Calymperastrum,a new genus of Pottiaceae

Abstract

Annual growth rate and spore and capsule production was studied in 50 colonies of the epixylic hepatic, Ptilidium pulcherrimum in northern Sweden. Radial growth rate was independent of colony size but varied from year to year (mean value 5.2 mm year^?1, range 3.5–6.3 mm year^?1). Size at first sporophyte production was estimated to be 68 cm² and the age of first reproduction was estimated to be about 9 years. It was estimated that antheridia were formed the third year. No correlation between growth rates and reproduction was observed. Capsule density as well as capsule and spore production increased significantly with increased colony size. Differences between years in spore and capsule production (up to six-fold) were observed. The mean number of spores per capsule was 27 400 but significant differences between colonies (range from 18 000 to 44 000) were observed.     

Determining the optimal interval for imaging surveillance of ascending aortic aneurysms

BackgroundCardiovascular guidelines recommend (bi-)annual computed tomography (CT) or magnetic resonance imaging (MRI) for surveillance of the diameter of thoracic aortic aneurysms (TAAs). However, no previous study has demonstrated the necessity for this approach. The current study aims to provide patient-specific intervals for imaging follow-up of non-syndromic TAAs.MethodsA total of 332 patients with non-syndromic ascending aortic aneurysms were followed over a median period of 6.7 years. Diameters were assessed using all available imaging techniques (echocardiography, CT and MRI). Growth rates were calculated from the differences between the first and last examinations. The diagnostic accuracy of follow-up protocols was calculated as the percentage of subjects requiring pre-emptive surgery in whom timely identification would have occurred.ResultsThe mean growth rate in our population was 0.2 ± 0.4 mm/year. The highest recorded growth rate was 2.0 mm/year, while 40.6% of patients showed no diameter expansion during follow-up. Females exhibited significantly higher growth rates than men (0.3 ± 0.5 vs 0.2 ± 0.4 mm/year, p = 0.007). Conversely, a bicuspid aortic valve was not associated with more rapid aortic growth. The optimal imaging protocol comprises triennial imaging of aneurysms 40–49 mm in diameter and yearly imaging of those measuring 50–54 mm. This strategy is as accurate as annual follow-up, but reduces the number of imaging examinations by 29.9%.ConclusionsIn our population of patients with non-syndromic TAAs, we found aneurysm growth rates to be lower than those previously reported. Yearly imaging does not lead to changes in the management of small aneurysms. Thus, lower imaging frequencies might be a good alternative approach.     

Coral growth in subtropical eastern Australia

 Extension rates of corals at two sites in subtropical eastern Australia (Solitary Islands and Lord Howe Island) were measured to determine whether growth was low relative to tropical locations. Growth was measured using alizarin staining of skeletons and X-radiographic analysis, and was compared between colonies, species, and sites. Linear extension of individual Pocillopora damicornis colonies averaged 12.4 to 16.1 mm per year at Solitary Islands and Lord Howe Island respectively, which is 50% to 80% of published values for this species at tropical sites. Similarly, average extension of most massive faviid species examined at these sites was between 2.6 mm and 4.6 mm per year, considerably lower than most values reported from lower latitudes (generally 6 mm to 10 mm per year). However, growth rates of Acropora yongei, Turbinaria frondens, and Porites heronensis were close to those of closely-related taxa from the tropics. Causal links between latitude, growth rates of coral colonies, and the potential for reef accretion remain unclear. Accepted: 22 April 1999     

Ammonium uptake usingUlva (Chlorophyta) in intensive fishpond systems: mass culture and treatment of effluent

A vegetative clone ofUlva lactuca L. was selected for mass culture and nutrient uptake experiments with fish pond wastewater. Growth rates of over 55 g dry wt. d^?1 per 6001(1 m²) tank were obtained. Growth rate was linked to stocking density, tank flushing rates and aeration induced thallus movement. The plants could not survive on the macronutrients provided by a weekly pulse of wastewater. A continuous supply of fish pond wastewater was required to maintain good growth rates. An ‘uncoupling’ of growth rate and thallus nitrogen content was observed. The plants were able to store nitrogen from a pulsed ammonium supply and allot the nitrogen reserves to new tissue growth. Plants with slower growth rates or a continuous supply of ammonium had higher thallus nitrogen content.Ulva efficiently removed up to 85% of the ammonium from fish pond wastewater in darkness or light independently of temperature fluctuations.     

