In:
Climate of the Past, Copernicus GmbH, Vol. 15, No. 3 ( 2019-05-23), p. 927-942
Abstract:
Abstract. A new high-resolution deglacial and Holocene sea surface temperature (SST)
reconstruction is presented for the Alboran Sea (western Mediterranean),
based on Mg∕Ca ratios measured in the planktonic foraminifera Globigerina bulloides. This new
record is evaluated by comparison with other Mg∕Ca SST records and
previously published alkenone SST reconstructions from the same region for
both the Holocene and glacial periods. In all cases there is a high degree
of coherence between the different Mg∕Ca SST records but strong
discrepancies when compared to the alkenone SST records. We argue that
these discrepancies are due to differences in the proxy response during
deglaciation which we hypothesize to reflect a resilience strategy of G. bulloides,
changing its main growth season, and consequently Mg∕Ca records a shorter
deglacial warming than alkenones. In contrast, short-term Holocene SST
variability is larger in the Mg∕Ca SST than in the alkenone SST records.
We propose that the larger Mg∕Ca SST variability is a result of spring
temperatures variability, while the smoothed alkenone SST variability
represents averaged annual temperatures. The Mg∕Ca SST record
differentiates the Holocene into three periods: (1) the warmest SST values
occurred during the Early Holocene (11.7–9 cal. kyr BP), (2) a continuous
cooling trend occurred during the Middle Holocene that culminated in the
coldest Holocene SST having a double cold peak structure centred at around
4.2 cal. kyr BP, and (3) the Late Holocene (4.2 cal. kyr BP to present) did not follow any
clear cooling/warming trend although millennial-scale oscillations were
enhanced. This SST evolution is discussed in the context of the changing
properties in the Atlantic inflow water associated with North Atlantic
circulation conditions and also with local hydrographical and atmospheric
changes. We propose that a tight link between North Atlantic circulation
patterns and the inflow of surface waters into the Mediterranean played a
major role in controlling Holocene climatic variability of this region.
Type of Medium:
Online Resource
ISSN:
1814-9332
DOI:
10.5194/cp-15-927-2019
DOI:
10.5194/cp-15-927-2019-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2019
detail.hit.zdb_id:
2217985-9
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