Life on the Continental Shelf - Marine Biology - Lecture Slides, Slides for Biology. Central University of Kerala

Biology

Description: These are the lecture slides of Marine Biology. Key important points are: Life on the Continental Shelf, Continental Shelf, Extension of the Continent, Continental Shelves, Subtidal Ecosystem, Subtidal Abiotic Factors, Subtidal Organisms, Distribution of Marine Life, Subtidal Communities, Soft Bottom Subtidal Communities
Showing pages  1  -  2  of  28
The preview of this document ends here! Please or to read the full document or to download it.
Document information
Embed this document:
PowerPoint Presentation

Life on the Continental Shelf

Docsity.com

Continental Shelf: • shallow submerged extension of

the continent

Docsity.com

THE CONTINENTAL SHELVES

• Average width – 75 km, narrower in areas with strong current;

• Average slope – 0o07’; • Average depth flattest portion– 60 m; • Average depth where greatest change

of slope – 130 m; • Hills of 20 m or more and depression

of 20 m or more

Docsity.com

(Tidal zone)

(low tide to shelf break))

Photic 100m

Docsity.com

To help protect your privacy, PowerPoint has blocked automatic download of this picture.

SUBTIDAL ECOSYSTEM

• Marine areas that are never exposed during low tide i.e. always submerged.

• Also known as the sublitoral zone

Docsity.com

SUBTIDAL ABIOTIC FACTORS • Influenced by sedimentation processes

(especially shallow areas) - lithogenic sediments (physical and chemical

weathering of rocks (turbidities, volcanic ash, red clay))

- biogenic sediments (shells and skeletons of marine organisms)

Docsity.com

SUBTIDAL ORGANISMS

Plankton (suspended in water column) • Nekton (able to swim against current)

Benthic (on/in bottom sediment) • Demersal Epifauna Infauna

Pelagic

Docsity.com

Distribution of marine life

Pelagic

Benthic

Docsity.com

SUBTIDAL COMMUNITIES

 Soft-bottom Subtidal Communities

 Hard-bottom Subtidal Communities

Docsity.com

SOFT-BOTTOM SUBTIDAL COMMUNITIES

Made up of : • Muddy substrate • Sandy substrate

Docsity.com

SOFT-BOTTOM SUBTIDAL COMMUNITIES

Influenced by: 1. Particle size distribution 2. Sediment stability 3. light 4. salinity 5. temperature

Docsity.com

CHARACTERISTICS OF SOFT- BOTTOM SUBTIDAL

COMMUNITIES

• Type of dominant substrate i.e. sand, mud etc.

• Mainly infauna, some epifauna and almost no sessile organisms

Docsity.com

SOFT-BOTTOM SUBTIDAL ORGANISMS

1. infauna – Benthic organisms that bury themselves in the

sediment 2. epifauna

– Organisms that inhabit the surface of the bottom sediment

No. of subtidal sp. > intertidal (more stable, no desiccation) Distribution of organisms influenced by particle size (mud or sand)

Docsity.com

Soft-bottom subtidal communities Epibionts

Docsity.com

Infauna: • live within the sediment, mostly soft bottom; • mostly clams and worms (polychaetes) • burrow tubes for food scavenging and oxygen

supply • Primary producers: algae, mostly benthic

diatoms and dinoflagellates • cyanobacteria mats on mudflats • mud more productive than sand • macro- and meiobenthos, often detrivores,

living of deposits from seagrasses and marshes

• birds important grazers

Soft-bottom subtidal communities

Docsity.com

Soft-bottom subtidal communities

Docsity.com

Soft-bottom subtidal communities Examples of meiofauna in sand

Docsity.com

32,000 polychaetes in sand/m2 vs 50-500 earth worms in soil/m2 Ecological Role:

• clean sediments • aerate soil

Soft bottom subtidal communities

Docsity.com

Deposit-feeders

Docsity.com

Suspension-feeders

Docsity.com

HARD-BOTTOM SUBTIDAL COMMUNITIES

• Rocky shore

• Coral reefs

• Most important organisms are the sea weeds (able to settle on rocks/hard substrate

Docsity.com

PRODUCERS • Most important communities -

seaweeds

• Strong competition

• Amount of light influence distribution of seaweeds

• Seaweeds found in these areas have higher chlorophyll concentration

Docsity.com

grazers • Invertebrates that move slowly: sea urchin,

limpets, chitons, abalone

• Algal defense against predators - By having food that are not tasty - Fast regeneration - Calcification (formation of calcium)

Docsity.com

Hard-bottom subtidal communities Generalized food web

Detritus

Docsity.com

Hard-bottom subtidal communities Examples of N. Atlantic Kelp

Docsity.com

Hard-bottom subtidal communities Geographic Distribution of Kelp

Docsity.com

Muddy shores • Deposition of silt by tide or river Temperate: intertidal- mud flat communities subtidal- muddy bottom or seagrass communities Tropic: intertidal- mangroves subtidal- muddy bottom or seagrass communities Sandy shores • Deposition of sand by wave action Temperate: intertidal- beach communities subtidal- muddy bottom or seagrass communities Tropic: intertidal- beach communities subtidal- sandy bottom or seagrass communities Rocky shores • Little deposition Temperate: intertidal- barnacles, seaweeds, mussels subtidal- kelp beds or forests Tropic: intertidal- algae and corals subtidal- coral reefs

Recap

Docsity.com

Inquiry 1. What is the sublittoral zone? 2. What is meiofauna (infauna)? 3. How do organisms survive living in a

soft bottom community? 4. What food source are soft-bottom

communities are based on? 5. Why don’t we see anemones and sea

slugs in the high tide zone?

Docsity.com

Docsity is not optimized for the browser you're using. In order to have a better experience please switch to Google Chrome, Firefox, Internet Explorer 9+ or Safari! Download Google Chrome