共查询到20条相似文献,搜索用时 78 毫秒
1.
We examined the respiration rate of Aurelia aurita medusae at 20 °C and 28 °C to evaluate minimum metabolic demands of medusae population in Sihwa Lake, Korea during summer. While weight specific respiration rates of medusae were constant and irrespective to the wet weight (8?C220 g), they significantly varied in respect to temperatures (p<0.001, 0.11±0.03 mg C g?1 of medusa d?1 at 20°C and 0.28±0.11 mg C g?1 of medusa d?1 at 28 °C in average, where Q 10 value was 2.62). The respiration rate of medusae was defined as a function of temperature (T, °C) and body weight (W, g) according to the equation, R=0.13×2.62(T-20)/10 W 0.93. Population minimum food requirement (PMFR) was estimated from the respiration rate as 15.06 and 4.86 mg C m?3 d?1 in June and July, respectively. During this period, increase in bell diameter and wet weight was not significant (p=1 in the both), suggesting that the estimated PMFR closely represented the actual food consumption in the field. From July to August, medusae grew significantly at 0.052 d-1, thus the amount of food ingested by medusae population in situ was likely to exceed the PMFR (1.27 mg C m?3 d?1) during the period. In conclusion, the medusae population of higher density during June and July had limited amount of food, while those of lower in July and August ingested enough food for growth. 相似文献
2.
The abundance of a scyphomedusae, Aurelia aurita and Chrysaora melanaster, and a ctenophore, Bolinopsis mikado, in Tokyo Bay was investigated from 1995 to 1997. Aurelia aurita appeared throughout the year with a peak in abundance occurring from spring to summer. The average abundance and biomass
during this period for the three successive years was 4.8, 43.8 and 3.2 ind. m−2, and 1.02, 10.0 and 0.42 gC m−2, respectively. The values in 1995 and 1997 were comparable with those previously reported for A. aurita abundance from 1990 to 1992. Values were very high in 1996, but the size composition of the bell diameter did not differ
from other years, which suggested the absence of food limitation for A. aurita in 1996. C. melanaster was scarce over the survey period (<1.0 ind. m−2) while Bolinopsis mikado was more abundant during September to December, with maximum values of 172 ind. m−2 and 0.33 gC m−2 observed in December 1997. The weight-specific clearance rate for A. aurita on zooplankton (mainly copepods and their nauplii) was 0.16 ± 0.05 lgWW−1 h−1 (n = 13). Population clearance rate peaked from spring to summer, with average levels of 14.2%, 162% and 5.0% day−1 obtained from spring to summer for respective years. Population clearance rates for B. mikado, calculated based on minimum carbon requirements, was 7.1% day−1 in December 1997. Consequently, the trophic role of gelatinous zooplankton as predators in Tokyo Bay is important all the
year round, considering the high impact of A. aurita from spring to summer and B. mikado from autumn to winter. 相似文献
3.
The seasonal abundance of the dominant dinoflagellate, Ceratium fusus, was investigated from January 2000 to December 2003 in a coastal region of Sagami Bay, Japan. The growth of this species
was also examined under laboratory conditions. In Sagami Bay, C. fusus increased significantly from April to September, and decreased from November to February, though it was found at all times
through out the observation period. C. fusus increased markedly in September 2001 and August 2003 after heavy rainfalls that produced pycnoclines. Rapid growth was observed
over a salinity range of 24 to 30, with the highest specific rate of 0.59 d−1 measured under the following conditions: salinity 27, temperature 24°C, photon irradiance 600 μmol m−2s−1. The growth rate of C. fusus increased with increasing irradiance from 58 to 216 μmol m−2s−1, plateauing between 216 and 796 μmol m−2s−1 under all temperature and salinity treatments (except at a temperature of 12°C). Both field and laboratory experiments indicated
that C. fusus has the ability to grow under wide ranges of water temperatures (14–28°C), salinities (20–34), and photon irradiance (50–800
μmol m−2s−1); it is also able to grow at low nutrient concentrations. This physiological flexibility ensures that populations persist
when bloom conditions come to an end. 相似文献
4.
