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1.
Fine-scale movement patterns in penaeid prawns are rarely observed in situ, but are essential in understanding habitat use,
foraging, and anti-predator behaviour. Acoustic telemetry was applied to examine the activity, space utilization, and habitat
use of the eastern king prawn Penaeus (Melicertus) plebejus, at small temporal and spatial scales. Tracking of sub-adult P. plebejus (n = 9) in Wallagoot Lake (36.789°S, 149.959°E; 23 April–12 May 2009) and calculation of a minimum activity index (MAI) revealed high variation in activity rates across diel periods and in different habitats. Elevated activity rates and movement
indicated foraging in unvegetated habitats during the night. Areas within the 95 and 50% space utilization contours averaged
2,654.1 ± 502.0 and 379.9 ± 103.9 m2, respectively, and there was a significant negative relationship between these areas and prawn activity rates in unvegetated
habitats. This study provides the first estimates of prawn activity rates and space utilization in the field. Application
of acoustic telemetry can increase knowledge of prawn movements and their interactions with other marine species in different
habitats. 相似文献
2.
Minghong Wu Wenyan Shi Haijiao Zhang Zheng Jiao Jie Chen Side Yao Guoji Ding Jiamo Fu 《Environmental Chemistry Letters》2010,8(1):25-31
A wide range of pharmaceutical compounds have been identified in the environment, and their existence is a topic of growing
concern, both for human and ecological health. The work described here has investigated the photolytic properties of L(+)-α-phenylglycine
(L-α-PG-H) in aqueous solution as it can be degraded by photo-catalysis. In 266 nm laser flash photolysis of aqueous solution
of L-α-PG-H saturated with nitrogen, two transient absorption bands are observed at 280–330 nm and 450–800 nm, respectively,
due to L-α-PG-H radical cation and hydrated electrons (eaq−). Then eaq− reacts with L-α-PG-H to form the L-α-PG-H radical anion. Decaying rate constants of eaq− observed at 720 nm is to be 8.9 × 108 dm3 mol−1 s−1. The rate constant for oxidation of L-α-PG-H by SO4
− is calculated as 4.5 × 108 and 4.3 × 108 s−1 mol−1 dm3, respectively. The dissociation constants (pKa) of L-α-PG-H is 3. Excited triplet of L-α-PG-H in solution is formed by laser
flash photolysis. The quench rate constant of L-α-PG-H excited triplet (k
s) is determined to be 1.3 × 107 dm3 mol−1 s−1 and k
0 is equal to 1.7 × 105 s−1. 相似文献
3.
The scaling of metabolic rates with body mass is one of the best known and most studied characteristics of aquatic animals.
Herein, we studied how size is related to oxygen consumption, ammonia excretion, and ingestion rates in tropical (Octopus maya) and cold-water (Enteroctopus megalocyathus) cephalopod species in an attempt to understand how size affects their metabolism. We also looked at how cephalopod metabolisms
are modulated by temperature by constructing the relationship between metabolism and temperature for some benthic octopod
species. Finally, we estimated the energy balance for O. maya and E. megalocyathus in order to validate the use of this information for aquaculture or fisheries management. In both species, oxygen consumption
and ammonia excretion increased allometrically with increasing body weight (BW) expressed as Y = aBW
b
. For oxygen consumption, b was 0.71 and 0.69 for E. megalocyathus and O. maya, respectively, and for ammonia excretion it was 0.37 and 0.43. Both species had low O/N ratios, indicating an apparent dependence
on protein energy. The mean ingestion rates for E. megalocyathus (3.1 ± 0.2% its BW day−1) and O. maya (2.9 ± 0.5% its BW day−1) indicate that voracity, which is characteristic of cephalopods, could be independent of species. The scope for growth (P = I − (H + U + R) estimated for E. megalocyathus was 28% higher than that observed in O. maya (320 vs. 249 kJ day−1 kg−1). Thus, cold-water cephalopod species could be more efficient than tropical species. The protein and respiratory metabolisms
of O. maya, E. megalocyathus, and other octopod species are directly dependent on temperature. Our results offer complementary evidence that, as Clarke
(2004) stated, the metabolic response (R and U) cannot be determined mechanistically by temperature, as previously proposed (Gillooly et al. 2002). 相似文献
4.
