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1.
Masato Moteki Naho Horimoto Riou Nagaiwa Kazuo Amakasu Takashi Ishimaru Yukuya Yamaguchi 《Polar Biology》2009,32(10):1461-1472
The horizontal and vertical distributions of fish were examined off Lützow-Holm Bay in the Indian Ocean sector of the Southern
Ocean during midnight sun in January 2005. Fish were sampled from six discrete depth layers (0–2,000 m). The most abundant
fish in layers from the surface to 200 m were larval stages of Electrona antarctica and Notolepis coatsi. In layers from 200 to 2,000 m, fish assemblages were relatively uniform among all stations and were dominated by E. antarctica (juvenile–subadult), Cyclothone microdon, and Bathylagus antarcticus. Cluster analysis revealed three epipelagic communities related to water temperature and salinity. An ontogenetic habitat
shift to deeper layers was apparent for E. antarctica, N. coatsi, and B. antarcticus. Preferences for warm waters were observed in E. antarctica (larvae) and N. coatsi (preflexion to flexion larvae), although they were distributed across a broad range of temperature and salinity in epipelagic
zones. 相似文献
2.
Donna Roberts William R. Howard Andrew D. Moy Jason L. Roberts Thomas W. Trull Stephen G. Bray Russell R. Hopcroft 《Polar Biology》2011,34(11):1739-1750
Anthropogenic inputs of CO2 are altering ocean chemistry and may alter the role of marine calcifiers in ocean ecosystems. Laboratory research and ocean
models suggest calcifiers in polar waters are especially at risk, particularly pteropods: pelagic aragonite-shelled molluscs.
However, baseline data for natural populations of pteropods are limited, especially for polar and sub-polar waters. In order
to establish baseline data on diversity, preservation state and shell flux of in situ populations of Sub-Antarctic Southern
Ocean pteropods, we deployed sediment traps above (1,000 m) and below (2,000 m) the aragonite saturation horizon (ASH) (currently
at 1,200 m) from 1997 to 2006 at 47°S, 142°E. We identified seven pteropod taxa. We applied a shell opacity index to each
shell collected and found 50% of shells collected above the ASH to be in pristine condition but only 3% of the shells collected
below the ASH showed such a high degree of preservation. We estimated pteropod shell mass fluxes for the region (0.17–4.99 mg m−2 day−1), and we identified significant reductions in shell flux for Limacina helicina antarctica forma rangi and Clio recurva to the trap series above the ASH and for Limacina helicina antarctica forma rangi and Limacina helicina antarctica forma antarctica to the trap series below the ASH over the interval 1997–2006. Our data establish a temporal and vertical snapshot of the
current Sub-Antarctic pelagic pteropod community and provide a baseline against which to monitor Southern Ocean pteropods
responses, if any, to changing ocean conditions projected for the region in the coming decades. 相似文献
3.
Martin A. Collins Jose C. Xavier Nadine M. Johnston Anthony W. North Peter Enderlein Geraint A. Tarling Claire M. Waluda Elizabeth J. Hawker Nathan J. Cunningham 《Polar Biology》2008,31(7):837-851
The mesopelagic fish community of the northern Scotia Sea was investigated during the austral autumn using multi-frequency
acoustics, opening and closing nets and pelagic trawls fished from the surface to 1,000 m. The Family Myctophidae (15 species
in 5 genera) dominated the ichthyofauna, with larval notothenids caught over the South Georgia shelf and bathylagids and stomiids
abundant in deeper hauls. The biomass of myctophids was estimated to be 2.93 g wet weight 1,000 m−3, with Electrona carlsbergi, E. antarctica, Protomyctophum bolini, P. choriodon, Gymnoscopelus braueri, G. fraseri, G. nicholsi and Krefftichthys anderssoni, being the most abundant species. Analysis of community structure indicated a high level of depth stratification within the
myctophids, with evidence of diurnal vertical migration in some, but not all, species. Length-frequencies of G. braueri, G. nicholsi, E. antarctica and K. anderssoni were multimodal, suggesting that all life stages may be present in the northern Scotia Sea. In contrast, P. choriodon, P. bolini, G. fraseri and E. carlsbergi had unimodal distributions despite having multi-year lifecycles, indicating that they probably migrate into the region from
warmer areas to the north. 相似文献
4.
