Gross Production Research Articles

Agricultural sector of Akmola region of the Republic of Kazakhstan: methodological approach to assessment and analysis

The goal is to substantiate the current state of agro-industrial complex of the Akmola region, identify the main trends, and determine promising directions for its development. Methods - economic-statistical, analytical. Results show the share of gross regional product (GRP) in the gross domestic product of the republic, the dynamics of gross production (GP) of agriculture in the region, the gross harvest and yield of main agricultural crops, the number of livestock and poultry in all categories of farms, including cattle, sheep and goats, pigs, horses and poultry, volumes of meat and milk processing. A comprehensive study made it possible to identify the problems hindering the development of agro-industrial production in the region, these are, first of all, the small-scale production of economic entities, the majority of farmers and personal subsidiary farms in the total volume of gross agricultural output, the low level of processing of raw materials - their low quality, the insufficient level of utilization of processing facilities enterprises. Conclusions – measures have been proposed to modernize the region’s agro-industrial complex, aimed at the widespread dissemination of agricultural cooperation; development of meat and dairy subcomplexes, processing industry, provision of the population with food products of own production, improvement of state and market regulation of agricultural sectors. The agro-industrial complex also plays a significant social role, solving issues of food supply for the entire country and a certain In addition, it is a guarantor of employment and the main source of income for residents. The effectiveness of its activities contributes to an increase in the number of jobs, an increase in cultivated areas, an increase in the financial stability of manufacturing enterprises, an increase in the volume of product exports and the creation of an export-oriented commodity distribution infrastructure.

Controlling mechanisms and cross linkages of ecosystem metabolism and atmospheric CO2 flux in the northern South China Sea

This study aims to understand the controlling mechanisms of ecosystem metabolic states and air-sea CO2 fluxes and their cross linkages in the northern South China Sea (NSCS). The integrated gross production (IGP), integrated dark community respiration (IDCR), and integrated bacterial respiration (IBR) were all higher in summer than in winter ranging from 851, 435, and 243 to 5032, 10707, and 7547 mg C m−2 d−1, respectively. The discrete estimates of gross production (GP) and dark community respiration (DCR) were modulated by temperature, salinity and nutrient availability through different mechanisms in summer and winter and in shallow (Zhujiang River plumes and shelves) and deep (slope and basin) sampling stations. GP was correlated with DCR (r = 0.74, p < 0.0001), which in turn was largely attributed (65%) to bacterial respiration in the NSCS. Most spatial and summer-winter variability in the IGP/IDCR ratios was less than 1 (heterotrophic), except for in two ratios in winter in the Zhujiang River plume. However, these ratios were higher in winter than in summer because of the vertical pumping of nutrient in winter. Given the higher level of seawater pCO2 in summer than in winter, the NSCS appears to act as a balance to minor source of atmospheric CO2 in summer but a sink in winter. The air−sea fluxes of CO2 and ecosystem metabolic states share a close link in summer but separate in winter. Internal and external sources of dissolved organic carbon may play a key role in causing the heterotrophic conditions and atmospheric CO2 sink in winter.

Regulation and linkages of metabolic states and atmospheric CO2 fluxes in a tropical coastal sea off southwestern Taiwan

