”the microbial loop”

The classic marine pelagic food chain:

Aurelia aurita - common jellyfish

Medusa

Strobila

Planula- larv

Ephyra- larv

Polyp

Medusae

Strobilae

Planula- larvae

Ephyra- larvae

Polype

Meroplankton-plankton only when they are young

Something about Öresund!

Length 118 km Width 4-28 km

About 13 km3 of water

Average depth 15 m

North going surface current from the Baltic about 60% of the time:

-about 100 km3 per year

ÖRESUND

The research vessel Sabella in Helsingborg

CTD-sond Conductivity = salinity Temperature Depth Oxygen concentration Oxygen (saturation%) Chlorophyll a

Ven 2004-10-05

salinity

temperature

oxygen concentration chlorophyll

density

oxygen saturation

10

20

30

40

50

Helsingborg Ven Copenhagen

9‰ 11‰

30‰

The water system of Öresund:

bild: S-B Johnsson

Öresund

Saltholm (2-3 m depth)

Knähaken (≈ 30 m depth)

vertical zonation on the west coast

normal removing starfishes blue mussels!

starfish

blue mussels

barnacles

gooseneck barnacles

seaweed

biotic interactions....

5 mm

microalgae

coral polype

sunlight

CO2 + H2O org.mat. + O2

coral

The symbiosis:

nutrients CO2 H2O

microalgae

CO2 + H2O org.mat. + O2

Only 1-5% of the production in the euphotic zone sediments to the deep sea….

Deep sea

Deep-sea viper fish

Food is scarce!

Argylopelecus olfersi (Olfers silver hatchet)

Using light as camouflage in darkness!

Invisible - from below…...

”bioluminiscence”

.

light

inte

nsity

400 500 600 700 800 nm

wavelength (nm)

light at the surface

300 m depth

light from the

Argylopelecus

filter

reflect- ing walls

blue-green light

light emitting cells

How it works:

light from the light emitting cells

Using bioluminiscence to find a partner:

WOW!

Male

Female

What is bioluminiscence?

Light produced by a chemical reaction in an organism:

luciferine oxyluciferine

luciferase

+ oxygen

The submarine Alvin discovers ”hydrothermal vents” with a completely new ecosystem at a volcanic area in the Pacific Ocean outside the Galapagos Islands

1977

2500 m

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime och enCinepak-dekomprimerare

krävs för att kunna se bilden.

Black smoke: different metal sulphides and hydrogen sulphide

Precipitation of metal sulphides

Up to 350°C!

How can all these animals survive and have such a high production in an environment without photosynthesis?

QuickTime och enVideo-dekomprimerare

krävs för att kunna se bilden.

Algae:

6CO2 + 6H2O C6H12O6 + 6O2

Photosynthesis:

Sulphur bacteria:

CO2 + H2S + O2 CH2O + SO42- + 2H+

Chemosynthesis:

The energy in the hydrogen sulphide is used!

Light energy

CO2 + H2S + O2 CH2O + SO42- + 2H+

H2S

CO2 O2

Chemosynthetic bacteria

H2S

H2S O2

CO2

CH2O