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1.
C. T. Perry 《Coral reefs (Online)》1998,17(3):277-287
Macroboring organisms are recognised as key agents of reef framework modification and destruction, and while recent studies
in the Pacific have improved understanding of spatial variations in macroboring community structure, and rates of macroboring
within individual reefs, comparable studies from the Caribbean are largely lacking. This study assesses the distribution of
macroboring species and the degree of framework infestation across the reefs at Discovery Bay, north Jamaica. Although individual
species of borers exhibit variable distributions across the reef, relative abundances of the main groups of macroborers (sponges,
bivalves, worms) illustrate clear distributional trends. Sponges are dominant at fore-reef sites, while sipunculan and polychaete
worms are only of importance at back-reef/lagoon and shallow fore-reef sites. Bivalves are locally important within back-reef
and lagoon patch reef framework. Average percentages of internal bioerosion (macroboring) vary between sites, but are highest
at back-reef and deep fore-reef sites. No systematic pattern of variation occurs within back-reef/lagoon samples, but a significant
trend of increased macroboring is recognised with increased water depth on the fore-reef. In addition, significant differences
in terms of the susceptibility of individual coral species are recognised. These factors are likely to result in biasing of
the fossil record, with variable styles of preservation evident both between sites (i.e. with depth/environment) and within
sites (i.e. between coral species).
Accepted: 1 June 1998 相似文献
2.
Evidence for active microbial nitrogen transformations in sea ice (Gulf of Bothnia, Baltic Sea) in midwinter 总被引:5,自引:3,他引:2
Hermanni Kaartokallio 《Polar Biology》2001,24(1):21-28
Nutrient concentrations, chlorophyll-a, bacterial biomass and relative activity of denitrifying organisms were investigated from ice-core, brine and underlying
water samples in February 1998 in the Gulf of Bothnia, Baltic Sea. Examined sea ice was typical for the Baltic Sea; ice bulk
salinity varied from 0.1 to 1.6 psu, and in underlying water salinity was from 4.2 to 4.7 psu. In 2- to 3-months-old sea ice
(thickness 0.4–0.6 m), sea-ice communities were at the winter stage; chl-a concentrations were generally below 1 mg m−3 and heterotrophic organisms composed 7–20% of organism assemblage. In 1-month-old ice (thickness 0.2–0.25 m), an ice spring
bloom was already developing and chl-a concentrations were up to 5.6 mg m−3. In relation to low salinity, high concentrations of NH+
4, NO−
2, PO3+
4 and SiOH4 were found in the ice column. The results suggest that the upper part of ice accumulates atmospheric nutrient load during
the ice season, and nutrients in the upper 10–20 cm of ice are mainly of atmospheric origin. The most important biological
processes controlling the sea-ice nutrient status are nutrient regeneration, nutrient uptake and nitrogen transformations.
Nutrient regeneration is specially active in the middle parts of the 50- to 60-cm-thick ice and subsequent accumulation of
nutrients probably enhances the ice spring bloom. Nitrite accumulation and denitrifying activity were located in the same
ice layers with nutrient regeneration, which together with the observed significant correlation between the concentrations
of nitrogenous nutrients points to active nitrogen transformations occurring in the interior layers of sea ice in the Baltic
Sea.
Accepted: 12 June 2000 相似文献
3.
K. E. Fabricius 《Coral reefs (Online)》1997,16(3):159-167
The distribution and abundance of soft coral genera on reefs of the central Great Barrier Reef was investigated in relation
to reef position, recent history of disturbance, wave exposure, substratum slope and depth. Eighty-five 25 m long transects
were surveyed at 10 m depth on windward sides of 14 mid- and outer-shelf reefs. A further 75 transects in different zones
on one mid-shelf reef (Davies Reef) between 5 and 30 m depth were investigated. The crown-of-thorns starfish Acanthaster planci had caused large-scale mortality of scleractinians on eight of these reefs five to ten years prior to the study, and as a
result, scleractinian cover was only 35–55% of that on the six unimpacted reefs. On the impacted reefs, stony corals with
massive and encrusting growths form had smaller average colony diameters but similar or slightly lower numerical abundance.