The content of proteins, lipids and carbohydrates and the calorific contents in six Antarctic and three south Chilean brown algae were determined. These constitute the first reports of chemical composition in the endemic Antarctic species Cystosphaera jacquinotii, Phaeurus antarcticus and Desmarestia antarctica. There were no marked differences in total energy levels between Antarctic and cold-temperate species (values between 10.6 and 13 kJ g–1 dry weight). However, species such as Adenocystis utricularis showed significantly higher ash-free energy (26.3 kJ), which is explained in terms of morpho-functional differentiation. Ascoseira mirabilis and Phaeurus antarcticus showed high total lipids (2.1–2.2% dry weight) and soluble carbohydrates (5.9 and 3.4% dry weight). In general, algae from Chile had similar energy levels and no obvious differences in organic content could be found. 相似文献
5.
The lipid content, fatty acid composition and calorific value of seven species of mesopelagic deep-sea fish of the family Myctophidae and the mackerel icefish, Champsocephalus gunnari, important in the diet of Southern Ocean marine predators, are presented. Fish were sampled at the Kerguelen Plateau (KP) and Macquarie Ridge (MR) in the Indian and Pacific sectors of the Southern Ocean respectively, to examine geographic variation in lipid compositon. All species of myctophid from KP and Electrona antarctica from MR were high in lipid content (6-18% wet mass), particularly Gymnoscopelus nicholsi (18%) and E. antarctica (15%). The mackerel icefish, and G. fraseri and Protomyctophum tenisoni from MR were generally lower in lipid content (3-5%) and varied significantly in fatty acid composition from KP species. KP myctophids were high in calorific content (9.3 kJ g-1 wet mass) when compared with icefish (5.4 kJ g-1 wet mass) and other published values for prey items of marine predators such as squid (1.7-4.5 kJ g-1). KP myctophids were distinguished from each other and from C. gunnari and MR specimens by cluster and discriminant function analysis using six fatty acids (16:0, 18:1̩, 20:1̩, 22:1Ὃ, 20:5̣, 22:6̣). Findings presented here highlight trophic links between high-latitude fish and their prey and emphasise the importance of myctophids as a significant energy source for marine predators foraging in the Polar Frontal Zone. 相似文献
6.
C. M. Todd 《Polar Biology》1997,18(3):166-171
The influence of feeding state on cold-adapted metabolism was investigated in the adults of two carabid beetles, Trechisibus antarcticus and Oopterus soledadinus (Coleoptera: Carabidae), which have been introduced to sub-Antarctic South Georgia. The metabolic rates in both fed and starved
O. soledadinus and T. antarcticus were determined at eight temperatures ranging from 0 to 35°C, using a Servomex 570A oxygen analyser. There was no significant
difference in the metabolic rates between the fed and starved animals of each species. In T. antarcticus this ranged from 0.28 to 3.84 ml O2 g−1 h−1, and in O. soledadinus from 0.19 to 2.80 ml O2 g−1 h−1 at 0 and 35°C, respectively. In each of the four experimental groups there was a strong positive correlation between metabolic
rate and temperature, with the highest increase occurring between 0 and 5°C. In contrast, the metabolic rate was significantly
negatively correlated with initial live weight of the beetles at most temperatures. The results are discussed comparatively
with other species and against a background of the ecology of the two carabids at South Georgia.
Received: 26 August 1996 / Accepted: 3 February 1997 相似文献
7.
Voigt CC Kelm DH Visser GH 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2006,176(3):213-222
Recently, it was argued that extrinsic factors, such as high foraging costs, lead to elevated field metabolic rates (FMR).