Jonathan M. Shenker 《Estuarine, Coastal and Shelf Science》1984,19(6):619-632
The scyphomedusae of the surface waters off Oregon and southern Washington were collected with commercial purse seines from May–August 1981. Twelve east-west transects, located from north of the Columbia River to south of Coos Bay were sampled from the 37 m isobath to distances up to 48 km from shore. Chrysaora fuscescens was the dominant species collected in each month. Maximum sampled abundances reached 18001 of medusae per 105 m3. Using an estimated carbon content of 0·280% of wet weight, this medusa density was calculated to contain approximately 50 mg Cm−3. Seven of the 263 samples contained so many medusae that they exceeded the capacity of the sampling gear. In all months but May, when medusa densities were relatively low, the density of C. fuscescens was greatest closest to shore and decreased rapidly offshore. Mean umbrella diameter increased from 8·6 cm in May to 18·5 cm in August, while the largest specimens increased from 19 cm in May to 37 cm in August. Aurelia aurtia, Cyanea capillata and Phacellophora camtschatica were also collected, but were much less abundant than C. fuscescens. The relative abundance of C. fuscescens was compared with the maximum abundance of copepods off the Oregon coast, and the hydrographic features influencing medusa distribution patterns are discussed. 相似文献
5.
There is the natural habitat of polyps of the common jellyfish Aurelia aurita in the Taniyama area, Kagoshima Bay. We examined the attachment substrata, density, colony structure and strobilation of
the polyps. The polyps were observed only on the horizontal undersurface of floating piers. They attached specifically to
Mytilus shells, solitary ascidians, calcareous polychaete tubes, muddy amphipod tubes and the gap space that fouling animals peeled
off the substrata. The polyp colonies were distributed in patches. Spatial distribution patterns of the polyps within their
colonies were uniform. Strobilation occurred during late December to March, when water temperatures were 16–17°C, and a large
number of ephyrae were released. An increase in man-made structures such as floating piers in coastal areas may lead to bloomings
of Aurelia aurita medusae.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Tsutomu Ikeda 《Journal of Oceanography》1989,45(3):167-173
Whole animal respiration rates (R) of myctophid fishes which migrate up to the surface at night were estimated using enzyme activities of the electron-transport-system (ETS). The fish, currently unsusceptible to laboratory experimentation, were caught at sea and stored frozen at –20°C for 14–17 days prior to enzyme assay. Supplemental tests on two tropical marine fishes (gobies and poma-centrids) showed no measurable loss of ETS activity during storage for up to 36 d at –20°C. The ETS/R ratio for gobies and pomacentrids was 1.61. Respiration rates of myctophid fishes estimated using this ETS/R ratio ranged from 17.7 to 453µl O2 individual–1 hr–1 for specimens weighing 26–1101 mg wet weight atin situ temperature of 24–27°C. The relationship between the respiration rate standardized to a temperature of 20°C (R:µl O2 individual–1hr–1) and wet weight (WW: mg) of myctophid fishes was expressed asR=0.790 WW0.84 (r=0.964,n=27). This relationship does not differ appreciably from the respiration rates of other marine fishes calculated from Winberg's equation. 相似文献
7.
The Kuroshio near the Luzon Strait and circulation in the northern South China Sea during August and September 1994 总被引:3,自引:0,他引:3
Wind data from NCEP and hydrographic data obtained from August 28 to September 10, 1994 have been used to compute circulation
in the northern South China Sea and near Luzon Strait using three-dimensional diagnostic models with a modified inverse method.
