Thapsus was one of the Roman Empire's largest harbors and is situated next to
an easily defended promontory on Tunisia's coast in northern Africa. It was
provided with a huge stone and cement breakwater mole that extended almost 1 km into the sea. We examined sedimentological and micropaleontological
proxies from 14C-dated core material and shifts in microfauna and
macrofauna community structure to infer patterns of sediment dynamics and
the chronology of events that shaped the coastal evolution in the Dzira
Lagoon at Thapsus over the past 4000 years. The sedimentological and faunal record of environmental changes reflect a sequence of events that
display a transition from an open to a semi-closed lagoon environment. At
around 4070 cal yr BP and again between 2079 and 1280 cal yr BP, the data reveal two transgressive events and a deposition of sandy sediments in
a largely open marine lagoon environment. The transgressive sands overlay
marine carbonate sandstones that are upper Pleistocene in age. A gradual
closure of the lagoon from 1280 cal yr BP until today is indicated by
decreasing species richness values, lower abundances of typical marine taxa,
and increasing percent abundances of fine-grained sediments. The
environmental transition from an open to a closed lagoon setting was also
favored by the construction of an extensive harbor breakwater mole, changes
in longshore current drift patterns, and the formation of an extensive
sand spit.
Introduction
The ancient city of Thapsus, situated on the east coast of Tunisia between
Sousse and Sfax, was founded by the Phoenicians and served as a major
trading hub between the Strait of Gibraltar and the Levant region of the
eastern Mediterranean (Fig. 1a). Thapsus was established around Rass Dimass,
a cape extending into the sea providing natural shelter for vessels and
enabling safe anchorage for loading and discharge of cargo. When the
Phoenicians fought against the Romans in the Punic Wars, Thapsus sided with
Roman emperors (Gordianus I, II, II) and was fortified with an enormous
harbor infrastructure, an amphitheater, and a huge breakwater mole (Davidson
and Yorke, 2014). The massive concrete and stone breakwater structure
extended almost 1 km into the sea (Fig. 1e) and represents one of the
Roman Empire's longest harbor structures known to date (Dallas and Yorke,
1968; Yorke, 1967). Due to erosion by waves, pillaging
for local house constructions, a rising sea level, and the erection of a
small fishing port on top of the ancient harbor structure, only about 100 m of the original breakwater mole remains above water today (Slim et
al., 2004).
In the north and current-protected lee of Rass Dimass and prior to the
construction of the breakwater mole, the prevailing current drift action
resulted in the formation of a long sand spit (Fig. 1b–c). Today, the
sand spit is attached to the land and stretches over 4 km, with a
width of 200 m, and forms a barrier (Dzira Island) composed of beaches and
dunes that separates a shallow lagoon (Dzira Lagoon) from the open Monastir
Bay. The extremity NW of the sand spit shows several hooks reflecting
various stages of its development (Fig. 1c). In addition, between the Dzira
sand spit and Kuriat Island, several sand spits, shoals, and swash bars occur
(Fig. 1f). The shallow lagoon served as a natural harbor during antiquity
(Fig. 1e; Davidson and Yorke, 2014) and was illustrated in Andrea Palladio's
16th century treatise of the Battle of Thapsus (Fig. 1f; Giocondo and
Palladio, 1567). At the southern entrance to the lagoon, a tidal channel,
related to anthropogenic actions, allowed a connection
with the open sea for several years before its recent clogging (Fig. 1c–d). The massive breakwater mole was built to add the existing natural shelter.
However, dynamic coastal processes including littoral drift, lateral
movements of sediments, and a rising sea level continued to shape the
coastal habitats at Thapsus.
Within Monastir Bay, sediments settle in a comparatively protected
environment, and along the shallow bay shore (0 to 2 m depth) the bottom is
covered by medium sand. Sediment transport is mainly from north to south and
vice versa, driven by longshore drift and rip currents. Both currents are
generated by wind and swell, especially by north to northeast waves which
transport the finest sediment.
Monastir Bay is characterized by wind speeds that range between 1 and 5 m s-1.
