What causes turbidity in estuaries?
What causes turbidity in estuaries?
Tide-dominated coastal waterways (e.g. deltas, estuaries and tidal creeks) are naturally turbid because strong tidal currents resuspend fine sediment (Figure 1, photo 1 & 2).
What is turbidity maximum zone?
The turbidity maximum zone (TMZ) is the dynamic turbid water area within an estuary where the suspended solid con- centrations, namely, sediment and matter, are consistently and significantly higher than landwards and seawards (Shen, 1995; Gebhardt et al., 2005; Yu et al., 2014; Li et al., 2019).
Do estuaries have high turbidity?
Suspended sediment concentration in the estuarine turbidity maximum. The presence of a turbidity maximum is a common feature of estuaries with substantial tidal motion.
How does turbidity affect estuaries?
Highly turbid water full of suspended material has many effects on the estuarine environment. If an estuary is excessively turbid over long periods, its health and productivity can be greatly diminished. As discussed in Chapter 9, dissolved oxygen is a critical factor controlling biological activity.
What is the turbidity of seawater?
Seawater turbidity is the cloudiness caused by large numbers of individual particles such as very fine clay and minute marine organisms. The measurement of turbidity is a key test of marine water quality. Turbidity in open water may be caused by the growth of phytoplankton and sediment discharge from rivers.
How does salinity change in an estuary?
Salinity levels in estuaries typically decline in the spring when snowmelt and rain increase the freshwater flow from streams and groundwater. Salinity levels usually rise during the summer when higher temperatures increase levels of evaporation in the estuary.
What is the average turbidity of the ocean?
Over several hours suspended sediment concentrations (SSCs) can range from 100–500 mg L-1. Less turbid conditions (10–80 mg L-1) can persist over several days but over longer periods (weeks to months) averages were <10 mg L-1.
What is gravitational circulation?
This allows ‘new’ seawater to enter the estuary via the lower water layers. In this way, a circulation of seawater is created, which is directed inland along the bottom and seaward along the surface, see figure 1. This circulation is called estuarine circulation or gravitational circulation.
How would a large increase in the salinity of an estuary?
How would a large increase in the salinity of an estuary most likely affect the ecosystem of the estuary? All organisms would continue to live as they now do. The number of salt-tolerant organisms would increase, and the number of salt-intolerant organisms would decrease.
What increases salinity in an estuary?
Droughts reduce fresh water input into tidal rivers and bays, which raises salinity in estuaries, and enables salt water to mix farther upstream.
What causes turbidity in ocean?
Highly scattering (turbid) water still reflects much light, while highly absorbing water, such as a blackwater river or lake, is very dark. The scattering particles that cause the water to be turbid can be composed of many things, including sediments and phytoplankton.
What is a high level of turbidity?
High turbidity means that there are a lot of particles suspended in the water and light cannot get through. Low turbidity means that there are fewer particles in the water and it is more clear.