|
|
|
The endemic species, Bembicium auratum
|
|
Samantha Kingston 2015
|
|
|
|
Summary | |
Throughout the intertidal and coastal areas of Australia is home to a species of a small inter tidal snail called Bembicium Auratum. They are commonly known as Gold-mouthed Periwinkle or Gold mouthed Conniwink. Endemic to Australia, their preferential habitat is mangroves or rocky shorelines due to the availability of their food source, Algae. Completely herbivorous they share the dominate characteristics of all mollusc which is the radula. As previously stated they are extremely small ranging in sizes from 17 to 27mm in height and their shell is broken up into many whorls which differentiate them from their other relative species. Their shell is brown to black and their soft body is a green to brown. Sexual dimorphic with the females being larger than the males, they produce pelagic planktotrophic veligers which are released during high tides. Currently there is no real understanding for when torsion and coiling occurs (Larval and Adult stage), which is the twisting of their body where the anus is moved above the head. Complex internal systems (nervous, circulatory, excretory and respiration) are present in larval and adult stages. In terms of their phylogenetic tree they are found in the Phylum Mollusca and the Class Gastropoda. Due to the current climate state and the increase in population on the Australia coastline B.auratum, is currently being studied for its response in this increase. They are currently being used as biomarkers to understand the increase of pollutants on the coastline.
|
 |
| Figure 1 |
|
 |
| Figure 2 |
|
|
|
Physical Description | |
The family Littorinidae share the common characteristic of having a spiral shell that is small and round. The defining characteristic of genus’s and species differs greatly on their amount of ridges found on their shell as well as the presence of the umbilicus. In specific to B.auratum, the general physical characteristics of these individuals including a: shell approximately 7 to 11 spiral grooves, Columella is smooth and the outer lip of the shell is thin in adults. The colouration of their shell ranges from white to brown however there can be brownish black depending on their environment (Quoy & Gaimard, 1834). Bembicium auratum are small inter-tidal snails that range in sizes from 17 to 27mm in height. They are sexually dimorphic with females being larger than males , however, they are only 1 or 2cm larger.
|
 |
| Figure 3 |
|
|
|
Ecology |
Predator Avoidance | |
The predators of B.auratum are strongly associated with their habitat preference. In relation to mangrove and rocky outcrop habitats there are many species that commonly prey on B.auratum. These include: Toad fish (Tetractenos hamiltoni), Mottled Shore Crab (Paragrapsus laevis), Red handed Shore Crab (Sesarma erythrodactyla) as well as other species of gastropods including Alpheid shrimps (Underwood, A.J & Barrett, G. 1990).
Previous research suggests that predators are able to regulate the populations of B.auratum as many of the predators are keystone species to the habitats. B.auratum is able to avoid predation by being mobile species and the use of their hard shell. A study conducted by G.M Branch and M.L Branch, suggests that the regulation of mobile populations are dependent on competition more so than predation. However, as B.auratum is a herbivore the assumption can be made that the species will compete with other species for food more so than habitat space (Branch, G.M, 1980)
|
 |
| Figure 4 |
|
|
|
Preferential Habitat | |
The preferential habitat for the B.auratum is dependent on the area as they are commonly found in rocky outcrops as well as mangroves (Crowe, T.P Et.al., 1998). There is significant variation between these two habitats as they are largely influenced by human impact. Mangrove habitats are highly associated with the abundance of resources and the water level (Underwood, A.J Et.al., 1990). Individuals found on rocky outcrops are associated with the microhabitats that are accustomed to the high population of oyster colonies (Crowe, T.P, 1999). Figure 5 & 6, illustrates the two habitats that B.auratum are commonly found through-out South East Queensland.
The dispersal of B.auratum varies between the two habitats solely due to the influence of the other micro habitats. There is minimal research currently between the distributions of the two habitats. However, previous study suggests that there is a greater behaviour response in dispersal rates in comparison with their interaction with the environment (Crowe, T.P Et.al., 1999). This relationship between the individuals and the habitat is greatly influenced by environmental cues that encourage the dispersal between the two habitats. Individuals who have been taken from the mangrove habitats to the rocky outcrops illustrate a larger dispersal rate than originally born in the outcrop. In comparison if you remove an individual from the rocky outcrop and place it a mangrove habitat the dispersal rate will be lower than those born in the mangroves(Crowe, T.P Et.al., 1999). Along with the dispersal there is minimal research on the abundance and the distribution of the B.auratum in comparison with the health of the waterways. Therefore a study has been done in order to understand the relationship and the implications of an unhealthy waterway and the species, B.auratum.
