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1.
Yun Hee Kang Jong Ahm Shin Myung Sook Kim Ik Kyo Chung 《Journal of applied phycology》2008,20(2):183-190
In integrated multi-trophic aquaculture (IMTA), seaweeds have the capacity to reduce the environmental impact of nitrogen-rich
effluents in coastal ecosystems. To establish such bioremediation systems, selection of suitable seaweed species is important.
The distribution and productivity of seaweeds vary seasonally based on water temperature and photoperiod. In Korea, candidate
genera such as Pophyra, Laminaria, and Undaria grow from autumn to spring. In contrast, Codium grows well at relatively high water temperatures in summer. Thus, aquaculture systems potentially could capitalize on Codium’s capacity for rapid growth in the warm temperatures of late summer and early fall. In this study, we investigated ammonium
uptake and removal efficiency by Codium fragile. In laboratory experiments, we grew C. fragile under various water temperatures (10, 15, 20, and 25°C), irradiances (dark, 10, and 100 μmol photons m−2 s−1), and initial ammonium concentrations (150 and 300 μM); in all cases, C. fragile exhausted the ammonium supply for 6 h. At 150 μM of , ammonium removal efficiency was greatest (99.5 ± 2.6%) when C. fragile was incubated at 20°C under 100 μmol photons m−2 s−1. At 300 μM of , removal efficiency was greatest (86.3 ± 2.1%) at 25°C under 100 μmol photons m−2 s−1. Ammonium removal efficiency was significantly greater at 20 and 25°C under irradiance of 100 μmol photons m−2 s−1 than under other conditions tested. 相似文献
2.
Margareth da Silva Copertino Thiago Tormena Ulrich Seeliger 《Journal of applied phycology》2009,21(1):31-45
The growth, biofiltering efficiency and uptake rates of Ulva clathrata were studied in a series of outdoor tanks, receiving waste water directly from a shrimp (Litopenaeus vannamei) aquaculture pond, under constant aeration and two different water regimes: (1) continuous flow, with 1 volume exchange a
day (VE day-1) and (2) static regime, with 1 VE after 4 days. Water temperature, salinity, pH, dissolved inorganic nitrogen (DIN), phosphate
(PO4), chlorophyll-a (chl-a), total suspended solids (TSS), macroalgal biomass (fresh weight) and tissue nutrient assimilation were monitored over 12 days.
Ulva clathrata was highly efficient in removing the main inorganic nutrients from effluent water, stripping 70–82% of the total ammonium
nitrogen (TAN) and 50% PO4 within 15 h. Reductions in control tanks were much lower (Tukey HSD, P < 0.05). After 3 days, the mean uptake rates by the seaweed biomass under continuous flow were 3.09 mg DIN g DW day−1 (383 mg DIN m−2 day−1) and 0.13 mg PO4 g DW day−1 (99 mg PO4 m−2 day−1), being significantly higher than in the static regime (Tukey HSD, P < 0.05). The chl-a decreased in seaweed tanks, suggesting that U. clathrata inhibited phytoplankton growth. Correlations between the cumulative values of DIN removed from the water and total nitrogen
assimilated into the seaweed biomass (r = 0.7 and 0.8, P < 0.05), suggest that nutrient removal by U. clathrata dominated over other processes such as phytoplankton and bacterial assimilation, ammonia volatilization and nutrient precipitation. 相似文献
3.
