Method for improving carbon sequestration and sink increase effects by constructing aquatic plant group by utilizing C4 aquatic plants

Abstract

The invention discloses a method for improving carbon sequestration and sink increase effects by constructing an aquatic plant group by utilizing C4 aquatic plants, which comprises the following steps: when lake aquatic vegetation restoration is carried out, in the step of planting the aquatic plants, the C4 aquatic plants or C4-like aquatic plants are synchronously planted, the C4 aquatic plants can be one or more of cyperus rotundus, echinochloa crusgalli, echinochloa crusgalli and spartina alterniflora, and the C4 aquatic plants can be one or more of echinochloa crusgalli or echinochloa crusgalli or echinochloa crusgalli. When CO2 in air is absorbed and assimilated, photosynthesis products of the C4-like aquatic plants are changed into C4 compounds, and the C4-like aquatic plants can be hydrilla or ottelia alismoides. By improving the photosynthesis rate, the growth rate and the biomass of wetland plant communities, the carbon sequestration and convergence increasing effects of lake wetland plants are improved. The lake carbon sequestration and sink increase effects can be remarkably improved, the method can be coupled and integrated with lake ecological restoration and lakeside wetland construction, and technical support is provided for carbon reduction.

Description

Technical Field

[0001] The present invention belongs to the field of water ecological environment, particularly to the field of ecological restoration of water bodies such as lakes and rivers. More specifically, it is a method for constructing an aquatic plant community using C4 aquatic plants to improve the carbon sequestration and sink enhancement effect of lakes. Background Art

[0002] As one of the important ecosystems on the earth, the carbon cycle process of wetlands is very important in the study of the global terrestrial ecosystem carbon cycle. Wetlands form carbon pools through the growth of wetland vegetation and the sequestration of organic matter in soil and silt, and its carbon sequestration rate is about 200 - 800 gC / m 2 / yr. Wetlands are mainly composed of anaerobic ecosystem types such as tidal flat wetlands, lakeshore wetlands, and swamp wetlands that are flooded for a long time, and have a high carbon sequestration function. Its annual organic carbon burial rate reaches 9 - 856.5 gC / m 2 / yr, which is 10 - 100 times that of the mature terrestrial forest ecosystem soil carbon sequestration rate (0.35 - 6.55 gC / m 2 / yr), and is known as one of the ecosystems with the highest global carbon sequestration rate, which has an important impact on maintaining the global carbon balance and climate stability. However, at present, many lake wetlands are degraded and the wetland carbon sink capacity is declining. There is an urgent need to develop technologies for improving the pollution reduction, carbon sequestration, and sink enhancement of lake wetlands.

[0003] Most of the carbon in the wetland ecosystem is stored in the bottom mud through the growth of vegetation, the burial of plant debris, and sediment deposition. On the one hand, wetlands have a high primary productivity, and after its litter and root exudates enter the bottom mud, it can increase the input of bottom mud organic matter; on the other hand, due to the effect of flooding, the anaerobic environment of the soil can inhibit the mineralization and decomposition of soil organic matter, which is conducive to the accumulation of soil carbon. Compared with other global terrestrial ecosystems, the proportion of carbon storage in the wetland ecosystem is relatively large, and more than half of the carbon will be stored in the sediment. It can be seen that wetland carbon fixation and burial are greatly related to the growth rate and biomass increase of wetland plants and the anaerobic environment of flooding.

[0004] C4 plants are often written as C4 plants. During their growth process, they first synthesize four-carbon compounds such as malic acid or aspartic acid by absorbing carbon dioxide from the air. C4 plants have high photosynthetic efficiency, strong reproductive ability, and high biomass, and can grow and spread rapidly in a short time. Therefore, they absorb and fix a large amount of atmospheric CO2 and bicarbonate in water. Based on this, using C4 aquatic plants to repair wetland plants and construct an aquatic plant community can greatly improve the plant biomass and increase the carbon sequestration and sink enhancement ability of lakes. Summary of the Invention

[0005] In view of the above problems, the present invention provides a method for constructing an aquatic plant community using C4 aquatic plants to enhance the carbon sequestration and sink function, aiming to effectively improve the carbon sequestration and sink capacity of lake wetlands.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A method for constructing an aquatic plant community using C4 aquatic plants to enhance the carbon sequestration and sink function, comprising the following steps: When carrying out the restoration of lake aquatic vegetation, in the step of planting aquatic plants, C4 aquatic plants or C4-like aquatic plants are planted synchronously. The C4-like aquatic plants are aquatic plants whose photosynthesis products change into C4 compounds when absorbing and assimilating CO2 in the air.

