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1.
To determine the sources and sinks of atmospherically deposited Pb at a forested watershed (Plastic Lake) in central Ontario,
Canada, Pb pools and fluxes through upland, wetland and lake compartments were measured during 2002/2003 and compared with
previous measurements taken between 1989 and 1991. In 2002/2003, annual bulk deposition of Pb was 0.49 mg m−2 compared with 1.90–1.30 mg m−2 in 1989–1991. Annual Pb concentrations in stream water draining the upland part of the catchment were very low (0.04 μg l−1) and were approximately half those measured in 1989–1991 (0.11–0.08 μg l−1). Leaching losses in stream water were small and mass balance estimates indicate almost complete retention (>95%) of atmospherically
deposited Pb in upland soils. In contrast, annual Pb concentrations in stream water draining a wetland were between 0.38 and
0.77 μg l−1, with the highest concentration occurring in 2002/2003 and mass balance calculations indicate that the wetland is a net source
of Pb in all measured years. Lead concentrations in the lake outflow were low and the average Pb concentration measured in
2002/2003 (0.09 μg l−1) was approximately half the value recorded in 1989–1991 (0.19 μg l−1 both years). Annual mass balance estimates indicate that the lake retained between 2.47 mg m−2 (1989/1990) and 1.42 mg m−2 (2002/2003) and that in 2002/2003 68% of the Pb input to the lake is derived from the terrestrial catchment. These estimates
are higher than sediment core records, which indicate around 18 mg m−2 Pb was retained in sediment during the 1990s. Nevertheless, Pb concentrations decrease with sediment depth and 206Pb/207Pb concentrations increase with depth, a pattern also observed in mineral soils that reflects the substantial contribution
of anthropogenic Pb to the watershed. Lead isotope data from soil and sediment indicate a recent anthropogenic Pb signal (206Pb/207Pb ∼ 1.185) in upper soils and sediments and an older anthropogenic signal (206Pb/207Pb ∼ 1.20) in deeper soil and sediment. Lead isotope data in sediment and vegetation indicate that practically all the Pb
cycled in the forest at Plastic Lake is anthropogenic in origin. 相似文献
2.
A previously derived method (the tidal length—mean spring tidal range, TL-MSTR diagram) is used to predict the estuarine turbidity
maximum (ETM) concentration and the residence time of the Thames Estuary. The predicted and observed residence time is 2 months.
The predicted, depth-averaged ETM is 2.5 g l−1 of suspended particulate matter (SPM) at spring tides, which is much higher than that observed from surface sampling (<0.5 g l−1) and that simulated by recent models (approx. 0.6 g l−1), but is consistent with spring-tide concentrations measured throughout the water column over a tidal cycle. The observed
locations of the surface 1-isohaline and 5-isohaline exhibit strong relationships with the logarithm of freshwater runoff.
The observed ETM exhibits statistically significant relationships both with tidal range and the logarithm of runoff, and is
generally located between the Millennium Dome and the Woolwich Reach. The apparent over-prediction of SPM afforded by the
TL-MSTR diagram is unsurprising considering the removal of fine sediment by dredging and the removal of fine-sediment storage
areas by embanking. 相似文献
3.
The results of analyses conducted to determine contents of Cd(II) and Pb(II) in mushrooms of mycorrhizal fungi and selected
parts of birches growing in an industrial desert surrounding a nonferrous works are presented in this study. The fruiting
bodies of fungi accumulated several times higher contents (up to 80 μg g−1 dry weight) of Cd(II) compared to those found in the soil (20 μg g−1 dry weight). In contrast, the mushroom contents of Pb(II) were only slightly increased (up to 895 μg g−1 dry weight) than those present in the soil (500 μg g−1 dry weight). However, fivefold higher concentrations of the metals were found in the mycorrhizal roots. Comparing the distribution
of the metals analysed, the protective role of the ectomycorrhizae in relation to the host tree was indicated. Mycorrhizal
fungi persistently fixed heavy metals, forming an efficient biological barrier that reduced movement of the metals in birch
tissues. 相似文献
4.