|
 |
| Figure 5 |
|
 |
| Figure 6 |
|
|
|
Experiment | |
The distribution and abundance of Bembicium auratum in comparison with health of Shorncliffe and Boondall Wetlands, Brisbane in terms of the health of the waterways
The location of B.auratum highly depends on their age and the availability of resources. As previously stated there is minimal research on the abundance and whether there are higher distributions found closer or away from the shoreline. An experiment was conducted to analyse the distribution and the abundance found at two different locations, Shorncliffe (-27.328817, 153.088221) and Boondall Wetlands (-27.340342, 153.077506). The locations that were chosen for this experiment were selected due to the health of the waterway system. Both the locations are found in the area of the Cabbage Tree Creek. However, Shorncliffe is closely related to the Cabbage Tree Creek where-else Boondall Wetlands is associated with the Pine Catchment (Queensland Government, 2001). According to the Queensland Government, Healthy Waterways website, Boondall Wetlands is found in the Pine Estuary as it has been graded a B- as the waterway has an improved due to the decline algae and nutrients as well as a decline in the increased oxygen (Report Card, 2014a). Where-else Shorncliffe has been graded a D+ due to the decrease in turbidity and a slight incline in the amount of oxygen being dissolved (Report Card, 2014b). This area is highly urbanised and large amount of vegetation has been cleared from the water ways. This study hypothesizes there will be a larger population and therefore a greater distribution found in the healthier waterways. Suggesting there will be greater abundance in the Boondall Wetlands in comparison to the Shorncliffe area.
Method & Materials
This study will be completed during low tides as this allows easy access to the surveying the population of B.auratum. The experiment included running three transect lines from the cliff face to the shoreline. On each of these transects there will be four quadrats marked out at two meters on the tape. These quadrats will be placed one meter from the transect tape and will be used as the area for calculating each sample of abundance. The quadrats will be 1m by 1m in area. Over the three transects there will be a total of 36 samples across the three transect lines. The second and third transects will be placed in accordance with the Random Number table, which will be used to calculate how many steps away from the first transect it needs to be. Only 1 to 20 will be used on the Random number table. Along with the three transects there site will be broken up into three sections including: shoreline, middle and high tidal mark. These three sections will explain where there is a higher congregation of individuals. Across the two locations there will be a total of 72 samples.
The Statistical analysis that will be conducted for this study will be associated with a comparison of means in the three areas and will be graphed accordingly. The use of Two way ANOVA table will also be computed to recognise the significant value.
Results
The results illustrated that there is a significant interaction between the area and location in comparison with the population. In terms of the abundance, B.auratum was sampled to have a higher abundance in the rocky outcrop habitat (Shorncliffe) in comparison to the mangroves (Boondall). In terms of the location, the middle area was found to have the highest average number of B.auratum in the rocky outcrop with a value of 19.083 in comparison to the mangrove habitat with 4.75 (Figure 6). The second highest abundant area was the shoreline with a total of 5.083. The total sample size of the two locations in comparison was Rocky outcrops 328 individuals with Mangroves 123 individuals. In terms of the standard errors the highest was 0.694 on the middle area of the rocky outcrops. This suggests that the results found in this study had minor errors.
An analysis was supported by a ANOVA statistical analysis which explained that both the location and the area showed significantly influence in the B.auratum abundance separately. As well as the combination of both the location and the area acting on the population abundance (F2,66=13.94, P-value= 0.0221).
The results show that there is a significant interaction between the habitat and the abundance with the average and mean value higher in Rocky outcrops than Mangroves. The figure 6 suggests that more individuals would be found in the middle of the area even in comparison of the two locations; however more individuals are found in Shorncliffe. This could suggest that due to the decline in algae growth in the Pine estuary (B- grading) that fewer individuals would be found in lower algae growth areas find this location desirable. As algae are one of the main food sources of this species this could be a major cause into the motivation for the population to thrive in the area. In terms of the area of abundance in comparison with the location, the middle was found to have a higher abundance than the shoreline or higher up on the bank.
Previous research has suggested that more individuals would be more abundant in areas that are closer to the shoreline for juveniles while adults are more likely to be found higher in the shoreline (Crowe, T.P Et.al., 1998). However, the abundance of individual found higher in the bank past the tidal zone would be lower than those found in the inter-tidal. The study that was conducted for this research page, elaborates this theory in comparison with of the health of the water ways. Future studies could elaborate on the idea of using predation to understand whether there is any significant interaction between the choices of habitat. Another idea would be to investigate whether seasons have an effect on the population size of the two habitats.
|
 |
| Figure 7 |
|
|
|
|
Life History and Behaviour |
Reproduction | |
B.auratum is dioecious, meaning there is two sexes. As many species in the animal kingdom the reproductive systems of the two sexes are vastly different with both being highly complex. The male reproductive system is a Caenogastropod plan, which involves testis of tubules found in the digestive gland (Anderson, D. T., 1962). The sperm is stored in a seminal vesicle which is located adjacent to the columella, this is the section called the Visceral vas defens (Fretter.V, Et.al., 1962). This section is part of the large prostate gland. The sperm is passed over the head to the anterior vans defens to the penis. The penis is located behind the cephalic tentacles. Specifically to this species the anterior vans defens is closed, which means that the assumption could be made that they are plesiomorphic (“ancestral trait”). The penis shape is regarded wrinkled around the basal region and is slender as you move down to the base. (Reid, D.G. 1989). The size of the euspermatozoa is filiform and cannot be seen under the naked eye, as they are only visible by an electronic microscope. The invagination of this euspermatozoa is found to be shallow in this species in comparison to other species found in the Family Littorinidea.
