Cape Reinga is the most northerly accessible point of the North Island, although in actual fact North Cape (30 kilometers or 18 miles to the east) are slightly further north. It is of great significance to the Maori people and, despite its remote location, is a very popular tourist stop. Anywhere you may look at there will be water all around. Cape Reinga is generally considered the separation marker between the Tasman Sea to the west and the Pacific Ocean to the east. From the lighthouse it is possible to watch the tidal race, as the two seas clash to create unsettled waters just off the coast.
WATER ON THE OCEANS = SALT WATER=
1. WATER MOVEMENTS = The sea is constantly on the move, driven by tides, winds and changes in temperature and salinity. Tides are water movements mainly driven by the gravitational pull of the moon and sun on the ocean. The moon has the most influence as it is the closest to earth.The moon rotates around the earth in about one day. Its gravity attracts a bulge of water (high tide) that travels around the earth.
2. WATER MASSES IN THE OCEAN = A shallow, well-mixed layer, approximately 50 to 200 meters thick, forms the surface layer of the oceans, the mixing resulting from the effect of wind and waves. The vertical differences of temperature and salinity within this layer are very small but the water properties can change fairly rapidly because the layer is subjected to solar radiation, evaporation, and precipitation. At the bottom of this layer there is a region where the vertical temperatures decrease rapidly over a small depth, with consequent sharp changes in the density of the water. This region is called the thermocline and mixing cannot proceed rapidly there because of the steep density gradient which exists. As a result, water properties such as temperature and salinity do not change quickly below the thermocline. These conservative properties are used to classify oceanic water into various “water masses”, and the movement of these water masses can be traced over long distances. This fact is used as a subsidiary method of determining currents. Different water masses exist at different depths and a vertical section may consist of an upper, intermediate, deep, and bottom water mass.
New Zealand is bathed from the west by three major water masses. The boundaries of these masses are called fronts. These can be seen in the diagram as the Tasman Front (TF), Subtropical Front (STF) and Subantarctic Front (SAF). The Tasman and Subtropical fronts are relatively warm surface currents.
GROUND WATER / RAINFALL = FRESH WATER=
Cape Reinga has a very mild climate with high precipitation and little difference between the seasons; on balance 1057.9 mm (41.6 in) of rainfall per year, or 88.2 mm (3.5 in) per month. The driest weather is in December when an average of 61.4 mm (2.4 in) of rainfall (precipitation) occurs. The wettest weather is in July when an average of 128.7 mm (5.1 in) of rainfall (precipitation) occurs.
This conditions may look really good for plants: lots of water and mild temperatures... But look around!! Is there any big tree around? Plants growing near the coast are subjected to extreme environmental conditions much different than those growing further inland. Factors such as blowing sand, poor soils, high temperatures, and excessive drainage all influence how well plants perform in coastal landscapes, though the most significant effect on growth is salt spray. Most plants will not tolerate salt accumulating on their foliage, making plant surviving in coastal landscapes particularly challenging. Salt spray is created when waves break on the beach, throwing tiny droplets of salty water into the air. On-shore breezes blow this salt laden air landward where it comes in contact with plant foliage. The amount of salt spray plants receive varies depending on their proximity to the coast, creating different vegetation zones as one gets further away from the coastfront. The most salt-tolerant species surviving in the frontal area. As distance away from the ocean increases, the level of salt spray decreases, allowing plants with less salt tolerance to survive.
To claim this Earth Cache, please e-mail me the answers to the following questions:
1. What do you think this meeting point is: just a meeting of superficial currents? or a clash of two big water masses?
2. Pay attention to the area where the meeting point is happening: is it just next to the coast? spreading into the water? irregular shape? a triangle maybe?. What could be causing the waves and whirlpools in the day you are observing the clash? Could it be the wind? Could it the tides moving?
3. If you are driving southwards, you may see some pockets of native forest that once almost covered all New Zealand, now mostly gone due to severe lumberjacking in the past. Do you think that this native forest could have ever covered the Cape Reinga back in the time?
4. If you want, attach a photo of the meeting point to check how does it look depending on the day. But do not attach the answers. Thank you