In contrast, mean colony size, cover and abundance of branching stony corals showed no difference between impacted and unimpacted
reefs. Twenty-four genera of soft corals (in eight families) were recorded, and none showed different abundance or cover in
areas of former A. planci impact, compared to unaffected sites. Similarly, no difference was detected among locations in the numbers or area cover
of sponges, tunicates, zoanthids, Halimeda or other macro-algae. Mean soft coral cover was 2 to 5% at 10 m on sheltered mid-shelf reefs, and 12 to 17% on more current-exposed
reefs. Highest cover and abundances generally occurred on platforms of outer-shelf reefs exposed to relatively strong currents
but low wave energy. On Davies Reef, cover and colony numbers of the families Nephtheidae and Xeniidae were low within the
zone of wave impact, in flow-protected bays and lagoons, on shaded steep slopes, and at depths above 10 and below 25 m. In
contrast, distributions of genera of the family Alcyoniidae were not related to these physical parameters. The physical conditions
of a large proportion of habitats appear “sub-optimal” for the fastest growing taxa, possibly preventing an invasion of the
cleared space. Thus, in the absence of additional stress these shallow-water fore-reef zones appear sufficiently resilient
to return to their pre-outbreak state of scleractinian dominance.
Accepted: 20 August 1996 相似文献
4.
The biofiltration of dimethyl sulphide (Me2S) and other volatile sulphur compounds results in the accumulation of the metabolite sulphuric acid in the carrier material.
Regeneration of an acidified (pH 4.7), Hyphomicrobium-MS3-inoculated compost biofilter degrading Me2S was not possible by trickling tap water (days 0–28) or a KH2PO4/K2HPO4 buffer solution (1.26 g PO3-
4 l-1, pH 7) (days 29–47) over the bioreactor at a superficial liquid flow rate of 34 lm-2 day-1. Since the protons produced displaced nutrient cations (Na+, K+, Ca2+, Mg2+, NH+
4) from the cation-exchange sites on the compost material, 95% of the SO2-
4 was leached as the corresponding sulphate salts and not as sulphuric acid. Concomitantly, the pH of the compost material
decreased from 4.7 to 3.9 over the 47 days rinsing period. Moreover, the rinsing procedure resulted in the leaching of essential
microbial nutrients from the compost material, such as NH+
4 (22.3% wash-out over the 47-day rinsing period) and PO3-
4 (39.3% washout over the 28-day tap-water rinsing period). However, mixing limestone powder into the Me2S-degrading compost biofilter was a successful approach to controlling the pH in the optimal range for the inoculum Hyphomicrobium MS3 (pH 6–7). A stoichiometric neutralisation reaction (molar ratio CaCO3/H2SO4=1.1) was observed between the CaCO3 added and the metabolite of the Me2S degradation, while high elimination capacities (above 100 g Me2S m-3 day-1) were obtained over a prolonged (more than 100 days) period.
Received: 1 December 1995/Received revision: 26 April 1995 Accepted: 29 April 1996 相似文献
5.
A spectacular mound-like reef formation (126 m in circumference, 10 m high) dominated by highly arched and record-size colonies
of the unattached mushroom coral Halomitra pileus, along with 17 other species of the family Fungiidae, occurs in 31 m of water on the sedimentary lagoon floor of the Great
Astrolabe Reef, Fiji. Core samples show radiocarbon dates which indicate that the formation hypothetically began building
∼4500 y ago, with a calculated mean accretion rate of 2.2 mm ⋅ y-1. The majority of fossil and living material is contributed by H. pileus colonies between 40–70 cm mean diameter, with some individuals up to 1.5 m in diameter. The size, fungiid diversity, and
geological history of the bioherm is unprecedented and represents the first example of a coral reef constructed almost entirely
by Fungiidae.
Accepted: 29 July 1996 相似文献
6.
