Temperature and metabolic rate in sedentary fish from the Antarctic,North Sea and Indo-West Pacific Ocean

Resting metabolic rate was measured in demersal stages of the teleostNotothenia neglecta Nybelin from the South Orkney Islands, Antarctica, from 1985 to 1987. The relationship between and body mass (Mb) conformed to the general relationship , wherea is a proportionality constant andb is the scaling exponent. (mg O₂ h^–1) was found to scale toMb ^{(0.82±0.011)} in the summer (November to April, 1.6 to 1 850 g,n=56) and toMb ^{(0.76±0.013)} in the winter (May to October, 0.9 to 1 850 g,n=57) (values ofb are means ± SD). Although the scaling exponents were significantly different (P<0.01), was similar in the juvenile stages of summer- and winter-caught fish matched for body mass. The effects of activity on oxygen consumption was studied using a Brett respirometer. Adult stages had a factorial aerobic scope for activity of 5.7, which is similar to that reported for demersal fish from temperate latitudes. The effects of temperature on resting metabolism was investigated in fish with similar sedentary lifestyles from the North Sea (Agonus cataphractus andMyoxocephalus scorpius) and the Indo-West Pacific (Paracirrhites forsteri, P. arcatus, Neocirrhites armatus andExallias brevis). Extrapolated values of for the tropical species approached zero at 5 to 10°C. For a standard 50 g fish, for the tropical species at 25°C was in the range 3.4 to 4.4 mg O₂ h^–1, compared with 1.3 mg O₂ h^–1 forNotothenia neglecta at its acclimation temperature. Thus, the maximum metabolic rate of sedentary tropical species at 24°C is likely to be 2 to 4 times higher than inN. neglecta at 0°C. This suggests that the energy available for sustained activity is significantly lower in cold- than in warm-water fish.     

Oxygen consumption inNeomysis americana (Crustacea: Mysidacea), and the effects of naphthalene exposure

Oxygen uptake ( ) of individual mysids was measured in a novel continuous flow respirometer for 24-h periods, and in a sealed chamber respirometer for several hours. Mysids were acclimated 30–100d under conditions which allowed complete life-cycle cultivation. was normalized for mysid size using an unconventional linear regression: log ( ) vs log (body water). Compared to the conventional regression, log ( ) vs log (body mass), the new approach showed two advantages: significantly greater coefficient of determination,r ², and removal of differences in between sexes. Minimum rates of oxygen uptake measured in the continuous flow respirometer were lower than sealed chamber measurements, and may more accurately reflect standard metabolic rate. Hourly data also showed a daily cycle when adjusted to represent a standard size mysid. Exposure to ca 1.1 mg l^-1 naphthalene increased and the range of spontaneous shown by the mysids; exposure to ca 0.1 mgl^-1 naphthalene depressed the range of . Both exposures caused aberrations in the daily cycle.     

Oxygen and carbon dioxide exchange in the polychaete Nereis virens: influence of ventilation activity and starvation

The influence of ventilation activity and starvation on O₂ uptake and CO₂ production in the polychaete Nereis virens Sars was investigated during September 1986 using worms collected on intertidal flats outside the Nærå Strand estuary, Denmark. The activity level, measured as ventilation rate, , was linearly related to active O₂ uptake, , for worms inhabiting artificial burrows (i.e. tubes) in the laboratory. at 16°C was two and four times the extrapolated standard O₂ uptake ( =0) when was 100 and 500 ml g^-1 h^-1, respectively. The use of tubes had no significant effect on N. viren's temporal ventilation pattern, D_v, compared to natural burrows in sediment. The ventilation rate, , however, was 2 to 3 times higher in tubes than in burrows. Starvation affected both ventilation and gas exchange. increased slightly during the first six days remaining constant thereafter. D_v, on the othe hand, decreased during the first six days followed by a gradual increase to Day 20. The observed decrease in D_v (%) from Day 0 to 1 was attributed to insufficient acclimation of the worms. The time integrated ventilation rate, × D_v, increased gradually throughout the 20 d starvation period. and declined rapidly during the first days of starvation. After 10 d the gas exchange reached steady levels at about 50% of the initial rate. The observed decrease in metabolic rate during starvation was explained by a rapid initial reduction in specific dynamic action (SDA) followed by a gradual exhaustion of readily available metabolic reserves, e.g. glycogen and lipids.     

