Journal of Agricultural Science; Vol. 6, No. 6; 2014 ISSN 1916-9752 E-ISSN 1916-9760 Published by Canadian Center of Science and Education

Properties of the Mangrove Community Sediment on the Island of El Souda Western Saudi Arabia Ebtisam Hassan Awari1 & Amal Mohamed Jan Mullah1 1

Department of Geography and Geographic Information system, Faculty of Arts & Humanities, King Abdulaziz University, Jeddah, Saudi Arabia Correspondence: Ebtisam Hassan Awari, Department of Geography and Geographic Information system, Faculty of Arts & Humanities, King Abdulaziz University, Jeddah, Saudi Arabia. E-mail: [email protected]

Received: March 17, 2014 doi:10.5539/jas.v6n6p165

Accepted: April 21, 2014

Online Published: May 15, 2014

URL: http://dx.doi.org/10.5539/jas.v6n6p165

Abstract Blue carbon refers to the carbon captured by oceans and coastal ecosystems. The carbon captured by living organisms in oceans is stored in the form of biomass and sediments. Blue carbon is considered to be a modern trend to reduce emissions of carbon dioxide in the atmosphere and mitigate climate change. The aim was to understand the characteristics and nature of this ecosystem. Data on various parameters including sediment hydro chemical properties, vital nutrients and organic matter were determined across eight different sectors that were divided on the basis of age and density of mangrove forest. The study showed that sectors in the studied mangrove forest of El-Souda–West Island Kingdom of Saudi Arabia with older and denser trees gave more significant information on hydro chemical properties than sectors with younger trees. Weak relationship was found between the degree of alkalinity and the growth of mangroves. The distribution of dissolved oxygen values was irregular between the sectors. The results of vital nutrients showed that the highest values of nitrates were recorded in sector 7 and 8. Absence of organic pollution in the study area that was attributed to organic rich sediment that gets accumulated in the mangrove roots. In general the values of vital nutrients below the international limit. A strong relationship was observed between the organic content of the sediment (organic carbon oxidized, organic carbon, total, organic matter), and the density of mangroves. The study revealed the role of benthic organisms especially cancers in enriching the sediment organic matter beside the impact of the tide, and the nature of the soil, and the proximity and distance from the sea. Keywords: biodiversity, blue carbon, El-Souda, mangrove communities, Red Sea Coast, Saudi Arabia 1. Introduction Carbon Blue or what is known as Blue Carbon represents one of modern ideas to reduce emissions of carbon dioxide CO2 in the atmosphere, thus limit climate change (Sedjo & Sohngen, 2012). This emphasizes the need to maintain reservoirs of organic carbon reduced in the sediments of wet lands environments whether mangrove forests or salt marshes or sea grass. All these have the ability to capture, store and sequestering carbon dioxide in the sediments for hundreds or even thousands of years (Tripati et al., 2009). This is an extraordinary repository of carbon in the world. Today mangrove forests represent the largest sinks of carbon in the world where store carbon 15-times more than the rest of the wet land and absorbed it for thousands of years (Margareth, 2011). However, recent studies have proven the retreat of mangrove forests by up to 35% of the total area of mangrove in the world (Rezende et al., 2006). Where Margareth (2011) estimated rate of decline in the range of 30% -50% over the last fifty years and Daniel et al. (2012) recorded a reduction of 10% -15% of the total volume of the world's mangrove forests. Mangrove forests are hot spots for biodiversity, they provide important and valuable ecosystem functions, including a large carbon sink capacity (Duarte et al., 2008; Duarte, 2009). Nelleman et al. (2009) reported that mangrove trees have the highest productivity of any forest ecosystem, but this tree (and the other blue carbon habitats) are being rapidly destroyed at a higher rate than tropical forests ecosystem, but this tree (and the other blue carbon habitats) are being rapidly destroyed at a higher rate than tropical forests (Spalding et al., 2010). Albert et al. (2012) indicated that in areas of high use and high population density, the cutting of mangroves causes a substantial loss of carbon from the aboveground biomass component. Therefore, maintain mangroves, and restoring growth is very important for its effectiveness in shorthand, and store and sequesters carbon in the form of deposits which will reduce the effects of climate change in the globe. This study was assigned in order to shed light on the properties of sediments member of the community mangrove on the island of Souda west of Saudi Arabia as 165

