Al-Chemist Ungu

because chemistry is true and this just for you

MSDS ASAM NITRAT

MSDS ASAM NITRAT
Oleh :
Wahyu Fajaryanto 09303241007
Nurul Kurniati Rahayu 09303241012
Eko Budiyanto 09303241027
Astri Ani 09303241035
  1. Pendahuluan

MSDS (Material Safety Data Sheet) merupakan kumpulan data keselamatan dan petunjuk dalam penggunaan bahan-bahan kimia berbahaya.  Lembar data keselamatan bahan didesain sedemikian rupa, disusun secara ringkas , skematik dan dalam bahasa indonesia agar mudah dimengerti dan dipahami. Pembuatan LDKB ini dimaksudkan sebagai informasi acuan bagi para pekerja dan supervisor yang menangani langsung dan mengelola bahan kimia berbahaya dalam industri maupun laboratorium kimia. Dengan informasi tersebut diharapkan seseorang akan mempunyai naluri untuk mencegah dan menghindari, serta mampu menanggulangi kecelakaan kimia yang mungkin terjadi (Tim Supervisi Ditjen Dikti, 2002). Informasi dalam LDKB ini bukan untuk menakut-nakuti, melainkan mendorong sikap kehati-hatian dalam menangani bahan kimia berbahaya.
LDKB bukan merupakan terjemahan dari MSDS dari luar negeri, tetapi merupakan kumpulan informasi keselamatan dari banyak buku, leaflet, jurnal, dan pengalaman (http//www.kimianet.lipi.go.id/database.cgi?depandatabase&&&1&1098595676).
  1. Cara Memahami LDKB maupun MSDS
  1. Identifikasi bahan, bagian ini menjelaskan nama bahan kimia, meliputi :
  1. Nomor urut LDKB
  2. CAS (Chemical Abstract Services)
  3. Sinonim baik nama kimia maupun nama dagang
  4. Rumus Dan Berat Molekul
  1. Label bahaya keselamatan, diberikan dalam bentuk gambar, ada ranking bahaya 0-4 (label NFPA, Amerika) yang mempunyai arti :

Angka 4 : Penyebab kematian, cedera fatal meskipun ada pertolongan. Segera menguap dalam keadaan normal dan dapat terbakar dalam keadaan cepat. Mudah meledak atau diledakkan, sensitif terhadap panas dan mekanik.
Angka 3  : Berakibat serius pada keterpaan singkat, meskipun ada pertolongan. Cair atau padat dapat dinyalakan pada suhu biasa. Mudah meledak, tetapi memerlukan penyebab panas panas dan tumbukan kuat.
Angka 2  : Keterpaan intensif dan terus menerus berakibat serius, kecuali ada pertolongan. Perlu sedikit ada pemanasan sebelum bahan dapat dibakar. Tidak stabil, bereaksi hebat, tetapi tidak meledak.
Angka 1 :  Penyebab iritasi atau cedera ringan. Dapat dibakar tetapi memerlukan pemanasan terlebih dahulu. Stabil pada suhu normal, tetapi tidak stabil pada suhu tinggi
Angka 0  : Tidak berbahaya bagi kesehatan meskipun kena panas (api). Bahan tidak dapat dibakar sama sekali. Stabil, tidak reaktif, meskipun klena panas atau suhu tinggi.
  1. Informasi bahan singkat mengenai jenis bahan, wujud, bahaya, serta manfaat nya. Dari informasi singkat dan label bahaya , secara cepat dapat dipahami kehati-hatian dalam menangani bahan kimia tersebut.
  2. Sifat-sifat bahaya
  1. Bahaya keselamatan : Bahaya terhadap kesehatan dinyatakan dalam bahay jangka pendek (akut) dan jangka panjang (kronis). NAB (Nilai ambang Batas) diberikan dalam satuan mg/m3 atau ppm. NAB adalah konsentrasi pencemaran dalam udara yang oleh dihirup seseorang yang bekerja selama 8 jam/hari selama 5 hari. Beberapa data berkaitan dengan bahaya kesehatan juga diberikan yaitu :
  1. LD-50 (lethal doses) : dosis yang berakibat fatal terhadap 50% binatang percobaan mati.
  2. LC-50 (lethal concentration) : konsentrasi yang berakibat fatal terhadap 50% binatang percobaan.
  3. IDLH (immediately dangerous to life and health) : pemaparan yang berbahaya terhadap kehidupan dan kesehatan.
  1. Bahaya kebakaran
Ini termasuk kategori bahan mudah terbakar, dapat dibakar, tidak dapat dibakar atau membakar bahan lain. Kemudahan zat untuk terbakar ditentukan oleh :
  1. Titik nyala : suhu terendah dimana uap zat dapat dinyalakan
  2. Konsentrasi mudah terbakar : daerah konsentrasi uap gas yang dapat dinyalakan. Konsentrasi uap zat terendah yang masih dapat dibakar disebut LFL (low flammable limit) dan konsentrasi tertinggi yang masih dapat dinyalakan disebut UFL (upper flammable limit). Sifat kemudahan membakar bahan lain ditentukan oleh kekuatan oksidasinya.
  3. Titik bakar  : suhu dimana zat terbakar dengan sendirinya.
  1. Sifat – sifat fisika  : merupakan faktor yang dapat mempengaruhi sifat bahaya suatu bahan
  2. Keselamatan dan pengamanan : penanganan dan penyimpanan, tumpahan dan kebocoran , pertolongan pertama, pemadam api.
  3. Informasi lingkungan : menjelaskan bahaya terhadap lingkungan dan bagaimana menangani limbah atau buangan bahan kimia baik berupa padat, cair maupun gas (www.kimianet.lipi.go.id).
  1. MSDS HNO3
  1. Identifikasi Produk