Cadmium accumulation in the female shore crab Carcinus maenas during the moult cycle and ovarian maturation 总被引:2,自引:0,他引:2
The influence of moulting and ovarian maturation on cadmium accumulation in the tissues of female shore crabs Carcinus maenas exposed to 1 mg Cd l−1 in the water was investigated. Cadmium accumulation in all tissues examined was markedly increased in crabs in the postmoult
stages (A and B) compared to crabs in all other moult stages. During the moult cycle, average cadmium accumulation in the
midgut gland ranged from 29 μg Cd g−1 dw at premoult stage (D2) to 589 μg Cd g−1 dw at postmoult stage (A). Average cadmium concentrations in the haemolymph ranged from 0.56 μg Cd ml−1 at intermoult stage (C4) to 4.6 μg Cd ml−1 at postmoult stage (A), while the gills accumulated from 103 μg Cd g−1 dw in intermoult stage (C3) to 352 μg Cd g−1 dw in postmoult stage (A). Cadmium concentration in gills and haemolymph was also significantly higher in crabs in late premoult
stage (D3) compared to C4-crabs, while midgut gland cadmium concentration remained elevated in C1- and C3- intermoult stages relative to C4. During ovarian maturation the cadmium accumulation in midgut gland, gills, ovaries and haemolymph decreased. Average cadmium
concentration in the midgut gland decreased from 63 μg g−1 dw in ovarian Stage I to 19 μg g−1 dw in ovarian Stage VI. The same pattern was observed for gills, haemolymph and ovaries. The present study demonstrates that
cadmium accumulation in the female shore crab strongly depends on the physiological status of the animal. A possible association
between physiological calcium requirements and cadmium accumulation during moulting is discussed.
Received: 20 January 2000 / Accepted: 20 July 2000 相似文献
5.
Andrew McMinn Andrew Pankowskii Chris Ashworth Ranjeet Bhagooli Peter Ralph Ken Ryan 《Marine Biology》2010,157(6):1345-1356
Primary production at Antarctic coastal sites is contributed from sea ice algae, phytoplankton and benthic algae. Oxygen microelectrodes
were used to estimate sea ice and benthic primary production at several sites around Casey, a coastal area in eastern Antarctica.
Maximum oxygen export from sea ice was 0.95 mmol O2 m−2 h−1 (~11.7 mg C m−2 h−1) while from the sediment it was 6.08 mmol O2 m−2 h−1 (~70.8 mg C m−2 h−1). When the ice was present O2 export from the benthos was either low or negative. Sea ice algae assimilation rates were up to 3.77 mg C (mg Chl-a)−1 h−1 while those from the benthos were up to 1.53 mg C (mg Chl-a)−1 h−1. The contribution of the major components of primary productivity was assessed using fluorometric techniques. When the ice
was present approximately 55–65% of total daily primary production occurred in the sea ice with the remainder unequally partitioned
between the sediment and the water column. When the ice was absent, the benthos contributed nearly 90% of the primary production. 相似文献
6.
Rates of respiration and protein synthesis were measured during embryonic and larval development of Antarctic asteroids with
different life-history modes (non-feeding and feeding larvae: Acodontaster hodgsoni, Porania antarctica, Odontaster meridionalis). Patterns of respiration for these species all show an increase during embryogenesis, with subsequent maintenance of routine
respiration (“starvation resistance”), even in the absence of food for ~4 months (O. meridionalis). Fractional rates of protein synthesis (i.e., rate per unit mass of whole-body protein content) in the Antarctic larvae
are essentially identical to those of temperate species. Larvae of O. meridionalis had an average fractional synthesis rate of 0.52% ± 0.05 h−1 at −1.0°C, which is comparable to the temperate asteroid Asterina miniata at 0.53% ± 0.14 h−1 at 15°C. For embryos of the asteroids A. hodgsoni and P. antarctica, fractional rates of protein synthesis (~0.2% h−1) also are comparable to those reported for embryos of temperate echinoderm species. While rates of synthesis are high, rates
of protein deposition are relatively low (percent of protein synthesized that is retained for growth). During a ~4 month growth
period for larvae of O. meridionalis, the average protein depositional efficiency was 5.2%. This contrasts with higher rates of depositional efficiency reported
for similar developmental stages of temperate echinoderm species. The biological significance of maintaining high rates of
macromolecular synthesis for species with low rates of cell division and low protein depositional efficiencies is intriguing
in the context of understanding the mechanistic bases of extended life spans and dispersal potential in response to changing
Antarctic environments. 相似文献
7.