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a case studdy. The aim was to understannd the characteeristics and naature of this ecosystem with a high potentia al for interactionn with the natuural environmental conditions, and the abiliity to interact w with low humaan interference e. 2. Materiaals and Methoods 2.1 Study A Area The islandd of El-Souda western w Saudi A Arabia is locatted on the Red Sea coast (souuth of the city oof Jeddah) betw ween latitudes 220º 34′ 48″ - 20º 2 35′ 24″ andd longitudes 399º 34′ 12″ - 39ºº 37′ 48″ (Figgure 1). The cooast area consissts of bays proteected surroundded peninsula ffrom the northh and south foorming a peninnsula known locally as El-S Souda island. Thiis made an areea protected frrom the wavess which alloweed the growth of mangrovess in these coassts. It consist of sandy beachess punctuated bby a number off bogs salt flatt surface, and exposed to waater immersion n tide making it cconnected withh the sea in thee case of high tide. The sand ccovering remaiining parts of tthe coastal plaiin, mixed in soome locations w with gravel andd limestone or coral in other arreas which maakes the appeaarance of the ccoastal plain saandy reg, exceept for areas thhat hurt the va alleys coming froom Mount Sitaa and the Valleey Dam. The ssoil in the studyy area consist of a mixture oof soils crude sandy s desert sandd torripsammeents form beachh dominant feaature of her, annd soils raw saand wet udipsaamments westw ward, and soil eppidural normal saline Solorthhids (Map Geneeral of the soil,, scale 1: 250.0000, 1986), esppecially in the areas of bogs. Thhe study field showed s that sooil texture rangging from silt C Celtic to silt sanndy by proxim mity and distanc ce on the scope oof mangroves in general.

Figure 1. Loocation of the sstudy area of E El-Souda – Weest Island Kinggdom of Saudi Arabia 2.2 Field D Data Processinng To achievve the objectivves of this sttudy, the research was desiigned on seveeral phases, w which includes the monitoringg of all environnmental phenoomena of the sttudy area, whetther literary suurvey data and field survey, which w divided intto several stagges:

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1. A prelim minary field survey was maade to the studdy area, in which the forest site was dividded into (8) se ectors preview. T These sectors where delineeated on the bbasis of the vvariation betweeen the differrent sites. The e site descriptionn representing the eight sectoors was shownn in Figure 2.

8 4

7

3

6

2 5

1

Figure 2. S Site preview seegments in the study area shoowing the eighht observation ssectors of El-S Souda – West Island Kingdom m of Saudi Araabia ne on 2. The dataa were collecteed across the eight sectors duuring three visiits to the field. First data colllection was don 14/02/20133, on which 322 soil samples were collectedd devoted to thhe measuremennt of the physiccal properties of o the soil. The second was on 25/04/2013, with 16 w water samples were collecteed to measurre Hydro chem mical characterisstics of the maangrove enviroonment. The tthird was on 223/7/2013, witth 24 samples were collected for organic deeposits in the various v sectors of the preview w devoted to thhe measuremennt of organic ccarbon. 3. Sedimeent samples weere analyzed aaccording to ((Walkley & B Black, 1934) inn a laboratoryy soil stage off data processingg. whereas maaps and satelliite images weere processed through the aanalysis of vissual space sattellite American (IKONS) for the year 20122, especially w when studying the sites of m mangroves, andd intervention sites human in tthe region. 4. The im mplementation phase of operrations classifiication and staatistical study of the relatioonship between n the variables. 3. Results and Discussion 3.1 Hydro Chemical Prooperties of the Water Mangroove communityy in El-Souda IIsland The results in (Table 1) reflected the values of hydrro chemical inndicators of waater mangrovee community in the study area and it can be concluded c thatt: pH values in the side of alkali ranged bbetween 8.05 - 8.29 (Figure 33). This indicaates the presencce of some alk kaline salts, whicch are mostly salts of calcium m carbonate. W Where the sectorr 8 recorded loower ratio (8.055), and is due to t the increase inn the amount of o organic wasste falling from m mangrove pllants. This wass in agreementt with the results of (Marchandd et al., 2011).

