benthos

Question 1

definition of sediment

Answer 1

natural particles (of differnet size) that loosly accumulate over time. particle need to sink down from surface water

Question 2

what are the 4 main grain sizes?

Answer 2

clay
silt
sand
gravel

Question 3

what are the more coarse grain types?

Answer 3

sand

gravel

Question 4

what are the more fine grain types?

Answer 4

clay
silt

(often called mud)

Question 5

what are the sources for sediments?

what are the 2 main sources?

Answer 5

• terrigeneous
• biogeneous
• hydrogenous
• cosmogenous

terrigeneous and biogeneous are the two main

Question 6

what is the main source for deep sea sedimet?

Answer 6

mostly biogeneous

Question 7

what is ooze ?

Answer 7

sediment containing > 30% biogeneous material

Question 8

what is clay? what does it consists of?

Answer 8

sediment containg < 30% biogeneous material

• -> calcerous clay
• -> silicious clay

Question 9

what are the two types of oozes?

Answer 9

calcareous ooze

siliceous ooze

Question 10

what is calcareous (CaCO3) ooze made of?

Answer 10

of organimsm conating calcium carbonate in their shells/sekelteons
(coccolithophores, foraminifera)

Question 11

what is siliceous (SiO2) ooze made of?

Answer 11

of organisms containg silicia shells

diatoms, radiolarians

Question 12

at what depth is ooze dominating?

Answer 12

deep ocean floor

Question 13

where on the planet can you find large amounts of silicious sediments?

Answer 13

underneath the antarctic circumpolar current

Question 14

which are three river system which release large amounts of sediments in the ocean basin?
(drainage basins)

Answer 14

amazonas
mississippi
ganges

Question 15

how does the sediment thickness linked to drainage basins areas?

Answer 15

sediment thickness increases in drainage basin areas

Question 16

what are the two types of benthic communities?

Answer 16

hard bottom communities

sediment communities

Question 17

sediment communities live in two type of sediments. which?

what are the characterstics of these two ?

Answer 17

sandy beaches (coarse to fine particles)
muddy sediments (fin --> very fine particles)

Question 18

hard bottom communities live in two type of sediments. which?

Answer 18

rocky intertidal shores
hart substrate (boulders, pebbles)

Question 19

name three benthic feeding modes:

Answer 19

suspension(filter feeders
detritus feeder
grazers
bacteriovores
predators

Question 20

what are the characteristics of deep sea floor ?

Answer 20

calm, undisturbed
constant temp.
darkness
high hydrostatic pressure

Question 21

how often does food reaches the sea floor during the year.

why?

Answer 21

1-2 pulses = result of phytoplankton blooms in spring and autumn

Question 22

what are strategys to cope with the food limitations in the deep sea?

Answer 22

chemolithoautotrophs at hydrothermal vents: reduction of m

Question 23

what electron donor and what carbon source do chemolithotrophs use ?

Answer 23

inorganic carbon: CO2

inorganic electron donors: ammonium, H2S

Question 24

where are hydrothermal vents conecentraed globally?

Answer 24

along the ridges

Question 25

give an example for a chemolithotrophs bacteria

Answer 25

sulphur oxidizing bacteria

Question 26

what is typical for the macrofaua of deep sea habitats?

Answer 26

dominated species are:

• crustacaea
• polychaeta

Question 27

how do deep sea benthic communities react to the yearly food pulses ? –> stratgey?

Answer 27

burry the material in the sediment –> = storage, hiding from predators

Question 28

what do alle zoobenthos individuals have in common, what seperates thesm from shallow water indivudlas?

Answer 28

they are often smaller compared.
–> dwafism
related to food shortage

Question 29

name the three zoobenthos groups of the deep sea and give some examples for each

Answer 29

• microfauna (foraminifera)
• meiofauna (nematoda, copepoda)
• macrofauna (polychaeta, crustacea, bivalvia, echinodermata,pisces)

Question 30

what are “lebensspuren”?

Answer 30

life traces in the deep sea, no animal,

we dont know from which species is which lebenspur

Question 31

what is phytobenthos?

give two examples

Answer 31

= autotroph part of the benthos
macroalgae (attached to st
microalga (=biofilm on hard surface)

Question 32

name three types of algae and where they live

Answer 32

macroalgae (attached to st
microalga (=biofilm on hard surface)
small macroalgae (live closely attached to sediments)

Question 33

what dominates sediment community in the euphotic zone?

Answer 33

-microalgae and seagrass

Question 34

what part of the quatic ecosystem has the highest priar production rate?

Answer 34

seagrass meadows (1000 g C/ m2 *year

Question 35

what are the two biofilm constructions/growth patterns?

where do they grow , and which species groups dominate?

Answer 35

sediment:
2 dimensional biofilm; diatoms

hard bottom:
3 dimensional;
epilithon

Question 36

definition of microphytobenthos:

Answer 36

sediment communities of pro and eukrayotic microalgae associated with fungi, bacteria and other protozoa

Question 37

what is benthopelagic coupling?

Answer 37

sedimentation and mixture of benthic of pelagic and benthic communities/environment

Question 38

why is microphytobenthos relevant for the ecosystem?

ecosystem services?

Answer 38

• high primary production
• important high quality food source
• exchange of O2 and nutrients at sediment-water interface
• stabilization of sediment surface?

Question 39

where can you find microphytobenthos?

Answer 39

on the sediment surface in euphotic zone, intertidal areas, estuaries
vertical distribution: 0.2-2m sediment depth

Question 40

what is the migration pattern of benthic macroalage within the seidment horizon?
-how do they move?

Answer 40

move on their slime
during day time: com up as long as there is low tide internal clock: before the tide commes, they dig down in the sediemnte –> so they dont get washed away.