Journal #5

Done by: Koh Wan Xin 2E2

Like stated in this passage, I like most people, used to believe mangroves were muddy and mosquito infested swamps but because I read more about mangroves I now know that mangroves are a very important wetland ecosystem. I was aware that from the passages before, that an estimated 75 percent of fish caught commercially spend some time in the mangroves or are reliant on food chains tracing back to these coastal forests along with the fact that mangroves protect the coast by absorbing the energy and absorbing pollution.

The information that, as general rule zones of dominant mangrove species runs parallel to the shoreline or to the banks of tidal creek systems that there were grey mangroves was new to me. I find this passage to be more explanatory that the others I have read as they tell you about the zones in the mangroves, it describes about the soil in that zone and the type of mangroves that will grow there such as yellow mangrove grow where the soil is firmer but more saline due to the evaporation of water leaving behind salt which will not be diluted until the next spring tide.

Unlike other passages this passage informs me more about the three ways how mangroves deal with salt. The first way for many mangroves is to prevent much of the salt from entering by filtering it out at root level. Second way is quickly excrete salt which has entered the system by special salt glands. Last method of coping with salt is to concentrate it in bark or in older leaves which carry it with them when they drop. I learnt about the requirements of mangroves to occur, they need tropical and sub-tropical areas where the water temperature is greater than 24ºC, where the annual rainfall exceeds 1250mm. Then again, Different mangrove species have different requirements. I am very surprised that mangroves have so many different types of roots. Radiating cable roots provide support. Many little nutritive roots feed on the rich soil just below the surface. The third kind of root collects the oxygen. I found out that the fruits, seeds seedlings of all mangrove plants can float, some fertilised seeds grow out from the base of the fruits and begin to germinate but, do not drop from the plants. Live seedlings produced by some other species but they are contained within the seed coat when it drops from the plant in spite of this seeds can stay alive in the water for only three to four days. Seeds with large storage ability may survive longer. I was amazed when I discovered that more than 10 billion bacteria can be found in a teaspoon of mud from a north Queensland mangrove forest, an indication of the enormously high productivity of this coastal forest habitat.
(468 words)

https://www.epa.qld.gov.au/nature_conservation/habitats/wetlands/wetlands_habitats/mangroves/