Dendrochronology and dendroclimatology of Ceiba speciosa (A. St.-Hil.) Ravenna (Malvaceae) exposed to urban pollution in Rio de Janeiro city,Brazil

Nowadays, the biological monitoring through the growth rings has received increasing attention from ecologists and toxicologists. Structural analysis of these rings allows the incorporation of a time component in the study of plant responses to environmental variation. This allows also to evaluate long time series from the woody plants. In this paper, we assessed the dendrochronological characteristics of Ceiba speciosa growing in forest environment and under urbanization impact. Stem samples were obtained with Pressler probe into trees growing the campus of the Oswaldo Cruz Foundation, adjacent to one of the main urban thoroughfares of the city of Rio de Janeiro (Avenida Brasil), and at Tinguá Biological Reserve, an important remnant of Atlantic Forest. The samples were processed and analyzed following usual dendrochronological methods, with COFECHA and ARSTAN softwares. A negative exponential curve was used for standardization of the series. The residual chronologies were correlated with precipitation and temperature indexes obtained from NOAA weather database. Growth rings are distinct and annual, marked by bands of marginal parenchyma, thick-walled and radially flattened fibres in latewood and distended rays in earlywood. In both sites, the intercorrelation between the trees was above 0.40. Ages ranged from 11 to 41 years in the urban site and from 27 to 64 years in the forest site. In urban area, mean annual increment and cumulative average growth rates were 6 mm/year and 142.62 mm, respectively. At the forest site, these rates were 4 mm/year and 173.07 mm, respectively. The comparison between cumulative radial increment of the two sites revealed that trees of the urban site had higher increment rates beginning at the start of their development and consequently, they showed similar diameters despite lower ages. Correlation analysis between the chronologies and climatic factors revealed a positive association between growth and hot and rainy periods for both study sites. However, there is an immediate response of urban trees in relation to the rains and, a late response of forest trees to the same factor. The dry and hot climate, typical of urban environments, and the absence of natural water reserves in urban soil, may explain this more immediate response of urban tree growth to rainfall and temperature indexes. Our results revealed that Ceiba speciosa is a plastic and stress-tolerant species that is able to survive and adapt to polluted urban conditions. These features, along with its wide natural distribution and frequent planting for city landscaping, make this species an important biomarker for environmental monitoring studies.     

Recruitment and growth of juvenile yellowfin bream, Acanthopagrus australis Günther (Sparidae), in an Australian intermittently open estuary

Recruitment and growth of juvenile yellowfin bream, Acanthopagrus australis Günther (Sparidae), an economically important species, were examined in an intermittently open Australian estuary for 13 months. Fish had a mean fork length of 77.9 (± SE 9.5) mm after 1 year. Growth rates were faster than those found in previous studies in permanently open estuaries and appeared to be dependent upon the water temperature, which ranged from 0.04 mm/day in winter to 0.67 mm/day during summer. However, periods of slower growth may also reflect the emigration of larger fish from the cohort when the estuary was open and which coincided with lower water temperatures. Growth and length-at-age of fish using length-frequency data may be estimated more accurately in intermittently open estuaries because the time of recruitment can be determined, especially when the estuary opening period is short.     

