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

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.

1978 ◽  
Vol 35 (8) ◽  
pp. 1089-1094 ◽  
Author(s):  
L. de March

The sediments of Char Lake, Resolute, Northwest Territories, were studied to determine storage rates of nitrogen, phosphorus, and organic carbon which could be compared with retention estimates of N and P and primary production and respiration estimates for organic C. The storage rate for P (0.018 g∙m−2∙yr−1) was 129% of measured retention, storage of N (0.087 g∙m−2∙yr−1) was 43% of measured retention, and the 1 g∙m−2∙yr−1 storage estimate for organic C was 18% of the difference between primary production and respiration. Lacustrine sediments were found to be very unevenly distributed with accumulations from 7 cm to an estimated 3 m in the last 6200 yr and to vary in N, P, and organic C concentrations from place to place. Key words: sedimentation, nutrient budgets, arctic, lake, carbon, nitrogen, phosphorus


2016 ◽  
Author(s):  
Jun Liu ◽  
Lex Bouwman ◽  
Jiaye Zang ◽  
Chenying Zhao ◽  
Xiaochen Liu ◽  
...  

Abstract. Silicon (Si) and carbon (C) play key roles in the river and marine biogeochemistry. The Si and C budgets for the Bohai Sea were established on the basis of measurements at a range of stations and additional data from the literature. The results show that the spatial distributions of reactive Si and organic C (OC) in the water column are largely affected by the riverine input, primary production and export to the Yellow Sea. Biogenic silica (BSi) and total OC in sediments are mainly from marine primary production. The major supply of dissolved silicate (DSi) comes from benthic diffusion, riverine input alone accounts for 17 % of reactive Si inputs to the Bohai Sea; the dominant DSi removal from the water column is diatom uptake, followed by sedimentation. Rivers contribute 47 % of exogenous OC inputs to the Bohai Sea; the dominant outputs of OC are sedimentation and export to the Yellow Sea. The net burial of BSi and OC represent 3.3 % and 1.0 % of total primary production, respectively. Primary production has increased by 10 % since 2002 as a result of increased river loads of DSi and BSi. Our findings underline the critical role of riverine Si supply in primary production in coastal marine ecosystems.


1995 ◽  
Vol 32 (3) ◽  
pp. 203-209 ◽  
Author(s):  
P. W. Adcock ◽  
G. L. Ryan ◽  
P. L. Osborne

A constructed, clay-based, surface flow wetland located in Byron Bay, New South Wales, Australia, was studied to determine the relative importance of living plant tissue, plant litter, sediment, and the water column as nutrient stores. The nitrogen, phosphorus and carbon contents of each nutrient compartment were determined throughout the wetland. The nitrogen and phosphorus content of the plants was higher at the inlet end of the wetland and declined with distance away from it. Nutrient levels in the sediment and water column did not vary significantly with distance through the wetland. Phosphorus concentrations in the sediments were high, but plants were shown to be responsible for the majority of nutrient accumulation from this system. The plants had failed to penetrate the clay substrate and a solid mat of adventitious roots had developed in the overlying water. In essence the plants, mainly grasses, were growing hydroponically.


2013 ◽  
Vol 10 (4) ◽  
pp. 2787-2801 ◽  
Author(s):  
A.-J. Cavagna ◽  
F. Dehairs ◽  
S. Bouillon ◽  
V. Woule-Ebongué ◽  
F. Planchon ◽  
...  

Abstract. The combination of concentrations and δ13C signatures of Particulate Organic Carbon (POC) and sterols provides a powerful approach to study ecological and environmental changes in both the modern and ancient ocean. We applied this tool to study the biogeochemical changes in the modern ocean water column during the BONUS-GoodHope survey (February–March 2008) from Cape Basin to the northern part of the Weddell Gyre. Cholesterol and brassicasterol were chosen as ideal biomarkers of the heterotrophic and autotrophic carbon pools, respectively, because of their ubiquitous and relatively refractory nature. We document depth distributions of concentrations (relative to bulk POC) and δ13C signatures of cholesterol and brassicasterol combined with CO2 aq. surface concentration variation. While the relationship between CO2 aq. and δ13C of bulk POC and biomarkers have been reported by others for the surface water, our data show that this persists in mesopelagic and deep waters, suggesting that δ13C signatures of certain biomarkers in the water column could be applied as proxies for surface water CO2 aq. We observed a general increase in sterol δ13C signatures with depth, which is likely related to a combination of particle size effects, selective feeding on larger cells by zooplankton, and growth rate related effects. Our data suggest a key role of zooplankton fecal aggregates in carbon export for this part of the Southern Ocean (SO). Additionally, in the southern part of the transect south of the Polar Front (PF), the release of sea-ice algae during the ice demise in the Seasonal Ice Zone (SIZ) is hypothesized to influence the isotopic signature of sterols in the open ocean. Overall, the combined use of δ13C values and concentrations measurements of both bulk organic C and specific sterols throughout the water column offers the promising potential to explore the recent history of plankton and the fate of organic matter in the SO.


2012 ◽  
Vol 9 (2) ◽  
pp. 1667-1709 ◽  
Author(s):  
A.-J. Cavagna ◽  
F. Dehairs ◽  
V. Woule-Ebongué ◽  
S. Bouillon ◽  
F. Planchon ◽  
...  

Abstract. The combination of concentrations and δ13C signatures of Particulate Organic Carbon (POC) and sterols provides a powerful approach to study ecological and environmental changes both in the modern and ancient ocean, but its application has so far been restricted to the surface area. We applied this tool to study the biogeochemical changes in the modern ocean water column during the BONUS-GoodHope survey (Feb–Mar 2008) from Cape Basin to the northern part of the Weddell Gyre. Cholesterol and brassicasterol were chosen as ideal biomarkers of the heterotrophic and autotrophic carbon pools, respectively, because of their ubiquitous and relatively refractory nature. We document depth distributions of concentrations (relative to bulk POC) and δ13C signatures of cholesterol and brassicasterol from the Cape Basin to the northern Weddell Gyre combined with CO2 aq. surface concentration variation. While relationships between surface water CO2 aq. and δ13C of bulk POC and biomarkers have been previously established for surface waters, our data show that these remain valid in deeper waters, suggesting that δ13C signatures of certain biomarkers could be developed as proxies for surface water CO2 aq. Our data suggest a key role of zooplankton fecal aggregates in carbon export for this part of the Southern Ocean. We observed a general increase in sterol δ13C signatures with depth, which is likely related to a combination of particle size effects, selective feeding on larger cells by zooplankton, and growth rate related effects Additionally, in the southern part of the transect south of the Polar Front (PF), the release of sea-ice algae is hypothesized to influence the isotopic signature of sterols in the open ocean. Overall, combined use of δ13C and concentrations measurements of both bulk organic C and specific sterol markers throughout the water column shows the promising potential of analyzing δ13C signatures of individual marine sterols to explore the recent history of plankton and the fate of organic matter in the SO.


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