In comparison the female reproductive system is broken up into two major regions: proximal oviduct and the renal section. The transfer of the egg from dorsal groove to the lumen occurs in an anterior direction (Borkowski, T.V. 1971). During copulation, the sperm will move in a posterior direction and therefore fertilisation will occur due to cross fertilisation. If the sperm is not fertilised immediately it will be transferred to the posterior seminal receptacle (Reid, D.G. 1989). After fertilisation the production of a gelatinous mass will occur. This mass will store the embryos for the incubated time.
The reproduction of this organism is through egg masses and adults spawn in the inter-tidal zones allowing the larvae to have a greater dispersal rate in the pelagic phase. The egg masses are released in the shoreline and inter-tidal zone in comparison to the adults where they are found higher in the shore (Branch, G.M, 1980). The production of a jelly mass allows the incubation of the eggs and will incubate for a periods of 10 days. During this time the larvae will develop and hatch as pelagic Planktotrophic Veligers. This means that more individuals are able to gather a greater dispersal than those found in the benthic environment due to biotic influences (Anderson, D. T., 1962).
|
|
|
Development | |
B.auratum larval development is planktotrophic larvae, which is defined as no assistance from a yolk sac (Lectitrophic). This development is significant to this species as other species found in the family are direct developers (Johnson, M.S Et.al., 2006). A defining characteristic of the Phylum Mollusca, the Class Gastropoda has a trochophore larvae stage. The larvae are characterised by the prototroch, which is defined as girdle of cilia located top of the larvae. As previously stated, Gastropods are planktotrophic; therefore the development of the cilia on the trochophore larvae is used for locomotion in the water column. Along with the protroch is the metatroch, telotroch and the apical tuft (Ruppert, E.E., Et.al. 2004).
It is unclear when exactly the torsion and coiling for the individual occurs, however there has been extensive study on the marine inter tidal snails that undergo this change in the adult life stage. (Noshita, K., Et.al., 2012) Torsion is through the effect of biological cues and occurs by the development of the shell from the mantle. In the visceral hump twists moving the visceral mass through a 180º twists which brings the mantle cavity and anus above the head (Ghiselin, M.T. 1966). In coiling, the shell that has developed from the torsion will begin to coil above the head creating whorls. These coils form around the columella (Raup, D.M. 1961).
|
 |
| Figure 8 |
|
|
|
|
Anatomy and Physiology |
External Anatomy | |
Shell
Similar characteristics that are shared throughout all gastropods are the structure of the shell (Refer to Figure 9). The shell begins with the apex, which is consistently known to be the oldest whorl. These whorls coil around the around the Columella (“central axis”) and finish at the Aperture (“opening of the shell”). The Aperture is the opening where the gastropods head and foot protrudes out. The Aperture is broken up into two lips: outer and inner lip. The inner lip is part of the last whorl and is semicircular. The outer lip is large and thin which can rapidly thicken with the age of the gastropod (Bianchi, A.M Et.al., 2012). The Siphonal canal (“extension of the aperture”) found at the tip of the inner and outer lip is associated with the ability to use chemical sensory in the environment (Vermeij, G.J, 2007). The shell is pyramid shaped or can be a depressed depending on the allometric growth thus suggesting the significance of growth between juveniles and adult body forms.
Head and Foot
The head-foot of littorinids is fused together with therefore a lack in neck lobes. Along with the lack of neck lobes there are cephalic tentacles attached to short snout of the head (Reid, D.G. 1989). There is no cilium present on the cephalic tentacles they are cylindrical and long. In the genus Bembicium, the head is in colour (Powell, A.W.B. 1979).
In terms of morphology the foot the development of the foot is considered as apomorphic. The foot of littorinids is broken up into three major regions: propodium, mesopodium and metapodium. The propodium is the anterior region where-else the metapodium is the posterior region. These two regions are separated by the mesopodium which is a deep transverse groove at the anterior edge (Reid, D.G. 1989). Along with the three regions there is a large anterior pedal gland which extends into the transverse groove (Shirbhate, R. Et.al., 1987). Another gland is located beneath the centre of the foot (Mesopodium) which is called the Posterior pedal gland.