Ecophysiology of the benthic amphipod Monoporeia affinis in an open-sea area of the northern Baltic Sea: seasonal variations in oxygen consumption and ammonia excretion

Seasonal variations in the oxygen uptake rate ( ) and ammonia excretion rate ( ) of the benthic deposit-feeding amphipod Monoporeia affinis vere studied in an open-sea population of the northern Baltic Sea during three consecutive years (1991 to 1993). In the early summer an increase in the weightspecific by 22% (standard 1-mg individual) was registered; an even more striking change was noted in the , which showed an increase in the early summer of ca. six times the extremely low winter/spring valnes. The metabolic changes observed could not be attributed to temperature, which remained at steadystate throughout the year, nor could seasonal variations in the biochemical composition of the amphipods explain the results. Therefor, it is evident that quality-food abundance following the sedimentation of the spring phytoplankton bloom induces the observed early-summer elevations in and . In turn, the marked decrease in the towards autumn reflects the gradual depletion of quality-food in the benthic environment. Atomic O: N ratios indicated that at the sampling location, M. affinis uses lipid almost exclusively for metabolic energy throughout the year, except in early summer when the use of lipid and protein was observed to be almost equal. Results also indicated a time-lag between sedimentation of the phytoplankton bloom and metabolic response in the amphipod population.     

Physiological responses of Mytilus edulis and Cardium edule to aerial exposure

Physiological responses of two bivalves (Mytilus edulis L. and Cardium edule L.) to intertidal conditions were studied. Specimens were collected from S. W. England in autumn/winter, 1980, and acclimatized to either intertidal or subtidal regimes before measurement of rates of heat dissipation and oxygen uptake during 5 h of air exposure, and rates of , particle clearance, ammonia excretion, and food-absorption efficiency during 7 h of reimmersion. Subtidal individuals were either intermittently or continuously fed in order to distinguish the effects of periodic food supply from the effects of air exposure. Specimens of M. edulis had low aerial rates of (14 to 20% of aquatic rate), and was greater than the energy equivalent of , indicating that they were largely anaerobic. In contrast, C. edule air-gaped and had higher aerial rates of and (50 to 75% of aquatic rate). There were behavioural and metabolic differences in the responses of intertidally and subtidally acclimatized mussels and cockles to air exposure. Intertidal individuals of both species were more quiescent, had lower aerial rates of and , and showed a conditioned response at the expected time of reimmersion. The reduction in aerial rate of was an energy-saving mechanism and the payment of the oxygen-debt within 2 h of reimmersion represented a significant cost. The heat increment associated with feeding and digestion was estimated as 15 to 17% of the oxygen uptake by M. edulis during all stages of recovery. M. edulis adapted to the intertidal regime by reducing its time-averaged aerial and aquatic rates of ammonia excretion. In contrast, C. edule maintained a high aerial and aquatic rate of ammonia excretion. The clearance rates of M. edulis recovered rapidly (0.5 to 1.5 h) following reimmersion, whereas those of C. edule recovered more slowly, particularly for the subtidal individuals following acute exposure (>4 h). There was no evidence of increased clearance rate or absorption efficiency by intertidal individuals to compensate for the loss of feeding time. Intertidally acclimatized individuals of M. edulis and C. edule had more energy available for growth (scope for growth) integrated over a 12 h period and higher growth efficiencies than subtidal individuals subjected to acute air exposure and intermittent feeding regimes. This was the result of reduced aerial and aquatic rates of energy expenditure, a relatively small cost in terms of the payment of oxygen-debt and a rapid recovery of clearance rate following reimmersion.     