The numerical results are as follows: the main Kuroshio is located above 400 m levels near Taiwan’s eastern coast and above
800 m levels away from it. Near Luzon Strait above 400 m levels a branch of the Kuroshio joins with a part of the northward
current, which comes from an area west of Luzon’s western coast and intrudes northwestward, then it branchs into western and
eastern parts near 20°30′ N. The eastern part flows northward into an area east of Taiwan, while its western part continues
to intrude northwestward, flowing through an area southwest of Taiwan. Net westward intruded volume transport through longitude
Section AB at 121°00′ E from 19°00′ N to 21° 43′ N is about 3.5 × 106 m3s−1 in a layer above 400 m levels. The anticyclonic eddies W1 and W3 exist above 700 m levels east of Dongsha Islands and below
200 m levels in the eastern part of the region, respectively. The circulation in the middle region is dominated mainly by
a basin-scale cyclonic gyre, and consists of three cyclonic eddies. Strong upwelling occurs in the middle region. The joint
effect of baroclinity and relief and interaction between wind stress and relief both are important for real forcing of flow
across contours of fH
−1 in effecting the circulation pattern. 相似文献
8.
Tsutomu Ikeda 《Journal of Oceanography》2011,67(6):785-790
This study demonstrates reduced electron transfer system (ETS) activity of mixed copepods collected from 5,000 to 7,000 m
depths [3.21 ± 1.25 μl O2 (mg protein)−1 h−1 at 10°C] as compared with mixed copepods from 0 to 200 m depths [5.93 ± 1.66 μl O2 (mg protein)−1 h−1 at 10°C] of the western subarctic Pacific. At the in situ temperature of 1.5°C, the 5,000–7,000 m ETS data, in terms of wet
mass (WM)-specific respiration rates (R), is equivalent to [0.052 ± 0.021 μl O2 (mg WM)−1 h−1] which is similar to or greater than those reported for selected copepods or mixed mesozooplankton from <5,000 m depth by
previous workers. 相似文献
9.
A matter of tolerance: Distribution potential of scyphozoan polyps in a changing environment
下载免费PDF全文
![点击此处可从《Marine Ecology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jellyfish blooms are unpredictable, unsustainable events, frequently affecting aquatic ecosystems severely. Of particular interest are the consequences of environmental change for jellyfish populations, especially in semi‐enclosed habitats. Regional and seasonal changes in water chemistry and physics may control the distribution of sessile polyps in the Baltic Sea, hence potentially driving the population dynamics of the two abundant medusa species Aurelia aurita and Cyanea capillata (Scyphozoa, Cnidaria). In laboratory experiments, settlement, growth, survival and physiological condition of A. aurita polyps were investigated at different levels of water temperature, pH and salinity. Survival and physiological condition of C. capillata polyps were examined after exposure to low salinity levels. Increased settlement of A. aurita planula larvae was observed on substrate plates at low temperature (4°C), low pH (7.4) and low salinity (7.5 psu), whereas early polyp growth was constrained by salinity ≤10 psu. Aurelia aurita polyps were in good physiological condition over the whole temperature range, while exposure to pH <6.5 led to stepwise tissue degradation. Salinity reduction to ≤5 and ≤8 psu caused irreversible degeneration of A. aurita and C. capillata polyps, respectively. Observed physiological limits suggest distribution of polyp populations of A. aurita in central and of C. capillata in western parts of the Baltic Sea, while future climate changes may particularly restrict occurrence of the less tolerant C. capillata. 相似文献
10.
