bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seabird distribution, abundance and diets in the eastern and central Aleutian Islands
Authors: JAHNCKE J. , COYLE K. O. , HUNT GEORGE L. 
Published: September 2005

AbstractWe examined the hypothesis that seabird distribution, abundance and diets differ among the eastern and central Aleutian Islands in response to distinct marine environments and energy pathways in each region. Research cruises were conducted in June 2001 and May–June 2002. We determined the distribution, abundance, diet and prey consumption of seabirds, and related these to zooplankton abundance and water masses that possess different physical properties. We found that distribution, abundance and diets of seabirds could be partitioned into two regions that correspond to marine environments determined by the extent of the Alaska Coastal Current along the eastern and central Aleutian Islands. Short‐tailed shearwaters (Puffinus tenuirostris) were the most abundant seabird in the coastal waters of the eastern Aleutian Islands, and northern fulmars (Fulmarus glacialis) were the most abundant seabird in the oceanic waters of the central Aleutian Islands. Seabird communities in the central and eastern Aleutian Islands were likely associated with different food webs. In the central Aleutian Islands, short‐tailed shearwaters and northern fulmars consumed shelf‐break species of euphausiids (Thyssanoesa longipes) and oceanic copepods (Neocalanus cristatus), respectively; in the eastern Aleutian Islands, both short‐tailed shearwaters and northern fulmars consumed shelf species of euphausiids (T. inermis). Carbon transport to seabirds was highest in Unimak and Akutan Passes where shearwaters removed large quantities of shelf euphausiids, followed by Samalga and Seguam Passes where northern fulmars removed large amounts of oceanic copepods.
Do patterns of Steller sea lion (Eumetopias jubatus) diet, population trend and cetacean occurrence reflect oceanographic domains from the Alaska Peninsula to the central Aleutian Islands?
Authors: SINCLAIR ELIZABETH H. , MOORE SUE E. , FRIDAY NANCY A. , ZEPPELIN TONYA K. , WAITE JANICE M. 
Published: September 2005

AbstractShipboard surveys were conducted along the Aleutian Islands in 2001 and 2002 to assess the influence of a suite of biophysical parameters on regional patterns in the distribution of cetaceans and Steller sea lions (SSL; Eumetopias jubatus). Distributions of four large whale species: fin (Balaenoptera physalus), humpback (Megaptera novaeangliae), minke (B. acutorostrata) and sperm (Physeter macrocephalus) aligned with proposed metapopulation breaks in diet and population trend of SSLs. Dall's porpoise (Phocoenoides dalli) and killer whales (Orcinus orca) were widely distributed throughout the study area, and killer whales were particularly prevalent along the north Aleutian Island coastlines between Unimak Pass and Samalga Pass. Biopsies determined that most killer whales (92%) were of the piscivorous (resident) ecotype as opposed to the mammal‐eating (transient) ecotype observed in 2002 only. Generalized additive models (GAMs) were used to explore relationships between these multispecies patterns in distribution, oceanographic variables (salinity, temperature, fluorescence and depth) and proximity to six Aleutian passes. The GAMs indicated the best‐fit models and most significant correlations as determined by the Akaike function and Cp‐statistics were: depth and proximity to the nearest measured pass for SSLs and all cetaceans, respectively; frequencies of herring and salmon in SSL diet with population trend; fluorescence in the top 50 m with occurrence of humpback, minke, and killer whales; and surface temperature with occurrence of humpback, killer, and sperm whales. Results of the GAM analyses suggest foci for future investigation of relationships between physical variables and interspecific patterns of marine mammal distribution.
Toward sustainable ecosystem services from the Aleutian Archipelago
Authors: SCHUMACHER J. D. , KRUSE GORDON H. 
Published: September 2005