Prevailing wind directions are W, NNE, and E with occurrence probabilities
of 10.7 %, 8.5 %, and 7.6 %, respectively (Souissi et al., 2014).
Tides at Monastir Bay are semi-diurnal and generally of low amplitude.
Average tidal ranges are 30 cm but occasionally reach 70 cm. Wind-induced
currents are of the order of 5 to 10 cm s-1. Over the entire Bay of Monastir
and in particular around the Kuriat Islands, the predominant dynamic agent
is swell. At the level of the Kuriat Islands, the coastal currents run along
the series of shoals that link the Kuriat–Cogniliera archipelago with the
shores of Teboulba.
In this study we provide high-resolution sedimentological and
micropaleontological analyses of three radiocarbon-dated cores to
reconstruct the coastal evolution around the ancient harbor of Thapsus. Our
objectives were (1) to trace the environmental history of lagoonal habitats,
(2) identify the impact of anthropogenic activities (breakwater mole
construction) on coastal sediment dynamics, and (3) correlate major events
with those recognized at other sites along the Mediterranean coast.
Materials and methods
To reconstruct the environmental evolution at Thapsus, a multi-proxy
analysis was conducted on three cores (RD1, RD3, and RD8) recovered from the
intertidal zone of Dzira Lagoon (for core locations see Fig. 1c). At the
time of drilling, core areas for sites RD3 and RD8 were covered with 5 cm and
for RD1 with 20 cm of water.
Cores were drilled with PVC (polyvinyl chloride) tube coring devices (core diameter 60 mm). In
the laboratory, cores were cut in half longitudinally, photographed, and
analyzed for sediment types, grain size, texture, structure, color, organic
constituents, and microfossil and macrofossil content. In general, samples for
micropaleontological analysis (benthic foraminifera) were taken at 10 (RD1
and RD3) and 15 cm intervals (core RD8) with a few additional samples at
major transitions.
For granulometric analysis, a total of 42 samples were taken at 10 cm
intervals from cores RD1 (11 samples), RD3 (14 samples), and RD8 (17 samples).
Grain size measurements were carried out on 2 g of dry sediment, which
underwent wet sieving using a 2000 µm mesh sieve to separate the coarse
from the fine fraction (<2000µm). The fine fraction was then
analyzed using a Malvern Mastersizer 3000 Laser Particle 139 Analyzer. One-half of each core is archived and stored at the GEOGLOB Laboratory at Sfax
University (Tunisia).
Radiocarbon datings (14C) were carried out at the Institute of Geology
and Mineralogy at the University of Cologne, Germany. All samples were
prepared following the standard procedure described in Délibrias (1985).
Only intact mollusks, without sediment filling, were selected for dating.
The shells were mechanically cleaned and leached with diluted HCl to remove
portions of the shell matrix to prevent cross-reactions (Vita-Finzi and
Roberts, 1984). Data calibration was performed by using MARINE 20
calibration curves (Heaton et al., 2020) and the CALIB radiocarbon
calibration software (version 8.2), with a marine reservoir effect of
390±85 years and ΔR=-104±109 years (Hunt et al., 2020;
Siani et al., 2000) for the Mediterranean Sea. The ages discussed below are
expressed as median ages (cal BP and cal CE; Table 1).
14C ages obtained from bivalves and gastropods from cores RD1,
RD3, and RD4.