Peter S. Vroom Kimberly N. Page Kimberly A. Peyton J. Kanekoa Kukea-Shultz 《Coral reefs (Online)》2005,24(4):574-581
Reefs in tropical atoll systems have historically been described on a geomorphic basis, and segregated into loosely defined
fore-reef, back-reef, and lagoonal reef zones. However, recent oceanographic monitoring data have shown that physical factors
within a single geomorphic zone can vary significantly, calling into question whether benthic communities within a single
zone are biologically similar. To determine the amount of benthic variability that may occur in a geomorphic zone, percent
cover of benthic organisms was determined at the species level for 28 sites in three geomorphic zones at French Frigate Shoals,
Northwestern Hawai‘ian Islands. Multivariate statistical analyses found most windward fore-reef and back-reef sites to be
statistically similar, but considerable variation to exist among sites within calmer lagoonal areas. Surveys revealed macroalgae
to dominate over scleractinian coral species at the majority of sites in this healthy, subtropical reef system, although select
lagoonal areas were dominated by dense coral communities. 相似文献
7.
Kikai-jima in the central Ryukyu Islands of Japan is fringed by exposed terraces of Holocene reefs, which formed as a result
of periodic local tectonic uplift associated with subduction/collision. The terraces form four topographically distinct features
(TI-IV) around the island and represent reefs that grew to sea level at 9000–6065 y BP, 6065–3390 y BP, 3790–2630 y BP, and
2870 to 1550 y BP. The modern reef terrace has been growing since approximately 1550 y BP. The reef terraces were uplifted
sequentially around 6050 y BP (4 m), 3390–3790 y BP (2.5 m), 2630–2870 y BP (1 m) and 1550 y BP (2.5 m). Five sites were studied
to define reef development in response to periodic relative sea level fall and different stillstand recovery periods. Thirty
coral genera and 70 species were recorded from four distinct shallow reef flat to upper reef slope and one deeper reef slope
coral assemblage. Significant lateral variations in total coral abundance, genera number, diversity, and the coverage density
of Acropora spp. and Faviids occur both within and between the terraces. Stratigraphically, drill core and outcrop data recorded shallowing
upward sequences characterised by tabulate Acropora spp. overlying massive Porites sp. and Faviids. The biological variations may represent growth strategies responding to initial colonisation, episodic perturbation
(relative sea level fall) and differing recovery times during stillstands, and indicate a reef ecosystem stable and strong
enough to recover after substantial perturbations. However, this study suggests that relatively small geological changes have
had substantial biological effects, and modelling indicates that such changes would have been more profound had a third factor,
such as substrate angle, varied more dramatically. In such a case, the drowning growth strategy exhibited in the drill core
transect may have been more prevalent, and reefs would be struggling to grow around Kikai-jima today.
Accepted: 27 May 1998 相似文献
8.
Growth forms and palaeoenvironmental interpretation of stromatoporoids in a Middle Devonian reef, southern Morocco (west Sahara) 总被引:1,自引:0,他引:1
Growth forms of well-preserved stromatoporoids, including genera Actinostroma, Stachyodes, and Stromatopora, are described for the first time from the Devonian Sabkhat Lafayrina reef complex of southern Morocco (west Sahara), one of the best exposed Middle-Devonian stromatoporoid-dominated fossil reefs. Three facies types representing the well illuminated fore-reef, reef-core and transition to back-reef facies display the distribution and growth of stromatoporoids in a high latitude setting at 40–50° south of the palaeoequator. Stromatoporoids are largely in growth position and reflect the well-preserved reef architecture. Although outcrops are low topography, the reef's prominent profile is indicated by presence of spur and groove form and a clearly defined reef margin. Stromatoporoids are mostly laminar and domical forms, with little evidence of ragged margins, and indicate normal turbulence shallow waters, with low sediment deposition. 相似文献
9.
New estimates of global and regional coral reef areas 总被引:5,自引:0,他引:5
Global and regional coral reef area statistics are of considerable value in fields ranging from global environmental change
to fisheries to conservation. Although widely quoted, Smith’s 1978 figure of 600 000 km2 is only an approximate calculation. The World Conservation Monitoring Centre has prepared a new estimate of reef coverage
by mapping emergent reef crest and very shallow reef systems. These data were rasterised, using 1 km grid squares, as a means
of reducing errors arising from variation in scale. Global and regional reef coverages were calculated from the resultant
grid. The total global area is estimated at 255 000 km2, considerably lower than many previous estimates. Variation in reef area estimates is, in part, a function of variation in
reef definition.