AbstractThe new research reported in this special issue of Fisheries Oceanography expands our understanding of the Aleutian Archipelago ecosystem. Yet our knowledge remains very limited, while the use of this ecosystem for commercial activities, recreation and other purposes expands. Given this situation, how can we sustain the ecosystem services (food, fuel, fibers as well as spiritual, recreational, educational and other non‐material benefits to society) of this region? The region has a mixed history; healthy populations of many species exist, but so do species extinctions (e.g. Steller sea cow, Hydrodamalis gigas) and population depletions, including the sea otter (Enhydra lutris), Steller sea lion (Eumetopias jubatus), whiskered auklets (Aethia pygmaea), Pacific ocean perch (Sebastes alutus), and red king crabs (Paralithodes camtschaticus), associated with human impacts. The solution to our limited knowledge in this poorly studied region is increased funding for ecosystem research, including its responses to climate change and human impacts. Knowledge is not sufficient, however; a change in management approach is also needed. We emphasize the need to maintain a broader set of ecosystem services objectives rather than the traditional narrower focus on commercial fishery yields. To do so, we recommend the development of an integrated ecosystem services management plan for the Aleutian Islands. Such a plan requires that state and federal regulatory agencies coordinate with a broad stakeholder community involving sectors of commercial and recreational fishing, subsistence, conservation, oil and gas development, coastal development, shipping, tourism, and others.
Net heterotrophy in Faroe Islands clear‐water lakes: causes and consequences for bacterioplankton and phytoplankton
Authors: PÅLSSON CARINA , KRITZBERG EMMA S. , CHRISTOFFERSEN KIRSTEN , GRANÉLI WILHELM 
Published: September 2005

Summary1. Five oligotrophic clear‐water lakes on the Faroe Islands were studied during August 2000. Algal and bacterial production rates, community respiration, and CO2 saturation were determined. In addition, we examined the plankton community composition (phytoplankton and heterotrophic nanoflagellates) and measured the grazing pressure exerted by common mixotrophic species on bacteria.2. High respiration to primary production (6.6–33.2) and supersaturation of CO2 (830–2140 μatm) implied that the lakes were net heterotrophic and that the pelagic heterotrophic plankton were subsidised by allochthonous organic carbon. However, in spite of the apparent high level of net heterotrophy, primary production exceeded bacterial production and the food base for higher trophic levels appeared to be mainly autotrophic.3. We suggest that the observed net heterotrophy in these lakes was a result of the oligotrophic conditions and hence low primary production in combination with an input of allochthonous C with a relatively high availability.4. Mixotrophic phytoplankton (Cryptomonas spp., Dinobryon spp. and flagellates cf. Ochromonas spp.) constituted a large percentage of the plankton community (17–83%), possibly as a result of their capacity to exploit bacteria as a means of acquiring nutrients in these nutrient poor systems.
Continuous monitoring of phytoplankton dynamics in Lake Balaton (Hungary) using on‐line delayed fluorescence excitation spectroscopy
Authors: ISTVÁNOVICS VERA , HONTI MÁRK , OSZTOICS ANDRÁS , SHAFIK HESHAM M. , PADISÁK JUDIT , YACOBI YOSSEF , ECKERT WERNER 
Published: September 2005

Summary1. This study introduces delayed fluorescence (DF) excitation spectroscopy as an on‐line tool for in situ monitoring of the composition and biomass of various colour classes of phytoplankton when they are photosynthetically active (cyanobacteria, chlorophytes, chromophytes and cryptophytes). The DF data are validated by comparison with those from conventional methods (weekly microscopic counts and the measurement of chlorophyll concentration).2. The composition of phytoplankton as assessed by DF agreed reasonably well with the results from microscopic counts, particularly when differences in chlorophyll‐specific DF integrals of the various colour classes were taken into account.3. Integrals of DF spectra were converted into concentration of chlorophyll a using empirical factors derived from field data. The value of the conversion factor was nearly twice as high when the relative abundance of cyanobacteria was low (<15%) than when it was high. The converted DF‐chl time series agreed well with chlorophyll measurements particularly when blooms were developing. As the DF method is inherently free of the interference caused by pigment degradation products, the discrepancy between the two data sets increased during the collapse of blooms and when sediment resuspension was intense.4. Fourier spectrum analysis of the time series of DF‐chl indicated that samples must be taken, at a minimum, every 2–3 days to capture the dynamics of phytoplankton. As a consequence, the dynamics of various algal blooms, including their timing, duration and net growth rate, could be estimated with greater confidence than by using conventional methods alone.5. On‐line DF spectroscopy is an advanced technique for monitoring daily the biomass and composition of the photosynthetically active phytoplankton in aquatic environments, including turbid shallow lakes. At present, the detection limit is around 1 mg DF‐chl a m−3 in terms of total biomass but confidence in estimates of phytoplankton composition declines sharply below about 5 mg chl a m−3.6. On‐line DF spectroscopy represents a promising approach for monitoring phytoplankton. It will be useful in water management where it can act as an early‐warning system of declines in water quality. In basic ecological research it can supplement manual methods. While default calibration spectra may be acceptable for routine monitoring, we suggest a careful individual calibration of the DF spectrometer for basic research. The statistical methods developed here help to assess the adequacy of various calibration sets.
Hardening capacity in the Drosophila melanogaster species group is constrained by basal thermotolerance
Authors: KELLETT M. , HOFFMANN A. A. , MCKECHNIE S. W. 
Published: September 2005

