Berliner Boersenzeitung - Life in the abyss, a spectacular and fragile struggle for survival

EUR -
AED 4.322512
AFN 81.008431
ALL 97.610159
AMD 449.741076
ANG 2.106185
AOA 1079.159835
ARS 1481.251332
AUD 1.778449
AWG 2.12125
AZN 2.003676
BAM 1.956004
BBD 2.367977
BDT 142.954879
BGN 1.954562
BHD 0.44362
BIF 3495.323193
BMD 1.176837
BND 1.498369
BOB 8.103878
BRL 6.492024
BSD 1.172722
BTN 101.327116
BWP 15.651629
BYN 3.838111
BYR 23066.014699
BZD 2.355775
CAD 1.600893
CDF 3396.35309
CHF 0.932803
CLF 0.028445
CLP 1115.888998
CNY 8.426868
CNH 8.413905
COP 4754.423438
CRC 592.461663
CUC 1.176837
CUP 31.186193
CVE 110.275072
CZK 24.585343
DJF 208.621713
DKK 7.463645
DOP 70.987388
DZD 152.555099
EGP 57.771804
ERN 17.652562
ETB 160.238378
FJD 2.628111
FKP 0.870508
GBP 0.867253
GEL 3.189247
GGP 0.870508
GHS 12.255119
GIP 0.870508
GMD 84.732712
GNF 10175.059015
GTQ 9.000899
GYD 245.223439
HKD 9.237621
HNL 30.708196
HRK 7.532461
HTG 153.884709
HUF 398.525381
IDR 19160.091087
ILS 3.920552
IMP 0.870508
INR 101.5862
IQD 1536.259893
IRR 49559.564856
ISK 142.209258
JEP 0.870508
JMD 188.119579
JOD 0.834323
JPY 171.969496
KES 151.462488
KGS 102.823942
KHR 4700.449279
KMF 494.85638
KPW 1059.21497
KRW 1609.28981
KWD 0.358947
KYD 0.977293
KZT 631.140326
LAK 25280.631195
LBP 105081.740809
LKR 353.806824
LRD 235.133474
LSL 20.593843
LTL 3.474895
LVL 0.711857
LYD 6.34166
MAD 10.546843
MDL 19.831064
MGA 5180.539188
MKD 61.566669
MMK 2470.300458
MNT 4220.581008
MOP 9.481487
MRU 46.545844
MUR 53.240152
MVR 18.118785
MWK 2033.511647
MXN 21.828101
MYR 4.963309
MZN 75.27023
NAD 20.593668
NGN 1794.147061
NIO 43.154491
NOK 11.895829
NPR 162.123874
NZD 1.944394
OMR 0.452496
PAB 1.172727
PEN 4.180135
PGK 4.929513
PHP 66.643719
PKR 333.873949
PLN 4.25242
PYG 8784.399462
QAR 4.27529
RON 5.072876
RSD 117.135316
RUB 92.264883
RWF 1695.176433
SAR 4.414972
SBD 9.750211
SCR 17.021093
SDG 706.681753
SEK 11.192713
SGD 1.501368
SHP 0.924809
SLE 27.008153
SLL 24677.698279
SOS 670.169751
SRD 42.892196
STD 24358.159906
STN 24.50255
SVC 10.261068
SYP 15301.194295
SZL 20.584142
THB 37.932992
TJS 11.252223
TMT 4.1307
TND 3.423613
TOP 2.756275
TRY 47.636612
TTD 7.958761
TWD 34.451933
TZS 3065.661464
UAH 49.037504
UGX 4210.402439
USD 1.176837
UYU 47.144706
UZS 14898.550633
VES 141.542248
VND 30766.650779
VUV 141.29205
WST 3.102248
XAF 656.025279
XAG 0.030177
XAU 0.000349
XCD 3.180462
XCG 2.11352
XDR 0.815885
XOF 656.025279
XPF 119.331742
YER 283.55937
ZAR 20.653556
ZMK 10592.964164
ZMW 27.238339
ZWL 378.94119
  • SCU

    0.0000

    12.72

    0%

  • RYCEF

    0.2000

    13.5

    +1.48%

  • RBGPF

    0.9700

    68

    +1.43%

  • RIO

    0.2900

    64.62

    +0.45%

  • CMSC

    -0.0400

    22.43

    -0.18%

  • GSK

    1.0100

    38.03

    +2.66%

  • SCS

    0.2100

    10.68

    +1.97%

  • CMSD

    -0.0300

    22.89

    -0.13%

  • RELX

    0.4100

    53.09

    +0.77%

  • NGG

    -1.6300

    72.65

    -2.24%

  • BTI

    0.1500

    52.37

    +0.29%

  • BCC

    1.2000

    88.35

    +1.36%

  • VOD

    -0.0200

    11.3

    -0.18%

  • JRI

    0.0000

    13.21

    0%

  • AZN

    2.5200

    73

    +3.45%

  • BCE

    0.2200

    24.6

    +0.89%

  • BP

    0.1900

    32.71

    +0.58%

Life in the abyss, a spectacular and fragile struggle for survival
Life in the abyss, a spectacular and fragile struggle for survival / Photo: RUSS HAPCROFT - UNIVERSITY OF ALASKA/AFP/File

Life in the abyss, a spectacular and fragile struggle for survival

Cloaked in darkness and mystery, the creatures of the deep oceans exist in a world of unlikely profusion, surviving on scant food and under pressure that would crush human lungs.