We tested this suggestion by comparing the FMR of nectar-feeding and fruit-eating bats. We hypothesized that the foraging
effort per energy reward is higher for nectar-feeding mammals than for fruit-eating mammals, since energy rewards at flowering
plants are smaller than those at fruiting plants. Using the doubly labelled water method, we measured the FMR of nectar-feeding
Glossophaga commissarisi and fruit-eating Carollia brevicauda, which coexisted in the same rainforest habitat and shared the same daytime roosts. Mass-specific FMR of G. commissarisi exceeded that of C. brevicauda by a factor of almost two: 5.3±0.6 kJ g−1 day−1 for G. commissarisi and 2.8±0.4 kJ g−1 day−1 for C. brevicauda. Since nectar-feeding bats imbibe nectar droplets of only 193 J energy content during each flower visit, a G. commissarisi bat has to perform several 100 flower visits per night to meet its energy requirement. The fruit-eating C. brevicauda, on the other hand, needs to harvest only 3–12 Piper infructescenses per night, as the energy reward per Piper equals ca. 6–30 kJ. We argue that the flowering and fruiting plants exert different selective forces on the foraging behaviour
and energetics of pollinators and the seed dispersers, respectively. A comparison between nectar-feeding and non-nectar-feeding
species in various vertebrate taxa demonstrates that pollinators have elevated FMRs. 相似文献
8.
Adaptation and acclimation of growth and photosynthesis of five Antarctic red algae to low temperatures 总被引:2,自引:0,他引:2
Temperature requirements for growth, photosynthesis and dark respiration were determined for five Antarctic red algal species.
After acclimation, the stenothermal species Gigartina skottsbergii and Ballia callitricha grew at 0 or up to 5 °C, respectively; the eurythermal species Kallymenia antarctica, Gymnogongrus antarcticus and Phyllophora ahnfeltioides grew up to 10 °C. The temperature optima of photosynthesis were between 10 and 15 °C in the stenothermal species and between
15 and 25 °C in the eurythermal species, irrespective of the growth temperature. This shows that the temperature optima for
photosynthesis are located well below the optima from species of other biogeographical regions, even from the Arctic. Respiratory
rates rose with increasing temperatures. In contrast to photosynthesis, no temperature optimum was evident between 0 and 25 °C.
Partial acclimation of photosynthetic capacity to growth temperature was found in two species. B. callitricha and Gymnogongrus antarcticus acclimate to 0 °C, and 5 and 0 °C, respectively. But acclimation did in no case lead to an overall shift in the temperature
optimum of photosynthesis. B. callitricha and Gymnogongrus antarcticus showed acclimation of respiration to 5 °C, and P. ahnfeltioides to 5 and 10 °C, resulting in a temperature independence of respiration when measured at growth temperature. With respect
to the acclimation potential of the species, no distinction can be made between the stenothermal versus the eurythermal group.
(Net)photosynthetic capacity:respiration (P:R) ratios showed in all species highest values at 0 °C and decreased continuously to values lower than 1.0 at 25 °C. In turn,
the low P:R ratios at higher temperatures are assumed to determine the upper temperature growth limit of the studied species. Estimated
daily carbon balance reached values between 4.1 and 30.7 mg C g−1 FW day−1 at 0 °C, 16:8 h light/dark cycle, 12–40 μmol m−2 s−1.
Received: 4 November 1999 / Accepted: 7 March 2000 相似文献
9.
The summer Phaeocystis antarctica bloom increases under-ice phytoplankton biomass in McMurdo Sound, Antarctica. The magnitude of mesozooplankton grazing on
this bloom is unknown, and determines whether this production is available to the pelagic food web. We measured mesozooplankton
abundance and body content of dimethylsulfoniopropionate (DMSP) during the McMurdo Sound austral summer (2006 and 2006–2007).
Abundance varied from 20 to 4,500 ind. m−3 (biomass 0.02–274.0 mg C m−3), with peaks in mid-December and late-January/February. Abundance was higher but total zooplankton biomass lower in our study
compared to previous reports. Copepods and the pteropod Limacina helicina dominated the zooplankton in both abundance and biomass. DMSP was detected in all zooplankton groups, with highest concentrations
in copepod nauplii and L. helicina (95 and 54 nmol mg−1 body C, respectively). Experiments suggested that L. helicina obtains DMSP by directly grazing on P. antarctica, which often accumulates to high biomass under the summer sea ice in McMurdo Sound. 相似文献
10.