Invasion by a Perennial Herb Increases Decomposition Rate and Alters Nutrient Availability in Warm Temperate Lowland Forest Remnants 总被引:3,自引:0,他引:3
Rachel J. Standish Peter A. Williams Alastair W. Robertson Neal A. Scott Duncan I. Hedderley 《Biological invasions》2004,6(1):71-81
We determined the impact of the invasive herb, Tradescantia fluminensis Vell., on litter decomposition and nutrient availability in a remnant of New Zealand lowland podocarp–broadleaf forest. Using
litter bags, we found that litter beneath mats of Tradescantia decomposed at almost twice the rate of litter placed outside the mat. Values of k (decomposition quotient) were 9.44±0.42 yrs for litter placed beneath Tradescantia and 5.42±0.42 yrs for litter placed in native, non-Tradescantia plots. The impact of Tradescantia on decomposition was evident through the smaller forest floor mass in Tradescantia plots (2.65±1.05 t ha−1) compared with non-Tradescantia plots (5.05±1.05 t ha−1), despite similar quantities of annual leaf litterfall into Tradescantia plots (6.85±0.85 t ha−1 yr−1) and non-Tradescantia plots (7.45±1.05 t ha−1 yr−1). Moreover, there was increased plant nitrate available, as captured on resin bags, in Tradescantia plots (25.77 ± 8.32 cmol(−)/kg resin) compared with non-Tradescantia plots (9.55±3.72 cmol(−)/kg resin). Finally, the annual nutrient uptake by Tradescantia represented a large proportion of nutrients in litterfall (41% N, 61% P, 23% Ca, 46% Mg and 83% K), exceeded the nutrient
content of the forest floor (except Ca), but was a small proportion of the topsoil nutrient pools. Taken together, our results
show that Tradescantia increases litter decomposition and alters nutrient availability, effects that could influence the long-term viability of
the majority of podocarp–broadleaf forest remnants affected with Tradescantia in New Zealand. These impacts are likely mostly due to Tradescantia's vegetation structure (i.e., tall, dense mats) and associated microclimate, compared with native ground covers.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
The use of amiloride to uncouple branchial sodium and proton fluxes in the brown trout, Salmo trutta
I. D. Nelson W. T. W. Potts H. Huddart 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(2):123-128
Resting proton, ammonium and sodium fluxes in Salmo trutta were 492.6 ± 19.5 (n = 29); 122.9 ± 34.2 (n = 28) and 277.1 ± 18.5 (n = 50) μmol · kg−1 · h−1, respectively. The resting transepithelial potential was found to be composed of three successive potentials, the outermost
averaging −7.36 ± 0.19mV, the second, −14.3 ± 1.4 mV and the third −37 ± 1.7 mV. Amiloride inhibits the proton, ammonium and
sodium fluxes in a dose-dependent manner at concentrations of 0.5 mmol · 1−1 and 0.1 mmol · l−1, but at 0.01 mmol · l−1, proton and ammonium fluxes remained at control levels whilst the sodium was reduced to 70.59 ± 7.29 μmol · kg−1 · h−1. The trans-epithelial potential was effected in a bi-phasic manner by 0.5 mmol · l−1 amiloride. An initial hyperpolarisation of ca. 6 mV was followed by a sustained depolarisation of ca. 14 mV (towards zero)
which persisted until the amiloride was washed off the gill. The initial hyperpolarisation was thought to reflect a rapid
inhibition of a positive inward sodium current and the subsequent depolarisation was due to the inhibition of a positive outward
current (proton) which would abolish the transepithelial potential. However, at 0.01 mmol · l−1 only the hyperpolarisation was seen, due to the inhibition of only the inward sodium current. Acetazolamide (0.1 mmol · l−1) was found to have no significant effect on the proton, ammonium and sodium fluxes. These results indicate that the proton
and sodium fluxes across the gill of the freshwater trout are not tightly linked. While this suggests that the trout gill
resembles the model of Ehrenburg et al. (1985) of sodium uptake in frog skin, the apical potentials measured in the pavement
epithelial cell(s) are too low to account for sodium uptake unless the activity of the sodium in the cells is very low.
Accepted: 8 August 1996 相似文献
5.