[0007] Further, the C4 aquatic plants are Cyperus papyrus ( Cyerus Papyrus ), Echinochloa crusgalli ( Echinochloa crusgalli ), Echinochloa caudata ( Echinochloa caudata ), or Spartina alterniflora ( Spartina alterniflora ) or one or more of them.

[0008] Further, the C4-like aquatic plants are Hydrilla verticillata ( Hydrilla verticillata ) or Ottelia alismoides ( Ottelia alismoides ).

[0009] C4 aquatic plants and C4-like aquatic plants have a fast growth rate, a large biomass, and a strong reproduction and diffusion ability, which can improve the species diversity and community stability of lake wetlands and achieve the purpose of increasing the carbon sequestration and sink capacity of lakes.

[0010] Hydrilla verticillata is a submerged plant of the Hydrocharitaceae family. When the external CO2 concentration decreases, it will cause the change of its photosynthetic pathway from C3 type to C4 type. This transformation does not require the plant to produce new leaves, but occurs under the original background. The C4 photosynthesis of Hydrilla verticillata is a single-cell type C4 that does not rely on the Kranz structure. Ottelia alismoides has three carbon concentration mechanisms, can use bicarbonate as the carbon source for photosynthesis, carry out the C4 photosynthetic pathway, and can carry out the crassulacean acid metabolism pathway (CAM) under low-carbon induction.

[0011] Further, the planting proportion of the C4 aquatic plants or C4-like aquatic plants in the planted area accounts for 20%-70% of the total biomass of all plants, which can increase the total biomass of the plant community by about 11%-50% and effectively ensure the improvement of the carbon sequestration and sink capacity of the wetland system.

[0012] Further, the C4 aquatic plants are a combination of Cyperus papyrus, Echinochloa caudata, and Spartina alterniflora.

[0013] Furthermore, when the planting ratio of the C4 aquatic plants in the planted area accounts for 20%-70% of the total plant biomass, and among the C4 aquatic plants, Cyperus papyrus accounts for 5%-20% of the biomass, Echinochloa caudata accounts for 5%-20% of the biomass, and Spartina alterniflora accounts for 10%-30% of the biomass.

[0014] Further, the C4 aquatic plants are planted on the shore or in the shoal where the water depth is below 60 cm. Further still, when the C4 aquatic plant is Cyperus papyrus, the planting water depth is below 40 cm; when the C4 aquatic plant is Echinochloa crusgalli or Echinochloa caudata, the planting water depth is below 30 cm; when the C4 aquatic plant is Spartina alterniflora, the planting water depth is below 50 cm.

[0015] Further, the C4-like aquatic plants are planted in the area where the water depth is 80 - 160 cm.

[0016] Advantages and effects of the present invention: Traditional ecological restoration of lake wetlands and aquatic vegetation mainly includes three aspects: habitat creation such as wetland substrate improvement, planting of common aquatic plants and optimization of community configuration, and community stabilization management and regulation. The technology of the present invention utilizes the biological physiological and ecological characteristics of C4 aquatic plants, such as fast growth rate, large biomass, and strong reproduction and diffusion ability, to improve and enhance the technology of aquatic plant planting and community optimization configuration. It significantly increases the plant biomass in lake wetlands and at the same time enhances the carbon sequestration and sink capacity of lakes. The implementation cost is low, the operation is simple and easy, and it is effective in the long term after the technology is implemented. It can be widely promoted on a large scale. It is not only applicable to carbon sequestration and carbon burial in lake wetlands, but also applicable to carbon sequestration and sink enhancement in rivers, providing technical support for the restoration of lakes and rivers and the improvement of carbon sink functions. Description of the drawings

[0017] In order to more clearly illustrate the technical solutions in the present invention, the following will briefly introduce the drawings required for the description of the prior art. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0018] Figure 1 This is the monitoring result of the wetland plant biomass in the technical demonstration area of the present invention from June to October.