Operculum
The operculum in molluscs is a proteinaceaous and is secreted by the gland cells found on the posterior end part of the foot. Along with the spiral cleavage in the shell the operculum also illustrates spiral growth pattern (Hashimoto, N., Et.al., 2012). In Littorinidea the operculum is coiled twofold and thickens by increasing the number of spirals in the shell. The inner side of the shell is thickened and has muscular tissue attached (Reid, D.G. 1989). The operculum is used to close up the aperture for protection (Ruppert, E.E., Et.al. 2004).
Mantle
The mantle of a gastropod is incredibly complex due to the arrangement of the gills, anus, and the development of a shell. The mantle sits above the visceral mass that is found in the mantle cavity (Reece, J.B., Et.al., 2014). As previously stated the mantle is used in larval development.
Cephalic tentacle
The cephalic tentacle located at the tip of the head of gastropods has been stated to be related to chemoreceptor’s sensory organs (Künz, E. Et.al., 2001,). In the Family Littorinidea, they are long and thin sitting just above the eyes. These tentacles do not have any obvious cilia present (Reid, D.G. 1989).
Mouth & Radula
The mouth of gastropods is complex structure due to the defining feeding structures. In simplest term, the mouth is a small opening located under the Cephalic tentacles. It is facing down-wards and pulls in food by using its radula as a ‘rake’ to pull algae and plant matter into the mouth.
The radula in Littorinids is long and coils around the mid-oesophagus. The length of the radula can be compared to the dimension of the shell with the radula being the greatest dimension (Reid, D.G. 1989). There is currently no research in the size of the radula in B.auratum, however there is research into the morphology of the radula in the Family Littorinidea. In terms of the size of the radula teeth, studies suggest a difference due to intra-specific variation from sexual dimorphism. This suggests that the structure of the radula teeth could be due to adaptation success. Similarity can be seen in the feeding, as sizes of the teeth are dependent on whether the Gastropod is a herbivore (Figure 10), carnivore or omnivore (Meirelles. C.A.O, Et.al., 2003). The assumption can be made that B.auratum, has small teeth which scrap the algae of mangrove pneumatophores and rocky outcrops.
As previously stated, the radula is a complex structure with a strategic framework. The radula is made up three main muscles for the retraction and the extension of the radula outside the mouth. These include: Odontophore extension muscle (OP), radula extension muscle and the radula retractor muscle. These three muscles act together in when feeding. These muscles can be seen on Figure 11, which shows the different sections of the mouth including the structure of the radula.
|
 |
| Figure 9 |
|
 |
| Figure 10 |
|
 |
| Figure 11 |
|
|
|
Internal Anatomy | |
The anatomy in B.auratum, in comparison with other species is fairly similar however there is little knowledge glands and musculature therefore a considerable amount of information will be based off the Family Littorinidae.
Salivary and the Hypobranchial Glands
There are multiple internal structures that are important for the development and the survival of B.auratum. As previously stated, there is little known an imperceptible amount of glands and muscles of this species. There is current knowledge on the salivary glands, hypobranchial glands and the Columellar musculature. The following structures will be explained throughout this section.
The internal structures of the salivary glands are for defence, feeding, reproduction, locomotion, lubrication and adhesion. These glands secrete a slime and mucus gel. B.auratum produces adhesive mucus and in order to secure itself to outcrop it covers the edge of the shell and the foot. The mucus is a combination of proteins and carbohydrates (Smith, A.M., 2010).
The hypobranchial gland is well developed in this species and along with the salivary gland produces mucus. The structure is also referred to as a mucus tract. This gland is located at the top of the mantle cavity. The colouration of this structure is deep red and is approximately 2mm in length (Reid, D.G. 1989).
Columellar Musculature
The Columellar muscle is attached to the columella and the operculum (located at the foot). It is flat and sheet like muscle that is used for retraction of the soft body into the shell (Figure 8). The muscle is three dimensional consisting of longitudinal muscle fibres as well as dorsal-ventral or transverse fibres and Oblique fibres (Thompson, J.T., Et.al., 1998).
|
 |
| Figure 12 |
|
|
|
Internal Systems | |
There is currently little knowledge on the different systems of this species, however, in comparison to other species and the major class of Gastropoda there is little difference between the species and the class. Therefore the information present in this section will be in relation to the whole Class of Gastropoda, in particular herbivores.