Interpretation of photosynthetic pigment data using iterative programs such as CHEMTAX are widely used to examine algal community
structure in the surface ocean. The accuracy of such programs relies on understanding the effects of environmental parameters
on the pigment composition of taxonomically diverse algal groups. Phaeocystis antarctica is an important contributor to total autotrophic production and the biogeochemical cycling of carbon and sulfur in the Southern
Ocean. Here we report the results of a laboratory culture experiment in which we examined the effects of ambient dissolved
iron concentration on the pigment composition of colonial P. antarctica, using a new P. antarctica strain isolated from the southern Ross Sea in December 2003. Low-iron (<0.2 nM dissolved Fe) filtered Ross Sea seawater was
used to prepare the growth media, thus allowing sub-nanomolar iron additions without the use of EDTA to control dissolved
iron concentrations. The experiment was conducted at relatively low irradiance (∼20 μE m−2 s−1), with P. antarctica primarily present in the colonial form—conditions that are typical of the southern Ross Sea during austral spring. Relative
to the iron-limited control treatments (0.22 nM dissolved Fe), iron addition mediated a decrease in the ratio of 19′-hexanoyloxyfucoxanthin
to chlorophyll a, and an increase in the ratio of fucoxanthin to chlorophyll a. Our results also suggest that the ratio of 19′-hexanoyloxyfucoxanthin to chlorophyll c3 (Hex:Chl c3 ratio) may be a characteristic physiological indicator for the iron-nutritional status of colonial P. antarctica, with higher Hex:Chl c3 ratios (>3) indicative of Fe stress. We also observed that the ratio of fucoxanthin to 19′-hexanoyloxyfucoxanthin (Fuco:Hex
ratio) was highly correlated (r
2 = 0.82) with initial dissolved Fe concentration, with Fuco:Hex ratios <0.05 measured under iron-limited conditions (dissolved
Fe <0.45 nM). Our results corroborate and extend the results of previous experimental studies, and, combined with pigment
measurements from the southern Ross Sea, are consistent with the hypothesis that the interconversion of fucoxanthin and 19′-hexanoyloxyfucoxanthin
by colonial P. antarctica is used as a photo-protective or light-harvesting mechanism, according to the availability of dissolved iron. 相似文献
11.
Aluminum in lake water and in the organs of the fish Tribolodon hakonensis was investigated in Lake Usoriko (pH 3.6), Lake Inawashiroko (pH 5.0), and the Tenryu River (pH 7.7). The concentration of
total soluble aluminum in the water was 0.51 mg l−1 in Usoriko, 0.05 mg l−1 in Inawashiroko, and less than 0.01 mg l−1 in the Tenryu. The chemical forms of soluble aluminum in the acid water were characterized as Al3+, AlL2+, and AlL≦1+. More than 90% of soluble aluminum in the water of Usoriko was Al3+, whereas AlL2+ was dominant in the water of Inawashiroko. The aluminum concentration in the organs of T. hakonensis in Usoriko was 42 μg g−1 wet weight in gills, 4.2 μg g−1 in muscle, 6.9 μg g−1 in bone, 12.7 μg g−1 in liver, 6.0 μg g−1 in kidney, and 6.0 μg g−1 in intestine, indicating accumulation of aluminum in the gills. The aluminum concentration in the organs of T. hakonensis living in Inawashiroko was approximately the same, in spite of the difference in water chemistry of the two acid lakes, especially
for pH and aluminum. This suggests that aluminum accumulation might be controlled in the fish living in the acid lakes. In
contrast, the aluminum concentration in the gills of T. hakonensis from the Tenryu was 2 μg g−1.
Received: May 20, 1999 / Accepted: December 10, 1999 相似文献
12.
M.I. Rajoka Khalil-ur- Rehman Tehmina Tabish M.A. Zia 《World journal of microbiology & biotechnology》2006,22(3):289-291
Purified uricase from a caprine kidney, possessed K
m
and V
max values of 1.1 mg ml−1 and 3512 IU (mg protein)−1 for uric acid hydrolysis, respectively. The optimum temperature and pH for catalytic activity were 40 °C and 8.5, respectively.
The activation energy for formation of ES complex was 13.6 kJ mol−1. Enthalpy (ΔH*), entropy of activation (ΔS*) and Gibbs free energy demand of uricase inactivation were 62.8 kJ mol−1, −102 J mol−1 K−1 and 104.3 kJ mol−1, respectively. Gibbs free enrgy demand for substrate binding and transition state stabilization were also determined which
were comparable with those for themostable enzymes. 相似文献
13.
