marine ecosystem

-


Marine ecosystem which are of singular ecological significance occupy 70% of Earth's surface,with average depth of 3750m & salinity averaging 3.5%.unlike fresh water ecosystems ,marine ecosystems are continuous & is in continuous circulation via major surface currents , waves , tidal action, upwelling etc. In the absence of vertical mixing of the deep waters which constitute 60% of ocean stay permanently at 3(degrees)celcius. the concentration of nutrients in ocean is low.Hydrogen & oxygen form 96% of total ocean elements.
 
The major zones in marine ecosystems are litoral,neritic,pelagic benthic.
 
a)The litoral or inter-tidal zone:-It is subjected to physical violence of waves & tides & to fluctuations of temperature ,moisture & light intensity. Along rocky shores we find sandy shores organisms are adapted to burrowing in or adhering to sand like- ghost crabs, sand dollars etc. Mud flats occurring in Bays houses algae on the surface & photosynthetic bacteria right beneath it along with abundance of clams, worms etc. Coral reefs may be regarded as litoral ecosystems & is highly productive.

b)The Neritic zone:It constitutes 70% of total ocean area & is rich in species.It has high productivity due to deposition of nutrients washed from land & depth of light penetration. Richness & productivity decreases towards deeper water of this zone.It houses algael communities uni-cellular & multi-cellular organisms apart from snails,worms etc.Phytoplanktons & zooplanktons are abundant & support some of the greatest fishing grounds of the world.

c)Pelagic zone:- It's the open sea & constitute 90% of total ocean surface. Photosynthesis occurs in the surface by planktonic diatoms & dinoflagellates. Copepods & arrow worms are the major types of zooplanktons. 

The zone is low in nutrients & also in primary & secondary productivity. Most plankton live between 75m - 200m from surface. The top milimeter plays an important role in global carbon-di-oxide regulations.The organisms of this zone live below the light penetration are dependent upon detrius & are heterotropic. Carnivores copepods & other crustacea are abundant in upper water of this non-photosynthetic zone. Many animals have reduced vision & others are bio-luminescent, while fishes have light producing organs.

d)Benthic zone:- Extends from the edge of continental shelf to deep ocean trenches. Organisms of this zone are heterotropic. It encompasses 94% of ocean bottom. It is like sea lilies, sponges, other organisms like star fish, sea urchins, clams, snails, diatoms, siliceous & calcerious shelled Forminifera etc.

Comments

Post a Comment

Popular posts from this blog

Distinguish between barotropic & baroclinic conditions of the atmosphere

-
An air mass which is defined as a large body of air whose physical properties especially temperature, moisture & lapse rate are more or less uniform horizontally for hundreds of kilometers.                             barotropic condition of atmosphere is theoretically ideal condition where surfaces of constant pressure are not intersected by isostereic(constant density) surfaces, so that in a vertical cross-section isobars(imaginary lines joining places of equal atmospheric pressure) & isotherms appear parallel i.e,zero baroclinicity.It is a rare phenomenon & is found in case of frontogenesis,separated by baroclinic front zone.          Baroclinic condition of atmosphere is seen in comparatively narrow zones (perhaps 1000Km. in width) of thermal discontinuity also known as fronts in air mass property. They are belts of sharp meteorological gradient recognized as distinct factors in the origin of mid-latitude disturbances. The instability is associated with rising wa
Read more

Airtel DTH: Error B001/Error B003 and Why I left Airtel possibly for Better

-
Image
Why did I decided to Leave?  It has been 2 weeks since I complained about B001 error and Airtel in between replaced 2 set top boxes but problem remained. I have replaced everything as per "diagnosis" of airtel DTH technician but no solution could be reached. Currently, my balance has been deducted from INR200 to INR 10. There are discrepancies with the bills issued against parts replacements conducted during this period. It must be stressed here that I as a customer felt cheated, neglected, harassed by Airtel +Service Partner and I was a 7-8 years+ customer. We never saw that set top box seals were broken in front of our eyes for both the replacements by technicians. My comparison chart for new service provider
Read more

Why do isotherms shift north & south from season to season?

-
An isotherm is an imaginary line drawn on a weather chart or map to join places of equal temperature. Temperature varies from season -as there is high temperature during summer & low temperature during winter with minor changes during transitionary seasons. We know that temperature is proportional to atmospheric pressure & inversely proportional to density.                                                        A.P.=K*D*T                                                           T=A.P*1/D where,A.P.=atmospheric pressure;K=constant;D=density;T=temperature      During the summer season in either of the hemisphere's the sun is vertically overhead of the tropic of cancer/capricorn.The land which has a low specific heat capacity & also being a bad conductor of heat re-radiates the heat to the atmosphere resulting in the spreading of molecules of atmospheric gases due to the heat energy. As molecules spread over a wide region it's pressure on the land becomes l
Read more