Coastal ecosystem health status and ecological monitoring area
Provided by National Marine Environmental Monitoring Center
The ecosystem of Shuangtaizi estuary ecological monitoring area is in sub-health state. Eutrophication of water body; The dissolved oxygen content is low, with 93% of the waters exceeding the first-class water quality standard in May and 80% exceeding the second-class water quality standard in August. There is a certain degree of oil pollution in the sea area near the oil platform; In May, the average salinity in the coastal waters of the estuary was 33.32, which was close to the highest level in history. Other environmental indicators remained basically good. The structure of biological community has changed, and the density of phytoplankton and the biomass of zooplankton have increased. In August, the average density of phytoplankton was 9.4× 105 /m3, and the average biomass of zooplankton was 985.5 mg/m3. The species composition of benthic organisms is mainly polychaete and small shellfish, and the habitat density increases and the biomass decreases. The spawning ground in the estuary has deteriorated, and in recent years, the species of fish eggs and larvae are few and the density is low. The loss and destruction of reed wetland habitat is serious, which is reduced by more than 60% compared with 1987.
Marine development activities such as oil field development, pond culture, rice field reclamation and overfishing, and land-based sewage discharge in the monitoring area are the main factors threatening the health of Shuangtaizi estuary ecosystem.
The ecosystem of Luanhekou-Beidaihe ecological monitoring area is in a sub-health state. The seawater quality and sediment quality are in good condition. The habitat density and biomass of benthic organisms showed a downward trend. In August, the average habitat density was 2 12 individuals /m2, and the average biomass was 17g/m2. The coastal erosion is serious, and the coastal section with serious erosion in the monitoring area is 64 kilometers, accounting for 50% of the total coastal section. The decrease of sediment discharge in estuaries led to the change of benthic sedimentary environment, and the sediment concentration in sediments decreased from 82% in 2000 to 74% in 2004. Due to the degradation of medium-fine sand and fine-medium sandy sediments suitable for amphioxus to live in Luanhe estuary, the population of amphioxus, a national second-class protected animal, decreased by 63% compared with 1999.
The main factors affecting the health of Luanhe-Beidaihe ecosystem are the reduction of fresh water sediment transport, the excessive density of mariculture, port shipping and land-based sewage discharge.
The ecosystem in Bohai Bay ecological monitoring area is in sub-health state. Inorganic nitrogen and active phosphate in this sea area are seriously polluted. The sea areas of Grade IV and Super IV seawater quality are 40% and 20% respectively. The water body is eutrophic, and the proportion of nutrients is unbalanced. The phytoplankton density increased, and the average phytoplankton density in June was 1.3× 106 /m3. The species composition of zooplankton has changed, and the proportion of Hucho taimen, an important bait of marine fish, in zooplankton has decreased. The dominant species of zooplankton in June and August are Archean strongman, magnetic crab flea larva, long-tailed larva and short-tailed flea larva. Philosophy has become the dominant species. The spawning grounds are degraded, and the species of fish eggs and larvae are few and the density is low, with an average of 2 fish eggs and larvae per cubic meter. Marine fishery resources have dropped significantly. For example, the annual catch in Tanggu District dropped from 40,000-50,000 tons in the late 1980s to1.3,000 tons in the last two or three years. Coastal wetlands have been reduced by more than 50%.
Land-based pollution, overfishing and reclamation are the main factors affecting the ecosystem health in Bohai Bay.