Text size:

This extremely hostile environment, which will come under the spotlight at a major United Nations oceans summit in Lisbon this week, has caused its inhabitants to develop a prodigious array of alien characteristics and idiosyncratic survival techniques.

A vast assortment of animals populate the sunless depths, from the colossal squid, which wrapped its tentacles around the imaginations of sailors and storytellers, to beings with huge cloudy eyes, or whose bodies are as transparent as glass.

And the angler fish, with its devilish looks illuminated by a built-in headlamp, showing that the deep dark is alive with lights.

- 'Incredible' creatures -

Until the middle of the 19th century, scientists believed that life was impossible beyond a few hundred metres.

"They imagined that there was nothing, because of the absence of light, the pressure, the cold, and the lack of food," Nadine Le Bris, a professor at Sorbonne University, told AFP.

Between 200 and 1,000 metres (650 to 3,300 feet), the light fades until it vanishes completely, and with it plants; at 2,000 metres the pressure is 200 times that of the atmosphere.

From the abyssal plains to the cavernous trenches plunging deeper than Everest is high, aquatic existence continues in spectacular diversity.

"When people think of the deep sea they often think of the seafloor," said Karen Osborn of the Smithsonian's Natural History Museum.

"But all that water in between is full of incredible animals. There is a ton of life."

These open water inhabitants face a formidable challenge: they have nowhere to hide.

"There's no seaweed to hide in, no caves or mud to dig into," said Osborn.

"There are predators coming at them from below, from above, from all around."

- Masters of disguise -

One tactic is to become invisible.

Some creatures are red, making them difficult to distinguish in an environment where red light no longer filters through.

Others render themselves transparent.

Take the transparent gossamer worm, which ranges in size from a few millimetres to around a metre long and shimmies through the water by fluttering its frilly limbs.

"They look like a fern frond," said Osborn.

"They're beautiful animals and they shoot yellow bioluminescent light out of the tips of their arms. What could be better than that."

Bioluminescence is particularly common among fish, squid, and types of jellyfish, according to the US National Oceanic and Atmospheric Administration, which says around 80 percent of animals living between 200 and 1,000 metres produce their own light.

This chemical process might be helpful for defence, reproduction or to find food -- but no one knows for sure why so many creatures have evolved it, says NOAA.

- "Sea snow" -

With no plants around and animals scattered in the vastness doing their utmost to disappear, creatures in the ocean depths often have a hard time finding a live meal.

"If you happen to get lucky and hit a patch of your food, bingo! But you may not see another one for three weeks," said Osborn.

Another option is to feast on the dead.

Organic particles from the surface waters -- disintegrated bodies of animals and plants, mingling with fecal matter -- drift down in what is known as "marine snow".

This cadaverous confetti forms part of a process that sequesters carbon dioxide in the ocean depths.

It is also a lifeline for many deep sea animals, including the blood red vampire squid which, contrary to its reputation, peacefully hoovers up marine snow.

When giants like dead whales sink to the seabed, they are swiftly reduced to bone by scavengers.

- Final frontier -

With most of the oceans still unexplored, it is often said that we know more about the surface of Mars than we do about the seafloor on our own planet.

But unlike outer space, scientists keep finding life even under the most hostile of conditions.

Like the searing hydrothermal vents at the cracks between oceanic plates that spew chemical compounds such as hydrogen sulphide.

Microorganisms use this to create organic matter via "chemosynthesis", like plants use the sun for photosynthesis, which in turn feeds "exuberant" ecosystems, said Pierre-Marie Sarradin, head of the Deep Ecosystems department at the French research agency Ifremer.

These hydrothermal springs were totally unknown until the 1970s.

Scientists have so far identified some 250,000 marine species, though there could still be at least a million to be discovered.

Could there be an elusive sea monster lurking in the depths? Despite measuring more than 10 metres in length the colossal squid has only very rarely been seen.

"I don't think we're going to find a megalodon," said Osborn, referring to the giant ancestor of the shark.

Humans may not have explored much of the deep seas, but they have left their mark, via global heating, overfishing and pollution.

Oceans are acidifying as they absorb more and more CO2, there is a growing prevalence of "dead zones" without oxygen, while microplastics have been found in crustaceans at a depth of nearly 11 kilometres in the Mariana Trench.

Food reaches the bottom in smaller quantities.

Nadine Le Bris said species that "already live at the limits in terms of oxygen or temperature", are already "disturbed".

(Y.Yildiz--BBZ)