[0019] Figure 2 This is the monitoring result of the wetland plant biomass in the control area of the present invention from June to October.

[0020] Figure 3 This is the comparison chart of the monitoring results of the wetland plant biomass in the technical demonstration area and the control area of the present invention from June to October. Detailed implementation manners

[0021] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments and drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Embodiment

[0022] In March 2022, first, a technical demonstration area and a control area mainly growing reeds ( Phragmites communi s), cattails ( Typha angustifolia ), and Cyperus iria ( Cyperus microiria were selected in Luodaying Wetland in Chaohu. The area for plant growth was 200 - 1000 m 2 .

[0023] Secondly, the areas of reeds, cattails, and Cyperus iria in the technical demonstration area were kept close to those in the control area, and the growth trends were not significantly different.

[0024] In the technical demonstration area, C4 aquatic plants were artificially configured: 200 m 2 of Echinochloa caudata and 500 m 2 of Cyperus papyrus, and then 1000 m 2 of Hydrilla verticillata was planted. In the control area, two C3 aquatic plants, Carex sp. 1 ( 2 sp.) and Carex sp. 2 ( Carex sp.), with an area of 400 m Carex each were planted, and then Vallisneria natans ( Vallisneria natans ), a C3 aquatic plant with the same area as Hydrilla verticillata, was planted.

[0025] From July to October 2022, the growth of aquatic plants in the above-mentioned technical demonstration area and control area was monitored to compare the technical implementation effects. When comparing the actual effects, the biomass of various plants was converted into that of 1000 m 2 area for comparison.

[0026] Based on their environmental adaptability, the above-mentioned aquatic plants are configured in terms of space and quantity. In the technology demonstration area, due to the change of lake water level, the reed grows in water depths of 40 - 130 cm, the cattail grows in water depths of 45 - 140 cm, the galingale grows in water depths of -10 - 70 cm, the barnyard grass grows in water depths of -10 - 75 cm, the papyrus grows in water depths of -0 - 85 cm, and the hydrilla verticillata grows in water depths of 100 - 190 cm. The proportion of C4 and other aquatic plants in the configuration accounts for 28% of the biomass of all plants, which can effectively compare the carbon sequestration and sink enhancement capabilities of the wetland system. In the control area, due to the change of lake water level, the reed grows in water depths of 45 - 130 cm, the cattail grows in water depths of 50 - 140 cm, the galingale grows in water depths of -15 - 80 cm, the sedge 1 and 2 grow in water depths of -0 - 85 cm, and the vallisneria grows in water depths of 90 - 200 cm. The planting densities in the technology demonstration area and the control area are the same.

[0027] Simultaneously with the above experiment, from March to October 2022, a simulation experiment was carried out on the shore of Chaohu Lake using 63 large plastic barrels with a height of 1.5 m and a diameter of 0.60 m to test the growth conditions of reeds, cattails, galingales, papyrus, barnyard grass, Spartina alterniflora, and sedges under different water depth conditions; at the same time, 9 large plastic barrels with a height of 0.9 m and a diameter of 0.60 m were suspended in the lake at water depths of 0.80 m, 1.60 m, and 2.00 m to test the growth of hydrilla verticillata and vallisneria under various water depth conditions.

[0028] Monitoring of implementation effects: The test results show that the reeds, cattails, galingales, papyrus, barnyard grass, Spartina alterniflora, and sedges grow best and have the highest biomass when growing under water depth conditions of 0.50 m, 0.60 m, 0.30 m, 0.30 m, 0.30 m, 0.50 m, and 0.40 m respectively; the hydrilla verticillata and vallisneria grow best and have the highest biomass when growing under a water depth of 1.60 m.

