scholarly journals The Ballast Effect in the Indian Ocean

2017 ◽  
Author(s):  
Tim Rixen ◽  
Birgit Gaye ◽  
Kay-Christian Emeis ◽  
Venkitasubramani Ramaswamy
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Primary Production ◽  
Sediment Trap ◽  
Deep Sea ◽  
Carbon Flux ◽  
Arabian Sea ◽  
Co2 Uptake ◽  
Relative Importance ◽  
Organic Carbon Flux

Abstract. In this study, data obtained from a sediment trap experiments off South Java are analyzed and compared to satellite-derived information on primary production and data collected by deep-moored sediment traps in the Arabian Sea and the Bay of Bengal. The aim was to study the relative importance of primary production and the ballast effect on the organic carbon export and the CO2 uptake of the biological carbon pumps. Therefore, data obtained from sediment trap experiments carried out in other ocean basins were also integrated into the data analysis and a four-box model was developed. Our data showed that the organic carbon flux in the highly-productive upwelling system in the Arabian Sea was similar to those in the low productive system off South Java. Off South Java as in other river-influenced regions, lithogenic matter supplied from land mainly controls the organic carbon flux via its ballast effect in sinking particles, whereas carbonate produced by marine organisms appears to be the main ballast material in the high productive regions. Since the carbonate flux tends to increase with an increasing export production, it is difficult to quantify the relative importance of productivity and the ballast effect on the organic carbon flux into the deep sea. However, the export of organic matter into the deep sea represents a loss of nutrients for the pelagic ecosystems, which needs to be balanced by mode water nutrient supply into the seasonal thermocline to sustain the productivity of the pelagic system. The amount of preformed nutrients utilized during the formation of the exported organic matter strongly influences the impact of the ballast effect on the CO2 uptake of the organic carbon pump. Accordingly, this is stronger at higher latitudes where preformed nutrients are formed than at lower latitudes where the euphotic zone is nutrient depleted. Nevertheless, the ballast effect enhances the export of organic matter into the deep sea and favors the sedimentation of organic matter in river-influenced regions. Since globally > 80 % of organic carbon burial occurs in river-dominated systems, the lithogenic ballast is assumed to play an important role in the Earth’s climate system on geological time scales.

scholarly journals Sinking rates and ballast composition of particles in the Atlantic Ocean: implications for the organic carbon fluxes to the deep ocean

2009 ◽  
Vol 6 (1) ◽  
pp. 85-102 ◽  
Author(s):  
G. Fischer ◽  
G. Karakaş
Keyword(s):  
Organic Carbon ◽  
Atlantic Ocean ◽  
Sediment Trap ◽  
Carbon Flux ◽  
Coastal Upwelling ◽  
Production Systems ◽  
Deep Ocean ◽  
Biogeochemical Model ◽  
Carbonate Content ◽  
Organic Carbon Flux

Abstract. The flux of materials to the deep sea is dominated by larger, organic-rich particles with sinking rates varying between a few meters and several hundred meters per day. Mineral ballast may regulate the transfer of organic matter and other components by determining the sinking rates, e.g. via particle density. We calculated particle sinking rates from mass flux patterns and alkenone measurements applying the results of sediment trap experiments from the Atlantic Ocean. We have indication for higher particle sinking rates in carbonate-dominated production systems when considering both regional and seasonal data. During a summer coccolithophorid bloom in the Cape Blanc coastal upwelling off Mauritania, particle sinking rates reached almost 570 m per day, most probably due the fast sedimentation of densely packed zooplankton fecal pellets, which transport high amounts of organic carbon associated with coccoliths to the deep ocean despite rather low production. During the recurring winter-spring blooms off NW Africa and in opal-rich production systems of the Southern Ocean, sinking rates of larger particles, most probably diatom aggregates, showed a tendency to lower values. However, there is no straightforward relationship between carbonate content and particle sinking rates. This could be due to the unknown composition of carbonate and/or the influence of particle size and shape on sinking rates. It also remains noticeable that the highest sinking rates occurred in dust-rich ocean regions off NW Africa, but this issue deserves further detailed field and laboratory investigations. We obtained increasing sinking rates with depth. By using a seven-compartment biogeochemical model, it was shown that the deep ocean organic carbon flux at a mesotrophic sediment trap site off Cape Blanc can be captured fairly well using seasonal variable particle sinking rates. Our model provides a total organic carbon flux of 0.29 Tg per year down to 3000 m off the NW African upwelling region between 5 and 35° N. Simple parameterisations of remineralisation and sinking rates in such models, however, limit their capability in reproducing the flux variation in the water column.

