Soft sediment ecosystems

Question 1

primary sediment properties

Answer 1

size
shape
orientation
nature (charged clays, organics?)

Question 2

what do primary sediment properties influence?

Answer 2

secondary sediment properties

Question 3

secondary sediment properties

Answer 3

porosity
permeability
orientation
surface area

Question 4

Horizontal wave exposure gradient

Answer 4

variation in wave fetch between shores… and within shores

Question 5

what determines a beach’s characteristics?

Answer 5

key drivers are particle size, wave energy and tidal range (not covered)

Question 6

what does swash and backslash do?

Answer 6

‘plane’ the beach surface

Question 7

Why is permeability of sediment important?

Answer 7

important for delivering food and oxygen to organisms

Question 8

what is penetrability a factor in what animal behaviour?

Answer 8

burrowing

Question 9

horizontal gradients of water motion caused by

Answer 9

edge waves
tides
wind
infragravity waves

Question 10

swash forces dominates when?

Answer 10

sediment is coarse

Question 11

what does sediment building up lead to?

Answer 11

A steeper beach

Question 12

what is a Reflective beach?

Answer 12

minimal wave-energy dissipation
most incident wave energy is reflected back offshore by the nearshore morphology.

Question 13

what is a dissipative beach?

Answer 13

dissipative systems with wide surf zones and high turbulent energy dissipation

Question 14

jaramillo 1994

Answer 14

difference in diversity in beaches in S.America
smaller grain held higher number of species
higher

Question 15

sediment destabilisers

Answer 15

mostly polychaete worms
any burrowers

Question 16

overall effect of sediment destabilisers- effects on habitat (8 things)

Answer 16

1- increasing water- seabed exchange of sediment
2- changing sediment particle composition
3- changing the sediment particle distribution
4- loosening and fluidising the sediment
5- changing the sediment chemistry and microbial metabolism
6- facilitating drainage of sediment at low tide
7- increasing sea bed- water flux of nutrients/metabolites/ other substances
8- Altering near-bed hydrodynamics

Question 17

Positive effects of sediment destabilisers-

Answer 17

oxygenation and habitat creation

Question 18

primary production in shallow, Coastal waters

Answer 18

high nutrients due to upwelling or riverine input
light can be a limiting factor

Question 19

energetic links between systems

Answer 19

dead organic material (Detritus, carrion,DOM, POM)
Living organic material (Advection of plankton, larval settlement, movement of adults)

Question 20

Macrophyte/macroalgae dominated systems exporters of?

Answer 20

Export POM & DOM

Question 21

Energy inputs to Sandy Beaches

Answer 21

Macrophytes
Carrion
DOM
Plant and insect litter
Episammic/ epipelic diatoms
Surf Zone diatoms

Question 22

Macrofaunal consumers

Answer 22

Filter feeders- dissipative state
surf zone zooplankton
scavengers- with macrophyte inputs

Question 23

Interstitial fauna (meiofauna)

Answer 23

Nematodes
copepods
Turbellaria
gastrotrich
ostracods
tardigrades

Question 24

sediment stabilisers

Answer 24

Epipelic algae
Episammic algae
Filamentous cyanobacteria

Question 25

Epipelic algae

Answer 25

exude EPS to migrate through sediment

(Algae that grow on inorganic or organic sediments that are smaller than most unicellular algae.)

Question 26

Episammic Algae

Answer 26

stick grains together with EPS
(Algae that grow on sand, which is hard, relatively inert, and has relatively little surface area)

Question 27

Filamentous cyanobacteria

Answer 27

form a network of sticky (EPS) threads
(diverse and morphologically complex group of prokaryotes)