Nama Produk : Asam Nitrat 65 %
Kode Katalog : SLN2161
CAS# : Campuran
RETCS : Tidak Dipakai
TSCA : TSCA 8 (b) persediaan: Air, Asam nitrat, marah
CI # : Tidak dipakai.
Sinonim : Nitric Acid 65%
Nama Kimia : Tidak dipakai.
Rumus Kimia : Tidak dipakai.
  1. Komposisi Bahan
Nama
CAS#
% massa
Air
7732-18-5
35
Asam Nitrat, furning
7697-37-2
65


Data  Toksikologi pada Bahan : Asam nitrat, berasap : UAP (LC50): akut 244 ppm [Rat]. 344 ppm 0.5 hours [Rat]
  1. Identifikasi Bahaya
  • Potensi Efek Kesehatan Akut
Sangat berbahaya jika terjadi kontak langsung dengan kulit (korosive, iritatif), kontak dengan mata (korosive, iritatif), gangguan pencernaan dan gangguan pernafasan. Dalam bentuk cairan atau spray bisa menyebabkan iritasi mata
  • Potensi Efek Kesehatan Kronis
Efek karsinogenik : tidak ada
Efek mutagenik : tidak ada
Efek teratogenik : tidak ada
Senyawa ini dapat meracuni paru-paru, membran mukosa, sistem pernafasan bagian atas, kulit, mata, dan gigi. Jika terlalu lama atau berulang-ulang terkena, maka dapat menyebabkan kerusakan organ tubuh. Jika terlalu lama mengalami kontak dengan uap, maka dapat menimbulkan iritasi mata kronis dan menyebabkan beberapa iritasi kulit. Jika terlalu lama atau berulang-ulang terkena uap, dapat menyebabkan infeksi pernafasan.
  1. Pertolongan Pertama
  • Kontak Mata
Jika kontak dengan mata , basuh mata dengan air paling tidak selama 15 menit. Gunakan air dingin. Dan segera cari pertolongan medis.
  • Kontak Kulit
Jika kontak, bilas bagian yang terkena asam Nitrat dengan air paling tidak 15 menit sambil melepas pakaian yang terkontaminasi. Cuci pakaian  yang terkontaminasi sebelum dipakai lagi.
  • Kontak serius dengan kulit
Cuci dengan sabun desinfektan dan oles  kulit yang terkontaminasi dengan krim anti-bakteri. Carilah segera pertolongan medis.
  • Penghirupan
Jika terhirup, lepaskan ke udara segar.  Jika terjadi gangguan pernapasan, berikan pernapasan buatan. Jika sulit bernapas, berikan oksigen. Segera cari pertolongan  medis.
  • Penghirupan Serius
Evakuasi korban ke daerah yang aman sesegera mungkin. Jika terfjadi kesulitan bernafas, longgarkan pakaian korban dan berikan oksigen. Jika korban tidak bernafas, berikan nafas buatan. AWAS: “hal ini mungkin berbahaya bagi orang yang memberikan nafas buatan sebab bahan-bahan beracun dan korosif dapat terhirup. Segera cari pertolongan medis.
  • Pencernaan
Jika tertelan jangan dimuntahkan kecuali diarahkan oleh ahli medis. Jagan memberikan sesuatu pada mulut korban yang tidadk sadar. Loggarkan pakaian korban. Segera cari pertolongan medis.
  • Pencernaan Serius
Tidak tersedia
  1. Menghindari Kecelakaan
  • Tumpahan kecil : Encerkan dengan air dan diserap dengan kain, atau serap dengan bahan kering yang inert dan tempatkan dalam wadah pembuangan limbah yang sesuai. Jika perlu, netralkan residu dengan larutan Natrium Karbonat encer.
  • Tumpahan banyak : Cairan korosif. Bahan pengoksidasi. Cairan beracun. Tutup kebocoran jika tidak berbahaya. Serap dengan tanah kering, pasir atau bahan yang tidak mudah terbakarb lainnya. Jangan menaruh air di samping wadah. Hindari kontak dengan bahan yang mudah terbakar (kayu, kertas, minyak, kain, dan lain-lain). Jaga kelembaban dengan menggunakan semprotan air. Jangan tumpahkan material. Netralkan residu dengan larutan Natrium karbonat encer.
  1. Penanganan dan Penyimpanan
  • Yang perlu diwaspadai :