CoreCoordinatesTotalSamplingStudied materialAge 14CRange 1σRange 2σMedianMedian ageLaboratorydepthdepthyr BP(68.3 %)(95.4 %)ageBCE/CEcode(cm)(cm)cal yr BPcal yr BPcal yr BPRD135∘37′37.80′′ N 11∘2′45.10′′ E9076Cerithium vulgatum2472 ± 361713–19481743–23702079129 BCECOL6148.1.1RD335∘37′55.17′′ N 11∘2′38.17′′ E125120Hydrobia trochulusLoripes lucinalis3147 ± 532747–30592604–32562913963 BCECOL4849.1.1RD835∘38′5.31′′ N 11∘2′28.98′′ E18057–65Cerithium vulgatumCerastoderma glaucum1779 ± 341138–1407997–15451280670 CECOL6150.1.1108–116Cerithium vulgatumCerastoderma glaucum2628 ± 362103–24372628–19532273323 BCECOL4852.1.1163–166Cerithium vulgatumCerastoderma glaucum4076 ± 383893–42373729–440540702120 BCECOL6151.1.1
For the identification of the gastropods and bivalves, we used the reference
catalogues of Bouchet and Rocroi (2005, 2010). For micropaleontological
analyses, core samples were dehydrated at 40 ∘C, and their dry
weight was recorded. Samples were then washed over 63 µm mesh sieves
and dried at room temperature. At least 300 specimens of benthic
foraminifera were picked from each sample. Foraminifera were identified to
species level and counted (Fig. 2, Table 2, Files S1–S3 in the Supplement) and then
standardized to 2 g of dry sediment for each sample. Foraminifera records
include all taxa. For the identification of species, we follow the taxonomic
catalogues provided by Cimerman and Langer (1991) and Langer and
Schmidt-Sinns (2006). The sample material is stored in the GEOGLOB
laboratory of the University of Sfax, Tunisia (Mohamed Kamoun and Chahira Zaibi).
In order to reconstruct environmental changes along the coastline, benthic
foraminifera were categorized according to their ecological (Table 3) and
microhabitat preferences (Murray, 2006; Langer, 1988, 1989, 1993; Langer et
al., 1998; Hayward et al., 1999, 2021).
Scanning electron microscopy (SEM) photographs of foraminifera species found in sediments from
cores RD1, RD3, and RD8. The scale bar is 100 µm for all specimens
illustrated.
(1)Elphidium hawkesburiense (Albani 1974).
(2)Elphidium advenum (Cushman 1922).
(3)Elphidium aculeatum (d'Orbigny 1846).
(4)Elphidium sp. 1.
(5)Elphidium macellum (Fichtel and Moll, 1798).
(6)Elphidium cf. E. limbatum (Chapman, 1907).
(7–9)Rosalina bradyi (Cushman 1915).
(10–11)Rosalina macropora (Hofker, 1951).
(12–13)Rosalina sp. 1.
(14)Siphonina tenuicarinata Cushman, 1927.
(15)Discorbina sp. 1.
(16)Neoconorbina sp. 1.
(17)Ammonia venecpeyreae Hayward and Holzmann, 2019.
(18)Discorbinella sp. 1.
(19)Haynesina sp. 1.
(20)Helenina anderseni (Warren, 1957).
(21)Quinqueloculina tantabiddyensis Parker, 2009.
(22)Lachlanella variolata (d'Orbigny, 1826).
(23)Quinqueloculina sp. 2.
(24)Siphonapertadilatata (Le Calvez & Le Calvez, 1958).
(25)Siphonaperta sp. 1.
Five groups were recognized: (I) ammoniid foraminifera as indicators for
particularly shallow, intertidal, or stressed environmental conditions; (II) elphidiid foraminifera as indicators for shallow, nearshore coastline
habitats; (III) miliolids as indicators for shallow coastline habitats; (IV) peneroplids as indicators for the presence of well-oxygenated seagrass or
algal habitats; and (V) rosalinid foraminifera as indicators for algal or
other hard-substrate environments. To compute and illustrate biocenotic
parameters (abundance, number of individuals, species richness – NS,
dominance – D, Shannon – H, and equitability – E indices; Pielou, 1966) the
software package PAST V 2.04 (Hammer et al., 2001) was used (Files S1, S2, S3).
Foraminifera taxa recorded in sediment samples from cores RD1, RD3,
and RD8 in alphabetic order.
Environmental preferences of dominant species and genera of benthic
foraminifera recorded along cores RD1, RD3, and RD8.