Waves and turbulence in katabatic winds

The measurements taken during the Vertical Transport and Mixing Experiment (VTMX, October, 2000) on a northeastern slope of Salt Lake Valley, Utah, were used to calculate the statistics of velocity fluctuations in a katabatic gravity current in the absence of synoptic forcing. The data from ultrasonic anemometer-thermometers placed at elevations 4.5 and 13.9 m were used. The contributions of small-scale turbulence and waves were isolated by applying a high-pass digital (Elliptical) filter, whereupon the filtered quantities were identified as small-scale turbulence and the rest as internal gravity waves. Internal waves were found to play a role not only at canonical large gradient Richardson numbers $(\overline{\hbox {Ri}_\mathrm{g} } >1)$ , but sometimes at smaller values $(0.1 < \overline{\hbox {Ri}_\mathrm{g}}<1)$ , in contrast to typical observations in flat-terrain stable boundary layers. This may be attributed, at least partly, to (critical) internal waves on the slope, identified by Princevac et al. [1], which degenerate into turbulence and help maintain an active internal wave field. The applicability of both Monin-Obukhov (MO) similarity theory and local scaling to filtered and unfiltered data was tested by analyzing rms velocity fluctuations as a function of the stability parameter z/L, where L is the Obukhov length and z the height above the ground. For weaker stabilities, $\hbox {z/L}<1$ , the MO similarity and local scaling were valid for both filtered and unfiltered data. Conversely, when $\hbox {z/L}>1$ , the use of both scaling types is questionable, although filtered data showed a tendency to follow local scaling. A relationship between z/L and $\overline{\hbox {Ri}_\mathrm{g} }$ was identified. Eddy diffusivities of momentum $\hbox {K}_\mathrm{M}$ and heat $\hbox {K}_\mathrm{H}$ were dependent on wave activities, notably when $\overline{\hbox {Ri}_\mathrm{g} } > 1$ . The ratio $\hbox {K}_{\mathrm{H}}/\hbox {K}_{\mathrm{M}}$ dropped well below unity at high $\overline{\hbox {Ri}_\mathrm{g} }$ , in consonance with previous laboratory stratified shear layer measurements as well as other field observations.     

Growth,condition and specific dynamic action in the mussel Mytilus edulis recovering from starvation

Juvenile Mytilus edulis were grown individually in plastic racks in a tidal salt marsh for 72 d in 1984, starved in the laboratory for 130 d, and then fed the alga Isochrysis galbana daily for 64 d. Oxygen consumption was measured at various times during the course of starvation and recovery. The effects of both size (tissue dry weight) and condition (tissue size relative to shell size) on the rate of oxygen consumption during the course of starvation and recovery were analyzed by multiple regression. Weight-specific preprandial rate was inversely correlated with both size and condition. Weight-specific active rate (measured shortly after feeding) was correlated with size but not condition. Relative Scope for Activity was inversely correlated with size and positively correlated with condition. Relative Specific Dynamic Action (RSDA; the integrated physiological and mechanical response to a meal) was initially correlated negatively with size and subsequently positively with condition. Glycogen content was shown to be positively correlated with condition in mussels before starvation and during recovery. During recovery, experimental mussels returned to 90% of their estimated dry weight prior to starvation, and from 53% after starvation. At weekly intervals during recovery, oxygen consumption was measured following a meal until it returned to the preprandial rate. Both pre- and postprandial volumes (l at STP) of oxygen consumed per hour ( O _2pre and O _2post , respectively) increased significantly during recovery. The postprandial rise in oxygen consumption increased significantly from 15% to 23% of O _2pre . At the end of the recovery period, RSDA [( O _2post – O _2pre )/ O _2pre ] was independent of final dry weight, but was significantly correlated with percent dry weight recovered (r ²=0.44; df=10; P<0.02). The increase in RSDA may reflect increased utilization of food and its conversion to soma during recovery from starvation, as distinct from mechanical energy expenditure (feeding activity) following a meal.     