The ecosystem of Laizhou Bay ecological monitoring area is in an unhealthy state. More than 80% of inorganic nitrogen in this sea area meets or exceeds the fourth class seawater quality standard, and about 15% of active phosphate in this sea area exceeds the second class seawater quality standard, resulting in serious eutrophication. The ratio of nutrients is seriously out of balance. In August, the ratio of nitrogen and phosphorus was 485: 1, ranging from 2 1: 1 to 2804:1; About 30% of the sea area is polluted by oil, which exceeds the first-class water quality standard; In August, the chemical oxygen consumption in 50% of the sea areas exceeded the second-class seawater quality standard. Phytoplankton density and zooplankton biomass increased. The average density of phytoplankton in August was 1.3× 107 /m3, and the average biomass of zooplankton in May was 433 mg/m3. The benthic biodiversity near the Xiaoqing River estuary at the bottom of Laizhou Bay is poor, and the diversity index is less than 1. The density of Nereis nereis resistant to organic pollution is high, reaching 98 /m2. The spawning ground is seriously degraded, with few species and low density of fish eggs and larvae, with only a few fish eggs and larvae per 100 cubic meter on average. Large-scale reclamation in recent 20 years has seriously shrunk the wetland in Laizhou Bay. More than half of the coastal wetlands have been transformed into artificial wetlands, and 80% of the tidal flat wetlands on the south bank of Laizhou Bay have become salt fields and aquaculture ponds. At the same time, the winding natural coastline has been transformed into a simple and straight coastline by highway around the sea, land reclamation and other projects, and three quarters of the coastline of Laizhou Bay has become a straight artificial coastline.
Land-based pollution discharge, greatly reduced water inflow into the Yellow River, unreasonable aquaculture activities and overfishing are the main factors leading to the unhealthy ecosystem of Laizhou Bay.
The ecosystem in the ecological monitoring area of the Yellow River Estuary is in an unhealthy state. More than 60% of the sea areas meet or exceed the four kinds of seawater quality standards, and the water body is seriously eutrophic, and the proportion of nutrients is seriously unbalanced. The average ratio of nitrogen to phosphorus in August was 482: 1. The phytoplankton density and zooplankton biomass increased, with the average phytoplankton density of 6.6× 106 cells/m3 in August and 1.298 mg/m3 in May. The biomass of benthos decreased, with an average density of 902 in May and an average biomass of 6.3g/m2. The spawning ground is seriously degraded, with few species and low density of fish eggs and larvae, with only a few fish eggs and larvae per 100 cubic meter on average. Coastline is silted and eroded. In recent three years, Xiaoshazui has been silted into the sea for about 3 kilometers, and the land reclamation area is about 12 square kilometers. The top of the original big sand mouth continues to erode by about 1.5km. ..
Land-based pollution discharge, greatly reduced water inflow into the Yellow River and overfishing are the main factors leading to the unhealthy ecosystem of the Yellow River Estuary.
The ecosystem of Subei Shoal Ecological Monitoring Area is in sub-health state. In summer, inorganic nitrogen in all the sea areas exceeded the four-class seawater quality standards, and about 40% of the sea areas reached or exceeded the four-class seawater quality standards, resulting in serious eutrophication. The proportion of nutrients is unbalanced; Tidal flat organisms are polluted by petroleum hydrocarbons and heavy metal cadmium. The benthic biomass decreased obviously. In August, the average habitat density was 0.009 /m2, and the average biomass was 0.02 1g/m2, which decreased by 89% and 78% respectively compared with 1983, and the benthic resources decreased obviously. The average density of fish eggs and larvae increased, with an average of about 17 fish eggs and 1 1 larvae per cubic meter, but the proportion of important economic species decreased. The dominant species of fish eggs were replaced by catfish, and the dominant species of larvae were replaced by anchovies. The area of coastal wetlands has decreased, and in 2004, nearly 1 10,000 hectares of beaches were reclaimed. In the past two years, Meretrix meretrix has died in large areas year after year. Since August this year, there has been a large area of laver death and rotten vegetables in shellfish culture in Nantong and Yancheng waters, and the affected area accounts for more than 20% of the culture area.
Land-based pollution discharge, beach reclamation, overfishing and beach culture are the main factors threatening the health of beach wetland ecosystem in northern Jiangsu.
