Difference between revisions of "Marine mammals' health as an indicator of ecosystem health - tools for monitoring"

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[[Image:Kakuschke_4.jpg|thumb|300px|right|'''Figure 4''': Cytokine index of IL-2 mRNA from the blood samples of two harbour porpoises living in captivity (Pp1, Pp2) and four accidentally caught animals (Pp3-Pp6)(Fonfara et al. 2007)]]
 
[[Image:Kakuschke_4.jpg|thumb|300px|right|'''Figure 4''': Cytokine index of IL-2 mRNA from the blood samples of two harbour porpoises living in captivity (Pp1, Pp2) and four accidentally caught animals (Pp3-Pp6)(Fonfara et al. 2007)]]
  
===Metal pollution – effects on immune system===  
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===Metal pollution – effects on the immune system===  
 
Pollution by metals may affect the immuno-competence of free-ranging populations of marine mammals in many areas of the industrialised world. An imbalance of the immune system caused by pollutants has been suggested to play a role in the incidence of infectious diseases in marine mammals (Jepson et al., 1999<ref name="J">Jepson, P. D., Bennett, P. M., Allchin, C. R., Law, R. J., Kuiken, T., Baker, J. R., Rogan, E. & Kirkwood, J. K. (1999). Investigating potential associations between chronic exposure to polychlorinated biphenyls and infectious disease mortality in harbour porpoises from England and Wales. Science of the Total Environment, 244, 339-348.</ref>; Siebert et al., 1999<ref name="S">Siebert, U., Joiris, C., Holsbeek, L., Benke, H., Failing, K., Frese, K. & Petzinger, E. (1999). Potential relation between mercury concentrations and necropsy findings in cetaceans from German waters of the North and Baltic Seas. Marine Pollution Bulletin, 38 (4), 285-295.</ref>; Bennett et al., 2001<ref name="B">Bennett, P. M., Jepson, P. D., Law, R. J., Jones, B. R., Kuiken, T., Baker, J. R., Rogan, E. & Kirkwood, J. K. (2001). Exposure to heavy metals and infectious disease mortality in harbour porpoises from England and Wales. Environmental Pollution, 112 (1), 33-40.</ref>). Metals affect the function of immuno-competent cells by a variety of mechanisms. Depending on the particular metal, its speciation, concentration and bioavailability, and a number of other factors, a continuous metal exposure will result in immuno-suppression or immuno-stimulating effects.
 
Pollution by metals may affect the immuno-competence of free-ranging populations of marine mammals in many areas of the industrialised world. An imbalance of the immune system caused by pollutants has been suggested to play a role in the incidence of infectious diseases in marine mammals (Jepson et al., 1999<ref name="J">Jepson, P. D., Bennett, P. M., Allchin, C. R., Law, R. J., Kuiken, T., Baker, J. R., Rogan, E. & Kirkwood, J. K. (1999). Investigating potential associations between chronic exposure to polychlorinated biphenyls and infectious disease mortality in harbour porpoises from England and Wales. Science of the Total Environment, 244, 339-348.</ref>; Siebert et al., 1999<ref name="S">Siebert, U., Joiris, C., Holsbeek, L., Benke, H., Failing, K., Frese, K. & Petzinger, E. (1999). Potential relation between mercury concentrations and necropsy findings in cetaceans from German waters of the North and Baltic Seas. Marine Pollution Bulletin, 38 (4), 285-295.</ref>; Bennett et al., 2001<ref name="B">Bennett, P. M., Jepson, P. D., Law, R. J., Jones, B. R., Kuiken, T., Baker, J. R., Rogan, E. & Kirkwood, J. K. (2001). Exposure to heavy metals and infectious disease mortality in harbour porpoises from England and Wales. Environmental Pollution, 112 (1), 33-40.</ref>). Metals affect the function of immuno-competent cells by a variety of mechanisms. Depending on the particular metal, its speciation, concentration and bioavailability, and a number of other factors, a continuous metal exposure will result in immuno-suppression or immuno-stimulating effects.
  