Minoru Fujii Shinichiro Murashige Yuka Ohnishi Atushi Yuzawa Hitoshi Miyasaka Yoshimi Suzuki Hiroshi Komiyama 《Journal of Oceanography》2002,58(3):438-443
Decomposition experiments were conducted on cultured phytoplankton (Skeletonema costatum) in seawater containing decomposer and consumer of size less than 500 μm. We determined the decomposition rates of bulk particulate
organic matter (POM), the ratio of labile to semi-refractory fractions in the POM, and the POM carbon/ nitrogen (C/N) ratio
during decomposition. To identify the kinetic mechanisms involved in the reactions of different order (e.g., first- and second-order),
we studied the sensitivity of reaction rates to the initial concentration of POM, ranging from 2.4 to 71 mg-C L−1. The results showed that decomposition consists of two first-order reactions: decomposition of labile and of semi-refractory
particulate organic carbon (POC). The decomposition rate constants found for labile (0.13 day−1 at 20°C), and semi-refractory POC (0.008 day−1 at 20°C), and the carbon weight ratio of semi-refractory POC (13% at 20°C), were insensitive to the initial organic matter
concentration. The time-dependence of the C/N ratio was also independent of this initial concentration. The decomposition
rate constants and the content of semi-refractory POC did not change, regardless of the absence or presence of 25–500 μm organisms
in natural seawater.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
Spatial Variability of Living Coccolithophore Distribution in the Western Subarctic Pacific and Western Bering Sea 总被引:1,自引:0,他引:1
Hiroshi Hattori Makoto Koike Kenichi Tachikawa Hiroaki Saito Kazuya Nagasawa 《Journal of Oceanography》2004,60(2):505-515
Vertical distributions of coccolithophores were observed in the depth range 0–50 m in the western subarctic Pacific and western
Bering Sea in summer, 1997. Thirty-five species of coccolithophores were collected. Overall, Emiliania huxleyi var. huxleyi was the most abundant taxon, accounting for 82.8% of all coccolithophores, although it was less abundant in the western Bering
Sea. Maximum abundance of this species was found in an area south of 41°N and east of 175°E (Transition Zone) reaching >10,000
cells L−1 in the water column. In addition to this species, Coccolithus pelagicus f. pelagicus, which accounted for 4.2% of the assemblage, was representative of the coccolithophore standing crop in the western part
of the subarctic Pacific. Coccolithus pelagicus f. hyalinus was relatively abundant in the Bering Sea, accounting for 2.6% of the assemblage. Coccolithophore standing crops in the top
50 m were high south of 41°N (>241 × 106 cells m−2) and east of 170°E (542 × 106 cells m−2) where temperatures were higher than 12°C and salinities were greater than 34.2. The lowest standing crop was observed in
the Bering Sea and Oyashio areas where temperatures were lower than 6–10°C and salinities were less than 33.0. From the coccolithophore
volumes, the calcite stocks in the Transition, Subarctic, and the Bering Sea regions were estimated to be 73.0, 9.7, and 6.9
mg m−2, respectively, corresponding to calcite fluxes of 3.6, 0.5, and 0.3 mg m−2d−1 using Stoke's Law.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Prey selection and knowledge of the amounts of water processed by the early stages of the common jellyfish Aurelia aurita may at certain times of the year be crucial for understanding the plankton dynamics in marine ecosystems with mass occurrences of this jellyfish. In the present study we used two different methods (“clearance method” and “ingestion-rate method”) to estimate the amount of water cleared per unit of time of different types and sizes of prey organisms offered to A. aurita ephyrae and small medusae. The mean clearance rates of medusae, estimated with Artemia sp. nauplii as prey by both methods, agreed well, namely 3.8 ± 1.4 l h? 1 by the clearance method and 3.2 ± 1.1 l h? 1 by the ingestion-rate method. Both methods showed that copepods (nauplii and adults) and mussel veligers are captured with considerably lower efficiency, 22 to 37% and 14 to 30%, respectively, than Artemia salina nauplii. By contrast, the water processing rates of ephyrae measured by the clearance method with A. salina nauplii as prey were 3 to 5 times lower than those measured by the ingestion-rate method. This indicates that the prerequisite of full mixing for using the clearance method may not have been fulfilled in the ephyrae experiments. The study demonstrates that the predation impact of the young stages of A. aurita is strongly dependent on its developmental stage (ephyra versus medusa), and the types and sizes of prey organisms. The estimated prey-digestion time of 1.3 h in a steady-state feeding experiment with constant prey concentration supports the reliability of the ingestion-rate method, which eliminates the negative “container effects” of the clearance method, and it seems to be useful in future jellyfish studies, especially on small species/younger stages in which both type and number of prey can be easily and precisely assessed. 相似文献
13.
