Lecture 4 - Secondary Production Flashcards
Give the 8 groups of marine invertebrates.
- Porifera
- Cnidaria
- Ctenophora
- Polychaeta
- Mollusca
- Echinodermata
- Crustaceans
- Hemichordata
What is secondary production?
The production of biomass by all heterotrophs.
Give the two components of secondary production.
- Somatic; gaining weight, the production of tissues.
- Gonad; the production of reproductive tissue such as sperm or eggs.
Give the four food web functional groups in order.
1) Primary producers
2) Grazers
3) Suspension feeders
4) Predators
Where are grazers most likely seen?
In benthic environments
What are suspension feeders?
Organisms that collect particulate matter.
What are suspension feeders on the same trophic level as?
Grazers
Who showed that marine food webs are very complex networks, with many more connections than freshwater or terrestrial systems?
Link et al (2002)
Who came up with a definition for functional trophic levels?
Pauly and Palomares (2005)
Give three ecosystems where sea urchins can be found.
- Rocky shores
- Kelp forests
- Tropical reefs
How do sea urchins feed?
Using Aristotle’s lantern, 5 bony teeth, to scrape algae from rocks.
Give an example of how sea urchins can change an ecosystem.
Monterey Bay, California - sea otters hunted and could not eat sea urchins, so sea urchins decimated the kelp forest.
What can be the result of no sea urchins?
Give an example.
Algae overgrows other species due to lack of grazing.
Example: Caribbean 1983, urchins wiped out by disease. Algae overgrew coral reefs, leading to algal-dominated reefs.
What is Patella vulgata?
The common limpet
Describe how Patella vulgata feeds.
By scraping algae off of rocks using a radula.
What is the strongest biological material ever tested?
Limpet teeth
What are limpet teeth composed of?
Geophyte
What is special about the radula for each group?
Each group of gastropods (slugs and snails) has its own specialised form of radula depending on its specific feeding mechanisms.
Name and describe the radula structure found in limpets.
Docoglossan.
Teeth stick up.
Name and describe the radula structure found in whelks.
Stenoglossan.
An adapted form of radula alike a harpoon that injects poison.
What is the meaning of the word zooplankton?
Animal drifter
Give the size of micro-zooplankton.
20-200 micrometers
Why are micro-zooplanktons such an understudied group?
Sampling nets destroy them.
Give some examples of micro-zooplankton.
1) Phagotrophic protists, e.g. flagellates, dinoflagellates, ciliates, radiolarians, foraminiferans.
2) Metazoans, e.g. copepod nauplii, rotifers and meroplanktonic larvae.
What are copepods?
Pelagic grazers from the sub-phylum Crustacean.
What two organisms are likely to be the biggest group of organisms on the planet.
Either
- Copepods
- Krill
How big are the largest copepods? Where are they found?
7mm.
Found in the Arctic.
How large is the average copepod?
1-2mm
What is likely to be the biggest contributor to secondary production in the world?
Copepods
What is the biggest Genus of copepod?
Calinus
What is diel vertical migration?
Zooplankton species migrate away from food-rich surface waters during the day to avoid visual predators, then swim to the surface at night.
Why is diel vertical migration of zooplankton so important?
They do most of their defecating in deeper waters, shunting carbon 100s of metres below the surface, then surface waters can take up more carbon.
Describe pteropods.
Pelagic grazers that feed by forming mucus webs, entangling planktonic food.
Why are pteropods under threat currently?
Due to ocean acidification.
Vulnerable to changes in aragonite saturation state.
Classify krill.
Small crustaceans, from the order Euphausiacea
What is the estimated biomass of drill in the Southern Ocean?
500 million tonnes
What do krill eat?
- Phytoplankton
- Copepods
How do krill feed?
Using comb-like appendages on their legs
Classify bivalves.
Phylum Mollusca, Class Bivalvia
What organisms are bivalves?
Mussels, oysters, cockles
What are the only molluscs without a radula?
Bivalves
How do bivalves feed?
Suspension feeding - suck water in and pass it over their gills, extracting particles using labial pulps over the gill structure.
What are bivalves important in?
Benthic-pelagic coupling. Links the two environments, as it can draw food down from the water column above to the benthic environment.
What is pseudofaeces?
Formed when a suspension feeder rejects particles that have not yet gone through the digestive system.
Classify barnacles.
Sub-phylum crustaceans, class Maxillopoda, Infraclass Cirripedia
Describe barnacles.
- Filter feeders
- Wave ‘legs’, called cirri, in air
- Plates on upper surface open to allow cirri to come out
Classify sessile polychaetes.
Phylum Annelida, Class Polychaeta
Describe sessile polychaetes.
Stuck to rocks, use feathery appendages to capture particles in seawater.
Have chaetae, modified bristles, in each segment.
Can regrow tails.
Give and describe two sessile polychaetes.
- Spirobranchius (christmas tree worm); captures particles from water and draws down to the gut.
- Lugworm; alike an Earthworm, lives in the sand. Feeds on detritus and converts it to more complex forms of carbon.
What is detritus?
The remains of dead plants, animals or decal pellets colonised by bacteria.
Give an important deposit feeder in tropical environments.
Sea cucumbers
Describe deposit wedding by lugworms.
- Lives in a burrow
- Draws current in from one end by pumping its body
- Water and sand moves together, drawing water over gills and ingesting sand.
- Digest organic material such as microorganisms and detritus present in sediment, using strong gut enzymes that strip organic matter off of the sand.
Describe Bobbit worms.
Benthic predators. Polychaetes. Omnivorous. Launch themselves out of sediment and consume anything above them. Can grow up to 3m long.
The more links in the food web…
The less energy available to support top predators.
Give the range of energy transfer that varies with species.
10%-60%
What can be used to measure secondary production?
- A production/biomass ratio
- Stable isotope (carbon and nitrogen) analysis
In what kind of organisms is production/biomass ratio higher?
In small organisms
