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This project – The Effects of PH and Salinity on the Respiratory Activities of African Lungfish Protopterus annectens – has been a fascinating and enlightening experience. With the completion of this analysis, we believe that human activities such as farming and mining have been exposed to significantly contribute to the acidification of Nigeria’s natural waterways as a result of chronic or acute bouts of low PH caused by pollution.

It is also our hope that this work would inspire fresh faith in our biologists’ ability to care for and manage our environment. The results of this experiment reveal that low and very high PH due to pollution have the most noticeable effects. Fishes exhibit respiratory distress signs at low PH due to the coagulation of mucus on their gills. The effect, on the other hand, is highly noticeable at high salinity levels.

This means that fishes increase their respiratory rate at salinities closest to the osmotic content of their bodily fluids. However, deviations from normal internal medium concentration and composition result in metabolic problems and, eventually, mortality.



1.1 Context of the Study

In consequence, the Longman Pocket English Dictionary (2001) merely defined the term “EFFECTS.” According to the Oxford Advanced Learner’s Dictionary by Hormby (2001), a more detailed definition of the same term is: a change that someone or something causes in someone or something else. F.G. and H.N. Fowler (2002) defined “EFFECT” as the Result of an Action’s Consequence.

In addition to shedding light on the impression produced on a viewer or listener, the term “EFFECTS” also endeavours to bring about, accomplish, or cause an event to occur. The preceding definitions imply that the term “EFFECTS” can be used in various contexts, including:

(i) To state the actual circumstances of a situation.

(ii) To initiate the production of desired outcomes

(iii) To indicate that you are providing the general meaning rather than the exact terms of what someone has said or written.

In this context, “EFFECTS” is used to describe how something comes about. In this project’s topic sentence, environmental conditions are anticipated to influence the respiratory activities of aquatic organisms, including the African lungfish.

Analyzing the topic sentence critically reveals essential terms such as EFFECTS, PH, SALINITY, and RESPIRATION. Now that the word EFFECTS has been thoroughly discussed, we will move on to the others.

According to Butani (2006), this symbol PH represents HYDROGENE POWER in French. In the English vernacular, however, it stands for HYDROGEN POWER. According to the author, PH represents the relative concentration of Hydrogen ions in solution. This indicates that the acidity or alkalinity of a medium can be expressed. The PH metre is the instrument used to determine the PH of a solution or medium.

Ababio (2001) observed that the acidity of a solution can be quantified by the extent to which protons are transferred to water molecules to form Hydronium ions (H3O+). Additionally, he opined that the alkalinity of the same solution can be determined by the degree to which it removes protons from water.

The PH of a solution can also be calculated from the quantity of H3O+ (Hydronium ions) or OH (Hydroxyl ions) formed in water solutions of acids or bases, respectively. Therefore, PH equals the negative logarithm of the concentration of hydronium ions.

PH is calculated mathematically as -log [H3O+].

The significance of PH cannot be overstated; therefore, some of its significance is described below.

i. Food digestion in the stomach requires an acidic environment, whereas food digestion in the small intestine requires an alkaline environment.

ii. Correct PH levels must be maintained in bodily fluids. Abnormalities from these values may indicate illness. Normal human blood has a ph of 7.4.

iii. PH values are essential in pharmacy, medical water purification, effluent treatment, and a number of industrial processes.

Most plants thrive in substrates with a pH between 7 and 5.

Butani (2006) defined salinity as the measure of a body of water’s saline. According to him, salinity is the measure of the salt content of sea water. Consequently, we can conclude that salinity is the degree of saline of a body of water. In his terms, 3.5% of the mass of a quantity of sea water is composed of salts, which are present in marine ecosystems’ water. Miller and Harley (1996) identified the following as the five (5) ecosystems:

i. Estuaries

ii. Littoral zones

iii. Benthic zones

iv. Oceanic zones

v. Coral ecosystems

After spending so much time discussing physical factors such as pH and salinity, it is time to discuss respiration. Therefore, the following paragraph focuses solely on the respiration process in fish. According to Emeka (2008), respiration is the process by which digested food is broken down in the body to release Energy.

This is an instance of oxidation. As waste products, carbon dioxide (O2) and water are released. Below is the chemical equation representing this product.

C6H12O6 + 6O2 ⇒ 6CO2 + 6H2O + Energy

Glucose Oxygen Dioxide Water or 36 molecule


Respiration in fishes involves the inhalation and exhalation of air and the release of energy through a chemical reaction in their body cells. It entails both physical and chemical processes known as GASEOUS EXCHANGE or EXTERNAL RESPIRATION. The term for this chemical process is FOOD OXIDATION or INTERNAL RESPIRATION.

