81 results about "Marine ecosystem" patented technology

The invention relates to the technical field of marine organism protection, in particular to a marine organism diversity protection method based on an ecological dynamic model, which comprises the following steps: collecting biological and non-biological data in a marine ecosystem, extracting DNA from a seawater sample by utilizing an environmental DNA technology, and constructing the ecological dynamic model based on the collected ecological data and eDNA analysis result. According to the method, the ecological dynamics model is established, the collected data is stored and verified through the block chain technology, and a marine biological diversity protection scheme is designed and implemented according to the ecological dynamics model prediction result and the block chain verification data. Scientific support is provided for protection decision making, protection measures and management regulations are automatically executed through the intelligent contract technology, the system is allowed to respond immediately when it is detected that key environment variables or biological indexes change, and the flexibility and timeliness of responding to environment changes are greatly improved.

A management system for use in relation to a marine ecosystem includes data collection devices and an agent, such as an autonomous water upwelling or downwelling device, capable of causing implementation of a computer-determined change in the ecosystem, wherein a computer is programmed to operate an intelligent feedback loop and iteratively receive and process gathered data; determining from reinforcement learning whether to implement a change to the ecosystem designed for its improvement, communicate instructions to the agent for implementing the change, observing effects of the change and determining whether a further change would benefit the ecosystem; wherein the change includes causing artificial introduction or removal of water from a depth in the ecosystem by upwelling or downwelling and the rate thereof. Also included is a method of acquiring knowledge of, and managing an ocean ecosystem using the above system.

The invention belongs to the technical field of satellite remote sensing application, and discloses an active and passive satellite remote sensing fused ocean three-dimensional chlorophyll field reconstruction method and system. According to the method, satellite-borne laser radar data is subjected to correction, signal processing and biological optical model inversion, and a chlorophyll a concentration vertical section along an orbit is obtained; forming a training set by the passive satellite observation optical variable and the marine environment variable of which the profile is matched with the space-time, so as to train a long short-term memory (LSTM) neural network model; and utilizing the trained model to reconstruct a three-dimensional chlorophyll a concentration field of a target area according to passive observation and environment variables of the target area. By fusing the advantages of a satellite-borne laser radar ICESat-2 satellite and a passive optical remote sensing satellite, three-dimensional chlorophyll a concentration field detection based on active and passive fusion remote sensing is developed, the structure and function of a marine ecosystem can be deeply known, and three-dimensional dynamic observation of the ocean is realized.

An artificial reef module for marine ecosystem restoration comprises a base having a lattice configuration and one or more poles projecting upwardly from the base and configured to support one or more artificial inhabitation units e.g., made by 3D printing, extrusion, pultrusion, or mold specific clay. The module can be configured with one or more of the artificial inhabitation units mounted on the poles, where each inhabitation unit may comprise a plurality of holes formed therein.

The invention discloses an AdaBoost-based chlorophyll concentration forecasting method and device and a readable medium, and the method comprises the steps: constructing training data, constructing a chlorophyll concentration strong forecasting model integrating a plurality of weak forecasting models, and carrying out the iterative adjustment of the distribution weight of the training data through employing an AdaBoost algorithm in the training process of the weak forecasting models, training each weak forecast model by using the training data used in each iteration to obtain a plurality of trained weak forecast models, and calculating the weight of each trained weak forecast model; inputting the input data into each trained weak forecasting model to obtain a forecasting result of each trained weak forecasting model, and calculating according to the forecasting result of each trained weak forecasting model and the weight of the corresponding trained weak forecasting model to obtain a forecasting result of the chlorophyll concentration strong forecasting model. The method can improve the prediction precision of the near-shore chlorophyll concentration, and provides more accurate and effective prediction support for the protection of a marine ecosystem.

The invention provides a marine ecological evaluation system and method based on big data analysis, and the method comprises the steps: obtaining marine biological diversity data and image data of a marine monitoring region, the marine biological diversity data comprising historical species distribution data and ecological niche indexes; performing streaming processing on the image data by using an edge computing architecture to obtain a biological activity feature map; according to the spatial resolution of the biological activity feature map and historical species distribution data, grid division is performed on the marine monitoring area, a reference species distribution density value of each grid unit is generated, and meanwhile, a species distribution density value of each grid unit is calculated; the negative deviation between the species distribution density value of each grid unit and the corresponding reference species distribution density value is calculated, and when the negative deviation is larger than a preset extinction threshold value, the corresponding grid unit is determined as a species distribution density attenuation area; according to the technical scheme provided by the invention, dynamic evaluation and early warning of the health condition of the marine ecosystem are realized.