Embryonic duration and post-embryonic growth rates of the tropical freshwater shrimp Caridina nilotica (Decapoda:Atyidae) under laboratory and experimental field conditions

SUMMARY. Embryonic durations and post embryonic growth rates of Caridina nilotica were determined under laboratory conditions at constant temperatures near 18, 24 and 30°C. Embryonic durations and intermoult intervals were negative curvilinear functions of temperature. At a given temperature moulting frequency varied inversely with shrimp size and slight sexual differences were apparent. Moulting frequency of berried females was governed by the temperature-specific embryonic durations. Growth rates were determined from changes in carapace length (CL) of individual shrimps (laboratory) or batches of shrimps (field enclosures) over 1 month and these data were used to calculate temperature-specific life-long growth curves for males and females. Growth in body mass was estimated indirectly from the carapace length-mass relationship of C. nilotica. On average, males grew marginally faster than females during the first 2 months of life, but growth of males larger than CL= 4 mm was considerably depressed relative to that of females. Inflexions in growth rate, apparently related to the onset of sexual maturity, were apparent in both sexes. Under laboratory conditions, the growth rate of males increased with temperature, but temperature-related differences were not as marked in females. Notwithstanding the more rapid moulting rate at 30°C the growth rate of females was slightly slower at 30 than at 24°C as a result of marginally but significantly smaller per moult growth increments observed at 30°C in animals up to CL= 5.5 mm. Possible reasons for this depressed growth are discussed. Growth rates of animals in field enclosures in Lake Sibaya over 1 month in winter (20 ± 3°C) were generally comparable to those estimated for the 18°C laboratory experiments. Growth rates in enclosures containing tripled standing stocks were almost identical to those containing the naturally occurring biomass of animals, suggesting a non-limited environment at least during the time of the experiment.     

Experiments on the growth of Penaeus vannamei Boone

Growth rates of Penaeus vannamei Boone were estimated from field and laboratory experiments using both marked and unmarked shrimp. Field results with unmarked shrimp indicated growth rates of between 0.05 mm increase in carapace length per day (mm c.l./day) and 0.17 mm c.l./day, although rates of up to 0.31 mm c.l./day were also recorded. Moult intervals ranged from5.5 to 34 days with a mean of 12.5 days. Moult increment ranged from 0.2 mm c.l./moult to 1.4 mm c.l./moult with an overall mean of 0.7 mm/moult. Growth was negatively correlated with size over all size ranges, with a marked decrease in growth rate occurring at about 28 mm c.l. Shrimp marked with Floy streamer tags generally grew more slowly than unmarked shrimp, but this was exaggerated by the stress of regular handling in some experiments. The relevance of these findings is discussed in relation to the existing commercial fishery.     

Seasonal Hair Growth in the Adult Domestic Cat (Felis catus)

Determination of amino acid requirements by the factorial method requires an estimate of the amount of amino acids required for the replacement of hair. Hair growth rates in a total of 39 adult male and female domestic short-haired cats were determined throughout the year using the mid-side patch technique. The ratio of hair on the mid-side area to total hair on the body was also determined to allow conversion of mid-side hair growth rates to hair growth rates over the entire body. The mid-side hair growth rate showed a sinusoidal pattern throughout the year, similar to that found for day length and daily mean air temperature, with a maximum hair growth rate of 289 μg/cm²/day in summer and a minimum hair growth rate of 62 μg/cm²/day in winter. The peak hair growth rate for the female cats was reached earlier than that for the male cats. Sine-functions describing day length, minimum and maximum daily air temperatures and daily hair growth rates are presented. Adult domestic short-haired cats were found to grow 32.7 g of hair per kg body weight per year. Monthly amounts of hair growth per unit of body weight and body surface area are calculated.     

THE EFFECTS OF LIGHT AND TEMPERATURE ON GROWTH RATES IN BOREAL-SUBARCTIC CRUSTOSE CORALLINES1

A number of boreal-subarctic crustose corallines were kept in natural seawater tanks at temperatures ranging from 0 to 19 C and, using fluorescent lamps at light intensities, ranging from 7 to 750 lux with periods of 8 and 14 hr/day. The resultant growth rates as a function of temperature and light are presented and discussed in relation to the ecology of the plants. All of the Lithothamnieae studied had growth maxima at temperatures from 9 to 15 C. Growth in these species showed little light dependence below 4–6 C, but had a strong light dependence at higher temperatures. The one Lithophyllum species examined gave a flatter growth-temperature curve than the Lithothamnieae and showed little light dependence. The effects of temperature variation, salinity, and current on growth rates were also examined and are discussed. It was found to be especially important in studying growth rates of crustose corallines to allow time for growth stabilization following temperature change. In general, growth was found to exhibit a hysteresis effect, increased rates with the raising of temperatures 5–10 C and decreased rates with lowering temperatures.     

