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The long-lived trait is ecologically significant. Marlin and Swordfish can live for as long as 15 years, with breeding after 6 years. If they are overfished decreasing average age and shortage of breed stock will result, and fish stocks decline.

The situation is so serious for Bluefin Tuna that the fisheries are approaching collapse.

Effects of climate change on salt water fisheries

We have seen that overfishing is destroying fish-stocks. Climate change also plays a role. How? Growing CO 2 emissions mean that more greenhouse gasses CO 2 enter the atmosphere. Then about 1/3 of atmospheric CO 2 is taken up by oceans . Result: with more atmospheric CO2 the ocean becomes more acidic . This can become a serious issue in the life cycles of fish.

There are already dire predictions concerning the effects of increasing CO 2 in the atmosphere from fossil fuels, deforestation etc. This is especially serious for fisheries and the world’s poorest: 15% of their protein comes from fish.

The primary problem for fisheries arising from climate change that increases acidity in the world’s oceans is especially serious in the extreme southern and northern regions.

Recall from basic chemistry a lower PH number means more acidity in some ocean waters. A fall of one PH point represents a tenfold increase in acidity in some ocean waters. Vinegar, for example is quite acid. From the late 80s to 2012, acidity has increased from PH 8.11 to PH 8.06, largely as a result of higher atmospheric concentration of CO 2 .

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The fall of 0.5 points in PH in the last three decades represents a rise in ocean acidity of about 12%. Further, the best estimates suggest that there has been a 26% rise in acidity since 1820, when the industrial revolution began. The corrosive effect of rising ocean acidity on fisheries depends largely on how it affects aragonite. Aragonite is one of the forms of calcium carbonate. Coral reefs and virtually all mollusks (scallops, oysters, clams etc.) utilize much Aragonite in their skeletons. Omega is a number describing the threat of acidification to shellfish and coral. It depicts the aragonite saturation rate (see Figure 19-7). An Omega value of ONE is the critical level of acidity. Below a level of one , shells and skeletons made of calcium carbonate will dissolve.

Some sea animals, however, require a much higher omega level. Corals in particular require an omega level of 3 to grow their reef-making skeleton. Figure 19-7 shows that only relatively small portions of the Atlantic and Pacific are predicted to have omega levels>1.

In the mid-20th century near-pristine coral reefs hosted billions of fish, a favorite fish habitat. Ocean acidification is not the only reasons for the rapid decline of coral reefs worldwide. Deforestation in the Philippines, Thailand, Indonesia, Brazil and other nations has played a role as well. Growing deforestation leads to growing siltation of rivers. Ultimately this runoff reaches many coral reef formations in the ocean stifling reef growth. A final cause of coral reef decline has been dynamiting of reefs, where concussion from the explosions also kills fish on a large scale.

Questions & Answers

Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Economic development for the 21st century. OpenStax CNX. Jun 05, 2015 Download for free at http://legacy.cnx.org/content/col11747/1.12
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