Abundance and biomass of macrobenthos in the vicinity of Carson Submarine Canyon,northwest Atlantic Ocean

The abundance, biomass and mean weight of macrofauna in the Carson Canyon region (Lat. 45°30N, Long. 48°40W) of the Grand Banks were estimated from 40 quantitative infaunal samples taken at 15 stations in June 1980. In contrast to other areas, there were no significant differences in these values between samples taken in and outside of the canyon. Abundance ( = 716 individuals m^-2), biomass ( = 10.9 gm^-2), and mean weight ( = 0.03 g individual^-1) displayed no consistent relationship with depth, but stations grouped according to sediment type had differing dominant taxa. Biomass and abundance at the edge of the Grand Banks are unexpectedly low. Larger animals, including fishes, that forage there must depend more on pelagic than on benthic food sources.     

Comparative studies on the metabolism of shallow-water and deep-sea marine fishes. IV. Patterns of aerobic metabolism in the mesopelagic deep-sea fangtooth fish Anoplogaster cornuta

Measurements have been made of oxygen consumption rates O₂ of 10 specimens of the mesopelagic deep-sea fangtooth fish Anoplogaster cornuta. Determinations were made at 1 atm pressure, at temperatures of 3°, 7°, and 10°C, at dissolved oxygen concentrations ranging from near saturation to zero, with the fish swimming at low, controlled speeds. Weight-specific O₂ were uniformly low. They showed Q₁₀'s of 2.5 and 1.3, respectively, in the temperature ranges 3° to 7°C, and 7° to 10°C, at dissolved oxygen concentrations above 2 ml (standard temperature and presusure, STP)/1. Measurable O₂ continued in these fish at dissolved oxygen concentrations down to the lowest levels detectable with our instruments. At 7°C the average critical oxygen tension (P _c ) for the entire group was near 35 mm Hg. However, there is a statistically significant positive slope to the regression line relating O₂ to P _c for individual fish. The physiological and ecological significance of these results is discussed, particularly with reference to thermal effects and to the basis for survival by A. cornuta in the oxygen minimum layers of the eastern Pacific Ocean.     

Comparative studies on the metabolism of shallow-water and deep-sea marine fishes. V. Effects of temperature and hydrostatic pressure on oxygen consumption in the mesopelagic zoarcid Melanostigma pammelas

Measurements have been made of routine oxygen consumption rates ( ) of the mesopelagic deep-sea zoarcid fish Melanostigma pammelas. Determinations were made over ecologically relevant ranges of 3 variables; temperature (3° to 10°C), hydrostatic pressure (1 to 170 atm), and oxygen partial pressure (1 to 160 mm Hg). Weight-specific s were uniformly low. Of the 3 test variables, only temperature had significant metabolic effects within the ranges studied. Q₁₀'s were 6.75 between 3° and 5°C. 1.47 between 5° and 7°C, and 17.4 between 7° and 10°C. These Q₁₀'s were constant over the hydrostatic pressure range studied. Between 3° and 7°C the fish regulated their rates of oxygen consumption down to PO₂'s comparable to those occurring in their natural environments (6 to 12 mm Hg). The showed no capacity to tolerate anoxic conditions. The physiological and ecological significance of these results is discussed, particularly with reference to thermal effects and to the basis of survival of this fish in the oxygen minimum layers of the eastern Pacific Ocean. Since it is possible to maintain M. pammelas in the laboratory for extended periods of time (over 12 months) it could serve as the basis for many interesting studies of deep-sea fish biology.     

Sperm competition in the damselfly Enallagma hageni Walsh (Odonata: Coenagrionidae): benefits of multiple mating to males and females

Summary Sperm competition was investigated in the non-territorial damselfly, Enallagma hageni. Using irradiated (sterile) male techniques, the last male to mate was found to fertilize up to 95% of the eggs of the first clutch laid after mating. Dissection of females collected before, during, and after copula showed that a male removes a maximum of 87% of the sperm by volume of a previous mate. These data verify an earlier estimate of lifetime reproductive success in this species which was based on mating success, and suggest that indirect dissection methods offer minimum estimates of sperm precedence. Male E. hageni have ample opportunity to benefit from sperm precedence, since at least 10% of the receptive females encountered had already mated once that day, but still contained complete or partial clutches of eggs. Female E. hageni benefit directly from high sperm precedence because it allows them to exchange matings for guarding service by males during oviposition bouts under water.     