The ecosystem in the ecological monitoring area of the Yangtze River estuary is in an unhealthy state. The eutrophication of water body is serious; The proportion of nutrients is seriously out of balance. In May and August, the ratios of nitrogen and phosphorus in surface and bottom seawater were 102: 1, 57: 1 and 5 1: 1, 36: 1, respectively. In the eastern waters of the Yangtze River estuary, the dissolved oxygen content in the bottom is very low. In May, the water quality was Grade IV, and the lowest dissolved oxygen content was 3.1mg/L. In August, the bottom dissolved oxygen content was even lower, and the lowest dissolved oxygen content was1.3 mg/L. The species composition of phytoplankton and zooplankton in the Yangtze River estuary changed significantly. In the early 1990s, there were 97 species of phytoplankton, which decreased to about 63 species in the late 1990s. In 2004, the number of phytoplankton species further decreased, reaching 265,438+0 and 42 in May and August respectively, which was more than doubled compared with the early 1990s. In terms of species composition, the number of diatoms decreased, while the proportion of dinoflagellates increased. There were 105 species of zooplankton in the Yangtze estuary in the early 1980s, only 76 species in the early 1990s, which decreased by 28%, and further decreased to about 20 species in the late 1990s, with 25 species and 3 1 species in May and August 2004, respectively, which decreased by about 60% compared with the early 1990s. The biomass of benthos decreased, the community structure of marine organisms tended to be simple, and the biodiversity decreased obviously. In May, 2004, the species number of benthos in the Changjiang Estuary was only about 20% of that in the early 1980s, and the density and biomass were very low, with an average habitat density of 2.5 individuals /m2 and an average biomass of 0.08g/m2. No benthos were collected in 75% of the waters. The spawning grounds are degraded, and the species of fish eggs and larvae are few and the density is low, with an average of 0.5 fish eggs per cubic meter, 1.0 fish larvae. The construction of large-scale water conservancy projects in the Yangtze River basin has led to a decrease in the inflow of fresh water and sediment in the Yangtze River estuary, of which the inflow of fresh water has decreased by more than 20%. With the intensification of seawater intrusion, the volume of the channel below 0 m in the north branch of the Yangtze River estuary has decreased by nearly 60%. The reclamation area of tidal flat is increasing, and the loss of tidal flat wetland resources is serious. Over the past three years, the total reclamation area has been 1 1,000 hectares. From 1 1,989 to now, nearly 40,000 hectares have been reclaimed.
Land-based pollution discharge, estuary waterway regulation, beach reclamation and other development activities are the main factors threatening the health of the Yangtze River estuary ecosystem.
The ecosystem in Hangzhou Bay ecological monitoring area is in an unhealthy state. In spring, the inorganic nitrogen in all sea areas exceeded the fourth class seawater quality standard, and more than 50% of the active phosphate in sea areas reached or exceeded the fourth class seawater quality standard. The water body is seriously eutrophic, and the proportion of nutrients is unbalanced. The density of phytoplankton increased, and the average density of phytoplankton in July was 2.3× 105 cells/m3, which changed the structure of marine biological community. According to years of investigation data, there is only one main benthic community in Hangzhou Bay, represented by white shrimp, which has spiny tail. In 2004, the main benthos evolved into molas, Sigur snails and new worms. The spawning grounds are degraded, and the species of fish eggs and larvae are few and the density is low, with an average of 0.7 fish eggs and 3.0 larvae per cubic meter. Tidal land reclamation and coastal engineering lead to the reduction of wetland area and the loss of benthic habitat. In 2004, the reclamation area around Hangzhou Bay was about 654.38+100000 hectares. In recent ten years, the beach reclamation area on the south bank of Hangzhou Bay is about 200,000 hectares.
Land-based pollution, reclamation, overfishing and a large reduction of water from the Yangtze River are the main factors leading to the unhealthy ecosystem of Hangzhou Bay.
The ecosystem in the ecological monitoring area of Yueqing Bay is in a sub-health state. In spring, the inorganic nitrogen in each sea area exceeds the four kinds of seawater quality standards, and more than 90% of the active phosphate in the sea area meets or exceeds the four kinds of seawater quality standards. The proportion of nutrients is unbalanced, and the water body is seriously eutrophic. The density of phytoplankton increased, and the average density of phytoplankton in August was 3.0× 106 cells/m3, which changed the community structure of marine life. In the early 1980s, the dominant species of benthos in Yueqing Bay were Nereis bifocalis, tumbler, red tooth dragon, odontosaurus, odontosaurus microphylla and China. Reclamation around the sea makes the coast gradually flat, the tortuosity becomes smaller, the flow field changes, the hydrodynamic force weakens, the seawater exchange capacity decreases, and the environmental capacity decreases; The sediment carrying capacity of current decreases, the sedimentation rate in the bay increases, the sedimentation in the bay is serious, and the sedimentary environment changes.
