Primary Producers

Primary producers are organisms with the ability to convert inorganic materials into organic materials to be used as food. They are the basis of all food webs. In the soft shore ecosystem, the flora and algae (both micro- and macroscopic) play a significant role as primary producers.

The following is a list of representative species from each group of primary producer that can be found in Hong Kong.

True Mangroves

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Kandelia obovata

Photo taken at Mai Po

by Joe Lee

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Aegiceras corniculatum

Photo taken at Mai Po

by Yan Ping Loo

Common name: river mangrove

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Avicennia marina

Photo taken at Lai Chi Wo

by Joe Lee

Common name: grey mangrove

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Bruguiera gymnorhiza

Photo taken at Lai Chi Wo

by Joe Lee

Common name: large-leafed orange mangrove, oriental mangrove

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Acanthus ilicifolius

Photo taken at Mai Po

by Yan Ping Loo

Common name: sea holly, holly mangrove

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Acrostichum aureum

Photo taken at Mai Po

by Yan Ping Loo

Common name: golden leather fern

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Lumnitzera racemosa

Photo taken by Joe Lee

Common name: white-flowered black mangrove

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Heritiera littoralis

Photo taken at Lai Chi Wo

by Joe Lee

Common name: looking-glass mangrove

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Excoecaria agallocha

Photo taken at Lai Chi Wo

by Joe Lee

Common name: blinding tree, milky mangrove

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Sonneratia spp.

Photo taken at Mai Po

by Yan Ping Loo

Common name: mangrove apple

**Invasive species


Sonneratia caseolaris and Sonneratia apetala are two invasive mangrove species that occur in the Deep Bay (aka Shenzhen Bay). They were introduced to Shenzhen as part of a project to afforest the coast of Shenzhen Bay. Their seedlings eventually spread to the Hong Kong side of the Bay, where they proliferate due to their high growth and reproduction rates.

 

Mangrove Associates

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Derris trifoliata

Photo taken at Mai Po

by Yan Ping Loo

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Cerbera manghas

Photo taken by Joe Lee

Common name: sea mango

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Talipariti tiliaceum

Photo taken by Joe Lee

Common name: sea hibiscus

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Clerodendrum inerme

Photo taken by Joe Lee

 

Saltmarsh Plants

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Suaeda australis

Photo taken at Lai Chi Wo

by Joe Lee

Common name: austral seablite

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Cyperus malaccensis

Photo taken at Mai Po

by Yan Ping Loo

Common name: short-leaved Malacca galingale

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Panicum repens

Photo taken at Lai Chi Wo

by Joe Lee

Common name: torpedograss

 

Seagrasses

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Zostera japonica

Photo taken at Lai Chi Wo

by Joe Lee

Common name: Japanese eelgrass, drawf eelgrass

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Ruppia maritima

Photo taken at Mai Po

by Yan Ping Loo

Common name: widgeon grass

 

Microalgae

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Microphytobenthos (MPB)

MPB extracted from sediment in the mangrove forest, viewed under a phase-contrast microscope at 400X.


The MPB is a major food source to grazers in both mangrove forests and tidal flats. Organisms that feed on them are such as bowed fiddler crab (Tubuca arcuata) in the mangrove forest, and great blue-spotted mudskipper (Boleophthalmus pectinirostris) on the tidal flat.

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Phytoplankton

Phytoplankton extracted from the subtidal surface water, viewed under a phase-contrast microscope at 10X.

Phytoplankton drift along with the tides, and they feed marine organisms such as greenback mullet (Planiliza subviridis) and false cockle (Anomalodiscus squamosa).

 

Macroalgae

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Ulva spp.

Photos taken by Wai Hong Yiu

Common name: green algae

Macroalgae are a diverse group of multicellular plant-like organisms. They share some physiological characteristics with plants, such as the ability to photosynthesize through light harvesting pigment, but they are not regarded as plant. They should be distinguished from seagrass, which is the flowering plant with vascular tissues for transportation of water and nutrients. Macroalgae commonly found in the marine environment are called seaweed. Some particular species of seaweed, such as the green algae (Ulva spp.), could be found at the soft bottom of estuaries. Occasionally, some brown algae (Colpomenia sinuosa) could be found in the relatively saline environment in the estuarine area.

 
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Colpomenia sinuosa

Photos taken by Wai Hong Yiu

Common name: brown algae