Summary

To determine the relationship between basal thermotolerance and hardening capacity across related taxa, these traits were quantified for eight Drosophila species: D. melanogaster, D. simulans, D. sechellia and D. yakuba of the melanogaster subgroup and D. auraria, D. vulcana, D. serrata and D. birchii of the montium subgroup. The effects of pretreatment temperature and recovery time between pretreatment and heat shock on thermotolerance were also assessed.
For any given species, all elevated temperature pretreatments (31 °C, 33 °C and 35 °C) equally increased thermotolerance.
For any given species, increasing recovery time between pretreatment and heat shock increased thermotolerance, though this effect may be related to factors other than hardening.
Basal thermotolerance and absolute hardening capacity (pretreated thermotolerance minus basal thermotolerance) varied considerably among the species, and was not phylogenetically clustered.
Though unmodified and phylogenetically corrected correlations indicated a relationship between basal thermotolerance and absolute hardening capacity, this result was largely due to the presence of one species, the highly thermotolerant D. melanogaster.
Relative hardening capacity (absolute hardening capacity divided by basal thermotolerance) was fixed for all species at approximately 0·25.
Do faster starts increase the probability of evading predators?
Authors: WALKER J. A. , GHALAMBOR C. K. , GRISET O. L. , McKENNEY D. , REZNICK D. N. 
Published: September 2005

Summary

Nearly all fish evade predation strikes by rapidly accelerating out of the strike path, a behaviour called the fast‐start evasion response. The many studies investigating morphological, behavioural and ecological correlates of fast‐start performance assume that faster starts increase the probability of evasion.
We tested this faster‐start hypothesis by measuring the effect of acceleration ability on evasion outcome (success, failure) in Guppies (Poecilia reticulata) evading the strike of a natural predator, the Pike Cichlid (Crenicichla alta).
Four parameters affect evasion outcome: two parameters important to the predator–prey interaction but not to the faster‐start hypothesis – (1) the time required to reach the prey by the striking predator (measured by the initial distance between predator and prey and strike velocity), (2) the evasion path of the prey relative to the strike path of the predator; and two parameters relevant to the faster‐start hypothesis – (1) the ability of the prey to generate rapid tangential acceleration (measured by net distance travelled, maximum velocity, and maximum acceleration), and (2) the ability of the prey to rapidly rotate during the initial stage of the fast start.
On average, a one standard deviation increase in fast‐start performance increases the odds of surviving a predation strike 2·3‐fold. These results support the assumption that faster starts increase the probability of successfully evading a predation strike.
Traits of recalcitrant seeds in a semi‐deciduous tropical forest in Panamá: some ecological implications
Authors: DAWS M. I. , GARWOOD N. C. , PRITCHARD H. W. 
Published: September 2005

Summary

We used cross‐species and phylogenetic analyses to compare seed traits of 36 species with desiccation‐sensitive and 189 with desiccation‐tolerant seeds from a semi‐deciduous forest in Panamá.
When correcting for phylogenetic dependence between taxa, the desiccation‐sensitive seeds were significantly larger than desiccation‐tolerant seeds (3383 vs 283 mg) and typically shed during the wet (as opposed to dry) season. Both traits presumably reduce the rate of seed drying and hence the risk of desiccation‐induced mortality for the desiccation‐sensitive species.
Growing‐house germination trials in simulated understorey and canopy gap environments revealed that the desiccation‐sensitive species germinated most rapidly. Additionally, on a proportion basis, the desiccation‐sensitive seeds allocated significantly less resources to seed physical defences (endocarp and/or testa) which may partially facilitate rapid germination. Both relationships were significant when correcting for phylogenetic dependence and seed mass.
Our results suggest that, for large‐seeded species which will dry slowly, desiccation sensitivity may be advantageous. Rapid germination may reduce the duration of seed exposure to predation, and the low investment in physical defence means that, per unit mass, desiccation‐sensitive seeds are a more efficient use of resources in seed provisioning.
Carotenoid ornamentation of adult male Common Redpolls predicts probability of dying in a salmonellosis outbreak
Authors: VAN OORT H. , DAWSON R. D. 
Published: September 2005

