scholarly journals Peru upwelling plankton respiration: calculations of carbon flux, nutrient retention efficiency and heterotrophic energy production

2014 ◽  
Vol 11 (11) ◽  
pp. 16177-16206 ◽  
Author(s):  
T. T. Packard ◽  
N. Osma ◽  
I. Fernández-Urruzola ◽  
L. A. Codispoti ◽  
J. P. Christensen ◽  
...  
Keyword(s):  
Water Column ◽  
Depth Profile ◽  
Carbon Flux ◽  
Energy Production ◽  
Nutrient Retention ◽  
Euphotic Zone ◽  
Nutrient Regeneration ◽  
Retention Efficiency ◽  
High Productivity ◽  
Water Column Respiration

Abstract. Oceanic depth profiles of plankton respiration are described by a power function, RCO2 = (RCO2)0(z/z0)b similar to the vertical carbon flux profile. Furthermore, because both ocean processes are closely related, conceptually and mathematically, each can be calculated from the other. The exponent (b), always negative, defines the maximum curvature of the respiration depth-profile and controls the carbon flux. When b is large, the C flux (FC) from the epipelagic ocean is low and the nutrient retention efficiency (NRE) is high allowing these waters to maintain high productivity. The opposite occurs when b is small. This means that the attenuation of respiration in ocean water columns is critical in understanding and predicting both vertical FC as well as the capacity of epipelagic ecosystems to retain their nutrients. The NRE is a new metric defined as the ratio of nutrient regeneration in a seawater layer to the nutrients introduced into that layer via FC. A depth-profile of FC is the integral of water column respiration. This relationship facilitates calculating ocean sections of FC from water column respiration. In a FC section across the Peru upwelling system we found a FC maximum extending down to 400 m, 50 km off the Peru coast. Finally, coupling respiratory electron transport system activity to heterotrophic oxidative phosphorylation promoted the calculation of an ocean section of heterotrophic energy production (HEP). It ranged from 250 to 500 J d−1 m−3 in the euphotic zone, to less than 5 J d−1 m−3 below 200 m on this ocean section.

scholarly journals Peruvian upwelling plankton respiration: calculations of carbon flux, nutrient retention efficiency, and heterotrophic energy production

2015 ◽  
Vol 12 (9) ◽  
pp. 2641-2654 ◽  
Author(s):  
T. T. Packard ◽  
N. Osma ◽  
I. Fernández-Urruzola ◽  
L. A. Codispoti ◽  
J. P. Christensen ◽  
...  
Keyword(s):  
Water Column ◽  
Depth Profile ◽  
Carbon Flux ◽  
Energy Production ◽  
Nutrient Retention ◽  
Euphotic Zone ◽  
Nutrient Regeneration ◽  
Retention Efficiency ◽  
High Productivity ◽  
Water Column Respiration

Abstract. Oceanic depth profiles of plankton respiration are described by a power function, RCO2 = (RCO2)0 (z/z0)b, similar to the vertical carbon flux profile. Furthermore, because both ocean processes are closely related, conceptually and mathematically, each can be calculated from the other. The exponent b, always negative, defines the maximum curvature of the respiration–depth profile and controls the carbon flux. When |b| is large, the carbon flux (FC) from the epipelagic ocean is low and the nutrient retention efficiency (NRE) is high, allowing these waters to maintain high productivity. The opposite occurs when |b| is small. This means that the attenuation of respiration in ocean water columns is critical in understanding and predicting both vertical FC as well as the capacity of epipelagic ecosystems to retain their nutrients. The ratio of seawater RCO2 to incoming FC is the NRE, a new metric that represents nutrient regeneration in a seawater layer in reference to the nutrients introduced into that layer via FC. A depth profile of FC is the integral of water column respiration. This relationship facilitates calculating ocean sections of FC from water column respiration. In an FC section and in a NRE section across the Peruvian upwelling system we found an FC maximum and a NRE minimum extending down to 400 m, 50 km off the Peruvian coast over the upper part of the continental slope. Finally, considering the coupling between respiratory electron transport system activity and heterotrophic oxidative phosphorylation promoted the calculation of an ocean section of heterotrophic energy production (HEP). It ranged from 250 to 500 J d−1 m−3 in the euphotic zone to less than 5 J d−1 m−3 below 200 m on this ocean section.

scholarly journals Nutrient Limitation and Uptake Rates in Streams and Rivers of the Greater Yellowstone Ecosystem

2013 ◽  
Vol 36 ◽  
pp. 153-159
Author(s):  
Jennifer Tank ◽  
Alexander Reisinger
Keyword(s):  
Water Quality ◽  
Nutrient Limitation ◽  
Water Column ◽  
Nutrient Dynamics ◽  
Nutrient Retention ◽  
Light Limitation ◽  
Small Stream ◽  
Streams And Rivers ◽  
Greater Yellowstone ◽  
Uptake Studies

