Primary Productivity in the Sea: Reef Corals in Situ

1980 ◽  
pp. 403-410 ◽  
Author(s):  
James W. Porter
Keyword(s):  
Primary Productivity ◽  
Reef Corals

scholarly journals Simulating Spatiotemporal Dynamics of Sichuan Grassland Net Primary Productivity Using the CASA Model and In Situ Observations

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Chuanjiang Tang ◽  
Xinyu Fu ◽  
Dong Jiang ◽  
Jingying Fu ◽  
Xinyue Zhang ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Alpine Meadow ◽  
Growth Period ◽  
Temporal Variations ◽  
Light Use Efficiency ◽  
Important Indicator ◽  
Casa Model ◽  
Use Efficiency

Net primary productivity (NPP) is an important indicator for grassland resource management and sustainable development. In this paper, the NPP of Sichuan grasslands was estimated by the Carnegie-Ames-Stanford Approach (CASA) model. The results were validated with in situ data. The overall precision reached 70%; alpine meadow had the highest precision at greater than 75%, among the three types of grasslands validated. The spatial and temporal variations of Sichuan grasslands were analyzed. The absorbed photosynthetic active radiation (APAR), light use efficiency (ε), and NPP of Sichuan grasslands peaked in August, which was a vigorous growth period during 2011. High values of APAR existed in the southwest regions in altitudes from 2000 m to 4000 m. Light use efficiency (ε) varied in the different types of grasslands. The Sichuan grassland NPP was mainly distributed in the region of 3000–5000 m altitude. The NPP of alpine meadow accounted for 50% of the total NPP of Sichuan grasslands.

scholarly journals Estimation of the Particulate Organic Carbon to Chlorophyll-a Ratio Using MODIS-Aqua in the East/Japan Sea, South Korea

2020 ◽  
Vol 12 (5) ◽  
pp. 840 ◽  
Author(s):  
Dabin Lee ◽  
SeungHyun Son ◽  
HuiTae Joo ◽  
Kwanwoo Kim ◽  
Myung Joon Kim ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Chlorophyll A ◽  
Primary Productivity ◽  
Seasonal Variability ◽  
Japan Sea ◽  
Global Ocean ◽  
Phytoplankton Communities

In recent years, the change of marine environment due to climate change and declining primary productivity have been big concerns in the East/Japan Sea, Korea. However, the main causes for the recent changes are still not revealed clearly. The particulate organic carbon (POC) to chlorophyll-a (chl-a) ratio (POC:chl-a) could be a useful indicator for ecological and physiological conditions of phytoplankton communities and thus help us to understand the recent reduction of primary productivity in the East/Japan Sea. To derive the POC in the East/Japan Sea from a satellite dataset, the new regional POC algorithm was empirically derived with in-situ measured POC concentrations. A strong positive linear relationship (R2 = 0.6579) was observed between the estimated and in-situ measured POC concentrations. Our new POC algorithm proved a better performance in the East/Japan Sea compared to the previous one for the global ocean. Based on the new algorithm, long-term POC:chl-a ratios were obtained in the entire East/Japan Sea from 2003 to 2018. The POC:chl-a showed a strong seasonal variability in the East/Japan Sea. The spring and fall blooms of phytoplankton mainly driven by the growth of large diatoms seem to be a major factor for the seasonal variability in the POC:chl-a. Our new regional POC algorithm modified for the East/Japan Sea could potentially contribute to long-term monitoring for the climate-associated ecosystem changes in the East/Japan Sea. Although the new regional POC algorithm shows a good correspondence with in-situ observed POC concentrations, the algorithm should be further improved with continuous field surveys.

