Marine Ecosystems

Limpets (Patella vulgate) live in algae rich environments on rocky shores. . It has been proposed that in more sheltered areas, limpet shells will grow to be flatter with a larger diameter, while in more exposed areas of coastline, they will grow a taller and narrower shell shape. To find out whether or not the shores of Aberdeen reflected this, samples were taken from two sites (Site A and Site B) along the Aberdeen coastline that varied in their exposure to wave action. The sites were chosen to provide two sample sites with a notable difference in their environment. In the more sheltered site A, limpets were not exposed to harsh waves, while at site B, there was significantly more wave action. Quadrats were used at both sites to provide an area of sampling for the limpets and they were placed around 5 meters from the waterline. The overall results from the study showed that there is a very strong relationship between diameter and height in Limpet shells and that there was an incredibly slight difference in the relationship between the two sites.

The lower shore, or low tide zone, is mostly submerged underwater. The most noticeable difference of this sub-region is the large diversity of different types of seaweeds. Organisms found in this zone are generally less adapted to periods of dryness. The creatures are generally the largest and most complex organisms on the shore as there are more sources of food as marine vegetation flourishes.

Although it supports a number of different organisms, Nudgee Beach lacks many of the fundamentals that make up a healthy and successful ecosystem. The first indicator of this is from the lack of birds present in the area. Although it has been noted for terrestrial bird species – such as kingfishers, pelicans, ibis, egrets, jabiru, stilts and heron – and wading bird species – such as golden plovers, curlews, tattlers and godwits – to have been spotted at Nudgee Beach and surrounding areas in the past; after a day’s worth of extensive observation and research, it was found that the birds observed were limited to magpie, ibis, great knot and eastern curlew species. To intensify this factor, at the time by which this lack of species was recorded, Nudgee Beach was expected to have started seeing tens of thousands of birds arrive for the migratory season [21]. This blatant lack of bird species diversity and quantity may have been due to the lack of small organisms within the ecosystem. The restricted number of small organisms at Nudgee Beach is detrimental to the entire ecosystem as these organisms make up the bottom levels of the food web and provide higher-level organisms with adequate amounts of food to consume. The smaller organisms expected to be observed – including; crustacean, shell, mollusc, lizard, frog, fish, worm, arachnid and insect species – was limited to the infrequent observation of crustacean, shell,

The sandy shores of beaches can be considered as a very harsh environment to live in (Ted Klenk, 1999). Survival in such a habitat requires an organism to withstand strong wave and current action, tidal rise and fall, unstable substrate, heavy predation and wide variations in salinity and temperature (The Otter Island Project). Any organism found in this type of harsh environment is specialized and highly adapted (The Otter Island Project).

Kelp forests are seen as the ultimate ecological engineer in coastal areas. They exist in marine environments spanning in southern California, Aleutian Islands, and the western north Atlantic. Light, latitude, and water temperature and nutrients all play a role in facilitating the growth of kelp forests all around the world, (Bolton). Kelp specifically dominates the shallow rocky coasts of the world‘s cold water marine habitats. Although they look as a free-growing plant, they are in fact primarily of brown algae. These structures provide food and shelter to a huge mix of biota, including crabs, sea urchins, mollusks, and other marine organisms (Steneck). The fronds, or large leaves of the kelp are the distinctive feature that can represent where a specific kelp may be found. The sizes of these organisms can range from the smallest found near California and Alaska at 5m to giant kelp up to 45m in length found on the west coasts of North and South America (Hamilton).

Coastal regions are strongly affected by water motion due to tides and wave energy Graham & Wilcox, 2000; Jonsson et al, 2006; Wolcott, 2007). Jonsson et al. (2006) found that Fucus vesiculosus located on the seaward side

Along the coasts of rocky beaches, an intricate ecological community inhabits the ‘rocky intertidal’ areas. The variety of rocks is home to an array of slimy, squishy, and colorful organisms. This intertidal community is comprised of nine species: three different algae, three stationary filter-feeders, and three mobile consumers. The three algae, Nori Seaweed, Black Pine, and Coral Weed, are the community’s producers and inhabit the bottom of the food chain. The next three species are stationary consumers. They are Mussel, Goose Neck Barnacle, and Acorn Barnacle. Because of their consumer status, they are more competitively dominant than algae. The last three components are the mobile consumers: Whelk, Chiton, and Starfish. They