E. Pfeiler 《Marine Biology》1997,127(4):571-578
Bonefish (Albula sp.) larvae (leptocephali) from the Gulf of California complete metamorphosis in ˜10 d in natural seawater (35‰S; Ca2+ conc = 10.5 mM). The increase in ossification that occurs near the end of the non-feeding metamorphic period, in addition to the ability
of larvae to complete metamorphosis in dilute seawater (8‰ S) prompted the present study, where the effects of varying the
external calcium ion concentration, [Ca2+]e, of artificial seawater (ASW) on the survival, development and internal (whole-body) calcium ion content, (Ca2+)i, of unfed metamorphosing larvae were investigated. Early-metamorphosing larvae placed in␣ASW, where [Ca2+]e = 10.1 mM, survived for up to 10 d and developed normally without exogenous nutrients. In shorter-term experiments (4 to 5 d), no differences
in survival were found for larvae in ASW with [Ca2+]e rang-ing from 1.5 to 10.1 mM. However, in Ca2+-free ASW, most larvae died within 27 h and no larvae survived more than 42 h; the median lethal time (LT50), and its 95% confidence limits, were 14.5 (10.0 to 20.9) h. High mortality (81% after 20 h) also occurred in 1.0 mM Ca2+ ASW, but 2 of 16 larvae tested survived for 96 h. The 96 h median tolerance limit (TLM), corrected for control mortality, was 1.2 mM Ca2+. In natural seawater, larval (Ca2+)i remained relatively constant ( = 0.419 mg larva−1)␣in early- and intermediate-metamorphosing larvae, and then increased to a mean value of 0.739 mg larva−1 in advanced larvae, indicating that Ca2+ was␣taken up from the medium at this stage; the increase in (Ca2+)i corresponded to the period of ossification of the vertebral column. Internal (whole-body) magnesium ion content (Mg2+)i showed no significant change during metamorphosis ( = 0.089 mg larva−1). No significant differences in (Ca2+)i were found in advanced larvae in natural seawater and those in ASW, with [Ca2+]e ranging from 2.0 to 10.1 mM. However, clearing and staining revealed that ossification of the vertebral column had not yet occurred in advanced larvae
from 2.0 to 10.1 mM Ca2+ ASW. Also, low [Ca2+]e (1.0 to 2.0 mM) usually produced deformed larvae that swam erratically, at times showing “whirling” behavior.
Received: 21 August 1996 / Accepted: 26 August 1996 相似文献
8.
Bacterial abundance, production, and extracellular enzyme activity were determined in the shallow water column, in the epiphytic
community of Thalassia
testudinum, and at the sediment surface along with total carbon, nitrogen, and phosphorus in Florida Bay, a subtropical seagrass estuary.
