Difference between revisions of "Functional diversity in marine ecosystems"

From Coastal Wiki
Jump to: navigation, search
 
(44 intermediate revisions by 6 users not shown)
Line 1: Line 1:
−
Functional diversity refers to the variety of biological processes, functions or characteristics of a particular ecosystem.
 
  
−
<ref> Thorne-Miller Boyce (1999) The living ocean: understanding and protecting marine biodiversity. United States of America 213p</ref>Functional diversity reflects the biological complexity of an ecosystem. Some scientists argue that examining functional diversity may in fact be the most meaningful way of assessing biodiversity while avoiding the difficult and usually impossible task of cataloging all species in marine ecosystems. By focusing on processes, it may be easier to determine how an ecosystem can most effectively be protected. Protecting biological functions will protect many of the species that perform them. However, the exact function of most of the species is hardly known to date.
+
{{ Definition| title = Functional diversity
 +
| definition = The value and range of functional traits that contribute to [[ecosystem functioning]]<ref>Reiss, J., Bridle, J.R., Montoya, J.M. and Woodward, G. 2009. Emerging horizons in biodiversity and ecosystem functioning research. Trends Ecol. Evol., 24: 505-514</ref>.<br> Functional group: Groups of species with similar ecological roles/functions.}}
  
−
<ref name="Dobson">Dobson M. and Frid C. (1998). Ecology of aquatic systems. Addison Wesley Longman Limited: Edingburgh, (England). p222</ref>There are several ways in which ecological classifications group organisms according to common functions: classification according to their habitat, to their position in the food web or to their functional feeding mechanism.
+
 
 +
 
 +
==Functional diversity==
 +
Functional diversity refers to the variety of biological processes, functions or characteristics of a particular ecosystem in this case the [[Marine Biodiversity|marine ecosystem]]. 
 +
 
 +
<ref> Thorne-Miller Boyce (1999) The living ocean: understanding and protecting marine biodiversity. United States of America 213p</ref>Functional diversity reflects the biological complexity of an ecosystem. Some scientists argue that examining functional diversity may in fact be the most meaningful way of assessing biodiversity while avoiding the difficult and usually impossible task of cataloging all species in marine ecosystems.  By focusing on processes, it may be easier to determine how an ecosystem can most effectively be protected from human disturbance.  Protecting biological functions will protect many of the species that perform them. However, the exact function of most of the species is hardly known to date.
 +
 
 +
Functional diversity increases the overall productivity of an ecosystem by allowing for an increase in niche occupation - the way a species matches the specific environmental conditions within a habitat in interaction with other species. Functional redundancy occurs when different species fulfill the same role in an ecosystem (thus filling the same functional niche); it is in some way the opposite of functional diversity. Functional redundancy contributes to ecosystem resilience. Higher species diversity can lead to an increase in overall ecosystem productivity, but does not necessarily insure the security of functional overlap. In ecosystems with high redundancy, losing a species (which lowers overall functional diversity) will not always lower overall ecosystem function due to high functional overlap.
 +
 
 +
 
 +
==Functional groups==
 +
 
 +
A functional group is a set of species that share alike characteristics within a community and therefore often share an ecological niche. Species sharing an ecological niche generally have similar structures in order to achieve the greatest amount of fitness. This refers for example to the ability to successfully create offspring, and to sustain life by avoiding predators and sharing prey.
 +
 
 +
<ref name="Dobson">Dobson M. and Frid C. (1998). Ecology of aquatic systems. Addison Wesley Longman Limited: Edingburgh, (England). p. 222</ref>There are several ways in which ecological classifications group organisms according to common functions: classification according to their habitat, to their position in the food web or to their functional feeding mechanism.
  