Digestive System
The digestive system of all gastropods is partially extracellular (meaning: occurs inside or outside the cell). All gastropods have a mouth, gut and anus (Refer to Figure 13 for a visual description). The position of these is highly dependent on the life stage (Reece, J.B., Et.al, 2014). Before torsion, the anus is facing to back of the individual. After torsion, the stomach is turned 180º and the anus is shifted above the mouth. All waste is expelled through the Operculum after torsion. Gastropods have a unique structure called the buccal cavity. This cavity contains the radula and the radula sac. In this cavity, there are also additional salivary glands and buccal glands (Hickman, C.P. 2014). Before the food reaches the stomach it must enter the oesophagus. This structure is broken up into three different sections: anterior, middle and posterior. During torsion the oesophagus will bend and twist, which is achieved by the middle as the anterior and posterior are fixed to the mouth and stomach. In the stomach of gastropods, extracellular digestion occurs with the breakdown of food by using enzymes. From the stomach to the anus, the intestine is positioned in visceral mass (Ruppert, E.E., Et.al, 2004).
Excretory system
The excretory system of marine gastropods can be ammonotelic or uricotelic, depending on where they live. In terms of B.auratum, the assumption can be made that due to living on intertidal zones they would swap between the two considering if it was high tide or low tide. Ammonotelic excretion is the ability to excrete nitrogen waste that is from amino acid catabolism. Uricotelic is similar to Ammonotelic although it is excreted in the form of urea (Allaby, M. 2014). In marine gastropods the nephridium is located in the visceral mass and surrounded by the hemocoel. At the end of this structure is the kidney which secretes the urine through the nephridopore. Large waste is secreted through the anus (Ruppert, E.E., Et.al, 2004).
Circulatory and Respiratory System
In terms of the circulatory system of marine gastropods it is structured by using the haemal system. This system includes the heart and pericardial cavity. These structures are positioned in the body depending on the life stage. In the adult form (after torsion) they are found in the anterior section of the visceral mass area (Voltzow, J. 1985). In terms of the heart, oxygenated blood is pumped into the aorta from the atrium. This is passed through the ventricle. This movement of blood is pushed into two areas the: visceral hemocoel and the cephalopedal hemocoel. The cephalopedal hemocoel supplies blood to the head and foot (Reece, J.B., Et.al, 2014).
The respiration of all molluscs is through a pair of gills. These gills are found in all gastropods and in B.auartum they are present in the mantle cavity above the anus. The gills are structured with a central axis and gill filaments (Ruppert, E.E., Et.al, 2004). The oxygen is transported to the bloodstream which is done by using the afferent brachial vessel. The current is a counter-current system with blood and oxygen crossing in opposite directions (Reece, J.B., Et.al, 2014).
Nervous and Sensory System
The symmetry for the nervous structure is bilaterally symmetrical and consists of cerebral, pedal, buccal, eosphageal and the multiple visceral ganglia (for a visual description please refers to figure 14). These components allow to the gastropod to be able to sense predators, tidal and other abiotic factors (Reece, J.B., Et.al, 2014). All gastropods do not have a brain and therefore the ganglia found on the visceral loops and pedal cord need to communicate by sending signals through nerve cells. These cells interact and are constantly being re-sent by the cerebral. The pedal cord in particular send signals to the cerebral when there is a pressure or movement and therefore the snail will retract back into its shell with the operculum closed for protection (Nordsieck, R. ,2015). In terms of the sensory system the gastropod is made up of four main structures: eyes, cephalic tentacles and the osphradia or osphradial. In particular to the eyes, are structured to only being able to register light (Tuchina, O. Et.al, 2010).
|
 |
| Figure 13 |
|
 |
| Figure 14 |
|
|
|
|
Evolution and Systematics | |
Mollusca, is one of the largest phylums found in the Animal Kingdom. This large phylum is broken up into six major classes: Gastropoda, Bivalvia, Scaphopoda, Cephlapoda, Alopachophora and Polyplacophora (Ruppert, E.E., Et.al, 2004). In terms of B.auratum, it is found in the Class Gastropoda and the clade Littorinimorpha. It is then broken into the Super family Littorinoidea which is extremely large in comparison with other superfamilies. This then follows to the genera Littoroinia (or Littorinids) which is grouped by the sperm cells being present in the penal glands and the glandular discs. The two genuses form a monophyletic group Bembicium and Risellopsis by the presence of salivary glands and the position of the seminal receptacle with the pallial oviduct (Reid, David G., 1988). The differentiation between the sister genus’s is proceeded mainly from allopatric divergence. Allopatric divergence is the difference in genes by an absence causing an interruption in the gene flow (Reid, D.G., Et.al., 2012).