Data were statistically reduced by principle components analysis (PCA) and multidimensional scaling and related to T. testudinum leaf total phosphorus content and phytoplankton biomass. Each zone (i.e., pelagic, epiphytic, and surface sediment community)
was significantly dissimilar to each other (Global R = 0.65). Pelagic aminopeptidase and sum of carbon hydrolytic enzyme (esterase, peptidase, and α- and β-glucosidase) activities
ranged from 8 to 284 mg N m−2 day−1 and 113–1,671 mg C m−2 day−1, respectively, and were 1–3 orders of magnitude higher than epiphytic and sediment surface activities. Due to the phosphorus-limited
nature of Florida Bay, alkaline phosphatase activity was similar between pelagic (51–710 mg P m−2 day−1) and sediment (77–224 mg P m−2 day−1) zones but lower in the epiphytes (1.1–5.2 mg P m−2 day−1). Total (and/or organic) C (111–311 g C m−2), N (9.4–27.2 g N m−2), and P (212–1,623 mg P m−2) content were the highest in the sediment surface and typically the lowest in the seagrass epiphytes, ranging from 0.6 to
8.7 g C m−2, 0.02–0.99 g N m−2, and 0.5–43.5 mg P m−2. Unlike nutrient content and enzyme activities, bacterial production was highest in the epiphytes (8.0–235.1 mg C m−2 day−1) and sediment surface (11.5–233.2 mg C m−2 day−1) and low in the water column (1.6–85.6 mg C m−2 day−1). At an assumed 50% bacterial growth efficiency, for example, extracellular enzyme hydrolysis could supply 1.8 and 69% of
epiphytic and sediment bacteria carbon demand, respectively, while pelagic bacteria could fulfill their carbon demand completely
by enzyme-hydrolyzable organic matter. Similarly, previously measured T. testudinum extracellular photosynthetic carbon exudation rates could not satisfy epiphytic and sediment surface bacterial carbon demand,
suggesting that epiphytic algae and microphytobenthos might provide usable substrates to support high benthic bacterial production
rates. PCA revealed that T. testudinum nutrient content was related positively to epiphytic nutrient content and carbon hydrolase activity in the sediment, but
unrelated to pelagic variables. Phytoplankton biomass correlated positively with all pelagic components and sediment aminopeptidase
activity but negatively with epiphytic alkaline phosphatase activity. In conclusion, seagrass production and nutrient content
was unrelated to pelagic bacteria activity, but did influence extracellular enzyme hydrolysis at the sediment surface and
in the epiphytes. This study suggests that seagrass-derived organic matter is of secondary importance in Florida Bay and that
bacteria rely primarily on algal/cyanobacteria production. Pelagic bacteria seem coupled to phytoplankton, while the benthic
community appears supported by epiphytic and/or microphytobenthos production. 相似文献
9.
A series of experiments investigated the potential role of microbial mats in nutrition of the early settlement stages of Penaeus semisulcatus. From 3 days post-metamorphosis, the microbial mat supported high growth and survival rates in postlarvae, equivalent to
that supported by a control diet of Artemia nauplii and mussel. Examination of gut contents indicated that benthic postlarvae feed indiscriminately on the microbial
mat. However, when postlarvae were fed separated size-fractions of the microbial mat, only the fraction containing a high
concentration of infauna (mainly nematodes) was able to support the same growth as intact microbial mat. This appears to be
due to the low nitrogen content (0.4–0.9 mmol g−1) of the various size-fractions, compared to that of infauna (4.0 mmol g−1). The stable isotope composition of the dietary size-fractions and postlarval shrimp tissue supports the hypothesis that
the shrimp assimilated C and N primarily from the associated infauna. This may be due to selective feeding that is not apparent
from stomach contents, due to rapid digestion of fauna soft tissues, or to differential assimilation of infaunal prey relative
to other microbial mat components. The results demonstrate that microbial mats may support survival and growth in early-stage
penaeid shrimp postlarvae on intertidal mud flats. 相似文献
10.
Kate F. Lankin Myron A. Peck Lawrence J. Buckley David A. Bengtson 《Marine Biology》2008,155(5):461-472
Rates of routine respiration (R
R, μl O2 fish−1 h−1) and total ammonia nitrogen excretion (E
R, μg NH4–N + NH3–N fish−1 h−1) were measured on larval and juvenile haddock (Melanogrammus aeglefinus) to ascertain how energy losses due to metabolism were influenced by temperature (T), dry body mass (M
D, mg) and specific growth rate (SGR, % per day). R
R and E
R increased with M
D according to y = a · M
D
b
with b-values of 0.96, 0.98, 1.14, and 0.89, 0.78, 0.74, respectively, at 10, 7, and 4°C, respectively. Multiple regressions explained
98% of the variability in the combined effects of M
D and T on R
R and E
R in larval haddock: R
R = 0.97 · M
D
0.98 · e0.092 · T
; E
R = 0.06 · M
D
0.79 · e0.092 · T
. In young juvenile (24–30 mm standard length) haddock, R
R tended to decline (P = 0.06) and E
R significantly declined (P = 0.02) with increasing SGR. O:N ratios significantly increased with increasing SGR suggesting that N was spared in relatively
fast-growing individuals. Our results for young larval and juvenile haddock suggest: (1) nearly isometric scaling of R
R with increasing body size, (2) allometric scaling of E
R with increasing body size, (3) Q
10 values of 2.5 for both R
R and E
R, (4) metabolic differences in substrate utilization between relatively fast- and slow-growing individuals, and (5) that rates
of routine energy loss and growth were not positively related. The measurements in this study will provide robust parameter
estimates for individual-based models that are currently being utilized to investigate how variability in climatic forcing
influences the vital rates of early life stages of haddock. Our results also stress that inter-individual differences in rates
of energy loss should not be overlooked as a factor influencing growth variability among individuals. 相似文献
11.