Revision as of 11:50, 25 February 2013



Introduction

Figure 2:Overview of immunological investigations using blood samples of marine mammals.
Marine mammals, are used as indicators of ecosystem change (Trilateral Monitoring and Assessment Program, TMAP, Fig. 1). They are top predators in the marine food web. Increasing industrial and commercial activity, e.g. fisheries and offshore drilling and wind parks, as well as the input of pollutants, affect the North Sea and Baltic Sea ecosystems, including native marine mammals such as Harbour Porpoises (Phocoena phocoena), Harbour Seals (Phoca vitulina) and Grey Seals (Halichoerus grypus).
Figure 1: The health of the Harbour Seal as top predator is an important biological parameter of the Trilateral Monitoring and Assessment Program (TMAP). This program was founded by The Netherlands, Denmark and Germany, for the protection and conservation of the Wadden Sea. It includes management, monitoring and research, as well as political matters.
This article presents some tools for early diagnosis of the health status of Harbour Seals. The selected biomarkers are non-destructive and are parameters for the immune system, which plays a central role in the control of disease processes. The dysregulation of the immune system may lead to immune suppression or enhancement (hypersensitivity). The indicators for the effects of pollutants are identified and chemically characterised.

Methodology

The following immune system parameters can be measured in blood samples of captive and wild living animals using biomolecular and biochemical methods(Fig. 2, Fig. 3): lymphocyte proliferation as important immune cell function, and the expression of cytokines released by immune cells, which participate in an immune reaction.

Figure 3: Directly after arrival in the Seal Station the lymphocytes of newborns were particularly susceptible to the toxic effect of metals. A lot of metals tested e.g. beryllium, lead and cadmium inhibit the lymphocyte proliferation (value <0.1). This effect decreased during the time of rehabilitation.

Measurement of lymphocyte proliferation

Lymphocytes are isolated from the blood sample and cultured with and without stimulation using a lymphocyte transformation test (LTT, Fig. 2). After incubation, transformation and proliferation are examined and a stimulation index is calculated.

Quantification of cytokine expression

Cytokine expression is measured by analysing the amount of mRNA with the real time reverse transcriptase polymerase chain reaction (RT-PCR, Fig. 2). Detecting the amount of the mRNA allows us to calculate ratios between cytokines and thus establish the main focus of the immune response. Investigations of the cytokine expression pattern (Interleukin-1, -2, -4, -6, -10, -12, TNF, TGFß) allow the status of the immune reaction to be differentiated, whether the emphasis is on the cellular or humoral (body liquid) immune response.

Figure 4: Cytokine index of IL-2 mRNA from the blood samples of two harbour porpoises living in captivity (Pp1, Pp2) and four accidentally caught animals (Pp3-Pp6)(Fonfara et al. 2007)

Metal pollution – effects on the immune system

Pollution by metals may affect the immuno-competence of free-ranging populations of marine mammals in many areas of the industrialised world. An imbalance of the immune system caused by pollutants has been suggested to play a role in the incidence of infectious diseases in marine mammals (Jepson et al., 1999[1]; Siebert et al., 1999[2]; Bennett et al., 2001[3]). Metals affect the function of immuno-competent cells by a variety of mechanisms. Depending on the particular metal, its speciation, concentration and bioavailability, and a number of other factors, a continuous metal exposure will result in immuno-suppression or immuno-stimulating effects.

- Metal induced hypersensitivity in seals

The chronic intake of metal pollutants makes marine mammals susceptible to developing hypersensitivity reactions. Metal-specific hypersensitivity reactions were found in different pinnipeds from the North Sea (Kakuschke, 2006[4]). The frequency of sensitising metals was in the order Mo > Ni >Ti > Cr, Al > Pb, Be, Sn. A relationship was found between the blood levels of metals to metalspecific hypersensitivity reactions (Kakuschke et al., 2005[5]). A relationship between lymphocyte proliferation and cytokine expression could be shown: in a study of a grey seal, a hypersensitivity reaction to Ni and Be has been correlated to alterations in the cytokine pattern (Kakuschke et al., 2006[6]).

- High susceptibility of the immune system of pups to the toxic effect of metals

Pups are exposed to metals due to the transplacental transfer mother/fetus, the transfer through the milk and later by contaminated prey. Kakuschke et al. (2007[7]) found that lymphocytes of seal pups are particularly susceptible to the toxic effects of metals in the newborn period and that this susceptibility decreases subsequently.
Figure 5: In cooperation with the FTZ Büsum seals were caught in the Danish and German Wadden Seas, specifically at the Islands Rømø and Helgoland and the sandbank Lorenzenplate. The seals were caught with a long net and for further investigations put in small individual nets. Several clinical parameters were collected and blood samples were taken. Additional blood samples were taken from pups during rehabilitation in the Seal Station Friedrichskoog.