In this study, sludge was taken from a municipal wastewater treatment plant that contained a nearly equal number of archaeal
amoA genes (5.70 × 106 ± 3.30 × 105 copies mg sludge−1) to bacterial amoA genes (8.60 × 106 ± 7.64 × 105 copies mg sludge−1) and enriched in three continuous-flow reactors receiving an inorganic medium containing different ammonium concentrations:
2, 10, and 30 mM NH4+–N (28, 140, and 420 mg N l−1). The abundance and communities of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in enriched nitrifying
activated sludge (NAS) were monitored at days 60 and 360 of the operation. Early on, between day 0 and day 60 of reactor operation,
comparative abundance of AOA amoA genes to AOB amoA genes varied among the reactors depending on the ammonium levels found in the reactors. As compared to the seed sludge, the
number of AOA amoA genes was unchanged in the reactor with lower ammonium level (0.06 ± 0.04 mgN l−1), while in the reactors with higher ammonium levels (0.51 ± 0.33 and 0.25 ± 0.10 mgN l−1), the numbers of AOA amoA genes were deteriorated. By day 360, AOA disappeared from the ammonia-oxidizing consortiums in all reactors. The majority
of the AOA sequences from all NASs at each sampling period fell into a single AOA cluster, however, suggesting that the ammonium
did not affect the AOA communities under this operational condition. This result is contradictory to the case of AOB, where
the communities varied significantly among the NASs. AOB with a high affinity for ammonia were present in the reactors with
lower ammonium levels, whereas AOB with a low affinity to ammonia existed in the reactors with higher ammonium levels. 相似文献
6.
Marcel Tutor Ale Jørn Dalgaard Mikkelsen Anne S. Meyer 《Journal of applied phycology》2011,23(3):345-351
Controlled cultivation of marine macroalgal biomass such as Ulva species, notably Ulva lactuca, is currently studied for production of biofuels or functional food ingredients. In a eutrophic environment, this macrophyte
is exposed to varying types of nutrient supply, including different and fluctuating levels of nitrogen sources. Our understanding
of the influences of this varying condition on the uptake and growth responses of U. lactuca is limited. In this present work, we examined the growth response of U. lactuca exposed to different sources of nitrogen (NH4+; NO3−; and the combination NH4NO3) by using photo-scanning technology for monitoring the growth kinetics of U. lactuca. The images revealed differential increases of the surface area of U. lactuca disks with time in response to different N-nutrient enrichments. The results showed a favorable growth response to ammonium
as the nitrogen source. The NH4Cl and NaNO3 rich media (50 μM of N) accelerated U. lactuca growth to a maximum specific growth rate of 16.4 ± 0.18% day−1 and 9.4 ± 0.72% day−1, respectively. The highest biomass production rate obtained was 22.5 ± 0.24 mg DW m−2·day−1. The presence of ammonium apparently discriminated the nitrate uptake by U. lactuca when exposed to NH4NO3. Apart from showing the significant differential growth response of U. lactuca to different nitrogen sources, the work exhibits the applicability of a photo-scanning approach for acquiring precise quantitative
growth data for U. lactuca as exemplified by assessment of the growth response to two different N-sources. 相似文献
7.
Griselda Margarita Rodríguez-Figueroa Evgueni Shumilin Ignacio Sánchez-Rodríguez 《Journal of applied phycology》2009,21(1):19-26
The coastal marine sediments near Santa Rosalía on the eastern coast of the Baja California Peninsula (Mexico) are heavily
polluted by metals due to copper mining and smelting over the past century (up to 1984). The present study compares the accumulation
of metals in the brown seaweed Padina durvillaei from the central segment of the coast of Santa Rosalía (polluted by Co, Cu, Mn and Zn) and from two segments north and south
of the known “hot spot”. The seaweed samples were collected in May and August 2004 and June 2005 at 13 stations located along
the Santa Rosalía mining region. Heavy metal concentrations were measured by instrumental neutron activation analysis (Co
and Fe) directly in dried homogenized subsamples or by flame atomic absorption spectrophotometry (Cd, Cu, Mn, Ni, Pb and Zn)
after complete strong acid digestion of sub-samples. The means and standard deviations of the concentrations in dry tissues
of Padina durvillaei specimens for all the studied metals and stations lie in the following sequence: Cd (3.6 ± 1.6 mg kg−1) < Co (6.5 ± 6.1 mg kg−1) < Pb (7.8 ± 6.2) < Ni (9.96 ± 5.28 mg kg−1) < Cu (53 ± 38 mg kg−1) < Zn (63 ± 43 mg kg−1) < Mn (295 ± 269 mg kg−1) < Fe (2243 ± 2325 mg kg−1). This increase of the average concentrations was statistically significant. Principal Component Analysis showed that Factor
1 (36.46%) displays high positive loadings for Co, Cu, Mn and Zn, reflecting the influence of local anthropogenic pollution
on the seaweed composition, while Factor 2 (26.91%) is important for Co, Fe and Ni and probably corresponds to the adsorption
or accumulation of terrigenous elements of the regional origin, while Factor 3, with a high positive loading for Pb and a
high negative loading for Cd, is probably controlled by local and regional anthropogenic input of Pb and episodic supply of
Cd by local upwellings. The results of ANOVA for each element do not show any significant differences between the average
concentrations for Cd, Fe, Ni and Pb in the seaweed of the three segments, or between the central and southern segments for
Cu, Mn and Zn. Cobalt contents in the seaweed from the northern and central segments are, however, significantly different
from the southern segment. This indicates that element concentrations in Padina durvillaei generally do not follow the drastic increases and gradients of Cu, Co, Mn and Zn contents detected in surface sediments.
