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Thursday, September 10, 2009


The Mastacembelidae are a family of fishes, known as the spiny eels. The Mastacembelids are part of the Order Synbranchiformes, the swamp eels, which are part of the Actinopterygii (ray-finned fishes).

In an evaluation of the family in 2004, the subfamilies of Mastacembelidae were found to not be well supported and were rejected. Also, the genera Caecomastacembelus and Aethiomastacembelus were placed in synonymy with Mastacembelus.

These fish originate from Africa, Southeast Asia, and South Asia.[1] Spiny eels generally inhabit soft-bottomed habitats in fresh and brackish water. Some species burrow in the substrate during the day or for certain months and have been found buried in soil in drying periods.

These fish have an eel-like body. Some of these fish can reach a maximum length of about 1 metre (40 in). Very characteristic of this group is the long nose appendage with two tubulated nostrils.[1] Mastacembelids have a series of well-separated dorsal spines on their back, hence the name of their family, spiny eels.

In some areas these fish are regarded as food fish. Several species of Mastacembelidae are aquarium fish, such as the fire eel Read more.......

Wednesday, July 2, 2008

What is pH?

pH is the measurement of acidity and alkalinity of water bodies with accordance to the concentration of hydrogen ions that are present in the water. pH values lower than 7 is indicated as acidic while values higher than 7 is alkaline. pH also have influence on the toxicity level of several nutrients such as ammonia concentration,

which will turn toxic to aquatic organism in low pH. pH values were observed changing from slightly alkaline to alkaline condition in the surface and bottom layers in the mangroves areas.
Nutrient loadings from human induced activities and the decompositions of dead aquatic organisms will produce ammonia, which induced alkaline condition.
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What is Salinity?

Salinity is a measure of how much salt is in the water.
Salinity is usually measured in parts per thousand (ppt) units. Parts per thousand is how many grams of salt are dissolved per liter of water.
Why is Salinity Important?

All plants, animals, bacteria, and algae need a certain salinity range in order to survive. Changes in salinity can kill an organism.
The salinity in the Neuse River and Pamlico Sound can range from 0ppt to 35ppt. Read more.......


Chlorophyll-a – A plant pigment whose concentration in water is used to estimate the amount of phytoplankton or algae.

Plants and algae use this pigment to trap the energy from the sun so they can grow. Chlorophyll a is measured in micrograms per liter ( µ g/l) units. Micrograms per liter is micrograms of chlorophyll a per liter of water. In estuaries, chlorophyll a measurements can range from 1 µ g/L to higher than 20 µ g/L.
Scientists measure chlorophyll a in the lab by separating the chlorophyll a from the
algae in the water.

Why is Chlorophyll a Important?

Chlorophyll a tells us how much algae is in the water. Algae are small plant-like organisms that float in the water and use the sunlight to grow. Too much algae can cause problems. As algae die, bacteria eat them. This can lower the oxygen in the water since bacteria need oxygen to grow. If there is no oxygen, some of the animals and plants in the water can die!
Some algae are poisonous to fish, shellfish, and even humans.
Read more.......

What is Total Suspended Solid?

What are they?
TSS are solid materials, including organic and inorganic, that are suspended in the water. These would include silt, plankton and industrial wastes.

High concentrations of suspended solids can lower water quality by absorbing light. Waters then become warmer and lessen the ability of the water to hold oxygen necessary for aquatic life. Because aquatic plants also receive less light, photosynthesis decreases and less oxygen is produced. The combination of warmer

water, less light and less oxygen makes it impossible for some forms of life to exist.

Suspended solids affect life in other ways. They can clog fish gills, reduce growth rates, decrease resistance to disease, and prevent egg and larval development. Particles that settle out can smother fish eggs and those of aquatic insects, as well as suffocate newly-hatched larvae. The material that settles also fills the spaces between rocks and makes these microhabitats unsuitable for various aquatic insects, such as mayfly nymphs, stonefly nymphs and caddisfly larva.

Suspended solids can result from erosion from urban runoff and agricultural land, industrial wastes, bank erosion, bottom feeders (such as carp), algae growth or wastewater discharges.

Prevention methods include protection of the land in our watershed from erosion by use of conservation tillage measures and giving urban runoff time to settle out before reaching our surface waters.

TSS of a water sample is determined by pouring a carefully measured volume of water (typically one litre; but less if the particulate density is high, or as much as two or three litres for very clean water) through a pre-weighed filter of a specified pore size, then weighing the filter again after drying to remove all water. The gain in weight is a dry weight measure of the particulates present in the water sample expressed in units derived or calculated from the volume of water filtered (typically milligrams per litre or mg/l).

