When a river salty tide occurs, in addition to causing a shortage of fresh water, it may also cause

A is not the reason: the retreat of coastal erosion is usually due to the effect of sea level rise, storm surge, open sea tidal waves and other hydrodynamic forces acting on the coast, and the salty tide is just the slow development of seawater in the form of salt water wedges towards the estuary, and cannot form erosion dynamics.

b Reasons for incorrect: Near-land subsidence in the coastal zone is caused by over-exploitation of groundwater or subsidence of underground karst tectonics. It has little to do with salty tides.

c. Wrong reason: The main reason for the salinization of the delta land is the long-term invasion of seawater in the form of groundwater, resulting in the increase in soil salinity. Salty tides are caused by the decrease of upstream water that causes the specific gravity of seawater to move up with the process of high tide, which has little to do with long-term seawater intrusion.

Therefore, in addition to the nutrients mentioned in the above two mention, the nutrients are not easy to diffuse in the estuarine area, and the saltwater increases the salt content of the estuary area, which is conducive to the growth and explosion of special algae.

Presumably you should know a few other items, this choice D, I thought about it, the salty tide is coming, so naturally the river flows out to the sea, you think, how much sewage will flow out of the sea area, rich in nutrients The sewage breeds algae, so it will cause red tide!

Because most of the aquatic plants in the water can't survive at this time, which leads to a lack of oxygen in the water, which leads to algae explosions and red tides.

b. This question examines the influence of geostrophic deflection forces. The geostrophic deflection force in the northern hemisphere is to the right, so the water flow in the south port is strong and the water flow in the north port is weak, so the north port is seriously affected by seawater intrusion and the salty tide intrusion is strong. So choose option B for this question.

In the simplest terms, salty tides are seawater inflows.

Salty tides generally occur near the mouth of rivers and are formed when the force of sea water is greater than that of fresh water.

The reasons for this are generally as follows:

1. Astronomical factors. When the tides are stronger, a large amount of seawater rushes to land. Since the estuary of the river is generally a large flare facing the ocean, a large amount of seawater is concentrated in the estuary, which increases the salinity of the water in the estuary.

2. River factors. When there is less water coming from the river, whether due to human or natural causes, the water level in the estuary drops, and seawater rushes to the estuary.

3. Climatic factors. Salty tides generally occur when there is less precipitation. Without the dilution of precipitation, the salinity of the estuary's water rises.

4. Groundwater factors. If groundwater is pumped too much near an estuary, it can lead to a drop in the water table and a backflow of seawater.

Irregular release of water from reservoirs does have an impact on salty tides, but it is not a major one, only an auxiliary factor. The biggest factor is astronomical.

The recent precipitation in the middle and lower reaches of the Yangtze River has been very low, and the impoundment of water in the Three Gorges has exacerbated the salty tide in the lower reaches. Without such a prolonged drought, the salty tide at the mouth of the Yangtze River would normally last only a few days. If the water from the upstream does not increase, there is no telling how serious the situation will be.

Salty tides, which generally occur near estuaries, are mainly due to the lack of precipitation in the river basin and the water level of the estuary falling below sea level, resulting in seawater inundation. In addition, irregular impoundment of water in reservoirs can also be caused.

Reservoir release generally does not, but in the dry season, irregular release of water will not be in the short term, but if the drought persists and the precipitation is insufficient, resulting in the river water not being replenished, it can also cause salty tides.

If this year's drought in the middle and lower reaches of the Yangtze River is not effectively alleviated, there will also be salty tides if the conditions are right. Of course, there will be no salty tide in the Yellow River, and the bottom of the downstream river is several meters above sea level, and even if the flow is cut off, there will be no salty tide.

Salty tide is the phenomenon that the water from the upstream of the river decreases, and the seawater flows back from the estuary of the river to the upstream of the river, that is, the junction of freshwater and seawater was originally at the mouth of the river, but now the freshwater is insufficient, the seawater invades, and the junction line moves inland.

The impact of reservoir release depends on what reservoir and how to release, the reservoir is generally in the upper reaches of the river, if there are large tributaries in the downstream of the river, then the impact of water release is not large, if there is no large tributary or the water volume of the tributaries is insufficient, at this time, if the discharge flow is increased, the junction line extends to the ocean, which will not cause the salt tide, if the discharge flow is reduced, or even not the water is released, then it is very likely to cause the salt tide.

In recent years, the rainfall in the middle and lower reaches of the Yangtze River has been very unstable, and it is generally low.

I know that sand mining causes the river to be lower and has an impact on the salty tides, the tides, the flow of the river.

