Oceanic waters shelter and nurture vast diversity of lives through delicate balance of light, temperature, depth, and nutrients. Comparatively, marine ecosystems are more prone to slightest changes in basic element of environment. Hence, the ongoing rise in sea surface temperature may be a early signs of future furry. So, let’s try to explore the possible impacts of sea surface temperature on biota.
Understanding sea surface temperature in space and time
There are huge seasonal variation in the degree of sea surface temperature in terms of depth and distance away from Equator. For more insight, let’s know the mechanism that either causes temperature to go up or down.
Role of specific heat capacity changing sea surface temperature
Scientifically, specific heat capacity of water is more than the capacity of landmass as the water is poor conductor of heat compare to landmass.
As a result, the degree of rise and fall in the temperature of water bodies is slow compare to landmass. Thus, the peak and trough of sea surface temperature is different from landmass.
Factors responsible for vertical distribution of sea temperature
In the oceanic waters, temperature and heat could hardly penetrate beyond 200 to 300 m from surface.
However, its degree may be vary in the continental shelf and abyssal plain. Due to land mass effect, oceanic water is more warm at the proximity of land compare to deepest open oceanic plains.
Apart from this, consideration of seasonal changes in the water temperature from place to place is indispensable, regarding marine or aquatic life.
In the summer or spring season due to longer duration of days, there is no dearth of light and temperature in the “Photic zone.” (upto 200m). Whereas, almost reverse happens when there is winter season in the either of hemispheres.
Ocean currents determining factor for sea surface temperature
As I mentioned that temperature in the marine environment is vary in space and time due to seasons, landmass, and latitudinal position.
Besides, it is the most vital determinant of density and salinity the two major properties of oceanic waters. It means that temperature affects both factors in positive correlation.
In summer in the either of hemispheres, when the temperature rises, density of sea water declines but salinity concentration increases with greater evaporation.
On the other hand, in winter all the phenomenon reverses. For details, take a look at the following analysis.
Ocean currents-heat balancing mechanism
Ocean currents are natural heat balancing mechanism of nature, flowing from higher temperature to lower and lower to higher. Accordingly, warm currents flow polewards, whereas cold in the direction of equator.
Upwelling and downwelling density difference
In case of density difference, denser water sinks, replacing lighter and vice-versa. For clearity, denser cold water from either of poles find its way to replace lighter in the tropical regions in the form of under-currents. Moreover, upwelling and downwelling are the direct outcomes of density differences.
Impacts of sea surface temperature on climate
If we look at the rainfall map of the world; then, we easily notice that there is a close relationship between sea surface temperature associated with either cold or warm current and degree of annual rainfall.
Spatially, deserts and cold currents association proves that the sea surface temperature have huge impact on regional climate.
Whereas, in case of warm currents, higher degree of rainfall is observed. That’s why we call it a major climatic factor.
Impacts of sea surface temperature on gases dissolveability
All the spheres including hydro, litho, bio, and atmosphere are interconnected. Likewise, atmospheric gases dissolve in the surface sea waters. But, its degree depends on the nature of temperature of the waters.
Gases dissolve in colder water than in warm
Scientificly, colder water is more favourable to dissolve more. Whereas, warmer water release more, instead to absorb.
In the winter season, waters remain colder.
So, these waters absorb more carbon dioxide and oxygen. On the other hand, opposite happens in the spring or summer season.
Technically speaking, gases are vital for aerobic animals and photosynthetic plants. In short, seasonal changes in the water temperature is very essential for photosynthesis, as well as survival of the aerobic organisms in the marine ecosystem.
Seasonal inter-mixing of sea water and nutrients cycle
Intermixing or upwelling and downwelling are attributed to the seasonal changes of sea water temperature.
In the winter, upwelling is observed in the tropical and sub-tropical regions.
Through this process, cold nutrients rich water mass replaces comparatively less denser.
Factually, cold water mass of the bottom is very rich in nutrients. As the Benthic part of the oceans continuously receives organic material of dead organisms.
And, while upwelling, it enriches surface waters in the winter season. Geographically, upwelling places are the best fishing grounds of the world like Grand bank George’s Bank.
Conversily, in summer season, with abundant sunlight and carbon dioxide, phytoplankton produces lots of food through photosynthesis for the rest of the animals. Definitely, this is the best epitome of nature’s babalancing act for its creatures
Impacts of rising sea surface temperature
Environmentally, marine organisms cannot bear even the slightest change in the normal level. Let’s see the negative impacts of rising sea surface temperature on entire biota.
Release of oxygen gase- a serious impact
As per the scientific community, oceans are the biggest storehouse of the atmospheric carbon. They absorb when there is a normal level of temperature as gases are more dissolveable in the cold water compare to warm.
With abnormal rising sea surface temperature, oceans release the absorbed gases in the atmosphere. Consequently, the chances of further rise in global temperature increases more rapidly.
Loss of oxygen man made disaster for aerobic animals
Truly, this is one of the most detrimental impacts of rising sea surface temperature. Because, the quantity of oxygen is already less in the sea waters. But, its importance for aerobic animals is beyond value. Deoxygenating water isn’t less than poison for these precious organisms.
Ocean acidification- one of potential impacts of sea surface temperature
Chemically, Ocean acidification is yet another negative impacts we usually noticed.
May be, you might have heard about the chemical reactions of carbonic acid with calcium carbonate.
In this process, carbonic acid transforms calcium carbonate into calcium bicarbonate which is easily dissolveable in the water, posing great threat for shell forming animals.
Then, shell forming animals such as corals, extract calcium dissolved in the water to form protective cover. Without this protective cover, these animals will become too vulnerable or will face danger of extinction.
Impacts of rising sea surface temperature on Coral reefs
Ecologically, corals are the reef building tiny polyps live in the big colonies in favourable oceanic waters.
For theirs survival, symbiotic relationship with Zooxanthellae is inevitable as the latter have photosynthetic pigment. In this way, corals receive 90 percent of food from this algae.
But, this algae cannot survive in the higher level of temperature. In the situation of higher temperature ,it becomes colourless and separates from corals.
In this way, we are not only losing precious corals reefs but also thousands of marine species bound to take shelter, due to rise in temperature.
Furthermore, the prediction of rising sea water level is also scaring. Hope it is a myth; Otherwise, the future of more than one billion would be in danger along rich rice belt to feed another billion.
Final thought on impacts of sea surface temperature
So far, we have learnt about the negative, as well as positive impacts of sea surface temperature on global climate as well as marine ecology. Logically, normal temperature is inevitable for the survival for many reasons, including survival of the marine biodiversity.
But, abnormal temperature will inflict irreparable damage. Today, we are witnessing just symptoms in the form of lethal cyclones, loss of species and coral bleaching. Sooner, we are going to be a spectator of trail of destruction if we fail to arrest human encroachment.
Interdependence Of Marine Organisms
Process of Coral reefs formation
Climate change causes and impacts
Tropical cyclones in Arabian sea