5.2 Ecosystem functioning and services
What can biodiversity ‘do’ for us? Many of us do not really know the whole range of functions that natural ecosystems exert and without which our lives would become far more complex and difficult. These functions are ecosystem services and can be defined as all the activities and functions that an ecosystem performs naturally (“Ecosystem services are the suit of benefits that ecosystem provide to the humanity” (Cardinale et al. 2002)). For example, coastal waters supply us with food and other resources while at the same time absorbing many of our waste products like the urban discharges.
The services that the marine ecosystem provides for marine and coastal areas can be divided in three main categories:
1) provisioning services
2) regulating and maintenance services
3) cultural services
The provisioning services include the food supply, water storage and provision, and biotic materials and biofuels provision. The regulating and maintenance services are those that lessen the environmental change (e.g water purification, air quality regulation, coastal protection, climate regulation, ocean nourishment, life cycle maintenance and biological regulation).
The cultural services represent human value and enjoyment (i.e. symbolic and aesthetic values, recreation and tourism, and cognitive effects).
In the following table there are some more examples of ecosystem services from natural marine ecosystem (Costanza et al. 1997):
|Gas regulation||Oceans balacing CO2/O2 content in atmosphere, thus regolating atmospheric chemical composition|
|Provision of natural refugia||Habitats such as seagrasess and coral reefs as nursery grounds for fisheries|
|Food production||Coastal water as generators of fishery products|
|Provision of recreation||Offer opportunities for ecoturism|
|Provision of cultural assets||Offer resources for aesthetic, educational and scientific purposes|
Does biodiversity matter? There are reasons to believe that biodiversity conservation may be important in environmental protection. In marine communities the biodiversity has a central role in the so-called foundations species, like corals or sea grasess. Sea grasses exert a strong effect on shallow-water communities, among them the provision of shelter against predator, a nursery ground and food for many herbivores. Worldwide there are only about 50 species of sea grasses (e.g. the most know in the Mediterranean Sea is the Posidonia oceanica). In the 1930s a fungal disease wiped out the seagrass Zostera marina throughout the North Atlantic except for the Mediterranean Sea.
The biodiversity loss that it is experienced in human-dominated marine ecosystems has largely unknown consequences. Overall, ecosystem functioning developes with the increase of biodiversity. In contrast, marine biodiversity loss is progressively impairing the ocean’s capacity to provide food, maintain water quality, and recover from perturbations (Worm et al. 2006). One classical example of a collapsing ecosystem is illustrated by the fishing down the food web diagram, where the decline of fishes is represented (Pauly et al. 1998) (Fig.1_Ses5.2_Fishing down the food web_Pauly). When the fishing activity is intense, the relative abundance of large fish positioned as top predator in the food chain decreases. Consequently, small fishes start to dominate causing the decline of the mean trophic level of the catches. The progressive declines and changes degrade the ecosystem structure,leading to a situation where the ecosystem functioning are no longer supported.
In conclusion, maintaining the biodiversity of the marine environment is a necessity, but also a ‘duty’ for the present and future generations.
Cardinale BJ, Palmer MA, Collins SL (2002) Species diversity enhances ecosystem functioning through interspecific facilitation. Nature 415:426-429
Costanza R, d’Arge R, de Groot R, Farber S, Grasso M, Hannon B, Limburg K, Naeem S, O’Neill RV, Paruelo J, Raskin RG, Sutton P, van den Belt M (1997) The value of the world’s ecosystem services and natural capital. Nature 387:253
Pauly D, Christensen V, Dalsgaard J, Froese R, Torres F (1998) Fishing Down Marine Food Webs. Science 279:860-863
Worm B, Barbier EB, Beaumont N, Duffy JE, Folke C, Halpern BS, Jackson JBC, Lotze HK, Micheli F, Palumbi SR, Sala E, Selkoe KA, Stachowicz JJ, Watson R (2006) Impacts of biodiversity loss on ocean ecosystem services. Science 314:787-790
5.2.1 Give an example from your experience for provisioning service.
There are a lot of nature resources that are being used on a daily basis. Some are used as food providers, for education and scientific research etc. For instance, people hunt fish that are in the sea or in the rivers and when caught they serve as food. In this case, the sea “gave” us fish and it became one of the many sources of food today, but this can’t be taken for granted. By catching too much fish, we intervene in the food chain which causes a lot of problems for ecosystems. Maybe those problems are not visible immediately but in the long run they can cause some serious problems.
Some of the organisms that live in the water are used for medical purposes, such as leech. It has a special enzyme that lowers the process of blood coagulation. The leech is often put on your skin to suck your blood and in return the enzyme is injected in your blood. Marine life is also used for many experiments, some are eco-friendly, while some are very dangerous. Humans are trying to understand the life and behavior of mammals, so some of them are chipped. That way scientists can track them and examine them at any time. Besides all marine life, sea depths hold something much more precious to humankind than fish. It is oil. Oil is being pumped by enormous platforms built on the surface. This process is dangerous, even the slightest leak can cause kilometers upon kilometers of disaster.