scholarly journals Fluvial organic carbon flux from an eroding peatland catchment, southern Pennines, UK

2008 ◽  
Vol 12 (2) ◽  
pp. 625-634 ◽  
Author(s):  
R. R. Pawson ◽  
D. R. Lord ◽  
M. G. Evans ◽  
T. E. H. Allott
Keyword(s):  
Organic Carbon ◽  
Carbon Flux ◽  
Relative Importance ◽  
Carbon Export ◽  
Event Scale ◽  
Organic Carbon Flux ◽  
Poc Export ◽  
Event Based ◽  
First Time ◽  
Annual Flux

Abstract. This study investigates for the first time the relative importance of dissolved organic carbon (DOC) and particulate organic carbon (POC) in the fluvial carbon flux from an actively eroding peatland catchment in the southern Pennines, UK. Event scale variability in DOC and POC was examined and the annual flux of fluvial organic carbon was estimated for the catchment. At the event scale, both DOC and POC were found to increase with discharge, with event based POC export accounting for 95% of flux in only 8% of the time. On an annual cycle, exports of 35.14 t organic carbon (OC) are estimated from the catchment, which represents an areal value of 92.47 g C m−2 a−1. POC was the most significant form of organic carbon export, accounting for 80% of the estimated flux. This suggests that more research is required on both the fate of POC and the rates of POC export in eroding peatland catchments.

scholarly journals The ballast effect of lithogenic matter and its influences on the carbon fluxes in the Indian Ocean

2019 ◽  
Vol 16 (2) ◽  
pp. 485-503 ◽  
Author(s):  
Tim Rixen ◽  
Birgit Gaye ◽  
Kay-Christian Emeis ◽  
Venkitasubramani Ramaswamy
Keyword(s):  
Indian Ocean ◽  
Organic Carbon ◽  
Spatial Variability ◽  
Primary Production ◽  
Carbon Flux ◽  
Carbon Fluxes ◽  
Matter Content ◽  
Organic Carbon Flux ◽  
The Indian Ocean ◽  
Organic Carbon Fluxes

Abstract. Data obtained from long-term sediment trap experiments in the Indian Ocean in conjunction with satellite observations illustrate the influence of primary production and the ballast effect on organic carbon flux into the deep sea. They suggest that primary production is the main control on the spatial variability of organic carbon fluxes at most of our study sites in the Indian Ocean, except at sites influenced by river discharges. At these sites the spatial variability of organic carbon flux is influenced by lithogenic matter content. To quantify the impact of lithogenic matter on the organic carbon flux, the densities of the main ballast minerals, their flux rates and seawater properties were used to calculate sinking speeds of material intercepted by sediment traps. Sinking speeds in combination with satellite-derived export production rates allowed us to compute organic carbon fluxes. Flux calculations imply that lithogenic matter ballast increases organic carbon fluxes at all sampling sites in the Indian Ocean by enhancing sinking speeds and reducing the time of organic matter respiration in the water column. We calculated that lithogenic matter content in aggregates and pellets enhances organic carbon flux rates on average by 45 % and by up to 62 % at trap locations in the river-influenced regions of the Indian Ocean. Such a strong lithogenic matter ballast effect explains the fact that organic carbon fluxes are higher in the low-productive southern Java Sea compared to the high-productive western Arabian Sea. It also implies that land use changes and the associated enhanced transport of lithogenic matter from land into the ocean may significantly affect the CO2 uptake of the organic carbon pump in the receiving ocean areas.