A Comparison of Liquid Scintillation and Geiger–Müller Estimates of Primary Productivity in an in situ Experiment

1973 ◽  
Vol 30 (5) ◽  
pp. 708-711 ◽  
Author(s):  
F. J. Ward ◽  
Masami Nakanishi
Keyword(s):  
Light Intensity ◽  
Surface Area ◽  
Primary Productivity ◽  
Liquid Scintillation ◽  
Lake Biwa ◽  
In Situ Experiment ◽  
M Estimate ◽  
M Estimates ◽  
Loss Rates

For an in situ experiment conducted in Shiozu Bay, Lake Biwa, Japan, primary productivity estimates from liquid scintillation radioactivity counts of wet algae were generally higher than those from Geiger–Müller radioactivity counts of desiccated algae. Values at 0 m were similar, the G–M estimate at 0.5 m was 10% higher, but from 3 to 13 m the liquid scintillation values ranged from 11 to 33% higher than G–M estimates. The 20-m estimates were low and similar. Differences were caused primarily by 14C losses during desiccation prior to G–M counting. Increasing loss rates between 0.5 and 3.0 m may have been caused by decreasing light intensity. On the basis of surface area, the estimate from liquid scintillation data was 27% greater than that obtained from G–M data.

Simulating Gross Primary Productivity of vegetation under soil water stress using in-situ and reanalysis soil moisture data inputs

2020 ◽  
Author(s):  
Timothy Lam ◽  
Amos P. K. Tai
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Soil Water ◽  
Primary Productivity ◽  
Gross Primary Productivity ◽  
Efficiency Coefficient ◽  
Community Land Model ◽  
Soil Water Stress ◽  
Soil Moisture Data

<p>This study utilises in-situ and reanalysis soil moisture data inputs from various sources to evaluate the effect of soil water stress on Gross Primary Productivity (GPP) of different Plant Functional Types (PFTs) using Terrestrial Ecosystem Model in R (TEMIR), which is under development by Tai Group of Atmosphere-Biosphere Interactions (Tai et al. in prep.). An empirical soil water stress function with reference to Community Land Model (CLM) Version 4.5 is employed to quantify water stress experienced by vegetation which hinders stomatal conductance and thus carboxylation rate. The model results are compared against observations at FLUXNET sites in semi-arid regions across the globe at daily timescale where in-situ GPP data is available and water stress inhibits plant functions to some extent. By dividing the soil into two layers (topsoil and root zone), GPP simulation improves significantly comparing with using single layer bulk soil (Modified Nash-Sutcliffe Model Efficiency Coefficient N increases from -0.686 to -0.586). Such upgrade is particularly substantial for vegetation with shallow roots such as grass PFTs. Despite this improvement, the model is characterised by an overall overestimation of GPP when water stress occurs, and inconsistency of accuracy subject to PFTs and degree of water stress experienced. This study informs responses of various PFTs to soil water stress, capacity of TEMIR in simulating the responses, and possible drawbacks of empirical soil water stress functions, and highlights the importance of topsoil moisture data input for vegetation drought monitoring.</p><p>Keywords: Soil water stress, Terrestrial model representation, Photosynthesis, In-situ data, Reanalysis data, FLUXNET</p>

The English–Wabigoon River System: V. Mercury and Selenium Bioaccumulation as a Function of Aquatic Primary Productivity

1983 ◽  
Vol 40 (12) ◽  
pp. 2251-2259 ◽  
Author(s):  
John W. M. Rudd ◽  
Michael A. Turner
Keyword(s):  
Growth Rate ◽  
Primary Productivity ◽  
Growth Rates ◽  
River System ◽  
Whole Body ◽  
Aquatic Food Chain ◽  
Mercury Bioaccumulation ◽  
Aquatic Food ◽  
Stimulation Of