Wadah tetap terkunci, dan kering. Jauhkan dari panas. Jauhkan dari sumber api dan material yang mudah terbakar. Jangan dimakan. Jangan menghirup gas/asap/ uap. Jangan menambahkan air ke bahan ini. Jika ventilasi tidak baik gunakan peralatan pernafasan yang baik. Jika tertelan, segera cari pertolongan medis dan tunjukkan label bahan. Hindari kontak dengan kulit dan mata, jauhkan dari bahan pereduksi, bahan mudah terbakar, bahan organik, logam, asam, alkali, dan panas matahari. Dapat merusak permukaan logam. Simpan dalam drum logam atau drum papan fiber  yang terlapisi menggunakan bagian dalam yang terlapisi polyethylen yang kuat.
  • Penyimpanan :
Jaga wadah dalam keadaan tertutup rapat. Tempatkan wadah di ruang berventilasi dan dingin. Pisahkan dari asam, alkali, agen pereduksi, dan bahan mudah terbakar.
  1. Proteksi Diri
  • Teknis perawatan
Sediakan ventilasi yang kering untuk menjaga kelembaban air dibawah nilai batas. Pastikan keran pencuci mata dan shower keselamatan dapat digunakan dengan baik.
  • Perlindungan Personal
Pelindung wajah. Pelindung tubuh lengkap. Respirator uap. Pastikan memakai respirator yang bersertifikat. Sarung tangan dan sepatu boot dalam keadaan baik.
  • Perlindungan personal saat tumpahan yang banyak
Pakaian praktikum lengkap, respirator uap, boot, sarung tangan. Menggunakan perangkat penutup hidung untuk menghindari terserapnya zat.
  1. Sifat-Sifat Larutan dan Kimia
  • Bentuk fisik dan penampilan : cairan
  • Bau : menyengat
  • Rasa : tak berasa
  • Berat molekul : tidak ada
  • Warna : tak berwarna sampai kuning cerah
  • pH(1% larutan dalam air) : asam
  • Titik didih : 1210 C / 249,80 F
  • Titik leleh : - 41,60 C / -42,9 F
  • Titik Kritis : Tak teridentifikasi
  • Berat jenis : 1,408 (air=1)
  • Tekanan uap : 6 kPa (200 C)
  • Massa jenis uap : 2,5 (air=1)
  • Volatilitas : Tak teridentifikasi
  • Batas Aman uap : 0.29 ppm
  • Koefisien distribusi air/ minyak : Tak teridenfikasi
  • Ionisasi dalam air : Tak teridenfikasi
  • Sifat Dispersi : Larut dalam air, dietil eter,
  • Kelarutan : Mudah larut dalam air dingin,   air hangat, dietil eter.  
  1. Stabilitas dan Reaktivitas
  • Stabilitas : Produk stabil
  • Temperatur yang tidak stabil : Tidak ada
  • Kondisi tidak stabil : Bahan yang tidak cocok
  • Tidak cocok dengan beberapa bahan : Sangat reaktif dengan alkali, bahan pereduksi, bahan yang mudah terbakar, bahan organik, asam, dan logam.
  • Korosivitas : sangat korosif terhadap Aluminium, tembaga. Non-korosif dengan kaca, stainless steel (304/316), kuningan.
  • Keterangan khusus dalam reaktivitas : Pengoksidasi uap. Bereaksi keras dengan alkohol, material organic, turpentin(getah pinus),batubara. Bereaksi keras dengan Aseton  dan Asam sulfat. HNO3 bereaksi dengan air atau uap air untuk memproduksi panas dan racun, korosif, dan uap yang  mudah terbakar.
  • Keterangan khusus dalam korosivitas  : dengan hadirnya bahan pengoksidasi, akan bereaksi dengan semua logam basa kecuali aluminium dan baja kromium. Ini juga bereaksi dengan plastik, karet, dan cat. Tidak merusak perunggu baja, dan seng.
  • Polimerisasi : Tidak terjadi.
  1. Informasi Toksikologi
  • Jalan masuk : langsung terserap dalam kulit. Kontak dengan kulit, mata. Pernafasan dan pencernaan.
  • Efek racun pada hewan : Tidak ada
  • Efek Kronis pada manusia : mengandung material yang menyebabkan kerusakan pada organ seperti paru paru, membran mukosa, sistem pernafasan bagian atas, mata, dan gigi.
  • Efek lain pada manusia : sangat berbahaya pada pernafasan (merusak paru paru), pada kontak kulit, mata , dan pencernaan.
  • Keterangan khusus efek Kronis pada hewan : LDL
  • Keterangan khusus efek Kronis pada manusia : Mengganggu reproduksi, gangguan pada kelahiran dan janin (berdasar data pada hewan).

