Question

Explain some environmental conditions that characterize ecosystems in the ocean depths.

Answer 1

Marine ecosystem is the largest biome in the world and is home to millions of plants and animals. In oceans there are a number of environmental conditions that affect the growth, survival and productivity of marine organisms. These conditions include climate, salinity, light availability, oxygen levels, water movement, density and pH.

i] Climate: Depth and temperature greatly impact all life in the marine biome. shallow oceans or those near the equator will have a higher temperature than those near the poles. The average water temperature of the marine biome is 39 degrees Fahrenheit (4 degrees celcius), but can be colder or warmer depending on location.

ii] Salinity: Salinity of seawater varies considerably throughout the world's oceans. Marine water is generally composed of about 96.5% of pure water and 3.5% dissolved compounds. Most seawater has a salinity of approximately 3-4% and it can also reach upto almost 40% in some areas. It is typically highest in isolated water bodies as the evaporation rates are high and precipitation rates are low nd typically low in estuaries as there is regular mixing with freshwater source. Marine animals are adapted to maintain their body salts at constant level.

iii] Light availability: Many organisms in marine ecosystem depend upon presence of light and nutrients to thrive. Photosynthesis can only occur when enough light penetrates down the water column. Photic zone is the area where sunlight can penetrate the water and is approximately 150 m deep where photosynthesis can take place. Photosynthesis cannot occur in water depth greater than 150 m as light can't penetrate.

iv] Oxygen levels: It is very important gas in the ocean as it plays an important role in the life processes of marine animals. Dissolved oxygen in seawater comes from mixing (where surface meets the atmosphere) and as a byproduct of photosynthesis. Most of the oxygen rich water is found near the surface and thus majority of marine animals live in that region.

v] Water movement: Movement of water in the form of waves, tides and currents plays an important role in oceans and impacts on all marine organisms. Waves are caused by winds acting on the surface of sea. They cleanse organnisms and help to increase oxygen availability. The impact of awves generally reduces with depth. Tides have biggest impact on marine organisms that live on coastlines. currents play an important role in moving water between poles and tropics. It also moves food and nutrients from the coast to further out into the sea. Many organisms rely on currents to transport their eggs and larvae.

vi] Density: Seawater is more than 800 times denser than air. The high density is related to salinity and temperature. This also means that objects that might sink in freshwater are able to float in seawater which might affect the life in the sea.

vii] pH: The pH of seawater is about 8 but can also vary. A silght change in the pH of oceans cam have significant impact on the life. As the pH of ocean is gradually decreasing, acidification may potentially decrease marine biodiversity on a large scale.