Accepted: 3 April 1997 相似文献
10.
A. Lugo-Fernández H. H. Roberts W. J. Wiseman Jr. B. L. Carter 《Coral reefs (Online)》1998,17(4):343-349
A two-week study, at Tague Reef, St. Croix, USVI investigated the magnitude and spatial variation of tides, sea level differences,
infragravity waves, and unidirectional cross-reef currents on a modern coral reef. Infragravity oscillations of water level
(∼ 27 min period) of 1–2 cm height correlate with a quarter wavelength resonance over the shelf. Particle displacements associated
with these waves may be important to the dispersive characteristics of the reef environment. Estimates of cross-reef mass
transport per unit width ranged from 0.058 to 0.032 m2s -1. Sea level differences across the reef (1–4 cm) varied at diurnal and infragravity periods with contributions from wave set-up,
and a small contribution from cross-shelf wind stress to the observed sea level differences. The quadratic bottom friction
coefficient over the reef was estimated at 0.06–0.2, 20–70 times greater than on open shelves, reflecting the reef’s extreme
bottom roughness.
Accepted: 28 February 1998 相似文献
11.
Sponge populations were surveyed at different depths in three zones of Davies Reef, a large platform reef of the central Great Barrier Reef. Depth is the major discriminatory factor as few sponges are found within the first 10 m depth and maximal populations occur between 15 m and 30 m on fore-reef, lagoon and back-reef slopes. Reef location is another major factor, with the lagoon containing a significantly different sponge population to either the fore-reef or the back-reef slopes. Physical factors are considered to be the major influences behind these patterns. Physical turbulence is strongest within the first 10 m and apparently limits sponge growth within these shallow zones. Insufficient photosynthetic radiation limits the growth of the sponge population below 30 m depth as many of the species are phototrophic with a dependence on cyanobacterial symbionts for nutrition. Sponge populations on the outer (fore- and back-) reef slopes are comparable with each other but different from those on lagoon slopes where currents are reduced and fine sediment loads are higher. The largest populations occur on the back-reef slope where currents are stronger and there are possibly higher concentrations of organic nutrients originating from the more productive shallow parts of the reef. While there are correlations between sponge populations and environmental parameters, data are insufficient to enable more definitive conclusions to be drawn. Most sponge species are distributed widely over the reef, however, some are restricted to a few habitats and, hence, may be used to characterize those habitats. 相似文献
12.
A. König C. Zaborosch A. Muscat K.-D. Vorlop F. Spener 《Applied microbiology and biotechnology》1996,45(6):844-850
Amperometric biosensors for naphthalene were developed using either immobilized Sphingomonas sp. B1 or Pseudomonas fluorescens WW4 cells. The microorganisms were immobilized within a polyurethane-based hydrogel, which was used for a microbial biosensor
for the first time. Both strains were shown to be equally suited for the quantification of naphthalene in aqueous solutions.
The biosensors were tested in a flow-through system and a stirred cell (batch method). In both systems a linear response down
to the detection limit was obtained. Measurements in the flow-through system gave sensitivities of up to 1.2 nA mg−1 l−1 and a linear range from 0.03 mg/l to 2.0 mg/l. The response time (t
95) was 2 min and the sample throughput six per hour; the repeatability was within ±5 %. With the batch method, sensitivities
of between 3 nA mg−1 l−1 and 5 nA mg−1l−1 and a linear range of 0.01–3.0 mg/l were obtained; the response time was between 3 min and 5 min. The sensors reached an
operational lifetime of up to 20 days. The sensitivity of both sensors for naphthalene was, in most cases, more than four
times higher than for various other substrates.
Received: 18 October 1995/Received revision: 22 December 1995/Accepted: 22 January 1996 相似文献
13.
