30  Nusplingen platy limestone
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Until a few years ago, the formation time of Nusplingen platy limestone had been calculated using comparisons to the deposition period of limestone in bodies of water today. Now it has turned out, however, that Nusplingen platy limestone was built up predominantly by the carbonate exo-skeleton bearing gold algae, which is still in existence today. If the Emiliania Huxleyi, which is living today, is supplied with sufficient nutrients, it can, in only ten days, produce 0,5 – 1cm of limestone sediment. More recent findings concerning microevolutionary speciation show, moreover, that the biodiversity of the fossil sea creatures in Nusplingen platy limestone could have come about in the course of a few decades.



Rapid calcification:

Nusplingen platy limestone consists predominantly of gold algae exo-skeletons (Coccolithophorids). These minute algae (nanoplankton) floating in the sea shed a ‘scaffold’ in the form of an annular carbonate shell-cover (coccolith).

The gold algae formed the food basis for the floating small-sea lily (Saccacoma). More or less decomposed small-sea lilies are finely dispersed throughout Nusplingen platy limestone, while it remains form a major component of thick shelves.

Small-sea lilies could, given a large enough food supply, multiply on a massive scale and served as a food supply for several ammonite genera. These three life forms (gold algae, small-sea lilies and ammonites) formed an important food chain. Gold algae and small-sea lilies occurred in great numbers and became rock formers, while the ammonites constitute the most common invertebrate fossils in Nusplingen platy limestone by far (1).

The pace of sedimentation of Nusplingen platy limestone was so rapid that belemnites were embedded obliquely or even vertically. In several shale levels, dead fish are embedded, which were also buried very rapidly. This happened so fast that they did not have time to decompose.


Gigantic algae blooms:


Algal bloom  

In the summertime in cooler sea regions, today’s gold algae produce so-called algal blooms, which can cover sea areas of up to 100,000km2. We talk of an algal bloom at concentrations of more than 1,000 cells per millilitre of water. Under these conditions the algae double in number every 8.5 hours. In extreme cases, such an algal bloom can cover an area the size of England and produce a good 100 tons of lime.







Algal bloom in the Atlantic Ocean 


Rapid species formation:

The only organisms in the Nusplingen platy limestone to consistently change through various layer sequences are the ammonites. Allegedly, in the past, the microevolutionary development of ammonites from layer to layer is supposed to have proceeded substantially more slowly than is familiar to us from species living today.

The studies carried out by the biologist David Reznick and his team on small fish (Guppies – Poecilia reticulata) from predator rich and predator poor waters, show selectively generated shape changes after only 18 generations (2). They thereby developed up to 10 million times faster than suggested by the fossil sequence.

Rapid species formation was also observed as taking place under conditions of (enormous) environmental stress. For instance in plants growing on mining waste heaps contaminated with heavy metal (3), or mice exposed to environmental toxins (4).

A further example of microevolutionary development are the species rich cichlid faunas in Lake Malawi, which have come into existence in the last 200 years. Disturbed environmental conditions such as the lake’s documented drying out phases have contributed to this, whereby, under different selection pressures, with basic forms with a very diverse genotype (genetic Polyvalence), new founder populations constantly came into being (5).


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References:

(1) Manfred Stephan, Zur Bildungsdauer des Nusplinger Plattenkalks, Studium Integrale, April 2003, S. 12–20, http://www.wort-und-wissen.de/index2.php?artikel=sij/sij101/sij101-2.html.
(2) David N. Reznick, Frank H. Shaw, F. Helen Rodd und Ruth G. Shaw, Evaluation of the rate of evolution in natural populations of guppies (Poecilia reticulata), Science 275, 28. March 1997, Pages 1934–1937.
(3) Reinhardt Junker, Prozesse der Artbildung, in S. Scherer (HG)´s Buch „Typen des Lebens“, Berlin, 1993, Pages 31–45.
(4) Silvia Garagna, Maurizio Zuccotti, Carlo Alberto Redi und Ernesto Capanna, Trapping speciation, Nature 390, 20. November 1997, Pages 241–242.
(5) J. Fehrer, Explosive Artbildung bei Buntbarschen der ostafrikanischen Seen, Studium Integrale 1997/4, Pages 51–55.
 
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