The effects of blooms of the cyanobacterium Trichodesmium spp. on penaeid prawn larvae were examined using in situ and laboratory rearing experiments and plankton surveys in Albatross
Bay, Gulf of Carpentaria, Australia. The in situ experiments demonstrated that, during a bloom of Trichodesmium spp., larvae of the prawn Penaeus merguiensis did not develop beyond the first protozoea stage, and survival was low compared with times when diatoms were dominant in
the same study area. Laboratory experiments confirmed the in situ results. None of the prawn larvae fed Trichodesmium sp. in laboratory experiments developed beyond the first protozoeal stage. In contrast, 94% of prawn larvae fed the green
flagellate Tetraselmis suecica successfully developed to the second protozoea stage. Electron microscopy of larvae gut-contents revealed that Trichodesmium spp. were ingested by larvae but were of no nutritional value, resulting in starvation. A 7 yr plankton survey, from 1985
to 1992, showed that minimum abundance of prawn larvae occurs during the annual summer blooms of Trichodesmium spp. and that maximum abundance of prawn larvae generally occurs just after the bloom. There was a negative correlation between
the abundance of larvae and the abundance of Trichodesmium at individual sites, one offshore and one inshore, indicating that the blooms affect the survival of larvae. We conclude that
variations in both timing and magnitude of Trichodesmium blooms are important determinants of prawn larvae abundance in Albatross Bay.
Received: 28 April 1997 / Accepted: 2 April 1998 相似文献
12.
The annual population dynamics (nauplii, old copepodites CIV–CV and adults) and seasonal variations in reproductive parameters
of the cyclopoid copepod Oithona similis were investigated on the basis of the data 1999–2006 in Kola Bay, a large subarctic fjord in the Barents Sea. Population
density of O. similis ranged from 110 to 9,630 ind m−3 and averaged 1,020 ± 336 ind m−3. The relative abundance of adults was high during winter (~60%). At the end of winter (mid-March), the population included
a large percentage of later-stage copepodites (stage CIV 23% and stage CV 57%). There were two periods of mass spawning, in
late June and September. Autumn and summer generations strongly differed in abundance, average prosome length (PL), clutch
size (CS), egg diameter (D), egg production rates (EPR and SEPR) and female secondary production. Average PL decreased with increasing water temperature,
while D and CS were strongly correlated with PL but unaffected by temperature. Annual average EPR and SEPR were 0.55 ± 0.18 eggs female−1 day−1 and 0.0011 ± 0.003 day−1, respectively. Female secondary production averaged 0.8 ± 0.3 μg C m−3 day−1 (range 0.001–3.58). There were positive relationships between abundance, EPR, SEPR, production and water temperatures. Reproductive
parameters appeared to be controlled by hydrological factors and food conditions. 相似文献
13.
