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1.
Factors influencing biodeposit production by the New Zealand freshwater mussel Echyridella menziesii
Kevin J. Collier Susan J. Clearwater Paula H. M. W. Neijenhuis Susanna A. Wood 《新西兰海洋与淡水研究杂志》2018,52(1):1-15
Laboratory experiments on the New Zealand freshwater mussel Echyridella menziesii were used to investigate the short-term effects (7–8 days) of food type on rates of biodeposition and benthic substrate respiration. Post-feeding biodeposition rates ranged from 0.34 to 1.52?mg?g?1?h?1 (mean?=?0.50?mg g?1?h?1) and were unaffected by the addition of toxin-producing Microcystis. Addition of suspended sediment (30?mg?L?1) visibly altered substrate composition, and increased total and inorganic biodeposit production rates by 24–33% compared to mussels fed commercial phytoplankton stock. Biodeposition rates of mussels in lake bed substrates were 38% higher than those in silica sand for identical feeding regimes, suggesting that a significant proportion of material produced in this experiment could have been derived from feeding on organic matter in the lake bed sediments. Respiration rates were higher in treatments with Microcystis but were unaffected by the presence of mussels. This laboratory study suggests that biodeposition by E. menziesii is resilient to short-term exposure to Microcystis, and highlights the ability of mussels to alter benthic substrate composition by incorporating suspended sediment into substrates. 相似文献
2.
Volatile fatty acid (VFA) apparent turnover rates in organic-rich marine sediments were determined by measuring whole sediment VFA concentration and the corresponding first-order reaction rate constants. In order to measure VFA concentrations, bulk wet sediment samples were basified, freeze-dried, extracted with methanol, derivatized to form methyl esters of the VFAs, and analyzed by packed-column gas chromatography using hexanoic acid as an internal standard. The detection limits for acetate, propionate, iso-butyrate and butyrate were 1.0, 0.4, 0.2 and 0.2 μmol l?1s, respectively, for 600 ml samples. Rate constants for acetate and propionate were determined by anaerobically incubating samples at in-situ temperatures with tracer levels of 14C-labelled VFAs. Metabolized label was recovered as CO2, CH4, cellular material, water-soluble material, and VFA (ether-soluble) fractions. Apparent turnover rates measured during summer and winter in anoxic Cape Lookout Bight, North Carolina (U.S.A.) sediments were in the range of 19–330 μmol l?1s h?1 for acetate and 0.7–7.0 μmol l?1s h?1 for propionate. 相似文献
3.
N. H. McCarter 《新西兰海洋与淡水研究杂志》2013,47(4):551-559
The diet of brown trout (Salmo trutta) and rainbow trout (S. gairdnerii) was studied in specimens from Lake Benmore, a deep, oligo‐trophic lake in South Island, New Zealand. Between November and July, both species fed mainly on small molluscs (Potamopyrgus antipodarum, Physa sp., and Gyraulus corinna) gleaned from the littoral weed beds. Energy values for the three species of mollusc were determined: P. antipodarum, 6000 J g‐1; G. corinna, 5500 J g‐1; Physa sp., 9800 J g‐1. Potamopyrgus antipodarum yielded little energy to the fish, unless its shell broke during passage through the gut. Physa sp. was the most profitable mollusc, irrespective of shell breakage and Potamopyrgus antipodanim the least profitable. The mean energy value per snail for G. corinna and Physa sp. eaten by rainbow trout was 25–30% less than for snails eaten by brown trout, possibly because rainbow trout ingested empty shells from the sediment surface. Rainbow trout extracted about 20% more energy than brown trout from unbroken shells. In July, 84% of the brown trout switched to predation of common bullies, Gobio‐morphus cotidianus, probably as a result of bully reproductive behaviour. Rainbow trout did not show the same change, apparently because they were feeding in deeper water where few bullies were available. The low‐energy diet and its possible connection with growth rate are discussed. 相似文献
4.
