Method for in-situ determination of deep water reservoir sediment denitrification and anaerobic ammonia oxidation rates

[0033] Example

[0034] A method for in-situ determination of the denitrification and anammox rate of sediments in deep water reservoirs, mainly using a sediment in-situ replacement device, such as figure 1 As shown, the schematic diagram of the separation of the culture tube and the culture tube protective cover is as follows figure 2 Shown. A device for changing the original position of sediments, including a wire rope 1, a heavy hammer starter 2, a roller 3, a heavy hammer 4, a rotating cover 5, a support 6, a counterweight 7, a sinker plate 8, a culture tube protective cover 9, and a culture Tube 10, rotating cover pin 11. The bracket 6, the anti-settling plate 8 and the culture tube protective sleeve 9 are welded together to form the main body of the device. The counterweight 7 can be added to the anti-settling plate 8 according to the water depth to ensure good contact between the device and the sediment; the roller 3 is located on the support 6, one end of the roller 3 is connected to the weight 4 by a rope, and the other end is connected to the rotating cover pin 11 is connected; the heavy hammer 4 is connected to the wire rope 1, and the heavy hammer starter 2 is sleeved on the wire rope 1.

[0035] The support 6 and the anti-settling plate 8 of the sediment in-situ replacement device are made of steel plate materials.

[0036] The culture tube 10 is a hollow round tube made of polyethylene material with open ends, with a diameter of 50 mm, a thickness of 2 mm, and a length of 500 mm.

[0037] The culture tube protective sleeve 9 is a hollow steel tube with a diameter of 60 mm, a thickness of 5 mm, and a length of 550 mm.

[0038] The specific method includes the following content: the sample preparation process is: first use a box sampler to collect a low-disturbance sediment sample and overlying water, drain the overlying water from the collection box and store it; then insert the culture tube 10 with two openings into the box for sampling vertically In the sediment in the container, open the valve at the bottom of the box sampler, remove the box sampler, and seal the bottom end of the culture tube 10 with a lid to prepare the sample.

[0039] The steps of using the original position of the sediment to change the device to carry out the experimental test are: the first step is to collect the water overlying the sediment with the water collector; the second step is to put the sample to be reacted into the culture tube 10; the third step is to take Add 20ml of excess sample and mix with the overlying water and fill it into the culture tube protective sleeve 9, then put the prepared culture tube 10 into the culture tube protective sleeve 9, and make sure that the experimental sample fills the culture tube 10 and the culture tube protective sleeve Fill the gap in 9 with the overlying water to the culture tube protective sleeve 9, close the rotating cover 5 and insert the rotating cover latch 11; the fourth step, use an electric winch to slowly put the entire sediment in the original position of the replacement device under the water , Until the anti-settling plate 8 touches the surface of the sediment (subject to the no more force on the wire rope 1), put the heavy hammer starter 2 along the wire rope 1 and open the rotating cover 5; in the fifth step, after reaching the reaction time, The original position of the sediment was replaced by a device to raise the water surface and test related indicators.

[0040] Set up four identical samples at each research point in different areas, and implant them into the sediment according to the operation method of changing the device in the original position of the sediment; after the reaction for 10 days, take out the culture tube 10, and press the sample 1-6cm into 1cm/layer, 6cm -20cm is collected at 2cm/layer, and after 20cm, it is collected at 5cm/layer. Then add the sample into a closed anaerobic sampling bottle purged with helium, and then add the calibrated 15 NO- 2 , Put it in a constant temperature water bath and shake for 40 minutes, then use the raw water to remove the mixed gas after the reaction, and bring it into the laboratory for determination with an isotope mass spectrometer (ThermoFisher DELTA V Advantage, USA) 14 N 15 N and 15 N 15 N content. From product N 2 Look at the isotopic composition of 14 N 14 N, 14 N 15 N and 15 N 15 N will be (1-F) 2 : 2F(1-F): F 2 , Where F is in the culture system 15 The abundance of N. produced 15 N 15 N only comes from the contribution of denitrification, while 14 N 15 N is produced by both denitrification and anammox. Therefore, using the measured 15 N 15 N production can calculate the denitrification rate and denitrification 14 N 15 N, then determined by 14 N 15 Total N production minus denitrification 14 N 15 N production is produced by anammox 14 N 15 N, combined with anammox reaction 14 N 14 N: 14 N 15 N production ratio (1-F): F, the anammox rate can be calculated.