The present application relates to the technical field of marine construction engineering, and particularly relates to a modular multi-stage intertidal zone ecological revetment concrete block and a laying method thereof. The ecological revetment concrete block is designed with holes with a diameter of 5 cm-10 cm on the surface, and the hole density is 10-50 per square meter, so that the surface area and the attachment points are increased. The surface concave-convex degree of the ecological revetment concrete block is controlled within a range of plus or minus 5 cm, so that the anti-skid performance is improved, the water flow turbulence is increased, and the oxygen exchange is promoted. By simulating the ecological gradient of the natural intertidal zone, a suitable growth and reproduction environment is provided for marine organisms, and the balance and service function of the marine ecological system are maintained.

The present invention highlights the use of an innovative submersible structure made of concrete enriched with dead algae to promote marine biodiversity. This biodegradable material ensures better integration into aquatic ecosystems while providing a sustainable habitat for marine organisms. Furthermore, the integration of modern technologies such as sensors, sounders, cameras, GPS, modems, and underwater drones is highlighted in both texts. These tools enable real-time monitoring of artificial reefs, ensuring precise tracking of changes in marine habitats and local ecosystems. This monitoring ensures not only effective management of marine ecosystems but also enhanced protection against threats such as coastal erosion. Finally, both sections agree on the environmental and economic benefits of the project. In addition to promoting marine conservation, this invention paves the way for sustainable activities, including ecotourism, while emphasizing ecological sustainability and technological innovation. The project thus illustrates a holistic approach to addressing the environmental challenges linked to the degradation of marine ecosystems. The project represents a significant step forward in the management of marine ecosystems thanks to the combination of modern technological solutions and innovative, eco-friendly materials. By combining biodegradable artificial reefs with advanced monitoring devices, this solution offers an integrated approach to restoring marine biodiversity, protecting coastlines, and promoting sustainable activities. It represents an exemplary model of responsible and technological development, meeting current environmental conservation needs while offering viable economic opportunities.

The present invention relates to an underwater cabled robot, preferably adapted as a cleaning platform, capable of selectively and effectively removing small and large debris from the seabed and from the water column beneath, with minimal impact on the marine ecosystem. The cleaning platform comprises: a floating barge or vessel having an opening providing access to a water column below the floating barge; and a submergible frame fitted with a tool adapted to collect debris underwater. At least three motor-driven winches are attached to the floating barge or vessel, and a system of cables extends through the opening of the floating barge or vessel and connects the winches with the frame. The control unit controls the operation of the capstan in a coordinated manner such that the frame can be moved within the three-dimensional work space under the floating barge or vessel by winding and unwinding the cable to collect debris from the seabed and water column.

The utility model relates to the technical field of oyster reefs, in particular to a multi-stage functional oyster reef. Comprising a corrosion-resistant alloy base and an adsorption mechanism, four conical feet are arranged at the bottom of the corrosion-resistant alloy base, the adsorption mechanism comprises a fixing frame, an adsorption frame, a stabilizing rod, an inclined plate, a top plate and an ecological device, and the adsorption frame is fixed to the fixing frame through corrosion-resistant screws and nuts. The mounting holes in the bottom of the adsorption frame are matched with the adjusting holes in the fixing frame at different positions, different working heights can be directly obtained, further, the corrosion-resistant alloy base is of a solid structure and is more stable compared with a hollow brick structure, the inclined plate and the top plate can be used for assisting oyster attachment, and the service life is prolonged. The ecological device is used for providing diversified biological inhabiting environments, healthy development of a marine ecological system is facilitated, multifunctional use of the oyster reef is achieved, then height adjustment can be achieved during use, multi-environment use of the oyster reef is facilitated, and the practicability of the oyster reef is improved.