《Aquatic Botany》1986,24(2):115-130
A new method for interpreting branching morphology is introduced and demonstrated to be a practical means of assessing ecological events. The “turf” configuration of Laurencia papillosa (Forssk.) Grev. and the vegetative fragmentation of Acanthophora spicifera (Vahl) Børg. are examined on a fringing reef platform at Galeta Point, Panama. Predictions of branching morphology are tested by comparing plants in the fore-reef, that are exposed to intense wave action and potentially large numbers of herbivorous fish, with those in the back-reef, where wave action and grazing are minimal. Differences in plant size, number of branches and length of branch segments, together with the number and location of missing branches, are quantified. It is shown that in some instances branching morphology can be used to test ecological events.There is little difference in the branching structure of Laurencia papillosa in the foreand back-reef. The number and the length of branch segments were similar and few branches were lost to wave action or herbivory. Some grazing of determinate branches occurred on the reef flat, but this had no apparent effect upon branching morphology. Plants in the fore-reef, however, were significantly smaller than those in the back-reef. It follows that fore-reef plants are best characterized as dwarf plants as opposed to a “turf”.The branching morphology of Acanthophora spicifera is altered by wave action in the fore-reef. Plants were shorter and had proportionally fewer branches in the fore-reef than in the back-reef. There was, however, no difference in the length of branch segments between the two areas. Numerous branching scars, resulting from the loss of indeterminate branches, were found. In the fore-reef, the smaller-sized plants of A. spicifera are best explained by vegetative fragmentation. 相似文献
14.
Benoy K. Ghose 《Palaeogeography, Palaeoclimatology, Palaeoecology》1977,22(3):231-256
The paleoecology of reefal foraminifers and algae assumes a considerable importance in determining and delineating sub-environments of ancient reefs, especially those of non-coral origin.A review of the ecologic distribution of the Cenozoic larger foraminifers in different biofacies of the reef-complex environment has revealed the following: (1) a prolific growth of “Alveolina” was possible in the back-reef region near the reef core; (2) Orbitolites and Marginopora preferred sheltered waters on the reef-flat and in the back-reef zones; (3) nummulitids and Discocyclina thrived in both fore- and back-reef shoal areas, but the species living in the former are much stouter than those living in the latter; (4) Heterostegina is and, in the geologic past, was a form, preferring quieter waters of the back-reef lagoons and reef-flat pools; (5) Pellatispira was a typical fore-reef form.Smaller foraminifers, as a whole, are dominant in back-reef lagoons. An abundance of miliolids indicates a sheltered environment prevailing in the reef-flat pools and back-reef zones, whereas reef flats, in general, are characterized by a paucity of smaller foraminifers. An increase in the number of nodosariids and globigerinids points to a fore-reef environment, the depth of which is indicated by the relative abundance of the latter group. Encrusting foraminifers are characteristic of the reef core and are important constituents of for-algal (foraminiferal + algal) reef complexes.Of the algae, the calcarous chlorophyte Halimeda is relatively more abundant in the sheltered parts of a reef-complex, especially the lagoons, where water is moderately agitated and clear; its sudden abundance in the geologic record indicates the advent of a reefal environment. An abundance of the calcareous chlorophyte Dasycladaceae indicates the shallow back-reef areas adjacent to the reef core. Articulated coralline algae are associated with reef-complexes but are varied in their adaptability and, hence, are widely distributed in different parts of the complex. Abundant crustose coralline algae almost certainly indicate a reef-core sub-environment; their skeletons are among the chief constructional units of the core. They increase in abundance towards the outer edge of the reef core and decrease away from it. 相似文献
15.