Presence of Alexandrium catenella and paralytic shellfish toxins in finfish, shellfish and rock crabs in Monterey Bay, California, USA 总被引:1,自引:0,他引:1
The central California coast is a highly productive, biodiverse region that is frequently affected by the toxin-producing
dinoflagellate Alexandrium catenella. Despite the consistent presence of A. catenella along our coast, very little is known about the movement of its toxins through local marine food webs. In the present study,
we investigated 13 species of commercial finfish and rock crabs harvested in Monterey Bay, California for the presence of
paralytic shellfish toxins (PSTs) and compared them to the presence of A. catenella and PSTs in sentinel shellfish over a 3-year period. Between 2003 and 2005, A. catenella was noted in 55% of surface water samples (n = 307) and reached a maximum concentration of 17,387 cells L−1 at our nearshore site in Monterey Bay. Peak cell densities occurred in the month of July and were associated with elevated
shellfish toxicity in the summers of 2004 and 2005. When A. catenella was present, particulate PSTs were detected 71% of the time and reached a maximum concentration of 962 ng STXeq L−1. Of the 13 species tested, we frequently detected PSTs in Pacific sardines (Sardinops sagax; maximum 250 μg STXeq 100 g−1), northern anchovies (Engraulis mordax; maximum 23.2 μg STXeq 100 g−1), brown rock crabs (Cancer antennarius; maximum 49.3 μg STXeq 100 g−1) and red rock crabs (C. productus; 23.8 μg STXeq 100 g−1). PSTs were also present in one sample of Pacific herring (Clupea pallas; 13.3 μg STXeq 100 g−1) and one sample of English sole (Pleuronectes vetulus; 4.5 μg STXeq 100 g−1), and not detected in seven other species of flatfish tested. The presence of PSTs in several of these organisms reveals
that toxins produced by A. catenella are more prevalent in California food webs than previously thought and also indicates potential routes of toxin transfer
to higher trophic levels.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
Miriam Schutter Sander Kranenbarg René H. Wijffels Johan Verreth Ronald Osinga 《Marine Biology》2011,158(4):769-777
In this study, we tested the hypothesis that the importance of water flow for skeletal growth (rate) becomes higher with increasing
irradiance levels (i.e. a synergistic effect) and that such effect is mediated by a water flow modulated effect on net photosynthesis.
Four series of nine nubbins of G. fascicularis were grown at either high (600 μE m−2 s−1) or intermediate (300 μE m−2 s−1) irradiance in combination with either high (15–25 cm s−1) or low (5–10 cm s−1) flow. Growth was measured as buoyant weight and surface area. Photosynthetic rates were measured at each coral’s specific
experimental irradiance and flow speed. Additionally, the instantaneous effect of water flow on net photosynthetic rate was
determined in short-term incubations in a respirometric flowcell. A significant interaction was found between irradiance and
water flow for the increase in buoyant weight, the increase in surface area, and specific skeletal growth rate, indicating
that flow velocity becomes more important for coral growth with increasing irradiance levels. Enhancement of coral growth
with increasing water flow can be explained by increased net photosynthetic rates. Additionally, the need for costly photo-protective
mechanisms at low flow regimes could explain the differences in growth with flow. 相似文献
15.
Great scallop, Pecten maximus, and blue mussel, Mytilus edulis, clearance rate (CR) responses to low natural seston concentrations were investigated in the laboratory to study (1) short-term
CR variations in individual bivalves exposed to a single low seston diet, and (2) seasonal variations in average CR responses
of bivalve cohorts to natural environmental variations. On a short temporal scale, mean CR response of both species to 0.06 μg L−1 chlorophyll a (Chl a) and 0.23 mg L−1 suspended particulate matter (SPM) remained constant despite large intra-individual fluctuations in CR. In the seasonal study,
cohorts of each species were exposed to four seston treatments consisting of ambient and diluted natural seston that ranged
in mean concentration from 0.15 to 0.43 mg L−1 SPM, 0.01 to 0.88 μg L−1 Chl a, 36 to 131 μg L−1 particulate organic carbon and 0.019 to 0.330 mm3 L−1 particle volume. Although food abundance in all treatments was low, the nutritional quality of the seston was relatively
high (e.g., mean particulate organic content ranged from 68 to 75%). Under these low seston conditions, a high percentage
of P. maximus (81–98%) and M. edulis (67–97%) actively cleared particles at mean rates between 9 and 12 and between 4 and 6 L g−1 h−1, respectively. For both species, minimum mean CR values were obtained for animals exposed to the lowest seston concentrations.
Within treatments, P. maximus showed a greater degree of seasonality in CR than M. edulis, which fed at a relatively constant rate despite seasonal changes in food and temperature. P. maximus showed a non-linear CR response to increasing Chl a levels, with rates increasing to a maximum at approximately 0.4 μg L−1 Chl a and then decreasing as food quantity continued to increase. Mean CR of M. edulis also peaked at a similar concentration, but remained high and stable as the food supply continued to increase and as temperatures
varied between 4.6 and 19.6°C. The results show that P. maximus and M. edulis from a low seston environment, do not stop suspension-feeding at very low seston quantities; a result that contradicts previous
conclusions on the suspension-feeding behavior of bivalve mollusks and which is pertinent to interpreting the biogeographic
distribution of bivalve mollusks and site suitability for aquaculture. 相似文献
16.