The application relates to the technical field of marine ecological monitoring, in particular to a marine ecological dynamic prediction method and system based on multi-modal remote sensing and a space-time graph. The method comprises the following steps: performing multi-modal remote sensing feature depth fusion according to obtained remote sensing image data, wherein the multi-modal remote sensing feature depth fusion comprises multi-modal feature map extraction and space embedding, local cross-modal feature interaction and alignment, and global context aggregation and node embedding generation; constructing a space-time ecological process reasoning network STEP-Net based on coupled space diffusion and time inertia, wherein the space-time ecological process reasoning network STEP-Net comprises multi-order space diffusion field modeling and ecological state transition unit construction; and utilizing deep space-time representation generated by the STEP-Net to perform future-oriented and uncertain trajectory prediction and cause and effect attribution based on deep Taylor decomposition. The application constructs a brand-new technical framework integrating fine fusion, mechanism reasoning and interpretable prediction around the precise prediction and scientific early warning demand of marine ecological system dynamic evolution.

The invention relates to the technical field of marine protection, in particular to rotary marine protection animal selective trawling equipment which comprises a fishing boat and a fixed net fixedly connected to the bottom of the fishing boat, one side of the fixed net is rotationally matched with a rotary net, a discharge outlet is formed in the end, away from the fixed net, of the rotary net, and a fixed ring is fixedly connected to the discharge outlet. An elastic net is fixedly connected into the fixing ring and provided with an adjusting assembly used for adjusting the size of meshes of the elastic net. An intercepting assembly for intercepting large marine organisms is arranged in the fixed net; the method can effectively reduce the false catching rate of the catching operation and reduce the influence of the catching operation on the marine ecology.

The present invention discloses a method for rapid reconstruction of a regional marine environment field based on a ViT neural network, belonging to the field of environmental field reconstruction technology. The method comprises acquiring and preprocessing multi-source marine data, calculating the density field from the preprocessed multi-source marine data, and constructing a multi-factor coupling field based on the temperature field, salinity field, and density field; preparing a deep learning sample set, constructing and training a ViT environmental field generation model, and using the trained ViT environmental field generation model to reconstruct the regional marine environment field. The method comprehensively considers the coupling of multiple marine factor fields and achieves the reconstruction of a three-dimensional environmental field of regional ocean temperature, salinity, and density. The method is accurate, high-resolution, and rapid, and can play a role in data support and application assurance in fields such as marine disaster prevention and mitigation, marine ecosystems, and marine climate change.

To solve problems such as the deterioration of the marine environment, including marine ecosystems, due to marine litter in recent years, particularly the problem of marine plastic litter, which not only occurs in large quantities every day around the world but also remains in the ocean for long periods of time and requires global-scale measures, and problems such as the reuse of industrial waste, such as salmon milt, which amounts to approximately 10,000 tons per year and is disposed of as industrial waste in Japan, in order to realize a sustainable society.SOLUTION: With the aim of potentially reusing the DNA contained in salmon milt and reducing the burden on the marine environment in mind, we focused on DNA not as a gene but as a polymeric material, leading to the invention of a DNA paste that could be used in enzymatically degradable plastics and thin film applications in nanoelectronics. Specifically, dialdehyde is added to an aqueous solution of DNA salt, and the paste is then baked at a temperature above the melting point of DNA, resulting in crosslinking.SELECTED DRAWING: Figure 1

The invention provides a filtering and sampling device for marine environment monitoring, and relates to the technical field of marine environment monitoring, the filtering and sampling device comprises a tank body, a base and a cover plate, one side wall of the tank body is fixedly connected with an adjusting assembly, the interior of the tank body is fixedly connected with a filtering assembly, the base is fixedly connected to the bottom of the tank body, and the cover plate is movably connected to the top of the tank body through a hasp. Through arrangement of the filtering assembly and the adjusting assembly, a servo motor is started, the servo motor drives a rotating rod to rotate through a rotating shaft, and at the moment, the rotating rod drives a fixing frame and a filtering net plate in the fixing frame to filter seawater; the water is discharged into the first multi-way piece through the water outlet pipe arranged at the bottom of the filter box and the connecting branch pipe, and flows into the sampling bottle through the shunting port and the connecting pipeline, so that the device reduces the influence on the nutritive salt circulation mechanism of the whole marine ecosystem, and reduces the possibility that the final analysis result loses accuracy and the sampling time is shortened. And the probability of real evaluation of the marine environment state is influenced.