Summary The sensitivity of the mineralization of nitrogen by a range of soils contaminated with heavy metals (up to 340 μg Cd g−1, 7500 μg Pb g−1 and 34000 μg Zn g−1) to the addition of heavy metals in solution were studied using pot incubations (ammonification) and a soil perfusion technique
(nitrification). The ammonification of peptone showed little correlation between treatments with Cd, Zn (1000 and 5000 μg
g−1) and Pb (10000 and 20000 μg g−1) and origin of the soil. Nitrification was considerably more sensitive to heavy metals than ammonification. All the soils
had active, often large, populations of ammonifying and nitrifying organisms which showed substantial similarities between
the soils. The rate of nitrifying activity (NO3−N production) was logrithmic in most cases. The presence of tolerant populations of nitrifying organisms in the contaminated
soils was demonstrated. Tolerance was also eventually acquired after a longer lag phase, by the non-contaminated soil populations
although the rate of activity was often reduced. Metals added in solution were adsorbed by the soil within 4 hours. Differences
in toxicity between metal salts (chlorides, sulphates and acetate) were attributed to the amount left in solution. However,
in many instances, acetate was found to stimulate all the stages in the mineralisation of nitrogen. 相似文献
5.
The Status and Characteristics of Eutrophication in the Yangtze River (Changjiang) Estuary and the Adjacent East China Sea, China 总被引:19,自引:0,他引:19
Eutrophication has become increasingly serious and noxious algal blooms have been of more frequent occurrence in the Yangtze
River Estuary and in the adjacent East China Sea. In 2003 and 2004, four cruises were undertaken in three zones in the estuary
and in the adjacent sea to investigate nitrate (NO3–N), ammonium (NH4–N), nitrite (NO2–N), soluble reactive phosphorus (SRP), dissolved reactive silica (DRSi), dissolved oxygen (DO), phytoplankton chlorophyll
a (Chl a) and suspended particulate matter (SPM). The highest concentrations of DIN (NO3–N+NH4–N+NO2–N), SRP and DRSi were 131.6, 1.2 and 155.6 μM, respectively. The maximum Chl a concentration was 19.5 mg m−3 in spring. An analysis of historical and recent data revealed that in the last 40 years, nitrate and SRP concentrations increased
from 11 to 97 μM and from 0.4 to 0.95 μM, respectively. From 1963 to 2004, N:P ratios also increased from 30–40 up to 150. In parallel with the N and P enrichment,
a significant increase of Chl a was detected, Chl a maximum being 20 mg m−3, nearly four times higher than in the 1980s. In 2004, the mean DO concentration in bottom waters was 4.35 mg l−1, much lower than in the 1980s. In comparison with other estuaries, the Yangtze River Estuary was characterized by high DIN
and DRSi concentrations, with low SRP concentrations. Despite the higher nutrient concentrations, Chl a concentrations were lower in the inner estuary (Zones 1 and 2) than in the adjacent sea (Zone 3). Based on nutrient availability,
SPM and hydrodynamics, we assumed that in Zones 1 and 2 phytoplankton growth was suppressed by high turbidity, large tidal
amplitude and short residence time. Furthermore, in Zone 3 water stratification was also an important factor that resulted
in a greater phytoplankton biomass and lower DO concentrations. Due to hydrodynamics and turbidity, the open sea was unexpectedly
more sensitive to nutrient enrichment and related eutrophication processes. 相似文献
6.