Sadly, bringing animals to the aquarium is also a thing. Those caged animals are being used for educational purposes. I think that is not the best way to educate somebody, surely there is another way for those animals to be shown and presented to people. If aquariums are not enough, some of the animals, such as dolphins, are used for entertainment purposes. Those dolphins are put under a lot of hard training just to jump through loops and obey master’s requests. In my opinion, this is bad, because dolphins are being dragged away from their families and natural habitat.
5.2.2 Give an example from your experience for regulating and maintenance service.
Regulating and maintenance services in the marine ecosystems are, basically, the ways that seas naturally clean themselves. Regulating and maintenance services in marine ecosystems include: water purification, biological regulation, air quality regulation, climate regulation, coastal preservation and marine life cycle conservation.
There are various ways that nature uses to cope with that burden despite the harm dealt by both humans and other living creatures. I myself know, and have experienced, a few examples of Mediterranean Sea maintenance services. One of those examples is natural purification of the Croatian coast. The sea current coming from the south from the Ionian Sea passes through the Strait of Otranto and flows next to the eastern coast of the Adriatic Sea. While doing so it “collects” waste which then floats towards the Gulf of Venice, where it takes a turn and then passes next to the Italian coast and eventually exits the Adriatic Sea. That’s part of the reason why Croatia has cleaner sea than Italy. Seas and oceans also have a substantial effect on climate change and help in climate regulation. They are our main depositories of heat and carbon dioxide. That’s why there’s been a rapid increase of sea temperature which has contributed to the rise of the sea level. There’s also been increased pollution levels since the 18th century because seas and oceans possess about 40% of anthropogenic-sourced carbon dioxide from the atmosphere.
Another way in which seas and oceans affect the climate is through the hydrological cycle. Water evaporates into clouds which then move over the land and by raining (process of condensation) they reduce the temperature of landmasses. These are just some of the ways that help in regulating and maintenance services of the marine ecosystems.
In writing this short essay I used some of the information that I have found on the following page: https://www.sciencedirect.com/science/article/pii/S1470160X14004580.
5.2.3 Give an example from your experience for cultural service.
Cultural services are non-material beneﬁts people obtain from ecosystems through spiritual enrichment, cognitive development, reﬂection, recreation, and aesthetic experience, including knowledge systems, social relations, and aesthetic values. Cultural services include concerts, art exhibitions, community services, etc., things that you can attend, or help organise.
Cultural services are an important part of every community because they help people connect, spend time together, and help the community grow by working together on many projects. Those projects often are supported by volunteers and organisations as red cross and many more, but of course they have to include professionals to keep the level of organisation at the top level. I had great experience with cultural and community services, as I participated as a volunteer at the 2016 European Universities Games. That summer was overall great, but that experience will stay in my memory for the rest of my life, because you feel really good and motivated to help in such an event, and I met many interesting people, which I, three years later, still hear from and maintain contact. Other than sports events such as this, you can participate in many more. One radio station from Zagreb organised cleaning and fixing of playgrounds throughout the city, and luckily the playground on my block got on that list, so my friends and I gathered and came to help with a lot of other people form our ‘hood.
From my point of view, we should organise more events like those, or try to gather more information about cultural services events, because you help other people, the ecosystem, and it is really an exquisite feeling to see people enjoy the fruits of your labour.
5.2.4 Why biodiversity is important for the ecosystem services?
Biodiversity plays an important role in ecosystem functions that provide supporting, provisioning, regulating, and cultural services. These services are necessary for human well-being. Ecosystem functioning, and therefore ecosystem services, at any given moment in time are strongly influenced by the ecological characteristics of the most common species, not by the number of species.
Thus conserving or restoring the composition of biological communities, rather than simply maximizing species numbers, is critical to maintaining ecosystem services. Many changes in ecosystem services are brought about by the removal or introduction of organisms in ecosystems that disrupt ecosystem processes. Also, in aquatic habitats, the loss of species may also affect ecosystem processes. For example, coral reefs and the ecosystem services they provide are directly dependent on the maintenance of some key interactions between animals and algae, because coral reefs are habitats for many fish and other sea animals and also provide sea animals with food. The ocean plays a major role in climate regulation. Studies have shown that the seas absorb almost a third of the carbon dioxide emitted annually.
Mangrove trees, for instance, help retain soft or crumbly soil on the coast, and therefore help prevent coastal erosion. They are also natural barriers to water currents. Whale feces, on the other hand, contain high quantities of iron and the level of iron present in the ocean has a direct impact on the development of phytoplankton, a key component of carbon storage.
5.2.5 Posidoniaoceanica and its ecosystem services.
Posidonia oceanica is the most important endemic seagrass species of the Mediterranean Sea and it can form meadows or beds extending from the surface to 40–45 m of depth, depending on the clarity of water.
The Posidonia grows in large meadows that cover the sea floor and create an ecosystem with many functions. The meadows are a habitat and food for a big number of species. Posidonia oceanica has been called “the lungs of the Mediterranean” because it is one of the most important sources of oxygen provided to coastal waters. It is considered to be an indicator species of the overall quality of coastal waters since it is very sensitive to pollution and can only grow in clean unpolluted waters. Posidonia leaves also form compact and resistant structures along shores that provide a very effective protection against erosion. Dried Posidonia leaves were traditionally used in Mediterranean countries as packing material to transport fragile items of glassware and pottery, and also to ship fresh fish from the coast to the cities. The presence of Posidonia can be detected by the masses of decomposing leaves on beaches.