  1. Informasi Ekologi
  • Pencemaran lingkungan : tidak ada
  • BOD dan COD : tidak ada
  • Pengrusakan lingkungan : mungkin bahaya singkat dari peruraian tidak terlihat, tetapi peruraian dalam jangkan panjang dapat terlihat.
  • Efek racun pada peruraian produk : peruraian produk tidak lebih beracun daripada produk itu sendiri
  • Keterangan lain : tidak ada

Global Energy Transfer, Atmosphere and Ocean Circulation, Climate

The Earth is an interacting system of matter and energy, that as part of its functioning produces phenomena like volcanoes, glaciers, mountain ranges, oceans, and continents.  The energy that keeps this system going is on one hand the internal heat (from radioactive decay) that drives plate tectonics, and on the other hand solar energy that maintains ocean and atmosphere circulation and helps to drive erosion.
In the previous chapter we have discussed the internal processes (radiogenic heat production, mantle convection) that drive plate tectonics and crustal dynamics.   Geologists call this complex of internal processes the Tectonic System.   They refer to the complex of solar powered external processes (atmosphere and ocean circulation, erosion) as the Hydrologic System, because water and its properties are the key ingredient.
THE HYDROLOGIC SYSTEM  includes the entire cycle (hydrologic cycle) of water movement on the Earth (be it on the surface or in the air). The driving force behind this cycle is the energy input from the sun.