Flow rate and particle concentration within the house of the pelagic tunicate Oikopleura vanhoeffeni

The food-concentrating filter within the house of Oikopleura vanhoeffeni Lohmann consists of three layers, upper and lower fine-mesh layers and an intermediate coarse-mesh layer. The filter is a natural analogue of man-made tangential, or cross-flow, filters that are used to concentrate fine particulate and colloidal material by the exclusion of water. Flow analysis using video microscopy of O. vanhoeffeni, collected in 1989 and 1990 at Logy Bay, insular Newfoundland, indicates concentration of particles of 74 to 1089 times that of ambient seawater ( ,n=23), for individuals 1.8 to 5.4 mm long. The smallest individuals had the highest concentration factors. Flow through the house is predominately affected by viscous forces and values of Reynolds numbers are 1. Flow rates through the house of O. vanhoeffeni indicate a maximum filtration capacity of ca. 1.4 to 26 liters d^-1 and clearance rates (assuming ca. 50% of the time is spent not actively pumping) of 0.7 to 13 liters d^-1, depending on body size. The estimated thickness of the boundary layer around individual fibers of the food-concentrating filter is 0.08 m, which is less than the pore width. The estimated concentration factors suggest that colloidal and fine particulate material may aggregate into larger particles within the food-concentrating filter and food tube during feeding.     

Morphological and genetic variation in Japanese populations of the anemonefish Amphiprion clarkii

Geographic populations of the anemonefish Amphiprion clarkii (Bennett) from 6 widely separated locations off the coast of southern Japan are morphologically different, exhibiting (1) latitudinal clinal patterns in color pattern and meristics and (2) degrees of genetic differentiation. Electrophoretic examination of 7 polymorphic loci (95% level) among 6 populations collected between July 1979 and January 1980 revealed an average genetic distance value of 0.008. Significance was demonstrated for 39 out of 105 (37%) tests of heterogeneity. Averaged over the 6 populations, the percentage of polymorphic loci ( _0.95) was 24.6% and the proportion of heterozygous loci per individual ( ) was 0.0613. The results indicate that genetic clines are absent and suggest that the morphological variation may not be genetic. Relative isolation of genetic populations may be maintained by (1) localized larval dispersal resulting from a relatively short larval stage, and (2) current gyres tending to trap larvae, increasing the return of juveniles to their adult coastal habitat. Morphological clines may be due to clines in ecological parameters related to latitude.Contribution No. 39 of the Tatsuo Tanaka Memorial Biological Station     

Quantitative estimates of the meiofauna from the deep sea off North Carolina,USA

In 1974 the authors collected, sorted and enumerated meiofauna from 400, 800 and 4000 m off North Carolina, USA. Samples were replicated respectively with 4 boxcores and 21 subsamples, 2 boxcores and 7 subsamples and 2 boxcores and 8 subsamples. Total meiofaunal numbers were highest in fine silt sediment at 800 m ( =891.9 10 cm_–2) and lowest in very fine silt at 4000 m ( =73.5 10 cm_–2). Fine sand at 400 m yielded a mean of 442.4 10 cm^–2. At all depths, most fauna were located in the upper 3 cm of sediment ( depth distribution=2.2 cm), and typically only nematodes and foraminiferans were found below 4 cm. Total community abundances significantly differed with depth; however, there were no differences among replicate boxcores at particular depths. Since most (85.7%) of the variance was associated with subsamples from a boxcore, it appears that meiofauna densities are homomeneous within large areas at particular depths, and that patchiness is a smallscale phenomenon at the level of the 10 cm² subsampler. Comparisons of sorting efficiencies of live and preserved samples indicated that to accurately enumerate formainiferans, samples must first be fixed and stained, while turbellarians and oligochaetes must be sorted live.Contribution No. 151 from the Belle W. Baruch Institute for Marine Biology and Coastal Research. This research was supported by the Oceanography Section, National Science Foundation, NSF Grant GA-42792, and GC-00005 to Duke University for R.V. Eastward operations.     