 
===Classification by ‘[[habitat]]’===
 
===Classification by ‘[[habitat]]’===
Line 9: Line 23:
 
Aquatic organisms can be divided into four major groups: pelagic, benthic, neuston and fringing, according to the water body which they inhabit.<ref name="Dobson">Dobson M. and Frid C. (1998). Ecology of aquatic systems. Addison Wesley Longman Limited: Edingburgh, (England). p222</ref>  
 
Aquatic organisms can be divided into four major groups: pelagic, benthic, neuston and fringing, according to the water body which they inhabit.<ref name="Dobson">Dobson M. and Frid C. (1998). Ecology of aquatic systems. Addison Wesley Longman Limited: Edingburgh, (England). p222</ref>  
  
−
PELAGIC ORGANISMS
+
Sub-categories described in the Coastal Wiki are:
 +
:[[Rocky shores]]
 +
:[[Sandy shores]]
 +
:[[Continental shelf habitat]]
 +
:[[Open oceans]]
 +
:[[Deep sea habitat]]
 +
:[[Coral reefs]]
 +
:[[Seagrass meadows]]
 +
:[[Mangroves]]
 +
:[[Salt marsh]]es
 +
:[[Estuaries]]
 +
 
 +
====Pelagic====
  
−
[[Pelagic]] organisms are those that live in ocean water (not associated with the bottom) thus in the water column and can be divided in [[plankton]] and [[nekton]].  
+
[[Pelagic]] organisms are those that live in ocean water and are not associated with the bottom. They thus inhabit the water column and can be divided into [[plankton]] and [[nekton]].  
−
Plankton are organisms that are suspended, (they float or are weakly self-propelled) in the water and drift with it as it moves. Plankton is either passive and includes algae, bacteria and variety of animals. Plankton is usually subdivided in [[phytoplankton]] (photosynthethic organisms like algae) and [[zooplankton]] (animals), what refers to their ecological function.   
+
Plankton are organisms that are suspended (they float or are weakly self-propelled) in the water and drift with it as it moves. Plankton is either passive and includes algae, bacteria and variety of animals. Plankton is usually subdivided in [[phytoplankton]] (photosynthethic organisms like algae) and [[zooplankton]] (animals), what refers to their ecological function.   
−
Plankton can also be subdivided in [[holoplankton]] and [[meroplankton]].  Holoplankton are permanent members, represented by many taxa in the sea.  Meroplankton are temporary members, spending only a part of their life cycle in the plankton. They include larvae of anemones, barnacles, crabs and even fish, which later in life will join the nekton or the benthos.  Meroplankton are very much a feature of the sea, particularly coastal waters, as the often sedentary adult forms of coastal species use their planktonic stage for dispersal.
+
Plankton can also be subdivided in [[holoplankton]] and [[meroplankton]].  Holoplankton are permanent members, represented by many taxa in the sea.  Meroplankton are temporary members, spending only a part of their life cycle as plankton. They include larvae of anemones, barnacles, crabs and even fish, which later in life will join the nekton or the benthos.  Meroplankton are very much a feature of the sea, particularly coastal waters, as the often sedentary adult forms of coastal species use their planktonic stage for dispersal.
 
Nekton are organisms swimming actively in the water, it includes a variety of animals, mostly fish.  
 
Nekton are organisms swimming actively in the water, it includes a variety of animals, mostly fish.  
  
−
BENTHIC ORGANISMS.
+
====Benthic====
  
 
Benthos comprises organisms on the bed of the water body. Animals attached to or living on the bottom are referred to as epifauna, while those which burrow into soft sediments or live in spaces between sediment particles are described as infauna.
 
Benthos comprises organisms on the bed of the water body. Animals attached to or living on the bottom are referred to as epifauna, while those which burrow into soft sediments or live in spaces between sediment particles are described as infauna.
Line 22: Line 48:
 
Attached multicellular plants and algae are referred to as macrophytes, while single-celled or filamentous algae are called as periphyton or microphytobenthos.  Epiphytic algae are those which grow on macrophytes.  Benthic consumers can be divided by size into macrofauna (>500 μm), meiofauna (10-500 μm) and micro-organisms (<10 μm).
 
Attached multicellular plants and algae are referred to as macrophytes, while single-celled or filamentous algae are called as periphyton or microphytobenthos.  Epiphytic algae are those which grow on macrophytes.  Benthic consumers can be divided by size into macrofauna (>500 μm), meiofauna (10-500 μm) and micro-organisms (<10 μm).
  
−
NEUSTON
+
====Neuston====
  
 
Neuston are those organisms associated with the water surface, where they are supported by surface tension.  Most neuston require very still water surface and is therefore very restricted in the sea.  
 