Microsite requirements,population structure and growth of the cushion plant Azorella compacta in the tropical Chilean Andes

Abstract In the altiplano of northern Chile, we investigated the microsite habitats, adult population structure and growth rates over 14 months for the giant cushion plant Azorella compacta. The majority of plants (52.0%) were found growing downslope of large (>50 cm diameter) boulders and on north‐facing rocky slopes with a slope angle greater than 10° inclination (44.4%). Size was used as a surrogate for age. The youngest size class was most common; remaining size classes were roughly equal in frequency; but very large cushions were scarce. Growth rates were expressed as height, diameter and perimeter over a 14‐month period. Height increased an average of 1.40 cm, perimeter increased an average of 10.28 cm and diameters actually decreased 2.30 cm, although this was not a significant difference. Using perimeter averages based on mean plant size, we estimated a radial growth rate of 1.70 cm per 14 months. Trenches 4 cm wide were cut over the length of five plants, and these trenches were nearly repaired after 1 year, indicating that growth is overall and not just on the perimeter of the plant. These findings indicate that although Azorella compacta populations may be recovering from past exploitation, future monitoring is still necessary to ensure viable populations.     

Population size and reproduction of Gentians nivalis L. at ben lawers N.N.R.

Summary

Life history, reproductive performance, changes in plant numbers, and damage due to grazing were recorded from populations of Gentiana nivalis L. at one of its only two stations in Scotland. Up to 50 per cent of plants were biennials. These were larger than the annuals, produced more seeds, but were grazed preferentially and had poor survival. The production of seed capsules by plants exposed to grazing, mainly by sheep, was less than that of plants on inaccessible cliffs. Overall annual seed production within the main population was 3–4 seeds per m², some 150–200 times greater than the density of the plants. Seeds were deeply dormant and difficult to germinate in the laboratory. The density of G. nivalis was relatively stable within the largest and most dense population, although plants migrated within the area of suitable habitat from one year to the next. Numbers were unstable within small, sparse populations: plants disappeared one year only to reappear a year later. Viable seeds stored in the soil may enable G. nivalis to recolonize rapidly whenever conditions are suitable, thus decreasing the probability of extinction.     

NUTRITIONAL STUDIES OF TWO RED ALGAE. I. GROWT RATE AS A FUNCTION OF NITROGEN SOURCE AND CONCENTRATION1

Gracilaria foliifera (Forsskal) Borgesen and Neoagardhiella bailiyi (Harvey ex Kiitzing) Wynne & Taylor were grown in continuous-flow culture under controlled environmental conditions in 15 liter experimental chambers. Growth rate was related to the source and concentration of nitrogen enrichment supplied to the plants, Growth rate appeared to follow saturation-type nutrient uptake kinetics for plants receiving ammonium, nitrate, urea of sewage effluent enrichments. Ammonium enrichment produced higher growth rates than nitrate of sewage enrichment. The lowest growth rates occurred in the chambers receiving unenriched seawater or urea. The low estimated constants (K) for growth were in the range of 0.2–0.4 (M N for all N enrichments examined. The low estimated values of K compare closely with those found for microalgae and indicate that both species possess the ability to utilize very low concentrations of N.     

Growth patterns of Mytilopsis leucophaeata,an invasive biofouling bivalve in Europe