The apparent contradiction could be explained by a low geochemical mobility of these metals in the polluted sediments, composed
mainly of stable residues of smelter wastes, with very low content of organic matter usually driving diagenetic mobilization
of some metals into interstitial waters and then to the overlying water. 相似文献
8.
Deborah V. Robertson-Andersson Michelle Potgieter Joakim Hansen John J. Bolton Max Troell Robert J. Anderson Christina Halling Trevor Probyn 《Journal of applied phycology》2008,20(5):579-595
Land-based abalone aquaculture in South Africa, based on the local species Haliotis midae, started in the early 1990s and has grown rapidly in the last decade, with 13 commercial farms now producing over 850 t per
annum. Over 6,000 t per annum of kelp Ecklonia maxima are now harvested for this purpose, and some kelp beds are reaching maximum sustainable limits. Research into seaweed aquaculture
as feed (Ulva and some Gracilaria) for abalone started in the late 1990s on the southeast coast (where there are no kelp beds) using abalone waste water. A
growing body of evidence suggests that a mixed diet of kelp plus other seaweeds can give growth rates at least as good as
compound feed, and can improve abalone quality and reduce parasite loads. A pilot scale Ulva lactuca and abalone integrated recirculation unit using 25% recirculation was designed and built on the south west coast of South
Africa using one 12,000-L abalone tank containing 13,200 15 ± 2.5 g abalone, connected to two 3,000-L seaweed tanks containing
an initial starting biomass of 10 kg of seaweed, replicated 3 times. In an 18-month period, there were no significant differences
in abalone health or growth rates, sediment build up and composition, mobile macro fauna densities and species between the
recirculation or the flow-through units. Transfer of oxygen generated by the seaweeds to the abalone tanks was poor, resulting
in the recirculated abalone tanks having lower (33%) dissolved oxygen concentrations than a comparable flow-through abalone
unit. Seaweed nutrient content and specific growth rates in the units were comparable to seaweeds cultivated in fertilized
effluent (SGR = 3.2 ± 3.4%.day−1; Yield = 0.2 ± 0.19 kg.m2.day−1). Indications were that at this low recirculation ratio the seaweeds in the units were nutrient limited and that there were
no negative effects to the abalone being cultivated in such a recirculation unit at this recirculation ratio. 相似文献
9.
The effects of temperature (20, 24 and 28 °C) and irradiance (15 and 40 μmol photon m−2 s−1) on the nitrate and ammonium uptake rates of the subtropical red alga, Laurencia brongniartii, were investigated to prepare for tank cultivation. Nitrate uptake followed saturation kinetics and was faster at higher
irradiances and temperatures. In contrast, ammonium uptake was linear over the experimental range and was not affected by
an increase in temperature. A parameter, β, was calculated to compare substrate uptake rates of nitrate along the linear portion
of the uptake curve with that of ammonium. For nitrate, β was lower at low irradiance and higher at high irradiance (β = 0.007
± 0.003 and 0.030 ± 0.002 [μmol N L−1 (μmol N gww−1 d−)−1], respectively). However, β was 0.023 ± 0.002 and 0.034 ± 0.002 [μmol N L−1 (μmol N gww−1 d−1)−1] for ammonium, suggesting a preference for ammonium over nitrate. 相似文献
10.
