1. To understand the structure and functioning of a rocky shore ecosystem.Objectives1.
To measure climatic factors by means of an environmental comparator with a light probe, a whirling hygrometer, a hand-held wind meter, and a thermometer;2. To measure pH of sea water on the spot;3. To sample shore animals by means of a transect line and a quadrant;IntroductionIn this field trip report, Shek O, located in the north-east part of Hong Kong, is chosen as the place for our ecological study because rocky shores there are quite easy to access to and have a wide range of marine organisms.The best time to explore a rocky shore is at low tide, when there is a fairly calm sea, so as to avoid those sudden big waves.
For this reason, we started our fieldwork on Shek O rocky shore at 3 p.m. to avoid the high tide and the tidal information was checked out from the Hong Kong Royal Observatory. On that day, the weather was cool and sometime rainy.
I think it is not the best time for our fieldwork as it might more or less affect the availability or abundant of marine animals found on the rocky shore.Apparatus and materialsFor animal capturing and sampling*aquarium net 1 piece*dip net 1 piece*enamel tray 1 piece*forceps 1 pair*plastic bucket 1 piece*quadrat 1 piece*trowel 1 piece*vials, different sizes 10 piecesfor measuring physical factors*Alcohol-in-glass-thermometer 1 piece*compass 1 piece*cotton thread 1 piece*environmental comparator with light probe 1 set*hand-held wind meter 1 set*meter rule 1 piece*pH paper some*ranging poles 2 pieces*spirit level 1 piece*whirling hygrometer 1 pieceMethodsTo determine the relative humidity1. The reservoir of the hydrometer was fully filled with water and was stoppered.2.
The relative humidity was determined by finding the difference of temperature of the two bulbs and then read off from a special scale providedTo determine the wind speed.1. The wind speed was taken where the plastic ball reached maximum height.pH of sea water.
1. The colour change was compared with a standard scale to find out the pH value.ResultsA table showing the abiotic factors of the rocky shore at Shek OfactorsDetailsTemperature20 ?Wind speed14:50 < 2mph 15:10 =5mphWeatherRainy and cloudyPHI of the sea waterAbout 5-7DiscussionPrinciples of the methods used in the procedures.The whirling hydrowind meterAs the wet bulb is always filled with water, when water evaporates during the whirling action, the temperature on the bulb is lowered and it is lower than the dry-bulbed one.
The difference between the reading of both the dry and wet one can be found out and there is a special scale(an accessory of the windmeter) that provide an easy and convenient way to check out the actual relative humidity.Adaptive features exhibit by the organisms foundAs the rocky shore is constantly under the strong tidal action, animals inhibiting on the shore is always subjected to the threat of being washed away, desiccation, fluctuation of salinity and temperature. They should therefore have some means to protect themselves from the threats in order to survive.ChitonsChitons cling to rocks by using suction.
Their calcareous shell is so hard and strong that are hard to be removed from the rocks. This not only prevents them from being washed away by strong tidal actions but also makes them harder to be a prey of predators.They are mostly herbivores and eat tiny plants (algae) which they scrape off rocks with their rasping tongue or radulaCrabA crab shell is called a carapace and it protects its soft body from predators. Its large claws are used for catching and killing prey.
ConclusionThe most noticeable thing about rocky shores is the zonation of organisms. This is common to rocky shores all over the world. The particular species of organism in each zone may vary with different climates and levels of wave and air exposure, but all show special adaptations to living in this area, and the basic structure is recognisable on most rocky shore environments.