Reclamation, land-based pollution discharge and mariculture are the main factors threatening the ecosystem health of Yueqing Bay.
The ecosystem in the coastal ecological monitoring area in eastern Fujian is in a sub-health state. In spring, more than 30% of inorganic nitrogen in the sea area exceeds the third seawater quality standard, and more than 50% of active phosphate in the sea area exceeds the second seawater quality standard. The proportion of nutrients is unbalanced and the water body is eutrophic. The sediments are polluted by organic matter to a certain extent. From March 2003 to April 2004, seagulls, egrets with yellow mouths, storks, black-winged kites, goshawks, kestrels, long-eared owls, short-eared owls, grasshoppers and nightingales were found in the East Lake wetland and its surrounding areas. The phytoplankton community structure changed in spring. Compared with 1990~ 199 1 year, dinoflagellate, a red tide organism, has become the second dominant species of phytoplankton community. Large-scale reclamation has led to the continuous reduction of beach wetland area in Sanduwan. Since the founding of New China, more than 100 has been reclaimed, with a total area of 1. 1.0000 hectares. Reclamation has led to the degradation of ecological environment, the habitat area of important economic fish, shrimp, crab and shellfish has decreased sharply, and the survival of rare species and the migration of migratory birds have been threatened. Due to overfishing, the fishery resources in the monitoring area have declined, and the fishing season of large yellow croaker has not yet formed, and the spawning ground of large yellow croaker in Guanjing has basically disappeared. The exotic species Spartina alterniflora has occupied 654.38+0.00000 hectares of tidal flat, which seriously threatens the survival of other marine life.
Reclamation, land-based pollution discharge, mariculture, overfishing and alien species invasion are the main factors threatening the health of coastal ecosystems in eastern Fujian.
The ecosystem in Daya Bay ecological monitoring area is in sub-health state. The water quality of Daya Bay is good, and the quality of marine life and sediments is generally good. Mangrove habitat has been seriously lost. From 1986 to 1994, the mangrove habitat decreased from 84 hectares to 4 hectares. After 1999, it was basically stable and the habitat area remained at about 3.6 hectares. Marine development activities such as port construction and mariculture have led to the destruction of intertidal habitats to a certain extent, serious loss of tidal flat wetland habitats and obvious changes in coastline. With the decrease of fishery resources, the function of spawning grounds declines, and some sea areas are affected by thermal pollution.
Reclamation, mariculture, port construction and unreasonable development activities are the main factors threatening the marine ecological health of Daya Bay. With the rapid development of coastal petrochemical industry, chemical pollution such as oil will pose a potential threat to the health of Daya Bay ecosystem.
The ecosystem in the ecological monitoring area of the Pearl River Estuary is in an unhealthy state. In spring, more than 95% of inorganic nitrogen in the sea area exceeds the fourth seawater quality standard, and more than 50% of active phosphate in the sea area meets or exceeds the fourth seawater quality standard. The proportion of nutrients is seriously unbalanced, and the water body is seriously eutrophic. Tidal flat organisms are polluted by heavy metals such as copper, lead, cadmium, zinc and petroleum hydrocarbons. The biomass of benthic organisms is low, with an average biomass of 17.2g/m2 in July, and the species composition tends to be miniaturized. The number of fish eggs is small, with only 5 species in July. The intertidal habitat of the whole Pearl River Estuary has been devastated. Since 1988, the water area of Lingdingyang has decreased by more than 200 square kilometers, and the wetland function has been seriously lost. Since 1995, the reclamation area in Shenzhen Baoan coastal waters has been expanding continuously, and by 2004, the geological features of the original coastal zone have changed significantly. Illegal sand mining has also led to changes in hydrodynamic conditions in some sea areas and increased coastal erosion. Sea level rise threatens the ecological health of tidal flat wetlands in the Pearl River Estuary.