Suspended sediment (SS) is an important pollutant in freshwater ecosystems and can be detrimental to fish communities. Although macrophytes mediate sediment deposition, little effort has been put into determining how their removal affects sediment resuspension. The present study examined the immediate and long-term impacts of mechanical macrophyte removal on SS concentrations in streams. The results of this study suggest that bed disturbance during mechanical excavation of macrophytes significantly increases SS in the short term, and concentrations were found to increase by as much as 15,687 mg L–1 immediately after macrophyte removal. Significant long-term (77 day) increases in SS were also observed, indicating that without macrophytes, disturbed material is continually resuspended after excavation by fluvial processes. These results demonstrate that macrophyte removal can result in SS levels that have previously been shown to harm fish, and indicate that this activity may be more detrimental to fish than previously thought. 相似文献
5.
《Oceanologica Acta》1998,21(6):983-992
To improve the knowledge of the survival of enteric viruses in a marine environment, the influence of physico-chemical parameters (temperature, UV, salinity) on the survival of infectious poliovirus 1 and hepatitis A virus (HAV) in seawater was first studied, the influence of suspended solids (SS) on poliovirus adsorption and survival in seawater was then evaluated and the detection of rotavirus genome in environmental samples (shellfish, river water, treated wastewater) was finally investigated. The results show that temperature has a major impact on virus survival in seawater as the time necessary to inactivate 90 % of the virus (T90) is 671 days at 4 °C and only 25 days at 25 °C. Ultraviolet light (42 mW s cm−2) rapidly inactivates viruses but HAV is more resistant (T90 = 2.6 min) than the poliovirus 1 (T90 = 1.3 min). By contrast, seawater salinity has no effect on virus survival. In presence of SS, 90 % to 99.9 % of the viruses were adsorbed. This adsorption does not provide any protection for viruses with low SS concentrations (3 and 15 mg L−1) but a slight increase in virus survival was observed with a high SS concentration (500 mg L−1). Finally environmental sample analysis indicated that 20 % shellfish, about 40 % river water and 40 % treated wastewater tested positive for the rotavirus genome. 相似文献
6.
Laboratory experiments demonstrated that migrant juvenile banded kokopu (Galaxias fasciatus Gray) were more sensitive to suspended sediment (SS) than other native fish species. If juvenile migrants avoid waters made turbid by SS and their recruitment to adult habitats up stream is reduced, then adult abundance may decline in turbid rivers. To test this, we compared the abundance of diadromous native fish between turbid and clear rivers. The duration (% time) for which SS concentrations exceeded 120 mg litre‐1 (a critical level from laboratory experiments) during the migration season (August‐December) was estimated for over 150 New Zealand river sites. Turbid rivers were defined as those where SS concentrations exceeded 120 mg litre‐1 for over 20% of the time and clear rivers as those where SS concentrations exceeded 120 mg litre‐1 for less than 10% of the time. Eight turbid rivers and seven clear ones were identified where sufficient data on SS and native fish populations existed to permit a comparison. The mean occurrence of banded kokopu was reduced by 89.5% in turbid rivers and, although other diadromous fish species were also less common, banded kokopu was most affected. Densities of adult banded kokopu were also significantly lower in optimal stream habitats in three turbid compared with three matched clear rivers. We therefore concluded that the abundance of adult banded kokopu was reduced in turbid rivers and propose that this is because of reduced recruitment of juveniles in turbid rivers. 相似文献
7.
Abstract Common native fish species that are rare in New Zealand rivers with high suspended solids (SS) concentrations were identified to determine which species were likely to be most affected by high SS concentrations. Mortality rates for the three most sensitive species (banded kokopu Galaxias fasciatus, redfin bully Gobiomorphus huttoni, common smelt Retropinna retropinnd) were measured over a range of SS concentrations to identify lethal concentrations. The survival of banded kokopu and redfin bully was not reduced by SS concentrations up to 43 000 g m?3; however, the 24‐h survival of common smelt was reduced by SS concentrations over 1000 g m?3, and its median lethal concentration (LC50) was close to 3000 g m?3. SS concentrations over 3000 g m?3 for more than 24 h will therefore reduce smelt but not affect the mortality of most other common native fish species. Although mortality from high concentrations of SS can account for the scarcity of smelt in rivers with high SS concentrations, mortality from high SS does not explain the scarcity of banded kokopu or redfin bully in such rivers. High turbidity (>20 nephelometric turbidity units) is known to limit the upstream migration and recruitment of juvenile banded kokopu in rivers with increased SS concentrations. Banded kokopu is therefore affected by increased turbidity from SS rather than lethal SS concentrations. As redfin bully were not affected by either high turbidity levels or high SS concentrations, the low abundance of this species in rivers with high SS concentrations is likely to be related to the siltation of benthic habitats. 相似文献
8.