There are minimal fossil records for the genera Littoroinia; however several species have had their estimated evolutionary age based off the genera Littoraria. This genera has been dated back to the Cretaceous period suggesting this genera could be a link to the ancestral intertidal snails (Williams, S.T., Reid, Et.al., 2003). Fossils records also suggest that due to lack of paraspermatozoa in Bembicium, they cannot be grouped with any other genus (Healy, J.M, 1996).
|
 |
| Figure 15 |
|
|
|
Biogeographic Distribution | |
Bembicium auratum are endemic to Australia and have a spatial distribution ranging from South Western Australia continuing to South Australia and Tasmania finally ending Northern Queensland. This distribution ranges approximately 7000km in area (Johnson, M.S ,Et.al., 2006).
|
 |
| Figure 16 |
|
|
|
Conservation and Threats | |
Due to the increase in global warming, more marine invertebrates are being affected by habitat loss, lack of resources, increase predation and introduced species and human impact (Powell, A.W.B. 1979). In particular with B.auratum, it is being greatly influenced by the increase in acidification in the oceans. Acidification has been a massive issue with dispersal rates for these gastropods and there have been several studies to analyse the rate of dispersal and their survival rates. These studies illustrated that more individuals would migrate out of the acidic waters when the pH was 6.2 to 7. The individuals also showed signs of retreating back into their shell when the pH was lower than 5 (Amaral, V., Et.al., 2014). The behaviour of the individuals also changed rapidly with more individuals climbing vertically up onto mangrove pneumatophores and rocky outcrops. This suggests that with the increase in acidic waters, the abundance of B.auratum in the current locations could change dramatically depending on the health of the waterways.
B.auratum is a viable species to investigate the water temperature in relation to zinc, copper and cadmium found in the body tissue. Several studies have illustrated that with the increase in pollutants more species will have a larger volume of these minerals in their body. This uptake has been the result from the increase in sea surface temperature and salinity. A large volume of these concentrations will have a greater impact on their survival due to the overdose in their body systems. The concentrations can have a dramatic influence on their reproductive and respiratory system. The influence on these systems has caused major issued with the development of embryos and egg masses (Taylor, A. Et.al., 2006).
Another conservation threat would be the habitat loss, in relation the increase in urbanisation. With the high demand for more human settlement in Australia there has been a major increase in building homes on the coastline. Not only are these houses being built on ocean fronts there are many significant implications for this settlement including: increase runoff, ripping out natural landscapes and the more human activities on the coastlines (Cheung, W.W.L., Et.al., 2009). Along with the acidification, the increase in runoff has cause massive effect on the habitats by increasing pollutants, sediment and nutrients. The abiotic factors have a major effect on the habitat and can be the cause for the decline and health of a species (Lee, S.Y., Et.al., 2006).
|
|
|
References | |
Allaby, M. 2014, A dictionary of zoology, Oxford University Press, New York.
Atlas of Living Australia, 2015, Bembicium auratum : Gold-mouthed Conniwink [ONLINE] Available at: http://bie.ala.org.au/species/Bembicium+auratum#. [Accessed 30 May 2015].
Amaral, V., Cabral, H.N & Bishop,M.J, 2014, “Prior exposure influences the behavioural avoidance by an intertidal gastropod, Bembicium auratum of acidified waters,” Estuarine, Coastal and Shelf Science, vol.136, pp.82
Anderson, D. T., 1962. The reproduction and early life histories of the gastropods Bembicium auratum (Quoy and Gaimard) (Fam. Littorinidae), Cellana tramoserica (Sower). (Fam. Patellidae) and Melanerita melanotragus (Smith) (Faro. Neritidae). Proc. Linn. Soc., New South Wales, 87, Pt. 1 (398): 62-68.
Bianchi, A.M & Fields, J. N, 2012, Gastropods: diversity, habitat and genetics, Nova Science, New York
Branch, G.M, 1980, “Competition in Bembicium auratum (Gastropoda), and its Effect on Microalgal Standing Stock in Mangrove Muds,” Oecolgia, vol.46, no.1, pp.106-114.
Bray, D. J. 2011, Common Toadfish, Tetractenos hamiltoni, Fishes of Australia, accessed 01 Jun 2015, http://www.fishesofaustralia.net.au/Home/species/879
Brusca, 2002, Torsion. [ONLINE] Available at:http://www.uas.alaska.edu/arts_sciences/naturalsciences/biology/tamone/catalog/mollusca/nucella_lima/Nucella_TORSION.html. [Accessed 31 May 2015].
Borkowski, T.V. 1971, "Reproduction and Reproductive Periodicities of South Floridian Littorinidae (Gastropoda: Prosobranchia)", Bulletin of Marine Science, vol. 21, no. 4, pp. 826-84
Cheung, W.W.L., Lam, V.W.Y., Sarmiento, J.L., Kearney, K., Watson, R. & Pauly, D. 2009, "Projecting global marine biodiversity impacts under climate change scenarios", Fish and Fisheries, vol. 10, no. 3, pp. 235.