Posidonia oceanica is very sensitive to specific impacts such as bottom trawling, anchoring, coastal constructions, chemical wastes, fish farm effluents, desalination plants, geodynamic alterations, biological invasions and many others. The effect of these impacts, alone or combined, cause either a loss of vegetated areas, a reduction in seagrass abundance or a deterioration of plant health.
By Lovro Matković
Reference literature: www.medwet.org, www.posidoniagreenfestival.com, www.wikipedia.org,
5.2.6 Zoastera marina and its importance for the ecosystem.
Zostera marina is a species of seagrass commonly known as seawrack or common eelgrass. It is widely spread in seas in the northern part of the world which includes North America, Europe and some parts of Asia such as the area around Japan. It grows in colder seas, but it can also endure in warmer parts of the sea. It can live several months under the ice cover in colder seas.
This plant can reach over a meter long. It grows in muddy and sandy shores with enough sunlight, typically where the water is about 6 meters deep, and it is an important factor of the coastal ecosystem, providing a habitat for many different types of species. It also gives shelter so some fish can hide in it. As you can see, Zostera marina has great importance in the genetic diversity of sea living species. Some of the members of eelgrass communities are sea stars, crabs, snails, isopods and many more. It has an impact on humans too. For example, it keeps young salmon sheltered, which people later use as a source of food. Not only that, but it helps to build sediment which prevents beaches from erosion. Unfortunately, it is exposed to various threats. Water pollution, invasive species and human activities such as dredging (clearing the beds in waters) can harm this plant.
In conclusion, Zostera marina is a multi-benefit green plant which we must protect from extinction as well as other living beings. It has a huge impact and helps both humans and sea living creatures and it is catching ever more attention of humans in recent years because we are starting to understand how important Zostera marina is. It is enabling a whole sea ecosystem to grow and develop as well as people to build and maintain housing alongside the beaches and it also has an impact on the economy (from tourism, gastro-tourism, food production...).
It is a true example of how every individual is important. Because if there is one missing, the others will go missing too.
5.2.7 Do you think the marine biodiversity conservation is important? Why?
There is no doubt that marine biodiversity is important. The whole idea of the importance of marine biodiversity is quite simple; the more unique species there are, the more food ends up being provided for us, and things such as gas and climate regulations are a reality: the regulation of carbon dioxide and oxygen, as well as the maintenance of ozone, are important for us humans to survive. There is also, of course, the medicine and materials that we get from sea life, something that is the work of marine biodiversity. We also shouldn't ignore the cultural values of it, such as traditions that are associated with fishing communities.
I find marine biodiversity conservation important. Why? Let's start with the obvious, first; food provision. This is something that most people think about when being presented with the problem that comes with the lack of diversity. The biggest example of it is the diversity of coral reefs, due to the food and shelter they provide for other sea creatures. But, due to overfishing, sedimentation and human impact, coral reefs are in great need of conservation; the fewer coral reefs there are, the fewer sea creatures there are in general, and that means there is less food for us. This is extremely harmful to nations that depend on the coral reef ecosystems to survive.
So, we need to take care of marine ecosystems as a whole; we need the sea life to survive on land. However, is that it? Do we need to save the sea life and its biodiversity just because our own is in danger?
Is it alright to only notice problems of other species after our own is endangered? I think that marine biodiversity conservation is important, not just for of our own needs, but for the lives of sea creatures themselves, who are suffering due to human impact. In the end, it's only natural for humans to look after themselves. Still, I guess it doesn't really matter why we decided to protect marine biodiversity, but that we have finally started doing it.
5.2.8 Do you think that human activities can enhance the diversity loss? Give an example.
Biodiversity is the term that is given to describe the variety of life on earth and the natural patterns it forms. Without biodiversity, there would be no human existence. Humans affect biodiversity by their population numbers, use of land, and their lifestyles, causing species to go extinct.
Biodiversity provides humans with food, water, oxygen, energy, detoxification of waste, stabilization of earth’s climate, medicine, opportunities for recreation and tourism, and many more things. Currently there are 1.75 million species that have been identified; however, some speculate that there are at least 10 million living species on earth. Rates of extinction are currently up to 40,000 species per year. The two biggest problems that cause species extinction are habitat loss and fragmentation. Fragmentation is when a habitat is broken into smaller segments of land, as an example: putting a road in the middle of a habitat. As an example of species going extinct is the western black rhinoceros that went extinct in 2011. The main reason for this species going extinct was poaching because of its horn. The human population growth is considered to be the biggest problem in extinction of species. Human actions have also played a role in climate change, which is also causing great danger for biodiversity.
It is important for humans to realize the impact we have on biodiversity. Through proper education, and by demanding that governments make decisions to preserve biodiversity, the human population will be able to sustain life on earth longer. If humans become extinct, it will likely be a result of their own action or lack of action.