Intensification of open-ocean oxygen depletion by vertically migrating animals
Oxygen is a very important gas that is needed by all living organisms for the the purpose of respiration. It is, therefore, in the interest of everyone to understand the conservation and the significance of oxygen in an ecosystem (Daniele Bianchi, 2013). The research aimed at studying the dieL vertical (DVM) migration of the zooplankton within the depth ranging from the surface to the mesopelagic levels of the ocean water (Vinogradov, 1968).As a result, the focus was placed on determining the fluctuations in amounts of carbon accompanying the respiration of the marine organisms at varying times. To obtain data on the depths of the DVM, information from the Doppler profilers from 1990 to 2011 were used. These data were quite reliable as they revealed the changes in the level of the depths of the zooplanktons that were fluctuating from time to time.
However, there were certain arguments that the intensity of sunlight has a great bearing on the amount of oxygen that was found to be concentrated at different depths of the diel ocean depths. These arguments were nevertheless challenged by the fact that, at low depths, the oxygen available is sufficient enough to support the lives of smaller organisms unlike the large predators that would need higher amounts of oxygen supply to survive at low levels (Hernandez-Leon, 2005). In fact, this was in conformity to the hypothesis that the low oxygen supply at lower depths provided protection to small organisms against the predation by the large organism.
Besides, better predictors were determined through a statistical analysis. Some of these include the surface chlorophyll, mixed-layer depths and temperature gradients. Data on these variables were obtained from the vertical migration based on the global monthly climatological data sets. In addition, the link between active export of organic matter by the migrating animals and the corresponding oxygen consumption was studied using a pair of ocean model and biochemistry model. The assumption made while using this model was that DVM export was a constant ratio of particle production obtained from data-based multiple linear regression (Hernandez-Leon, 2005).
After the analysing the results from the integration of the models after a study period of 100 years, it was found that oxygen consumption by the migrating animals was linearly dependent on the active export fraction of organic matter released by them at a particular location. In addition, the research also found that, at lower migration depths, there is significantly high level of oxygen consumption and respiration (Hernlund, 2013).
In their conclusion, the authors inferred that DVM has a significant influence on the spatial properties and intensity of oxygen. The study also reiterated the significance of DVM on oxygen consumption at all ocean depths and further directed that constraints as divisions of export of organic matter between the active migrators and passive sinking animals’ metabolic reliance on oxygen and their altered respiration rates in oxygen minimum zones be considered in future researches.
This research is very significant as it offers a detailed knowledge on the DVM with its globally mapped relevant data available as well as those based on observations. Owing to the fact that aquatic organisms are vulnerable part of the ocean ecosystem, an understanding of the varying characteristics under changing conditions is very ideal. The research clearly reveals the variations at the two ocean depths in relation to oxygen consumption. Moreover, it is quite evident that the animals that undergo DVM have a direct influence on the food webs in the oceanic ecosystem (Vinogradov, 1968). Therefore, an insight into the biological processes within the ocean is a prerequisite for successful study of the ocean structure.
It is worth mentioning that fluctuations in the levels of oxygen and carbon dioxide in the ocean contributes that are currently experienced world problems such as global warming. DVM can, therefore, not be perceived as trivial (Steinberg, 2013). Data obtained on the DVM augments the visualization of the varying regional patterns as vividly shown in Fig. 2. It is evident that The Pacific and Atlantic Oceans regions of deeper migrations correspond with their warmer sea surface temperatures and currents (Trujillo & Thurman, 2011) while the converse holds for coastal parts of the Americas and Africa which are subjected to colder northern and eastern boundary currents of the subtropical gyres.
Precisely, the effect of vertical water movement, particularly in the case of localised upwelling and/or down welling, on animals during the course of their daily migration was not addressed in the study (Hernlund, 2013). Perhaps it was because there impacts were trivial compared to that brought about by the warm currents.
All the same, a better understanding on the effect of animals’ migratory pattern on particle dynamics, plausible if the ocean surface currents and prevailing winds which result in these vertical processes despite the lack of strong correlations observed in the study are considered.
In a nutshell, it can be concluded that a comprehensive study of Diel vertical migration, coupled with the negative impact of global warming faced by vulnerable marine organisms, would inevitably lead to more insightful discussion of the highly interactive atmosphere-ocean system at both its' localised micro and regional macro levels (Steinberg, 2013). The relevant course topic content which has been applied to this discussion includes ocean circulation and climate change. This study alerts us to yet another vulnerable group of the ocean living habitat which can be threatened by human-caused global warming and urges us to take additional measures to reduce its unprecedented climate-altering aftermaths (Vinogradov, 1968).
References
Daniele Bianchi, E. D. (2013, July 9). Intensification of open-ocean oxygen depletion by vertically migrating animals. Nature geoscience.
Hernandez-Leon, S. &. (2005). Respiration in Aquatic Environment. London: Oxford Univ. Press.
Hernlund, J. (2013). Mantle fabric unravelled. Natuer Geoscience , vol.6.
Steinberg, S. C. (2013, July). Marine Biogeochemistry. Nature Geoscience, vol 6.
Vinogradov, M. (1968). Vertical Distribution of the Oceanic Zooplankton. Manchester: Nauka.