Crowe, T.P & Underwood, A.J, 1998, “Testing behavioural preference for suitable microhabitats,” Journal of experimental marine biology and ecology, vol.225, no.1, pp.1-11
Crowe, T.P & Underwood,A.J, 1999, “Differences in dispersal of an intertidal gastropod in two habitats: the need for an design of repeated experimental transplantation,” Journal of experimental marine biology and ecology, vol.237, no.1, pp.31-60
Crowe, T.P, 1999, “Limits to generality: seasonal and temporal variation in dispersal of an intertidal gastropod”, Journal of experimental marine biology and ecology, vol. 232, no.2, pp. 177-196
Davey, K. (2005). Red-fingered Marsh Crab. [online] Australian Shore Crabs. Available at: http://keith-davey.com/shore-crabs/web-pages/redfingered-marshcrab.htm [Accessed 1 Jun. 2015].
Fretter,V & Graham,A., 1962, “British prosobranch molluscs, their functional anatomy and ecology”, London Ray Society.
Gestoso, I., Arenas, F. & Olabarria, C. 2015, "Feeding behaviour of an intertidal snail: Does past environmental stress affect predator choices and prey vulnerability?", Journal of Sea Research, vol. 97, pp. 66-74.
Ghiselin, M.T. 1966, "The Adaptive Significance of Gastropod Torsion", Evolution, vol. 20, no. 3, pp. 337-348.
Hashimoto, N., Kurita, Y. & Wada, H. 2012, "Developmental role of dpp in the gastropod shell plate and co-option of the dpp signaling pathway in the evolution of the operculum", Developmental biology, vol. 366, no. 2, pp. 367-373.
Healy, J.M, 1996, “Euspermatozoan ultrastructure in Bembicium auratum (Gastropoda): comparison with other Caenogastropods especially other Littorinidae”, Journal of Molluscan Studies, vol.62, no.1, pp.57-63
Hickman, C.P. 2014 “Integrated principles of zoology”, McGraw-Hill Education, Dubuque, Iowa.
Johnson, M.S & Black, R, 2006, “Effects of mode of reproduction on genetic divergence over large spatial temporal scales in intertidal snails of the genus Bembicium Philippi (Gastropoda: Littorinidae): Divergence in direct developers”, Biological Journal of the Linnean Society, vol.89, no.4, pp.689-704
Künz, E. & Haszprunar, G. 2001, "Comparative Ultrastructure of Gastropod Cephalic Tentacles: Patellogastropoda, Neritaemorphi and Vetigastropoda", Zoologischer Anzeiger - A Journal of Comparative Zoology, vol. 240, no. 2, pp. 137-165
Lee, S.Y., Dunn, R.J.K., Young, R.A., Connolly, R.M., Dale, P.E.R., Dehayr, R., Lemckert, C.J., McKinnon, S., Powell, B., Teasdale, P.R. & Welsh, D.T. 2006, "Impact of urbanization on coastal wetland structure and function", Austral Ecology, vol. 31, no. 2, pp. 149-163.
Meirelles.C.A.O, Matthews-Cascon. H, 2003, “Relations between Shell size and radula size in marine prosbranchs (Mollusca: Gastropoda)”, An International journal of marine science, Vol. 19, no. 2, pp.45-53
Msnucleus.org, 2015,” Comparing Herbivores and Carnivores” [online]. Available at: http://www.msnucleus.org/membership/html/k-6/lc/ntenvn/3/lcne3_5a.html [Accessed 4 May 2015]
Nordsieck, R. ,2015. Snails and Slugs (Gastropoda). [online] The living world of molluscs. Available at: http://www.molluscs.at/gastropoda/index.html?/gastropoda/morphology/radula/radula_function.html [Accessed 29 May 2015].
Noshita, K., Asami, T. & Ubukata, T. 2012, "Functional constraints on coiling geometry and aperture inclination in gastropods", Paleobiology, vol. 38, no. 2, pp. 322-334
Petraitis, P.S. 1982, "Occurrence of random and directional movements in the periwinkle, Littorina littorea (L.)", Journal of experimental marine biology and ecology, vol. 59, no. 2, pp. 207-217
Powell, A.W.B. 1979, New Zealand mollusca: marine, land, and freshwater shells, Collins, Auckland.
Quoy & Gaimard, 1834, “Bembicium auratum”. [ONLINE] Available at: http://seashellsofnsw.org.au/Littorinidae/Pages/Bembicium_auratum.htm [ Accessed 05 May 2015]
Queensland Government, 2001, South East Queensland Regional Water Quality Management Strategy 2001, Discover the waterways of South-east Queensland: waterways health and catchment management of South East Queensland, Australia.
Raup, D.M. 1961, "The Geometry of Coiling in Gastropods", Proceedings of the National Academy of Sciences of the United States of America, vol. 47, no. 4, pp. 602-609.
Reece, J.B., Meyers, N., Urry, L.A., Cain, M.L., Wasserman, S.A., Minorsky, P.V., Jackson, R.B., Cooke, B.J. & Campbell, N.A. 2014, Campbell biology, Pearson, Frenchs Forest, NSW.
