The potential of seaweed cultivation to achieve carbon neutrality and mitigate deoxygenation and eutrophication

Abstract Carbon neutrality has been proposed due to the increasing concerns about the consequences of rising atmospheric CO2. Previous studies overlooked the role of lost particle organic carbon (POC) and excreted dissolved organic carbon (DOC) from seaweed cultivation in carbon sequestration, that is to say, long term carbon storage in the oceanic sediments and in the water. This study assessed the potential of seaweed cultivation to achieve carbon neutrality of China by 2060 using a new method that included lost POC and excreted DOC. Based on the seaweed production in the years 2015-2019 in China, harvested seaweed removed 605,193 tonnes of carbon, 70,304 tonnes of nitrogen and 8,619 tonnes of phosphorus from seawaters annually; farmed seaweed sequestrated 343,766 tonnes of carbon and generated 2530,558 tonnes of oxygen annually. Among the seven farmed seaweeds, Gracilariopsis lemaneiformis has the highest capacities for carbon removal (9.58 tonnes ha-1 yr-1) and sequestration (5.44 tonnes ha-1 yr-1) and thus has the smallest cultivation area required to sequestrate 2.5 Gt CO2 that is annually required to achieve China's carbon neutrality goal by 2060. The O2 generated by seaweed cultivation could increase dissolved oxygen in seawaters (0-3 m deep) by 21% daily, which could effectively counteract deoxygenation in seawaters. Gracilariopsis lemaneiformis also has the highest N removal capacity while Saccharina japonica has the highest P removal capacity. To completely absorb the N and P released from the fish mariculture, a production level or a cultivation area two and three times larger (assuming productivity remains unchanged) would be required. This study indicates that seaweed cultivation could play an important role in achieving carbon neutrality and mitigating deoxygenation and eutrophication in seawaters. Cultivation cost could be offset to some extent by increased sales of the harvest parts of the seaweed for food and biofuel.

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Phytolith-occluded organic carbon as a mechanism for long-term carbon sequestration in a typical steppe: The predominant role of belowground productivity

The Science of The Total Environment ◽

10.1016/j.scitotenv.2016.10.206 ◽

2017 ◽

Vol 577 ◽

pp. 413-417 ◽

Cited By ~ 12

Author(s):

Limin Qi ◽

Frank Yonghong Li ◽

Zhangting Huang ◽

Peikun Jiang ◽

Taogetao Baoyin ◽

...

Keyword(s):

Carbon Sequestration ◽

Organic Carbon ◽

Predominant Role ◽

Typical Steppe ◽

Belowground Productivity

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The role of clay, organic carbon and long-term management on mouldboard plough draught measured on the Broadbalk wheat experiment at Rothamsted

Soil Use and Management ◽

10.1111/j.1475-2743.2006.00054.x ◽

2006 ◽

Vol 22 (4) ◽

pp. 334-341 ◽

Cited By ~ 47

Author(s):

C. W. Watts ◽

L. J. Clark ◽

P. R. Poulton ◽

D. S. Powlson ◽

A. P. Whitmore

Keyword(s):

Organic Carbon ◽

Mouldboard Plough ◽

Term Management

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Exploring the Growing Role of Terrestrial Carbon Across North Atlantic Fjords

10.5194/egusphere-egu2020-9393 ◽

2020 ◽

Author(s):

Craig Smeaton ◽

William Austin

Keyword(s):

Organic Carbon ◽

Marine Environment ◽

North Atlantic ◽

Planetary Science ◽

Terrestrial Environment ◽

Carbon Burial ◽

Organic Carbon Burial ◽

Fjord Sediments

Fjords are recognized as globally significant hotspots for the burial (Smith et al., 2015) and long-term storage (Smeaton et al., 2017) of marine and terrestrially derived organic carbon (OC). By trapping and locking away OC over geological timescales, fjord sediments provide a potentially important yet largely overlooked climate regulation service. The proximity of fjords to the terrestrial environment in combination with their geomorphology and hydrography results in the fjordic sediments being subsidized with organic carbon (OC) from the terrestrial environment. This terrestrial OC (OCterr) transferred to the marine environment has traditionally be considered lost to the atmosphere in the form of CO2 in most carbon (C) accounting schemes yet globally it is estimated that 55% of OC trapped in fjord sediments is derived from terrestrial sources (Cui et al., 2016). So is this terrestrial OC truly lost? Here, we estimate the quantity of OCterr held within North Atlantic fjords with the aim of better understanding the recent and long-term role of the terrestrial environment in the evolution of these globally significant sedimentary OC stores. By understanding this subsidy of OC from the terrestrial to the marine environment we can take the first steps in quantifying the terrestrial OC stored in fjords and the wider coastal marine environment.Cui, X., Bianchi, T.S., Savage, C. and Smith, R.W., 2016. Organic carbon burial in fjords: Terrestrial versus marine inputs.&#160;Earth and Planetary Science Letters,&#160;451, pp.41-50.Smeaton, C., Austin, W.E., Davies, A., Baltzer, A., Howe, J.A. and Baxter, J.M., 2017. Scotland's forgotten carbon: a national assessment of mid-latitude fjord sedimentary stocks.&#160;Biogeosciences.Smith, R.W., Bianchi, T.S., Allison, M., Savage, C. and Galy, V., 2015. High rates of organic carbon burial in fjord sediments globally.&#160;Nature Geoscience,&#160;8(6), p.450.&#160;