Three post-emergence herbicides (2,4-D, picloram and glyphosate) were applied to samples of an Alberta agricultural soil at
concentrations of 0, 2, 20, and 200 μg g−1. The effects of these chemicals on certain microbial variables was monitored over 27 days. All herbicides caused enhancement
of basal respiration but only for 9 days following application, and only for concentrations of 200 μg g−1. Substrate-induced respiration was temporarily depressed by 200 μg g−1 picloram and 2,4-D, and briefly enhanced by 200 μg g−1 glyphosate. It is concluded that because changes in microbial variables only occurred at herbicide concentrations of much
higher than that which occurs following field application, the side-effects of these chemicals is probably of little ecological
significance. 相似文献
7.
The side effects of glyphosate on the soil microflora were monitored by applying a range of glyphosate concentrations (0,
2, 20, and 200 μg g−1 herbicide) to incubated soil samples, and following changes in various microbial groups over 27 days. Bacterial propagule
numbers were temporarily enhanced by 20 μg g−1 and 200 μg g−1 glyphosate, while actinomycete and fungal propagule numbers were unaffected by glyphosate. The frequency of three fungal
species on organic particles in soil was temporarily enhanced by 200 μg g−1 glyphosate, while one was inhibited. One species was temporily enhanced on mineral particles. However, many of these fungi
were inhibited by 200 μg g−1 glyphosate in pure culture. There was little agreement between species responses to glyphosate in incubated soil samples
and in pure culture. 相似文献
8.
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
9.
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
10.
Akira Hisanaga Yukuo Eguchi Miyuki Hirata Noburu Ishinishi 《Biological trace element research》1988,16(1):77-85
During the past few centuries, lead production, consumption and emissions, to our total environment have increased remarkably.
We have determined the concentrations of lead in 41 well-preserved ancient and 11 contemporary rib bones of a mature age (40–60
y), with a view to historically evaluating lead exposure in humans. The oldest Japanese bones (1000–300b.c.) were found to contain a mean of 0.58 μg Pb/g dry wt and a mean molar ratio of lead to calcium of 0.6×10−6, compared with 4.7–5.2×10−6 in the bones of the Edo era (1600–1867a.d.) and contemporary residents in Japan. The mean molar ratios of female bones were always higher than those of male bones for
each era. From this fact we may assume that facial cosmetics were one of the main routes of lead exposure among the ancient
Japanese, especially those who lived during the Edo era. 相似文献
11.
A transect of ten profiles was laid out in 20 m intervals on a tidal sand flat approximately 100 m from the east shore of
Sylt until the next tideway was reached. Sediment samples were taken from 0–2 cm depth (oxic layer) and 2–4 cm depth (anoxic
layer). The average content of organic carbon (C) was 2.41 mg g−1 in the oxic layer and 1.86 mg g−1 in the anoxic layer. The organic C content correlated positively with non-biomass C, 0.5M K2SO4 extractable C, total nitrogen (N), cation exchange capacity (CEC), and the textural classes <200 μm, and negatively correlated
with the coarse sand fraction. The average total C:N ratio was 7.0 in the oxic layer and 6.7 in the anoxic layer, indicating
that the C input comes entirely from the microflora. CHCl3-labile C was measured by the fumigation-extraction method and was converted to microbial biomass C (values in brackets).
The average content of CHCl3-labile C was 407 μg g−1 (903 μg g−1) in the oxic layer and 214 μg g−1 (476 μg g−1) in the anoxic layer. CHCl3-labile C did not correlate with CEC and the textural classes <200 μm, indicating that conditions other than the physical
environment determine this fraction (C input, grazing). 相似文献
12.
Extensive beds of benthic, non-calcareous macroalgae are associated with reef formations in oligotrophic coastal waters of
Northeastern Brazil. Large amounts of these algae constantly and naturally detach and decay. Part of them is deposited on
the beach, remains exposed during low tides, and decomposes. Field experiments on decomposition were carried out in a tidal
pool (temperatures fluctuating from 29 to 43°C salinity from 6 to 35 at Ponta do Seixas (Paraiba, Brazil), and laboratory
studies were made in aerobic and anaerobic conditions. High values of NO
3
−
(up to 148.92 μg at 1−1), NO
2
−
(up to 3.14 μg at 1−1) and PO
3
4−
(up to 22.95 μg at 1−1) were released during algal degradation. Nitrogen values were higher in the tidal pool than in aerobic and anaerobic experiments,
as opposed to phosphorus where the opposite phenomenon occurred. The diatom Phaeodactylum tricornutum inoculated in seawater enriched with decomposition products of algae showed intense growth, sometimes similar to that in
complete algal culture medium. Inhibition and death of this diatom was observed in some other experiments. The importance
of drift seaweed as a source of nutrients for the local ecosystem is stressed. 相似文献
13.
