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Ecology

Habitat

Depth range based on 19 specimens in 1 taxon.
Water temperature and chemistry ranges based on 18 samples.

Environmental ranges
  Depth range (m): 0 - 0
  Temperature range (°C): 6.814 - 8.734
  Nitrate (umol/L): 12.249 - 18.655
  Salinity (PPS): 34.080 - 34.286
  Oxygen (ml/l): 6.657 - 6.863
  Phosphate (umol/l): 1.016 - 1.359
  Silicate (umol/l): 5.089 - 6.097

Graphical representation

Temperature range (°C): 6.814 - 8.734

Nitrate (umol/L): 12.249 - 18.655

Salinity (PPS): 34.080 - 34.286

Oxygen (ml/l): 6.657 - 6.863

Phosphate (umol/l): 1.016 - 1.359

Silicate (umol/l): 5.089 - 6.097
 
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Evolution and Systematics

Functional Adaptations

Functional adaptation

Pulled support stalks have low flow stress: algae
 

The support stalk (stipe) of seaweed encounters lower flow stresses because it is pulled rather than bent.

       
  "Consider the example of two species of intertidal seaweeds…Lessonia nigrescens and Durvillea antarctica…both species encounter the same range of flow forces, but they differ in their response. L. nigrescens stipes…are bent…D. antarctica…are pulled by moving water. Calculations indicate that stresses in a bent L. nigrescens stipe are roughly 800 times greater than in a pulled D. antarctica stipe of the same dimensions and bearing the same load. These seaweeds illustrate a general principle about organisms bearing loads: stresses are lower if an organism bears a given load in tension than in bending." (Koehl 1984:64)

"In nature, tensile systems are reasonably common and certainly diverse in biological affinities. Among lower plants, the stipes of some large algae are notable. In the Pacific Northwest some algae whose holdfasts are attached to rocks and whose fronds are on the surface have stipes between them well over 100 feet long, stipes that are loaded in tension by waves and tidal currents. Among the higher terrestrial plants we see tensile systems in various epiphytes, tendrils, and dangling fruits. Mussels attach to rocks entirely through the use of tough byssus threads, mainly made of collagen. Even the setae by which the gecko hangs beneath a rock or ceiling are proper tensile systems…Tensile systems ought to scale in an unusual way, something first pointed out by Galileo. Strength doesn't depend on length, so the thickness of your fishing line doesn't have to be adjusted for the depth at which you hang the bait. Cross-sectional area, though, ought to be proportional to load, so diameter ought to scale with the square root of load--load to the 0.5 power. Peterson et al. (1982) looked at several structures normally loaded in tension--fruit stems, algal stipes, and toe-pad setae. They found that in practice, diameter scales with load to the power 0.3 rather than 0.5; cross section thus goes up in proportion to load to the power 0.6, not the 1.0 that seems intuitively reasonable." (Vogel 2003:437)
  Learn more about this functional adaptation.
  • Steven Vogel. 2003. Comparative Biomechanics: Life's Physical World. Princeton: Princeton University Press. 580 p.
  • Koehl, M. A. R. 1984. How do benthic organisms withstand moving water. Amer. Zoologist. 24: 57-70.
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Functional adaptation

Leaves resist tearing: brown algae
 

Leaves of brown algae survive extreme mechanical battering because of their sandwiched structure.

   
  The author, speaking about a visit to the rocky coast of central Chile, says, "Whatever man put forth against the power of the sea--wood, concrete, or steel--was destroyed in the course of time. Nothing seemed able to withstand the waves. There was one exception, however: Precisely at the place where at ebb tide the full force of the surf beat against the rock, a lush vegetation of algae was thriving. With each breaker, a storm of movement ran through the jungle of fanlike or snakelike plants, which reached up to 1-2 meters in length. Their arms whirled and undulated in the suction of the current, but they survived the mechanical stress undamaged for months or years. Why weren't the algae torn off, crushed, and pounded to bits against the sharp rock? Such extreme physical stress could only be conquered by a masterful design. When I first tried to get hold of an alga, I was not able, in spite of the greatest effort, to tear off a single strand no thicker than my finger. Neither could I sever it against an edge of the rock. Only when I cut open the broad arm of a brown alga (Durvillaea antarctica) with a razor blade did its secret come to light. It was ideally constructed according to the sandwich method. Its coarse outer skins were braced against each other by a meticulously structured layer of polygonal honeycombs…Sandwich structures are construction elements in which two thin membranes are linked to each other by a very loosely and lightly built supporting layer. The flexible membranes thus become a mechanical unit which is not only much more stable, but also to a great extent protected against local breaks, cracks, and deformations. The sandwich structure owes all these advantages to the loosely assembled filler, which transmits the mechanical forces and distributes them quite evenly over large areas of the membrane surface. In this way, no stress great enough to destroy the membrane can appear anywhere." (Tributsch 1984:35-36)
  Learn more about this functional adaptation.
  • Tributsch, H. 1984. How life learned to live. Cambridge, MA: The MIT Press. 218 p.
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