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Effects of long-term irrigation with treated wastewater. Part II: Role of organic carbon on Cu, Pb and Cr behaviour

Applied Geochemistry ◽

10.1016/j.apgeochem.2010.09.002 ◽

2010 ◽

Vol 25 (11) ◽

pp. 1711-1721 ◽

Cited By ~ 12

Author(s):

Lobna Tarchouna Gharbi ◽

Patricia Merdy ◽

Yves Lucas

Keyword(s):

Organic Carbon ◽

Treated Wastewater

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The role of iron in the diagenesis of organic carbon and nitrogen in sediments: A long-term incubation experiment

Marine Chemistry ◽

10.1016/j.marchem.2014.02.007 ◽

2014 ◽

Vol 162 ◽

pp. 1-9 ◽

Cited By ~ 23

Author(s):

Andrew Barber ◽

Karine Lalonde ◽

Alfonso Mucci ◽

Yves Gélinas

Keyword(s):

Organic Carbon ◽

Incubation Experiment ◽

Carbon And Nitrogen

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WATER-STABLE AGGREGATION IN RELATION TO VARIOUS CROPPING ROTATIONS AND SOIL CONSTITUENTS

Canadian Journal of Soil Science ◽

10.4141/cjss65-027 ◽

1965 ◽

Vol 45 (2) ◽

pp. 189-197 ◽

Cited By ~ 4

Author(s):

M. N. Malik ◽

D. S. Stevenson ◽

G. C. Russell

Keyword(s):

Organic Carbon ◽

Cropping Systems ◽

Soil Aggregates ◽

Aggregate Stability ◽

The Other ◽

Soluble Salts ◽

Soil Aggregate Stability ◽

Soil Constituents

The effects of four cropping systems on water-stable aggregation were compared. Two methods of wetting the soil, (1) by capillarity and (2) under vacuum prior to wet-sieving, were also compared. Various soil constituents were determined to assess their roles in the promotion of granulation and stability. Water-stable aggregation in grassland was significantly higher than in the other three long-term rotations, corn once in 9 years, continuous wheat, and 4 years alfalfa in 10 years. No significant differences in water-stable aggregation were found among the other three rotations.Wetting the soil by capillarity was judged to give a better index of soil aggregate stability than wetting under vacuum. Organic carbon and stable aggregation were positively correlated in the grassland soil and in the soil of the cultural treatments combined over all depths, suggesting an important role of organic matter in stabilization of soil aggregates. It is pointed out, however, that in cultivated soils the cultivation or the type of root system of the crops may override the influence of the organic carbon. Total soluble salts were positively correlated with aggregation in a few treatments.

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The Role of Dissolved Organic Carbon in a Shallow Lowland Reservoir Ecosystem — A Long-term Study

Acta hydrochimica et hydrobiologica ◽

10.1002/aheh.200390001 ◽

2002 ◽

Vol 30 (4) ◽

pp. 179-189 ◽

Cited By ~ 12

Author(s):

Andrzej Górniak ◽

Piotr Zieliński ◽

Elżbieta Jekatierynczuk-Rudczyk ◽

Magdalena Grabowska ◽

Tomasz Suchowolec

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Term Study ◽

Long Term Study ◽

Lowland Reservoir

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David Stewart Jenkinson. 25 February 1928 — 16 February 2011

Biographical Memoirs of Fellows of the Royal Society ◽

10.1098/rsbm.2017.0007 ◽

2017 ◽

Vol 63 ◽

pp. 377-411

Author(s):

David Powlson ◽

Phil Brookes

Keyword(s):

Organic Matter ◽

Microbial Biomass ◽

Organic Carbon ◽

Nitrogen Fertilizer ◽

Management Practices ◽

Soil Microbial Biomass ◽

Soil Microbial ◽

Long Term Experiments

David Jenkinson was one of the most influential soil scientists of his generation, bringing new insights into the transformations of organic matter and nitrogen in soil. He spent the majority of his career at Rothamsted Research, Harpenden, UK. His studies were influential regarding the role of soil carbon stocks in the context of climate change and the role of nitrogen fertilizer in delivering adequate supplies of food for a growing world population. His research encompassed both fundamental studies on soil processes and immensely practical applications of this knowledge, often utilizing the Rothamsted long-term experiments that have run for over 170 years. He is particularly well known for his development of a method for determining the quantity of organic carbon held in the cells of living micro-organisms in soil, termed the ‘soil microbial biomass’. This breakthrough opened the way for a new wave of soil biological research. David developed one of the earliest computer models for the turnover of organic carbon in soil, known as the Rothamsted Carbon Model, RothC. This model, conceptually very simple, has proved highly successful in simulating and predicting changes in soil organic carbon (SOC) content under different management practices worldwide, being used by over 2600 people in 115 countries. His research using the stable isotope of nitrogen, 15 N, in large-scale field experiments drew attention to the factors leading to inefficiencies in the use of nitrogen fertilizer but also demonstrated that it is possible to achieve high efficiency if good agricultural management practices are followed. It also demonstrated, more clearly than previously, the great importance of soil organic matter as a source of nitrogen for crops and the role of the soil microbial biomass both in immobilizing a proportion of applied fertilizer nitrogen and also in causing confusion in the interpretation of such experiments. By calculating nitrogen budgets for the Rothamsted long-term experiments he quantified the deposition of nitrogen compounds from atmosphere to land, laying foundations for later studies concerning the ecological and agricultural impacts of this significant input of nitrogen.

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