the ocean depth.pdf

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THE OCEAN DEPTH

Farid K. Muzaki, S.Si., M.Si

Jurusan BIOLOGI

FMIPA – ITS Surabaya

Marine Biology – SB091540



Zonasi habitat perairan

laut terbuka; tampak

korelasi dengankelimpahan plankton dan

ketersediaan cahaya



Environmental variables

Cahaya no light (except for mesopelagic zones) no

photosynthetic activities food is scarce

Salinitas cenderung tidak berbeda dengan di epipelagik

Suhu

turun drastis (fluktuasi tinggi) di zona mesopelagiknamun cenderung lebih stabil pada zona di bawahnya

(bathypelagic, abyssopelagic, hadopelagic)

Oksigen rendah pada lapisan pycnocline lebih tinggi pada

laut dalam Food scarce



GASES in Seawater

The solubility and saturation value for gases in sea

water increase as temperature and salinity decrease

and as pressure increases

Solubility is the ability of something to be dissolved and go into solution Saturation value is the equilibrium amount of gas dissolved in water at an

existing temperature, salinity and pressure

The surface layer is usually saturated in atmospheric gasesbecause of direct exchange with the atmosphere



Gases in seawater: O2



Oxygen tends to be abundant in the surface layer and deep layer

bottom, but lowest in the pycnocline

Surface layer is rich in oxygen because of photosynthesis and contact with the

atmosphere

Oxygen minimum layer occurs at about 150 to 1500m below the surface and

coincides with the pycnocline

Sinking food particles settle into this layer and become suspended in place

because of the greater density of the water below The food draws large numbers of organisms which respire, consuming oxygen

Decay of uneaten material consumes additional oxygen

Density difference prevents mixing downward of oxygen-rich water from the

surface or upwards from the deep layer




The deep layer is rich in oxygen because its water

is derived from the cold surface waters which sank

(convect) to the bottom. Consumption is low because

there are fewer organisms and less decayconsuming oxygen

Anoxic waters contain no oxygen and are inhabitedby anaerobic organisms (bacteria)




Food



Adaptasi di zona mesopelagik: FOOD

Makanan jarang (sebagian besar berasal dari lapisan laut di

atasnya (epipelagik) kelimpahan & keanekaragaman

rendah

Sebagian besar berupa karnivor

Makanan jarang ukuran tubuh kecil namun mulut besar dan

memiliki semacam “engsel” (hinge) memudahkan memangsa

makanan yg jauh lebih besar gigi besar, melengkung ke

dalam memastikan mangsa tidak terlepas lagi



Cahaya minim mata besar dan sensitif tubular eyes

optimalisasi visual sense arah depan dan atas

Adaptasi di zona mesopelagik: mata

Retina di pangkal silinder untuk melihat objek yang dekat, di dinding

silinder untuk melihat objek yang jauh



Migrasi vertikal naik ke epipelagik saat malam untuk

makan, turun ke mesopelagik saat siang untuk istirahat dan

menghindari predator.

Misalnya pada zooplankton dan beberapa jenis ikan

Adaptasi di zona mesopelagik: migrasi



Migratory vs non-migratory fishes



Ikan mesopelagik cenderung berwarna abu-abu keperakan atau hitam

kelam; sebaliknya invertebrata mesopelagik cenderung berwarna ungu

atau merah cerah

Adaptasi: counter-shading, transparency, reduction of silhouette

Adaptasi di zona mesopelagik: warna



Counter-silhouette bioluminescence


sebenarnya, mekanisme BIOLUMINESENS umum terjadi di laut, tetapi

di laut dalam kondisi ini mengalami perkembangan tertinggi dan

paling kompleks

Bioluminesens = produksi cahaya oleh makhluk hidup ~ spektrum

warna yg dihasilkan berbeda menurut spesies, tp secara menyeluruh

meliputi warna-warna yg dpt dilihat oleh mata, dari ungu hingga

merah.

Organ penghasil cahaya disebut FOTOFOR ~ hewan dg fotofor

terbanyak berada di zona mesopelagik dan bagian atas zona

batipelagik ~ dilaut-dalam terbatas.



