2024 STU1033 Aquatic Science & Daily Life Unit 1 PDF

STU1033 Aquatic Science & Daily Life LU1: Introduction to Aquatic Habitats At the end of the unit, you should be able to: 1. Know the type of aquatic environments and the watershed. 2. Understand water chemistry (e.g. seawater properties). 3. Understand t...

STU1033 Aquatic Science & Daily Life LU1: Introduction to Aquatic Habitats At the end of the unit, you should be able to: 1. Know the type of aquatic environments and the watershed. 2. Understand water chemistry (e.g. seawater properties). 3. Understand the water cycle. Acknowledgement: Notes are adapted from OpenCourseWare@UNIMAS  Types of aquatic environment: 1. Freshwater : rivers, streams, ponds, lakes, reservoirs, ices (icebergs, snows), wetland areas, and groundwater e.g. Mekong River, Kenyir Lake. CAN YOU NAME OTHER FRESHWATER BODIES IN MALAYSIA? AROUND THE WORLD? © FARAH AKMAL IDRUS © FARAH AKMAL IDRUS Lake Snow  Watershed: Geographic boundaries of a water body, its ecosystem and the land that drains to it. Watershed: Including groundwater that receive discharges from streams, wetlands, ponds and lakes. It can be as small as a backyard or as large as the land that drains into the Great Lakes. Image taken from : http://thewhiteriveralliance.org/wp-content/uploads/2013/04/Watershed.jpg  Types of aquatic environment: 2. Brackish water: estuaries, mangroves, brackish seas & lakes, brackish marsh e.g. New York City (Hudson River Estuary), London (Thames River Estuary), Kuala Lumpur (Klang + Gombak Rivers Estuary). CAN YOU NAME OTHER BRACKISH-WATER BODIES IN MALAYSIA? AROUND THE WORLD? © FARAH AKMAL IDRUS © FARAH AKMAL IDRUS River mouth of Malacca Thames River River  Types of aquatic environment: 3. Marine (Sea-Ocean): The marine environment is associated with our seas and oceans. The sea is a saltwater area on the margins of the oceans. Oceans Pacific Ocean (155 million sq km) Atlantic Ocean (76 million sq km) Indian Ocean (68 million sq km) Southern Ocean (20 million sq km) Arctic Ocean (14 million sq km) Cover ~71% from Earth’s surface Our global oceans & seas Can you guess how many seas? Guess what is the main difference between seawater and freshwater? Did you guess taste?  increases SALTY= measured as SALINITY WHICH IS THE SALTIEST WATER??? 'Normal' SALINITY Salinity range: 32 – 37 ppt WHICH IS THE FRESHER WATER??? Salinity have units of parts per thousand (ppt), decreases (‰), [g/kg] and ratio (no UN IT unit-often written as S=37.)  Why is the sea always salty? Decaying biological matter Weathering and erosion processes Rains and streams transport mineral to the sea Dissolved rocks and sediments from the ocean floor Solid and gas material from hydrothermal vents FACT: The proportion of salt + its content in ALL the oceans remain the same! For seawater while the total concentration of dissolved salts varies from place to place, the ratios of the more abundant components remain almost constant (Millero, 1996). Do we have dissolved gases in the seawater? They are involved in biogeochemical cycling e.g. CO₂ used in photosynthesis to produce O₂, O₂ used in respiration to produce CO₂, N used in the nutrient cycle (nitrate, nitrite, ammonia). Dissolved gases are very important in the oceans.  Density of seawater: Where is the densest water? Where is the lightest? Pure water density: 1.000 g/cm³ at 4°C Seawater is usually more dense: 1.022-1.030 g/cm³ Difference in Seawater densities create deep ocean current Do you know other differences in fresh vs saltwater properties? Tip: use your senses to smell, taste and observe Property Freshwater Seawater Odour Odourless Distinctly marine Taste Tasteless Salty pH 7.0 (neutral) 8.1 (slightly alkaline) Density (at 4°C) 1.000 g/cm³ 1.028 g/cm³ Freezing point 0 °C -1.9 °C Boiling point 100 °C 100.6 °C  Hydrological Cycle (Water Cycle): The process of the continual exchange of water between the Earth and the atmosphere. The pathways of water movement and distribution. Hydrological Cycle (Water Cycle): Take 2 minutes and identify the components of the hydrological cycle It should include: precipitation (amount, frequency, intensity, type), evapotranspiration (evaporation plus transpiration from plants), soil moisture, runoff, streamflow and river discharge into the oceans atmospheric moisture flows (e.g. by wind) and divergence, atmospheric moisture storage. Related issues are the co- variability of temperature and precipitation, and forcings of the hydrological cycle, such as solar energy.  Impacts of human activities on the water cycle: Human Activities Impacts Deforestation run-off discharge increase Land clearing Urbanization : soil evaporation high, transpiration low Retain run-off : inland evaporation increase, Man-made groundwater input decrease, wetland areas reservoir may dry out (withdrawal for human usage & irrigation) - Lowering the groundwater table Groundwater - Reduction of water in streams and lakes - Land subsidence - Saltwater intrusion What are some of our daily activities using water which may not be sustainable? - The End of Unit 1 -