The invention discloses a marine hormone pollution risk assessment method and system applied to swimming animals, including: water quality sampling and hormone pollution detection, constructing a regional water hormone pollution status map; constructing a pollution change trend prediction model, and predicting the pollution change trend in combination with the regional water hormone pollution status map; analyzing the gathering place preference of swimming organisms in the target marine area, establishing a swimming organism food chain network in the target marine area based on population relationship data, and constructing an ecological simulation model; conducting biological sampling to analyze the biological hormone pollution status in the target marine area, and using the ecological simulation model to analyze the ecological response of the target marine area in the future time period; constructing a risk assessment model, and combining the ecological response analysis information to evaluate the hormone pollution risk of the target marine area in the future time period and provide early warning prompts. Improve the accuracy and comprehensiveness of marine hormone pollution risk assessment and protect the health and sustainability of the marine ecosystem.

The invention relates to an analysis method for branches of a plankton model with an Allee effect of algae, and belongs to the field of prediction and simulation of an algae-zooplankton model in a marine ecosystem. According to the method, the influence of the Alle effect and toxin release of algae is considered, a biological mathematical model about algae-zooplankton is established, and the actual biological significance of the number of model research object populations is determined; sufficient conditions for existence of an internal equilibrium state and local asymptotic stability of the model are given; and taking the growth rate of the algae as a branch parameter, and providing sufficient conditions for the model to generate saddle node branches and transcritical branches. According to the branch analysis method of the algae-zooplankton model based on the Alle effect and toxin release influence of the algae, the periodic evolution law of the population number of the algae and the zooplankton in the aquatic environment can be obtained, and the influence of the growth rate of the algae on the population number is known; and the method has positive guiding significance on the treatment of the marine ecological environment.

This paper provides a method for diagnosing and analyzing air-sea CO2 fluxes using a physical-biological coupled ocean model. This method achieves high-resolution simulation of the marine ecosystem in the China coastal area (118°E-132°E, 24°N-42°N), accurately simulating the basic structural characteristics of the regional ecosystem, particularly the marine carbon cycle. Based on this, a model post-processing method for air-sea CO2 fluxes has been developed. This automated processing of regional high-resolution physical-ecological coupled ocean simulation data includes the preparation of model input data, evaluation of model results, and visualization. The air-sea CO2 flux diagnostic analysis method is improved by incorporating ocean physical process analysis, analyzing the physical processes that cause changes in the air-sea CO2 flux from a holistic perspective.

This invention relates to the field of offshore pile foundation technology and discloses an offshore pile foundation structure, including a pile foundation body, and further comprising: an air source; a control system; a hollow main chamber, vertically arranged inside the pile foundation body, with its top connected to the air source; and high-pressure airbag compensation and stabilization components, with at least two sets of high-pressure airbag compensation and stabilization components distributed along the periphery of the pile foundation body and connected to the hollow main chamber. When the pile foundation body tilts, the air source is controlled by the ground control system to directionally inflate the high-pressure airbag compensation and stabilization components on the side away from the tilt direction, thereby generating a reverse thrust to correct the attitude of the pile foundation body. This method enhances the stability of the pile foundation without increasing the pile diameter or burial depth, reduces the construction cost of offshore pile foundations, and does not cause additional damage to the marine ecosystem.

This invention belongs to the field of coastal ecological restoration and marine aquaculture technology. Specifically, it is an artificial composite reef structure, including a base. The base is a trapezoidal frame structure with multiple frame columns inside. The base columns are fixedly connected to the surface of the base, and the base columns are fixedly connected to the sleeves. The sleeves are slidably connected to the telescopic columns, and the telescopic columns are threadedly connected to the surface of the telescopic columns. The other end of the telescopic columns passes through the sleeves and the base columns, making a slidable connection. By combining the frame-type base with upwelling reefs and bird-standing stakes, a two- or three-layer artificial composite reef structure is formed, creating a multifunctional marine biological reef environment. This overcomes the problems of the single function and limited environment of ordinary biological reefs. It not only has a wider range of applicability, but also organically combines the two- or three-layer structure to create a multifunctional marine habitat, forming a three-in-one marine ecosystem integrating sea, land, and air.

