05.01.2013 Views

technical guidance documents - Institute for Health and Consumer ...

technical guidance documents - Institute for Health and Consumer ...

technical guidance documents - Institute for Health and Consumer ...

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

APPENDIX XIV<br />

Appendix XIV In<strong>for</strong>mation on the difference in diversity between saltwater<br />

<strong>and</strong> freshwater<br />

The greater diversity of species in saltwaters 11 compared to freshwaters has been recognised <strong>for</strong><br />

many years. In the key work “The Seas”, Russell <strong>and</strong> Yonge (1928) state that “The sea is far<br />

richer in different <strong>for</strong>ms of life than the l<strong>and</strong> or freshwater, many groups of animals being<br />

exclusively marine”. This view has been consolidated in other publications which have based the<br />

difference on a number of factors including the fact that life originated in the seas <strong>and</strong> they have<br />

been well populated since the earliest fossil records (Tait, 1978).<br />

The results below show recent comparative data on freshwater <strong>and</strong> saltwater species diversity<br />

generated <strong>for</strong> the Danish Environmental Protection Agency by the Zoological Museum <strong>and</strong> the<br />

Department of Evolutionary Biology at University of Copenhagen.<br />

Taxonomic group No. of species Comments<br />

Porifera 4,850 (150 in freshwater)<br />

Ctenophora 50 (Exclusively marine)<br />

Cnidaria 7,000 (Exclusively marine)<br />

Tubellaria 2000 (1000 in freshwater)<br />

Trematoda 6,000 (internal parasites) ------<br />

Cestoda 3,500 (internal parasites) ------<br />

Nemateans 900 (Predominantly marine)<br />

Gastrotricha 150 (Marine <strong>and</strong> fresh water)<br />

Nematoda 5,000 (15,000 described species in total<br />

including parasites <strong>and</strong> terrestrial, marine<br />

<strong>and</strong> freshwater <strong>for</strong>ms)<br />

Nematomorpha 4 (316 in freshwater)<br />

Achantocephala 1,150 (internal parasites) -----<br />

Kinorhyncha 150 (Exclusively marine)<br />

Priapulida 17 (Exclusively marine)<br />

Loricifera 100 (Exclusively marine)<br />

Gnatostomolida 80 (Exclusively marine)<br />

Rotifera 100 (1,400 in freshwater)<br />

Polychata 5-10,000 (1000 in freshwater)<br />

Oligochaeta ------ (Many species; mainly in freshwater)<br />

Echinodermata 7,000 (Exclusively marine)<br />

Brachiopoda 300 (Exclusively marine)<br />

Echiura 140 (Exclusively marine)<br />

Sipunculida 350 (Exclusively marine)<br />

Pogonophora 120 (Exclusively marine)<br />

Tardigrada (Taxonomic group discovered a few<br />

11 Except those where there are extremes of environmental conditions<br />

327

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!