Swimming in Climate Change

Climate Change and Marine Life – Final Draft

Why Care?

Global warming, climate change. I know that when I hear terms like these, I think of the affects they have on our habitat: solid ground.  But the ocean is actually one of the main components of humans’ survival – ocean plants produce half of the world’s oxygen, and absorb 1/3 of the carbon dioxide we produce, making the oxygen easily accessible.  We also get weather from the ocean, whether we live near it or not; through the water cycle, the ocean gives us clouds that block or allow heat to pass through, adjusting temperature, and produce precipitation – let alone fresh water.  Then there’s food; seafood, of course, but along with this, ingredients like algae that are used in so many of the products we consume.  So, to sum all of those statistics up, we really do need the ocean.  I am extremely unscientific so apologies to all of you who know this as common knowledge; I knew that the ocean’s purpose went deeper than scenic views, but in which direction I had no clue.  In return for all that it gives us, we have the responsibility of caring for it; the quality of the water and therefore the plant and animal life.  This is why, in all of this global warming talk, we need to remember the ocean and how it and its inhabitants are being effected by climate change.

How Climate Change is Affecting Marine Life

“The top ocean predators in the North Pacific could lose as much as 35% of their habitat by the end of the century as a result of climate change”, writes Juliet Eilperin in response to a study published in the Nature Climate Change journal.  The study that Eilperin is referring is one where Canadian and American researchers, over the past decade, tracked 4,300 ocean animals, of 23 different species, mainly in the North Pacific area, and discovered that climate change could destroy many marine animals’ habitats and possibly their species itself.  The North Pacific area is a Transition Zone, which means that cold and warm waters come into contact here.  The dotted lines in the image below show where this area is:

© 2012 The Earth Times

This study sparked many questions in me, mainly, how? How could climate change really affect marine life thousands of feet below us? So, after doing a little research, I came up with some useful information that helped me understand; I hope it helps my readers also!

With the UN Intergovernmental Panel on Climate Change‘s predictions of global temperature increase of 1.8 to 10.8 degrees by 2100, this transition zone could move 600 miles north throughout the majority of seasons as colder waters will be pushed from the equator (warmer waters will ultimately be “taking over”).  Graphs a and b show the past decade’s sea-surface temperature (SST), and the predictions for change.  Notice that the ‘high’ temperatures are moving North.  The graphs I’ve used all come from the Nature Climate Change study; I’ve just tried to infer and explain them in not-so-sciencey language!

© 2012 Nature Publishing Group

This change means that as the polar waters move further north, the chlorophyll (the green pigment needed for photosynthesis) will essentially move with it, as the greatest chlorophyll concentrations are in cold polar waters.  So, at the geographical location of the North Pacific Transition Zone now, the amount of chlorophyll will decrease as the zone (point of contact of cold and warm waters) moves North.  Graphs b and c show the past decade’s Chlorophyll a, (Chl-a) and the predictions for change (chlorophyll a is just a specific form of chlorophyll).  Notice that the chlorophyll is moving North and areas in graph c, plentiful in chlorophyll, have quite little in graph d.

© 2012 Nature Publishing Group

Now, since plants will not grow without chlorophyll, the plant growth in this location will also decrease significantly, cutting marine animals off from a major food source.  And this leads to the conclusion; most marine animals are going to move as far as the North Pacific Transition Zone does, in order to follow the plant life, the food; seabirds and sharks, for example, target high-chlorophyll waters and will therefore be among the many species that migrate themselves and their future habitats.

Graphs a to d show the quarterly trends of the amounts of animals in the past decade, and graphs e to f show the predicted change.  Notice that the high concentration of species moves North, and that the area that was dense in marine population during the past decade will be quite empty in the future.

© 2012 Nature Publishing Group

Affects on the Animals

Many animals will mostly lose their habitat in the climate-inspired move and therefore decrease in population; as conditions in the North will not be the same, and their adaptation ability differs.  Some reasons species would lose their habitats are bolded, below, with examples of the animals that the cause would affect.

Narrow Temperature Range

– sharks

– salmon

Specialized Diets (less ability to adapt and therefore population decrease)

– blue whales

– leatherbacks

Some animals, on the other hand, will not only survive, but likely increase in number due to the lack of predators and ability to adapt.  These animals include:

– tuna

– seabirds

– pinnipeds (fin-footed marine animals such as seals or walruses)

Animals have an effect on the other animals around them also, for example, if certain species depopulate, this will confuse the marine food chain and result in even more depopulation, due to lack of food; Eiperlin writes that from California to Japan, we could lose up to 20% of species diversity.

Affects on Humans

The North Pacific Transition Zone shift will affect humans mostly in a negative way: for example, fisheries will have to relocate and travel further for product, ultimately using more energy and causing the climate to get warmer still, eventually coming back to ocean temperature, marine life, and then humans as a result.  Again, if certain species depopulate, this will confuse the marine food chain which really, we are a part of.  With decreasing marine life, we will need to search harder for it and destroy certain ecosystems in the process, for example, scraping seabed to get as many fish out of an area as possible.  An uncontrollable food chain will result in a completely imbalanced marine ecosystem which will therefore suffer.  And really, once the ocean goes, we go, as we rely on the ocean for our own survival.  But, this is one extreme, not too possible in the near future.  Areas other than the North Pacific could stay completely unaffected, like the current that runs along the west of North America: the California Current.  Here, the rising of cold polar waters will continue and for the most part stay in one place.  So, while the affects of climate change on marine life could definitely lead our planet in a negative direction, I say that this possible negative direction is not what we need to be worrying about right now.  I think we need to be concerned about the present, not preventing change but monitoring it.  This does not, however, mean that we can forget about the future altogether.  What we need to have is balance; it the best way we can achieve sustainable development. Elliott L. Hazen, in the study Predicted habitat shifts of Pacific top predators in a changing climate, speaks of this present-future balance, of acting and planning future actions: “management strategies and reserves need to be based not only on present biodiversity distributions and migration corridors but also on their persistence in the future… Climate change is a broad-scale and directional process and we must plan accordingly to ensure our healthy and functioning ecosystems remain intact, and recovery efforts are appropriately targeted and successful.”