A method for calibrating a long-term fixed observation belt of coral reef ecology

Abstract

The application discloses a kind of coral reef ecological long-term fixed observation sample band calibration method, belong to marine ecological survey and monitoring technical field.The calibration facility of this method is composed of water surface mark and underwater path marker, underwater path marker adopts two rows of permanent marker piles to form the fixed boundary of rectangular observation sample band, and water surface mark is connected with floating ball by cable through cement base, and is respectively arranged at the two ends of underwater path marker.The layout is first punched into two rows of marker piles to determine sample band path at the bottom of sea according to set interval, then water surface mark is installed at corresponding position outside sample band, and when carrying out survey, yardstick is laid and fixed along marker pile, and after survey operation is finished, all yardsticks are recovered.This method is suitable for quantitative observation and long-term ecological evaluation of coral reef benthic community.The method can control sample band area deviation within reasonable range, and the consistency of multiple batches of survey positions is good, which can guarantee the comparability of historical data.

Description

Technical Field

[0001] This invention relates to the field of marine ecological survey and monitoring technology, specifically to the deployment and calibration technology of long-term fixed observation transects on the seabed. Background Technology

[0002] In the field of coral reef ecological surveys, the transect transect method and the transect transect point method are internationally accepted standardized survey methods. Both methods involve conducting observations by deploying measurement transects on the seabed to quantitatively assess the status of corals and benthic communities. Because transects lack clearly defined width boundaries, the interpretation of the data relies on personnel experience to determine the lateral extent. When surveying benthic groups with low abundance, the calculated data is prone to significant deviations. Upgrading transects to fixed-width transects, clearly defining the survey boundaries, can effectively improve the accuracy of density calculations for low-abundance benthic groups.

[0003] Coral reef areas exhibit strong spatial heterogeneity, with significant differences in ecological conditions even over short distances. Current industry standard survey methods rely solely on satellite positioning to record the endpoints of transects. The deployment process is affected by marine environmental factors such as waves, wind, and currents, inevitably leading to transect offsets between multiple surveys conducted at the same location. These offsets cause data deviations and reduce the comparability of historical data from different periods. Therefore, establishing a long-term, fixed underwater observation transect calibration system is the future direction for long-term coral reef ecological monitoring. Summary of the Invention

[0004] The purpose of this invention is to provide a method for calibrating long-term fixed observation transects of coral reef ecology, which solves the problems of unclear boundaries and easy shifts in the location of multiple surveys, resulting in low accuracy of survey data and insufficient comparability of historical data.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for long-term fixed observation transect calibration of coral reef ecology includes the following steps:

[0007] Underwater path markers consisting of two rows of permanent marker stakes are laid on the seabed in the target sea area to form the boundary of the rectangular observation transect;

[0008] Water surface markers consisting of cement bases, cables, and buoys are installed on the outer sides of both ends of the underwater path markers.

[0009] When conducting ecological surveys, the location of the transect is determined by marking the water surface before entering the water, and the measuring tape is laid and fixed along the underwater path.

[0010] All measuring tapes were collected after the survey was completed.

[0011] In one possible implementation, the step of setting underwater path markers to form the boundary of the rectangular observation transect includes:

[0012] The first measuring tape is laid out along the preset direction and straightened. The tip of the permanent marker stake is driven into the seabed at a set interval along the first measuring tape using a hammer to form the first row of marker stakes.

[0013] Use a square to measure the set width of the sample strip, determine the placement of the second measuring tape, and straighten the second measuring tape.

[0014] Along the second measuring tape, at equal intervals, use a hammer to drive the tips of permanent marker stakes into the seabed, forming a second row of marker stakes, so that the two rows of marker stakes together form the rectangular boundary of the observation transect.

[0015] In one possible implementation, the step of installing the water surface markers includes:

[0016] Place the cement base with the pre-embedded fixing ring at a predetermined distance outside the sample strip;

[0017] Tie one end of a cable, the length of which is determined based on the water depth at the highest tide level, to a fixed ring on the concrete base.

[0018] Tie a buoy to the other end of the cable, so that the buoy floats on the water surface and corresponds to the end of the transect.