scholarly journals FORAMINÍFEROS BENTÓNICOS RECIENTES EN SEDIMENTOS DE FONDO DE LA CUENCA DE PANAMÁ (PACÍFICO COLOMBIANO), COMO INDICADORES DE PRODUCTIVIDAD Y OXIGENACIÓN

2016 ◽  
Vol 32 ◽  
Author(s):  
Maria Julliet Betancur ◽  
Ignacio Martínez
Keyword(s):  
Organic Carbon ◽  
Deep Sea ◽  
Carbon Flux ◽  
Size Fraction ◽  
Low Oxygen ◽  
High Concentration ◽  
Organic Carbon Flux ◽  
Matter Flux ◽  
Costa Rica Dome ◽  
Foraminíferos Bentónicos

Thirteen deep-sea samples (core-tops) from the Panama Basin, Colombian Pacific, were analysed for benthonic foraminifera in the >150μm size fraction. Based on the microfaunal content, three zones are recognised in the Panama Basin: (1) northern euphrophic region (~8º to 5,5ºN), characterized by a high concentration of organic matter flux to the seafloor, oxygenated sediments, and influence of the Panama Bight and the Costa Rica Dome upwelling systems, (2) mesotrophic region (~5,5 to 2ºN), characterized by low fluxes of organic carbon to the seafloor, oxygenated sediments, terrigenous influence and fluctuations of the upwelling systems of the basin, and (3) southern euphotic region (south of ~2ºN), characterized by a larger organic carbon flux to the seafloor, low oxygen content (disoxia) and influence of the Equatorial Divergence.

scholarly journals The Ballast Effect of Lithogenic Matter and its Influences on the Carbon Fluxes in the Indian Ocean

2018 ◽  
Author(s):  
Tim Rixen ◽  
Birgit Gaye ◽  
Kay-Christian Emeis ◽  
Venkitasubramani Ramaswamy
Keyword(s):  
Organic Matter ◽  
Indian Ocean ◽  
Organic Carbon ◽  
Deep Sea ◽  
Carbon Fluxes ◽  
Co2 Uptake ◽  
Surface Ocean ◽  
Carbon Pump ◽  
The Indian Ocean ◽  
The Impact

Abstract. Data obtained from long-term sediment trap experiments in the Indian Ocean were analysed in conjunction with satellite-derived observations and results obtained from a box model to study the influence of primary production and the ballast effect on organic carbon flux into the deep sea. The results are used to better understand the associated impacts on the CO2 uptake of the organic carbon pump. In line with other findings derived from global data sets, our results suggest that a preferential export of organic matter in slower-sinking particles reduces the transfer efficiency of exported organic matter in high-productive systems compared with low-productive regions. The resulting enhanced respiration of organic matter maintains the high nutrient availability in the surface ocean and thus the high productivity during the summer and winter bloom in the Arabian Sea. In turn, mineral ballast is essential for the transport of organic matter and nutrients into the deep sea. The additional lithogenic ballast effect can increase organic carbon fluxes by 60 %. Our model results indicate that lithogenic ballast enhances the CO2 uptake of the organic carbon pump by increasing the amount of nutrients utilised by the organic carbon pump to bind CO2. By enhancing the export of organic matter into the deep sea, the ballast effect increases the residence time of these nutrients in the ocean. They lose the attached CO2 if they are introduced into the surface ocean at higher latitude, where the lack of light prevents photosynthesis in winter. Considering the impact of the lithogenic ballast effect on the organic carbon export into the deep sea and the enhanced mobilisation of lithogenic matter due to land-use changes, it is assumed that humans influence the CO2 uptake of the organic carbon pump, which might hold relevance for the discussion about the anthropogenic CO2 uptake of the ocean.

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