Abstract

This study was an inquiry into the effects of the four primary moon phases on sea tide, using Forcados sea (river) as a case study. The height of high and low tides at the moon phases from the new, first quarter, and full to last quarter moon were observed and recorded using a tidal gauge. The result obtained was then used to determine spring and neap tides respectively. With a datum of 1.0 m, the average heights of high and low tides recorded were 5.22 m and 1.14 m, 3.45 m and 1.57 m: 5.17 m and 1.17 m and 3.39 m and 1.58 m for the new, first quarter, full and last quarter moon phases respectively. These were then plotted to determine spring and neap tides, corresponding to the new and full moon phases, and the first and last quarter moon phases respectively. It was concluded that maximum phase peaks correspond to a high tidal range and hence represent spring tides, occurred during the new and full moon phases and are associated with higher gravitational force from the moon; higher sea current, flooding, higher tidal range, higher speed of sea current etc. that’s not good for fishing activities. The minimum phase peak corresponds to a lower tidal range and therefore represent the neap tide that occurred during the moon’s first and last quarter phases, which is associated with lower gravitational force; lower sea current, and lower sea current speed.

Keywords:Primary Moon Phases; Sea Tide; Gravitational Force; Flooding; Sub-Atomic Particles; Galaxies; Universe; Planets; Stars; Cosmic Bodies; Astronomical Bodies; Ocean Tides; Natural Satellite

Introduction

The universe comprises of all existence, any fundamental interaction, physical process, all forms of energy and matter, and the structures they form from sub-atomic particles to entire galaxies. That is, the universe comprises, among other things, the planets, the moons, stars, galaxies, etc.

The moon (lunar) is one of the cosmic bodies or astronomical bodies in the universe that is responsible for the high and low tides that we see on the World’s oceans due to its gravitational pull towards the earth’s surface [1]. Ocean tides are caused by the complex interplay of three astronomical bodies; the sun, the moon, and the earth. Both the sun and moon exert a gravitational pull on the Earth’s water, the resulting force of the moon’s gravity creates two tidal bulges on opposite sides of the Earth. Depending on the relative position of the sun, the tidal bulges will change slightly as the moon experiences its phases [2].

The moon is massive; therefore, its gravitational pull affects bodies of water during certain moon phases (moon cycles), which affects the tide. Due to the combined gravitational pull of the moon and sun, tides occur. Still, the moon is the major force behind tides because it is nearer to the Earth [3]. The moon’s tidal force is 2.21 times larger than the sun’s [4]. At both full and new moon phases, tides are at their most drastic, that is, high tides are very high, and low tides are very low. While at the first and last quarters of the moon phases, the earth’s tides are at their least drastic. That is, the tidal bulge is at its smallest, whereby high tides are not high and low tides are not low [5].

The moon is an astronomical body (or object) that orbits planet Earth, and it is the only Earth’s permanent natural satellite. It is the fifth largest natural satellite in the solar system, and the largest among planetary satellites relative to the size of the planet that it orbits. The moon is, after Jupiter’s satellite Io, the second densest satellite in the solar system among those whose densities are known. Moon’s distance to the Earth is 384,400km with a surface area of 3.79×107 km² (about 0.074% of Earth’s surface area) and its mass is about 7.342×1022 kg (about 0.012300% of Earth’s) [6]. It was formed from debris that resulted from a collision between Earth and a man-sized body called Theia, which caused a big chunk of mass to eject from Earth which later on, cooled down and then became the Moon.

Moon phases are the different ways the moon looks from Earth over about a month. You might wonder why the moon looks different every night. This is because as the earth revolves around the sun, the light reflected to the moon varies every day. A phase of the moon is an angle of the moon to the earth, so it appears differently every day. As the moon orbits around the earth, the half of the moon that faces the sunlight will be illuminated (lit up). The different shapes of the illuminated portion of the moon that can be seen from Earth are known as “phases of the moon” [7]. Each phase repeats itself every 29.5 days and there are eight (8) phases that the moon goes through. See the diagram of the four (4) major moon phases below, in which the effect on the tide is more pronounced.

From the above Figure 1, during new and full moon phases, tides are at their most drastic period. High tides are very high and low tides are very low. The moon, sun, and earth are in a straight line (in alignment) during this period of the moon cycle, and their gravitational forces combine to create large tidal bulges, resulting in what is called “spring tide”.

