''Halodule uninervis'' is a species of
seagrass
Seagrasses are the only flowering plants which grow in marine environments. There are about 60 species of fully marine seagrasses which belong to four families (Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae), all in the or ...
in the family
Cymodoceaceae
Cymodoceaceae is a family of flowering plants, sometimes known as the "manatee-grass family", which includes only marine species.
The 2016 APG IV does recognize Cymodoceaceae and places it in the order Alismatales, in the clade monocots. The fam ...
.
[ It is native to the western ]Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...
and Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...
s. Common names include narrowleaf seagrass in English
English usually refers to:
* English language
* English people
English may also refer to:
Peoples, culture, and language
* ''English'', an adjective for something of, from, or related to England
** English national ide ...
and ''a'shab bahriya'' in Arabic
Arabic (, ' ; , ' or ) is a Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C. E.Watson; Walter ...
.[Guiry, M. D. & G. M. Guiry. 2013]
''Halodule uninervis'' (Forsskål) Ascherson.
AlgaeBase. National University of Ireland, Galway. Accessed 28 June 2013.
Distribution and habitat
This is a common plant of the sublittoral zone in its range, growing in depths up to 20 meters in lagoon
A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') ...
s, on reef
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock o ...
s, and in many other types of marine habitat just offshore. It is known from Asian waters along the coasts of Japan, China, Vietnam
Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...
, Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
, and other nations. It occurs on Pacific Islands such as Fiji. It occurs along the Australian Pacific coast, including the Great Barrier Reef
The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, ...
. It can be found along Indian Ocean coastal regions from Australia to India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
to eastern Africa. It is resident in the Red Sea
The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; ...
and Persian Gulf
The Persian Gulf ( fa, خلیج فارس, translit=xalij-e fârs, lit=Gulf of Fars, ), sometimes called the ( ar, اَلْخَلِيْجُ ٱلْعَرَبِيُّ, Al-Khalīj al-ˁArabī), is a mediterranean sea in Western Asia. The bod ...
.
Description
This species is a flowering plant spreading via a branching rhizome that roots at the nodes. It produces erect stems and alternately arranged leaves. The narrow, toothed leaf blades are up to 15 centimeters long and usually roughly a millimeter wide,[''Halodule uninervis''.]
Flora of China. though leaf width is variable and can be up to 7 millimeters. Each leaf has a sturdy sheath up to 3.5 centimeters long. The tip of the leaf blade has three teeth.[''Halodule uninervis''.]
New South Wales Flora Online. National Herbarium, Royal Botanic Garden, Sydney. Plants of this family are dioecious. The male flower is borne on a short peduncle and is enclosed in a leaf.[ The tiny anthers are red.][ The fruit is about 2 millimeters long.][
Leaf ]morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
* Morphology (archaeology), study of the shapes or forms of artifacts
* Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...
changes according to habitat type. The leaves are wider in deeper waters. There are apparently two morphs, a narrow leaf and a wide leaf, rather than a continuous range. The narrow leaf type is found closer to shore where it is exposed more often. The wide leaf type is found in deeper areas with cloudier waters. Plants that receive less light may need more leaf blade area to perform enough photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...
.[Hedge, S., et al. (2009)]
Temporal and spatial morphological variability of the seagrasses ''Halophila ovalis'' and ''Halodule uninervis'' throughout the Great Barrier Reef region: Preliminary analysis.
Report to the Marine and Tropical Sciences Research Facility, Department of the Environment, Water, Heritage and the Arts. Reef and Rainforest Research Centre Limited, Cairns.
Biology
This grass forms dense carpets or meadows on the substrate, sometimes mixing with other seagrasses and algaes.
It occupies the lower intertidal zone, and it is less tolerant of exposure to air than are plants of the upper intertidal zone such as ''Thalassia hemprichii
''Thalassia hemprichii'', called Pacific turtlegrass, is a widespread species of seagrass in the genus '' Thalassia'', native to the shores of the Indian Ocean, the Red Sea, and the western Pacific Ocean. Its growth rate increases with CO2 enrich ...