Reclamation, land-based pollution discharge and unreasonable mariculture are the main factors that cause the decline of ecosystem health in the Pearl River Estuary.
The ecosystem in the ecological monitoring area on the southwest coast of Leizhou Peninsula is in a healthy state. The overall environmental quality of the monitoring area is good; Feed organisms are rich in species and high in biomass; The amount of swimming biological resources remained at a high level, with a resource of 707kg/km2 and a density of 104942 fish /km2. The main fishery resources are shrimp, fish and cephalopod, with the resources of 329kg/km2, 308kg/km2 and 28kg/km2 respectively, and the resource structure tends to be normal. There are many kinds of coral reefs, and there have been no deaths in recent years. Sporadic corals have also been added to the monitoring area. However, in some areas, the content of suspended solids in the water is high, reaching 45.3 mg/L. At the same time, it is observed that some coral reefs are covered by a large number of sediments and some corals are bleached.
With the change of fishery development activities from fishing to aquaculture in the monitoring area, the health of the ecosystem along the southwest coast of Leizhou Peninsula is potentially threatened.
The ecosystem of Guangxi Beihai Ecological Monitoring Area is in a healthy state. The overall environmental quality of the monitoring area is good. The density of adult mangrove plants is 6.9 plants/10m2, the average DBH is 7.7cm, and the average density of seedlings is 8. 1 plant/10m2. The growth and reproduction of mangroves are normal. The species diversity of benthic organisms in forest areas is rich; Mangrove habitats have recovered rapidly, and the area of trees has increased by 10% in recent years. The average coverage rate of live corals in Weizhou Island is 20.4%, and the density of coral reef fish such as butterfly fish, rat spot and grouper is relatively high, with a total average density of 34/100 square meter. In recent years, there have been no coral diseases and deaths. At present, six seaweed pastures have been discovered, with a total area of about 400 hectares, mainly distributed in Yingluo Port and Shatian Generation; The average density and biomass of seaweed in Guanwei and Yingluogang monitoring areas of Shaxia, Zhou Dian are 25 plants /m2 and 8.4 g /m2, respectively, and the main distribution species are dictyophora and halophytes. The distribution area and species composition of seagrass beds tend to be stable, and there is no serious degradation and destruction. Man-made development activities such as Weizhou Island port construction affect the coral reef ecosystem in the surrounding waters; The propagation and diffusion of Spartina alterniflora have threatened the growth and survival of mangroves. Mangrove plant Avicennia marina has a large area of pests.
Land-based pollution, unreasonable engineering development and breeding activities and the introduction of exotic species threaten the health of Beihai ecosystem in Guangxi.
The ecosystem of Hainan East Coast Ecological Monitoring Area is in a healthy state. The water quality of most sea areas in the monitoring area is in good condition. The seaweed bed ecosystem is relatively stable, and the coverage and planting density of seaweed in Li 'an, Xincun Port and Gaolongwan all remain at a high level. Among them, the average coverage rate of algae in Yao Di in Li 'an sea area is 97%, and the average coverage rate of Thalassia in Xincun Port and Gaolongwan sea area is 73% and 57% respectively. In recent years, the coral reef ecosystem on the east coast of Hainan is relatively stable, and coral growth is basically normal, without serious diseases or damage. The average coverage rates of living corals in Wuzhizhou, Yulin Bay and Luhuitou waters are 565, 438+0%, 26% and 20% respectively. Coral recovery is remarkable in most areas, and the maximum number of hard corals is 1/m2. Overfishing has led to a sharp decline in the number of coral fish and economic shrimp, crab and shellfish. Mariculture leads to eutrophication in some sea areas such as Changguigang, and a large number of benthic algae appear. The high content of suspended solids in water and decreased light transmittance have posed a serious threat to the normal growth and reproduction of coral reefs. Pollution near estuaries and sewage outlets is increasing, and coral reefs near Yulin Bay and Sanya River are damaged to some extent.
Land-based pollution, overfishing and unreasonable mariculture activities threaten the health of marine ecosystem on the east coast of Hainan.
Source: People's Network