 THE HYDROLOGIC CYCLE as shown in above diagram shows the various pathways of (1) water to the oceans (rivers, glaciers, precipitation); (2) water into the atmosphere by evaporation (from falling rain, rivers & lakes, soil, the oceans, transpiration by plants); and (3) onto the landmasses (by rain, snow).  Water movement/transport occurs through movement of clouds, by rivers, ocean circulation, groundwater flow, and evaporation.
The bulk of the water is contained in the oceans, which contain about 30000 times more water than atmosphere and continents combined, cover approximately 70% of the Earth's surface and are on average 3800 m deep.  The remainder of the water is found in ice caps & glaciers (3%), groundwater (1%), and rivers and lakes (0.01%).  The latter two reservoirs constitute the terrestrial fresh water supply. Thus, only a very   small fraction of the overall water supply is suitable and available for human use. The water transfer between these reservoirs is accomplished by the processes of evaporation, transpiration, precipitation, and flow of water (following gravity).
Two minor reservoirs by size, the atmosphere (0.001%) and the biosphere (the totality of living tissue; 0.0001%) play a role that is not reflected by their size. As we shall see below, cycling of water through the atmosphere is an important factor for energy transfer in the atmosphere, and in Chapters 7 through 11 we will look at the important role that organisms play in driving the evolution of the climate and atmosphere evolution through the production and consumption of the greenhouse gases carbon dioxide and methane.
Every year about 30000 to 40000 cubic kilometers (a cube 30-35 km in size) of water move across the surface of the continents to the oceans, profoundly shaping the surface of the continents. Evaporation by the sun effects lifting of water into the atmosphere, and the counterforce to this process is gravity that forces rain to fall back on the earth and causes water move back to the oceans in streams (river systems), on the way eroding soils, cutting canyons, and transporting solids (silt, sand, clay) and dissolved salts to the oceans. The transfer of water vapor from the oceans to the atmosphere goes hand in hand with the transfer of tremendous amounts of thermal energy to the atmosphere and is very important for atmospheric circulation (see below). For this reason atmospheric circulation and winds can be considered part of the hydrologic cycle.
In cold climates water in the form of glaciers (glacial systems) moves downslope due to gravity, erodes bedrock by abrasive action, and transports sediment. Glaciers may either enter the sea directly, or melt at the end and add their water to the continental surface runoff.
Water may also seep into the porous portions of the earth's surface and is then called groundwater (groundwater systems). It may dissolve rocks in the subsurface and create karst systems (caves in limestone) and sinkholes.
Along the shores of oceans (shoreline systems) water that is agitated by waves (wind, atmospheric circulation) erodes and moves sediment and forms beaches, sandbars, lagoons, and related coastal features.
Winds (eolian system) can carry considerable amounts of sand and dust and can profoundly shape landscapes (sand seas of deserts) as well as human destiny (the highly fertile loess plains of southern China, without them it would be much more difficult to feed a population of 1 billion people).
Thus, the hydrologic cycle affects a broad range of landscape-shaping dynamic systems.  We therefore consider river systems, glacial systems, groundwater systems, shoreline systems, and eolian systems as subsystems of the hydrologic system.  In terms of overall importance for the shaping of the Earth surface, river systems are the primary force.  Glaciers, although very powerful in modifying the land surface, were only abundant for brief intervals in Earth history.

Rain on the Cumberlands
Through the stricken air
Through the buttonwood balls suspended on twig strings
The rain-fog circles and swallows
Climbs the shallow plates of bark, the grooved trunks
And wind pellets go hurrying though the leaves
Down, down the rain
Down in plunging streaks of watered gray.
Rain in the beechwood trees
Rain upon the wanderer whose breath lies cold upon the mountainside
Caught up with broken horns within the nettled grass
With hooves relinquished on the breathing stones eatened with rain strokes
Rain has buried her seed and her dead
They spring together in this fertile air loud with thunder
 

Both, the tectonic and the hydrologic system, are characterized by ongoing transfers of energy and matter.
The forms of energy that are most important in geologic processes are:
  • Kinetic Energy (meteorite impact, movement of wind and water, ocean currents)
  • Gravitational Potential Energy (falling rain gains kinetic energy from its gravitational potential, water flowing down from mountains)
  • Thermal Energy (input from the sun, radioactive decay, molten rocks).  Transmitted by conduction, convection, radiation
  • Chemical Energy (holds together atoms in molecules, the energy of the chemical bond)
  • Nuclear Energy (released during radioactive decay)
All those various forms of energy occur and are transformed into each other as geologic processes proceed (kinetic energy to heat during meteorite impact; thermal energy to chemical energy and vice versa during melting and recrystallization; thermal energy into gravitational potential energy [sun evaporates water and forms clouds] - gravitational potential energy into kinetic energy [rain drops fall])