Nutrient pollution of aquatic ecosystems is a growing concern as the influence of human activities continues to increase on the landscape. Headwater streams have long been shown to process nutrients via the biofilm community growing on the bottom of streams. The growth and activity of these biofilms is often limited by the availability of nitrogen (N), phosphorus (P), or co-limited by both N and P. Although small stream nutrient dynamics are relatively well understood, comparatively little is known about larger, non-wadeable rivers. Biofilms on the river bottom are likely still nutrient limited, but there becomes an increased potential for light limitation as rivers increase in depth. In addition to biofilms on the bottom of rivers, free-living microbial communities suspended in the water column also occur in rivers and process nutrients - a component of nutrient processing largely ignored in streams. In summer 2013 we worked in streams and rivers of the Greater Yellowstone Area (GYA) to establish the nutrient limitation status of minimally-impacted rivers, as well as the role of the water column in processing nutrients as streams increase in size. For both the nutrient limitation and water column uptake studies, we are using the GYA sites in addition to systems from other regions of the US to establish what controls the various aspects of nutrient dynamics in rivers. Our results from the GYA, in addition to Midwest and Southwest US rivers, will provide water quality managers with new strategies for improving water quality downstream, and clarify mechanisms controlling nutrient retention in rivers.

The benthic geochemical record of late Holocene carbon flux in the northeast Atlantic

1995 ◽  
Vol 348 (1324) ◽  
pp. 221-227 ◽  
Keyword(s):  
Organic Carbon ◽  
Carbon Flux ◽  
Late Holocene ◽  
Sediment Accumulation ◽  
Euphotic Zone ◽  
Natural Uranium ◽  
Water Interface ◽  
Northeast Atlantic ◽  
Organic Carbon Flux ◽  
Organic Carbon Burial

This study centered around a transect of high-resolution (multi) cores from the 20° W meridian, 60-18° N in the northeast Atlantic. It spans a range of primary productivity zones, and was used to quantify and examine the vertical flux of organic carbon from the euphotic zone (50 m deep) to the sediment—water interface, through the sediment mixed layer, to burial in late Holocene sediment. The disequilibrium between members of the natural uranium decay series ( 226 Ra, 210 Pb and 210 Po) - which track the biogenic flux through scavenging of the particle-reactive nuclides —was employed. Together with experimentally and observationally derived factors, these data were used to convert nuclide flux to organic carbon flux resulting in an estimate of the water column flux of organic carbon. At the sediment-water interface micro-oxygen electrodes were used to quantify the consumption of organic carbon by aerobic respiration. It was noted that the estimated organic carbon flux is strongly dependent on the intensity of bioturbation. The late Holocene organic carbon burial flux was calculated for selected cores from measured organic carbon profiles and sediment accumulation rates over approximately the last 10000 years. This combined approach reveals a strong spatial and temporal signal in the flux of organic carbon through the deep sea in the northeast Atlantic, and provides additional insight into the fate of carbon in this area of the ocean.

A model for the light-limited growth of buoyant phytoplankton in a shallow, turbid waterbody

1994 ◽  
Vol 45 (5) ◽  
pp. 847 ◽  
Author(s):  
BE Sherman ◽  
IT Webster
Keyword(s):  
Wind Speed ◽  
Water Column ◽  
Chlorophyll Concentration ◽  
Light Attenuation ◽  
Euphotic Zone ◽  
Limited Growth ◽  
Potential Growth ◽  
Column Temperature ◽  
Turbid Waters ◽  
Neutrally Buoyant

A computer model was used to explore the relationship between buoyancy and the light-limited growth of phytoplankton in very turbid waters. The model simulates the potential growth of phytoplankton as a function of flotation speed, using field observations of photosynthetically active radiation, wind speed, surface-layer thickness (from water-column temperature data), and light attenuation made at Rushy Billabong on the River Murray from 28 November 1991 to 26 March 1992. A unique feature of the model is the simulation of the development and dispersal of surface scums as a function of wind speed. Under nutrient-replete conditions, the model predicted that phytoplankton with a flotation speed of 1-10 m day-1 (typical of Anabaena flos-aquae and Microcystis aeruginosa) would grow up to four times faster than would neutrally buoyant phytoplankton with the same maximum specific growth rate. In the shallow system modelled, high flotation speeds allowed a large proportion of the total population to rise into the euphotic zone shortly after the onset of stratification each day. Surface scums played an important role in maintaining the more buoyant phytoplankton populations close to the water surface. Under the very turbid conditions in the billabong (100 nephelometric turbidity units), self-shading became significant only when the mean chlorophyll concentration in the water column approached 100 mg chla m-3.

scholarly journals Storage of Fine Woodchips from a Medium Rotation Coppice Eucalyptus Plantation in Central Italy

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2355 ◽  
Author(s):  
Luigi Pari ◽  
Simone Bergonzoli ◽  
Paola Cetera ◽  
Paolo Mattei ◽  
Vincenzo Alfano ◽  
...  
Keyword(s):  
Energy Production ◽  
Dry Matter ◽  
Central Italy ◽  
Woody Biomass ◽  
Eucalyptus Plantation ◽  
High Productivity ◽  
Eucalyptus Wood ◽  
Storage Methods ◽  
Fuel Characteristics ◽  
Increasing Demand