Genus/speciesEnvironmental preferencesReferencesAmmonia convexaRestricted to intertidal environments. Preference for mud and muddy sand substrates and tolerates a wide range of normal marine to hyposaline salinities. Stress-tolerant and used here as an indicator for the closure of the lagoon.Saad and Wade (2016), Bird et al. (2020), Hayward et al. (2021), Blanc-Vernet et al. (1979)Asterigerinata mamillaAssociated with shallow phytal substrates or sandy bottoms in well-oxygenated environments.Langer (1988, 1993), Frezza and Carboni (2009)Buccella granulataIndicator species for shallow-water habitats (0–100 m) characterized by fine sands and mud. Mostly infaunal and rarely as epiphyte.Avnaim-Katav et al. (2015), Blanc-Vernet et al. (1979), Morigi et al. (2005), Murray (2006), Calvo-Marcilese and Langer (2012)Cibicides refulgensEpiphyte on various types of algae and seagrasses with a preference for shallow coastal, nearshore habitats. Also present on hard substrates such as mollusk shells and pebbles.Langer (1988, 1993), Oflaz (2006)DiscorbinellaIndicator taxon for infralittoral to circalittoral shallow nearshore environments including tidal channels. Occurs together with other oxic species such as Cibicides, Planorbulina, and smaller miliolidsKaminski et al. (2002), Oflaz (2006), Armynot du Châtelet et al. (2018)Elphidium crispum, Elphidium fichtellianum, Elphidium jenseni, Elphidium macellum, Elphidium sagrumMost elphidiid foraminifera are indicators for shallow, nearshore environments that are well-connected to the open ocean. Often epiphytic on phytal substrates and within rhizomes of Posidonia. Some species have microhabitat preferences for sandy and muddy substrates and occur over a wide range of habitats (brackish–hypersaline marshes and lagoons, inner shelf settings).Murray (2006), Langer (1988, 1993), Langer et al. (1990, 1998)Haynesina depressulaMostly infaunal in muddy and silty shallow-water environments. Occurs over a range of habitats from brackish, intertidal to lagoon environments and tolerates a wide range of salinity and temperature conditions.Calvo-Marcilese and Langer (2010), Langer et al. (1990), Murray (2006)Laevipeneroplis karreri, Peneroplis planatus, Peneroplis pertususLarger symbiont-bearing foraminifera with preferences for various types of phytal substrates in shallow-water settings. Living species in the Mediterranean Sea are mostly restricted to depth between 0 and 50 m.Cimerman and Langer (1991), Langer (1988, 1993), Murray (2006)Siphonaperta agglutinansOccurs frequently in rhizome habitats of the seagrass Posidonia oceanica.Langer (1988, 1993), Langer et al. (1998)NeoconorbinaEpiphytic, common in Mediterranean infralittoral environments, typical taxa in well-oxygenated, shallow-marine environments covered by algae or seagrasses. Also present in inner shelf environments and on hard substrates.Cimerman and Langer (1991), Dimiza et al. (2016), Frezza and Carboni (2009), Langer (1988, 1993), Murray (2006)Quinqueloculina seminulum, Quinqueloculina vulgaris, Triloculina trigonulaMiliolids occur over a wide range of shallow-water habitats, often observed on phytal substrates but also shallow infaunal. Preferences for well-oxygenated shallow and open-shelf settings covered by algae and seagrasses.Langer (1988, 1993), Murray (2006), Sgarrella and Moncharmont Zei (1993)Rosalina bradyi, Rosalina macroporaMostly epiphytic in Mediterranean shallow-water environments. Present on algae, seagrasses, and rhizomes in well-oxygenated habitats.Langer (1993), Frezza and Carboni (2009), Langer et al. (2013)
To determine the structure in the foraminiferal data, an R-mode cluster
analysis was performed with the paired group algorithm using the Bray–Curtis
dissimilarity for species constituting ≥2 % in at least one sample.
Cluster analysis was performed on the foraminiferal sample data recorded in
core RD3. Core RD3 was selected herein because it outperformed the other
cores in microfauna richness. Cluster analysis is a large-scale analytical
procedure to detect structural entities within complex data sets. This
entails data mining and pattern discovery. For the cluster analysis, the
data were imported into PAST software and analyzed. This technique groups
together species with similar occurrence records in cluster assemblages and
reveals a typology of environmental signatures embedded in a hierarchical
dendrogram.
Core lithology and microfaunal recordCore RD1
Core RD1 has a total length of 90 cm, contains the highest foraminiferal
species richness and abundance values, and is subdivided into three
lithological units (Fig. 3, File S1, Table S1 in File S4).
