scholarly journals FATE OF SEAGRASS PRODUCTION AS ASSESSED BY CAGE EXPERIMENTS IN Enhalus Acoroides BED IN GILIMANUK BAY, BALI, INDONESIA

2008 ◽  
Vol 33 (2) ◽  
pp. 109-113
Author(s):  
M. Husni Azkab
Keyword(s):  
Seagrass Meadow ◽  
Dry Weight ◽  
Seagrass Bed ◽  
Enhalus Acoroides

In 2006, the amounts of seagrass products floating away and depositing were measured by in situ cage experiments in a monospecific seagrass meadow of Enhalus acoroides in Gilimanuk Bay, Bali Island. Results showed that the average rates of the floating and depositing leaves were 4.03 + 0.28 and 7.95 + 0.31 gram dry weight shoot-1 day-1 respectively. To express it in another way, about 66.4 % of seagrass production was deposited on the seagrass bed and 33.6 % floated away from the seagrass bed.

Assessing Soil and Plant Pollution by Abandoned Rural Waste Dumping Sites in Ningbo, China

2011 ◽  
Vol 138-139 ◽  
pp. 1149-1155 ◽  
Author(s):  
Yi Dong Guan ◽  
Ye Hong Du ◽  
Zhen Dong Li ◽  
An Cheng Luo
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Reference Value ◽  
Dry Weight ◽  
Rice Grain ◽  
Contamination Assessment ◽  
Plant Parts ◽  
Metal Contents ◽  
Plant Pollution

This paper reports the concentration of heavy metals (Cr, Cu, Zn, Cd and Pb) in the soils and rices surrounding the abandoned rural waste dumping sites in Ningbo. Igeo (geoaccumulation index) was calculated to assess the contamination degree of heavy metals in soils. The mean contents of Cr, Cu, Cd, Zn and Pb of soils were 33.3, 24.1, 1.5, 118.9 and 45.6 mg/(kg DW) (dry weight), respectively. All of them were much higher than that of the reference value (i.e. CK), but there were no coherent trend of the metal contents within 1-120m distance from the dumping site. Igeo of heavy metals reveals the order of Cd>Cu>Cr>Pb>Zn, and the contamination assessment of soils using Igeo indicate the moderate Cd pollution, while the soils were unpolluted-moderately overall by Cr, Cu, Zn as well as Pb. The heavy metal contents in root, stem & leaf and rice grains were all remarkable higher than that of the CK at 20-120 m distances, and the heavy metal contents in root were evidently much higher than other plant parts, while those in rice grain were lowest, indicating the great bioaccumulation trend of heavy metals. Although the metal contents in the rice grain were within the legislation limit, its bioaccumulation trend of heavy metals was remarkable, whose contents were 4.38-fold for Cr, 1.76-fold for Cu, 1.28-fold for Zn, 2.67-fold for Cd and 3.03-fold for Pb higher than that of reference value, respectively. Finally, we proposed a decentralized in-situ restoration approach for the dumping sites.

scholarly journals Intra and inter annual variation in a seagrass meadow on the Caribbean coast of Costa Rica: 2009-2015

2018 ◽  
Vol 66 (3) ◽  
pp. 1149 ◽  
Author(s):  
Margarita Loría-Naranjo ◽  
Jimena Samper-Villarreal ◽  
Marylaura Sandoval-Siles ◽  
Jorge Cortés
Keyword(s):  
Costa Rica ◽  
Leaf Area ◽  
Turnover Rate ◽  
Seagrass Meadow ◽  
Seagrass Beds ◽  
Seagrass Bed ◽  
Monitoring Methods ◽  
Caribbean Coast ◽  
Area Index ◽  
The Caribbean

Seagrass beds are an important ecosystem on the Caribbean coast of Costa Rica. At Cahuita National Park (CNP) a seagrass bed at Perezoso has been monitored continually since 1999 within the CARICOMP program. Thalassia testudinum is the dominant seagrass species, in some cases mixed with Syringodium filiforme. The results from the 2009 to 2015 monitoring period are presented here, and contrasted with data before 2009. Total (above and below ground tissue) mean biomass of T. testudinum was higher (1 255.4 ± 146.0 gm-2) than biomass before 2009, with an increasing tendency. However, productivity (1.5±0.59 gm-2d-1) and turnover rate (4.3 ± 1.22 %d-1) were lower than previous monitoring periods. In this period, mean leaf area diminished considerably (4.9 ± 2.30 m2), but leaf area index (LAI) increased (1.9 ± 0.80 m2leafm-2) in comparison to prior monitoring. Productivity, density, turnover rate, LAI and biomass showed intra-annual variations; while mean biomass of T. testudinum did not vary significantly among years. No correlations were found between water salinity, temperature and clarity with seagrass measurements. However, most seagrass parameters were strongly correlated with precipitation. These results highlight the effect of external environmental agents acting on the ecosystem. CNP presents a long-term stable seagrass meadow. However, there are indirect signals, such as high biomass and above-ground biomass proportion, along with low productivity and LAI, which point to a nutrient increment in Perezoso’s seagrass bed. To continue protecting this seagrass bed, it is necessary to improve monitoring methods, and seagrass beds should be included in national conservation policies and monitoring programs.