Eucalyptus spp. has received attention from the research and industrial field as a biomass crop because of its fast growth and high productivity. The features of this species match with the increasing demand for wood for energy production. Commonly, the wood used for energy production is converted in chips, a material susceptible to microbial degradation and energy losses if not properly stored before conversion. This study aims at investigating two outdoor storage systems of Eucalyptus wood chips (covered vs. uncovered), assessing the variation in moisture content, dry matter losses and fuel characteristics. The class size of the material was P16, which was obtained using a commercial chipper appositely searched to conduct the study. The results highlighted how the different storage methods were influenced by the climatic condition: the woody biomass covered showed the best performances in terms of dry matter losses achieving 2.7% losses vs. the 8.5% of the uncovered systems. However, fuel characteristics displayed minor changes that affected the final energy balance (∆En = −0.2% in covered; ∆En = −6.17% in uncovered). Particle size varied in both methods with respect to the start conditions, but the variation was not enough to determine a class change, which remained P16 even after storage.

Influence of extended water column mixing during the first 2 years of hypolimnetic oxygenation on the phytoplankton community of Amisk Lake, Alberta

1997 ◽  
Vol 54 (9) ◽  
pp. 2133-2145 ◽  
Author(s):  
D J Webb ◽  
R D Robarts ◽  
E E Prepas
Keyword(s):  
Water Column ◽  
Trophic Status ◽  
Phytoplankton Community ◽  
Euphotic Zone ◽  
Open Water ◽  
Eutrophic Lake ◽  
Cyanobacterial Blooms ◽  
Chl A ◽  
Hypolimnetic Oxygenation ◽  
Physical Variables

The phytoplankton community, physical variables, and nutrient and chlorophyll a (Chl a) concentrations were monitored during the first two of six open-water seasons of hypolimnetic oxygenation in double-basined Amisk Lake, Alberta. Deep mixing of the water column in the treated basin (Zmax = 34 m) in spring was enhanced by hypolimnetic oxygenation. Oxygenation began in June 1988, when stratification was likely already established, but subsequent year-round treatment favoured an extended spring diatom bloom (Asterionella formosa and Cyclotella spp.), followed by a delay in the development of, and reduction in the severity of, cyanobacterial blooms (Aphanizomenon flos-aquae and Anabaena flos-aquae) in 1989. Historically, mean summer Chl a and total phosphorus (TP) concentrations in the euphotic zone (0-6 m) of the treated basin were 15.9 ± 1.6 and 33.5 ± 1.5 µg ·L-1, respectively, indicating a eutrophic lake. In 1988 and 1989, mean summer Chl a (10.0 ± 0.6 and 8.1 ± 0.7 µg ·L-1, respectively) and TP concentrations (29.0 ± 0.5 and 22.5 ± 0.9 µg ·L-1, respectively) in this stratum were lower than historic values (P < 0.05), indicating that the trophic status of Amisk Lake had shifted towards mesotrophy.

Nitrogen, Phosphorus, and Organic Carbon Cycling in an Arctic Lake

1985 ◽  
Vol 42 (4) ◽  
pp. 797-808 ◽  
Author(s):  
S. C. Whalen ◽  
J. C. Cornwell
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Water Column ◽  
Cold Water ◽  
Nutrient Retention ◽  
Overlying Water ◽  
Organic C ◽  
Outlet Stream ◽  
Organic Carbon Cycling ◽  
Nitrogen Phosphorus

Budgets for nitrogen, phosphorus, and organic carbon in Toolik Lake, Alaska, were assembled from data collected during 1977–81. The annual total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) loads to the Sake were 8557, 290, and 4.64 mmol∙m−2. Inlet streams were the major source of nutrients to the lake, as direct precipitation provided only 1, 2, and 5%, respectively, of the annual TOC, TN, and TP loads to the lake. Up to 30% of the annual N and P inputs to the lake from riverine sources occurred during the first 10 d of stream flow following breakup when cold water temperatures and snow-covered ice limited primary production. Due to the short water renewal time (0.5 yr), efficiency of nutrient retention was poor and 90, 82, and 70% of the annual TOC, TN, and TP inputs to the lake were discharged at the outlet stream. Regeneration within the water column supplied 40–66% and 68–78% of the N and P necessary for measured primary production. Yearly accumulation rates for C, N, and P in the sediment were about 220, 21.0, and 1.75 mmol∙m−2. Phosphorus remineralized within the sediment was completely retained due to adsorption onto Fe oxide minerals in the oxidizing surface layer. Annual rates of release of C and N to the overlying water column were 110 and 11.5–22.2 mmol∙m2. Mass balance considerations showed no serious errors in estimates of any terms of the annual sediment and water column N, P, and organic C budgets.

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