Unit U1, from 90 to 70 cm, is composed of dark fine sands rich in organic
matter. It contains mollusks, such as Cerithium vulgatum, Hydrobia trochulus, and Loripes lucinalis, as well as Posidonia seagrass debris and
reveals the highest percentage of very fine sand (15 %), silt, and clay
(10 %). The foraminiferal assemblages in this interval (70–80 cm, Figs. 4,
5) are characterized by moderate species richness and a mixture of nearshore
(Ammonia spp.), shallow-water (miliolids), and typical epiphytic foraminifera
(Rosalina spp., peneroplids). At a core depth of 75 cm (upper part of unit U1), an
age of 2079 cal yr BP was obtained by 14C radiocarbon dating.
Unit U2 (70 to 35 cm), mainly composed of medium and fine sand, contains
various centimetric bands of gray sand that is rich in Posidonia debris and shows a
peak of coarse quartz sand at a depth of 50 cm. Within the lower part of
unit 2 (70–50 cm), foraminiferal species richness continues to rise and
reaches its maximum at a core depth of 50 cm. The foraminiferal fauna in
this interval is marked by nearshore (Ammonia spp.), shallow-coastal (Elphidium spp.,
miliolids), and abundant epiphytic taxa (Rosalina spp., peneroplids),
indicative of an unrestricted connection of the tidal channel and/or navigation
channel to the open sea. A peak of coarse sand recorded at 50 cm core depth
is marked by a decrease in species richness and in the composition of
foraminiferal biota. At 40 cm depth, species richness drops rapidly and
reaches its lowest value, while Ammonia spp. constitutes more than 40 % of the
benthic fauna. Peak abundances of Ammonia spp. and particularly low species
richness values suggest a tendency towards more restricted conditions and
are indicative of environmental changes that were initiated after the
deposition of coarse sands.
Lithologic columns and lithological units, calibrated median ages
(yr BP), and textural components (percentages of grain size classes: coarse
sand, medium sand, fine sand, very fine sand, and silt–clay) for cores RD1,
RD3, and RD8.
Foraminifera data for core RD1: depth of core, calibrated median
ages (yr BP), lithological units, vertical distribution of foraminifera,
and environments.
Unit U3, from 35 cm to the sediment surface, is characterized by a mixture
of fine (25 %) and medium sand (60 %) and lacks very fine sand, silt, and
clay. From 30 to 10 cm core depth, foraminiferal species richness rises
above 30 but drops to around 20 at 5 cm depth. At the same time, percent
abundances of Ammonia spp. increase towards the core top, while the total number of
individuals decreases continuously and reaches minimum values just below the
sediment surface. Both the decrease in species richness and individual
numbers and the increase in ammoniid foraminifera suggest that the
connection with the open ocean continued to deteriorate.
Foraminifera data for core RD1: depth of core, calibrated median
ages (yr BP), lithological units, vertical distribution of foraminiferal
groups, biocenotic parameters, diversity indices, and environments.
Core RD3
Core RD3 has a total length of 130 cm and exhibits four different lithological
units (Fig. 3, File S2, Table S2 in File S4). Unit Ul1 comprises
the interval from 130 to 110 cm and mainly consists of dark, medium, and fine
sands that are rich in mollusks (Cerithium vulgatum, Hydrobia trochulus, Loripes lucinalis) and Posidonia seagrass debris. At a core depth
of 120 cm, radiocarbon dating revealed an age of 2913 cal yr BP for unit
Ul1. Along the entire RD3 core, the silt and clay fractions are highest in
unit Ul1. Species richness in Ul1 ranges between 20 and 30, a range that
remains almost constant throughout the core (Figs. 6, 7). The foraminiferal
fauna in unit Ul1 is dominated by Ammonia spp. and Rosalina spp. but also contains various
species of Elphidium and miliolid foraminifera. The diverse composition suggests a
shallow nearshore setting with free connections to the open sea.
Foraminifera data for core RD3: depth of core, calibrated median
ages (yr BP), lithological units, vertical distribution of foraminifera,
and environments.
