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Benthic Depth

Benthic depth influences exposure to air, light, temperature, pressure and wind/wave action. It is an indicator of sea floor shape, which in turn influences attributes such as energy and processes of erosion and deposition.

Bathymetric LiDAR for Sunshine Coast. Image by Queensland Government

Quick facts

Benthic depth
is the depth of the seafloor using the Australian Height Datum (AHD) and may also be referred to as absolute relief.

Queensland Intertidal and Subtidal Classification Scheme

Complex interactions between mixing and water quality parameters determine the effective euphotic depth[2]. Relevant seascape-level thresholds are:

  • intertidal
  • -10m (shallow/deep seagrass threshold)
  • -60m (limit of shelf upwellings and mixing)*
  • -30 to -150m (limits of mesophotic reefs[3])
  • -200m which marks the approximate edge of the continental shelf.

*There is also a changeover in ecological communities at 60m due to both light and nutrient availability. Above 60m photoautotrophs occur (i.e.  they create their own food using light photosynthesis. This includes plants, and animals having a symbiotic relationship with plants (e.g. zooxanthellae within corals). Below 60m heterotrophs occur ( i.e. they consume other animals and plants for food but may have some photosynthesis as well.)[1]

Benthic depth (depth of the sea floor) is a part of the 'Terrain' theme for attributes used in the Intertidal and Subtidal Classification Scheme.

Attribute category table - Benthic Depth

Community

Habitat (m)

Seascape (m)

Subregion (m)

Region (m)

25cm divisions

0-1

0 - 5

0 - 20

0m to 60m

25cm divisions

1-2

25cm divisions

2-3

50cm divisions

3-4

50cm divisions

4- 5

1m divisions

5 -10

5 - 10

1m divisions

10 - 15

10 - 15

1m divisions

15 - 20

15 - 20

.. Increment by 5m

.. Increment by 5 until 50

..Increment by 5  until 40

20 - 40

40 - 50

40 - 60

..Increment by 5m

50 - 60

50 - 60

As for Habitat

...Increment by 10 until 200

60 - 100

60 - 100

60 - 100

100 - 150

100 - 200

100 - 200

150 - 200

200 - 220

200 - 300

200 - 300

200 - 500

... Increment by 20 until 300

300 - 400

300 - 500

300 - 500

...Increment by 100 until 1000

 

500 - 700

500 - 1000

500 - 1000

700 - 1000

1000 - 1500

1000 - 1500

1000 - 1500

1000 - 1500

below 1500

below 1500

below 1500

below 1500

Additional Information


References

  1. ^ Lesser, MichaelP, Slattery, Marc, Laverick, JackH, Macartney, KeirJ & Bridge, TomC, 'Global community breaks at 60 m on mesophotic coral reefs', Global Ecology and Biogeography, vol. 0, no. 0, viewed 5 July 2019, <https://onlinelibrary.wiley.com/doi/abs/10.1111/geb.12940>.
  2. ^ McArthur, MA, Brooke, BP, Przeslawski, R, Ryan, DA, Lucieer, VL, Nichol, S, McCallum, AW, Mellin, C, Cresswell, ID & Radke, LyndaC 2010, 'On the use of abiotic surrogates to describe marine benthic biodiversity', Estuarine, Coastal and Shelf Science, vol. 88, no. 1, pp. 21-32, Elsevier.
  3. ^ Rocha, LuizA, Pinheiro, HudsonT, Shepherd, Bart, Papastamatiou, YannisP, Luiz, OsmarJ, Pyle, RichardL & Bongaerts, Pim 20 July 2018, 'Mesophotic coral ecosystems are threatened and ecologically distinct from shallow water reefs', Science, vol. 361, no. 6399, pp. 281-284, viewed 25 March 2019, <http://www.sciencemag.org/lookup/doi/10.1126/science.aaq1614>.

Last updated: 15 July 2019

This page should be cited as:

Benthic Depth, WetlandInfo 2019, Department of Environment and Science, Queensland, viewed 6 August 2019, <https://wetlandinfo.des.qld.gov.au/wetlands/ecology/aquatic-ecosystems-natural/estuarine-marine/attributes/benthic-depth/>.

Queensland Government
WetlandInfo   —   Department of Environment and Science