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
14.
Arribére MA Ribeiro Guevara S Bubach DF Arcagni M Vigliano PH 《Biological trace element research》2008,122(1):42-63
A survey of mercury (Hg) and selenium (Se) contents was performed in fish collected from lakes located in two National Parks
of the northern patagonian Andean range. Two native species, catfish (Diplomystes viedmensis) and creole perch (Percichthys trucha), and three introduced species, brown trout (Salmo trutta), rainbow trout (Oncorhynchus mykiss), and brook trout (Salvelinus fontinalis), were caught from lakes Nahuel Huapi, Moreno, Traful, Espejo Chico, and Guillelmo belonging to Nahuel Huapi National Park
and from lakes Futalaufquen and Rivadavia, Los Alerces National Park. In lake Moreno, fish diet items were analyzed and rainbow
trout grown in a farm. Hg and Se were measured in muscle and liver tissues by instrumental neutron activation analysis. The
average concentrations in muscle of Hg for all species, ages, and lakes are between 0.4 to 1.0 μg g−1 dry weight (DW) with a few fish, mainly native, exceeding the United States Environmental Protection Agency health advisory
for freshwater fish limited consumption, and from 0.8 to 1.5 μg g−1 DW for Se. Average concentrations in liver of Hg in all species range from 0.4 to 0.9 μg g−1 DW. Brown trout, the top predator in these lakes, showed the lowest average Hg burden in both tissues. Se concentrations
in the liver of brown and rainbow trout, up to 279 μg g−1 DW, are higher than those expected for nearly pristine lakes, exceeding 20 μg g−1 DW, the threshold concentration associated with Se toxicity. These species show lower Hg contents in muscle, suggesting a
possible detoxification of Hg by a Se-rich diet. Creole perch and velvet catfish livers have lower Se concentrations, with
a narrower span of values (2.3 to 8.5 μg g−1 and 3.3 to 5.5 μg g−1 DW respectively). 相似文献
15.
Gustavo Hernández-Carmona Silvia Carrillo-Domínguez Dora Luz Arvizu-Higuera Y. Elizabeth Rodríguez-Montesinos J. Iván Murillo-Álvarez Mauricio Muñoz-Ochoa Rosa María Castillo-Domínguez 《Journal of applied phycology》2009,21(5):607-616
The brown alga Eisenia arborea is the second most abundant brown alga along the western coast of the Baja California Peninsula of Mexico. Samples of E. arborea were collected in Bahía Asunción, BCS, over 10 months. Chemical composition was analyzed from dried alga (%, dw): moisture
(10.34%), protein (9.44%), ash (24.77%), lipids (0.60%), fiber (5.22%), and carbohydrates (49%). Gross energy was 9.8 kJ g−1. Seven minerals were analyzed and the four most abundant were K, Na, Mg, and Ca, ranging from 907 to 7,946 mg.100 g−1. The concentrations of six vitamin levels were also determined: A, C, E, D3, B2, and B1. Seventeen amino acids were analyzed and the most abundant were glutamic acid, aspartic acid, and leucine. Total fatty acids
ranged from 21 to 65 mg.100 g−1 (dw). Individual concentrations were also determined for arachidonic acid, alpha linolenic acid, linoleic acid, eicosapentaenoic
acid, and docosahexaenoic acid. Saponins, cyanogenic glycosides, and alkaloids were not detected. Our results suggest that
E. arborea is a good candidate to be tested as supplement food for animals, including humans. It contains essential amino acids, is
low in lipids and fiber, and could be a source of vitamins and minerals. 相似文献
16.