《African Journal of Marine Science》2013,35(1):169-179
Age and growth of West Coast steenbras Lithognathus aureti, sampled from two separate populations (northern and southern) along Namibia's coast, was determined using sectioned otoliths, and the results were validated using mark-recapture data. For both populations, the special three-parameter Von Bertalanffy growth model described growth adequately. Growth of the southern population was described by the equation Lt = 73.556(1?e?0.065(t+3.92)) cm and for the northern population by Lt = 84.601(1?e?0.088(t+2.756) cm. Environmental conditions, such as difference in sea surface temperature, density-dependent competition for food, or biochemical genetic variations between the two populations, are possible reasons for the geographic differences found in the growth rates and length-at-age. Slow growth and longevity are characteristics of West Coast steenbras that make it extremely susceptible to overfishing; careful management of the resource is therefore essential. 相似文献
9.
Metal concentrations (Cd, Cr, Cu, Fe, Mn and Zn) were determined in seawaters and soft tissues of Chthamalus montagui from the northwest coast of Portugal during the four seasons of 2011. The main objectives of this work were to assess seasonal and spatial variations of metals in order to detect hot spots of contamination, to establish correlations between metals in coastal seawaters and C. montagui and to calculate metal bioaccumulation factors (BAFs) in each season. Metal concentrations in coastal seawaters ranged within Cd: 1.2–35 ng L?1; Cr: 15–87 ng L?1; Mn: 77–1763 ng L?1; Cu: 126–1819 ng L?1; Fe: 430–4048 ng L?1 and Zn: 2889–16867 ng L?1 and in C. montagui ranged for Cd: 0.39–1.98 mg kg?1; Cr: 0.45–3.13 mg kg?1; Cu: 0.93–5.70 mg kg?1; Mn: 2.2–20.4 mg kg?1; Fe: 135–707 mg kg?1 and Zn: 119–782 mg kg?1. Significant spatial and seasonal variations were found between: (i) metal concentrations in seawaters and C. montagui tissues; (ii) the distribution of metal concentrations in C. montagui tissues were Fe > Zn > Mn > Cu > Cr > Cd and (iii) C. montagui showed higher bioaccumulation factors for Fe and Cd than for Cu, Mn and Zn in all seasons. Regarding the metal concentrations accumulated in C. montagui tissues during each season of 2011, the ecological quality classifications of the NW coast of Portugal varied from “Class I–Unpolluted” to “Class III–Remarkably Polluted”. 相似文献
10.
近年来,国内外广泛利用~(210)Pb法测定河口、湖泊和陆架浅海的沉积速率,为研究沉积作用提供了重要的依据。本文对中国南海4个站位进行了~(210)Pb的测定,计算了沉积速率,并对该海区的沉积特征进行了初步探讨。 相似文献
11.
Robert J. Wilcock Richard W. McDowell John M. Quinn J. Christopher Rutherford Roger G. Young Craig V. Depree 《新西兰海洋与淡水研究杂志》2020,54(4):658-678
ABSTRACT Phosphorus (P) stores in gravel-bed rivers are released for uptake by periphyton when pH levels exceed 8.5. The Tukituki River has low alkalinity water and frequently experiences periphyton blooms, and daytime pH?>?9 during summer low-flows. We measured dissolved reactive P (DRP) and EPC0, the water concentration of DRP at which no net release or sorption from the river bed occurs, in sediment samples from the Tukituki River subject to controlled pH levels before (2014) and after (2017) changes to two wastewater discharges that reduced P release to the river by 95%. DRP released from 2014 sediments at pH 8.5–10 were 30?±?10?mg/m3 above background (pH 8) whereas those released from 2017 sediments were 5?±?3?mg/m3 above background. EPC0 levels in 2014 and 2017 were 11?±?6 and 7?±?2?mg/m3, respectively. Field estimates of released DRP calculated from continuous pH and the Redfield equation suggested that most of the readily available DRP released from sediments at elevated pH is derived from material attached to recently deposited sediment. Subsequently, a reduction in wastewater inputs or agricultural runoff should reduce sediment DRP stores, and hence sediment fluxes, within a few years and mitigate periphyton blooms in addition to directly lowering water column concentrations. 相似文献
12.