Stress – effects on the immune system

The cytokine expression can be modulated by numerous factors, including stress. Fonfara et al. (2007[8]) compared cytokine mRNA expression from harbour porpoises exposed to different environments. Blood samples were taken from two healthy porpoises living in captivity at the Fjord and Belt Centre Kerteminde, Denmark, and from four wild porpoises accidentally caught in Danish waters. The results are suggestive of stress-induced modulation of the immune responses in the accidentally caught animals (Fig. 4, Fig. 5).

Challenges

Anthropogenic influences may lead to changes of the health status of animals. A set of reliable health parameters enables us to investigate routinely a high number of animals and to obtain information from indicators of the coastal ecosytem health, monitored in support of the Trilateral Monitoring and Assessment Program.

See also

Internal links

References

  1. Jepson, P. D., Bennett, P. M., Allchin, C. R., Law, R. J., Kuiken, T., Baker, J. R., Rogan, E. & Kirkwood, J. K. (1999). Investigating potential associations between chronic exposure to polychlorinated biphenyls and infectious disease mortality in harbour porpoises from England and Wales. Science of the Total Environment, 244, 339-348.
  2. Siebert, U., Joiris, C., Holsbeek, L., Benke, H., Failing, K., Frese, K. & Petzinger, E. (1999). Potential relation between mercury concentrations and necropsy findings in cetaceans from German waters of the North and Baltic Seas. Marine Pollution Bulletin, 38 (4), 285-295.
  3. Bennett, P. M., Jepson, P. D., Law, R. J., Jones, B. R., Kuiken, T., Baker, J. R., Rogan, E. & Kirkwood, J. K. (2001). Exposure to heavy metals and infectious disease mortality in harbour porpoises from England and Wales. Environmental Pollution, 112 (1), 33-40.
  4. Kakuschke, A. (2006). Einfluss von Metallen auf das Immunsystem von Meeressäugern. Dissertation, Universität Hamburg.
  5. Kakuschke, A., Valentine-Thon, E., Griesel, S., Fonfara, S., Siebert, U. & Prange, A. (2005). The immunological impact of metals in Harbor Seals (Phoca vitulina) of the North Sea. Environmental Science & Technology, 39 (19), 7568-7575.
  6. Kakuschke, A., Valentine-Thon, E., Fonfara, S., Griesel, S., Siebert, U. & Prange, A. (2006). Metal sensitivity of marine mammals: a case study of a gray seal. Marine Mammal Science, 22 (4), 985-997.
  7. Kakuschke, A., Valentine-Thon, E., Fonfara, S., Griesel, S., Siebert, U. & Prange, A. (2008). Metal-Induced Impairment of the Cellular Immunity of Newborn Harbor Seals (Phoca Vitulina). Archives of Environmental Contamination and Toxicology,55 (1), 129-136. doi: 10.1007/s00244-007-9092-3
  8. Fonfara S., Siebert, U. Prange, A. & Colijn, F. (2007). The impact of stress on cytokine and Haptoglobin mRNA expression in blood samples from harbour porpoises (Phoconea phocoena). Journal of the Marine Biological Association of the United Kingdom, 87, 305-311.



The main author of this article is Kakuschke, Antje
Please note that others may also have edited the contents of this article.

Citation: Kakuschke, Antje (2013): Marine mammals' health as an indicator of ecosystem health - tools for monitoring. Available from http://www.coastalwiki.org/wiki/Marine_mammals%27_health_as_an_indicator_of_ecosystem_health_-_tools_for_monitoring [accessed on 28-03-2024]


The main author of this article is Kramer, Katharina
Please note that others may also have edited the contents of this article.

Citation: Kramer, Katharina (2013): Marine mammals' health as an indicator of ecosystem health - tools for monitoring. Available from http://www.coastalwiki.org/wiki/Marine_mammals%27_health_as_an_indicator_of_ecosystem_health_-_tools_for_monitoring [accessed on 28-03-2024]


The main author of this article is Fonfara, Sonja
Please note that others may also have edited the contents of this article.

Citation: Fonfara, Sonja (2013): Marine mammals' health as an indicator of ecosystem health - tools for monitoring. Available from http://www.coastalwiki.org/wiki/Marine_mammals%27_health_as_an_indicator_of_ecosystem_health_-_tools_for_monitoring [accessed on 28-03-2024]