Neuston are those organisms associated with the water surface, where they are supported by surface tension.  Most neuston require very still water surface and is therefore very restricted in the sea.  
  
−
FRINGING COMMUNITIES
+
====Fringing community====
  
 
Fringing communities are floral communities that occur where the water is shallow enough for plentiful light to reach the bottom, allowing the growth of attached photosynthesisers, which may be entirely submerged or emergent into the air. Marine communities are composed mostly out of algal seaweeds.  Wetlands are composed of this type of vegetation.  
 
Fringing communities are floral communities that occur where the water is shallow enough for plentiful light to reach the bottom, allowing the growth of attached photosynthesisers, which may be entirely submerged or emergent into the air. Marine communities are composed mostly out of algal seaweeds.  Wetlands are composed of this type of vegetation.  
  
  
−
There are a lot of other habitat classifications, for example the EUNIS Habitat types classification.<ref> http://eunis.eea.europa.eu/habitats.jsp</ref>. This is a comprehensive pan-European system to facilitate the harmonized description and collection of data across Europe through the use of criteria for habitat identification; it covers all types of habitats from natural to artificial, from terrestrial to freshwater and marine.
+
There are many other habitat classifications, for example [http://eunis.eea.europa.eu/habitats.jsp the EUNIS Habitat types classification].<ref> http://eunis.eea.europa.eu/habitats.jsp</ref>. This is a comprehensive pan-European system to facilitate the harmonized description and collection of data across Europe through the use of criteria for habitat identification; it covers all types of habitats from natural to artificial, from terrestrial to freshwater and marine.
 
   
 
   
 
An example of the EUNIS habitat classification: marine habitats at level 1 is the following:
 
An example of the EUNIS habitat classification: marine habitats at level 1 is the following:
 +
:[[Littoral]] rock and other hard substrata
 +
:Littoral sediment
 +
:Infralittoral rock and other hard substrata
 +
:Circalittoral rock and other hard substrata
 +
:Sublittoral sediment
 +
:Deep-sea bed
 +
:Pelagic water column
 +
:Ice-associated marine habitats
  
−
* A1 [[Littoral]] rock and other hard substrata [[photo A1]]
+
<gallery>
−
 
+
Image:rock.jpg|'''Littoral rock and other hard substrata'''
−
* A2 Littoral sediment [[photo A2]]
+
Image:Sed.jpg|'''Littoral sediment'''
−
 
+
Image:Infra.jpg|'''Infralittoral rock and other hard substrata'''
−
* A3 Infralittoral rock and other hard substrata [[photo A3]]
+
Image:Circa.jpg|'''Circalittoral rock and other hard substrata'''
−
 
+
Image:Sub.jpg|'''Sublittoral sediment'''
−
* A4 Circalittoral rock and other hard substrata [[photo A4]]
+
Image:Deep.jpg|'''Deep-sea bed'''
−
 
+
Image:Pel.jpg|'''Pelagic water column'''
−
* A5 Sublittoral sediment [[photo A5]]
+
Image:ice.jpg|'''Ice-associated marine habitats'''
−
 
+
</gallery>
−
* A6 Deep-sea bed [[photo A6]]
 
−
 
 
−
* A7 Pelagic water column [[photo A7]]
 
−
 
 
−
* A8 Ice-associated marine habitats [[photo A8]]
 
  
 
===Classification by position in the [[food web]]===
 
===Classification by position in the [[food web]]===
Line 56: Line 85:
 
A simplified description of a food web: the phytoplankton are the primary producers and are eaten by the zooplankton (smallest floating animals). The zooplankton are eaten by small fish (sardines, herring) and small fish are eaten by larger fish. At the top of the marine food web are the large predators (tuna, seals, sea-birds and some species of whales).
 
A simplified description of a food web: the phytoplankton are the primary producers and are eaten by the zooplankton (smallest floating animals). The zooplankton are eaten by small fish (sardines, herring) and small fish are eaten by larger fish. At the top of the marine food web are the large predators (tuna, seals, sea-birds and some species of whales).
  