[0019] In one possible implementation, the step of launching the transect after determining the location of the transect using water surface markers includes:

[0020] The survey vessel navigates to the target sea area using satellite positioning and confirms the position of the end of the transect using buoys on the water surface;

[0021] Divers entered the water near the buoy at the starting point of the transect and searched for and confirmed the complete transect path along the underwater path markers.

[0022] In one possible implementation, the step of laying and securing the measuring tape along the underwater path markings includes:

[0023] Two measuring tapes are laid on the inside of the two rows of permanent marker posts respectively;

[0024] Pass the measuring tape through the ring at the end of the permanent marker post in sequence to fix the measuring tape in place;

[0025] Straighten the measuring tape to keep its length deviation within the preset range.

[0026] One possible implementation also includes a sample maintenance step:

[0027] When a buoy at one end of the transect is damaged or lost, divers enter the water from the other end of the transect, search along the marker path to the corresponding end, and replace the buoy.

[0028] When permanent marker posts are lost or displaced, the reference position is determined based on the tape measure after the installation is completed, and permanent marker posts are then installed or corrected.

[0029] Compared with existing technologies, the advantages of this invention are as follows: Compared with traditional transect surveys without width, this method forms an underwater path marker by deploying two rows of permanent marker stakes on the seabed, creating a rectangular observation transect with a fixed width, thus clearly defining the boundary of the survey. The permanent marker stakes are fixedly embedded in the seabed, maintaining a stable position over a long period. Each survey uses a measuring tape laid along the marker stakes to determine the transect path, avoiding significant positional shifts between different survey batches and improving the comparability of historical survey data. The clearly defined transect boundary also reduces errors caused by subjective judgment of surveyors, improving the accuracy of calculating the density of low-abundance benthic groups.

[0030] Compared to relying solely on satellite positioning to search for survey transects, this method sets water surface markers at both ends of the transect and uses cement bases and cables to fix buoys at the corresponding water surface positions. Surveyors can quickly confirm the end position of the transect using the buoys and, after launching into the water, can quickly confirm the complete transect path along the marker stakes, shortening the positioning time before the survey and improving the efficiency of the survey operation.

[0031] This method, by controlling the spacing between adjacent marker stakes and using a straightened measuring tape during installation to control length deviations, can keep the area deviation of the transect at a low level, ensuring a stable and controllable survey area. After the survey is completed, all measuring tapes can be retrieved, reducing the number of artificial components left underwater for extended periods and minimizing the disturbance of the marking facilities to the in-situ coral reef ecosystem. The permanent marker stakes are made of corrosion-resistant materials, with a stable cement base structure, resulting in good overall durability and relatively low long-term maintenance costs. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the layout of long-term fixed observation transects for coral reef ecology according to an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of a permanent marker post structure according to an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram illustrating the analysis of the deviation in sample area caused by the deformation of the measuring tape in an embodiment of the present invention.

[0036] Figure 4 This is a comparison diagram of the underwater state of two surveys conducted on a fixed transect in an embodiment of the present invention. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0038] Example:

[0039] It should be noted that the terms "comprising" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0040] A method for long-term fixed observation transect calibration of coral reef ecology includes the following steps:

[0041] Step 1: Deploy underwater path markers consisting of two rows of permanent marker stakes on the seabed of the target sea area to form the boundary of the rectangular observation transect.

[0042] Specifically, underwater path markers can be permanent marker structures laid on the seabed to mark the boundaries of transects, and rectangular observation transects can be defined fixed-range survey areas. For example, a single transect is 50m long and 1m wide; each row has 11 permanent marker stakes, for a total of 22 stakes in two rows; and the interval between adjacent permanent marker stakes is 5m.

[0043] The step of setting underwater path markers to form the boundary of the rectangular observation transect includes:

[0044] The first measuring tape is laid out along the preset direction and straightened. The tip of the permanent marker stake is driven into the seabed at a set interval along the first measuring tape using a hammer to form the first row of marker stakes.

[0045] Use a square to measure the set width of the sample strip, determine the placement of the second measuring tape, and straighten the second measuring tape.

[0046] Along the second measuring tape, at equal intervals, use a hammer to drive the tips of permanent marker stakes into the seabed, forming a second row of marker stakes, so that the two rows of marker stakes together form the rectangular boundary of the observation transect.