Zeng Jie Jiang Jian Guang Fang Ting Ting Han Yu Ze Mao Jia Qi Li Mei Rong Du 《Journal of applied phycology》2014,26(1):545-550
Respiration and calcification rate were estimated to quantify the effect of Zhikong scallop Chlamys farreri on marine CO2 system in Sanggou Bay, China. The C. farreri population in Sanggou Bay sequestered 78.06?±?5.76 g C m?2 y?1 for shell formation, while the CO2 fluxes due to calcification and respiration were 53.95?±?3.98 and 71.69?±?6.51 g C m?2 y?1, respectively. In order to eliminate the additional CO2 released from calcification and respiration process of C. farreri, Gracilaria lemaneiformis were introduced into the integrated system and its role was validated by in situ mesocosm methods. Eight mesocosms (1,000 L) were deployed over 42-h period and consisted of four treatments: seaweed-only, scallop-only (SP), seaweed integrated with scallop (SS), and control (C). The aqueous CO2 concentration and partial pressure of CO2 in SP treatments were significantly higher than the other three treatments (p?<?0.01), while there were no difference between SS treatments and C treatments (p?>?0.05). Furthermore, compared with the SP treatments, the presence of the G. lemaneiformis can keep the seawater pH stable. These findings suggest that seaweed and shellfish integrated aquaculture practice cannot only reduce dissolved inorganic carbon but also can alleviate ocean acidification. 相似文献
11.
Nitrogen uptake in the infiltration community, an ice algal community in Antarctic pack-ice 总被引:1,自引:0,他引:1
S. Kristiansen T. Farbrot H. Kuosa S. M. Myklestad C. H. von Quillfeldt 《Polar Biology》1998,19(5):307-315
An infiltration community was the dominating ice algal community in pack-ice off Queen Maud Land, Southern Ocean, in January
1993. The community was dominated by autotrophic processes, and the most common species were the prymnesiophyte Phaeocystis antarctica and the diatoms Chaetoceros neglectus and Fragilariopsis cylindrus. The concentration of chlorophyll a was 1.3–47.9 μg l−1, and the inner part of the community was nitrate depleted. Uptake rates of nitrate, nitrite, ammonium, urea and amino acids
were measured using 15N. Nitrate was the major nitrogen source for ice algal growth (67 ± 6% nitrate uptake). It is suggested that % nitrate uptake
in the infiltration community decreases during the growth season, from 92% during spring (literature data) to 67% during summer.
Scalar irradiance in the infiltration community was high and variable. It reached ca. 2000 μmol m−2 s−1 at some locations, and nitrate uptake rate was potentially photoinhibited at irradiances >500 μmol m−2 s−1. Nitrate uptake rate in an average infiltration community (0.6 m of snow cover) was lowered by 13% over a 2-week period due
to photoinhibition.
Received: 16 December 1996 / Accepted: 5 January 1998 相似文献
12.
To identify the importance of arbuscular mycorrhizal fungi (AMF) colonizing wetland seedlings following flooding, we assessed
the effects of AMF on seedling establishment of two pioneer species, Bidens frondosa and Eclipta prostrata grown under three levels of water availability and ask: (1) Do inoculated seedlings differ in growth and development from
non-inoculated plants? (2) Are the effects of inoculation and degree of colonization dependent on water availability? (3)
Do plant responses to inoculation differ between two closely related species? Inoculation had no detectable effects on shoot
height, or plant biomass but did affect biomass partitioning and root morphology in a species-specific manner. Shoot/root
ratios were significantly lower in non-inoculated E. prostrata plants compared with inoculated plants (0.381 ± 0.066 vs. 0.683 ± 0.132). Root length and surface area were greater in non-inoculated
E. prostrata (259.55 ± 33.78 cm vs. 194.64 ± 27.45 cm and 54.91 ± 7.628 cm2 vs. 46.26 ± 6.8 cm2, respectively). Inoculation had no detectable effect on B. frondosa root length, volume, or surface area. AMF associations formed at all levels of water availability. Hyphal, arbuscular, and
vesicular colonization levels were greater in dry compared with intermediate and flooded treatments. Measures of mycorrhizal
responsiveness were significantly depressed in E. prostrata compared with B. frondosa for total fresh weight (−0.3 ± 0.18 g vs. 0.06 ± 0.06 g), root length (−0.78 ± 0.28 cm vs.−0.11 ± 0.07 cm), root volume (−0.49 ± 0.22 cm3 vs. 0.06 ± 0.07 cm3), and surface area (−0.59 ± 0.23 cm2 vs.−0.03 ± 0.08 cm2). Given the disparity in species response to AMF inoculation, events that alter AMF prevalence in wetlands could significantly
alter plant community structure by directly affecting seedling growth and development. 相似文献
13.