The present study aims to understand the mechanisms controlling ecosystem metabolic states and atmospheric CO2 fluxes and explore their linkages through monthly investigations along the tropical Kaoping Submarine Canyon (KPSC) in southwestern Taiwan. The magnitudes of integrated gross production (IGP) and integrated dark community respiration (IDCR) were higher in summer than in winter, likely supported by greater inputs of freshwater in summer with high loads of nutrients and organic carbon. Strong positive correlations were observed between gross production (GP) (or dark community respiration (DCR)) and temperature, photosynthetically active radiation and nutrients, but negative correlations were observed between GP (or DCR) and salinity in discrete water samples; these results reveal the significant impacts of freshwater inputs on GP and DCR. GP was determined largely by DCR, and DCR was attributed largely (78%) to bacterial respiration in the KPSC. Approximately 60% of measurements were autotrophic conditions (IGP/IDCR >1) in most wet seasons except for certain offshore stations, which were apparently driven by higher temperature and nutrient availability, whereas 40% of measurements revealed heterotrophic conditions (IGP/IDCR <1) in most offshore stations. The air-sea fluxes of CO2 revealed that about 64% of all measurements were sinks of atmospheric CO2, but those sinks did not completely coincide temporally with autotrophic conditions. Biological controls [GP correlated significantly with nutrients and chlorophyll a and was primarily determined by DCR] and temperature effects may overwhelmingly dictate metabolic states and air-sea fluxes of atmospheric CO2, respectively, though the combined effects were evident in this coastal ecosystem. The study may shed light on implications of recent increases in nutrient inputs for shifting the coastal ecosystem from heterotrophic to autotrophic conditions, and the global warming per se may increase the chance for tropical coastal ecosystems acting as a source of atmospheric CO2.

Variations in triple isotope composition of dissolved oxygen and primary production in a subtropical reservoir

Abstract. Lakes and reservoirs play an important role in the carbon cycle, and therefore monitoring their metabolic rates is essential. The triple oxygen-isotope anomaly of dissolved O2 [17Δ = ln(1+δ17O) − 0.518 × ln(1 + δ18O)] offers a new, in situ, perspective on primary production, yet little is known about 17Δ from freshwater systems. We investigated the 17Δ together with the oxygen : argon ratio [Δ(O2 ∕ Ar)] in the subtropical Feitsui Reservoir in Taiwan from June 2014 to July 2015. Here, we present the seasonal variations in 17Δ, GP (gross production), NP (net production) and the NP ∕ GP (net to gross ratio) in association with environmental parameters. The 17Δ varied with depth and season, with values ranging between 26 and 205 per meg. The GP rates were observed to be higher (702 ± 107 mg C m−2 d−1) in winter than those (303 ± 66 mg C m−2 d−1) recorded during the summer. The overall averaged GP was 220 g C m−2 yr−1 and NP was −3 g C m−2 yr−1, implying the reservoir was net heterotrophic on an annual basis. This is due to negative NP rates from October to February (−198 ± 78 mg C m−2 d−1). Comparisons between GP rates obtained from the isotope mass balance approach and 14C bottle incubation method (14C–GP) showed consistent values on the same order of magnitude with a GP ∕ 14C–GP ratio of 1.2 ± 1.1. Finally we noted that, although typhoon occurrences were scarce, higher than average 17Δ values and GP rates were recorded after typhoon events.

Systematically variable planktonic carbon metabolism along a land-to-lake gradient in a Great Lakes coastal zone.

During the summers of 2002–2013, we measured rates of carbon metabolism in surface waters of six sites across a land-to-lake gradient from the upstream end of drowned river-mouth Muskegon Lake (ML) (freshwater estuary) to 19 km offshore in Lake Michigan (LM) (a Great Lake). Despite considerable inter-year variability, the average rates of gross production (GP), respiration (R) and net production (NP) across ML (604 ± 58, 222 ± 22 and 381 ± 52 µg C L−1 day−1, respectively) decreased steeply in the furthest offshore LM site (22 ± 3, 55 ± 17 and −33 ± 15 µg C L−1day−1, respectively). Along this land-to-lake gradient, GP decreased by 96 ± 1%, whereas R only decreased by 75 ± 9%, variably influencing the carbon balance along this coastal zone. All ML sites were consistently net autotrophic (mean GP:R = 2.7), while the furthest offshore LM site was net heterotrophic (mean GP:R = 0.4). Our study suggests that pelagic waters of this Great Lakes coastal estuary are net carbon sinks that transition into net carbon sources offshore. Reactive and dynamic estuarine coastal zones everywhere may contribute similarly to regional and global carbon cycles.

