Chemical Oceanography - 04 Introduction to the Physics and Biology of the Ocean The School of Marine...

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Chemical Oceanography - 04

Introduction to the Physics and Biology of the Ocean

The School of Marine Sciences and Marine Environment

Ruppin Academic Center

Gitai Yahel (Yahel@Ruppin.ac.il), Tel.(09)866 3497 #110, Skype gitaiyahel, Web http://moodle.ruppin.ac.il

Monday, April 10, 2023 Chemical Oceanography, Yahel@Ruppin.ac.il (2)

The vertical structure of the ocean

Aphotic Deepsea ~3.8 km

Thermocline

Epipelagic zone

Station 230, East Atlantic, 1 Nov 1974, MedAtlas

Thermocline, nutricline, below 50-500 m

illuminated, warm, productive nutrient depleted, saline, 10-200 m

Permanent thermocline

The ocean interior (90% of the ocean volume)DeepColdDarkStableLow biological activity

Water cycle, major reservoirs and fluxes

Environment Water Volume (km3)

Percentage of Total (% )

Surface Water Freshwater Lakes 125,000 0.01 Saline Lakes and Inland 104,000 0.009 Seas Rivers and Streams 1,200 0.0001 Total 230,000 0.019 Subsurface Water Soil Moisture 67,000 0.005 Ground Water (shallow, <750m) 4,000,000 0.3 Ground Water (deep, 750-4000m) 5,000,000 0.38 Total 9,067,000 0.685 Ice Caps and Glaciers 29,000,000 2.05 Atmosphere 13,000 0.001 Biosphere 600 0.00004 Oceans 1.37 x 109 97.25 Total 1.408 x 109

Surface Sea Temperature distribution

• The sun is the major source of energy to the ocean

• Heat redistribution derive the global circulation

http://earth.usc.edu/~stott/Catalina/Oceans.html

An animation of average Sea Surface Temperature

NASA: http://svs.gsfc.nasa.gov/vis/a000000/a003600/a003652/

Latitudinal precipitation and salinity distribution

Surface seawater salinities largely reflect the local balance between evaporation andprecipitation.

Global salinity distribution

• Ocean Salinity is fairly constant

Average Sea Surface Salinity

Monday, April 10, 2023 Chemical Oceanography, Yahel@Ruppin.ac.il (11)NASA: http://svs.gsfc.nasa.gov/vis/a000000/a003600/a003652/

Regional thermocline structure

Sarmiento and Gruber 2005 Chapter2a

Tropics

General circulation – surface currents

• The great gyres are the most prominent feature of the surface circulation

General circulation – surface currents

Upwelling zonesThe deep water that surfaces in upwelling is cold; by looking at Sea Surface Temperature maps we can identify cool upwelled water versus hotter surface water.

Equatorial Upwelling

Water Flow

Upwelling

Coastal Upwelling

Schematic of thermohaline circulation.

Sinking

The Thermohaline Circulation – The Great Ocean Conveyor Belt

North Atlantic circulation

• North Atlantic Deep Water (NADW) • Sources: Greenland Sea (80%) and Labrador Sea (20%)

Characteristics: Temperature of 2.5º C and salinity of 35.03

• North Atlantic deep water forms as warm, saline waters from the Gulf Stream moves northward, cooled and become more dense.

http://earth.usc.edu/~geol150/variability/deepocean.html

The great global conveyor – simplified scheme

The great global conveyor

from Aguado and Burt, Understanding Weather & Climate

Implication for chemical oceanography

• Distinct Horizontal distribution pattern of chemicals in the ocean – the ocean is NOT fully mixed!o Mixing time 103 yearso Uneven distribution

of chemicals due to: Salinity Removal (e.g. burial) Addition (e.g., rivers) Transformation

(e.g., photosynthesis)

Biological oceanography - the major players:

Primary producersGrazers

Decomposers+

Energy and mass transfer – we use a simplified scheme

Energy Flow

Passage of energy between trophic levels

Bio-geo-chemical cycling - mass cycled, energy is wasted…(as heat)

Macro nutrients cycling

Mass balance and energy transfer

Chemical Oceanography - 04 Introduction to the Physics and Biology of the Ocean The School of Marine...

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