scholarly journals More than just fish food: ecosystem services provided by freshwater insects

2015 ◽  
Vol 40 ◽  
pp. 113-123 ◽  
Author(s):  
CRAIG R. MACADAM ◽  
JENNI A. STOCKAN
Author(s):  
Waykin Nopanitaya ◽  
Joe W. Grisham ◽  
Johnny L. Carson

An interesting feature of the goldfish liver is the morphology of the hepatic plate, which is always formed by a two-cell layer of hepatocytes. Hepatic plates of the goldfish liver contain an infrequently seen second type of cell, in the centers of plates between two hepatocytes. A TEH study by Yamamoto (1) demonstrated ultrastructural differences between hepatocytes and centrally located cells in hepatic plates; the latter were classified as ductule cells of the biliary system. None of the previous studies clearly showed a three-dimensional organization of the two cell types described. In the present investigation we utilize SEM to elucidate the arrangement of hepatocytes and bile ductular cells in intralobular plates of goldfish liver.Livers from young goldfish (Carassius auratus), about 6-10 cm, fed commercial fish food were used for this study. Hepatic samples were fixed in 4% buffered paraformaldehyde, cut into pieces, fractured, osmicated, CPD, mounted Au-Pd coated, and viewed by SEM at 17-20 kV. Our observations were confined to the ultrastructure of biliary passages within intralobular plates, ductule cells, and hepatocytes.


2019 ◽  
Vol 3 (1) ◽  
pp. 1-14
Author(s):  
Philip Brick ◽  
Kent Woodruff

This case explores the Methow Beaver Project (MBP), an ambitious experiment to restore beaver (Castor canadensis) to a high mountain watershed in Washington State, USA. The Pacific Northwest is already experiencing weather regimes consistent with longer term climate projections, which predict longer and drier summers and stronger and wetter winter storms. Ironically, this combination makes imperative more water storage in one of the most heavily dammed regions in the nation. Although the positive role that beaver can play in watershed enhancement has been well known for decades, no project has previously attempted to re-introduce beaver on a watershed scale with a rigorous monitoring protocol designed to document improved water storage and temperature conditions needed for human uses and aquatic species. While the MBP has demonstrated that beaver can be re-introduced on a watershed scale, it has been much more difficult to scientifically demonstrate positive changes in water retention and stream temperature, given hydrologic complexity, unprecedented fire and floods, and the fact that beaver are highly mobile. This case study can help environmental studies students and natural resource policy professionals think about the broader challenges of diffuse, ecosystem services approaches to climate adaptation. Beaver-produced watershed improvements will remain difficult to quantify and verify, and thus will likely remain less attractive to water planners than conventional storage dams. But as climate conditions put additional pressure on such infrastructure, it is worth considering how beaver might be employed to augment watershed storage capacity, even if this capacity is likely to remain at least in part inscrutable.


2016 ◽  
Vol 3 (3) ◽  
pp. 48-53 ◽  
Author(s):  
G. Chobotko ◽  
L. Raychuk ◽  
I. McDonald

The aim of the article was to defi ne the role of the radioactive environment contamination in the formation of ecosystem services strategy. Methods. Monographic, systemic and structural, factor analysis, abstract and logical research methods have been used. The data from the State Statistics Service of Ukraine, the Ministry of Agrarian Policy and Food of Ukraine, the Ministry of Ecology and Natural Resources of Ukraine, materials of scientifi c researches, international materials and reports and other literary sources on the issues investigated have been used as an information base. Results. Retrospective analysis of sources and state of radioactive eco- systems contamination was conducted and the priority steps in developing the concept of ecosystem services in conditions of radiation contamination were found. Conclusions. The current socio-ecological paradigm of the transition from environmental use to environmental management should be refl ected in the relevant envi- ronmental management mechanisms. Currently, when assessing the state of ecosystem services in Ukraine and worldwide one must take into account the changes in food demand of residents of radioactively contaminated areas, the exploitation of radioactively safe ecosystems growth, their overload and degradation. All of this re- quires an inventory of ecosystem services by type, region, consumers, etc. and the formation of a state register of ecosystem services with a clear assignment of area of responsibility for appropriate natural ecosystems. This will help to make the economic evaluation of different ecosystem services and mechanisms of charges for ecosystem services.


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