−
Phytoplankton, small zooplankton and large zooplankton, larger animals and top predators all interact in a marine food web. Each species eats and is eaten by several other species at different trophic levels.
+
Phytoplankton, small zooplankton and large zooplankton, larger animals and top predators all interact in a marine food web. Each species eats and is eaten by several other species at different trophic levels. The [[microbial loop]] is an important component of the marine food web.
  
 
The interactions in a food web are far more complex than the interactions in a [[food chain]]. Furthermore, the branching structure of food webs leads to fewer top predators compared with the numbers of top predators in a food chain.
 
The interactions in a food web are far more complex than the interactions in a [[food chain]]. Furthermore, the branching structure of food webs leads to fewer top predators compared with the numbers of top predators in a food chain.
  
−
[[Image:Food.jpg|center|An example of a simplified food web, which defines the various elements of such webs (‘functional groups’), the flow between them, and so-called ‘[[trophic]] levels’, which indicate the position of each functional group within the web.<ref>From "Fishing down marine food webs' as an integrative concept" by Daniel Pauly (University of British Columbia, Canada), Proceedings of the EXPO'98 Conference on Ocean Food Webs and Economic Productivity, online at the Community Research and Development Information Page</ref>|frame]]
+
[[Image:Food.jpg|center|Fig. An example of a simplified food web, which defines the various elements of such webs (‘functional groups’), the flow between them, and so-called ‘[[trophic]] levels’, which indicate the position of each functional group within the web.<ref>From "Fishing down marine food webs' as an integrative concept" by Daniel Pauly (University of British Columbia, Canada), Proceedings of the EXPO'98 Conference on Ocean Food Webs and Economic Productivity, online at the Community Research and Development Information Page</ref>|frame]]
−
 
 
−
MICROBIAL LOOP
 
−
 
 
−
<ref name="bigelow">http://www.bigelow.org</ref>In the microbial loop, bacteria consume Dissolved Organic Material (DOM) that cannot be directly ingested by larger organisms. DOM includes liquid wastes of zooplankton and cytoplasm that leaks out of phytoplankton cells. Bacteria are eaten by microflagellates. Ciliates, which are small enough to eat microflagellates, are eaten by zooplankton. Micro-flagellates and ciliates help to recycle organic matter back into the marine food web. Bacteria also help to facilitate phytoplankton growth by releasing nutrients when they absorb DOM. Viruses are the smallest and most abundant organisms in the sea, viral activity produces DOM, thus helping to drive energy cycles for ocean life.
 
−
The main difference of the microbial loop between estuarine and coastal waters is that coastal waters tend to have lower population densities of bacteria and of the organism that prey on them.
 
−
[[Image:Mol.jpg|left|frame]]
 
−
[[Image:Mal.jpg|right|source:<ref>http://www.waterencyclopedia.com/images</ref>|frame]]
 
−
 
 
−
 
 
  
 
===Classification by functional feeding mechanism===
 
===Classification by functional feeding mechanism===
  
 +
====Coastal benthos functional groups<ref name="Dobson"/>====
  
−
COASTAL BENTHOS<ref name="Dobson"/>
+
There is a classification with several functional groups for marine and coastal systems:
−
 
 
−
There is a classification with several groups for marine and coastal systems:
 
 
   
 
   
 
* grazer-scrapers feed upon attached algae
 
* grazer-scrapers feed upon attached algae
−
 
 
* scavengers eat coarse particulate organic matter (detritus retained by a 1 mm sieve)
 
* scavengers eat coarse particulate organic matter (detritus retained by a 1 mm sieve)
−
 
 
* collectors eat fine particulate organic matter (detritus passing through a 1 mm sieve but retained by 0.45 mm sieve)
 
* collectors eat fine particulate organic matter (detritus passing through a 1 mm sieve but retained by 0.45 mm sieve)
−
 
+
* suspension or filter feeders remove particles from the water column
−
* suspension or filter feeders remove particles from the watercolumn
 
−
 
 
 
* deposit feeders pick particles from the ocean bed
 
* deposit feeders pick particles from the ocean bed
−
 
 
* predators consume other living animals
 
* predators consume other living animals
−
 
 
* parasites derive their food from a living organism of another species (host), they usually live in or on the body of the host.
 
* parasites derive their food from a living organism of another species (host), they usually live in or on the body of the host.
 