K. Katoh M. Ohbo M. Wakui 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1996,166(6):369-374
In order to investigate the cellular mechanisms involved in amylase release in response to stimulation with short-chain fatty
acids, changes in intracellular calcium concentration ([Ca2+]i), membrane current and amylase release were measured in pancreatic acinar cells of sheep. Both octanoate and acetylcholine
raised [Ca2+]i in acinar cells in a concentration-dependent manner. The rise in [Ca2+]i in response to the stimulation with octanoate (10 mmol ⋅ l-1) was reduced in a medium without CaCl2, but was markedly enhanced by reintroduction of CaCl2 into the medium up to 2.56 mmol ⋅ l-1. Perfusion of the cells with a medium containing octanoate (5 mmol ⋅ l-1) or acetylcholine (0.5 μmol ⋅ l-1) immediately raised inward current across the cell membrane at a holding-membrane potential of −30 mV. The inward current
became greater as the holding potential became more negative. The equilibrium potential was 1.8 mV and 3.9 mV for octanoate
and acetylcholine, respectively, being consistent with that for Cl-. Although intracellular application of octanoate through a patch-clamp pipette also raised inward current after several minutes
in some cells (4 out of 12), this possibility was significantly smaller than that for extracellular application. In other
cells, even though the intracellular application of octanoate did not cause an increase in current, it always caused responses
immediately after introduction of the fatty acid into the medium. Stimulation with fatty acid as well as acetylcholine raised
amylase release in a concentration-dependent manner in cells dispersed from tissue segments with crude collagenase and trypsin
inhibitor. Without trypsin inhibitor, crude collagenase significantly and selectively reduced the octanoate (10 mmol ⋅ l-1)-induced amylase release. Dispersion with crude collagenase and trypsin significantly reduced both responses induced by octanoate
and acetylcholine (5.5 μmol ⋅ l-1). We conclude that fatty acids and acetylcholine increase [Ca2+]i, which consequently evokes a rise in transmembrane ion (Cl-) conductance and amylase release, and that trypsin-sensitive protein(s) in the cell membrane are involved in secretory processes
activated by stimulation with fatty acids in ovine pancreatic acinar cells.
Accepted: 14 May 1996 相似文献
16.
J. N. Harney E. E. Grossman B. M. Richmond C. H. Fletcher III 《Coral reefs (Online)》2000,19(2):141-154
The origin, age, and dynamics of carbonate sediments in Kailua Bay on Oahu, Hawaii, are described. The shoreface (from shoreline
to 4 km offshore) consists of a broad (5 km2) fringing coral reef ecosystem bisected by a sinuous, shore-normal, sand-filled paleostream channel 200–300 m wide. The median
grain diameter of surface sands is finest on the beach face (<0.3 mm) and increases offshore along the channel axis. Kailua
sands are >90% biogenic carbonate, dominated by skeletal fragments of coralline algae (e.g. Porolithon, up to 50%) followed by the calcareous green alga Halimeda (up to 32%), coral fragments (1–24%), mollusc fragments (6–21%), and benthic foraminifera (1–10%). Sand composition and age
across the shoreface are correlated to carbonate production. Corals and coralline algae, principal builders of the reef framework,
are younger and more abundant in sands along the channel axis and in offshore reefal areas, while Halimeda, molluscs, and foraminifera are younger and more dominant in nearshore waters shoreward of the main region of framework building.
Shoreface sediments are relatively old. Of 20 calibrated radiocarbon dates on skeletal constituents of sand, only three are
younger than 500 years b.p.; six are 500–1000 years b.p.; six are 1000–2000 years b.p.; and five are 2000–5000 years b.p. Dated fine sands are older than medium to coarse sands and hence may constitute a reservoir of fossil carbonate that is
distributed over the entire shoreface. Dominance of fossiliferous sand indicates long storage times for carbonate grains,
which tend to decrease in size with age, such that the entire period of relative sea-level inundation (∼5000 years) is represented
in the sediment. Despite an apparently healthy modern coral ecosystem, the surficial sand pool of Kailua Bay is dominated
by sand reflecting an antecedent system, possibly one that existed under a +1–2 m sea-level high stand during the mid- to
late Holocene.
Accepted: 20 December 1999 相似文献
17.