Dari sudut adaptasi, produksi cahaya sangat penting bagi organisme ygbersangkutan, diantaranya :1. sering dijumpainya organisme penghasil cahaya di laut-dalam, dan2. dibentuknya organ-organ yg anatominya sangat kompleks utkmenghasikan cahaya

fotofor jg dpt digunakan utk menghasilkan ‘cahaya kilat’ yg menyilaukanshg melumpuhkan predator sejenak

fotofor jg berfungsi utk menerangi daerah sekitarnya, shg predator dptmelihat mangsanya.

fotofor jg berfungsi sbg umpan agar mangsa mendekat hingga mencapaibatas terkaman.

fotofor jg diduga utk mekanism pengenalan thd kerabat spesiesnya.




Adaptasi di laut dalam

Secara prinsip, adaptasi nekton di zona bathypelagic,

abyssopelagik atau hadopelagic relatif serupa dengan di

zona mesopelagik

Khusus untuk makanan yang terbatas, nekton lebih bersifat

karnivor, scavenger atau bacterial feeder

Karena mangsa sangat langka, maka banyak spesies

menggunakan bioluminescence untuk menarik mangsa; selain

itu, terdapat beberapa spesies dengan adaptasi ekstrem

menjadi “pemancing”

Terkait dengan tidak adanya cahaya, ikan laut dalam

umumnya bermata kecil atau tampak tidak memiliki mata



Sex in the deep

Populasi rendah

susah cari pasangan

Adaptasi

hermaphrodites,

secretion of

pheromones,

bioluminescence and

male parasitism



Adaptasi nekton



Anomalies: GIGANTISM

Invertebrata laut dalam cenderung lebih besar

daripada di zona epipelagic



Teori penjelasan gigantisme:

Tekanan hidrostatik yang tinggi mengakibatkan kelainan pada

metabolisme hewan

Kombinasi antara suhu rendah dan langkanya pakan akan

mengurangi laju pertumbuhan pada krustasea

Ada juga dugaan gigantisme disebabkan aksi seleksi alamiah

– lebih struggle mengatasi faktor pembatas laut dalam

Anomalies: GIGANTISM



Benthic of the deep sea

Feeding habit scavenger atau deposit feeder

Taksa Asteroidea, Holothuroidea, Crustacea,

Polychaeta, Crinoidea, Echinoidea



Hydrothermal vents

Review: mid-oceanic ridge

Hydrothermal vent communities vary

considerably from place to place.

No sunlight, primary productivity bychemosynthetic archaea and

bacteria.

Some of these microbes are

extremophiles (can live at

temperature over 110⁰C).



The hot water from chimney or black smokers contain a rich sulfide

minerals, as well as hydrogen sulfide (H2S) which is toxic for

most organisms but is an energy-rich molecule.

No sunlight, primary productivity by chemosynthetic archaea and

bacteria. Chemosynthetic microbes that use the energy in hydrogen sulfide

and sulfide minerals to make inorganic matter are the base of the

food chain.

Some of these microbes are extremophiles (can live at temperatureover 110⁰C).

Most of animals around chimney or black smokers feed on those

microbes (via filter feeding mechanism)

Hydrothermal vents



Some of animals inhabiting the hot spring around

black smoker

Clocwise from

top left:

Bathymodiolus

Calyptogena

Rimicaris

Riftia



Riftia pachyptila;

A tube worm

commonly found on

Eastern Pacific vent

communities.

They’re not filter

feeder, so how they

got their energy?

Special cases of endosymbiont in deep sea hot

spring vent: Riftia pachyptila



Special cases of endosymbiont in deep sea hot

spring vent: Riftia pachyptila

Riftia does not a filter feeder. In fact, it doesn’t even have a

mouth nor digestive tract. So, how they feed?

These worms have a highly specialized organ called atrophosome ("feeding body") that is packed with symbiotic

bacteria. The bacteria perform chemosynthesis inside the worm's body

and pass much of the organic matter they produce on to theworm. The worm, in turn, supplies the bacteria with rawmaterials. The bright-red plume acts like a gill, exchanging not

only carbon dioxide and oxygen, but also hydrogen sulfide.

The tube worm's blood has special hemoglobin that chemicallybinds the hydrogen sulfide, protecting the worm from itspoisonous effects.



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