Aude Lochet Régine Maury-Brachet Claire Poirier Javier Tomás Michel Lahaye Miran Aprahamian Eric Rochard 《Hydrobiologia》2008,602(1):99-109
Mercury concentration [Hg] was assessed in 20 adult Allis shad Alosa alosa (54–59 cm) and 20 adult Twaite shad Alosa fallax (36–44 cm) collected during their spawning migration in the Dordogne and the Garonne rivers (France). [Hg] was measured in
the gills, dorsal muscle, liver and kidney. Twaite shad exhibited higher [Hg] than Allis shad. Median [Hg] values were [Hg]Gills = 0.33 μg g−1 (dw), [Hg]Muscle = 1.22 μg g−1, [Hg]Liver = 1.99 μg g−1, [Hg]Kidney = 1.93 μg g−1 for Twaite shad and [Hg]Gills = 0.06 μg g−1, [Hg]Muscle = 0.20 μg g−1, [Hg]Liver = 1.18 μg g−1, [Hg]Kidney = 1.08 μg g−1 for Allis shad. In order to understand such differences, we investigated some life history traits of the two species: migratory
history, age (3–6 years), size at age (an expression of growth) and the number of spawning events (0–2 events). The difference
in estuarine residence time between the juveniles of both species, which was assumed to influence [Hg], was investigated using
otolith Sr:Ca ratio. The microchemical analysis revealed a significant difference in the residence time of juveniles in the
estuary (medians are 21 d and 10 d for Twaite shad and Allis shad, respectively) but this residence time seems too short to
influence [Hg] (Allis shad: r
spearman < 0.128; Twaite shad: r
spearman < −0.340). As both species show the same age structure, the influence of age on [Hg] was negligible. The literature shows
that the differences in growth and in the number of spawning events reported in our study are in favour of a higher [Hg] for
Twaite shad than for Allis shad. Although trophic status was not investigated here, the literature reveals that it is another
factor that could produce higher [Hg] in Twaite shad, since its diet includes higher trophic levels than Allis shad.
Guest editors: S. Dufour, E. Prévost, E. Rochard & P. Williot
Fish and diadromy in Europe (ecology, management, conservation) 相似文献
17.
Zhibiao Xu Xiaojun Yan Luqing Pei Qijun Luo Jilin Xu 《Journal of applied phycology》2008,20(3):237-243
Changes in the composition of fatty acids and sterols of Pavlova viridis cultured in an air-lift photobioreactor were studied using gas chromatography-mass spectrometry (GC-MS). The results show
that radical changes in fatty acid and sterol contents and compositions occurred during growth phase transitions: the total
lipid increased along with the culture age, from 166.4 mg g−1 (late exponential phase) to 232.7 mg g−1 (linear phase), and increased further to be 235.1 mg g−1 in the stationary phase. Polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA), decreased along with
the culture time, PUFAs, and EPA contents maximized in the late exponential phase to become 46.2 mg g−1 and 22.1 mg g−1 respectively; there was no significant change in docosahexaenoic acid (DHA) content during the whole growth phase, although
it reached the peak in the linear phase with 3.5 mg g−1. As for the sterols, two unique sterols with two hydroxyl groups, termed pavlovols, were observed. 4α,24-Dimethylcholestan-3β,4β-diol,
one of the pavlovols, increased almost 2-fold from the late exponential phase (2.5 mg g−1) to the stationary phase (4.3 mg g−1). On the contrary, the contents of stigmasterol and sitosterol decreased with culture age, with the maximum content of 2.4 mg
g−1 and 3.1 mg g−1, both obtained in the late exponential phase, respectively. The results indicate that growth phase control could be used
as a methodology to optimize the total lipid, EPA, PUFA, and sterol contents with the potential for both aquaculture feeds
and nutraceutical applications, especially for further research into unique pavlovols. 相似文献
18.
The vitamin content of microalgae used in aquaculture 总被引:4,自引:0,他引:4
M.R. Brown M. Mular I. Miller C. Farmer C. Trenerry 《Journal of applied phycology》1999,11(3):247-255
The vitamin content in four Australian microalgae, a Nannochloropsis-like sp., Pavlova pinguis, Stichococcus sp. and Tetraselmis
sp., were examined. These were grown under a 12:12 h light:dark regimen (100 μmol photon m−2s−1) and harvested during late-logarithmic phase. Typically, the content showed a two- to three fold range between the species.