Simultaneous nutrients and carbon removal during pretreated swine slurry degradation in a tubular biofilm photobioreactor 总被引:1,自引:0,他引:1
Ignacio de Godos Cristina González Eloy Becares Pedro A. García-Encina Raúl Muñoz 《Applied microbiology and biotechnology》2009,82(1):187-194
The biodegradation potential of an innovative enclosed tubular biofilm photobioreactor inoculated with a Chlorella sorokiniana strain and an acclimated activated sludge consortium was evaluated under continuous illumination and increasing pretreated
(centrifuged) swine slurry loading rates. This photobioreactor configuration provided simultaneous and efficient carbon, nitrogen,
and phosphorous treatment in a single-stage process at sustained nitrogen and phosphorous removals efficiencies ranging from
94% to 100% and 70–90%, respectively. Maximum total organic carbon (TOC), NH4
+, and PO4
3− removal rates of 80 ± 5 g C mr
−3 day−1, 89 ± 5 g N mr
−3 day−1, and 13 ± 3 g P mr
−3 day−1, respectively, were recorded at the highest swine slurry loadings (TOC of 1,247 ± 62 mg L−1, N–NH4
+ of 656 ± 37 mg L−1, P–PO4
3+ of 117 ± 19 mg L−1, and 7 days of hydraulic retention time). The unusual substrates diffusional pathways established within the phototrophic
biofilm (photosynthetic O2 and TOC/NH4
+ diffusing from opposite sides of the biofilm) allowed both the occurrence of a simultaneous denitrification/nitrification
process at the highest swine slurry loading rate and the protection of microalgae from any potential inhibitory effect mediated
by the combination of high pH and high NH3 concentrations. In addition, this biofilm-based photobioreactor supported efficient biomass retention (>92% of the biomass
generated during the pretreated swine slurry biodegradation). 相似文献
18.
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
19.
P. S. Kench 《Coral reefs (Online)》1998,17(2):155-168
Detailed measurements of water levels, and tide and wave-induced currents were undertaken to examine physical processes and
their relationship with morphology in the Cocos (Keeling) Islands, a medium sized atoll in the Indian Ocean. Results indicate
that the atoll structure controls both lagoon circulation and the spatial pattern of energy distribution. Lagoon circulation
is tide dominated (currents 16–31 cms-1) with flushing (2–5 days) of the lagoon occurring through the deep leeward passages. Wave- and tide-driven unidirectional
flows through shallow passages (26–65 cms-1) are important mechanisms of ocean to lagoon water exchange and contribute up to 24% of the lagoon neap tide prism. Reef
flats are dominated by wave energy (maximum velocity 140 cms-1, east) with measurements of the attenuation of wave energy between reef flats and shallow lagoon (80–90%) conforming to measurements
from fringing and barrier reefs. Spectral analysis shows that the characteristics of wave energy vary on different sectors
of the atoll, with gravity wave energy dominating the east, and infragravity wave energy dominating the southern reef flat
and passages. Wave setup at the reef crest is considered to be responsible for an identified 0.1 m higher water level in the
southern as opposed to eastern and northern atoll, which promotes higher reef flat growth. Transmission of gravity waves across
reef flats requires threshold water depths of 0.65 (east) and 0.70 m (south). The higher southern reef is an effective filter
of gravity wave energy for most tidal elevations. Differences in the type and magnitude of physical processes within the atoll
are discussed with relation to geomorphic development on Cocos.
Accepted: 28 February 1998 相似文献
20.
Bioremediation of two diesel-oil-contaminated alpine subsoils, differing in soil type and bedrock, was investigated in laboratory
experiments at 10 °C after supplementation with an inorganic fertilizer. Initial diesel oil contamination of 4000 mg kg−1 soil dry matter (dm) was reduced to 380–400 mg kg−1 dm after 155 days of incubation. In both soils, about 30 % of the diesel oil contamination (1200 mg kg−1 dm) was eliminated by abiotic processes. The residual decontamination (60 %–65 %) could be attributed to microbial degradation
activities. In both soils, the addition of a cold-adapted diesel-oil-degrading inoculum enhanced biodegradation rates only
slightly and temporarily. From C/N and N/P ratios (determined by measuring the contents of total hydrocarbons, NH4
+ N, NO3
− N and PO4
3− P) of soils␣it could be deduced that there was no nutrient deficiency during the whole incubation period. Soil biological
activities (basal respiration and dehydrogenase activity) corresponded to the course of biodegradation activities in the soils.
Received: 9 September 1996 / Accepted: 7 December 1996 相似文献