Abstract

For the first time, growth of Mytilopsis leucophaeata, an important European fouling species, was investigated. By means of growth cages, individual shell growth of three cohorts, with, respectively, initial shell lengths of ≤5 mm, 10 mm and 15 mm, was monitored in the harbour of Antwerp, Belgium, during 2003 – 2004. M. leucophaeata followed an oscillatory growth pattern with a single summer growing period per year (May to August). Growth decreased during wintertime, but never ceased completely. M. leucophaeata has an average growth rate of <3 – 6 mm year^?1. Temperature was found to be the main environmental factor affecting growth. The von Bertalanffy growth function was used to model growth of individuals ≤5 mm, resulting in L_∞ = 16.7 mm and K = 0.56. Based on a combination of growth of all three cohorts, the hypothetical growth of an average individual mussel could be modelled over a 5-year period, resulting in a maximum length >19 mm with a growth rate of 0.41. Its longevity (more than 5 years) and the positive effect of higher water temperatures on growth, combined with its high resistance to chlorination, provides M. leucophaeata with a high potential for severe and long-lasting biofouling     

Some observations on the growth rates of mosses associated with Tufa and the interpretation of some postglacial bryoliths

Abstract

Growth rates were obtained for four mosses associated with tufa deposits. Rates per annum were as follows: Cratoneuron commutatum var. commutatum, 1–4 mm; Eucladium verticillatum, 2–3 mm; Gymnostomum recurvostrum, 1–3; Rhynchostegium riparioides, ca 30 mm. The results are discussed with reference to tufa deposition, water chemistry and water flow. A method for identifying bryophyte remains in postglacial tufa is also described.     

Habitat specific growth rates and condition indices for the sympatric soles Solea solea (Linnaeus, 1758) and Solea senegalensis Kaup 1858, in the Tagus estuary, Portugal, based on otolith daily increments and RNA-DNA ratio

Habitat specific growth rates and condition indices were estimated for Solea solea and Solea senegalensis, in two nursery areas within the Tagus estuary, at the end of the estuarine colonization process, in 2005. While in the uppermost nursery area the two species of sole live in sympatry, in the lower nursery only S. senegalensis is present. Daily increments of left lapillar otoliths were used to estimate age (in days) and determine growth rates (mm per day). Condition indices were assessed through RNA‐DNA ratio in muscle samples. Growth rates were higher for S. senegalensis (0.970and 1.180 mm per day in nursery A and B, respectively) than for S. solea (0.767 mm per day in nursery A). Growth rates of S. senegalensis from the uppermost nursery area were lower when compared to those obtained for the other nursery. The RNA/DNA condition index followed the general trend given by the growth rate estimates, i.e. values were higher for S. senegalensis than for S. solea. However, no significant differences were detected in S. senegalensis from the two nurseries. Larger variations in salinity (10‰ amplitude in the uppermost nursery vs 0.2‰ in the lower nursery) and highest pollution loads may be important factors lowering the habitat quality of the uppermost nursery in comparison to the lower nursery. The use of growth rate estimates based on otolith readings and the RNA/DNA index as tools for habitat quality assessment was discussed.     

AGE AND GROWTH OF THE SQUID LOLIGO VULGARIS OFF THE SOUTH COAST OF PORTUGAL, USING STATOLITH ANALYSIS

Age composition and growth rates of the squid Loligo vulgaris(Lamark, 1797) were studied by examination of growth incrementswithin statohths of 419 specimens (mantle length, ML, rangingfrom 32 to 400 mm). The squid were obtained by monthly samplingfrom the catches of commercial trawls off southern Portugalbetween March and September, 1993 The total number of growthincrements in the mounted and ground statohths was counted usinga semi-automatic image analysis system. ML was significantlycorrelated with both the statolith length, TSL and the numberof increments, NI. The female statolith was slightly largerthan the male statolith for the same mantle size. Growth ratesof individuals showed high variability with an average estimatedat 34.6 mm month^–1 for males and 33.5 mm month^–1for females. Growth in length between 70 and 280 days was bestdescribed by a power function for both sexes. The growth indexof the statolith (TSL/NI) decreased with individual growth.This result may be related with the onset of sexual maturation.L. vulgaris hatched throughout the year with two distinct peaks,in spring which is the mam breeding period, and in autumn. Thelife cycle of the L. vulgaris population on the south Portugueseshelf was completed in one year ^*Present address for correspondence: Instituto de InvestigacionMariflas. Eduardo Cabello. 6 - 36208 VIGO. Spain (Received 28 November 1995; accepted 7 February 1996)     