Herbert R. L. Drouin 《European biophysics journal : EBJ》1999,28(7):600-604
A new ion-selective liquid membrane microelectrode, based on the neutral carrier 1,1′-bis(2,3-naphtho-18-crown-6), is described
that shows the dependence of EMF on the activity of divalent putrescine cations a
Put, with the linear slope s
Put = 26 ± 3 mV/decade (mean ± SD, N = 18), in the range 10−4–10−1 M at 25 ± 1 °C. Values of potentiometric putrescine cation selectivity coefficients of logK
Pot
Put
j
(mean ± SD, N) are obtained by the separate solution method for the ions K+ (1.0 ± 0.4, 10), Na+ (−1.2 ± 0.4, 8), Ca2+ (−2.3 ± 0.5, 10) and Mg2+ (−2.5 ± 0.5, 7). The microelectrode can be applied for the direct analysis of the activities of free divalent putrescine
cations in the range 5 × 10−4 to 10−1 M in an extracellular ionic environment. Established analytical methods, e.g. high performance liquid chromatography, determine
the total concentration of the derivatives of free and bound putrescine.
Received: 20 December 1998 / Revised version: 7 May 1999 / Accepted: 27 May 1999 相似文献
14.
Moro D Bradshaw SD 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1999,169(8):538-548
A laboratory study investigated the metabolic physiology, and response to variable periods of water and sodium supply, of
two arid-zone rodents, the house mouse (Mus domesticus) and the Lakeland Downs short-tailed mouse (Leggadina lakedownensis) under controlled conditions. Fractional water fluxes for M. domesticus (24 ± 0.8%) were significantly higher than those of L. lakedownensis (17 ± 0.7%) when provided with food ad libitum. In addition, the amount of water produced by M. domesticus and by L. lakedownensis from metabolic processes (1.3 ± 0.4 ml · day−1 and 1.2 ± 0.4 ml · day−1, respectively) was insufficient to provide them with their minimum water requirement (1.4 ± 0.2 ml · day−1 and 2.0 ± 0.3 ml · day−1, respectively). For both species of rodent, evaporative water loss was lowest at 25 °C, but remained significantly higher
in M. domesticus (1.1 ± 0.1 mg H2O · g−0.122 · h−1) than in L. lakedownensis (0.6 ± 0.1 mg H2O · g−0.122 · h−1). When deprived of drinking water, mice of both species initially lost body mass, but regained it within 18 days following
an increase in the amount of seed consumed. Both species were capable of drinking water of variable saline concentrations
up to 1 mol · l−1, and compensated for the increased sodium in the water by excreting more urine to remove the sodium. Basal metabolic rate
was significantly higher in M. domesticus (3.3 ± 0.2 mg O2 · g−0.75 · h−1) than in L. lakedownensis (2.5 ± 0.1 mg O2 · g−0.75 · h−1). The study provides good evidence that water flux differences between M. domesticus and L. lakedownensis in the field are due to a requirement for more water in M. domesticus to meet their physiological and metabolic demands. Sodium fluxes were lower than those observed in free-ranging mice, whose
relatively high sodium fluxes may reflect sodium associated with available food.
Accepted: 16 August 1999 相似文献
15.
