User:Meganwarren595/sandbox

Topic Evaluation

I believe addition to the diel vertical migration article would be appropriate given you are able to find a good number of references/resources. Jpethier (talk) 14:43, 13 October 2017 (UTC)jpethier

Article Evaluation

Fish Migration

The wiki article on fish migration contains relevant on topic information though some information appears to be missing. A section that addresses what triggers fish migration, and how they navigate from point A to point B may be appropriate in this article.

There are a couple of statements in this article that may be biased toward the fishery's perspective.

The information in the classification section of the article seems questionable, even though references are provided. The terms oceanodromous and potamadromous are still regularly used in fish biology, which is inconsistent with the information in the article. This is due to an outdated reference from 1949 about word usage that has changed since then. This issue was also brought up by another user on the talk page about the word amphidromous.

The article lead section lacks in text citations entirely while the remaining sections are not consistently cited at least once per paragraph. Reference 12 of the article is incomplete (?).

Examples of anadromous and catadromous fish species were brought up in a different paragraph from which these terms were defined in, this makes the article incoherent. The section of other examples is unorganized and could have been broken down and fleshed out into their own sub-headings.

This article belongs to two WikiProjects (Fisheries and Fishing, and Fishes) for which both have rated it a C for quality yet rated with high importance, though only six people have been active on the talk page making suggestions and edits.

The article gives a decent overview of the topic but there are many improvements to be made to get it up to standard.

Add to an Article

Poecilia reticulata

There is also the concept of color association to possibly explain the female mate choice since one of the food sources wild guppies compete vigorously for is the fruit of cabrehash trees, an orange carotenoid containing fruit.The orange coloration the female guppies select for in males is composed of carotenoids the saturation of it is effected by the amount of carotenoid as well as his parasite load. These fish cannot synthesize these pigments their selves and must obtain them through their diet, because of this connection, females are selecting for healthy males with superior foraging abilities by choosing mates with bright orange carotinoid pigments, thus increasing the survival chance of her offspring.

Potential Topics

• Fish Migration - would benefit from a section on vertical migration.
• V Formation - has no information about leading and following times of birds and their cooperation.
• Structures built by animals - does not mention swiftlets in the self secreted materials section. There are multiple other pages that mention the edible-nest swiftlets but there is no mention here.
• Moose - no section that elaborates of their behavior during the rutting season, social structure and reproduction section very brief.
• Supernormal stimulus - does not mention supernormal stimulus exploitation used by brood parasites like cuckoos.

Drafting my article

Diel vertical migration

The page on vertical migration provides a basic understanding but there is much work to be done on it. The article requires more examples of organism that partake in this form of migration, and need references as well as more in depth explanations of the stimuli. I will organize the page by separating the stimuli and types of vertical migration and add additional information such as circadian clocks as a stimulus, how events like midnight sun effect vertical migrations that are primarily dependent on light intensity, and other novel types of vertical migration like reverse diel vertical migrations and assents in early morning. The article would benefit for better fleshed out explanations of stimuli, types, and reasons for vertical migration.

Peer review - MegFrank

Your potential topics section looks like you have a good plan for making the article better. For the breakdown of the article, do you plan to use each topic as a new section, or use topics such as "circadian clocks" as your topic, and break it down from there? Best of luck with editing, I look forward to seeing your contributions!

Peer Review Response

Thank you both for the feedback, I do appreciate it! I believe that following the layout of the existing article will certainly help guide my contributions. When it comes to the article breakdown, my topics of interest will either fall under an existing section or require a new one be created. For example my input on circadian clocks can easily be included under the types of stimuli section; whereas, the special incidence of midnight sun and its effects on vertical migration will require the creation of a new heading in the article as it does not fit any of the existing. Perhaps I will include a section about factors that effect vertical migration so I can explain the midnight sun effects and the causes of the novel types of vertical migration that occur in the same section. I will do my best to see that all these piece fall into their proper place as I continue with the editing!

Diel Vertical Migration

Diel vertical migration (DVM). This form of migration is not restricted to any one taxa as examples are known from crustaceans (copepods), molluscs (squid), and ray-finned fishes (trout). There are various stimuli responsible for this phenomenon, the most prominent being response to changes in light intensity, though evidence suggests that biological clocks are an underlying stimulus as well. There are a number of potential reasons to explain the phenomenon in nature, though it is most typically to access food and avoid predators. While this mass migration is typically nocturnal, with the animals ascending from the depths at nightfall and descending at sunrise, novel types of vertical migration can occur in response to the different cues and stimuli that trigger migration. Some novel events include the absence of DVM during midnight sun in Arctic regions and the sudden onset of migration due to a solar eclipse.

Discovery

While performing sound propagation experiments the University of California's Division of War Research (UCDWR), consistently had results of the echo-sounder that showed a distinct reverberation that they attributed to mid-water layer scattering agents, there was speculation these readings may be attributed to enemy submarines. By collaborating with biologists from Scripps Institution and the UCDWR, they were able to confirm that the observed reverberations from the echo-sounder were in fact related to the diel vertical migration of marine animals. The DSL was caused by large, dense groupings of organisms, like zooplankton, that scattered the sonar to create a false or second bottom.

Types of vertical migration

Diel

This is the most common form of vertical migration. Organisms migrate on a daily basis through different depths in the water column. Migration usually occurs between shallow surface waters of the epipelegic zone and deeper mesopelagic zone of the ocean or hypolimnion zone of lakes.