Planktonic community metabolism in two stratified Mediterranean reservoirs with different trophic status

Community metabolism plays a crucial role in the carbon dynamics of continental aquatic ecosystems. In the present work, two Mediterranean reservoirs (Southern Spain) with different trophic status were monitored during the stratified phase over two consecutive years (2009 and 2010) to evaluate community metabolic dynamics and potential controlling factors. Dark and light incubations were performed in order to estimate the daily rates of gross production (GP), community respiration (CR) and net community production (NCP). Temperature, irradiance, chlorophyll, phosphorus and carbon concentration were also measured at different depths within the mixed layer. On average, results showed heterotrophic behavior (GP &amp;lt; CR) in both reservoirs, which was particularly evident in the more eutrophic reservoir. Interannual climate variability was high due to the exceptionally rainy winter of 2010. This resulted in a significant decrease in the magnitude of the heterotrophic balance in both reservoirs. The change in NCP was especially evident in the most eutrophic reservoir where high water renewal rates lead to a lower CR. In general, NCP was found to be directly related to the ratio between the euphotic layer depth and the mixed layer depth, and inversely related to the particulate phosphorus concentration. Autotrophic behavior was only found in conditions of high irradiance (mixed layer shallower than euphotic layer), relatively low concentrations of dissolved organic carbon (&amp;lt;6 mg L−1) and particulate phosphorus (&amp;lt;10 μg L−1), and moderate chlorophyll concentration (2–9 μg L−1), albeit these conditions did not always lead to a net autotrophic balance.

Comparison of in vitro and in situ plankton production determinations

Plankton production was measured using 8 techniques at 4 stations in the Celtic Sea, North Atlantic Ocean, in April 2002. Primary production (PP) was derived from 14 C incorporation into particulate carbon after 24 h simulated in situ, PP( 14 CSIS), and 2 h photosynthesis-irradiance incuba- tions, PP( 14 CPUR), and from 2 published satellite algorithms, PP(VGPM) and PP(M91). Gross production (GP) was calculated from O2 evolution, GP(O2), and 18 O enrichment of dissolved O2, GP( 18 O), after 24 h simulated in situ incubations, and from in situ active fluorescence measured by fast repetition rate fluorometry (FRRF). Net community production (NCP) was determined from changes in in situ dissolved oxygen, NCP(ΔO2), and from changes in oxygen during 24 h simulated in situ incubations, NCP(O2). Dark community respiration (DCR) was derived from changes in oxygen during a 24 h dark incubation, DCR(O2), and daily oxygen uptake, DOU( 18 O, O2), was calculated from the difference between GP( 18 O) and NCP(O2). Three stations were dominated by picoautotrophs and the fourth station was dominated by diatoms. While most of the comparisons between techniques fell within previously published ranges, 2 anomalies occurred only at the diatom-dominated station. Rates of PP( 14 CPUR) were oxygen uptake in the dark. The low rates of PP( 14 CPUR) in relation to PP( 14 CSIS) may have resulted from the heterogeneous nature of the bloom and differences in sampling time. However, it is also possible that dissolved organic material (DOM) released by the stressed diatom population restricted the diffusion of 14 C into the cells, thereby causing a greater underestimate of PP by techniques using short incuba- tions. The significantly higher rates of oxygen uptake in the light are difficult to reconcile, and we do not know whether the light enhanced oxygen uptake was directly linked to carbon fixation. How- ever, the release of DOM may also have provided substrate for enhanced respiration in the light. These anomalies were only revealed through the concurrent measurement of plankton production by this wide range of techniques. Further investigation of DOM excretion and light-enhanced respira- tion during diatom blooms is warranted.