Temperature-dependent growth and life cycle of Deleatidium (Ephemeroptera: Leptophlebiidae) in two high-country streams in New Zealand

1. Measurements of larval growth rates were used to produce an empirical model for examining factors influencing patterns of size structure and emergence period for populations of the leptophlebiid mayfly Deleatidium ( lillii group) in two high-country streams (South Island, New Zealand). Growth rates were measured in situ by enclosing groups of larvae and natural stream substrata in growth chambers.
2. Multiple regression analysis showed that temperature explained most variation among growth rates in both streams. Growth rates were also significantly related to larval size, although the effect was minor compared with temperature. A significant relationship between larval biomass per chamber and growth rate was shown at only one site.
3. Growth models based on multiple regression equations ( R ² = 0.70–0.84) simulated the extended emergence period and complex size structure observed for populations of Deleatidium in the field. Larvae hatching from eggs deposited before mid-February (austral summer) probably emerge as adults before May (minimum cohort duration ≈ 3 months). Larvae hatching after mid-February probably do not emerge as adults until the following summer because of low growth rates during winter (maximum cohort duration ≈ 11 months).
4. On average, there are probably two generations of Deleatidium per year (bivoltine) at the study sites. The presence of numerous overlapping cohorts throughout summer, however, results in an extended emergence period and complex size structure.     

Temperature-dependent growth and life cycle of Deleatidium (Ephemeroptera: Leptophlebiidae) in two high-country streams in New Zealand

1. Measurements of larval growth rates were used to produce an empirical model for examining factors influencing patterns of size structure and emergence period for populations of the leptophlebiid mayfly Deleatidium ( lillii group) in two high-country streams (South Island, New Zealand). Growth rates were measured in situ by enclosing groups of larvae and natural stream substrata in growth chambers.
2. Multiple regression analysis showed that temperature explained most variation among growth rates in both streams. Growth rates were also significantly related to larval size, although the effect was minor compared with temperature. A significant relationship between larval biomass per chamber and growth rate was shown at only one site.
3. Growth models based on multiple regression equations ( R ² = 0.70–0.84) simulated the extended emergence period and complex size structure observed for populations of Deleatidium in the field. Larvae hatching from eggs deposited before mid-February (austral summer) probably emerge as adults before May (minimum cohort duration ≈ 3 months). Larvae hatching after mid-February probably do not emerge as adults until the following summer because of low growth rates during winter (maximum cohort duration ≈ 11 months).
4. On average, there are probably two generations of Deleatidium per year (bivoltine) at the study sites. The presence of numerous overlapping cohorts throughout summer, however, results in an extended emergence period and complex size structure.     

Growth and survival strategy of the Antarctic mite Alaskozetes antarcticus

Growth and mortality rates of three juvenile instars and adults of the oribatid mite Alaskozetes antarcticus were measured over a twelve month period using field enclosures m Its maritime Antarctic habitat A pattern was found of rapid growth during the short summer period (0 2-0 4 μg dry weight increment per day) followed by gradual weight loss overwinter Most individuals completed one instar per year, reaching a premoult resting phase by late summer, with the moult being delayed and relatively synchronised early the next summer A small proportion of proto- and deutonymphs completed two moults within one summer period After the final moult adults overwintered again before commencing oviposition, suggesting that the life cycle (egg-egg) will take at least five years Mortality was not biased towards any instar or time of year Highest individual growth rates were obtained at a constant temperature of 7°C in the laboratory However expenmentai increase of mean field temperature from 2 7 to 4 3°C by use of a plastic cloche led to decreased growth, although no change in moulting frequency or mortality rate Laboratory survival was greatest at 2°C and decreased with increasing temperature
Alaskozetes antarcticus may be descnbed as 'a' (adversity) selected, showing an exceptionally long life cycle of five to six years and extensive physiological investment in survival adaptations Moult synchronisation in early summer, involving entering winter in the inactive premoult phase, will increase overwinter survival by reducing the chance of inoculative freezing from gut contents, and may be advantageous in maximising the time available for feeding during the subsequent summer, or ensuring proximity of the sexes after the final moult