In situ monitoring of water buoy primary productivity
Key words: waste gas
In situ monitoring of water buoy primary productivity
Background and significance of project approval
Primary productivity (GPP) refers to the total amount of fixed organic matter produced by phytoplankton in unit time and unit volume through photosynthesis, which is the basis of carbon cycle in global ecosystem. Quantitative assessment of the primary productivity of Marine phytoplankton is an important link in the study of Marine ecosystem.
Marine carbon sinks play a fundamental role in global climate change and carbon cycle. Has more than 300 square kilometers sea in our country, but our country Marine has how much carbon sinks function, it is lack of scientific and complete observation data, there is no clear conclusion, ecological environment is to organize the implementation of China's ocean carbon sink monitoring and evaluation of carbon flux in the coastal zones, to explore to improve climate resilience and enhance blue carbon sinks increment as the guidance of the protection and restoration of the Marine ecological new pattern. Phytoplankton is the fundamental link of the material cycle and energy flow of the Marine ecosystem. Although the biomass is less than 1% of the global total plant biomass, its primary productivity accounts for more than 45% of the global total primary productivity, and its photosynthetic carbon sequestration accounts for 40% of the global total carbon sequestration. It is the most important biological carbon sink in the ocean. Therefore, rapid monitoring of Marine phytoplankton biomass and primary productivity is of great scientific significance and application value for Marine carbon sink monitoring and coastal carbon flux assessment.
Water primary productivity measurement methods include black and white bottle method, 14C tracer method, 18O tracer method, chlorophyll fluorescence method and so on. Among them, black and white bottle method, 18 o 14 c tracer method, the traditional gas such as tracer method exchange method need "field sampling - offline incubate", sampling process cycle is long, cumbersome procedures, measuring poor timeliness, and also brings in the process of sample training error can not be ignored, to obtain rapid, real-time, accurately primary productivity of water body information, It is difficult to meet the requirements of modern surface water ecology and environment observation.
Independently developed by Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, our company completed the industrialization of the water primary productivity in-situ monitoring instrument, which uses chlorophyll fluorescence as the probe for the energy flow process of algae primary production, breaking through the limitation of the traditional measurement method of "on-site sampling, temperature cultivation and off-line measurement" of black and white bottle and isotope tracer. Shortening the measurement period of primary productivity from 24 hours to 5 minutes is an advanced method for rapid in-situ observation of water primary productivity. Instrument An in situ monitoring device for measuring photosynthetic electron transport rates during primary production of algae using a variable light pulse-induced chlorophyll fluorescence kinetics technique. By blocking the electron transport chain in the photosynthesis process with strong light pulse, the dynamic change process of chlorophyll fluorescence was tracked, and the photosynthetic electron transport rate in the primary production process of algae was obtained by combining the "bio-optics" model, so as to realize the in-situ rapid measurement of primary productivity. The instrument participated in the 10th scientific expedition to the islands and reefs of the South China Sea, the Yellow Sea and Bohai Sea, and the Arctic, and obtained the spatial distribution information of the primary productivity in the surrounding waters and the middle and high latitudes of the world, and accumulated important scientific observation data for the investigation and research of the Marine ecological environment.
The monitoring system is composed of monitoring center, transmission unit, intelligent buoy body, etc., which has functions of system operation status monitoring, video monitoring, primary productivity in-situ monitoring instrument, buoy status monitoring, remote control, remote operation and so on.
The monitoring point takes the buoy body as the platform, and the monitoring equipment can be extended to move vertically through the automatic lifting system in addition to the surface fixed point, so as to realize the stratified data collection. The intelligent buoy body is integrated with the solar power supply system and the wireless acquisition and transmission system, which can automatically report the monitoring data to the data management center station through the GPRS/4G/5G/ Beidou satellite network. At the same time, it is equipped with the safety protection system and operation monitoring and self-check system to effectively ensure the stable operation of the monitoring point in the long-term unattended state.
The buoy-type primary productivity monitoring instrument overcomes the shortcomings of conventional measurement methods, and can provide accurate and rapid monitoring data in real time, continuously, stably and reliably by using wireless data transmission equipment. It is the first in-situ monitoring instrument for water primary productivity based on fluorescence dynamic method in China. The instrument has the characteristics of fast measurement, sensitivity, no sampling culture, no reagent and so on. The measurement cycle of primary productivity is shortened from 24 hours by traditional method to 5 minutes. It provides advanced tools for rapid in-situ observation of primary productivity in the fields of Marine carbon sink and ecological environment observation, Marine red tide disaster monitoring and early warning, fishery resource assessment, Marine geochemical process effect study, global carbon cycle and climate change prediction, and has great development potential and broad application prospect.
Main application fields
In-situ monitoring of primary productivity of surface water in oceans, lakes, reservoirs and rivers.
Monitoring principle and main technical indicators
The in situ monitor of water primary productivity is an on-line monitoring device which uses variable light pulse induced chlorophyll fluorescence dynamics (TPLIF) technology to measure the photosynthetic electron transfer rate during the primary production of algae. Using chlorophyll fluorescence as the probe of the primary production energy flow process of algae, the key technologies such as precise regulation of multi-wavelength variable light pulse adaptive excitation during photosynthetic electron transport and fast and relaxation two-channel fluorescence dynamics fast and highly sensitive detection technology have been broken through. Based on snapshot and relaxation are studied fluorescence kinetics curve of photosynthesis fluorescence parameters inversion algorithm, water, primary productivity fluorescence kinetics measurement model, solved the algae concentration of photosynthetic reaction center, photosynthesis rate details primary production process parameters, such as the accuracy of the measurement problem, using the light pulse blocking photosynthetic electron transport chain, To track changes in chlorophyll fluorescence kinetics process, combined with "biological - optical" model, primary production process for algae photosynthetic electron transport rate, for the accurate measurement of the primary production of phytoplankton provides a means of rapid measurement in situ, in the study of Marine carbon cycle evolution law, prevention and control of climate change and greenhouse effect and so on has important scientific significance and application value.
Main technical performance indexes
Measuring range: 0-1000nmol(e)/(m3·s);
Detection limit: 1nmol(e)/(m3·s);
Measuring accuracy: ≤5%;
Measured water depth: 50m;
Response time: 5min;
Appearance volume: diameter 100mm, length 490mm;
Average power consumption: 35W.