Effects of tidal flushing on phytoplankton in a eutrophic tropical lagoon in Taiwan

The effects of tidal flushing on the abundance, productivity, and community structure of phytoplankton in response to eutrophication were examined every 2–3 months for more than 2 years in Tapong Bay, a tropical lagoon with only 1 tidal inlet connecting it to the sea in southern Taiwan. Water flushing time ranged from 4–12 d (8–25% d −1) in the outer region subject to fast flushing to 8–24 d (4–12% d −1) in the inner region subject to poor flushing. Chlorophyll a, cell number, and gross production (GP) rate of phytoplankton were significantly greater in the inner region than in the outer region. However, while GP rate was normalized by chlorophyll a (P B) and was expressed as photosynthetic intensity, no significant differences were detected among the study sites. These parameters exhibited a unimodal seasonal pattern across all study sites, with greater values in summer and lower values in winter. No significant differences in species richness or Shannon–Wiener diversity were detected among the study sites. Nevertheless, diversity indices were significantly higher in winter and lower in summer. Classification of phytoplankton communities showed that the grouping patterns were primarily determined by sampling time. Ordination by non-metric multidimensional scaling (MDS) revealed a clear temporal continuum of changes in species composition across all study sites, suggesting that the communities were primarily structured by time, but that it was little affected by study site. Analyses of similarities (ANOSIM) showed that phytoplankton communities sampled in winter could be separated from those in summer, but others were barely separable at all. In summer, the most frequently observed species were the diatom Skeletonema costatum and the cyanobacterium Oscillatoria sp., and these shifted to the diatoms S. costatum and Cylindrotheca closterium in winter. Our results suggest that tidal flushing is an important factor for regulating responses of phytoplankton abundance and productivity to eutrophication in tropical lagoons, but the community structure was little affected due to horizontal mixing by the tidal circulation.

Plankton respiration in the Eastern Atlantic Ocean

Concurrent measurements of dark community respiration (DCR), gross production (GP), size fractionated primary production ( 14C PP), nitrogen uptake, nutrients, chlorophyll a concentration, and heterotrophic and autotrophic bacterial abundance were collected from the upper 200 m of a latitudinal (32°S–48°N) transect in the Eastern Atlantic Ocean during May/June 1998. The mean mixed layer respiration rate was 2.5±2.1 mmol O 2 m −3 d −1 ( n=119) for the whole transect, 2.2±1.1 mmol O 2 m −3 d −1 ( n=32) in areas where chlorophyll a was <0.5 mg m −3 and 1.5±0.7 mmol O 2 m −3 d −1 ( n=10) where chlorophyll a was <0.2 mg m −3. These values lie within the range of published data collected in comparable waters, they co-vary with indicators of heterotrophic and autotrophic biomass (heterotrophic bacterial abundance, chlorophyll a concentration, beam attenuation and particulate organic carbon concentration) and they can be reconciled with accepted estimates of total respiratory activity. The mean and median respiratory quotient (RQ), calculated as the ratio of dissolved inorganic carbon production to dissolved oxygen consumption, was 0.8 ( n=11). At the time of the study, plankton community respiration exceeded GP in the picoautotroph dominated oligotrophic regions (Eastern Tropical Atlantic [15.5°S–14.2°N] and North Atlantic Subtropical Gyre [21.5–42.5°N]), which amounted to 50% of the stations sampled along the 12,100 km transect. These regions also exhibited high heterotrophic: autotrophic biomass ratios, higher turnover rates of phytoplankton than of bacteria and low f ratios. However, the carbon supply mechanisms required to sustain the rates of respiration higher than GP could not be fully quantified. Future research should aim to determine the temporal balance of respiration and GP together with substrate supply mechanisms in these ocean regions.