[0047] Specifically, the set interval can be a predetermined value for the spacing between adjacent marker stakes; the width of the transect can be the vertical distance between two rows of marker stakes; and the square can be a right-angle measuring tool used to calibrate the vertical distance. For example, the total length of the first measuring tape is 50m; the set interval is 5m, and a total of 11 permanent marker stakes are driven into the first row; the width of the transect is set to 1m, and a right-angle square is used to assist in measuring the vertical distance; the number and interval of the marker stakes in the second row are exactly the same as those in the first row, and the two rows together form a rectangular transect 50m long and 1m wide.

[0048] When setting up underwater path markers, divers first lay out the first measuring tape along the predetermined transect route, straightening it completely to serve as a baseline. Along this baseline, markers are positioned at predetermined intervals, and the tips of permanent marker stakes are driven into the seabed sediment with a hammer to secure them, completing the first row of marker stakes. Then, using a right-angle ruler and the first row of measuring tapes as a reference, the predetermined transect width is measured vertically to determine the location of the second measuring tape, which is then straightened to serve as the second baseline. Permanent marker stakes are driven in at the same intervals along the second measuring tape, forming the second row of marker stakes. The two rows of marker stakes are arranged parallel to each other, together forming a regular rectangular observation transect boundary.

[0049] Step 2: Install surface markers consisting of cement bases, cables, and buoys on the outer sides of both ends of the underwater path marker.

[0050] Specifically, the water surface marker can be a marker device that floats on the water surface for rapid positioning of the transect. For example, each set of water surface markers corresponds to one end of the transect, and two sets of water surface markers are configured for a single transect.

[0051] The steps for installing water surface markers include:

[0052] Place the cement base with the pre-embedded fixing ring at a predetermined distance outside the sample strip;

[0053] Tie one end of a cable, the length of which is determined based on the water depth at the highest tide level, to a fixed ring on the concrete base.

[0054] Tie a buoy to the other end of the cable, so that the buoy floats on the water surface and corresponds to the end of the transect.

[0055] Specifically, the fixing ring can be a metal ring embedded in the cement base for connecting the cable; the preset distance can be a pre-set horizontal distance between the base and the edge of the transect; the highest tide depth can be the seawater depth at the corresponding location during the highest tide in the target sea area. For example, the cement base is 40cm long and wide, and 30cm high; the fixing ring is made of 316 stainless steel; the cable length is 1.2 times the water depth during the highest tide; the buoy diameter is 28cm; and the preset distance is 1m to 2m to avoid interference from the base to the transect survey area.

[0056] When installing surface markers, first place the pre-embedded fixing ring on the concrete base at a predetermined distance outside the end of the transect, anchoring it to the seabed by its own weight. Cut a cable suitable for the water depth and securely tie one end of the cable to the fixing ring on the concrete base to prevent it from slipping off. Tie a buoy to the other end of the cable, adjusting the cable's length to ensure the buoy floats on the surface at high tide and that the cable does not become excessively slack at low tide, preventing the buoy from drifting away. The buoy's projection on the water surface corresponds to the end of the transect, providing a visual positioning mark for surface vessels.

[0057] Step 3: When conducting ecological surveys, after determining the location of the transect by marking the water surface, go into the water, mark and lay the measuring tape along the underwater path, and fix it in place.

[0058] The step of launching the sample strip after determining its location using water surface markers includes:

[0059] The survey vessel navigates to the target sea area using satellite positioning and confirms the position of the end of the transect using buoys on the water surface;

[0060] Divers entered the water near the buoy at the starting point of the transect and searched for and confirmed the complete transect path along the underwater path markers.

[0061] Specifically, satellite positioning can be a marine positioning method based on a satellite navigation system; the end position can be the corresponding water surface position at the beginning and end of the transect; the complete transect path can be the entire transect range enclosed by two rows of marker stakes. For example, the survey vessel is equipped with satellite navigation equipment and first sails to the approximate coordinate area of ​​the target transect; after visually searching for the surface buoys, the beginning and end points of the transect are confirmed; after divers enter the water, they can usually find all the marker stakes and confirm the complete transect path within 5 minutes.