   
 
   
 
In practice this distinction is very imprecise but useful as long as it is understood that they should not be too rigidly applied. The shelf bottom is occupied by diverse groups of benthic organisms that vary with changes in the bathymetry and sediment cover of the sea bed. For example gravel and coarse sand bottoms are mostly populated by filter feeders and fine sand bottoms are predominantly composed of deposit feeders.  Muddy substrates are almost exclusively inhabited by deposit and detritus feeders.  
 
In practice this distinction is very imprecise but useful as long as it is understood that they should not be too rigidly applied. The shelf bottom is occupied by diverse groups of benthic organisms that vary with changes in the bathymetry and sediment cover of the sea bed. For example gravel and coarse sand bottoms are mostly populated by filter feeders and fine sand bottoms are predominantly composed of deposit feeders.  Muddy substrates are almost exclusively inhabited by deposit and detritus feeders.  
  
−
COASTAL PELAGIC COMMUNITIES<ref name="Dobson"/>
+
====Pelagic functional groups====
  
−
In pelagic communities the classification based on feeding mechanism is less successful because consumers are opportunistic and will eat anything that is the correct size for their mouthparts to deal with.
+
In pelagic communities the classification based on feeding mechanism is less successful because consumers are opportunistic and will eat anything that is the correct size for their mouthparts.<ref name="Dobson"/>
  
 
Nekton are almost exclusively predators.  The smaller species like the zooplankton are both predators and grazers.  Plankton are therefore also classified by size, although there is again an overlap as many species will change to a larger size class as they grow older.
 
Nekton are almost exclusively predators.  The smaller species like the zooplankton are both predators and grazers.  Plankton are therefore also classified by size, although there is again an overlap as many species will change to a larger size class as they grow older.
  
−
ESTUARY<ref> Pinet, P.R. (1998). Invitation to Oceanography. Jones and Bartlett Publishers. London (UK) p508</ref><ref> Nybakken, J.W. (1988). Marine biology: an ecological approach. 2nd ed. Harper & Row: New York, p514 </ref>
 
  
−
In an estuary there is a large amount of [[detritus]]. Detritus may be consumed directly by deposit feeders or in suspension by various benthic suspension feeders
+
==Related articles==
−
Where the bottom is rocky, benthic communities are dominated by sessile filter feeders such as bivalves, sponges, barnacles, and bryozoans.  Mud and sand substrates support an epifauna and an infauna of suspension and deposit feeders.
+
:[[Measurements of biodiversity]]
−
The large numbers of suspension feeders and deposit feeders are consumed by a number of predators like fish and grow rapidly under the relatively low predation pressure there.
+
:[[Marine Biodiversity]]
  
−
WETLANDS<ref name="Dobson"/>
 
−
 
 
−
Fringe wetlands have a continuous or very frequent hydrological connection with the parent water body and are characterized by emergent vegetation.
 
−
Flood wetlands are, for most of the time, hydrologically separated from the parent water body. Wetlands are more based on detritus than on phytoplankton. A lot of organisms in wetlands live in the substrate, to overcome the problems of oxygen shortage and toxity faced by plant roots.
 
  
 +
==References==
 +
<references/>
  
 +
[[Category:Marine Biodiversity‏‎]]
 +
[[Category:Coastal and marine ecosystems]] 
  
−
==References==
 
−
<references/>
 
 
{{author
 
{{author
−
|AuthorName=Sohier, Charlotte}}
+
|AuthorID=15335
−
[[Category:Theme 7]]
+
|AuthorFullName=Sohier, Charlotte
 +
|AuthorName=Charlotte}}

Latest revision as of 11:30, 4 March 2024

Definition of Functional diversity:
The value and range of functional traits that contribute to ecosystem functioning[1].
Functional group: Groups of species with similar ecological roles/functions.
This is the common definition for Functional diversity, other definitions can be discussed in the article


Functional diversity

Functional diversity refers to the variety of biological processes, functions or characteristics of a particular ecosystem in this case the marine ecosystem.