The present invention belongs to the technical field of marine ecosystem research, and relates to a method for evaluating and optimizing the food web of a marine ecosystem. The method for evaluating the food web system of the ecosystem includes the following steps: S1, constructing an energy flow model of the food web of the marine ecosystem; S2, based on the above-established food web energy flow model, obtaining the energy flow relationship between each biological functional group, and quantifying the nutritional relationship and energy flow relationship between each organism in the marine ecosystem; for the target marine ecosystem, selecting other marine ecosystems with similar characteristics to the target marine ecosystem as controls, establishing a control marine ecosystem food web parameter database, and comparing it with the indicators of the control marine ecosystem food web structure and function evaluation to determine the level of the target marine ecosystem food web structure and function. The present invention has formulated a set of more scientific food web structure optimization paths to provide guidance for the development of food web optimization work.

To provide a nutrient supply management system capable of maximizing the amount of carbon dioxide absorbed and stored in the atmosphere by both blue and green carbon.SOLUTION: The nutrient supply management system includes an arithmetic unit that executes calculations related to nutrient salt supply management for marine and terrestrial ecosystems. The arithmetic unit includes a supplyable nutrient salt amount estimation unit that calculates the amount of supplyable nutrient salt based on the emissions of nutrient salts from point and non-point sources in the target area. The arithmetic unit also includes a decarbonization promotion effect evaluation unit that evaluates the effect of marine and terrestrial ecosystems on the supply of nutrient salts. The arithmetic unit also includes a nutrient salt proper distribution unit that sets allocations of nutrient salt supply to marine and terrestrial ecosystems based on the effect of promoting decarbonization.SELECTED DRAWING: Figure 1

The present application relates to the field of environmental monitoring, and more particularly to a marine ecological environment multi-source monitoring and early warning method based on digital twinning, comprising the following steps: forming a mapping of physical sensing devices, virtual twin nodes and spatial grid units; predicting the evolution results of the phase field at multiple future time steps to obtain a key element prediction dataset; performing cluster-by-cluster simulation through clustering of the obtained ecological anomaly event cluster set and all anomaly feature lists included in each event cluster, and completing monitoring and early warning according to the simulation results. The present application defines biological elements and non-biological elements in the marine ecological system as phase field variables in a unified grid-by-grid manner, and introduces an influence term of biological activity into the source-sink term of non-biological phase field variables, thereby achieving deep two-way coupling of biological processes and environmental processes. A prediction control objective function is referenced to real-time monitoring data, and the key parameters of the phase field evolution model are dynamically adjusted by minimizing the mean square error between the predicted value and the real-time monitoring value.

This application relates to the field of marine ecological technologies, particularly to a construction method of marine ecological multi-agents and its interaction system. Among them, the construction method includes: a step of constructing a marine ecological large model, constructing a fine-tuning data set, and training a marine ecological large model based on the fine-tuning data set; a step of constructing a parallel application module, constructing a domain knowledge base, marine ecological multi-agents, and building a multi-modal large model, deploying the domain knowledge base, marine ecological multi-agents, multi-modal large model of the parallel application module and the marine ecological large model on a GPU server, where the marine ecological large model is used to parse user requests and distribute them to the parallel application module, triggering the parallel application module to generate response results and feedback them to the marine ecological large model for semantic integration and then output. Through this application, the intelligent level in the field of marine ecology is improved, the prediction ability of the model is enhanced, and the prediction results are made more accurate and reliable.

The present invention discloses a three-dimensional monitoring device for artificial reefs, which relates to the field of marine ecosystems. The device comprises a protective cover and a suspension assembly. Multiple suspension assemblies are arranged around the outer side of the lower layer of the protective cover. The protective cover comprises an outer shell and an inner shell, both of which are made of transparent materials. Multiple sealing assemblies are provided between the outer and inner shells. A breeding net surrounds the bottom of the inner shell, and a monitoring device is installed on the bottom of the inner shell. The present invention aims to provide a three-dimensional monitoring device for artificial reefs that has a good clustering effect, facilitates observation, and protects the living environment.

The present invention relates to the field of warm wastewater discharge from power plants, and in particular to a device and method for discharging warm wastewater from power plants, the device comprising a drain pipe and a top pipe, the drain pipe being arranged horizontally, the top pipe being arranged at the upper end of the drain pipe, the top pipe being connected to the ocean, and the warm wastewater flowing into the ocean through the drain pipe and the top pipe; the top pipe being a double-layer cylindrical structure, a plurality of blades being arranged between the inner wall of the top pipe and the outer wall of the top pipe, corresponding guide holes being arranged on the inner wall of the top pipe and the top pipe between the two blades, respectively, and the warm wastewater entering the ocean through the guide holes. The present invention enhances the heat dissipation capacity of the warm wastewater by arranging arc-shaped blades and baffles, thereby achieving control over the influence range of the warm wastewater. Compared with the prior art, the drainage system of the present invention can effectively reduce the heat-affected area of ​​the marine environment around the power plant and protect the health of the marine ecosystem.