Light irradiation had remarkable effects on callus growth of Oldenlandia affinis with an optimum intensity of 35 μmol m−2 s−1. Biosynthesis of kalata B1, the main cyclic peptide in O. affinis, was induced and triggered with rising irradiation intensities. The highest concentration of kalata B1, 0.49 mg g−1 DW characterised by the maximum productivity of 3.88 μg per litre and day was analysed at 120 μmol m−2 s−1, although callus growth was repressed. The light saturation point was established to be 35 μmol m−2 s−1, where kalata B1 productivity was in a similar order (3.41 μg per day) due to the higher growth index. O. affinis suspension cultures were shown to accumulate comparable specific kalata B1 concentrations in a delayed growth associated
production pattern. These were dependent on irradiation intensity (0.16 mg g−1 at 2 μmol m−2 s−1; 0.28 mg g−1 at 35 μmol m−2 s−1). The batch cultivation process resulted in a maximum productivity of 27.30 μg per litre and day with culture doubling times
of 1.16 d−1. Submers operation represented a 8-fold product enhancement compared to callus cultivation. 相似文献
14.
Robert G. Björk Leif Klemedtsson Ulf Molau Jan Harndorf Anja Ödman Reiner Giesler 《Plant and Soil》2007,294(1-2):247-261
The spatial distribution of organic soil nitrogen (N) in alpine tundra was studied along a natural environmental gradient,
covering five plant communities, at the Latnjajaure Field Station, northern Swedish Lapland. The five communities (mesic meadow,
meadow snowbed, dry heath, mesic heath, and heath snowbed) are the dominant types in this region and are differentiated by
soil pH. Net N mineralization, net ammonification, and net nitrification were measured using 40-day laboratory incubations
based on extractable NH4+ and NO3−. Nitrification enzyme activity (NEA), denitrification enzyme activity (DEA), amino acid concentrations, and microbial respiration
were measured for soils from each plant community. The results show that net N mineralization rates were more than three times
higher in the meadow ecosystems (mesic meadow 0.7 μg N g−1 OM day−1 and meadow snowbed 0.6 μg N g−1 OM day−1) than the heath ecosystems (dry heath 0.2 μg N g−1 OM day−1, mesic heath 0.1 μg N g−1 OM day−1 and heath snowbed 0.2 μg N g−1 OM day−1). The net N mineralization rates were negatively correlated to organic soil C/N ratio (r = −0.652, P < 0.001) and positively correlated to soil pH (r = 0.701, P < 0.001). Net nitrification, inorganic N concentrations, and NEA rates also differed between plant communities; the values
for the mesic meadow were at least four times higher than the other plant communities, and the snowbeds formed an intermediate
group. Moreover, the results show a different pattern of distribution for individual amino acids across the plant communities,
with snowbeds tending to have the highest amino acid N concentrations. The differences between plant communities along this
natural gradient also illustrate variations between the dominant mycorrhizal associations in facilitating N capture by the
characteristic functional groups of plants.
Responsible Editor: Bernard Nicolardot 相似文献
15.