《African Journal of Marine Science》2013,35(1):523-529
Feeding periodicity, consumption rate, absorption efficiency, respiration rate and ammonia excretion were measured as functions of wet body mass in abalone collected from the western and southern Cape coasts. A well developed diel feeding rhythm was evident, consumption being restricted to the period 16h00–08h00. Food intake averaged 8,1 per cent of wet flesh mass·d?1 at 14°C and 11,4 percent at 19°C. The daily consumption rate was related to body mass by the relationships C(g) = 0,54 W(g)0,67 at 14°C and C(g) = 0,35 W(g)0,77 at 19°C. Absorption efficiency averaged 37 per cent and was independent of body size. Equations relating respiration rate to wet body mass were R(m? O2·h?1) = 0,03 W(g)0,83 at 14°C and R = 0,03 W(g)0,94 at 19°C. No significant differences were detected between day and night rates or between fed and starved individuals. The rate of ammonia excretion (μmole·h?1) was related to wet body mass (g) by the equations U = 0,22 W0,43 at 14°C and U = 0,03 W0,85 at 19°C. 相似文献
14.
《African Journal of Marine Science》2013,35(3):391-399
Rates of respiration and ammonia excretion of Euphausia hanseni and Nematoscelis megalops were determined experimentally at four temperatures representative of conditions encountered by these euphausiid species in the northern Benguela upwelling environment. The respiration rate increased from 7.7 µmol O2 h?1 gww ?1 at 5 °C to 18.1 µmol O2 h?1 gww ?1 at 20 °C in E. hanseni and from 7.0 µmol O2 h?1 gww ?1 (5 °C) to 23.4 µmol O2 h?1 gww ?1 (20 °C) in N. megalops. The impact of temperature on oxygen uptake of the two species differed significantly. Nematoscelis megalops showed thermal adaptations to temperatures between 5 °C and 10 °C (Q10 = 1.9) and metabolic constraint was evident at higher temperatures (Q10 = 2.6). In contrast, E. hanseni showed adaptations to temperatures of 10–20 °C (Q10 = 1.5) and experienced metabolic depression below 10 °C (Q10 = 2.6). Proteins were predominantly metabolised by E. hanseni in contrast to lipids by N. megalops. Carbon demand of N. megalops between 5 and 15 °C was lower than in E. hanseni versus equal food requirements at 20 °C. It is concluded that the two species display different physiological adaptations, based on their respective temperature adaptations, which are mirrored in their differential vertical positioning in the water column. 相似文献
15.
Hodaka Kawahata Mayuri Inoue Masato Nohara Atsushi Suzuki 《Journal of Oceanography》2006,62(4):405-412
The δ18O, δ13C and trace element composition of pearls collected from Ago Bay, Japan, were investigated in order to evaluate biomineralization
in the cultured pearl oyster (Pinctada fucata martensii). The oxygen isotopic data suggest that the pearls were produced around 23–24°C, mainly in June to early July, which is consistent
with their occurrence in the field. Therefore the pearls were produced under or close to isotopic equilibrium conditions,
although they showed high calcification rates (higher than 0.2–1.0 g cm− 2yr−1) under which, for example, coral skeletons (calcification rate ∼0.28 g cm− 2yr−1) often show non-equilibrium isotope partitioning. The δ13C values were ∼− 2.9‰ lower than those calculated for offshore waters under equilibrium conditions. This may be due to low-δ13C bottom waters resulting from the degradation of organic matter (OM) or to a contribution of low-δ 13C food. In the latter case, a simple mass balance calculation gives a respiration component of 14%. Twelve trace elements
of bulk pearl samples were classified into four groups on the basis of their enrichment/depletion patterns relative to seawater
and inter-element relationships: group 1, Co, Cr, Pb; group 2, Ba, Cs, U; group 3, Cu, Sn, V, and group 4, Mn, Rb, Mo. Comparison
with coral skeletons suggests that Ba and Mn (groups 2 and 4) were definitely much enriched in proteinaceous OM relative to
aragonite crystals in pearls and that V (group 3) in pearls showed only slight enrichment in the organicrich layer. By contrast,
the other elements showed small differences between both layers (enrichment factor of <3), suggesting that these elements
occur largely in aragonite crystals. 相似文献
16.
