ania ▁L ago on ▁Area ▁National ▁Park . ▁ ▁They ▁have ▁a ▁distinct ive ▁ge ological ▁origin ▁and ▁are ▁en closed ▁by ▁pen ins ula e , ▁sp its ▁and ▁islands , ▁leaving ▁only ▁narrow ▁connections ▁to ▁adjacent ▁bod den ▁or ▁the ▁open ▁sea . ▁F resh water ▁in flow ▁from ▁the ▁main land ▁and ▁salt water ▁in flow ▁from ▁the ▁open ▁sea , ▁which ▁depends ▁on ▁wind ▁direction ▁and ▁force ▁as ▁well ▁as ▁the ▁proxim ity ▁of ▁the ▁bod den ▁to ▁the ▁sea , ▁result ▁in ▁fl uct u ating ▁salt ▁grad ients ▁and ▁distinct ive ▁e cos ystem s . ▁ ▁During ▁the ▁L itt or ina ▁Sea ▁trans gression , ▁an ▁island ▁arch ip el ago ▁was ▁formed ▁by ▁the ▁car ving ▁of ▁narrow ▁gla cial ▁bas ins ▁and ▁channels ▁resulting ▁from ▁m elt water . ▁Bod den ▁were ▁formed ▁in ▁a ▁compar atively ▁short ▁period ▁between ▁sp its ▁and ▁off sh ore ▁sand bars . ▁These ▁shall ow ▁gla cial ▁sc o ops ▁were ▁then ▁subject ed ▁to ▁extensive ▁sed iment ation ▁during ▁the ▁Hol oc ene , ▁resulting ▁in ▁la kes ▁with ▁depth s ▁of ▁no ▁more ▁than ▁ 4 – 6 ▁metres . ▁Th erm al ▁and ▁sal ine ▁strat ification ▁is ▁extremely ▁un stable ▁under ▁these ▁conditions , ▁and ▁bod den ▁have ▁the ▁typical ▁dynamics ▁of ▁small ▁bodies ▁of ▁water ▁with ▁a ▁sea ▁connection , ▁which ▁is ▁a ▁rapid ▁filling ▁and ▁dra ining ▁due ▁to ▁tid al ▁and ▁wind ▁action , ▁and ▁in flow ▁of ▁fresh