Summary

Conditional handicap models of sexual selection predict that ornamentation should be positively associated with an individual's ability to withstand challenges to their health.
We assessed whether levels of carotenoid ornamentation were related to the probability of adult male Common Redpolls, Carduelis flammea, dying in a salmonellosis epidemic by comparing the ornamentation of surviving adult male redpolls to those found dead. Hosts suffering from salmonellosis shed bacteria in faeces, and new individuals are typically infected when they ingest faeces‐contaminated food.
The proportion of adult males in the sample of dead birds was significantly higher than in the sample of living birds.
Among adult males, probability of survival was significantly predicted by the expression of their carotenoid signals: brightly ornamented adult males were more likely to die in the epidemic.
A probable hypothesis for these results is that if carotenoid ornamentation in redpolls functions as a status badge of dominance, bright males would have had priority access to highly preferred, and contaminated, food patches.
Morphology, performance and fighting capacity in male lizards, Gallotia galloti
Authors: HUYGHE K. , VANHOOYDONCK B. , SCHEERS H. , MOLINA‐BORJA M. , VAN DAMME R. 
Published: September 2005

Summary

Morphological characteristics (snout–vent length, badge area, mass, limb and head measures) and whole‐animal performance capacities (sprint speed, acceleration capacity, stamina and bite force) were measured in male lizards, Gallotia galloti. These males were also tested in paired staged contests to assess relative fighting capacity and to link these results to morphology and performance.
A multivariate analysis of the four performance features revealed a clear difference between the physiological capacities of winners vs losers, with bite force being the most important predictor of the outcome of fights.
The finding that bite performance is linked to dominance fits in with the high sexual dimorphism in head size in this species, as head size is a predictor of bite force performance.
Winners of contests also tended to have larger total areas of blue patches on their sides, suggesting that these badges convey information on the social status of the males. However, since no correlation was found between bite force and badge size, the patches seem to contain information on a component of fighting capacity other than bite force.
Nitric oxide (NO) as an intermediate in the cryptogein‐induced hypersensitive response – a critical re‐evaluation
Authors: PLANCHET ELISABETH , SONODA MASATOSHI , ZEIER JÜRGEN , KAISER WERNER M. 
Published: September 2005

ABSTRACTA hypersensitive response (HR) was induced in tobacco leaves and cell suspensions by the fungal elicitor cryptogein, and NO production was followed by chemiluminescence and occasionally by diaminofluorescein (DAF)‐fluorescence. Results from both methods were at least partly consistent, but kinetics was different. NO emission was not induced by cryptogein in leaves, whereas in cell suspensions some weak NO emission was observed, which was nitrate reductase (NR)‐dependent, but not required for cell death. Nitric oxide synthase (NOS) inhibitors did not prevent cell death, but PR‐1 expression was weakened. In conclusion, neither NR nor NOS appear obligatory for the cryptogein‐induced HR. However, a role for NO was still suggested by the fact that the NO scavenger cPTIO prevented the HR. Unexpectedly, cPTI, the reaction product of cPTIO and NO, also impaired the HR but without scavenging NO. Thus, prevention of the HR by cPTIO is not necessarily indicative for a role of NO. Further, even a 100‐fold NO overproduction (over wild type) by a nitrite reductase‐deficient mutant did not interfere with the cryptogein‐induced HR. Accordingly, the role of NO in the HR should be reconsidered.
Evidence from Amazonian forests is consistent with isohydric control of leaf water potential
Authors: FISHER ROSIE A. , WILLIAMS MATHEW , DO VALE RAQUEL LOBO , DA COSTA ANTONIO LOLA , MEIR PATRICK 
Published: September 2005