[0062] Before commencing the survey, the research vessel navigated to the target sea area where the target transect was located using a satellite positioning system, searching the sea surface for the corresponding buoys. After locating the first and last buoys, the positions of the two ends of the transect were confirmed, and the vessel anchored near the starting buoy. After preparing for the dive, the divers entered the water near the starting buoy of the transect, descended to the seabed, and searched forward along the permanent marker stakes at the starting point, confirming the arrangement of the two rows of marker stakes in sequence to fully identify the path range of the entire transect.

[0063] The step of laying and fixing the measuring tape along the underwater path marking includes:

[0064] Two measuring tapes are laid on the inside of the two rows of permanent marker posts respectively;

[0065] Pass the measuring tape through the ring at the end of the permanent marker post in sequence to fix the measuring tape in place;

[0066] Straighten the measuring tape to keep its length deviation within the preset range.

[0067] Specifically, the inner side can be the side closest to the center of the transect; the ring can be the ring structure at the top of the permanent marker post; the length deviation can be the ratio of the difference between the actual length of the measuring tape and the theoretical straight-line distance. For example, the measuring tape is made of fiberglass and has a single length greater than 50m; the measuring tape passes through the ring at the top of the marker post to achieve point-by-point positioning; the preset length deviation threshold is 0.2%, and the measuring tape is kept as taut as possible during installation to meet the deviation requirements.

[0068] After confirming the transect path, divers took out two measuring tapes and laid them on the inner side of the two rows of permanent marker stakes near the center of the transect. The measuring tapes were then passed sequentially through the rings at the ends of each corresponding permanent marker stake, using the rings to restrict the lateral position of the tapes and thus fixing them point-by-point. Once all tapes were in place, both ends were tightened to keep them as straight as possible, and the length deviation was checked and controlled within the preset allowable range. The two parallel, straight measuring tapes together clearly defined the two side boundaries of the transect.

[0069] Step 4: Collect all measuring tapes after completing the survey.

[0070] In some embodiments, a sample maintenance step is also included:

[0071] When a buoy at one end of the transect is damaged or lost, divers enter the water from the other end of the transect, search along the marker path to the corresponding end, and replace the buoy.

[0072] When permanent marker posts are lost or displaced, the reference position is determined based on the tape measure after the installation is completed, and permanent marker posts are then installed or corrected.

[0073] Specifically, path searching can be a method of locating the corresponding end along the direction of the marker stakes; the reference position can be a standard used to correct the position of the marker stakes. For example, the loss ratio of buoys and marker stakes is less than 5% during two surveys of a single transect; when a buoy is damaged, it can be searched on foot along the path of the stakes from the opposite end; when a marker stake is displaced, the position is corrected using a straightened measuring tape as a reference, and missing marker stakes are replaced according to the scale of the measuring tape.

[0074] Maintenance work is carried out simultaneously during the use of the transect. If a buoy at one end of the transect is found to be damaged or missing, divers will enter the water from the other intact end of the transect and search forward along the path of the two rows of underwater marker stakes. Upon reaching the target end, a new buoy will be replaced and securely fastened, restoring the surface positioning markers. If a permanent marker stake is found to be missing or misaligned, a measuring tape will be laid and straightened to determine the reference position. Misaligned marker stakes will be corrected back to their original positions using the measuring tape as a reference. Missing marker stakes will be replaced and fixed according to their corresponding scale positions to ensure the long-term stability and repeatability of the transect boundary.

[0075] The following is in conjunction with the appendix Figure 1 To be continued Figure 4 Table 1 provides a detailed description of specific embodiments of the present invention. These embodiments are based on the technical solution of the present invention and provide detailed implementation steps and parameter references; however, the scope of protection of the present invention is not limited to the following embodiments.

[0076] The calibration facility used in the long-term fixed observation transect calibration method for coral reef ecology described in this invention consists of two parts: surface markers and underwater path markers. Each transect includes two sets of surface markers and one set of underwater path markers. The two sets of surface markers are placed at the beginning and end of the underwater path markers, and the overall layout is as follows: Figure 1 As shown.