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The rates oof salinity valuues in the prevview segmentss ranged betweeen 40.97% - 442.58%. Sectoors 5 and 7, had the highest vallues, but mostlly similar to cooncentrations oof salinity in thhe waters of the Red Sea. Hoowever comparred to the global average of 32 to 37% salinityy, it was higheer. This may bee attributed to tthe outskirts off coastal salt marsh, m which mayy affect the inccreasing salinitty of the waterr during the tsuunami. The average vallues (± SD) off the properties Hydro chemiccal mangrove ccommunity waater in eight se ectors Table 1. T of El-Soudda – West Islannd Kingdom of Saudi Arabiaa Property

Unit

Sector 1

Sectorr 2

Sector 3

Sector 4

Sector 5

Sector 6

Sector 7

Sector 8

pH

--

8.177 ±0.41

8.11±00.38

8.19±0.433

8.08±0.40

8.16±0.41

8.20±0.46

8.112±0.41

8.05± ±0.39

Salinity

%

41.001±4.87

41.01± ±4.96

40.99±4.008

41.01±4.92

40.97±4.10

41.02±4.51

42.58±4.26

41.08 8±3.69

Alkaline (CaCO3)

mg/l

1455±15.95

160±19.2

150±15.33

150±18.6

135±13.77

140±17.36

215±27.09

150±15.32

Dissolved Oxygen (DO O)

mg/l

3.155±0.28

3.15±00.26

5.50±0.51

5.15±0.46

6.15±0.52

6.05±0.57

6.220±0.56

±0.51 6.20±

mg/l

>5±±0.65

>5±0.63

>5±0.56

>5±0.54

>5±0.50

>5±0.51

>55±0.53

>5±00.52

mg/l

>155±0.176

>15±00.174

>15±0.1668

>15±0.160

>15±0.162

>15±0.154

>115±0.153

>15±±0.155

3

4

Biochemicall oxygen requirement (BOD) chemical oxygen requirement (COD)

8.25 8.20 8.15

pH

8.10 8.05 8.00 7.95 1

2

5

6

7

8

Secto ors preview Figure 33. The pH valuues in eight secctors of the preeview of El-Soouda – West Islland Kingdom m of Saudi Arab bia The proportion of alkalinne (CaCO3) rannged from of 135 mg /l to 2200 mg/l. Sector 7 recorded thee highest values due to the natuure of the limesstone rocks thaat underlie the sector.

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Figure 4. Salinity aveerages in eight sectors of prevview of El-Souuda – West Island Kingdom of Saudi Arabia No strong links betweenn the degree oof alkaline and mangrove trrees grow wass found in thiis study and th his is contrary too what is statedd in the study oof Pablo and L Leonor (2006).. The study indicated that the informatioon on hydro cheemical be moree pronounced iin sectors preview with oldesst and most dense trees such as Sector 7 andd 8. While the young sectorss like Sector 5 don’t give cllear informatio on on hydro chem mical and exisstence of a anyy relationship between the pproperties of w water hydro chemical, and am mong mangrovess. This is consistent with thee study of Marcchand et al. (2011), which inndicate that thee young mangrroves do not give evidence cleear geochemisttry informationn like mangrovve elderly whoo usually accom mpanied by a lot l of organic deebris, and decreease the amounnt of pH. The resultss showed that the t distributionn of values of dissolved oxyggen (DO) irreggular between sectors of the study s area, rangiing from 3.155 mg/l to 6.20 mg/l. Sectorss 7 and 8 recoorded the highhest values duee to the activity of photosynthhesis, and highh turbidity of thhe water. The poor dissolvedd oxygen DO w was found in ssector 1 and 2. This may be duue to the sang region benthic animals, esppecially cancerrs and frequennt respiratory rroots in additio on to water depth (F shallower w Figure 7). In adddition to the prroximity of both the open seaa reduced the aamount of disso olved oxygen. Thhis is in agreem ment with the sstudy of Marchhand et al. (2011), who referrs to the role off benthic organ nisms in the oxyggen consumptiion and increasse the organic load.

250 CaCO3 mg / L

200 150 100 50 0 1

2

3

4 5 Secctors preview

6

7

8

Averages degreee of alkaline C CaCO3 (mg/l) in eight sectorrs preview of E El-Souda – Weest Island King gdom Figure 5. A of S Saudi Arabia

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7.00 6.00 ((DO)) mg g/L

5.00 4.00 3.00 2.00 1.00 0.00 1

2

3

4

5

6

7

8

Sectorrs preview Figure 6.. Dissolved oxxygen (DO) in eight sectors oof the preview of El-Souda – West Island K Kingdom of Sa audi Arabia

o Figuree 7. Shallower depth of waterr and frequent respiratory beenthic fauna roots in the sectoor "(1 and 2) of El-Souda––West Island Kingdom K of Saaudi Arabia. (aa: respiratory rooots; b:Organiic sediment carrbon & c:: min neral nutrition oof respiratory rroots) Needing chemiical oxygen COD is less than the The results of the index Needing biochhemical oxygeen BOD, and N es