Foraminifera data for core RD3: depth of core, calibrated median
ages (yr BP), lithological units, vertical distribution of foraminiferal
groups, biocenotic parameters, diversity indices, and environments.
Unit Ul2 (110–90 cm) is composed of gray sands that are rich in mollusks.
Above Ul2, white sands were deposited and constitute unit Ul3. Unit Ul3
extends from 90–35 cm core depth and contains abundant intact and fragmented
shells of Cerithium vulgatum and Dentalium sp. Towards the top of this unit, the percentage of medium
and fine sand gradually increases and reaches values of 65 % and 20 %,
respectively. Species richness within units Ul2 and Ul3 ranges between 20 and
30, but the number of individuals decreases continuously towards the top of
the core. The faunal assemblages recorded in Ul2 and Ul3 are heterogenous,
reveal percent abundance variations between coastal water indicators
(Ammonia spp.), elphidiids, and Rosalina spp., and display peak abundances of epiphytic
peneroplids and smaller miliolids between 70 and 40 cm core depth. Peak
abundances of peneroplid and miliolid foraminifera coincide with lowest
values of ammoniid foraminifera and suggest a free connection to the open
sea. However, abundance variations of peneroplid–miliolid and ammoniid
foraminifera suggest that the free connection to the open ocean varied over
time.
The top portion of the core (35–0 cm) represents unit Ul4 and comprises
white sands that contain abundant pebbles and mollusks (Loripes lucinalis, Abra alba, Cerithium vulgatum, Potamides sp., Natica sp.).
Within unit Ul4, coarse sands gradually decrease and the deposits are
dominated by medium (70 %) and fine (20 %) sands. The foraminiferal
fauna of unit Ul4 is marked by low species richness and abundance values,
low percent abundances of smaller miliolids, and continuously rising rates of
coastal indicator foraminifera (Ammonia spp.). The faunal shift recorded in unit
Ul4 suggests a tendency towards more restricted conditions with a limited
exchange of coastal waters with the open-ocean environment.
Core RD8
Core RD8 has a total length of 190 cm; unlike RD1 and RD3 and due to its
length, it reached the white upper Pleistocene carbonate sandstones at its
base (Fig. 3). The sediments deposited above the Pleistocene sandstones
exhibit four different lithological units (UL1–UL4). Unit UL1, from 190 to 150 cm, is composed of dark fine sands that are rich in mollusk fragments,
Posidonia seagrass debris, and Tyrrhenian lithoclasts. Mollusk shells collected at a
core depth between 163 and 166 cm were dated and revealed an age of 4070 cal yr BP. Unit UL1 is rich in silt–clay (15 %) and very fine sand (20 %), a
pattern that continues throughout the rest of the core. The foraminiferal
biota (Figs. 8, 9; File S3, Table S3 in File S4) of unit UL1 contain abundant individuals of the coastal shallow-water genus
Ammonia, largely absent in this unit. Both the number of species and the number of
individuals per gram dry sediment are comparatively high, indicative of a
shallow, well-oxygenated habitat that is connected to the open ocean.
Foraminifera data for core RD8: depth of core, calibrated median
ages (yr BP), lithological units, vertical distribution of foraminifera,
and environments.
Gray sands constitute unit UL2 (150 to 130 cm) and show a decrease in the
silt–clay and very fine sand fraction as well as an increase in medium sands
(35 %). Unit UL2 hosts diverse, species-rich, and heterogenous assemblages
of foraminifera, indicative of a continuation of a free connection to the
open sea.
Unit UL3 (130 to 30 cm) differs from other units by the enrichment of coarse
sand (20 %) and Posidonia seagrass debris. Mollusk shells used for radiocarbon
dating revealed an age of 2273 and 1280 cal yr BP for sediments deposited at
108–116 and 57–65 cm core depth, respectively. Unit UL3 is characterized by an increase in medium
(40 %) and coarse sands (20 %). Within the lower portion of this unit
(120–70 cm core depth), epiphytic peneroplids are strikingly more abundant
and contribute ∼ 10 % to the total assemblage. At the same
time, the abundance of shallow coastal water indicators (Ammonia spp.) decreases.