''. It desiccates quickly. It is also sensitive to ultraviolet radiation
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
. These factors restrict it to deeper intertidal waters than some other plants.[Lan, C. Y., et al. (2005)]
Measurement of chlorophyll fluorescence reveals mechanisms for habitat niche separation of the intertidal seagrasses ''Thalassia hemprichii'' and ''Halodule uninervis''.
''Marine Biology'' 148(1) 25-34.
It is a euryhaline species, tolerating a wide salinity range.[Bensam, P. and T. R. Udhayashankar]
Colonisation and growth of the sea grasses, ''Halodule uninervis'' (Forskal) Ascherson and ''Halophila ovalis'' (R. Brown) Hooker f. in marine culture ponds at Mandapam.
The Second Indian Fisheries Forum Proceedings. Mangalore, India. May 27–31, 1990. 51-53.
Ecology
This species is an important food for the dugong
The dugong (; ''Dugong dugon'') is a marine mammal. It is one of four living species of the order Sirenia, which also includes three species of manatees. It is the only living representative of the once-diverse family Dugongidae; its closest m ...
.[Lipkin, Y. (1975)]
Food of the Red Sea dugong (Mammalia: Sirenia) from Sinai.
''Israel Journal of Zoology'' 24(3-4) 81-98. The grass grows in the Masirah Channel, a waterway between Masirah Island
Masirah Island ( ar, جَزِيْرَة مَصِيْرَة, Jazīrat Maṣīrah), also referred to as Mazeira Island or ''Wilāyat Maṣīrah'' ( ar, وِلَايَة مَصِيْرَة), is an island off the east coast of mainland Oman in the ...
and mainland Oman
Oman ( ; ar, عُمَان ' ), officially the Sultanate of Oman ( ar, سلْطنةُ عُمان ), is an Arabian country located in southwestern Asia. It is situated on the southeastern coast of the Arabian Peninsula, and spans the mouth of ...
, where it is an important food for the green sea turtle.[Jupp, B. P., et al. (1996)]
Distribution, abundance, and species composition of seagrasses at several sites in Oman.
''Aquatic Botany'' 53(3) 199-213.
This is a pioneer species
Pioneer species are hardy species that are the first to colonize barren environments or previously biodiverse steady-state ecosystems that have been disrupted, such as by wildfire.
Pioneer flora
Some lichens grow on rocks without soil, so ...
. It has been observed on high-sediment, rapidly evolving substrates in Australia and Indonesia.
This species is known to be hybridized to ''Halodule'' ''pinifolia'' in Okinawa, Japan.[Ito, Y., and Nr. Tanaka (2011]
Hybridisation in a tropical seagrass genus, Halodule (Cymodoceaceae), inferred from plastid and nuclear DNA phylogenies
. Telopea 13: 219-231.
Conservation
This plant is widely distributed and it is common throughout its range. In general its populations are stable, though it may be decreasing in localized areas, such as the coast of Bangladesh
Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...
, and it fluctuates in some Australian waters. It is affected by some degradation of habitat by forces such as coastal development, siltation
Siltation, is water pollution caused by particulate Terrestrial ecoregion, terrestrial Clastic rock, clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the ...
, sedimentation
Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the ...
, weather events and tidal action, predation, parasites, disease, trawling
Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different spec ...
and other fishing practices, dredging, pollution
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...
, eutrophication
Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytopla ...
, and climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
.
Conservation plans are in effect in various regions. Populations are monitored in the United Arab Emirates
The United Arab Emirates (UAE; ar, اَلْإِمَارَات الْعَرَبِيَة الْمُتَحِدَة ), or simply the Emirates ( ar, الِْإمَارَات ), is a country in Western Asia ( The Middle East). It is located at t ...
. It grows within the bounds of several marine parks and reserves in Africa. Populations can be disturbed only with permits in parts of Australia. Large beds are protected in Hat Chao Mai National Park in Thailand
Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...
.
References
External links
*WoRMS. (2013)
''Halodule uninervis'' (Forsskål) Ascherson, 1882.
In: Guiry, M. D. & G. M. Guiry. AlgaeBase. National University of Ireland, Galway. World Register of Marine Species. Accessed 28 June 2013.
{{Taxonbar, from=Q10880391
Cymodoceaceae
Biota of the Indian Ocean
Biota of the Pacific Ocean
Taxa named by Pierre Edmond Boissier
Taxa named by Peter Forsskål