Orlita A Sidwa-Gorycka M Malinski E Czerwicka M Kumirska J Golebiowski M Lojkowska E Stepnowski P 《Biotechnology letters》2008,30(3):541-545
Growth of Ruta graveolens shoots was induced when Bacillus sp. cell lysates were added to the culture medium. Elicitation of coumarin by this lysate was also very effective; the concentrations
of isopimpinelin, xanthotoxin and bergapten increased to 610, 2120 and 1460 μg g−1 dry wt, respectively. It also had a significant effect on the production of psoralen and rutamarin (680 and 380 μg g−1 dry wt) and induced the biosynthesis of chalepin, which was not detected in the control sample, up to 47 μg g−1 dry wt With lysates of the Pectobacterium
atrosepticum, their effect on growth was not so significant and had no effect on the induction of coumarin accumulation. But elicitation
with this lysate was much more effective for inducing the production of furoquinolone alkaloids; the concentrations of γ-fagarine,
skimmianine, dictamnine and kokusaginine rose to 99, 680, 172 and 480 μg g−1 dry wt, respectively. 相似文献
16.
Toxic effects of lead (>0.2 mM Pb) were measured in pigeon pea (Cajanus cajan Mill) cv. UPAS grown in sand culture as reduction in growth, yield, and quality of seeds. Leaves containing >38 μg g−1 Pb showed oxidative damage as decrease in chlorophyll content and induction of antioxidants such as carotenoids, proline,
and non-protein thiol contents with enhanced activities of SOD and peroxidase. At excess (>0.2 mM) Pb, accumulation of >1,000 μg
Pb g−1 root tissue was associated with increase in non-protein thiol content. It is concluded that inhibition in root-to-shoot translocation
of Pb and induction in the level of proline, chloroplast pigments, and non-protein thiols and activities of antioxidant enzymes
SOD and peroxidase at <0.2 mM Pb could have protected the pigeon pea plants from the deleterious effects of Pb. However, excess
Pb at >0.2 mM showed a decline in yield, boldness, and quality of seeds despite the expression of an additional band each
of Cu–Zn SOD and peroxidase isoform. The threshold of toxicity and toxicity values in pigeon pea leaves of plants exhibiting
10 and 33% yield depression at 27 days after metal supply were 27 and 56 μg Pb g−1, respectively. 相似文献
17.
G.O. Osuji W.C. Madu C. Braithwaite A. Beyene P.S. Roberts A. Bulgin V. Wright 《Biologia Plantarum》2003,47(2):195-202
The physiological function of glutamate dehydrogenase (GDH) was investigated by treating germinating peanut (Arachis hypogaea L.) seeds with nucleoside triphosphate (NTP) solutions in order to alter the isoenzyme distribution patterns. The free nucleosides
and nucleotides of the GTP-treated peanut were the highest [8.7 μmol g−1(f.m.)], and they decreased through the ATP-treated peanut [5.8 μmol g−1(f.m.)], and CTP-treated peanut [5.5 μmol g−1(f.m.)], to the UTP-treated peanut [4.1 μmol g−1(f.m.)]. The combination of 4 NTPs induced 20 % higher content of Pi [173 nmol g−1(f.m.)] than in the control, but the combined ATP+UTP treatment induced the lowest (93.0 nmol g−1(f.m.)] Pi. The 4 NTP treatment also induced the highest number of GDH isoenzymes (28) followed by the purine NTP treatments
(15 to 20), but the pyrimidine NTP treatments and the combined purine + pyrimidine NTP treatments induced the lowest numbers
(<15) of isoenzymes. The deamination/amination ratios were generally higher in the UTP (0.11), and CTP (0.06) treated peanuts
than in the GTP (0.04), and ATP (0.07) treated peanuts. There were mutual relationships between higher numbers of GDH isoenzymes
present in the GTP-, and ATP-treated peanuts and higher RNA (236.5 and 239.4 μg g−1, respectively) contents on one hand, and between the lower numbers of isoenzymes in the CTP-, and UTP-treated peanuts and
lower RNA (162.0 and 152.5 μg g−1, respectively) contents. The recurrent relationships of the effects of the NTP treatments of peanut were UTP > ATP > CTP
> GTP.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