To screen stimulators from Chinese medicinal insects for mycelial growth and polysaccharides production of Ganoderma lucidum, G. lucidum was inoculated into the media with and without supplementation of medicinal insect extracts. The ethyl acetate extract of
Eupolyphaga sinensis at 55 mg l−1 lead to significant increase in both biomass and intracellular polysaccharides (IPS) concentration from 8.53 ± 0.41 to 14.16 ± 0.43
and 1.28 ± 0.09 to 2.13 ± 0.11 g l−1, respectively. In addition, the ethyl acetate extract of Catharsius molossus at 55 mg l−1 significantly enhanced extracellular polysaccharides (EPS) production; the EPS yield increased from 350.9 ± 14.1 to 475.1 ± 15.3 mg
l−1. There were no new components in the two types of polysaccharides obtained by the addition of the insect extracts. 相似文献
16.
Nigel J. Adams Berry Pinshow Leonard Z. Gannes 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(6):444-450
We used tritium-labeled water to measure total body water, water influx (which approximated oxidative water production) and
water efflux in free-flying tippler pigeons (Columba livia) during flights that lasted on average 4.2 h. At experimental air temperatures ranging from 18 to 27 °C, mean water efflux
by evaporation and excretion [6.3 ± 1.3 (SD) ml · h−1, n = 14] exceeded water influx from oxidative water and inspired air (1.4 ± 0.7 ml · h−1, n = 14), and the birds dehydrated at 4.9 ± 0.9 ml · h−1. This was not significantly different from gravimetrically measured mass loss of 6.2 ± 2.1 g · h−1 (t = 1.902, n = 14, P>0.05). This flight-induced dehydration resulted in an increase in plasma osmolality of 4.3 ± 3.0 mosmol · kg−1 · h−1 during flights of 3–4 h. At 27 °C, the increase in plasma osmolality above pre-flight levels (ΔP
osm = 7.6±4.29 mosmol · kg−1 · h−1, n = 6) was significantly higher than that at 18 °C (ΔP
osm = 0.83±2.23 mosmol · kg−1 · h−1, (t = 3.43, n = 6, P < 0.05). Post-flight haematocrit values were on average 1.1% lower than pre-flight levels, suggesting plasma expansion. Water
efflux values during free flight were within 9% of those in the one published field study (Gessaman et al. 1991), and within
the range of values for net water loss determined from mass balance during wind tunnel experiments (Biesel and Nachtigall
1987). Our net water loss rates were substantially higher than those estimated by a simulation model (Carmi et al. 1992) suggesting
some re-evaluation of the model assumptions is required.
Accepted: 8 April 1997 相似文献
17.
C. Lydersen K. M. Kovacs M. O. Hammill 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(2):81-88
In this study we measured growth and milk intake and calculated energy intake and its allocation into metabolism and stored
tissue for hooded seal (Cystophora cristata) pups. In addition, we measured mass loss, change in body composition and metabolic rate during the first days of the postweaning
fast. The mean body mass of the hooded seal pups (n = 5) at the start of the experiments, when they were new-born, was 24.3 ± 1.3 kg (SD). They gained an average of 5.9 ± 1.1.
kg · day−1 of which 19% was water, 76% fat and 5% protein. This corresponds to an average daily energy deposition of 179.8 ± 16.0 MJ.
The pups were weaned at an average body mass of 42.5 ± 1.0 kg 3.1 days after the experiment was initiated. During the first
days of the postweaning fast the pups lost an average of 1.3 ± 0.5␣kg of body mass daily, of which 56% was water, 16% fat
and 28% protein. During the nursing period the average daily water influx for the pups was 124.6 ± 25.8 ml · kg−1. The average CO2 production during this period was 1.10 ± 0.20 ml · g−1 · h−1, which corresponds to a field metabolic rate of 714 ± 130 kJ · kg−1 · day−1, or 5.8 ± 1.1 times the predicted basal metabolic rate according to Kleiber (1975). During the postweaning fast the average
daily water influx was reduced to 16.1 ± 6.6 ml · kg−1. The average CO2 production in␣this period was 0.58 ± 0.17 ml · g−1 · h−1 which corresponds to a field metabolic rate of 375 ± 108 kJ · kg−1 · day−1 or 3.2 ± 0.9 times the predicted basal metabolic rate. Average values for milk composition were 33.5% water, 58.6% fat and
6.2% protein. The pups drank an average of 10.4 ± 1.8␣kg of milk daily, which represents an energy intake of 248.9 ± 39.1
MJ · day−1. The pups were able to store 73.2 ± 7.7% of this energy as body tissue.