scholarly journals In Situ Estimation of Carbon Balance of In Vitro Sweetpotato and Tomato Plantlets Cultured with Varying Initial Sucrose Concentrations in the Medium

2002 ◽  
Vol 127 (6) ◽  
pp. 963-970 ◽  
Author(s):  
Chieri Kubota ◽  
Makiko Ezawa ◽  
Toyoki Kozai ◽  
Sandra B. Wilson
Keyword(s):  
Carbon Balance ◽  
Ipomoea Batatas ◽  
Dry Weight ◽  
Photon Flux ◽  
Sugar Uptake ◽  
Relative Contribution ◽  
Carbon Balances ◽  
Species Specific

The effects of initial sucrose (suc) concentrations in the medium (S0) on the carbon balance and growth of sweetpotato [Ipomoea batatas (L.) Lam. `Beniazuma'] and tomato (Lycopersicon esculentum Mill. `HanaQueen') plantlets were studied under controlled environmental conditions. Plantlets were cultured with 0, 7.5, 15, or 30 g·L-1 of S0 under high photosynthetic photon flux (160 to 200 μmol·m-2·s-1) and CO2 enriched (1400 to 2050 μmol·mol-1) conditions. Net photosynthetic rate per leaf area (Pl) decreased and dry weight per plantlet (Wd) increased with increasing S0, but did not differ significantly between S0 of 7.5 to 30 g·L-1 for sweetpotato or 15 to 30 g·L-1 for tomato. Carbon influxes and effluxes of the plantlets by metabolism of medium suc and/or photosynthesis, and respiration were estimated based on measurements of in situ and steady state CO2 exchange rates and sugar uptake during culture. At S0 from 7.5 to 30 g·L-1, photosynthesis was responsible for 82% to 92% and 60% to 67% of carbohydrate assimilation for sweetpotato and tomato, respectively. Estimated carbon balances of plantlets based on the estimated and actual increases of moles of carbon in plant tissue demonstrated that in situ estimation of carbon balance was reasonably accurate for sweetpotato at S0 of 0 to 15 g·L-1 and for tomato at S0 of 0 g·L-1 and that the actual contribution of photosynthesis for tomato at high S0 might be lower than the values estimated in the present experiment. Results showed that initial suc concentration affected the relative contribution of photosynthesis on their carbon balances and that the responses were species specific. The failure of validation at S0 in a range specific to each species suggested the need for further study on carbon metabolism of in vitro plantlets cultured with sugar in the medium.

The Organic carbon content of gravel bed herring spawning grounds and the impact of herring spawn deposition

1993 ◽  
Vol 73 (4) ◽  
pp. 863-870 ◽  
Author(s):  
Ian R. Napier
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Dry Weight ◽  
Published Data ◽  
Organic Carbon Content ◽  
Spawning Grounds ◽  
The Past ◽  
Benthic Food ◽  
The Impact

The dry weight and organic carbon content of eggs and components of Clyde spring herring eggs were measured at intervals during their development. Comparison with previously published data suggests that an increase has occurred in the weight of these eggs over the past thirty years. It is clear that only a small proportion of the material deposited in the form of herring spawn actually remains attached to the substratum when the larvae hatch and so is available for potential integration into the benthic food web. This was confirmed by the determination at intervals over two years of the organic carbon content of the gravel sediments on spawning grounds of the Clyde spring herring. Although the deposition of herring spawn resulted in an immediate marked increase in the carbon content of the spawning ground sediments, carbon levels quickly returned to pre-spawning levels and there was no evidence of any permanent or long lasting increase. This held true when the spawn died and decayed in situ and even when it was mixed into the sediment by wave action. The rapid decrease in carbon levels is attributed to the strong water movements which frequently occur over the spawning grounds.

Food-Limited Growth of Mytilus edulis L. in Relation to the Benthic Boundary Layer

1985 ◽  
Vol 42 (6) ◽  
pp. 1166-1170 ◽  
Author(s):  
Marcel Fréchette ◽  
Edwin Bourget
Keyword(s):  
Mytilus Edulis ◽  
Shell Growth ◽  
Dry Weight ◽  
Benthic Boundary Layer ◽  
Water Interface ◽  
In Situ Growth ◽  
Limited Growth ◽  
Mussel Bed ◽  
Organic Particles

The hypothesis that depletion of organic particles near the sediment limits the growth of benthic suspension feeders was tested. In situ growth of Mytilus edulis L. was significantly depressed at the sediment–water interface, as compared with growth 1.0 m above the mussel bed, in studies at two shore levels. Flesh dry weight was sensitive to treatment effects, but not shell growth. We conclude that mussels from the bed were food limited.