The rocky shore is the intertidal zone, where the land meets the sea. It has a presence of large and small rocks, with the possibility of rock drop-offs or cliffs. There is a high presence of rock pools, containing an array of living and non-living organisms. The abiotic factors of the rocky shores

The variations of tidal levels have created different degrees of sun and air exposure that have resulted in three zones, generally, the supra-littoral zone, littoral zone and the sub-littoral zone (See Appendix A, Figure 3). Diverse animal and plant organisms excel at surviving and dealing with different degrees of abiotic and biotic factors and as a result the rocky shore ecosystem is comprised of a series of bands known as vertical, or in this instance, intertidal zonation (See Appendix A, Figure 1). Abiotic stresses such as light intensity and wave action typically set the upper boundaries where as biotic stresses set the lower boundaries and limit the distribution of many organisms to particular strata (See Appendix A, Figure 2). It is due to the species distribution among the different zones that the rocky shore ecosystems cannot be defined as a uniform habitat, rather a dynamic and complex one (Bamfield Marine Sciences Centre, 2013).

Rocky Shores are found where the sea meets the land which supports a diverse mix of plants and animals that have adapted to survive in the unique conditions of constant wave action as well as the fall of tides (Ehp.qld. 2016). Most of the ecosystems flora and fauna live in the intertidal zone, between high and low tide (Ehp.qld. 2016). They are exposed to two environments, being crushed by waves and swamped by the sea water, extreme temperatures and salinity, and left unprotected

The ocean is one of, if not, the largest biome on earth. There are more than one million species of marine life. Covering over 70 percent of the Earth’s surface, the ocean is our planet’s largest habitat, containing 99 percent of the living space on the planet. This area holds the life of nearly 50 percent of all species on Earth. Like lakes, oceans are subdivided into separate zones: intertidal, pelagic, abyssal, and benthic. All four zones have a great diversity of species. The intertidal zone is the region along the shoreline between average low tide and average high tide. In other words, this region goes through cycles of submergence and exposure to air. Animals in this zone must be able to survive the extended periods

It is shown that with the ocean, one of the biggest factors in order to promote the diversity within it is how fast the water flows, it is proven that with the increase in flow, along with it comes the number of invertebrate species that live under the rocks within that water. 3

Despite their proximity, the reef systems of Tela and Utila differed dramatically in D. antillarum population sizes, indicating that the population in Tela had recovered significantly post-mortality compared to Utila, where the population was still being supressed. D. antillarum in Utila also had a notably smaller average test size compared to Tela, likely due to a larger juvenile urchin population. Juveniles are less effective at grazing down algae populations and display significantly greater preference over the genera of algae they consume. In areas highly populated by juveniles, this would allow domination of certain fleshy brown genera such as Dictyota whilst species of the Caulerpa genus are grazed to a more regular coverage (Rivera and Turner, 2009). On Tela, individuals were more likely to reach maturity and grow larger; implying that on Utila there was a presence of ecological barriers limiting survival to maturity, which were not present on Tela. The rate of herbivory in each area highlights the importance of D. antillarum as a keystone species, as the Utilan reef showed clear signs of deterioration in health due to the dominance of fleshy-brown macroalgae (48.6%) and low coverage of scleractinian coral (19.4%) compared to Tela. The Tela reef showed a 68.3% dominance of scleractinian coral and significantly lower fleshy brow macro-algae coverage at 13.7%. This was particularly notable for a region with an average reported coral cover of <10% (Gardner et al., 2003).

The intertidal rocky shore of Caloundra Beach is inhabited by diverse range of biodiversity of animals and plants, many of which have developed high levels of adaptations throughout their existence. The very boundary of marine and terrestrial ecosystem, this environment is subjected to extremes of the physical environment such as temperature, desiccation, wave turbulence as well the ecological interactions that commonly occur in biotic communities (e.g. competition, predation). However Rocky intertidal shores are easily accessible by humans and provide an enjoyable opportunity for passive recreation and for science and environmental education as well.

The investigation of these tidal zones showed that most of the organisms are not evenly distributed. The tidal organisms are often hidden in cracks, shades and gullies to prevent them from being dislodged by the wave action or desiccation.