Tomoyuki Shikata Sou Nagasoe Tadashi Matsubara Yasuhiro Yamasaki Yohei Shimasaki Yuji Oshima Takuji Uchida Ian R. Jenkinson Tsuneo Honjo 《Journal of Oceanography》2008,64(3):355-365
In the present study, we have investigated the conditions influencing encystment and excystment in the dinoflagellate Gyrodinium instriatum under laboratory conditions. We incubated G. instriatum in modified whole SWM-3 culture medium and in versions of modified SWM-3 from which NO3
−, PO4
3−, NO3
− + PO4
3−, or Si had been omitted and observed encystment. Percentage encystment was high in the media without N and without P, while
the percentage encystment in the medium lacking both N and P was highest. Moreover, to investigate N or P concentration which
induced the encystment, Gyrodinium instriatum was also incubated in media with different concentrations of inorganic N and P; the concentrations of NO2
− + NO3
− and PO4
3− were measured over time. The precursors of cysts appeared within 2 or 3 days of a decrease in NO2
− + NO3
− or PO4
3− concentration to values lower than 1 μM or 0.2 μM, respectively. When cysts produced in the laboratory were incubated, we observed excystment after 8–37 days, without a mandatory
period of darkness or low temperature. We incubated cysts collected from nature at different temperatures or in the dark or
light and observed excystments. Natural cysts excysted at temperatures from 10 to 30°C, in both light and dark, but excystment
was delayed at low temperatures. These studies indicate that G. instriatum encysts in low N or P concentration and excysts over a wide temperature range, regardless of light conditions, after short
dormancy periods. 相似文献
17.
We utilized 234Th, a naturally occurring radionuclide, to quantify the particulate organic carbon (POC) export rates in the northern South
China Sea (SCS) based on data collected in July 2000 (summer), May 2001 (spring) and November 2002 (autumn). Th-234 deficit
was enhanced with depth in the euphotic zone, reaching a subsurface maximum at the Chl-a maximum in most cases, as commonly
observed in many oceanic regimes. Th-234 was in general in equilibrium with 238U at a depth of ∼100 m, the bottom of the euphotic zone. In this study the 234Th deficit appeared to be less significant in November than in July and May. A surface excess of 234Th relative to 238U was found in the summer over the shelf of the northern SCS, most likely due to the accumulation of suspended particles entrapped
by a salinity front. Comparison of the 234Th fluxes from the upper 10 m water column between 2-D and traditional 1-D models revealed agreement within the errors of
estimation, suggesting the applicability of the 1-D model to this particular shelf region. 1-D model-based 234Th fluxes were converted to POC export rates using the ratios of bottle POC to 234Th. The values ranged from 5.3 to 26.6 mmol C m−2d−1 and were slightly higher than those in the southern SCS and other oligotrophic areas. POC export overall showed larger values
in spring and summer than in autumn, the seasonality of which was, however, not significant. The highest POC export rate (26.6
mmol C m−2d−1) appeared at the shelf break in spring (May), when Chl-a increased and the community structure changed from pico-phytoplankton
(<2 μm) dominated to nano-phytoplankton (2–20 μm) and micro-phytoplankton (20–200 μm) dominated. 相似文献
18.