Effects of the toxic dinoflagellate Alexandrium tamarense on the greenshell mussel Perna canaliculus
Abstract Oxygen consumption, grazing rate, and byssus production of the greenshell mussel Perna canaliculus were measured following exposure to bloom concentrations (106 cells l?1 ) of a toxic clone of the dinoflagellate AIexandrium tamarense (GT429), using anon‐toxic clone of the same species (PLY173) as control. Following feeding for 1 h on GT429, mussels (dry weight 54–127 mg) showed significantly increased oxygen uptake at 15°C (0.08 μl O2 (mg dry tissue weight)?1 ) compared with control mussels. However, following 24 h recovery, oxygen uptake was similar to initial values in all experimental conditions. The grazing rate of P. canaliculus fed upon toxic clone GT429 was 4.58 ± 0.76 cells mg?1 h?1 compared with 1.99 ± 0.47 cells mg?1 h?1 for PLY173. On exposure to A. tamarense, mussels maintained normal opening behaviour and there was no change in the byssus production over 24 h. It was concluded that P. canaliculus showed no dramatic physiological effects following short‐term feeding on the toxic strain of A. tamarense. During 2 weeks’ exposure to twice daily bloom concentrations of GT429, there was no mussel mortality. Toxicity in the tissues was 1295 μg STX equivalent per 100 g tissue, levels at which these mussels would be unsuitable for human or animal consumption. 相似文献
13.
K. B. Padmakumar B. R. Smitha Lathika Cicily Thomas C. L. Fanimol G. SreeRenjima N. R. Menon V. N. Sanjeevan 《Ocean Science Journal》2010,45(3):151-157
This study presents in situ evidence for the blooms of Trichodesmium erythraeum observed in the shelf waters of the South Eastern Arabian Sea (SEAS) during the onset of the southwest monsoon in June 2009. Evidence showed that water surface discoloration was caused by the accumulation of T. erythraeum, and that the water column contained a colony of T. thiebautii. The surface water color in the bloom region varied from pale brown to pinkish red. Pale brown indicated healthy algae at the peak of its photosynthetic activity, while pinkish red indicated the presence of photosynthetically less active filaments. Zooplankton abundance, especially copepodites, in the bloom area substantiated the theory that Trichodesmium filaments are excellent epiphytes to which the copepodites cling. The bloom area was very fertile with copious quantities of dissolved oxygen (6.85 ml L?1), PO4-P (0.108 μmol L?1) and SiO4 (1.29 μmol L?1). Lower NO3-N (0.028 μmol L?1) values in the bloom area did not appear to affect Trichodesmium growth from molecular nitrogen fixation. However, lower NO3-N values altered the normal phytoplankton composition of this area. 相似文献
14.
R. Chester 《Marine Chemistry》1982,11(1):1-16
The atmospheric, primary down-column and sedimentary fluxes of particulate aluminium (Alp) have been calculated for a number of regions in the Atlantic Ocean.The vertical down-column flux of Alp from Atlantic surface waters exhibits a strong geographical variation, and its magnitude is influenced by supply mechanisms, which control the surface Alp concentrations, and primary production, which affects the rate of down-column transport. Overall, the down-column transport of Alp is greatest in the marginal regions of the Atlantic. In the eastern margins the highest surface water concentrations are found in the region lying between ～30°N and ～10°N, i.e. under the general path of the northeast trades. In this region there is excellent agreement between the dry (i.e. 1 cm?1 s?1 deposition velocity) atmospheric flux (～80 000 ng Alp cm?2 y?1), the primary vertical down-column flux () and the sediment flux (～90 000 ng Alp cm?2 y?1). In the regions to the north (i.e. ～40°N to ～30°N) and to the south (i.e. ～10°N to ～5°S) the primary down-column Alp flux decreases to an average of ～19 000 μg cm?2 y?1, which makes a direct maximum contribution of ～20% of the sediment Alp requirement. In the open-ocean South Atlantic the primary down-column flux of Alp is ～3300 μg cm?2 y?1, this is similar to the dry (i.e. 1 cm?1 s?1 deposition velocity) atmospheric flux, and contributes ～20% of the Alp required by the underlying deep-sea sediment. 相似文献
15.