In this study, juvenile colonies of massive Porites spp. (a combination of P. lutea and P. lobata) from the lagoon of Moorea (W 149°50′, S 17°30′) were damaged and exposed to contrasting conditions of temperature and flow
to evaluate how damage and abiotic conditions interact to affect growth, physiological performance, and recovery. The experiment
was conducted in April and May 2008 and consisted of two treatments in which corals were either undamaged (controls) or damaged
through gouging of tissue and skeleton in a discrete spot mimicking the effects of corallivorous fishes that utilize an excavating
feeding mode. The two groups of corals were incubated for 10 days in microcosms that crossed levels of temperature (26.7 and
29.6°C) and flow (6 and 21 cm s−1), and the response assessed as overall colony growth (change in weight), dark-adapted quantum yield of PSII (F
v/F
m), and healing of the gouged areas. The influence of damage on growth was affected by temperature, but not by flow. When averaged
across flow treatments, damage promoted growth by 25% at 26.7°C, but caused a 25% inhibition at 29.6°C. The damage also affected
F
v/F
m in a pattern that differed between flow speeds, with a 10% reduction at 6 cm s−1, but a 4% increase at 21 cm s−1. Regardless of damage, F
v/F
m at 21 cm s−1 was 11% lower at 26.7°C than at 29.6°C, but was unaffected by temperature at 6 cm s−1. The lesions declined in area at similar rates (4–5% day−1) under all conditions, although the tissue within them regained a normal appearance most rapidly at 26.7°C and 6 cm s−1. These findings show that the response of poritid corals to sub-lethal damage is dependent partly on abiotic conditions,
and they are consistent with the hypothesis that following damage, calcification and photosynthesis can compete for metabolites
necessary for repair, with the outcome affected by flow-mediated mass transfer. These results may shed light upon the ways
in which poritid corals respond to biting by certain corallivorous fishes. 相似文献
17.
Glenn Lurman Till Blaser Miles Lamare Koh-Siang Tan Hans Poertner Lloyd S. Peck Simon A. Morley 《Marine Biology》2010,157(8):1705-1712
Temperature and mitochondrial plasticity are well studied in fishes, but little is known about this relationship in invertebrates.
The effects of habitat temperature on mitochondrial ultrastructure were examined in three con-familial limpets from the Antarctic
(Nacella concinna), New Zealand (Cellana ornata), and Singapore (Cellana radiata). The effects of seasonal changes in temperature were also examined in winter and summer C. ornata. Stereological methods showed that limpet pedal myocytes were 1–2 orders of magnitude smaller in diameter (≈3.5 μm) than
in vertebrates, and that the diameter did not vary as a function of temperature. Mitochondrial volume density (Vv(mt,f)) was approximately 2–4 times higher in N. concinna (0.024) than in the other species (0.01 and 0.006), which were not significantly different from each other. Mitochondrial
cristae surface density (Sv(im,mt)) was significantly lower in summer C. ornata (24.1 ± 0.50 μm2 μm−3) than both winter C. ornata (32.3 ± 0.95 μm2 μm−3) and N. concinna (34.3 ± 4.43 μm2 μm−3). The surface area of mitochondrial cristae per unit fibre volume was significantly higher in N. concinna, due largely to the greater mitochondrial volume density. These results and previous studies indicate that mitochondrial
proliferation in the cold is a common, but not universal response by different species from different thermal habitats. Seasonal
temperature decreases on the other hand, leading preferentially to an increase in cristae surface density. Stereological measures
also showed that energetic reserves, i.e. lipid droplets and glycogen in the pedal muscle changed greatly with season and
species. This was most likely related to gametogenesis and spawning. 相似文献
18.