External respiration, according to Miller and Harley (1996), is the inhalation of air or oxygen into the respiratory organ. This is referred to as INSPIRATION. This is followed promptly by the exhalation of carbon dioxide and water vapour into the atmosphere, also known as EXPIRATION.

Furthermore, they believed that internal or tissue Respiration is the cellular oxidation of food, which releases energy, carbon dioxide, and water. Consequently, based on the aforementioned definitions, we can deduce the principal facts associated with respiration.

oxygen intake

ii. Oxidation of the goods in the stores

iii. Release of carbon dioxide and a minute amount of water vapour

iv. release of energy from the decomposition of organic food materials.


Hornby (2001) defined a variable as something that alters frequently or is likely to change. According to this definition, the most prominent keyword is “CHANGE.” Consequently, phenomena, conditions, situations, quantities, and numbers that can vary or be varied are known as variables.

According to the hypothesis of Abugu (2009), variables can adopt the values of constants. A variable is a symbol, such as x, h B, that can adopt any of a set of constant values. Consider additionally the following mathematical expression:

y = mx + c

Where y, M, and C are variables, with M and C having variable or changeable values. y’s value is determined by the values of m and c. Consequently, y is a dependent variable and M and C are independent variables.

However, a closer examination of this topic reveals that the two independent variables are PH and SALINITY, while the dependent variable is EFFECTS.

It has been reported that acidification of natural waters as a consequence of a low pH causes fish deaths. This occurs as a result of the fishes’ respiratory distress. On the other hand, it has been observed that aquatic organisms vary in their saline concentration tolerance.

1.2 Statement of problems

i. Limited water supply availability within the college’s grounds

ii. The stoichiometry and volumetric analysis of the employed reagents.

At what pH should the fish’s respiratory Activity be at its peak?

How will respiratory activity change at PH values of 4, 6, 8, and 9?

v. At what salinity level can optimal respiratory activity be anticipated?

vi. How do fish breathe at salinity levels of 1 part per thousand (1), 5 parts per thousand (5), 10 parts per thousand (10), and 15 parts per thousand (15)?

1.3 Objectives of Research

The objective of this endeavour is to examine the effects of salinity and pH on the respiration of African lungfish. (Protopterus annectens).

According to Miller and Harley (1996), Protopterus annectens is adapted to a habitat similar to that in which the fish terrestrial vertebrates are believed to have evolved, so information about the effects of different environmental parameters on their respiratory activities may help to explain how the ancestors of tetrads were able to colonise terrestrial habitat.

1.4 Field of Study

This study is based on observations of the effects of varying PH and salinity levels on the respiratory activities of P. annectens in aquatic environments.

1.5 Research Concerns

i. What are the mass-to-volume ratios of the reagents utilised in this study?

ii. At what PH level are optimal respiratory activities anticipated?

iii. What PH value has the most pronounced influence on the fish’s respiratory activities?

iv. At what PH value can we anticipate to observe the most respiratory disturbance and distress?

v. Which salinity value has the most pronounced effect on the respiratory activities of fish?

vi. Is there a correlation between the fishes’ mass in grammes (g) and their respiratory activities?

1.6 Importance of Study

This work – The effects of PH and salinity on the respiratory Activities of African lungfish, Protopterus annectens – has been a very interesting and enlightening endeavor, as human activities such as farming and mining have contributed significantly to the acidification of natural waters in Nigeria as a result of chronic or acute episodes of low PH due to pollution.

We also believe that this work will inspire renewed faith in our biologists’ abilities to preserve and manage our natural environment.

1.7 Hypothesis

According to Atkins and James (1998), the molarities of H3O+ and OH- vary by multiple orders of magnitude. According to them, they may be as low as 10-14 mol L-1 in certain solutions.

Hence, PH = Log [H30+].

They hypothesised that the logarithm in the preceding definition is a base-10 common logarithm. In addition, they opined that [H3O+] in the molarity of H3O+ ions, with units of moles per litter, reflects their opinion. For instance: When the molarity of [H3O+] ions in purified water is 1.0 x 10-7 mol 2-1 at 25°C, the pH is:

PH = -Log (1.0 x 10-7) = 7.00.

The negative indication in the PH definition indicates that the PH decreases as the H3O+ molarity increases.

Miller and Harley (1996) observed that organisms with a broad range of tolerance to varying salt concentration are Euryhaline, whereas those with a restricted range of tolerance to varying salt concentration are stenohaline.

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