ABSTRACTClimate modelling studies predict that the rain forests of the Eastern Amazon basin are likely to experience reductions in rainfall of up to 50% over the next 50–100 years. Efforts to predict the effects of changing climate, especially drought stress, on forest gas exchange are currently limited by uncertainty about the mechanism that controls stomatal closure in response to low soil moisture. At a through‐fall exclusion experiment in Eastern Amazonia where water was experimentally excluded from the soil, we tested the hypothesis that plants are isohydric, that is, when water is scarce, the stomata act to prevent leaf water potential from dropping below a critical threshold level. We made diurnal measurements of leaf water potential (Ψl), stomatal conductance (gs), sap flow and stem water potential (Ψstem) in the wet and dry seasons. We compared the data with the predictions of the soil–plant–atmosphere (SPA) model, which embeds the isohydric hypothesis within its stomatal conductance algorithm. The model inputs for meteorology, leaf area index (LAI), soil water potential and soil‐to‐leaf hydraulic resistance (R) were altered between seasons in accordance with measured values. No optimization parameters were used to adjust the model. This ‘mechanistic’ model of stomatal function was able to explain the individual tree‐level seasonal changes in water relations (r2 = 0.85, 0.90 and 0.58 for Ψl, sap flow and gs, respectively). The model indicated that the measured increase in R was the dominant cause of restricted water use during the dry season, resulting in a modelled restriction of sap flow four times greater than that caused by reduced soil water potential. Higher resistance during the dry season resulted from an increase in below‐ground resistance (including root and soil‐to‐root resistance) to water flow.
Activation of Natural Killer‐Like YT‐INDY Cells by Oligodeoxynucleotides and Binding by Homologous Pattern Recognition Proteins
Authors: Kaur H. , Jaso‐Friedmann L. , Leary J. H. , Praveen K. , Brahmi Z. , Evans D. L. 
Published: September 2005

AbstractThe present study was designed to examine the binding and signalling effects of single base and CpG dinucleotide phosphodiester (Po) oligodeoxynucleotides (ODN) on the human natural killer (NK)‐like cell line (YT‐INDY). Single base Po ODN composed of 20‐mers of guanosine (dG20), adenosine (dA20), cytosine (dC20) or thymidine (dT20) as well as ‘conventional’ Po CpG ODN were examined for their ability to bind and activate YT‐INDY cells. Binding by dG20 and CpG ODN to YT‐INDY cells was saturable and specific. dG20 binding was competitively inhibited by homologous dG20 and heterologous CpG ODN but not by dC20 and dA20. Two different YT‐INDY membrane proteins (18 and 29 kDa) were identified by ligand (Southwestern) blotting with biotinylated dG20 and CpG. The specificity of the ODN‐binding protein(s) was further confirmed by ODN depletion experiments using a teleost recombinant protein orthologue [nonspecific cytotoxic cells (NCC) cationic antimicrobial protein‐1 (ncamp‐1)] known to bind CpG and dG20. Cell proliferation and activation studies showed that dG20 and CpG treatment of YT‐INDY cells induced cellular DNA synthesis (i.e. G1 to S‐phase conversion). This signalling function was accompanied in dG20‐treated cells by proliferation 10 h posttreatment. Both dG20 and CpG ODN binding induced a calcium flux in YT‐INDY cells within seconds of treatment. These experiments demonstrated that Po single base dG20 and CpG ODN bind to a (potential) new class of cell‐surface proteins that mediate the activation of YT‐INDY cells.
Burial‐exhumation history of the central Apennines (Italy), from the foreland to the chain building: thermochronological and geological data
Authors: Rusciadelli G. , Viandante M.G. , Calamita F. , Cook A.C. 
Published: September 2005

AbstractA clear correlation between regional unconformities and related exhumation events was documented by thermochronological and geological data in the central Apennines. This approach allowed: (i) two major exhumation episodes to be identified, corresponding to turning points in the long‐term burial history, from rifting to convergent margin development, and (ii) a quantification of the amount of section removed during the two exhumation events. The first exhumation event was connected with the foreland buckling process associated with the coupling between the Alpine–Apennines system, the Dinarides chain and their common foreland. During the Neogene a thrust‐system development, the superposition of an allochthonous unit is envisaged to explain the second palaeoheating event. The dismantling of this additional load in central Apennines has been related to the formation of the Middle Pliocene Unconformity, during the development of the Pliocene–Quaternary frontal thrust of the Apennine Chain.