[0077] The water surface marker consists of three parts: a concrete base 3, a cable 4, and a buoy 5. The concrete base 3 is 40cm long and wide, and 30cm high. A 316 stainless steel fixing ring is embedded inside the base, with a hollow dimension of approximately 10cm. The length of the cable 4 is determined to be 1.2 times the water depth at the highest tide level, and the diameter of the buoy 5 is 28cm.

[0078] The underwater path marker consists of two rows of permanent marker stakes 1 and a recyclable measuring tape 2. Each transect contains 22 permanent marker stakes 1, which are 316 stainless steel nails with a diameter of 2cm. One end is sharpened into a cone shape with a height of 6cm, and the other end is bent into a ring shape with an outer diameter of 4.5cm and a 1cm opening. The specific structure is as follows. Figure 2 As shown. The recyclable measuring tape 2 is made of fiberglass, and each measuring tape 2 is longer than 50m.

[0079] When conducting transect calibration, underwater path markers are first laid out. Personnel lay out the first 50m long measuring tape 2 along the predetermined direction. After straightening the measuring tape 2, permanent marker stakes 1 are fixed at the corresponding positions. Eleven permanent marker stakes 1 are driven into the seabed using a hammer, forming the first row of marker stakes. Then, using a square, 1m intervals are measured to mark the location of the second measuring tape 2. After straightening the second measuring tape 2, another 11 permanent marker stakes 1 are driven in at the same intervals along it, forming the second row of marker stakes. The two rows of permanent marker stakes 1 together enclose a rectangular area 50m long and 1m wide; this area is the calibrated underwater fixed survey transect.

[0080] After the permanent marker stake 1 for underwater path marking is fixed, the surface marking device is installed. The workers place the cement base 3 1 to 2 meters away from the transect, tie one end of the cable 4 to the fixing ring of the cement base 3, and attach the other end to the buoy 5, so that the buoy 5 floats on the water surface to provide positioning marks for the surface operation.

[0081] In the actual deployment process, the length of the measuring tape 2 will be slightly larger than the straight-line distance between the permanent marker stakes 1. The measuring tape 2 will bend under the influence of ocean currents, forming an arc-shaped path that deviates from the original straight-line path. The impact of this deviation on the transect area is as follows: Figure 3 As shown in the figure. The maximum deviation of the sample area can be determined by the ratio of the area of ​​the arc formed by the straight line of permanent marker post 1 and the arc of tape measure 2 to the area of ​​the sample area. Assuming that the deformation elongation ratio of the tape measure 2 is between 0.1% and 1%, the spacing between adjacent marker posts is a, and the width of the sample area is b, the area deviation level of tape measure 2 under different deformation conditions can be calculated. The specific parameter relationships are shown in Table 1.

[0082] Table 1. Deviation level of the sample area under different deformation conditions of the measuring tape path.

[0083] The area deviation rate of the transect is directly proportional to the spacing 'a' between adjacent marker posts, inversely proportional to the transect width 'b', and positively correlated with the deformation rate of the measuring tape. In practice, the deformation ratio of the measuring tape 2 can be controlled by selecting a measuring tape with a lower elastic coefficient and by stretching it as taut as possible during installation. Increasing the transect width 'b' can reduce the area deviation rate, but due to limitations in the shooting angle and resolution of the camera, the maximum transect width cannot exceed 1m. If the area deviation is controlled within 10%, and the deformation rate is 0.20%, combined with the parameter of taking the maximum transect width of 1m, the spacing between adjacent marker posts should not exceed 5.56m. Considering the actual operating scenario, a spacing of 5m is more appropriate.

[0084] During ecological surveys, survey vessels use satellite positioning to reach the target sea area. Using buoys 5 on the water's surface, the specific location of the transect is confirmed. After completing preparatory work, divers enter the water near buoy 5 at the transect's starting point and deploy measuring tapes 2 along the underwater permanent marker stakes 1. During deployment, the measuring tapes 2 are kept as taut as possible, and are secured by passing them sequentially through the rings at the ends of the permanent marker stakes 1, ensuring the length deviation of the measuring tapes 2 is less than 0.2%. After each survey operation, all measuring tapes 2 are immediately retrieved to minimize the disturbance to the ecological environment caused by prolonged underwater exposure.