Accepted: 15 August 1996 相似文献
18.
Gigartina skottsbergii is a commercially important carrageenan producer that has been suffering severe extraction pressure in Chile’s Magellan Region
and Cape Horn Archipelago since 1998. In order to create baseline information for its cultivation and repopulation, we studied
the effects of agricultural fertilizers on growth of G. skottsbergii early developmental stages. The culture media utilized were: a) seawater + Bayfoland, b) seawater + Superphosphate, c) seawater
+ Urea, d) seawater + Provasoli and e) seawater as a control. The culture conditions were: a) 12L:12D photoperiod; b) temperature
8 ± 1°C and c) irradiance at 45 μmol photons m−2 s−1. After 60 days, higher relative growth rates between treatments were observed; the treatments that included Bayfoland and
Provasoli showed greater growth (382 ± 55 and 378 ± 50 μm, respectively,) compared to Superphosphate (88 ± 16 μm), control
(78 ± 10 μm) and Urea (70 ± 11 μm) treatments, after 81 days. The Urea treatment and the control had inhibitory effects on
G. skottsbergii germlings growth and survival, as evidenced by progressive loss of pigmentation and death after 60 days. These results showed
that Bayfoland was an excellent alternative to develop cultures. 相似文献
19.
Sherri M. Jones Timothy A. Jones Roshni Shukla 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(6):631-638
Short-latency vestibular-evoked potentials to pulsed linear acceleration were characterized in the quail. Responses occurred
within 8 ms following the onset of stimuli and were composed of a series of positive and negative peaks. The latencies and
amplitudes of the first four peaks were quantitatively characterized. Mean latencies at 1.0 g ms−1 ranged from 1265 ± 208 μs (P1, N = 18) to 4802 ± 441 μs (N4, N = 13). Amplitudes ranged from 3.72 ± 1.51 μV (P1/N1, N = 18) to 1.49 ± 0.77 μV (P3/N3, N = 16). Latency-intensity (LI) slopes ranged from −38.7 ± 7.3 μs dB−1 (P1, N = 18) to −71.6 ± 21.9 μs dB−1 (N3, N = 15) and amplitude-intensity (AI) slopes ranged from 0.20 ± 0.08 μV dB−1 (P1/N1, N = 18) to 0.07 ± 0.04 μV dB−1 (P3/N3, N = 11). The mean response threshold across all animals was −21.83 ± 3.34 dB re: 1.0 g ms−1 (N = 18). Responses remained after cochlear extirpation showing that they could not depend critically on cochlear activity.
Responses were eliminated by destruction of the vestibular end organs, thus showing that responses depended critically and
specifically on the vestibular system. The results demonstrate that the responses are vestibular and the findings provide
a scientific basis for using vestibular responses to evaluate vestibular function through ontogeny and senescence in the quail.
Accepted: 18 January 1997 相似文献
20.
White rot fungi are a promising option to treat recalcitrant organic molecules, such as lignin, polycyclic aromatic hydrocarbons,
and textile dyes, because of the lignin-modifying enzymes (LMEs) they secrete. Because knowledge of the kinetic parameters
is important to better design and operate bioreactors to cultivate these fungi for degradation and/or to produce LME(s), these
parameters were determined using Trametes versicolor ATCC 20869 (ATCC, American Type Culture Collection) in a magnetic stir bar reactor. A complete set of kinetic data has not
been previously published for this culture. Higher than previously reported growth rates with high laccase production of up
to 1,385 U l−1 occurred during growth without or glucose limitation. The maximum specific growth rate averaged 0.94 ± 0.23 day−1, whereas the maximum specific substrate consumption rates for glucose and ammonium were 3.37 ± 1.16 and 0.15 ± 0.04 day−1, respectively. The maximum specific oxygen consumption rate was 1.63 ± 0.36 day−1. 相似文献