Adaptations of organisms in extreme ecosystems; Desert, Arctic, and Benthic Biomes

1. Adaptations of organisms in extreme ecosystems; Desert, Arctic, and Benthic Biomes MareePascall, ZoologyRickey Smith, Human BiologySarah Uzzell, Textile Technology Benthic Habitat Abstract • Scientists examined the metabolic rates of deep-sea fish, and how these rates are affected by factors such as temperature of the environment and body mass of the organism. The “visual-interactions hypothesis” provided a possible explanation for these effects. Using data collected by themselves, as well as 66 other studies, Drazen and Siebel interpreted that fish occupying the benthic and benthopelagic zones do indeed have lower metabolic rates than do species in more shallow water (Drazen et al 2007). • Another study investigated how the changes in the biochemistry of the upper ocean affected the benthic community. This work examines the link between the diet of holothurians and their ovarian carotenoid biochemistry. After analyzing the gut contents they determined that certain necessary compounds fluctuate between years and location with a direct correlation to the supply from the upper ocean organisms. These results are significant because an important connection between the upper and lower zones of the ocean is apparent (FitzGeorge-Balfour et al 2010). • An investigation into bioluminescence of organisms of the sea was conducted. Overall the scientists found that bioluminescence was the most prevalent means of communication between organisms. Its efficient and transmissible nature is important due to the limited food sources, light, and extreme conditions which require these lower metabolic rates and not much excess energy. These results are significant because they show how organisms can utilize one function such as bioluminescence in a variety of ways (Haddock et al 2010). • In another study a possible correlation between temperature preference and stress response to hypoxic environments in cod with different blood type was looked at. Scientists in this study simulated various conditions to expose Atlantic cod and monitored the reactions of the fish with each type of haemoglobin Hbl-1 and Hbl-2. The results seemed to indicate that Hbl-2 cod are more tolerant to stressors of hypoxia and temperature change that are Hbl-1. The encompassing conclusions show how fish occupying zones with differing conditions have adapted slightly different mechanisms for survival than organisms in the same species (Methling et al 2010). These graphs represent data form the Cocooning frog Cycloranaplatycephala A) Mass lost as compared to that of initial mass. Asterisk correspond to points that are statistically significant from points as 3 month mark. B) Plasma and urine osmolalities over the 15 month time frame. Due to the fact that the osmolalities only reached equal amounts that the end of the experiment, it is interpreted to show that these frogs could survive much longer times in this aestivation state. Asterisk showing urine osmolalities significantly lower than plasma values. C) Hematocrit levels for control (0 months of aestivation) and aestivating frogs. The drop in hematocrit is not alarming due to the correlating drop in metabolism making oxygen less vital in large quantities. Asterisks mark significantly difference from control frogs. The human population is growing and expanding into ecosystems that are exotic and extreme. With environmental obstacles, such as pressure, temperature, absence of sunlight, and hypoxic oxygen levels, how are we to survive in these environments that show such barriers to life? Species within desert, benthic, and arctic biomes have created adaptations to live in these habitats and we can learn from these traits. Through the process of observation and dissection of different species, we have discovered some of the ways that animals and plants alike have learned to survive in extreme environments. Desert animals have found unique ways to obtain water. Some amphibians and reptiles sequester water from their bladder to remain hydrated. The red fox chooses water rich foods to replace energy content when water is low. Lipids under the skin/cuticle are used by birds and scorpions to reduce water loss. Benthic dwelling creatures have acquired mechanisms to survive in the extreme conditions of the subphotic zones of the ocean. Such mechanisms allow them to thrive in hypoxic and high pressure conditions. Similarly arctic plants have evolved to develop mechanisms that prevent death or injury when temperatures get dangerously low. The plants have developed over time, and have gained the ability to know when to stop growth development and prepare for freezing temperatures. This knowledge about plants has also helped scientists develop new anti-freezing methods. There are enormous amounts of information to be learned from these creatures, and the applications of this knowledge are far reaching and needed Introduction In each of the environments presented here, organisms have learned to adapt to the extreme conditions that are imposed on them. In the desert, the earth is high in salt content, and rainfall is minimal. This leads to a problem of how to retain water and use it sparingly. Evaporative, respiratory, and cutaneous water loss are all ways that water is lost by animals. In the arctic, the ability of a plant to survive in freezing temperatures is based on genes and physical make up. Some plants have antifreeze components allowing them to survive in much colder temps than other plants. At the deepest depths of the ocean, where pressures are high and light cannot reach, animals have created ways to communicate and survive. Low metabolic rate (decreasing oxygen use) and bioluminescence allow these creatures to thrive in