The effects of ammonium and phosphate enrichments on clorophyll a,pigment ratio and species composition of phytoplankton of Vineyard Sound

Seawater containing natural phytoplankton populations from Vineyard Sound, USA was enriched in the laboratory with three levels each of ammonium and phosphate and with a combination of ammonium and phosphate which provided three different N:P ratios. The addition of ammonium produced more cells and chlorophyll a than the control or the phosphate enrichments. However, enrichment with ammonium and phosphate, regardless of the N:P ratio, yielded the most cells and chlorophyll a. Thus, nitrogen seems to be the primary limiting nutrient, with phosphate showing secondary limiting effects. The ratios of photosynthetic pigments decreased with the increased chlorophyll a production in the enriched cultures. There were no significant changes in the species composition within the cultures, so that the observed changes in pigment ratio and chlorophyll a content were due to physiological responses.     

Genetic differentiation between spatially-disjunct populations of the deep-sea,hydrothermal vent-endemic amphipod Ventiella sulfuris

Species endemic to deep-sea hydrothermal vent ecosystems have disjunct distributions imposed by the island-like arrangement of their specialized habitats. Using allozyme electrophoresis, we examined genetic population structure of the hydrothermal vent amphipod Ventiella sulfuris Barnard and Ingram, 1990. Samples from five sites along the East Pacific Rise (EPR) and two along the Galapagos Rift were collected in 1990 and 1988, respectively. Variability, based on 12 enzyme loci, was relatively high (proportion of polymorphic loci whose most common allele not greater than 0.95 in frequency) =41.6%; (mean heterozygosity) =0.158] compared with shallow-water marine and freshwater amphipods, and similar to the deep-sea lysianassid Eurythenes gryllus. Genetic divergence among populations spread along a cöntiguous rift axis (i.e., EPR) was low [Nei's genetic distance (D) ranged from <0.001 to 0.018]. Genetic tructure analysis suggests that along a contiguous ridge axis migration occurs in a stepping stone manner and is unconstrained by distances as great as 1200 km (migration rate, , ranged from 1.9 to 67.8 ind. generation^–1). However, genetic divergence between populations on disjunct ridge axes was extremely high (D ranged from 0.438 to 0.476). Most of the variance in gene frequencies was due to the differences between the major subpopulations inhabiting the two distinct ridge axes, EPR and Galapagos Rift. Apparently, very little migration and gene flow occur between these major subpopulations (M1). This level of genetic divergence may be sufficient to justity separation of EPR and Galapagos Rift populations at the species level. Futher analyses of morphological characters is required before taxonomic status can be assigned.     

Aspects of sodium regulation in a brackish-water and a marine species of the isopod genus Sphaeroma

Sodium and chloride concentrations of the haemolymph were determined in Sphaeroma rugicauda Leach and S. serratum Fabricius acclimatized to a range of salinities. Sodium loss and uptake (using ²²Na) were measured in salinities below 1.1 for S. rugicauda and 7.2 for S. serratum. Potential differences between haemolymph and medium indicate active uptake of both ions in certain salinities. The active-uptake component of total sodium-influx was found to be related non-linearly to the sodium concentration of the medium. Curves of were fitted to the activeuptake data. Km values indicate that, in S. rugicauda, the sodium uptake system has a greater affinity for sodium than in S. serratum. These findings are discussed in relation to the distribution of each species.     

Distribution and phytoavailability of antimony at an antimony mining and smelting area,Hunan, China

An investigation of the distribution, fractionation and phytoavailability of antimony (Sb) and other heavy metals in soil sampled at various locations in the vicinity of a Sb mine revealed elevated levels of Sb, most certainly due to the mining activities. The concentration of Sb in the soil samples was 100.6–5045 mg kg⁻¹; in comparison, the maximum permissible concentration for Sb in soil in The Netherlands is 3.5 mg kg⁻¹, and the maximum permissible concentration of pollutant Sb in receiving soils recommended by the World Health Organization is 36 mg kg⁻¹. The soil sampled near the Sb mine areas had also contained high concentrations of As and Hg. Root and leaf samples from plants growing in the Sb mine area contained high concentrations of Sb, with the concentration of Sb in the leaves of radish positively correlating with Sb concentrations in soil. The distribution of Sb in the soil showed the following order: strongly bound to the crystalline matrix > adsorbed on Fe/Mn hydrous oxides, complexed to organic/sulfides, bound to carbonates > weakly bound and soluble. Solvents showed varying levels of effectiveness in extracting Sb (based on concentration) from the soil, with , in decreasing order. The concentration of easily phytoavailable Sb was high and varied from 2.5 to 13.2 mg kg⁻¹, the percentage of moderately phytoavailable Sb ranged from 1.62 to 8.26%, and the not phytoavailable fraction represented 88.2–97.9% of total Sb in soils.     