Katsutoshi Ito Mana Nozaki Takashi Ohta Chiemi Miura Yuzuru Tozawa Takeshi Miura 《Marine Biology》2011,158(6):1211-1221
Polychaetes constitute most of the benthic macroinvertebrates in estuarine and coastal environments. We investigated the utilization
of organic matter in two polychaete species, Capitella sp. I and Perinereis nuntia brevicirris, living in different coastal habitats. The protease activity of Capitella sp. I (89.7 μg mg−1) was about 10 times that of P. nuntia brevicirris (8.0 μg mg−1). High cellulase (endo-β-1,4-glucanase) activity was detected in P. nuntia brevicirris (3.2 μg mg−1), whereas scarcely any was detected in Capitella sp. I. We isolated cDNA clones of protease mRNA from Capitella sp. I and of cellulase mRNA from P. nuntia brevicirris. The high protease activity of Capitella sp. I enabled it to survive in the sediment under a fish farm, where it degrades organic matter. In contrast, the high cellulase
activity of the estuary-dwelling P. nuntia brevicirris allowed it to degrade organic matter originating from terrestrial areas. 相似文献
19.
Phytoaccumulation prospects of cadmium and zinc by mycorrhizal plant species growing in industrially polluted soils 总被引:2,自引:0,他引:2
The natural vegetation growing along a wastewater channel was subjected to analyze the uptake of Cadmium (Cd) and Zinc (Zn)
and their subsequent accumulation in aboveground and underground plant parts. Species which were mycorrhizal and growing in
soils receiving industrially contaminated wastewater were collected along with their rhizospheric soil samples. The nearby
uncontaminated control (reference) area was also subjected to sampling on similar pattern for comparison. Both Cd and Zn concentrations
were significantly higher in soils of the study area as compared to the reference site. Five plant species i.e. Desmostachya bipinnata, Dichanthium annulatum, Malvastrum coromandelianum, Saccharum bengalense, and Trifolium alexandrinum were analyzed for metal uptake. The maximum phytoaccumulation of Cd was observed in Desmostachya bipinnata (20.41 μg g−1) and Dichanthium annulatum (15.22 μg g−1) for shoot and root tissues, respectively. However, Malvastrum coromandelianum revealed maximum Zn accumulation for both the shoot and the root tissues (134 and 140 μg g−1, respectively). The examination of cleared and stained roots of the plants from both the areas studied revealed that all
of them were colonized to a lesser or a greater degree by arbuscular mycorrhizal (AM) fungi. The Cd hyperaccumulating grasses
i.e. Desmostachya bipinnata and Dichanthium annulatum, from study area had smaller root:shoot (R/S) ratio as compared to those growing on reference area indicating a negative
pressure of soil metal contamination. The lower R/S ratio in the mycorrhizal roots observed was probably due to increased
AM infection and its mediatory role in soil plant transfer of heavy metals. Furthermore, comparatively lower soil pH values
in the study areas may have played a key role in making the overall phytoavailability of both the metals. Consequently variations
in Cd and Zn tissue concentration among species were observed that also indicate the phytoaccumulation potential of the native
species. 相似文献
20.
The transport of eel early life stages may be critical to their population dynamics. This transport from ocean spawning to
freshwater, estuarine and coastal nursery areas is a combination of physical and biological processes (including swimming
behavior). In New Jersey, USA, the American eel (Anguilla rostrata) enters estuaries as glass eels (48.7–68.1 mm TL) in contrast to the Conger eel (Conger oceanicus) that enters as larger (metamorphosing) leptocephali (68.3–117.8 mm TL). To begin to understand the mechanisms of cross-shelf
transport for these species, we measured the potential swimming capability (critical swimming speed, U
crit) under ambient conditions throughout the ingress season. A. rostrata glass eels were collected over many months (January–June) at a range of temperatures (4–21°C), with relative condition declining
over the course of the ingress period as temperatures warmed. C. oceanicus occurred later in the season (April–June) and at warmer temperatures (14–24.5°C). Mean U
crit values for A. rostrata (11.7–13.3 cm s−1) and C. oceanicus (14.7–18.6 cm s−1) were comparable, but variable, with portions of the variability explained by water temperature, relative condition, ontogenetic
stage, and fish length. Travel times to Little Egg Inlet, New Jersey, estimated using 50% U
crit values, indicate it would take A. rostrata ~30 and ~60 days to swim from the shelf edge and Gulf Stream, respectively. Travel times for C. oceanicus were shorter, ~20 days from the shelf edge, and ~45 days from the Gulf Stream. Despite differences in life stage, our results
indicate both species are competent swimmers, and suggest they are capable of swimming from the Gulf Stream and/or edge of
the continental shelf to estuarine inlets. 相似文献