 The total amount of energy that moves through the system is huge. It is on the order of 174 ,000 terawatts (1 terawatt = 1012 watts [energy per time]; 1 horsepower = 746 watts).  Almost all of this energy comes to us via solar radiation.  The Earth system receives 5000 times more energy from the sun than from the interior of the planet.  Thus, although its manifestations are impressive (mountain ranges, earthquakes, volcanoes), the internal energy that keeps up mantle convection and drives the tectonic plates is only a small fraction of the energy that moves through the system.   To put it into perspective, the total energy production by humans is about 9.6 terawatts at any given time.  Thus, there is plenty of energy in the system.   Even if humans were to extract all their energy needs from the solar input, there would still be plenty of energy left to keep the planet going.


Solar energy input dominates the surface processes (wind, weather, climate, ocean circulation, etc.) of the Earth, and because the Earth is a sphere, its input is not uniform across the planet.  The concentration of solar energy per unit area depends on the angle at which the solar radiation arrives.  In equatorial regions, where the sun's rays come in more or less perpendicular, a maximum amount of heat is received.   In polar regions, on the other hand, the sun's rays come in slanted at a shallow angle and considerably less heat is received (see diagram below).
  Average Earth surface temperatures.  Blue indicates lowest temperatures (polar regions), red indicates highest temperatures (around the equator).  The data used for this diagram were collected between January 1985 and December 1992.




As a consequence, the polar regions stay cooler.  Just like in our hot water pot that was heated from below, the uneven global heat distribution gives rise to convection currents that attempt to equalize the heat distribution.
In its most simple form we can imagine that heated air at the equator rises up, and spreads north and south towards the poles.  It gradually cools, sinks down in the polar regions, and then flows across the Earth surface to the equator.  There it heats up again and the convective cycle is repeated.  This is what would happen if the Earth did not rotate.  Rotation adds another twist to the story, because the Coriolis Effect makes the northward flowing currents veer off course (to the right, in the direction of rotation).   The Coriolis Effect breaks the air exchange between equator and poles into three circulation belts.  We have seen this effect also in the atmospheres of large gas planets in Chapter 2.

  
 An idealized view of global air circulation.
Along the equator, surface winds converge,
bringing with them abundant moisture.
Thus, clouds are abundant in this area and it
rains a lot.  Between 20 and 35 degrees
latitude, descending dry and warm air
masses give rise to cloudless skies and
desert climates. Along the polar front, rising
air masses again give rise to cloud formation
and rain.






An important aspect of global air circulation is the movement of water through the atmosphere Water has a much higher heat capacity than the atmospheric gases.  Its heat capacity is approximately four times that of air (heat capacity of water = 1 cal/gm/deg).  In addition, because water changes from the liquid to the gas state (evaporation of water) and back (condensation into clouds) as it gets cycled through the atmosphere, we also have to consider the latent heat of vaporization (540 cal/gm).    This is the amount of heat necessary to get the water molecules into the gas state.  For example, if we evaporate a liter (1 kg) of water, 540,000 calories of latent heat are stored in the vapor.  Once the water condenses, this latent heat is released, and heats up the surrounding air.  If we assume for example that this water vapor is contained in 1000 kg of air (roughly 1000 cubic meters, or a cube of 10 meters size), it would heat up this air mass by about two degrees as it condenses.  Air at 30 degrees C (86 degrees F) can hold up to 30 grams of water vapor per cubic meter (or kilogram) of air.  If this water vapor  condenses it releases 16,200 calories of latent heat.  This in turn can cause the air to heat up as much as 64 degrees C.   It is just like heating the air up in a hot air balloon.  The air will expand and rise (think of rising and billowing clouds before a thunderstorm).  For these reasons, condensing or vaporizing water has a profound effect on atmospheric circulation, and moist air masses are prone to very powerful climatic disturbances (e.g. thunderstorms, tornadoes, hurricanes).
Water vapor is constantly cycling through the atmosphere, evaporating from the surface, condensing to form clouds blown by the winds, and subsequently returning to the Earth as precipitation. Heat from the Sun is used to evaporate water, and this heat is put into the air when the water condenses into clouds and precipitates. This evaporation-condensation cycle is an important mechanism for transferring heat energy from the Earth's surface to its atmosphere and in moving heat around the Earth.  

