Complex controls on ostracod palaeoecology in a shallow coastal brackish‐water lake: implications for palaeosalinity reconstruction

1. The low‐Mg calcite shells of Ostracoda (Crustacea) are often well preserved in the sediments of alkaline lakes. In coastal waters that have undergone large temporal changes in salinity, ostracod assemblages preserved in the sediment record have been used to reconstruct palaeosalinity, often assum...

Full description

Saved in:
Bibliographic Details
Published in:Freshwater biology 2010-12, Vol.55 (12), p.2484-2498
Main Authors: HOLMES, JONATHAN, SAYER, CARL D, LIPTROT, ELLIE, HOARE, DANIEL J
Format: Article
Language:English
Subjects:
brackish lake
calcite
coastal water
Crustacea
eutrophication
Freshwater
habitat destruction
Hickling Broad
lakes
Marine
Ostracoda
ostracods
palaeolimnology
paleoecology
Salinity
salt tolerance
temporal variation
water quality
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:1. The low‐Mg calcite shells of Ostracoda (Crustacea) are often well preserved in the sediments of alkaline lakes. In coastal waters that have undergone large temporal changes in salinity, ostracod assemblages preserved in the sediment record have been used to reconstruct palaeosalinity, often assuming that salinity is the only significant control on the faunas. 2. We evaluate the performance of ostracods as palaeosalinity indicators in Hickling Broad, a shallow brackish coastal lake in Norfolk, U.K., by comparing fossil ostracod assemblages covering two centuries with geochemical inferences and instrumental records of past salinity and water composition along with other palaeolimnological indicators. 3. Despite large changes in the salinity of the lake and the supposed salinity sensitivity of ostracods, the fossil ostracod assemblages do not clearly reflect the salinity trends inferred from the other independent data. Rather, a complex series of changes has occurred in the lake over the past 200 years and factors other than salinity, including eutrophication, toxicity and associated complex alterations in habitat availability have probably influenced ostracod assemblages. In contrast, there is a good broad agreement between inferred or measured salinity and the trace‐element chemistry of ostracod shells. 4. We conclude that ostracod faunas may not always provide unambiguous palaeosalinity records and should therefore not be used to reconstruct salinity changes except as part of a multi‐proxy investigation that includes other palaeoecological and/or geochemical indicators.
ISSN:0046-5070
1365-2427
DOI:10.1111/j.1365-2427.2010.02478.x