Salty tide: Under normal circumstances, the river water flows to the ocean, but due to the decrease in the flow of the river, the seawater inflows into the sea, and the seawater flows into the river to become salty, which is called the salty tide. Yes.

The occurrence of a salty tide is an increase in the salinity of the seawater.

The so-called salty tide is, in short, the phenomenon of seawater inflow. It mostly occurs when precipitation decreases sharply, river runoff decreases significantly, and the water level is below sea level. Generally speaking, reservoir water release is one of the measures to prevent and control salty tides, and there are strict regulations on reservoir water release, and there will be no irregular water release.

As for the precipitation in the middle and lower reaches of the Yangtze River in recent years, it is not difficult to speculate that it will change accordingly with the intensification of the global greenhouse effect. Theoretically, it should be reduced.

1) D (2 points) collapsed.

2) Winter and spring (2 points) At this time, the precipitation is less hail and oak is less, and the river water volume is small (2 points); Sea level rise due to global warming (2 points); The low altitude of the Yangtze River Delta is conducive to seawater inflow (2 points) (other answers are reasonable, such as seawater inflow caused by high tide).

3) Pearl River Delta (2 points) next to the source. Outline.

1) According to the use of pH test paper, it can be known that the method of determining the pH of water sample is as follows: put a small piece of pH test paper on the glass plate, and then drop the test solution onto the test paper, and compare the color displayed on the test paper with the standard color card to obtain the pH of the test solution;

2) It can be seen from the chart that the pH of the river water is less than 7 and is acidic, so in order to reduce the pollution of the wastewater of the sulfuric acid plant to the hungry section of the river, it is necessary to choose alkaline substances to neutralize with it, so as to reduce the acidity of the river water, so it is more suitable to choose cheap alkaline calcium hydroxide

3) The extinction of fish and shrimp is due to water pollution, and water pollution is due to the excess of nutrients in the water, resulting in eutrophication of the water body, which makes the aquatic weeds grow wildly, resulting in hypoxia in the water and the death of organisms

4) As can be seen from the table, the amount of dissolved oxygen at A is the largest, indicating that the degree of water pollution is the smallest, so the water should be taken from A.

5) Sulfuric acid reacts with sodium hydroxide to produce sodium sulfate and water, and the equation is: 2NaOH+H2

so4na2

so42h2

o Let the mass of sulfuric acid in this wastewater be x

2naoh+h2

so4na2

so42h2o

4g x 4gxx = so the mass fraction of sulfuric acid in the wastewater is:

So the answer is: rotten reputation.

1) Put a small piece of pH test paper on the glass plate, drop the test solution onto the test paper, and then compare the color displayed on the test paper with the standard color card to obtain the pH of the test solution

2）ca（oh）2

3）n；4）a；

5）2naoh+h2

so4na2

so42h2o；；

1) Salty tide, also known as salt water invasion, is caused by seawater backflow and brackish and fresh water mixing, so the chloride here mainly refers to sodium chloride; To purify the river water, it can be distilled to obtain fresh water;

Therefore, the answer is: NaCl, distilling river water (reasonable answer is acceptable);

2) Sewage filtration can remove broken vegetable leaves, broken plastic film and sediment in the sewage;

So the answer is: filter the sewage;

b) Charcoal has an adsorption effect, which can adsorb the peculiar smell in the water, so the sewage added to charcoal has no odor;

Therefore, the answer is: no, because charcoal has an adsorption effect, which can absorb the odor in the water

1) Salty tide, also known as salt water invasion, is caused by seawater backflow and brackish and fresh water mixing, so the chloride here mainly refers to sodium chloride; To purify the river water, it can be distilled to obtain fresh water;

Therefore, the answer is: NaCl, distilling the river water (reasonable answers are acceptable);

2) Failure to (a) filter the sewage to remove broken vegetable leaves, broken plastic film and sediment from the sewage;

So the answer is: filter the sewage;

b) Charcoal has an adsorption effect, which can adsorb the peculiar smell in the coarse water, so the sewage added to charcoal has no odor;

Therefore, the answer is: no, because charcoal has an adsorption effect, which can absorb the odor in the water

There are three aspects of water pollution: domestic pollution, industrial pollution, and agricultural pollution, according to which you can write a reason, for example: arbitrary discharge of industrial wastewater or pesticides, fertilizers or domestic sewage lost in agriculture;

There are many measures to save water at home, so all water-saving methods are reasonable, such as: washing rice water for watering flowers; change to uninterrupted shower, for intermittent bathing; Use water-saving appliances

Therefore, the answer is: industrial wastewater is discharged arbitrarily and water-saving appliances are used