Helfield, J. M. , and R. J Naiman . 2001. Effects of Salmon-Derived Nitrogen on Riparian Forest Growth and Implications for Stream Productivity. Ecology 82: 2403-2409. What was the main point of the article that you chose? This study aims to explore how terrestrial ecosystems are linked to aquatic ecosystems, particularly through resources. This is examined by observing how MDN affects riparian growth. Briefly explain or describe the scientific method presented in the article. a. What was the hypothesis? Marine derived nitrogen (MDN) has an effect on riparian vegetation. b. What were the predictions? Areas with a high level of MDN such as salmon reproductive areas, will have more enhanced riparian growth than a non-reproductive …show more content…
The independent variable is the levels of MDN. b. What kind of study was it? Observational? Experimental? Modelling? This is an observational study as no treatments were placed on the study sites, instead samples were taken from sites of interest and analyzed. c. What statistics were used? Three major descriptive statistics calculations were done. Firstly, the basal area increment (BAI) was found for tree growth, the ratio of N15 to N14, 15N was calculated, and the %MDN of the samples was found. d. What assumptions were made? This study assumes that nitrogen is the limiting factor to riparian growth. Another is that MDN is the most significant contributor to nitrogen levels in the study site. What was the primary finding(s) of this article? Helfield and Naiman’s results showed that foliar N levels and 15N were significantly higher at spawning sites compared to the reference sites. They suggest that their hypothesis is supported and MDN provides nutrition to riparian vegetation. a. Was anything particularly noteworthy? Helfield and Naiman propose that there could be a positive feedback loop in which MDN helps riparian vegetation growth and in return the stream receives LWD (large woody
inorganic and organic nutrients The materials or compounds and elements found in all the spheres. Only in recent time have they began to understand the diversity roles of the biosphere. Each specie and species of a community contribute to the ecosystem. Ecosystems depend on chemical and physical conditions, along with the number communities and species of all the locations such as grasslands, forest and wetlands to name a few. The processes of the ecosystem and biodiversity is sensitive to the declines. Local biodiversity declines are more important than the declines globally. These changes in the biodiversity influence the process of the ecosystem. When the diversity that is local declines the production of plants may also decline and this brings variables into the ecosystem.( Naeem, Chapin III, Costanza, Ehrlich, Golley, Hooper, Lawton, ONeill, Mooney, Sala, Symstad, Tilman,1999)
These two studies investigated the role of coastal habitats and ecosystems in relation to their productivity at the primary and secondary levels, as well as how these ecosystems are capable of shaping the dynamics of neighboring systems. The study conducted by Heck focused exclusively on seagrass ecosystems and their interconnectedness with nearby and distant habitats. The researchers investigated biomass exchanges that occur through both passive and active means. Consumers accomplish active transport as they directly transport biomass into and out of seagrass meadows. Passive transport of seagrass biomass is associated with roots, rhizomes and seagrass detritus that’s is carried out of the system by currents and waves. Therefore, the review conducted by Heck primarily focused on the role of primary production within seagrass ecosystesms. The decline of seagrass habitats is predicted to not only have effects upon the organisms that directly dwell in and feed off of them, but will also have far reaching effects on adjacent and distant habitats that they contribute to in the form of energy and biomass transfers. In contrast, the study conducted by Wong and her team, looked at a number of different types of estuarine coastal habitats and evaluated them based on their secondary production, in relation to their ability to contribute and sustain ecosystems. Ultimately, the researchers determined the values of these habitats based on their secondary production, and hope that their findings will help to direct restoration efforts in the future to protect those habitats with higher value based on ecological metrics.
Mroz, G. D., Jurgensen, M. F., Harvey, A. E., and Larsen, M. J., 1980, Effects of fire on nitrogen in forest floor horizons: Soil Science Society of America Journal, v. 44, p. 395-400.
Mitsch, William J., and Gosselink, James G., 1993, Wetlands, Second Edition: New York, Van Nostrand Reinhold, 722 p.
Riparian areas are the “in between” places between on land and aquatic ecosystems. It allows the transportation between the aquatic and the land ecosystems and the distribution of nutrients, which helps balance the surrounding ecosystems. Riparian areas are vital in stopping erosion, which can be a major problem for farmers and the surrounding areas. With less erosion happening, farmers are able to use more land, and not have to worry about the crops right near the stream. Riparian areas also help filter out pollutants like pes...