Furthermore, there are three recognized types of diel vertical migration. This includes nocturnal vertical migration, the most common form where organisms ascend to the surface around dusk remaining at the surface for the night then migrating to depth again around dawn. the second form is reverse migration, which occurs with organisms ascending to the surface at sunrise and remaining high in the water column throughout the day until descending with the setting sun. The third form is twilight diel vertical migration that involves two separate migrations in a single 24-hour period, with the first ascent at dusk followed by a descent at midnight, often known as the "midnight sink". The second ascent to the surface and descent to the depths occurs at sunrise.

Seasonal

Seasonal changes to the environment may influence changes to migration patterns. Normal diel vertical migration occur in species of foraminifera throughout the year in the polar regions; however, during the midnight sun, no differential light cues exist so they remain at the surface to feed upon the abundant phytoplankton, or to facilitate photosynthesis by their symbiotes.

Ontogenetic

There are often pronounced differences in migration patterns of adult female copepods, like Eurytemora affinis, which stay at depth with only a small upward movement at night, compared to the rest of its life stages which migrate over 10 meters. In addition, there is a trend seen in other copepods, like Acartia spp. That have an increasing amplitude of their DVM seen with their progressive life stages. This is possibly due to increasing body size of the copepods and associated risk of visual predators, like fish, as being larger makes them more noticeable.

Vertical Migration Stimuli

There are two different categories of factors that are known to stimulate vertical migration, endogenous and exogenous. Endogenous factors originate from the organism itself; sex, age, biological rhythms, etc. Exogenous factors are environmental factors acting on the organism such as light, gravity, oxygen, temperature, predator-prey interactions, etc.

Endogenous factors

Endogenous rhythm: Biological clocks are an ancient and adaptive sense of time innate to an organism that allows them to anticipate environmental changes and cycles so they are able to physiologically and behaviorally respond to the expected change. Evidence of circadian rhythms controlling DVM, metabolism, and even gene expression have been found in copepod species, Calanus finmarchicus. These copepods were shown to continue to exhibit these daily rhythms of vertical migration in the laboratory setting even in constant darkness, after being captured from an actively migrating wild population.

Clock gene expression: Many organisms including the copepod C. finmarchicus, has genetic material devoted to maintaining its biological clock. The expression of these gene varies temporally with the expression significantly increasing following dawn and dusk at times of greatest vertical migration seen in this species. These finding may indicate they work as a molecular stimulus for vertical migration.

Body size: The relative body size of an organism has been found to effect DVM. Bull trout express daily and seasonal vertical migrations with smaller individuals always staying at a deeper layer than the larger individuals. This is most likely due to a predation risk but is dependent on the individuals own size such that smaller animals may be more inclined to remain at depth.

Exogenous factors

Light: Light is the most common and critical cue for vertical migration.

Temperature: Organisms will migrate to a water depths with suitable temperatures that best suit the organisms needs, for example some fish species migrate to warmer surface waters in order to aid digestion. Temperature changes can influence swimming behavior of some copepods. In the presence of a strong thermocline some zooplankton may be inclined to pass through it, and migrate to the surface waters, though this can be very variable even in a single species. The marine copepod Calanus finmarchicus will migrate through gradients with temperature differences of 6°C over George's Bank; whereas, in the North Sea they are observed to remain below the gradient.

Salinity: Changes in salinity may promote organism to seek out more suitable waters if they happen to be stenohaline or unequipped to handle regulating their osmotic pressure. Areas that are impacted by tidal cycles accompanied by salinity changes, estuaries for example, may see vertical migration in some species of zooplankton.

Pressure: Pressure changes have been found to produce differential responses that result in vertical migration. many zooplankton will react to increased pressure with positive phototaxis, a negative geotaxis, and/or a kinetic response that results in ascending in the water column. Likewise, when there is a decrease in pressure, the zoo plankton respond by passively sinking or active downward swimming to descend in the water column.

Predator kairomones: This may stimulate the prey to vertically migrate to avoid said predator. The introduction of a potential predator species, like a fish, to the habitat of diel vertical migrating zooplankton has been shown to influence the distribution patterns seen in their migration. For example, a study used Daphnia and a fish that was too small to prey of them (Lebistus reticulatus), found that with the introduction of the fish tot the system the Daphnia remained below the thermoclline, where the fish was not present. This demonstrates the effects of kairomones on Daphnia DVM.

Tidal Patterns: Some organisms have been found to move with the tidal cycle. A study looked at the abundance of a species of small shrimp, Acetes sibogae, and found that they tended to move further higher in the water column and in higher numbers during flood tides than during ebb tides experiences at the mouth of an estuary. It is possible that varying factors with the tides may be the true trigger for the migration rather than the movement of the water itself, like the salinity or minute pressure changes.

Novel Events

Due to the particular types of stimuli and cues used to initiate vertical migration, there can be sudden anomalies that change the pattern drastically.

For example, the occurrence of midnight sun in the Arctic induces changes to planktonic life that would normally perform DVM with a 24-hour night and day cycle. In the summers of the Arctic the Earth's north pole is directed toward the sun creating longer days and at the high latitude continuous day light for more than 24-hours. Species of foraminifera found in the ocean cease their DVM pattern, and rather remain at the surface in favor of feeding on the phytoplankton, for example Neogloboquadrina pachyderma, and for those species that contain symbionts, like Turborotalita quinqueloba, remain in sunlight to aid photosynthesis.

There is also evidence of changes to vertical migration patterns during solar eclipse events. In the moments that the sun is obscured during normal day light hours, there is a sudden dramatic decrease in light intensity. The decreased light intensity, replicates the typical lighting experienced at night time that stimulate the planktonic organisms to migrate. during an eclipse, some copepod species distribution is concentrated near the surface, for example Calanus finmarchicus displays a classic diurnal migration pattern but on a much shorter time scale during an eclipse.