Plankton community respiration during a coccolithophore bloom

Abstract Plankton dark community respiration (DCR), gross production (GP), bacterial production, protozoan herbivory, and phytoplankton, microzooplankton and heterotrophic bacterial abundance were measured during a bloom of the coccolithophore Emiliania huxleyi. The study, which was conducted in the northern North Sea during June 1999, included a spatial survey and a 6-day Lagrangian time series informed by a sulphur hexafluoride (SF6) tracer-release experiment. E. huxleyi abundance in surface waters ranged from 380 to 3000 cells ml−1, while DCR varied between 2 and 4 mmol O2 m−3 d−1 and GP between 2 and 5 mmol O2 m−3 d−1. Euphotic zone integrated DCR and GP were in approximate balance, with a mean (±SD) P:R ratio of 0.9±0.4 (n=9). However, highest GP occurred at the surface alongside maxima of E. huxleyi, whereas highest rates of DCR occurred at depths of 25–30 m associated with maxima in chlorophyll a and bacterial biomass. DCR was positively correlated with bacterial biomass, microzooplankton biomass, attenuance, particulate organic carbon, and chlorophyll a concentration; and negatively correlated with apparent oxygen utilisation. DCR was not correlated with in situ temperature, dissolved organic carbon concentration or E. huxleyi abundance. A∼100 h incubation of 0.8 μm filtered seawater enabled the estimation of a bacterial respiratory quotient (RQ) and growth efficiency (BGE) from the slopes of the linear regressions of the decrease in dissolved oxygen and increase in dissolved inorganic carbon (DIC) and bacterial carbon with time. During this experiment the bacterial RQ was 0.69 and the growth efficiency was 18%. This measured BGE was used in comparison with literature values to apportion DCR to that associated with bacterial (13–71%), microzooplankton (10–50%), and algal (11–28%) activity. This accounting exercise compared well with measured DCR (to within ±50%), the exact calculation being highly dependent on the BGE used.

Significance of pelagic and benthic primary production in two shallow coastal lagoons of different degrees of eutrophication in the southern Baltic Sea

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 20:273-284 (1999) - doi:10.3354/ame020273 Significance of pelagic and benthic primary production in two shallow coastal lagoons of different degrees of eutrophication in the southern Baltic Sea Jürgen Meyercordt*, Sabine Gerbersdorf, Lutz-Arend Meyer-Reil Institut für Ökologie, Ernst-Moritz-Arndt-Universität Greifswald, 18565 Kloster/Hiddensee, Germany *E-mail: meyercor@rz.uni-greifswald.de ABSTRACT: Primary production by pelagic and benthic microalgae was measured in 2 shallow coastal lagoons in the southern Baltic Sea by in situ and laboratory incubations to quantify the significance of these 2 major groups of primary producers in absolute and relative terms. Pelagic primary production rates per volume at saturating light conditions were 7 to 12 times higher at the polytrophic location Kirr-Bucht (Darss-Zingst Bodden) than at the meso-/eutrophic location Rassower Strom (Nordrügensche Bodden). Chlorophyll a specific primary production rates, however, were in the same range at both locations, except for 1 situation in spring which is explicitly discussed. The pelagic chlorophyll a specific maximum light utilization coefficient (a*) tended towards higher values in Kirr-Bucht samples, which can be interpreted as an adaptation to a lower supply of irradiance. Pelagic and benthic primary production varied seasonally, with highest rates occurring in June/July. A calculation of short-term variability due to cloud-modulated availability of irradiance revealed reductions of pelagic and benthic gross production (GP) rates on overcast days, compared to bright days, in the range of 26 to 69% and 62 to 82%, respectively. Net community production (NP) rates were more severely reduced than GP rates on overcast days. Benthic NP was generally reduced to below zero on overcast days, whereas it was mostly positive on bright days at both locations. To evaluate the significance of the different optical properties of both types of water (diffuse vertical attenuation coefficient, k = 3.3 to 3.7 and 0.5 to 0.7 m-1 at Kirr-Bucht and Rassower Strom, respectively) for primary production, the benthic and pelagic contributions at both sites were calculated regarding a water depth of 2 m, which is about the mean depth of the Bodden systems. This standardization revealed obvious differences in basic conditions for primary production which remained undetected when the comparison of the 2 sites was based on the water depths in which the in situ incubations had been carried out (0.6 and 3.4 m at Kirr-Bucht and Rassower Strom, respectively). In meso-/eutrophic Rassower Strom at a depth of 2 m, benthic GP would contribute about 30 to 45% to the total GP of microalgae, depending on weather conditions and seasons. At the same depth in polytrophic Kirr-Bucht, the microalgae on the sediment surface would account for only 0.3% or less of total GP. This demonstrates that optical properties of the water, which are closely related to the trophic state of the system, exert strong control on varying proportions of productivity, attributable to planktonic versus benthic microalgal communities. It can be concluded from the modeled data that the difference between both locations will be most prominent during periods of low supply of radiant energy, like on overcast days. KEY WORDS: Primary production · Phytoplankton · Microphytobenthos · Irradiance · Eutrophication · Estuary · Baltic Sea Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 20, No. 3. Publication date: December 30, 1999 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 1999 Inter-Research.