[0085] During the investigation, maintenance work on the fixed transects was carried out simultaneously. If the buoy 5 at the starting point of the transect was damaged or lost, divers would enter the water from the end point of the transect, search along the permanent marker stake 1 to the starting point, and update or repair the surface marker. If the buoy 5 at the end point of the transect was damaged or lost, it would be replaced and updated in the same manner. If the permanent marker stake 1 was lost or displaced, the workers would determine the reference position by referring to the deployed measuring tape 2, and then replace or correct the permanent marker stake 1.

[0086] In practical application, in April 2025, 12 transects and 36 long-term fixed underwater observation transects of coral reefs were established in the waters of Yongxing Island and Qilianyu Islands in the Xisha Islands of Hainan, forming a long-term fixed underwater observation transect network. Two surveys were conducted using this fixed transect network in April and September of the same year. The underwater transect conditions in the two surveys are as follows: Figure 4 As shown in the diagram. During both surveys, the loss of surface buoys and underwater permanent marker stakes was less than 5%, with no loss of cement bases. Missing buoys and permanent marker stakes were replaced during the second survey. The secondary positioning efficiency of the fixed transects was high; the original paths of all transects were re-established within 5 minutes of the survey personnel entering the water. The results of both surveys show that the fixed transects are accurately positioned and can effectively track and monitor the evolution of coral reef ecosystems.

[0087] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0088] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for calibrating long-term fixed observation transects of coral reef ecology, characterized in that, Includes the following steps: Underwater path markers consisting of two rows of permanent marker stakes are laid on the seabed in the target sea area to form the boundary of the rectangular observation transect; Water surface markers consisting of cement bases, cables, and buoys are installed on the outer sides of both ends of the underwater path markers. When conducting ecological surveys, the location of the transect is determined by marking the water surface before entering the water, and the measuring tape is laid and fixed along the underwater path. All measuring tapes were collected after the survey was completed.

2. The method for calibrating long-term fixed observation transects of coral reef ecology according to claim 1, characterized in that, The step of setting underwater path markers to form the boundary of the rectangular observation transect includes: The first measuring tape is laid out along the preset direction and straightened. The tip of the permanent marker stake is driven into the seabed at a set interval along the first measuring tape using a hammer to form the first row of marker stakes. Use a square to measure the set width of the sample strip, determine the placement of the second measuring tape, and straighten the second measuring tape. Along the second measuring tape, at equal intervals, use a hammer to drive the tips of permanent marker stakes into the seabed, forming a second row of marker stakes, so that the two rows of marker stakes together form the rectangular boundary of the observation transect.

3. The method for calibrating long-term fixed observation transects of coral reef ecology according to claim 1, characterized in that, The steps for installing water surface markers include: Place the cement base with the pre-embedded fixing ring at a predetermined distance outside the sample strip; Tie one end of a cable, the length of which is determined based on the water depth at the highest tide level, to a fixed ring on the concrete base. Tie a buoy to the other end of the cable, so that the buoy floats on the water surface and corresponds to the end of the transect.

4. The method for calibrating long-term fixed observation transects of coral reef ecology according to claim 1, characterized in that, The step of launching the sample strip after determining its location using water surface markers includes: The survey vessel navigates to the target sea area using satellite positioning and confirms the position of the end of the transect using buoys on the water surface; Divers entered the water near the buoy at the starting point of the transect and searched for and confirmed the complete transect path along the underwater path markers.

5. The method for calibrating long-term fixed observation transects of coral reef ecology according to claim 1, characterized in that, The steps of marking and fixing the measuring tape along the underwater path include: Two measuring tapes are laid on the inside of the two rows of permanent marker posts respectively; Pass the measuring tape through the ring at the end of the permanent marker post in sequence to fix the measuring tape in place; Straighten the measuring tape to keep its length deviation within the preset range.

6. The method for calibrating long-term fixed observation transects of coral reef ecology according to claim 1, characterized in that, It also includes sample strip maintenance steps: When a buoy at one end of the transect is damaged or lost, divers enter the water from the other end of the transect, search along the marker path to the corresponding end, and replace the buoy. When permanent marker posts are lost or displaced, the reference position is determined based on the tape measure after the installation is completed, and permanent marker posts are then installed or corrected.

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