 













This image shows global humidity patterns (April 27, 1995, at 1745 UTC, measured by the GOES 8 satellite).  The areas with the lowest humidity (brownish) are those that have the weakest circulation and were feared by sailors because of a lack of sustained winds.
Water also has a substantially higher heat capacity than rocks (by a factor of five), and therefore the oceans can store much more heat than the land surfaces of the planet.   Because the oceans also cover about 70% of the Earth surface and are on average 3.8 km deep, they are the major heatsink of the planet and serve as temperature buffers for the ocean/atmosphere system.  The bulk of the thermal energy at the Earth surface is stored in the oceans. The large thermal inertia of the oceans is a key factor in stabilizing Earth's climate.
Because the oceans are of course also heated more intensely in the equatorial regions, there is abundant warm water near the equator, and cold water in the polar regions.   The atmospheric circulation that is set up between the equator and the poles also influences the redistribution of these water masses.  Wind blowing over the ocean surface exerts drag (friction) and starts to move the surface waters.  In addition the currents are influenced by the Coriolis Force and the tides. A general pattern of ocean current is shown in the map below.










The currents are also influenced by the position of landmasses.  Whereas in the Pacific we have currents that more or less correspond to the patterns of the surface winds, current patterns look more complex in the Indian Ocean and the Atlantic.  In the North Atlantic, the Gulfstream moves warm equatorial surface waters northward, and a return current of cold arctic water moves southward across the Atlantic seafloor.
Decades of research on ocean currents have revealed that there is a large scale oceanic circulation system.  The Gulfstream that moves into the North Atlantic finally sinks as it cools and returns south across the Atlantic seafloor, flows as a bottom current into the South Atlantic, and then rises to the surface again in the Indian Ocean and the Eastern Pacific, only to warm up (absorbing heat from overlying air masses) and turn west to feed back into the Gulfstream.  Actually, the sinking of the Gulf Stream is not so much a consequence of cooling and density increase, but one of salinity.  Equatorial surface waters are more saline (high evaporation), and the waters of the North Atlantic are less saline (because they mix with meltwater [low salinity] from icebergs and from the Greenland ice cap). Thus, once the Gulfstream cools sufficiently it is heavier that the lower salinity North Atlantic seawater and sinks.  A complete run through this current system is estimated to take about 1000 years.










At the moment this current system appears very stable, but comparatively minor changes may upset the delicate balance of temperature differences and prevailing winds.  For example, scientists have speculated that melting of the Greenland icecap could introduce so much meltwater (of low salinity and low density) to the North Atlantic that the Gulfstream is prevented from sinking and returning as a southward flowing bottom current.   This would interrupt the current system and cause equatorial waters (and regions) to get warmer, and northern Europe to get colder.  Spock says....
Atmospheric and oceanic circulation are closely coupled.  For example, changes in the pattern of sea surface temperatures are reflected in changes of wind patterns around the globe (water masses transfer or absorb heat to/from overlying air).    Specific examples for this kind of interaction are weather phenomena knows as El Nino and La Nina (these will be discussed later).

On the modern Earth, the Tectonic System, the Hydrologic System (atmosphere & hydrosphere), and organic life (biosphere) interact in complex ways, and matter and energy is exchanged between these subsystems.  The net result of all these interactions, when averaged over periods of decades to centuries, is the Earth System's overall "condition", a state of dynamic equilibrium.  The global climate is a major expression of this "condition".

CLIMATE

At its simplest, climate is a reflection of  local, regional, and global distributions of temperature and precipitation -- in turn determined by the latitudinal distribution of the energy received from the Sun, the absorption and transport of that energy within the Earth System, and its re-emission to space.

