Re: Purbeck Beds

[Donna Braginetz <quailspg@frii.com>]

"Richard W. Travsky" wrote:
> 
> Looking up "Cienaga Grande de Santa Marta", several hits. This link
> seemed to exlpain a bit:
> 
> http://data.ecology.su.se/MNODE/South%20America/cienegagrande/cienegagrandebud.html
> 
>  The Cienaga Grande de Santa Marta (CGSM) is a lagoon-delta ecosystem
>  which forms the exterior delta of the Magdalena River. [...] This system
>  can be classified as a type I setting (river-dominated, arid, with low
>  tidal amplitude) containing fringe, basin, and riverine mangroves (Thom
>  1982). [...] The coastal climate zone is arid tropical, with 6-7
>  dry-months a year
   [snip] 
>  Freshwater diversion from the lagoon-delta complex in
>  this arid coastal region has resulted in hypersalinization of mangrove
>  soils   [...]


So I guess the Purbeck area was an arid coastline. I'll keep my eyes
peeled for "arid lagoon" ecosystems when I travel.

Thanks for the lead. I checked out the website. The area is on the
northern coast of Columbia and it looks like it's become a poster child
for environmental impact statements. Read on:


 "The CGSM has been impacted by the construction of a coastal highway
and a road levee along the Magdalena River...  The construction of these
two roads has altered the natural flow of marine and freshwaters... and
the resulting water diversion has resulted in severe environmental
damage to the mangrove-lagoon ecosystem.  Most of the past alterations
in coastal hydrology were due to re-diversion of freshwater associated
with highway construction, expansion of agriculture (cattle farming and
rice), and urban development.  Freshwater diversion from the
lagoon-delta complex in this arid coastal region has resulted in
hypersalinization of mangrove soils... leading to a die-off of almost
27,000 ha in a 36-year period... The estuarine regions were surrounded
until around 1960 by approximately 52,000 ha of mangrove wetlands."

The rest of the page describes restoration projects begun in 1993.


- DONNA BRAGINETZ