The application discloses an assembled tower type artificial fish reef and belongs to the technical field of artificial fish reefs. The assembled tower type artificial fish reef comprises a base, a cylindrical side plate fixed to the top surface of the base, a support column, the bottom end of the support column being detachably connected to the center of the base, the top surface being higher than the top surface of the cylindrical side plate, a plurality of support arms being fixed to the outside of the support column and the cylindrical side plate in a radial and circumferential manner, the plurality of support arms being arranged in a staggered manner, the end of each support arm being fixedly connected to a mounting ring, a transplant cup being detachably connected to the mounting ring, and a top plate being detachably connected to the top end of the support column. The application has good space utilization, provides space for the growth and reproduction of corals, can provide larger hiding space for fish, realizes the aggregation of fish, and thus enhances the diversity and productivity of the marine ecosystem. Moreover, the detachable structure of the assembled type is convenient for installation and disassembly, can be adjusted in height according to needs, and has better adaptability.

The present invention provides a multi-level trophic level marine ecosystem simulation device and simulation method, which belongs to the field of marine ecological simulation technology. The device can simulate different marine environments such as coastal, shallow sea, lagoon, hydrothermal vent, etc. by controlling equipment parameters. The method simulates the multi-level biological nutritional structure in different ecosystems by configuring the biological species and quantity of different producers, consumers and decomposers, and combines the environment and organisms to simulate the ecosystem, restore the actual situation in the field to the greatest extent, and realize comprehensive simulation of the ecosystem; at the same time, the cooperation of various devices such as water replenishment, temperature control, circulation, light control, and monitoring can maintain the stability of the ecosystem for a long time, providing stable simulation experimental conditions for quantitative research on marine ecology such as the interaction between organisms and the environment, and also providing experimental method support for achieving carbon neutrality and biodiversity protection.

The present invention discloses a deep-sea mining head that uses vortex shedding to create an upwelling field. The head comprises a mining hood, a front deflector, a rear deflector, a curvature plate, a jet device, and a vortex generating mechanism. The mining hood is a shell with an open bottom, and the front and rear deflectors are positioned relative to each other on the front and rear sides of the hood. The curvature plate is mounted on the top wall of the mining hood and cooperates with the front and rear deflectors to form a flushing and mining chamber. A water supply chamber is formed between the front deflector and the mining hood, and the water supply chamber communicates with the flushing and mining chamber. A suction pipe is positioned above and behind the mining hood, and the vortex generating mechanism comprises a plurality of piles arranged in a transversely spaced sequence. The jet device comprises a water supply pipe assembly, an angle adjustment mechanism, and two sets of jet nozzles, one mounted on the front deflector and the other on the rear deflector. The present invention uses jets to flush seabed mineral nodules, exfoliating them and carrying them backward, making them easier to remove and lift, thereby improving mining efficiency and reducing interference with the marine ecosystem.

The present invention provides a method for estimating the productivity of global land and sea ecosystems based on SIF and light response, including: Step 1, fusing satellite remote sensing image data and meteorological data and performing consistency verification; Step 2, at each pixel point, substituting the input remote sensing data into the mechanical light response (MLR) theoretical formula to estimate the gross primary productivity (GPP), calculating the carbon dioxide partial pressure in the chloroplast stroma, the carbon dioxide compensation point of the chloroplast, the open ratio of the reaction center of the photosynthetic system, the energy ratio of plant heat dissipation and plant-emitted fluorescence, and the escape rate; Step 3, obtaining the distributions of C3 plants and C4 plants using vegetation type distribution data; calculating the gross primary productivity of C3 plants and C4 plants respectively. This solution simplifies the required quantity of vegetation parameters during the inversion process, greatly reduces the difficulty of parameter acquisition while ensuring the inversion accuracy, and at the same time significantly reduces the result uncertainty caused by parameters.