this dismal abyss. How these animals achieve such success given their stressful environments is a growing area of interest in science. These graphs show the energy (white) versus the water (black) intake of the Desert Red Fox of Djerba given the habitat it lives in. The top graph shows how in the arid regions, water rich prey items are consumed more due to lack of water in the environment. This is switched for the less arid regions. The bottom graph shows this energy/water distribution based on the type of habitat. In grasslands and suburban areas, water is more readily available due to wells, farms and human access to water. This allows the fox to choose energy rich foods. Conclusions • Within the desert, benthic and arctic ecosystems of this world, many organisms have found ways to survive in unique ways. In a xeric environment, animals control water loss given high salinity of their surroundings and the period of drought being great. In the tundra, plants have genes that allow for seedlings to remain viable even in extreme cold. The deep sea animals utilize bioluminescence as a key factor in communication when there is no presence of sunlight at these depths. All of these adaptations, along with many others, make these creatures remarkably suited for their given habitat. With thousands of organisms inhabiting these ecosystems, each with a unique adaptations to survive, how can we ignore the chance to study these characteristics and learn from them. The applications of antifreeze used by arctic plants has been utilized as well as the idea that the smaller the volume an object carries, the more effective it is for deep sea diving (seen in research submarines that collect data at great depths). What other adaptations can we apply to our own betterment? These animals and plants should be continued to studies so that we ourselves could learn how to explore and survive in ecosystems that appear uninhabitable and extreme. Desert Ecosystem Arctic Biome • Two studies were conducted to examine the ability of Cocooning Frogs and Gila Monsters to sequester water from their bladders during extreme drought. Measurements were taken on the cocooning frogs for 15 months to determine mass loss, osmolalities, and AVT concentrations. At three month intervals (excluding month six), a group of frogs was dissected, masses were weighed after removal of urine, oxmolyte concentrations were measured from the urine, and AVT was quantified. It was found that these animals could survive much longer than the 15 month study period by using the bladder as a reservoir (Cartledge et al 2008). • The Gila Monster bladder was tested for permeability by utilizing radioactivity of plasma, and observing rate of dehydration of two groups of lizards showed that the bladder was indeed used for regulatory purposes. For up to 80 days, it was proven that these large lizards could maintain a steady osmolality given the absence of water during drought (Davis et al 2007). • A desert house sparrow and a desert scorpion both utilize the lipid bilayer present under the skin or cuticle to reduce evaporative water loss (EWL) in the dry environment of the desert. Saudi Arabian sparrows were studied through comparison with Ohio fledglings for developmental differences in tolerance to humidity. The genetic and plasticity origins were both investigated and it was found that desert sparrows and Ohio sparrows used different methods of lipid control, but achieved the same result of lowered cutaneous water loss (CWL) (Munoz-Garcia et al 2008). • Scorpions were tested for lipid composition at varying temperatures and were found to use the lipids as a water proofing material and achieved a much lower EWL rate than other arthropods of similar size, showing the adaptive strategy of the scorpions to be ideal (Gefen et al 2009). • In Djerba, the red fox survives in three distinct habitats in two types of environments by choosing food sources accordingly. By looking at vegetation patchiness, food source abundance, and comparing these to the region of inhabitation, it was found that these foxes do indeed consume more insects, high in water content, when in a dry, arid region. Figs were consumed in higher proportions when water was more readily available and energy consumption could be taken advantage of (Dell' Arte et al 2009). • Old photos of arctic areas were compared to photos that were taken within the last 4 years. • The environmental conditions that cause a plant to stop growing and go into dormancy were examined. The change in gene expression in plants was measured. The plants’ adaptation to cold via antifreeze proteins was observed. • The effects of doing experiments in a laboratory setting compared to doing them in a natural environment were noted. • There was a lot of growth in the Arctic areas. Areas that did not have vegetation previously had smaller greenery, while the areas that had growth previously, had larger shrubs and trees The amount of biomass had increased by a large amount External Stress factors were the main cause of plants going into dormancy mode. • A shortening of the plants photoperiod, and a consistent drop in temperatures were the two main triggers for dormancy. • It was noted that certain plants that were not able to withstand colder temperatures had the ability to express a gene that allowed the plants seedlings to remain viable. It was observed that antifreeze proteins helped significantly with plants being able to handle the cold. • It was noted that there are various levels of cold hardiness that plants can undergo. It was also noted that if the temperature dropped too fast, the plants would experience “Cold shock” References Cartledge, V. A., Withers, P. C., & Bradshaw, S. D. (2008). 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