Cytochrome P-450 isozymes in salmonids determined with antibodies to purified forms of P-450 from rainbow trout 总被引：1，自引：0，他引：1
D.E. Williams R.C. Bender M.T. Morrissey D.P. Selivonchick D.R. Buhler 《Marine environmental research》1984,14(1-4)
Purification of cytochromes P-450 from liver microsomes of β-naphthoflavone (BNF)-fed rainbow trout yielded three apparently homogeneous forms. The major form (LM4b)* appears to be a P-448 type of cytochrome. A minor form (LM4a), having properties very similar to LM4b, was also obtained. In addition, a P-450 form (LM2) was isolated, with properties quite different from LM4a or LM4b, including a high rate of aflatoxin B1 (AFB1) metabolism (Williams & Buhler, 1983c). Antibodies to all three forms were obtained from rabbits. The IgGs prepared against LM4a and LM4b both cross-reacted (forming lines of identity) equally well with both antigens on Ouchterlony plates. Rat P-448 cross-reacted (without lines of identity) with both LM4a- and LM4b-IgG. LM4b-IgG was much more effective than LM4a-IgG for inhibition of LM4a or LM4b reconstituted benzo[a]pyrene (BP) hydroxylase, suggesting that these two antibodies recognize different antigenic sites. The LM2-IgG did not cross-react with any of the other rat or trout cytochromes P-450 examined. Levels of LM2 and LM4b in microsomes from untreated, polychlorinated biphenyl (PCB), phenobarbital (PB) or BNF-treated trout were estimated with an immunological technique involving electrophoresis on SDS-PAGE, followed by transfer to nitrocellulose and staining with either LM 2 - or LM4b -IgG. The ratio of
in microsomes from PCB- or BNF-treated rainbow trout was much higher than 1, whereas the reverse was true with microsomes from untreated rainbow trout. These results are consistent with previous observations (Vodicnik et al., 1982) that pretreatment with BNF induced the synthesis of a P-448 type cyytochrome, presumably responsible for the great increase in the metabolism and activation of BP seen in these fish. Conversely, pretreatment with PB did not affect the levels of either LM2 or LM4b. This specific immunological technique should make it possible to assay the levels of these P-450 and P-448 isozymes in various strains of rainbow trout and other species of fish. In addition, the effect of age, sex, diet and exposure to P-450 and P-448 inducers could be examined and, perhaps, utilized to predict the relative risk of certain populations to pollutants activated by these different isozymes. 相似文献
16.
B. Ben Bohlool 《新西兰海洋与淡水研究杂志》2013,47(3):271-275
Abstract Nitrogen fixing potential was measured in summer 1975 by acetylene reduction in situ at 5 stations on the intertidal flats of the Waimea Inlet, Nelson, New Zealand, which receive nutrients from several sources. Highest values (644 μmol?m?2.d?1) were obtained on sediments near an apple cannery effluent discharge and were linear through at least two tidal cycles. The cannery waste had the highest carbon to nitrogen ratio (10.3 : 1.0) of all the effluents examined and exhibited the highest rate of acetylene reduction (14.0 μmol?‐l?1.d?1). Sizeable populations of the nitrogen fixing bacteria Klebsiella pneumoniae were isolated from the cannery effluent (2 × 104 per millilitre) and also from the mud adjacent to the discharge pipe (5 × 105 per millilitrc). The stimulatory effect of the cannery effluent on nitrogen fixation in the sediment was shown to be restricted to close to the discharge point. Sediments in areas affected by slaughterhouse and sewage effluents exhibited the second and third highest rates of acetylene reduction, (130 &; 28 μmol?m?2.d?1 respectively). In both places, the activities were not restricted to the immediate vicinity of the effluent channels. Nitrogen fixation was lowest in sediments fronting a catchment of grazed pasture. Fixation was low also in sediments affected by effluents from the hydraulic debarker of a woodchip mill. 相似文献
17.