When expressed on a dry weight basis, the content of ascorbate ranged from 1.3 to 3.0 mg g−1, β-carotene from 0.37 to 1.05 mg g−1, α-tocopherol from 0.07 to 0.29 mg g−1, thiamine from 29 to 109 μg g−1, riboflavin from 25 to 50 μg g−1, total folates from 17 to 24 μg g−1, pyridoxine from 3.6 to 17 μg g−1, cobalamin from 1.70 to 1.95 μg g−1 and biotin from 1.1 to 1.9 μg g−1. Retinol was detected only in Tetraselmis sp. (2.2 μg g−1); any vitamins D2 or D3 were below the detection limit (≤0.45 μg g−1). Nannochloropsis sp. was also grown under a 24:0 h light:dark light cycle and harvested at stationary phase. The content
of most vitamins in Nannochloropsis sp. cultures differed significantly, and the degree of variation was similar to that observed
between the four species grown under 12:12 h light:dark regimen (100 μmol photon m−2s−1) and harvested during late-logarithmic phase. Thiamine content was also examined in six non-Australian strains commonly used
in aquaculture, Chaetoceros muelleri, Thalassiosira pseudonana, Nannochloris atomus, Nannochloropsis oculata, Isochrysis sp.
(T.ISO) and Pavlova lutheri. Values (average 61 μg g−1; range 40 to 82) were similar to those in the Australian strains (average 61 μg g−1; range 29 to 109) and increased during stationary phase (average 94 μg g−1; 38 to 131). Comparison of the data with the known nutritional requirements for marine fish species and prawns suggests that
the microalgae should provide excess or adequate levels of the vitamins for aquaculture food chains. The data may be used
to guide the content of vitamins included in micro-diets developed as replacements for live diets.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
Nototheniid and myctophid fish are primary prey for marine piscivores, yet little is known about their nutritional value.
In this study, we characterized the proximate composition [PC: water, fat (neutral lipids), crude protein (CP) and ash] and
energy density (ED; kJ g−1) of fifteen fish species from McMurdo Sound and the Ross Sea, Antarctica. We assayed the entire fish for all species except
for the large Antarctic toothfish, Dissostichus mawsoni (muscle tissue only). On a wet mass basis (WM), fish were variable in composition: moisture content ranged from 64.9 to 87.3%
WM, fat from 0.5 to 17.4% WM, CP from 7.7 to 16.7% WM, ash from 11.2 to 21.0% FFDM (fat-free dry mass), and ED from 2.9 to
10.3 kJ g−1. Myctophids and pelagic nototheniids such as Pleuragramma antarcticum and D. mawsoni were high in fat content (7–17% WM), while a bathylagid and benthic nototheniids including most Trematomus spp. and Lepidonotothen squamifrons were low in fat (0.5–4% WM). The epibenthic Trematomus species (T. eulepidotus and T. lepidorhinus) were intermediate. Energy density tracked fat content, with highest values in myctophids and pelagic nototheniids. The variation
in nutrient and energy density confirms that prey composition must be taken into account when modelling energy and nutrient
fluxes within the Antarctic ecosystem. Further analyses of prey collected over a number of different locations and seasons
are needed in order to determine how the nutritional value of certain species might affect annual or decadal variation in
reproductive success or population size of top predators. 相似文献
20.
Marine foraging and annual fish consumption of a south polar skua population in the maritime Antarctic 总被引:1,自引:1,他引:0
Pelagic fish are an important component of Antarctic food webs but few quantitative data exist on energy transfer from fish
to seabirds for the Seasonal Pack-ice Zone. We studied a local population of south polar, skuas Catharacta maccormicki during a whole breeding cycle and estimated its entire annual food consumption. The lengths of foraging trips suggested that
skuas foraged in an area of 817 km2 of coastal waters around the breeding site. Their fish prey consisted almost entirely of two pelagic species, Electrona antarctica and Pleuragramma antarcticum, with individual mean energy contents of 28.62 and 30.26 kJ/g dry weight and body masses of 4.6 and 10.9 g, respectively.
Total energy budget estimates of the entire south polar skua population resulted in 3 and 5 tons of pelagic fish caught per
season (1994 and 2001, respectively), wherein a single breeding pair raising two chicks requires approximately 115.7 kg E. antarctica and 24.4 kg P. antarcticum. Our study suggests that the pelagic fish in coastal areas are highly important for surface feeding seabirds in the maritime
Antarctic. 相似文献