Effects of hydrodynamics on mussel larvae settlement and mussel distribution - with a focus on fine-scale velocities in Port Alfred Marina, South Africa
(2020) In TVVR20/5006 VVRM05 20201Division of Water Resources Engineering
- Abstract
- Mussels, like other intertidal organisms, depend on the motion of water throughout their entire life cycle. Hydrodynamic forces are essential for the transportation and settlement of mussel larvae, as well as feeding and growth for adult mussels. In this study physical factors, such as local water velocities and wave characteristics, were measured over an eight-week period in Port Alfred Marina, on the south coast of South Africa. These measurements were paired with a biological assessment of mussel settlement and adult mussel distribution, to determine potential correlations. Due to a lack of identified settling larvae, the physical measurements were exclusively linked to the adult mussel distributions. Although not significant, the... (More)
- Mussels, like other intertidal organisms, depend on the motion of water throughout their entire life cycle. Hydrodynamic forces are essential for the transportation and settlement of mussel larvae, as well as feeding and growth for adult mussels. In this study physical factors, such as local water velocities and wave characteristics, were measured over an eight-week period in Port Alfred Marina, on the south coast of South Africa. These measurements were paired with a biological assessment of mussel settlement and adult mussel distribution, to determine potential correlations. Due to a lack of identified settling larvae, the physical measurements were exclusively linked to the adult mussel distributions. Although not significant, the results indicate that higher flow velocities were recorded at sites where no mussels were residing, suggesting that too high velocities may increase the detachment risk for both mussel larvae and adult mussels. Decreased velocities could however lead to silt depositing on the mussel populations and thereby impeding their growth. An average water velocity of 0,15 m/s was, according to measurements, the ideal velocity for mussel communities within Port Alfred Marina. The direction of flow could also have a potential effect on mussels, as a less parallel flow to the shoreline is proposed to be advantageous. Regarding ambient wave forces, the study found that a greater wave height was linked to more spatially dense mussel communities, increasing the nutrient input and larval contact with settlement sites. The results are highly uncertain, since only a limited number of sites are incorporated and other factors could interfere with the data, such as chemical cues, roughness, salinity, temperature, heavy metal concentration, parasites, predators and lack of food. (Less)
- Abstract (Uncoded languages)
- Abstract in Xhosa:
Limbaza, njengazo zonke izinto ezihlangeneyo zixhomekeke ekuhambeni kwamanzi kubo bonke ubomi bazo. Amandla e-hydrodynamic abalulekile ekuhanjisweni nasekuhluthweni kweembaza kunye nokondla nokukhula kweembaza zabantu abadala. Kuphando olwenziweyo izinto ezibonakalayo ezinje ngeendawo zokuhanjiswa kwamanzi, kunye neempawu zamaza, ezibalulwa kwisithuba seeveki ezisibhozo ePort Alfred Marina, kunxweme olusezantsi loMzantsi Afrika. La manyathelo axhonywe ngovavanyo lwezempilo lokuhlanjwa kwemisipha kunye nokululwa kwemisipha yabantu abadala, ukumisela ulungelelwaniso olunokubakho. Ngenxa yokunqongophala kokuhlawula izibungu, imilinganiselo yomzimba yayihambelana kuphela nokusasazwa kwembaza yabantu abadala. Nangona... (More) - Abstract in Xhosa:
Limbaza, njengazo zonke izinto ezihlangeneyo zixhomekeke ekuhambeni kwamanzi kubo bonke ubomi bazo. Amandla e-hydrodynamic abalulekile ekuhanjisweni nasekuhluthweni kweembaza kunye nokondla nokukhula kweembaza zabantu abadala. Kuphando olwenziweyo izinto ezibonakalayo ezinje ngeendawo zokuhanjiswa kwamanzi, kunye neempawu zamaza, ezibalulwa kwisithuba seeveki ezisibhozo ePort Alfred Marina, kunxweme olusezantsi loMzantsi Afrika. La manyathelo axhonywe ngovavanyo lwezempilo lokuhlanjwa kwemisipha kunye nokululwa kwemisipha yabantu abadala, ukumisela ulungelelwaniso olunokubakho. Ngenxa yokunqongophala kokuhlawula izibungu, imilinganiselo yomzimba yayihambelana kuphela nokusasazwa kwembaza yabantu abadala. Nangona zingabalulekanga, iziphumo zibonisa ukuba ukuhamba okuphezulu kwamanani kwiindawo apho kungekho mussels yayihlala khona. Iphakamisa ukuba imithamo ephezulu kakhulu inokunyusa umngcipheko wokubakho kwezi mbaza kunye nembaza yabantu abadala. Ukuncitshiswa kwezantya zokuhamba kungakhokelela ekubekeni isilika kubuninzi beembaza kwaye ngaloo ndlela kuthintele ukukhula kwazo. Isantya esiphakathi sokuhamba kwamanzi oku-0,15 m / s, ngokweemilinganiselo, yeyona ndawo ifanelekileyo yoluntu lwezimbaza ngaphakathi ePort Alfred Marina. Indlela yokuhambahamba inokuba nefuthe elinokwenzeka kwimbaza, njengoko ukuhamba ngokulingana okuhamba elunxwemeni kucetywayo ukuba kulunge. Ngokuphathelele kumaza, amaza uphononongo lufumanise ukuba ukuphakama kwamaza okuphezulu kunxulunyaniswa nemimandla enobuninzi bendawo ethe tyaba kwaye konyusa igalelo lesondlo kunye nokunxibelelana okuvusa imimandla kwiindawo zokuhlala. Iziphumo aziqinisekanga kakhulu, kuba kuphela inani eliqingqiweyo leziza lifakiwe kwaye ezinye izinto zinokuphazamisa uphando, enje ngeekhemikhali, uburhabaxa, ityuwa, iqondo lokutshisa, ubunzima bentsimbi, izinampuzane ezincinci, izilwanyana ezixhaphaza abanye kunye nokunqongophala kokutya. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9021870
- author
- Janson, Magnus LU
- supervisor
- organization
- course
- VVRM05 20201
- year
- 2020
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Larval settlement, hydrodynamics, water velocity, mussel distribution, Port Alfred, South Africa
- publication/series
- TVVR20/5006
- report number
- 20/5006
- ISSN
- 1101-9824
- language
- English
- additional info
- Examiner: Rolf Larsson
- id
- 9021870
- date added to LUP
- 2020-06-24 15:36:30
- date last changed
- 2020-07-07 09:35:01
@misc{9021870,
abstract = {{Mussels, like other intertidal organisms, depend on the motion of water throughout their entire life cycle. Hydrodynamic forces are essential for the transportation and settlement of mussel larvae, as well as feeding and growth for adult mussels. In this study physical factors, such as local water velocities and wave characteristics, were measured over an eight-week period in Port Alfred Marina, on the south coast of South Africa. These measurements were paired with a biological assessment of mussel settlement and adult mussel distribution, to determine potential correlations. Due to a lack of identified settling larvae, the physical measurements were exclusively linked to the adult mussel distributions. Although not significant, the results indicate that higher flow velocities were recorded at sites where no mussels were residing, suggesting that too high velocities may increase the detachment risk for both mussel larvae and adult mussels. Decreased velocities could however lead to silt depositing on the mussel populations and thereby impeding their growth. An average water velocity of 0,15 m/s was, according to measurements, the ideal velocity for mussel communities within Port Alfred Marina. The direction of flow could also have a potential effect on mussels, as a less parallel flow to the shoreline is proposed to be advantageous. Regarding ambient wave forces, the study found that a greater wave height was linked to more spatially dense mussel communities, increasing the nutrient input and larval contact with settlement sites. The results are highly uncertain, since only a limited number of sites are incorporated and other factors could interfere with the data, such as chemical cues, roughness, salinity, temperature, heavy metal concentration, parasites, predators and lack of food.}},
author = {{Janson, Magnus}},
issn = {{1101-9824}},
language = {{eng}},
note = {{Student Paper}},
series = {{TVVR20/5006}},
title = {{Effects of hydrodynamics on mussel larvae settlement and mussel distribution - with a focus on fine-scale velocities in Port Alfred Marina, South Africa}},
year = {{2020}},
}