[2]Functional diversity reflects the biological complexity of an ecosystem. Some scientists argue that examining functional diversity may in fact be the most meaningful way of assessing biodiversity while avoiding the difficult and usually impossible task of cataloging all species in marine ecosystems. By focusing on processes, it may be easier to determine how an ecosystem can most effectively be protected from human disturbance. Protecting biological functions will protect many of the species that perform them. However, the exact function of most of the species is hardly known to date.

Functional diversity increases the overall productivity of an ecosystem by allowing for an increase in niche occupation - the way a species matches the specific environmental conditions within a habitat in interaction with other species. Functional redundancy occurs when different species fulfill the same role in an ecosystem (thus filling the same functional niche); it is in some way the opposite of functional diversity. Functional redundancy contributes to ecosystem resilience. Higher species diversity can lead to an increase in overall ecosystem productivity, but does not necessarily insure the security of functional overlap. In ecosystems with high redundancy, losing a species (which lowers overall functional diversity) will not always lower overall ecosystem function due to high functional overlap.


Functional groups

A functional group is a set of species that share alike characteristics within a community and therefore often share an ecological niche. Species sharing an ecological niche generally have similar structures in order to achieve the greatest amount of fitness. This refers for example to the ability to successfully create offspring, and to sustain life by avoiding predators and sharing prey.

[3]There are several ways in which ecological classifications group organisms according to common functions: classification according to their habitat, to their position in the food web or to their functional feeding mechanism.

Classification by ‘habitat’

Aquatic organisms can be divided into four major groups: pelagic, benthic, neuston and fringing, according to the water body which they inhabit.[3]

Sub-categories described in the Coastal Wiki are:

Rocky shores
Sandy shores
Continental shelf habitat
Open oceans
Deep sea habitat
Coral reefs
Seagrass meadows
Mangroves
Salt marshes
Estuaries

Pelagic

Pelagic organisms are those that live in ocean water and are not associated with the bottom. They thus inhabit the water column and can be divided into plankton and nekton. Plankton are organisms that are suspended (they float or are weakly self-propelled) in the water and drift with it as it moves. Plankton is either passive and includes algae, bacteria and variety of animals. Plankton is usually subdivided in phytoplankton (photosynthethic organisms like algae) and zooplankton (animals), what refers to their ecological function. Plankton can also be subdivided in holoplankton and meroplankton. Holoplankton are permanent members, represented by many taxa in the sea. Meroplankton are temporary members, spending only a part of their life cycle as plankton. They include larvae of anemones, barnacles, crabs and even fish, which later in life will join the nekton or the benthos. Meroplankton are very much a feature of the sea, particularly coastal waters, as the often sedentary adult forms of coastal species use their planktonic stage for dispersal. Nekton are organisms swimming actively in the water, it includes a variety of animals, mostly fish.

Benthic

Benthos comprises organisms on the bed of the water body. Animals attached to or living on the bottom are referred to as epifauna, while those which burrow into soft sediments or live in spaces between sediment particles are described as infauna.

Fauna.jpg

Attached multicellular plants and algae are referred to as macrophytes, while single-celled or filamentous algae are called as periphyton or microphytobenthos. Epiphytic algae are those which grow on macrophytes. Benthic consumers can be divided by size into macrofauna (>500 μm), meiofauna (10-500 μm) and micro-organisms (<10 μm).

Neuston

Neuston are those organisms associated with the water surface, where they are supported by surface tension. Most neuston require very still water surface and is therefore very restricted in the sea.

Fringing community

Fringing communities are floral communities that occur where the water is shallow enough for plentiful light to reach the bottom, allowing the growth of attached photosynthesisers, which may be entirely submerged or emergent into the air. Marine communities are composed mostly out of algal seaweeds. Wetlands are composed of this type of vegetation.


There are many other habitat classifications, for example the EUNIS Habitat types classification.[4]. This is a comprehensive pan-European system to facilitate the harmonized description and collection of data across Europe through the use of criteria for habitat identification; it covers all types of habitats from natural to artificial, from terrestrial to freshwater and marine.