Vibrio parahaemolyticus is a common pathogenic bacterium in marine and estuarine waters. To investigate interactions between V. parahaemolyticus and co-occurring redtide dinoflagellates, we monitored the daily abundance of 5 common red tide dinoflagellates in laboratory
culture; Amphidinium carterae, Cochlodinium ploykrikoides, Gymnodinium impudicum, Prorocentrum micans, and P. minimum. Additionally, we measured the ingestion rate of each dinoflagellate on V. parahaemolyticus as a function of prey concentration. Each of the dinoflagellates responded differently to the abundance of V. parahaemolyticus. The abundances of A. carterae and P. micans were not lowered by V. parahaemolyticus, whereas that of C. polykrikodes was lowered considerably. The harmful effect depended on bacterial concentration and incubation time. Most C. polykrikoides cells died after 1 hour incubation when the V. parahaemolyticus concentration was 1.4×107 cells ml−1, while cells died within 2 days of incubation when the bacterial concentration was 1.5×106 cells ml−1. With increasing V. parahaemolyticus concentration, ingestion rates of P. micans, P. minimum, and A. carterae on the prey increased, whereas that on C. polykrikoides decreased. The maximum or highest ingestion rates of P. micans, P. minimum, and A. carterae on V. parahaemolyticus were 55, 5, and 2 cells alga−1 h−1, respectively. The results of the present study suggest that V. parahaemolyticus can be both the killer and prey for some red tide dinoflagellates. 相似文献
19.
Daily rates of gross primary production, net community production and community respiration were determined in spring of 1997
at two stations in a warm streamer off Sanriku, Japan fromin vitro changes in dissolved oxygen. The phytoplankton community was composed of chlorophytes, cryptophytes and prymnesiophytes as
determined by biomarker pigment analysis. Gross production, integrated from the surface to its 1% light level was 52.5 and
80.4 mmol O2 m−2d−1. The difference in gross production is ascribed to variations in photosynthetic activity of the population. Community respiration
was 17.4 and 49.5 mmol O2 m−2d−1, and positive net community production was found within the euphotic zone. The contribution of autotrophic and heterotrophic
respiration to community respiration was estimated on the basis of the observed respiration and the phytoplankton composition.
Heterotrophic respiration was calculated to be highly variable and the observed difference in community respiration was due
to heterotrophic respiration. Heterotrophic respiration was considered to play an important role in the rapid mineralization
of organic materials. 相似文献
20.
Effects of cold eddy on phytoplankton production and assemblages in Luzon strait bordering the South China Sea 总被引:6,自引:0,他引:6
Yuh-Ling Lee Chen Houng-Yung Chen I. -I. Lin Ming-An Lee Jeng Chang 《Journal of Oceanography》2007,63(4):671-683
The biochemical effects of a cold-core eddy that was shed from the Kuroshio Current at the Luzon Strait bordering the South
China Sea (SCS) were studied in late spring, a relatively unproductive season in the SCS. The extent of the eddy was determined
by time-series images of SeaWiFS ocean color, AVHRR sea surface temperature, and TOPEX/Jason-1 sea surface height anomaly.
Nutrient budgets, nitrate-based new production, primary production, and phytoplankton assemblages were compared between the
eddy and its surrounding Kuroshio and SCS waters. The enhanced productivity in the eddy was comparable to wintertime productivity
in the SCS basin, which is supported by upwelled subsurface nitrate under the prevailing Northeastern Monsoon. There were
more Synechococcus, pico-eucaryotes, and diatoms, but less Trichodesmium in the surface water inside the eddy than outside. Prochlorococcus and Richelia intracellularis showed no spatial differences. Water column-integrated primary production (IPP) inside the eddy was 2–3 times that outside
the eddy in the SCS (1.09 vs. 0.59 g C m−2d−1), as was nitrate-based new production (INP) (0.67 vs. 0.25 g C m−2d−1). INP in the eddy was 6 times that in the Kuroshio (0.12 g C m−2d−1). IPP and INP in the eddy were higher than the maximum production values ever measured in the SCS basin. Surface chlorophyll
a concentration (0.40 mg m−3) in the eddy equaled the maximum concentration registered for the SCS basin and was higher than the wintertime average (0.29
± 0.04 mg m−3). INP was 3.5 times as great and IPP was doubled in the eddy compared to the wintertime SCS basin. As cold core eddies form
intermittently all year round as the Kuroshio invades the SCS, their effects on phytoplankton productivity and assemblages
are likely to have important influences on the biogeochemical cycle of the region. 相似文献