[0029] From July to October 2022, the growth conditions of aquatic plants in the technology demonstration area and the control area were monitored, and the results are shown in Figures 1 - 3 。 Figure 1 This is the monitoring result of the wetland plant biomass in the technology demonstration area of the technology site from June to October, showing that the C3 plant reed and the C4 plants papyrus and hydrilla verticillata have relatively high biomass. Figure 2 This is the monitoring result of the wetland plant biomass in the control area from June to October, showing that the biomass of the C3 plants sedge 1, sedge 2, and vallisneria is relatively low. Figure 3 This is the comparison of the monitoring results of the wetland plant biomass in the technology demonstration area and the control area from June to October, indicating that from July to October, the total plant biomass in the technology demonstration area is significantly higher than that in the control area, with increases of 39.3%, 53.7%, 59.9%, and 51.4% respectively.

[0030] In addition, based on this study and the results of our previous experiments, the dry matter yield of C4 plants can be 30%-50% higher than that of C3 plants. Therefore, for aquatic plants such as C4 plants, when the spatial and quantitative configuration reaches more than 10%, the constructed system can increase the total biomass by more than 5% to significantly improve the carbon sequestration and sink enhancement ability of the wetland system. Example

[0031] The monitoring results of the indoor simulation experiment system from March to November 2023 showed that for C4 plants, when configured with 70% C4 plants (20% Cyperus papyrus + 20% Echinochloa caudata + 30% Spartina alterniflora) + 30% C3 plant Phragmites australis, compared with the experimental system that only planted Phragmites australis, the total biomass of the plant community increased by 52.5%, and the biomass of Phragmites australis increased by 10.6%. When configured with 60% C4 plants (20% Cyperus papyrus + 20% Echinochloa caudata + 20% Spartina alterniflora) + 40% C3 plant Typha angustifolia, compared with the experimental system that only planted Typha angustifolia, the total biomass of the plant community increased by 33.5%, and the biomass of Typha angustifolia increased by 7.3%. These experimental results show that C4 plants can not only significantly increase the total biomass but also may promote the productivity of C3 plants, producing a synergistic effect. Therefore, based on the above experimental results, the proportion of C4 plants or C4-like plants to be configured during actual operation should be 20%-70%, which can increase the total biomass of the plant community by about 11%-50% to effectively improve the carbon sequestration and sink enhancement ability of the wetland system.

[0032] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for constructing an aquatic plant community using C4 aquatic plants to enhance carbon sequestration and sink, characterized in that, It includes the following steps: When carrying out the restoration of aquatic vegetation in lakes, in the step of planting aquatic plants, C4 aquatic plants or C4-like aquatic plants are planted synchronously. The C4-like aquatic plants are aquatic plants whose photosynthesis products change into C4 compounds when absorbing and assimilating CO2 in the air.

2. The method according to claim 1, wherein The C4 aquatic plants are one or more of Cyperus papyrus, Echinochloa crusgalli, Echinochloa caudata, or Spartina alterniflora.

3. The method according to claim 2, wherein The C4 aquatic plants are a combination of Cyperus papyrus, Echinochloa caudata, and Spartina alterniflora.

4. The method according to claim 1, wherein The C4-like aquatic plants are Hydrilla verticillata or Ottelia alismoides.

5. The method according to claim 1, wherein The planting proportion of the C4 aquatic plants or C4-like aquatic plants in the planted area accounts for more than 20% of the biomass of all plants.

6. The method according to claim 3 or 5, characterized in that, The planting proportion of the C4 aquatic plants in the planted area accounts for 20% - 70% of the biomass of all plants. Among the C4 aquatic plants, Cyperus papyrus accounts for 5% - 20%, Echinochloa caudata accounts for 5% - 20%, and Spartina alterniflora accounts for 10% - 30% of the biomass.

7. The method according to claim 1, wherein The C4 aquatic plants are planted on the shore or in the shoal where the water depth is below 60 cm.

8. The method according to claim 2 or 7, characterized in that When the C4 aquatic plant is Cyperus papyrus, the planting water depth is below 40 cm; when the C4 aquatic plant is Echinochloa crusgalli or Echinochloa caudata, the planting water depth is below 30 cm; when the C4 aquatic plant is Spartina alterniflora, the planting water depth is below 50 cm.

9. The method according to claim 1, wherein The C4-like aquatic plants are planted in the area where the water depth is 80 - 160 cm.

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