Reid, D.G., Dyal, P. & Williams, S.T. 2012, "A global molecular phylogeny of 147 periwinkle species (Gastropoda, Littorininae)", Zoologica Scripta, vol. 41, no. 2, pp. 125-136.
Reid, David G., 1988. “The genera Bembicium and Risellopsis (Gastropoda: Littorinidae) in Australia and New Zealand”. Records of the Australian Museum 40(2): 91–150. [26 May 1988].
Reid, D.G. 1989, "The Comparative Morphology, Phylogeny and Evolution of the Gastropod Family Littorinidae", Philosophical Transactions of the Royal Society of London.Series B, Biological Sciences, vol. 324, no. 1220, pp. 1-110.
Riek, D. 2013a. CRUSTACEA - Paragrapsus laevis. [online] Roboastra.com. Available at: http://www.roboastra.com/Crustacea6/brde175.html [Accessed 1 Jun. 2015]., in Fishes of Australia, accessed 01 Jun 2015, http://www.fishesofaustralia.net.au/Home/species/879
Riek,D. 2013b, Prosobranchia- Bembicium auratum,[ONLINE] Available at: http://www.roboastra.com/Mollusc2/brpr164.html [Accessed 05 May 2015]
Report Card, 2014a, Pine Estuary [ONLINE], Avaliable at: http://healthywaterways.org/reportcard#/zone/1278/2014/estuarine [Accessed 05 May 2015]
Report Card, 2014b, Cabbage Tree Estuary, [ONLINE], Avaliable at:
http://healthywaterways.org/reportcard#/zone/1308/2014/estuarine [Accessed 05 May 2015]
Roach, A.C & Wilson, S.P, 2009, “Ecological impacts of tributyltin on estuarine communities in the Hastings River, NSW Australia,” Marine pollution bulletin, vol. 58, no. 12, pp. 1780-1786
Ruppert, E.E., Fox, R.S. & Barnes, R.D. 2004, Invertebrate zoology: a functional evolutionary approach, Thomson-Brooks/Cole, Belmont, Calif.
Shirbhate, R. & Cook, A. 1987, "Pedal and opercular secretory glands of Pomatias, Bithynia and Littorina", Journal of Molluscan Studies, vol. 53, no. 1, pp. 79-96.
Smith, A.M. 2010, "Gastropod Secretory Glands and Adhesive Gels" in Springer Vienna, Vienna, pp. 41-51
Taylor, A. & Maher,W. 2006, “The use of two marine Gastropods, Austrocochlea constricta and Bembicium auratum, as biomonitors of Zinc, Cadmium, and Copper Exposure: Effects of Tissue Distribution, Gender, Reproductive State and Temporal Variation,” Journal of Coastal Research [H.W.Wilson-AST], vol.22, no.2, pp.298
Thompson, J.T., Lowe, A.D. & Kier, W.M. 1998, "The Columellar Muscle of Prosobranch Gastropods: Morphological Zonation and Its Functional Implications", Invertebrate Biology, vol. 117, no. 1, pp. 45-56.
Tuchina, O. & Meyer-Rochow, V.B. 2010, "Regeneration of the visual system in gastropods (Mollusca)", Invertebrate Biology, vol. 129, no. 1, pp. 27-38.
Underwood, A.J & Barrett, G. 1990, “Experiments on the influence of oysters on the distribution, abundance and sizes of the gastropod Bembicium auratum in a mangrove swamp in New South Whales, Australia”, Journal of experimental marine biology and ecology, vol.137, no.1, pp.25-45
Uyeno, T. (2007). Ted Uyeno's Research Page. [online] Gastropodiatry: The foot of the snail. Available at: http://www2.nau.edu/~tau6/research%20gast.html [Accessed 1 Jun. 2015].
Vermeij, G.J, 2007, “The ecology of invasion: acquisition and loss of the siphonal canal in gastropods”, Paleobiology, vol.33, no.3, pp. 469-493
Voltzow, J. 1985, "Morphology of the pedal circulatory system of the marine gastropod Busycon contrarium and its role in locomotion (Gastropoda, Buccinacea)", Zoomorphology, vol. 105, no. 6, pp. 395-400
Ward, P. (2005). Mollusca. [online] Darwin's Galapagos. Available at: http://www.darwinsgalapagos.com/animals/molluscs.htm [Accessed 1 Jun. 2015].
Williams, S.T., Reid, D.G. & Littlewood, D.T.J. 2003, "A molecular phylogeny of the Littorininae (Gastropoda: Littorinidae): unequal evolutionary rates, morphological parallelism, and biogeography of the Southern Ocean", Molecular phylogenetics and evolution, vol. 28, no. 1, pp. 60-86.
|
|
|
|
|