Ecology of periphyton in a meltwater stream ecosystem in the maritime Antarctic

2003 ◽  
Vol 15 (2) ◽  
pp. 189-201 ◽  
Author(s):  
JOSEF ELSTER ◽  
ONDREJ KOMAREK
Keyword(s):  
Linear Models ◽  
Environmental Parameters ◽  
Dry Weight ◽  
Physico Chemical ◽  
Cell Mortality ◽  
Periphyton Biomass ◽  
Negative Relationships ◽  
Microscope Slides ◽  
Petrified Forest

The ecology of two meltwater streams on King George Island, Ornithologists Creek (with penguin rookeries close to its lower reaches) and Petrified Forest Creek (a highly oligotrophic system), was studied during the 1996–97 summer season. To estimate seasonal productivity of the periphyton and to establish which environmental parameters influenced periphyton growth most strongly, two types of artificial substrata (fibreglass nets – ash-free dry weight (AFDW), and microscope slides – Chlorophyll a (Chl a)) were tested in situ. Thus relative periphyton productivity (RPP) reflects algal colonization and growth as well as losses due to cell mortality and abrasive action of moving sediments. The Petrified Forest Creek was more productive (AFDW = 108.63 μg cm−2 d−1, Chl a = 0.35 μg g cm−2 d−1) than the Ornithologists Creek (AFDW = 69.90 μg cm−2 d−-1, Chl a = 0.26 μg cm−2 d−1). RPP differed both along the streams, and during the season. Significant positive or negative relationships (generalized linear models) were found between RPP and streamwater ‘physico-chemical parameters’ and ‘geomorphological-geographical characteristics’ of the streams' catchments. In addition, in the lower reaches of both streams almost no active colonization or growth was recorded. In the Petrified Forest Creek, the periphyton biomass was so high that mainly passive organic matter deposition occurred. By contrast, in the lower reach of Ornithologists Creek, periphyton colonization and growth was around zero, being negatively influenced by penguin excrement. Ornithologists Creek was richer in nutrients (DIN, DRP), which also fluctuated more widely along its length and throughout the season, than in the Petrified Forest Creek. Parameters associated with the inorganic carbon cycle of the streamwater reflect higher RPP in Petrified Forest Creek. Moreover, RPP was higher in stream reaches with higher amounts of gravel boulders on the bottom.

scholarly journals Actinobacterial Nitrate Reducers and Proteobacterial Denitrifiers Are Abundant in N2O-Metabolizing Palsa Peat

2012 ◽  
Vol 78 (16) ◽  
pp. 5584-5596 ◽  
Author(s):  
Katharina Palmer ◽  
Marcus A. Horn
Keyword(s):  
Peat Soil ◽  
Dry Weight ◽  
Content Type ◽  
Finnish Lapland ◽  
Copy Numbers ◽  
Nitrate Reducers ◽  
Discontinuous Permafrost ◽  
Acid Tolerant ◽  
Frost Heaves

ABSTRACTPalsa peats are characterized by elevated, circular frost heaves (peat soil on top of a permanently frozen ice lens) and are strong to moderate sources or even temporary sinks for the greenhouse gas nitrous oxide (N2O). Palsa peats are predicted to react sensitively to global warming. The acidic palsa peat Skalluvaara (approximate pH 4.4) is located in the discontinuous permafrost zone in northwestern Finnish Lapland.In situN2O fluxes were spatially variable, ranging from 0.01 to −0.02 μmol of N2O m−2h−1. Fertilization with nitrate stimulatedin situN2O emissions and N2O production in anoxic microcosms without apparent delay. N2O was subsequently consumed in microcosms. Maximal reaction velocities (vmax) of nitrate-dependent denitrification approximated 3 and 1 nmol of N2O per h per gram (dry weight [gDW]) in soil from 0 to 20 cm and below 20 cm of depth, respectively.vmaxvalues of nitrite-dependent denitrification were 2- to 5-fold higher than thevmaxnitrate-dependent denitrification, andvmaxof N2O consumption was 1- to 6-fold higher than that of nitrite-dependent denitrification, highlighting a high N2O consumption potential. Up to 12 species-level operational taxonomic units (OTUs) ofnarG,nirKandnirS, andnosZwere retrieved. Detected OTUs suggested the presence of diverse uncultured soil denitrifiers and dissimilatory nitrate reducers, hitherto undetected species, as well asActino-,Alpha-, andBetaproteobacteria. Copy numbers ofnirSalways outnumbered those ofnirKby 2 orders of magnitude. Copy numbers ofnirStended to be higher, while copy numbers ofnarGandnosZtended to be lower in 0- to 20-cm soil than in soil below 20 cm. The collective data suggest that (i) the source and sink functions of palsa peat soils for N2O are associated with denitrification, (ii) actinobacterial nitrate reducers andnirS-type andnosZ-harboring proteobacterial denitrifiers are important players, and (iii) acidic soils like palsa peats represent reservoirs of diverse acid-tolerant denitrifiers associated with N2O fluxes.