Genetic parentage in the indigo bunting: a study using DNA fingerprinting

Summary Parentage of nestlings in a North Carolina population of indigo buntings (Passerina cyanea) was analyzed using DNA fingerprinting. Three minisatellite DNA probes (wild type M13, Jeffreys' 33.15 and 33.6) were used to analyze nuclear DNA isolated from muscle biopsies of 63 nestlings, their parents, and other local adults. Each probe detected approximately 15 scorable fragments per individual, with 18%–39% overlap between probes. The proportion of bands shared (using all fragments over all three probes) between presumably unrelated adults averaged 0.23. Of the 63 offspring analyzed, 35 had at least one fragment not present in either putative parent. The distribution of offspring with novel fragments was distinctly bimodal. The lower mode (offspring with 0, 1, or 2 novel fragments, N=41) fit a Poisson distribution, a pattern expected if mutation (estimated rate per fragment= 0.01) were the source of the novel fragments. The remaining 22 offspring had more novel fragments than could be explained by mutation alone (minimum of four independent fragments across all three probes, =8.2). A low band-sharing proportion with the resident male ( =0.24) and high band-sharing with the resident female ( =0.60) implicated extra-pair fertilizations as the source of all 22. Thus in this sample, 35% of all nestlings came from extra-pair fertilizations and none from intra-specific brood parasitism. Of 25 broods sampled, 12 (48%) had at least one excluded offspring. In 3 broods all of the offspring excluded the resident male. Band-sharing proportions between excluded nestlings within a brood could not distinguish between single and multiple extra-pair paternity. Although young males tended to be excluded less often than older males, wing length and weight were not associated with the frequency of exclusion. Weight and wing length of females also were not associated with involvement in EPCs. Six of the 22 excluded offspring (in 3 broods) shared a large proportion of bands and had fewer than four novel fragments when compared to the fingerprints of a neighboring territorial male, implicating those males as actual fathers. The parentage of the remaining 16 offspring (in 9 broods) could not be clearly assigned because (1) one or more neighbors were not sampled or (2) difficulties in scoring across gels prevented confident alignment of fingerprint bands, and insufficient DNA was obtained from muscle samples to allow reanalysis of potential actual fathers on the same gel as excluded nestlings.     

Application of the 45Ca tracer method for determination of calcification rates in calcareous algae: Effect of calcium exchange and differential saturation of algal calcium pools

Calcium exchange and differential saturation of algal calcium pools complicate the application of the ⁴⁵Ca tracer method for the determination of net deposition rates of calcium in calcareous algae. The kinetics of ⁴⁵Ca uptake is critically reevaluated, and it is shown that incorporation occurs in two stages. A fast stage, saturating the exchangeable calcium pools; and a slow stage, giving rise to net deposition. The reliability of the method much depends on the determination of the second rate constant. Calcium net-deposition rates are obtained from the expression , where represents the second rate constant and S _SW the specific activity of the seawater. Calcium exchange and recycling of tracer would lower the second rate constant, hence the method will give rise to minimum values. The application of the method is demonstrated for the following algae: Halimeda incrassata, H. opuntia, Penicillus pyriformis, Udotea flabellum, Cymopolia barbata, Padina sanctae crucis and Amphiroa fragilissima; the results show close agreement of data with independent chemical estimates.Sonderforschungsbereich 95 der Universität Kiel, Publication No. 200.Contribution No. 732 from the Bermuda Biological Station for Research.