An experiment was carried out in four 100-m3 in situ enclosures to determine the effect of primary production rate on mercury and selenium concentrations of biota and to test the possibility of ameliorating mercury pollution problems by increasing ecosystem primary productivity. Two enclosures were controls. Primary productivity in a third enclosure was increased fourfold by addition of NaNO3 and NaH2PO4. This stimulation was not sufficient to change pH although the growth rate of fish was enhanced. In this enclosure, mercury concentrations in pearl dace (Semotilus margarita) whole body and muscle samples increased two- and five-fold, respectively, exceeding the dilution of mercury by the enhanced growth rates. In the fourth enclosure, at the highest rate of nutrient addition, primary productivity was increased ninefold, pH was elevated from about 7.9 to 9.2, and the growth rate of fish was stimulated. In this case, the elevation of pH retarded the rate of mercury bioaccumulation in comparison with the enclosure of intermediate productivity. Based on these results, stimulation of primary productivity is not recommended as a mercury ameliorating procedure. Stimulation of primary productivity resulted in a general decrease in the concentration of selenium in the aquatic food chain probably resulting from dilution of selenium by enhanced growth rates of fish and other biota.

Observations on the snow algae of the South Orkney Islands

1967 ◽  
Vol 252 (777) ◽  
pp. 279-287 ◽  
Keyword(s):  
Metabolic Activity ◽  
Primary Productivity ◽  
Algal Species ◽  
The South ◽  
Orkney Islands ◽  
Snow Algae ◽  
South Orkney Islands ◽  
Sudden Appearance ◽  
Direct Counts

One of the most abundant algal species found in snow on the South Orkney Islands is a unicellular chrysophycean not hitherto reported from this region. Investigations both by direct counts and by in situ determinations of metabolic activity by a radiocarbon technique suggest that growth of snow algae is, in general, slow. Their primary productivity is estimated as being of the order of 10 mg carbon fixed m-2 snow surface day-1. The sudden appearance of patches of these algae seems to be due to mechanical accumulation at the surface, as ablation of the snow proceeds, of cells previously distributed sparsely through its thickness. There appear to be no great differences either in species composition or in metabolic activity between green, yellow and red snow. The greater population densities and absence of red resting spores characteristic of green snow are perhaps attributable to greater availability of liquid water.

scholarly journals No impact of tropospheric ozone on the gross primary productivity of a Belgian pine forest

2017 ◽  
Vol 14 (7) ◽  
pp. 1839-1855 ◽  
Author(s):  
Lore T. Verryckt ◽  
Maarten Op de Beeck ◽  
Johan Neirynck ◽  
Bert Gielen ◽  
Marilyn Roland ◽  
...  
Keyword(s):  
Scots Pine ◽  
Primary Productivity ◽  
Crop Yields ◽  
Gross Primary Productivity ◽  
Carbon Uptake ◽  
Tree Seedlings ◽  
Mixing Ratio ◽  
Negative Effects ◽  
Uptake Rates

Abstract. High stomatal ozone (O3) uptake has been shown to negatively affect crop yields and the growth of tree seedlings. However, little is known about the effect of O3 on the carbon uptake by mature forest trees. This study investigated the effect of high O3 events on gross primary productivity (GPP) for a Scots pine stand near Antwerp, Belgium over the period 1998–2013. Stomatal O3 fluxes were modelled using in situ O3 mixing ratio measurements and a multiplicative stomatal model, which was parameterised and validated for this Scots pine stand. Ozone-induced GPP reduction is most likely to occur during or shortly after days with high stomatal O3 uptake. Therefore, a GPP model within an artificial neural network was parameterised for days with low stomatal O3 uptake rates and used to simulate GPP during periods of high stomatal O3 uptake. Possible negative effects of high stomatal O3 uptake on GPP would then result in an overestimation of GPP by the model during or after high stomatal O3 uptake events. The O3 effects on GPP were linked to AOT40 and POD1. Although the critical levels for both indices were exceeded in every single year, no significant negative effects of O3 on GPP were found, and no correlations between GPP residuals and AOT40 and POD1 were found. Overall, we conclude that no O3 effects were detected on the carbon uptake by this Scots pine stand.

A battery operated incubator for in situ primary productivity studies in small lakes and rivers

Hydrobiologia ◽  
1983 ◽  
Vol 101 (3) ◽  
pp. 243-245
Author(s):  
J. E. Furet ◽  
K. Benson-Evans ◽  
J. E. Grey
Keyword(s):  
Primary Productivity ◽  
Small Lakes
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