The changes in foliar concentrations of volatile terpenes in response to water stress, fertilization and temperature were
analyzed in Pinus halepensis and Quercus ilex. The most abundant terpenes found in both species were α-pinene and Δ3-carene. β-Pinene and myrcene were also abundant in both species. P. halepensis concentrations were much greater than those of Q. ilex in agreement with the lack of storage in the latter species (15205.60 ± 1140.04 vs. 0.54 ± 0.08 μg g−1 [d.m.]). The drought treatment (reduction to 1/3 of full watering) significantly increased the total terpene concentrations
in both species (54% in P. halepensis and 119% in Q. ilex). The fertilization treatment (addition of either 250 kg N ha−1 or 250 kg P ha−1 or both) had no significant effects on terpene foliar concentrations. The terpene concentrations increased from 0.25 μg g−1 [d.m.] at 30°C to 0.70 μg g−1 [d.m.] at 40°C in Q. ilex (the non-storing species) and from 2,240 μg g−1 [d.m.] at 30°C to 15,621 μg g−1 [d.m.] at 40°C in P. halepensis (the storing species). Both species presented negative relationship between terpene concentrations and relative water contents
(RWC). The results of this study show that higher terpene concentrations can be expected in the warmer and drier conditions
predicted for the next decades in the Mediterranean region. 相似文献
19.
Dimethylsulfoniopropionate (DMSP) is an important component of the global sulfur cycle and may be involved, via its cleavage product dimethylsulfide, in climate regulation. Although it is common in many algae, reports of DMSP in animals, particularly tropical invertebrates, are limited. This study examined the distribution of DMSP in a diverse group of coral reef invertebrates. DMSP was present in all 22 species of cnidarians and ranged from 9 to 723 μmol g−1 of dry mass (DM) with a mean (± 1SD) of 110 ± 180 μmol g−1 DM. It was not detected in a flatworm and an ascidian or in two of five sponges. Concentrations in sponges ranged from undetectable to 16 μmol g−1 DM with a mean of 4 ± 7 μmol g−1 DM. Within the cnidarians, DMSP concentrations did not differ among orders. Among cnidarian species, DMSP concentrations were correlated with symbiotic zooxanthellae densities. Within cnidarian species, DMSP concentrations of individuals were positively correlated with zooxanthellae densities in three of the four species examined. We speculate that DMSP is dietarily derived in sponges and derived from zooxanthellae in the cnidarians. The functions of DMSP in coral reef invertebrates are not known. 相似文献
20.
Chlorophyll-a (chl-a) and carotenoid pigments of the zooxanthellate octocoral Sinularia flexibilis were analyzed using high performance liquid chromatography following exposure to three light intensities for over 30 days.
From the coral fragments located at different light intensities, a total carotenoid of >41 μg g−1 dry weight, including peridinin, xanthophylls (likely diadinoxanthin + diatoxanthin), and chl-a as the most abundant pigments, with minor contents of astaxantin and β-carotene were detected. The whole content of chl-a weighed 5 μg g−1 dry weight in all coral colonies. Chl-a and carotenoids contributed 11.2% and 88.2%, respectively, to all pigments detected, and together accounted for 99.4% of
the total pigments present. The highest contents of carotenoids and chl-a was observed in the coral grafts placed in an irradiance of 100 μmol quanta m−2 s−1; they showed lower ratios of total carotenoids: chl-a compared to those exposed to 400 μmol quanta m−2 s−1 after >30 days of incubation. The ratios of peridinin and xanthophylls with respect to chl-a from the colonies at 400 μmol quanta m−2 s−1 were approximately double those observed at irradiances of 100 and 200 μmol quanta m−2 s−1. Partial quantification of pigments in this study showed that the carotenoids of S. flexibilis showed a decrease at irradiances above 100 μmol quanta m−2 s−1, with the exception of an increase in β-carotene at 200 μmol quanta m−2 s−1. 相似文献