Recognize that if the water contains an appreciable amount of dissolved substances (as certainly would be the case when measuring TSS in sea water), these will add to the weight of the filter as it is dried. Therefore it is necessary to "wash" the filter and sample with deionized water after filtering the sample and before drying the filter. Failure to add this step is a fairly common mistake made by inexperienced laboratory technicians working with sea water samples, and will completely invalidate the results as the weight of salts left on the filter during drying can easily exceed that of the suspended particulate matter.

Although turbidity purports to measure approximately the same water quality property as TSS, the latter is more useful because it provides an actual weight of the particulate material present in the sample. In water quality monitoring situations, a series of more labor intensive TSS measurements will be paired with relatively quick and easy turbidity measurements to develop a site-specific correlation. Once satisfactorily established, the correlation can be used to estimate TSS from more frequently made turbidity measurements, saving time and effort. Because turbidity readings are somewhat dependent on particle size, shape, and color, this approach requires calculating a correlation equation for each location. Further, situations or conditions that tend to suspend larger particles through water motion (e.g., increase in a stream current or wave action) can produce higher values of TSS not necessarily accompanied by a corresponding increase in turbidity for the reason that particles above a certain size (essentially anything larger than silt) are not measured by a bench turbidity meter (they settle out before the reading is taken) but contribute substantially to the TSS value.

Definition problems
Although TSS appears to be a straightforward measure of particulate weight obtained by separating particles from a water sample using a filter, it suffers as a defined quantity from the fact that particles occur in nature in essentially a continuum of sizes. At the lower end, TSS relies on a cut-off established by properties of the filter being used. At the upper end, the cut-off should be the exclusion of all particulates too large to be "suspended" in water. However, this is not a fixed particle size but is dependent upon the energetics of the situatuion at the time of sampling: moving water suspends larger particles than does still water. Usually it is the case that the additional suspended material caused by the movement of the water is of interest.

These problems in no way invalidate the use of TSS; consistency in method and technique can overcome short-comings in most cases. But comparisons between studies may require a careful review of the methodologies used to establish that the studies are in fact measuring the same thing.

TSS in mg/L can be calculated by (dirty pad weight in grams - clean pad weight in grams)/ ml of sample * 1,000,000

Wikipedia link here
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What is turbidity?

Turbidity is a measure of the degree to which the water looses its transparency due to the presence of suspended particulates.
The more total suspended solids in the water, the murkier it seems and the higher the turbidity.

Turbidity is considered as a good measure of the quality of water.

What causes turbidity?
There are various parameters influencing the cloudiness of the water. Some of these are:

- Phytoplankton
- Sediments from erosion
- Resuspended sediments from the bottom (frequently stir up by bottom feeders like carp)
- Waste discharge
- Algae growth
- Urban runoff

Which is the maximum allowed turbidity in drinking water?
The WHO (World Health Organization), establishes that the turbidity of drinking water shouldn't be more than 5 NTU, and should ideally be below 1 NTU.

What are the consequences of high turbidity?

The suspended particles absorb heat from the sunlight, making turbid waters become warmer, and so reducing the concentration of oxygen in the water (oxygen dissolves better in colder water). Some organisms also can’t survive in warmer water.

The suspended particles scatter the light, thus decreasing the photosynthetic activity of plants and algae, which contributes to lowering the oxygen concentration even more.

As a consequence of the particles settling to the bottom, shallow lakes fill in faster, fish eggs and insect larvae are covered and suffocated, gill structures get clogged or damaged…

What are the impacts of turbidity?
The main impact is merely esthetic: nobody likes the look of dirty water.

But also, it is essential to eliminate the turbidity of water in order to effectively disinfect it for drinking purposes. This adds some extra cost to the treatment of surface water supplies.

The suspended particles also help the attachment of heavy metals and many other toxic organic compounds and pesticides.

Here is the beginning of my post. And here is the rest of it. Read more.......

What is Secchi Disc

The Secchi disk originated with Fr. Pietro Angelo Secchi, an astrophysicist, who was requested to measure transparency in the Mediterranean Sea by Commander Cialdi, head of the Papal Navy. Secchi was the scientific advisor to the Pope. Secchi used some white disks to measure the clarity of water in the Mediterranean in April of l865. Various sizes of disks have been used since that time, but the most frequently used disk is an 8 inch diameter metal disk painted in alternate black and white quadrant .
Click this link for more information about Secchi Disc
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