While during the first and last (or third) quarter moon phases, tides are at their least drastic. During this quarter phase, the moon forms a right angle with the sun, and when this happens, the gravitational forces from each body act against each other, thereby diminishing the overall tidal bulge. That is, the tidal bulge is at its smallest, resulting in what is known as “Neap tide” [8]. Since the moon, as an Earth’s natural satellite with its massive size, is majorly responsible for the high and low tides we experience on the world’s oceans due to its gravitational pull towards the Earth, the researcher therefore, seeks to investigate tidal levels at various moon phases (moon cycle) in the coastal areas of Niger Delta, Nigeria using Forcados river as a case study

The aim was to develop a guide to aid fishing activities within the coastal area of the Forcados River region, as fishing depends on the type of tide. The objectives of the study are to be able to predict the tide of the Forcados River, the minimum tidal level height, the moon phases that occur, and the maximum tidal height and the moon phases that occur [9,10].

For the sake of this research work only four major phases of the moon, in which the effect on the tide is more pronounced will be investigated.

Materials and Methods

The method used in this study was direct observation. The tidal levels at different moon phases from the new, first quarter, and full to last quarter moon phases were observed and recorded daily in the month of April 2024 at Forcados River. The Forcados is a small town, in Burutu Local Government Area of Delta State, Nigeria, which lies on latitude 5°35’57” N, longitude 5°34’59” E. The town is most noted for the Forcados River, which is a navigable channel of the coastal region of the Niger Delta, where most fishing activities are carried out by fishermen.

Materials/Equipment

The following materials and equipment were used during the study: Tidal gauge and Tidal record diary.

Procedure

The tidal gauge was firmly installed at a convenient location on the coast of river Forcados with Datum/LAT of 1.0meter, to take accurate records of tidal levels. Immediately the new moon was observed, and the high and the low tides levels were recorded daily with the aid of the gauge and the recording diary. This was continued throughout the new moon, first quarter moon, full moon, and the last quarter moon lasting for a period of 24 days. The high and the low tide levels were recorded together with the local time.

Calculation

The average high and low tide levels or heights of the tide were evaluated using the average formula.

Where H_T(AV) is the average height of the high tide; is the sum of the height of high tide for a specified period; ΣL_r is the average height of low tide for a specified period; N is the number of high or low tides recorded for a specified period.

Finally, (T_R) the tidal range was evaluated for each moon phase from the average heights for high and low tides to determine spring and neap tides as given below.

Data Presentation

Table 1 gives the result of the observation for a month (April 2024), as recorded using a tidal gauge.

The average heights of low and high tides including the tidal range of each moon phase were deduced from Table 2.

From Table 1, a graph of average heights of low and high tides against moon phases is plotted to obtain the curve below (Figure 2).

From the graph, it was observed that higher high tide and lower low tide occur during new and full moon phases respectively, higher/lower than when it was the first quarter and last quarter moon phases. While high tide and low tide occur during the First quarter and Last quarter moon phases.

Conclusion

From the above, it is concluded that maximum phase peaks correspond to a high tidal range between the high and low tide levels and hence represent “spring tides”. This occurred during the new and full moon phases. This period of the moon is associated with higher gravitational force, high sea current, flooding, etc., therefore fishing activities are limited.

The minimum phase peaks correspond to the low tide range between the high and low tide levels or heights of tide and therefore represent “neap tides” as well. This occurred during the first and last quarter phases of the moon. This period is associated with less gravitational force, low sea current or slow movement of the water, no flooding, etc. Therefore, good for most of the fishing activities to take place.

A good understanding of the effect of moon phases on tidal levels will help in the provision of tidal records and information to aid fishing activities in the coastal regions, as data obtained is used for tidal prediction, to know when it is convenient for fishing and generally to serve as guide for fishermen of their day-to-day fishing activities. Therefore, the government should encourage research activities in this area to provide accurate tidal records and information to aid fishing activities in this country.

References

1. Case F, James P (2000) Understanding Tides from ancient beliefs to present-day solutions to the Laplace Equations. Charlotte, North Carolina SIAM News 33(2).
2. Wahr J (1995) Earth Tides in Global Earth Physics. American Geophysical Union Reference Shelf, pp. 40-46.
3. Munk W, Wunsch C (1998) Abyssal recipes II: Energetic of tidal and wind mixing. Deep-sea Research Part L 45 (1998): 1977-2010.
4. NASA (1990) The Lunar Tidal Force. 2.21 Times Larger Than the Solar.
5. Lisitzin E (1974) Periodical Sea-level Changes, Astronomical Tides (In: 8^th Edn), Northern Eastern Brazil, Parana MC press, Brazil, pp.5.
6. Roger W, Donald W (1999) What's a blue moon? New York City, Sky and Telescope, pp. 23-42.
7. Gaylord J (1934) How Moon and Sun Generate the Tides. Popular Science, pp. 14-16.
8. Ross DA (1995) Introduction to Oceanography. New York, Harper Collins, pp. 236-242.
9. William B, John M (2003) American Merchant Seaman's Manual. Houston Texas Cornell Maritime Press, USA, pp. 9.
10. Mellor GL (1996) Introduction to physical oceanography. Phoenix Arizona, Springer, Pp. 169.