Although circulation of air masses and ocean waters (as outlined above) plays a significant role in determining global heat exchange and average world temperatures, there are several other, more fundamental, controls on climate.  The basic items that determine Earth climate are:
  1. Astronomical Parameters
  2. Distribution of Continents and Oceans
  3. The Greenhouse Effect
Item 2 (Distribution of Continents and Oceans) is most important because it determines the routing of global current systems and therefore the intensity/strength of the oceanic heat exchange between equatorial and polar regions.   The movement of the continents across Earth's surface modulates the global climate on very long time scales by changing wind patterns, ocean currents, and the ease with which ice can accumulate. Under some configurations of continents and oceans the heat exchange may be severely impeded, leading to hot tropics and ice covered polar regions.  Also, when we have all the landmasses bunched up in the polar regions the warm ocean current may not get far enough north and we end up with glaciated continents.  Conversely, when we have all the continents hanging around the equator, the polar regions have very good oceanic heat exchange and world temperatures would be more uniform.
Item 3 (Greenhouse Effect) will be discussed at some length later in this lecture.   Basically, this is where linkage to the biosphere comes in.
Item 1 (Astronomical Parameters), will be surveyed now, because we have already set the stage by going over the origin of the solar system.  

Earth's rapid rotation about its axis (compared to the time for one orbit around the Sun) determines day and night, spreads the incoming solar radiation more or less uniformly around circles of latitude, and strongly affects circulation patterns in the oceans and atmosphere.
The eccentricity of Earth's orbit modulates the intensity of the incoming solar radiation through the course of the year. 
The tilt of Earth's axis with respect to the ecliptic plane results in the seasons.  Note, that it is summer in the northern hemisphere when the Earth is closest to the sun (perihelion, January 3rd, 147 million km), and winter when it is farthest away (aphelion, July 4th, 152 million km).  Thus, the tilting of the northern hemisphere towards the sun in summer (longer days, more solar energy input) and the tilting away from the sun in the winter (shorter days, less solar energy input) are more important than the actual distance to the sun.

The relationship between the eccentricity of Earth's orbit and the orientation (tilt) of the planet's axis of rotation vary systematically over time.  This causes cyclic shifts of solar energy input that can produce climate modulations (repetitive temperature variations).  These variations are termed Milankovitch cycles in honor of  Serbian astrophysicist and mathematician Milutin Milankovitch  who in 1920  figured out these variations and proposed that they influence world climate.








This image shows a tracing of ocean surface temperatures for the past 700,000 years, based on oxygen isotopes of marine microfossils. We see a very clear periodicity of ca. 100,000 years (the eccentricity cycle of Milankovitch), and a superimposed periodicity of ca. 20,000 years (the precession cycle of Milankovitch).
Fluctuations in the Sun's output (apparently with a period of 500 to 1000 years) may produce small changes in climate over intervals of 100 to 200 years.  A time interval of cooler temperatures that ranged from the mid-14th to the mid-19th century, also known as the "Little Ice Age", may have been caused this way, but this is a tentative interpretation. The Little Ice Age brought an end to an unusually warm era known as the Medieval climate optimum, and brought bitterly cold winters to many parts of the world. It is most thoroughly documented in Europe and North America. In the mid-17th century, glaciers in the Swiss Alps advanced, gradually engulfing farms and crushing entire villages. The River Thames and the canals and rivers of the Netherlands often froze over during the winter, and people skated and even held fairs on the ice. In the winter of 1780, New York Harbor froze, allowing people to walk from Manhattan to Staten Island. Sea ice surrounding Iceland extended for miles in every direction, closing that island nation's harbors to shipping. The severe winters affected human life in ways large and small. Famines became more frequent (the one in 1315 killing 1.5 million people alone), and deaths from disease increased. The population of Iceland fell by half, and the Viking colonies in Greenland died out. The Little Ice Age can be seen in the art of the time; for example, snow dominates many village-scapes by the Flemish painter Pieter Brueghel the Younger, who lived from 1564 to 1638.


Eventually, all things merge into one, and a river runs through it.
The river was cut by the world's great flood and runs over rocks from the basement of time.
On some of the rocks are timeless raindrops.
Under the rocks are the words, and some of the words are theirs.
I am haunted by waters.
From: A River Runs Through It  by Norman Maclean

http://www.indiana.edu/~geol105/1425chap4.htm