm, was 209 gC m -2 (SD 65). Sig- nificant correlations between FDA, DNA and plant pigments imply that productivity of the SSBB at SGH sites is only partially uncoupled from the primary production of the surface water. Areal estimates of autotrophic Corg production at control sites, bacterial mat sites and in clam field sites were 5.7, 59.7 and 190.0 mgC m -2 d -1 , respectively. Based on different models predicting vertical POC fluxes from surface water primary production and water depth, these autotrophic POC productions account for 5 to 17% (controls), 35 to 68% (bacterial mats), and 63 to 87% (clam fields) of the bulk POC (sum of allochthonous POC input through the water column and sedimentary autochthonous autotrophic POC production) pro- vided at the various sites. At SGH sites inventories of chl a and pheopigments, integrated over the upper 10 cm of the sediment, were half of that found at the control sites. This might be due to enhanced degra- dation of phytodetritally associated organic matter. The resulting low molecular weight organic carbon compounds might stimulate and fuel sulfate reduction, which is conducted in a microbial consortium with anaerobic methane consuming archaea. This syntrophic consortium might represent a prominent interface between gas hydrate derived carbon and allochthonous Corg flow. We infer that degradation kinetics of SGH is affected by, e.g., seasonally varying input of allochthonous organic matter.

Stand-replacing wildfire is an infrequent but important disturbance in southwestern pinyon-juniper woodlands. A typical successional cycle in these woodlands is approximately 300 years or more after a stand-replacing fire. Arthropods, especially ground-dwelling taxa, are one of the most abundant and diverse fauna in terrestrial ecosystems and are typically responsive to microhabitat change. Little is known regarding community responses of ground-dwelling arthropods to changes in woodland successional stages from early ecosystems dominated by grasses, herbaceous plants, and fire adapted shrubs to tree-dominated old-growth ecosystems. In 2007 and 2008, within Mesa Verde National Park, Colorado, we compared the community composition of ground-dwelling arthropods between old-growth pinyon-juniper stands that were 300–400 years old and early successional areas recovering from a stand-replacing fire in 2002. The 2002 fire eliminated the dominant woody vegetation, which was replaced by increased herbaceous vegetation and bare ground. The early successional arthropod community showed a significantly higher abundance in major arthropod taxonomic groups, except spiders, compared to old-growth woodland. Old-growth species richness was greater in late August–September, 2007 and greater in early successional habitats during April–July, 2008. Spatial variability of the habitat was much greater in the recently burned early successional plots than the old-growth late successional plots. The differences in habitat were strongly correlated with arthropod community composition, suggesting that ground-dwelling arthropods are very sensitive to habitat changes. Habitat affiliation was strong, with 83% (early succession ruderal) and 91% (old-growth woodland) of the species found primarily or exclusively in one habitat. Many habitat indicator species (defined as species found in significantly greater abundance in one habitat) were found in both burned and old-growth habitats. Several species were found to be strict specialists exclusive to only one of these habitats. Collectively, the results suggest that heightened concern over loss of old-growth woodlands is warranted, given the distinct nature of the ground-dwelling arthropod community in old-growth habitats.

The cover picture shows the stereoselective solid-phase synthesis of highly substituted spiroketal molecules. Asymmetric aldol reactions on a solid phase are the key steps involved in this synthetic route. Both resin-bound β-hydroxy aldehydes and boron enolates were employed for syn- and anti-aldol reactions, respectively. Out of this small collection of spiroacetals, some molecules showed activities against tubulin polymerization. The effect of two different spiroketals at a concentration of 5 μm on the tubulin cytoskeleton is shown in the picture (top right and bottom left). Furthermore, some spiroketals were found to be phosphatase inhibitors. Details are discussed in the article by H. Waldmann et al. on p. 4773 ff.

The paper describes the foraging ecology of the Australian desert ant, Melophorus bagoti, a thermophilic, diurnal scavenger with ground-nesting colonies. Overlapping foraging ranges, low foraging success rates, and intercolony aggression suggest intense competition for food between colonies. Daily foraging starts when soil surface temperatures approach 50°C. Workers search individually and collect predominantly dead insects. Occasionally, they consume plant secretions. Foraging activity peaks on mid-summer days. On cloudy days the onset of foraging is delayed, and the foraging activity is low. Ants do not forage on rainy days. Typically, workers start their above-ground activities with a few short exploration runs. On average, they perform one foraging run on the first day of their outdoor lives. With age they gradually increase foraging site fidelity and daily foraging effort. Individual foraging efficiency is low at the beginning but grows with experience. However, due to a high mortality rate and, hence, high forager turnover, average rates of foraging success for a colony remain rather low. The outdoor activity gradually decreases towards the end of summer and appears to stop completely during the winter months.