.Smith, V. H., Tilman, G. D., & Nekola, J. C. (1999). Eutrophication: impacts of excess nutrient
“The Great Bear Rainforest is home to over 2,500 salmon runs.” (Temple, 2005) At the moment, the Pacific salmon is the evident species inhabiting the forest. Salmon are keystone species. This means that they play a vital part towards the ecosystem together as a “critical food source for many wildlife species and as an upstream vector in the distribution of marine-deprived nutrients through the forest.” (David Suzuki Foundation, 2005) When this forest gets cut down, the entire ecology of the nearby water bodies drastically changes in a negative m...
In addition, several studies indicate that potential soil nitrification effects differ among ecosystems, and that these differences do not seem to be associated directly with physical or chemical soil characteristics (Clark et al., 1960, Hattenschwiler and Vitousek, 2000; Lata et al., 2004; Laverman et al. 2000; Lovett et al. 2004; Montagnini et al. 1989; Northup et al. 1995; Robertson, 1982 a, Robertson, 1982 b and Schimel et al., 1998). In several other studies, it was shown th...
The aim of the following experiment is to determine the correlation between the level of nitrates in the water and the growth of duckweed. It is expected that the increased amount of nitrates in the water will cause the duckweed to grow. The duckweed is expected to absorb the nitrates as it grows and therefore lower the levels of nitrates in the water. This is a valid aim as the results could be used as a method of deterring and removing eutrophication in bodies of water where other methods may not be suitable. It is expected that the higher levels of nitrates will cause duckweed colonies in a body of water to grow in population at the same time lowering levels of nitrates in the water.
With reference to at least ONE ecosystem you have studied, explain the biophysical interactions which lead to diverse ecosystems and their functioning.
The aquatic ecosystems are home to some of the most diverse life forms on the planet. From plankton and plants to fish and even to large mammals, the aquatic ecosystem provides shelter to such a diverse range of life that few other ecosystems can ever compare to this large scope. In the aquatic ecosystem, there are many factors that allow for biotic life to flourish. Some of these factors include biodiversity, energy flow, and nutrient cycling. Not only do these factors allow for the prosperity of the aquatic ecosystem function, but also allow for the proper function of the other factors.
Many ecological effects can arise from stimulating primary production, but there are three particularly troubling ecological impacts: decreased biodiversity, changes in species composition and dominance, and toxicity effects.
Human-induced alteration of biogenic habitats at the landscape scale is increasing, and directly influencing local diversity and system functioning (Vitousek et al. 1997, Duarte 2002, Lozte et al. 2006 and Airoldi & Beck 2007). Alteration of natural landscapes can result in loss of entire habitats or transition of more complex to less complex habitats, for example shellfish reefs or seagrass beds to mud flats (Short and Wyllie-Echeverria 1996, Hughes et al. 2002, Ruesink et al. 2005, Thrush et al. 2006). Alterations in habitat can generate unsuitable habitat between isolated patches of contiguous habitat (MacArthur & Wilson 1967, Hanski 1994). These changes in turn, have a direct effect on the dynamics of a community (total abundance, diversity and species richness), especially the design and influence of functional roles of species occupying the system (Gray 1997, Tilman et al. 1994, Loureau et al. 2001). For example, much some of the temperate continental shelf are being homogenized from bottom trawling and dredging, resulting in loss of individuals and functional groups (Thrush and Dayton 2002, Gray et al. 2006). The synergistic effects of the loss of quantity and of quality habitat, and the timing and configuration of habitat alteration may result in threshold levels of habitat loss below which faunal diversity, abundance, and survival can be resilient.
Eutrophication is defined as excessive richness of nutrients in a lake or other body of water. It is frequently due to runoff from the land, which causes a dense growth of plant life and, a subsequent death of animal life from a concentration lack of oxygen resulting from the oxidation of organic matter (Chrislock et al., 2013). Eutrophic systems can be observed to have shallow waters, high concentrations of nutrients, high productivity, and high oxygen usage. This process of eutrophication occurs naturally and is caused primarily by the accumulation of nitrogen and phosphorus. Waters that go through the process of eutrophication have a tendancy to move towards hypoxia or even anoxia. Hypoxic waters have 2-3 ppm of dissoled oxygen and anoxic waters having no dissolved oxygen. Although waters can undergo eutrophication naturally, it can also be accelerated by anthropogenic means. This human caused acceleration is refered to as cultural