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Effects of Climate Change:

Global temperatures have increased steadily in recent years creating predictions of a 1.5 to 4.5 degree Celsius increase in global temperatures in the next century which directly impacts ocean characteristics such as CO2 concentration, pH levels, oxygen levels and stratification. As temperatures increase, surface waters that are consistently warmed are not able to retain and hold as much dissolved gasses and nutrients as they would without this warming effect. An increase in atmospheric CO2 seen from climate change negatively impacts the pH of the ocean system by diffusing into the water and increasing the acidity (decreasing pH) which impacts many marine organisms. As polar regions experience atmospheric temperature increases, this indirectly increases the rate of evaporation which slowly increases the salinity of the surrounding surface water, introducing greater densities in the surface layer which decreases the stability of the water mass making it more likely to overturn.

Cephalopod Adaptations:

The increase seen in global temperatures can be detrimental to many marine species however many cephalopod species such as Dosidicus gigas, Todaropsis eblanae, Todarodes pacificus and Illex illecebrosus have showed positive population growth and an increase in organism range as a response to these climate change effects. Due to the cephalopods naturally shorter life spans and strong phenotypic plasticity compared to other marine species they are able to adapt to changing environmental conditions at a faster rate which gives them the ability to thrive in conditions that may be detrimental or cause harm to other species. In response to decreases in nutrients and dissolved gasses present in warmer waters, many cephalopod species are able to alter their reproductive needs, therefore altering their overall need for factors such as CO2, O2 and nutrients for energy. In these climate change conditions, cephalopods will often adapt by producing a larger amount of small offspring rather than fewer large offspring which increases the ability for these organisms to thrive by reducing their metabolic and energetic needs throughout their life cycle. The process of reducing offspring size allows the juveniles to require significantly less oxygen uptake and decreases the amount of energy spent through locomotion, hunting and feeding. The reduced need for certain dissolved gasses and nutrients allows cephalopods to thrive in harsh environments such as anoxic and H2S containing waters where other species would not be able to reproduce. In a study by Laptikhovsky, results showed that cephalopod species capable of surviving in anoxic or H2S containing waters showed a larger proportion and percent occurrence of small demersal offspring in comparison to large demersal offspring.

Expanded Range:

Species including Todaropsis eblanae and Illex illecebrosus have been seen travelling in northern latitude waters such as the North Sea in recent years and becoming permanent residents where they before would only migrate for spawning or foraging throughout the year. This increase in range of cephalopod species likely represents an overall global increase in the abundance and population density of these species which can be seen from the bycatch captured in commercial fisheries.