An example of the EUNIS habitat classification: marine habitats at level 1 is the following:

Littoral rock and other hard substrata
Littoral sediment
Infralittoral rock and other hard substrata
Circalittoral rock and other hard substrata
Sublittoral sediment
Deep-sea bed
Pelagic water column
Ice-associated marine habitats

  • Littoral rock and other hard substrata

  • Littoral sediment

  • Infralittoral rock and other hard substrata

  • Circalittoral rock and other hard substrata

  • Sublittoral sediment

  • Deep-sea bed

  • Pelagic water column

  • Ice-associated marine habitats

Classification by position in the food web

[5]It is very difficult to make generalizations about the trophic relationships in coastal marine systems, because the ecological habitats are so diverse. A simplified description of a food web: the phytoplankton are the primary producers and are eaten by the zooplankton (smallest floating animals). The zooplankton are eaten by small fish (sardines, herring) and small fish are eaten by larger fish. At the top of the marine food web are the large predators (tuna, seals, sea-birds and some species of whales).

Phytoplankton, small zooplankton and large zooplankton, larger animals and top predators all interact in a marine food web. Each species eats and is eaten by several other species at different trophic levels. The microbial loop is an important component of the marine food web.

The interactions in a food web are far more complex than the interactions in a food chain. Furthermore, the branching structure of food webs leads to fewer top predators compared with the numbers of top predators in a food chain.

Fig. An example of a simplified food web, which defines the various elements of such webs (‘functional groups’), the flow between them, and so-called ‘trophic levels’, which indicate the position of each functional group within the web.[6]

Classification by functional feeding mechanism

Coastal benthos functional groups[3]

There is a classification with several functional groups for marine and coastal systems:

  • grazer-scrapers feed upon attached algae
  • scavengers eat coarse particulate organic matter (detritus retained by a 1 mm sieve)
  • collectors eat fine particulate organic matter (detritus passing through a 1 mm sieve but retained by 0.45 mm sieve)
  • suspension or filter feeders remove particles from the water column
  • deposit feeders pick particles from the ocean bed
  • predators consume other living animals
  • parasites derive their food from a living organism of another species (host), they usually live in or on the body of the host.

In practice this distinction is very imprecise but useful as long as it is understood that they should not be too rigidly applied. The shelf bottom is occupied by diverse groups of benthic organisms that vary with changes in the bathymetry and sediment cover of the sea bed. For example gravel and coarse sand bottoms are mostly populated by filter feeders and fine sand bottoms are predominantly composed of deposit feeders. Muddy substrates are almost exclusively inhabited by deposit and detritus feeders.

Pelagic functional groups

In pelagic communities the classification based on feeding mechanism is less successful because consumers are opportunistic and will eat anything that is the correct size for their mouthparts.[3]

Nekton are almost exclusively predators. The smaller species like the zooplankton are both predators and grazers. Plankton are therefore also classified by size, although there is again an overlap as many species will change to a larger size class as they grow older.


Related articles

Measurements of biodiversity
Marine Biodiversity


References

  1. ↑ Reiss, J., Bridle, J.R., Montoya, J.M. and Woodward, G. 2009. Emerging horizons in biodiversity and ecosystem functioning research. Trends Ecol. Evol., 24: 505-514
  2. ↑ Thorne-Miller Boyce (1999) The living ocean: understanding and protecting marine biodiversity. United States of America 213p
  3. ↑ 3.0 3.1 3.2 3.3 Dobson M. and Frid C. (1998). Ecology of aquatic systems. Addison Wesley Longman Limited: Edingburgh, (England). p. 222 Cite error: Invalid <ref> tag; name "Dobson" defined multiple times with different content
  4. ↑ http://eunis.eea.europa.eu/habitats.jsp
  5. ↑ http://oceanworld.tamu.edu
  6. ↑ From "Fishing down marine food webs' as an integrative concept" by Daniel Pauly (University of British Columbia, Canada), Proceedings of the EXPO'98 Conference on Ocean Food Webs and Economic Productivity, online at the Community Research and Development Information Page
The main author of this article is Sohier, Charlotte
Please note that others may also have edited the contents of this article.
Citation: Sohier, Charlotte (2024): Functional diversity in marine ecosystems. Available from http://www.coastalwiki.org/wiki/Functional_diversity_in_marine_ecosystems [accessed on 21-11-2024]
Retrieved from "https://www.coastalwiki.org/w/index.php?title=Functional_diversity_in_marine_ecosystems&oldid=80913"