Measurement of oxygen production and demand in lake waters

Abstract By use of a modern BOD bottle probe, a digital read‐out meter, and quadruplicate sampling, oxygen concentrations were routinely measured with a precision of ± 0.02 g DO m−3. This level of accuracy permitted measurement of Water Oxygen Demand (WOD), Net Production (NP), and Gross Production (GP) at all depths in the water column of lakes. Sediment Oxygen Demand (SOD) was also measured and found to be small when compared to the total water column oxygen demand in unstratified water but was a significant part of the hypolimnetic oxygen uptake. Measurements of GP were found to correlate closely with primary production values determined independently by means of the 14C technique. Significant GP was also found in the hypolimnion of a mesotrophic lake, indicating that WOD does not always provide a measure of hypolimnetic oxygen uptake; net production does so in this situation. Further, WOD was found to decrease by about 20% per day in incubated samples, revealing that WOD incubations should never excee...

Impacts of Public Research Expenditures on Agricultural Value-Added in the U.S. and the Northeast

This paper illustrates differences in estimated returns to public agricultural research investments for the U.S. and the Northeast when value-added (VA) as opposed to gross production (GP) functions are estimated. Commodity groups considered are dairy, poultry, other livestock, and cash grains. Sizable differences are evident in returns estimated with VA as opposed to GP functions, with the VA estimates generally being larger. Cash grains research yields the largest returns at the margin. Dairy research is more productive in the Northeast than the rest of the country.

Relationships Between Metabolic Parameters and Stream Order in Oregon

The light regime, standing stock of chlorophyll, and five metabolic parameters were measured seasonally at four Oregon stream sites; Devils Club Creek (1st order), Mack Creek (3rd order), Lookout Creek (5th order), and the McKenzie River (7th order). Periphyton from pools and riffles, aquatic moss (Fontinalis), fine particulate organic matter (FPOM: 0.5 μm–1 cm), and coarse particulate organic matter (CPOM: &gt; 1 cm) were examined separately for gross production (GP), net community production (NCP), diel respiration (R24), net daily metabolism (NDM), and the production to respiration (P:R) ratio. Total autotrophic production was found to increase in a downstream direction where more light is available; however, the efficiency of light utilization is greatest in heavily shaded Mack Creek. Detrital metabolism, per unit weight, is similar in all streams for each metabolic parameter. The standing stock of detritus though, is highest in headwater streams, decreasing as streams become larger. Therefore, the relative contribution of the detritus community to total metabolism decreases downstream. Mosses occur in significant quantities only in the McKenzie River and have an areal community respiration rate about twice that of periphyton; other metabolic parameters are nearly equal in this case. On an areal basis periphyton metabolism is much greater than detrital metabolism and, as a consequence, total stream metabolism and the P:R ratio increase downstream.Gross production rates measured for these sites are some of the lowest recorded (0.1–1.0 g O2∙m−2∙d−1). These rates are compared to those from other streams in the northwestern United States and western Canada, and the importance of photosynthesis to stream systems is demonstrated. The decomposition rate of the detrital standing stock is estimated to be 0.0029–0.0057%∙m−2∙d−1 and the turnover time is calculated to be 48–93 yr for particles &lt; 10 cm in diameter.Key words: streams, rivers, metabolism, primary production, detritus, photosynthesis, chlorophyll, respiration, light, Oregon