Microbially mediated methane and sulfur cycling in pockmark sediments of the Gdansk Basin, Baltic Sea 总被引：2，自引：2，他引：0
Nikolay V. Pimenov Marina O. Ulyanova Timur A. Kanapatsky Elena F. Veslopolova Pavel A. Sigalevich Vadim V. Sivkov 《Geo-Marine Letters》2010,30(3-4):439-448
In the Russian sector of the Gdansk Basin (Baltic Sea), high organic matter influx fuels microbial processes resulting in the formation of reduced sediments with elevated methane concentrations. Investigated areas of geoacoustic anomalies (～245 km2) were found to contain three distinct geomorphologic structures (pockmarks), with a total area of ～1 km2. Methane anomalies recorded in the water above one of these pockmarks were traced as high as 10 m above the bottom. In pockmark sediments, sulfate reduction and anaerobic oxidation of methane (AOM) occurred at high rates of 33 and 50 µmol dm?3 day?1, respectively. Integrated over 0–180 cm sediment depths, AOM exceeded methanogenesis almost tenfold. High AOM rates resulted from methane influx from deeper sediment layers. The δ13C signature of methane carbon (?78.1 to ?71.1‰) indicates the biogenic origin of pockmark methane. In pockmark sediments, up to 70% of reduced sulfur compounds was possibly produced via AOM. 相似文献
18.
Biogenic silica sediment constitutes one of the critical sources of particle income in the oceans. In this paper, satellite remote sensing of primary production, sinking flux, and molar ratio of Si/C were utilized to elucidate potential biogenic silica sediment in the Paleo-Yangtze Grand Underwater Delta. Primary production retrieval showed that daily primary production in the Paleo-Yangtze Grand Delta was 3.3–10.8?Mt?d?1, with 5.8?Mt?d?1 on average. Sinking flux, retrieved with in situ observations and satellite remote sensing, was within the range of 109–657?mg?Cm?2?d?1, or about 23% of total primary production, on average. A molar ratio of Si/C of 0.11–0.45 interval was used in the area, for the Paleo-Yangtze Grand Delta was similar to coastal water and affected by many factors. Considering that phytoplankton in the Paleo-Yangtze Grand Underwater Delta is mainly diatom (80% on average), about 0.21–0.88 billion tons of biogenic silica source sediment is produced in the area annually. With the reduction of land source sediment occurring in recent years in the area, biogenic silica sediment may be one of the dominant sediment sources for maintaining the future stability of the Paleo-Yangtze Grand Underwater Delta. 相似文献
19.
A mathematical model that computes the accumulation of Kepone in the striped bass food chain of the James River estuary was developed. The purpose of the model was to help understand the relationship of Kepone levels in important fish species to sediment and water column Kepone concentrations and then to address the question of why these levels still exceed Food and Drug Administration limits eight years after discharge ceased. The model considers exposure through diet and respiration at rates based on species bioenergetics. It was successfully calibrated to the Kepone concentrations observed in the period 1976 through 1982 in striped bass, white perch, and Atlantic croaker. The model indicates that for the upper levels of the food chain, diet is the major route of contamination, accounting for 87–88% of the observed concentration in croaker and white perch and 91% of the observed concentration in striped bass. The two Kepone sources; sediment and water column, contribute approximately equally to the croaker and white perch. The water column is more significant for striped bass, being the original source for approximately 60% of the observed body burdens. It was estimated that a criterion requiring Kepone concentrations in fish to be at or below 0·3 μg g?1 would require dissolved water column and sediment Kepone concentrations to be reduced to somewhere between 3 and 9 ng l?1 and 13–39 ng g?1, respectively, depending on the species. Striped bass require the greatest reductions in dissolved water column and sediment Kepone concentrations to somewhere between 3 and 5 ng l?1 and 13 and 24 ng g?1, respectively. 相似文献
20.
Jae Seong Lee Seonggil Kim Seong-Su Kim Soonmo An Yeong-Tae Kim Ok-In Choi 《Ocean Science Journal》2009,44(3):161-171
We used an oxygen microsensor for high-resolution measurements of pore water oxygen concentration in semi-closed coastal bays of the South Sea of Korea during summer. The oxygen penetration depths ranged from 0.60 to 3.65 mm. Oxygen consumption rates were estimated to be 9.1 to 59 mmol m?2 d?1 (average: 22.8 mmol m?2 d?1). At the sediment-water interface, the oxidation rates of organic carbon were estimated to be 84–545 mg C m?2 d?1 (average: 211 mg C m?2 d?1). Approximately 38% (～211 mg C m?2 d?1) of pelagic primary production was regenerated in the surface sediment, indicating the tight benthic-pelagic coupling in the coastal sea of the South Sea of Korea. 相似文献