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

Kandelia obovata

Photo taken at Mai Po

by Joe Lee

Aegiceras corniculatum

Photo taken at Mai Po

by Yan Ping Loo

Common name: river mangrove

Avicennia marina

Photo taken at Lai Chi Wo

by Joe Lee

Common name: grey mangrove

Bruguiera gymnorhiza

Photo taken at Lai Chi Wo

by Joe Lee

Common name: large-leafed orange mangrove, oriental mangrove

Acanthus ilicifolius

Photo taken at Mai Po

by Yan Ping Loo

Common name: sea holly, holly mangrove

Acrostichum aureum

Photo taken at Mai Po

by Yan Ping Loo

Common name: golden leather fern

Lumnitzera racemosa

Photo taken by Joe Lee

Common name: white-flowered black mangrove

Heritiera littoralis

Photo taken at Lai Chi Wo

by Joe Lee

Common name: looking-glass mangrove

Excoecaria agallocha

Photo taken at Lai Chi Wo

by Joe Lee

Common name: blinding tree, milky mangrove

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

Derris trifoliata

Photo taken at Mai Po

by Yan Ping Loo

Cerbera manghas

Photo taken by Joe Lee

Common name: sea mango

Talipariti tiliaceum

Photo taken by Joe Lee

Common name: sea hibiscus

Clerodendrum inerme

Photo taken by Joe Lee

 

Saltmarsh Plants

Suaeda australis

Photo taken at Lai Chi Wo

by Joe Lee

Common name: austral seablite

Cyperus malaccensis

Photo taken at Mai Po

by Yan Ping Loo

Common name: short-leaved Malacca galingale

Panicum repens

Photo taken at Lai Chi Wo

by Joe Lee

Common name: torpedograss

 

Seagrasses

Zostera japonica

Photo taken at Lai Chi Wo

by Joe Lee

Common name: Japanese eelgrass, drawf eelgrass

Ruppia maritima

Photo taken at Mai Po

by Yan Ping Loo

Common name: widgeon grass

 

Microalgae

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.

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

Ulva spp.

Photos taken by Wai Hong Yiu

Common name: green algae

Colpomenia sinuosa

Photos taken by Wai Hong Yiu

Common name: brown 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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