Comparison of polyphenols and related enzymes in the capsule and nodal tumor of Nicotiana plants

1974 ◽  
Vol 52 (6) ◽  
pp. 1379-1385 ◽  
Author(s):  
S. J. Sheen ◽  
R. A. Andersen
Keyword(s):  
Cell Proliferation ◽  
Phenolic Compounds ◽  
Nicotiana Tabacum ◽  
Chlorogenic Acid ◽  
Dry Weight ◽  
In Situ Synthesis ◽  
Floral Tissue ◽  
Similar Composition ◽  
Tumor Tissues

Extracts of capsules of Nicotiana tabacum cv. Burley 21 and nodal tumors and capsules of a genetically tumor-prone amphiploid N. suaveolens × N. langsdorffii had a similar composition of phenolic compounds. Dihydroxyphenols, predominantly chlorogenic acid, accumulated to 4% and 13% of the dry weight in the young and old tumors, respectively. In situ synthesis of chlorogenic acid in tumor tissues was demonstrated by incorporation of L-phenylalanine-U-14C. Quantities of polyphenols also increased as floral tissue developed from fertilized flower to capsule. The immature capsule and tumor tissues contained more polyphenoloxidase but less peroxidase than the leaf. Peroxidase zymograms, soluble proteins, and alkaloids in tumor extracts resembled those in capsule extracts. It is suggested that these biochemical similarities may reflect a common mode for the regulation of cell proliferation in tobacco capsules and nodal tumors.

In situ dissolved organic carbon (DOC) release by submerged macrophyte–epiphyte communities in southern Quebec lakes

2009 ◽  
Vol 66 (9) ◽  
pp. 1522-1531 ◽  
Author(s):  
M. Demarty ◽  
Y. T. Prairie
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Myriophyllum Spicatum ◽  
Dry Weight ◽  
Release Rates ◽  
Doc Production ◽  
Epiphyte Communities ◽  
Benthic Chambers ◽  
Freshwater Macrophyte

We studied the in situ release of dissolved organic carbon (DOC) by growing a submerged freshwater macrophyte–epiphyte complex. Incubations with benthic chambers in five southeastern Quebec lakes show a net DOC production for different communities of Myriophyllum spicatum and Potamogeton spp. Daytime DOC release rates range from undetectable to 9.7 mg C·m–2·h–1. Although DOC release was restricted to daylight hours and thus suggestive of a photosynthesis-related process, we found no strong link between DOC release rates and concurrent illumination or temperature. We found no difference in DOC release rates between the three main colonizing species of the studied region. The overall mean DOC release rate was 4.57 mg C·m–2·h–1 (standard deviation (SD), ±0.65) or 56 µg C·g dry weight–1·h–1 (SD, ±8), which we suggest can be used for extrapolations at the lake scale.

CO2 assimilation by Dryas integrifolia on Devon Island, Northwest Territories

1973 ◽  
Vol 51 (3) ◽  
pp. 581-588 ◽  
Author(s):  
James M. Mayo ◽  
Don G. Despain ◽  
Eduard M. van Zinderen Bakker Jr.
Keyword(s):  
Northwest Territories ◽  
Environmental Conditions ◽  
Dry Weight ◽  
Co2 Assimilation ◽  
Leaf Temperature ◽  
Maximum Amount ◽  
Assimilation Rate ◽  
Devon Island ◽  
Net Assimilation

In situ measurements of CO2 assimilation by Dryas integrifolia at different stages of development and under different environmental conditions were made on Devon Island, Northwest Territories. Dryas can fix CO2 in excess of respiration over a 24-h period under conditions of clear nights and cloudy days. The maximum net assimilation rate measured was 4.2 mg g−1 dry weight h−1. The maximum amount of CO2 fixed in 24 h was 61.54 mg g−1 dry weight. Maximum net assimilation occurred at 8 to 10 °C leaf temperatures. Positive net assimilation occurred at 1 °C leaf temperature. Light compensation was shown to be less than 0.04 langley min−1. Leaf temperatures were always greater than ambient. The maximum leaf temperature measured was 39 °C. Net assimilation rates appear to decrease as the season progresses.

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