Above 65 cm core depth, peneroplid foraminifera disappear almost completely,
the number of ammoniid foraminifera increases, and the species richness and
the number of individuals per gram sediment continue to decrease. The
observed shift from high- to low-diversity assemblages, the lack of epiphytic
peneroplids, and the increase in specimens of Ammonia spp. suggest a transition
from open-ocean to more restricted environmental conditions.
Foraminifera data for core RD8: depth of core, calibrated median
ages in BP, lithological units, vertical distribution of foraminiferal
groups, biocenotic parameters, diversity indices, and environments.
White sands rich in mollusk shell debris constitute unit UL4 (30 cm to core
top). This unit is characterized by a prominent decrease in coarse sands and
an enrichment of the fine sand fraction (40 %). The foraminiferal fauna
recovered from unit UL4 is marked by low species richness values, a lack of
peneroplids, abundant specimens of Rosalina spp., Ammonia spp., Elphidium spp., and low numbers of
individuals per gram dry sediment. All parameters show an increasing
constriction of the lagoon and a worse connection with the open ocean.
Cluster analyses of foraminifera taxa
Cluster analysis was performed to obtain additional paleoenvironmental
information (Figs. 10, 11) and included all taxa from core RD3 constituting
at least 2 % in one sample. The 2 % limit was selected to reduce
background noise from rare species and resulted in a total of 39 taxa to be
included. The total number of species recorded in core RD3 was 50. Results
of the R-mode analysis revealed the presence of six clusters (CL1 to CL5, Fig. 10a). Cumulative percentage data for all species contributing to individual
clusters are provided across the RD3 core (Fig. 10b).
R-mode cluster analysis for core RD3 showing clusters CL1 to CL5.
Relative abundances of all major species along core RD3.
Cluster 1 (CL1) occurs continuously throughout the core and shows peak
species richness values between 50 and 20 cm. It contains Ammonia sp. 2 (3 %),
Ammonia sp. 3, Peneroplis pertusus (3 %), Peneroplis planatus (3 %), Elphidium crispum (2 %), Coscinospira hemprichii and various robust miliolids
(Lachlanella variolata (3 %), Quinqueloculina sp. 1, Quinqueloculina sp. 2, Quinqueloculina ungeriana (3 %), and Triloculina trigonula (5 %). The species recorded are
indicative of a particularly shallow, current-dominated environment
characterized by coarse-grained sediments (García-Sanz et al., 2018;
Buosi et al., 2012).
Cluster 2 (CL2) is represented by Quinqueloculina limbata (5 %), Siphonaperta agglutinans (5 %), Rotorbis auberii (2.5 %), and
Spiroloculina antillarum (3 %). It shows the highest percentages (10 %–17 %) in the interval between
60 and 20 cm and is indicative of an open lagoon environment and a free
connection to the sea.
Subcluster 3A (CL3A) contains abundant elphidiids, Cibicides refulgens (7 %), Elphidium jenseni,
Discorbinella sp. 1, Elphidium macellum (9 %), Elphidium sp. 1, Haynesina depressula (6 %), Siphonaperta dilatata (9 %), and Rosalina macropora (5 %). Haynesina depressula has frequently been
reported from muddy sands of intertidal environments (Langer, 1988). These
taxa occur continuously throughout the core. Maximum abundances were
recorded in the lower part of the core (130–60 cm, 37 %).
Subcluster 3B (CL3B) contains Quinqueloculina vulgaris (10 %), Quinqueloculina seminulum (10 %), Ammonia sp. 1 (15 %), Rosalina bradyi (15 %),
Ammonia aberdoveyensis (20 %), and Elphidium sagrum (10 %). CL3B shows the maximum richness (50 %) between
110 and 60 cm. To the top of the core the richness is around 37 %.
Subclusters 3A and 3B are interpreted to represent nearshore environments.
Cluster 4 (CL4) occurs continuously throughout the core. It contains motile
epiphytic species (Buccella granulata) and a range of temporarily attached forms
(Asterigerinata, Neoconorbina). It shows sporadic occurrences (6 %) in its basal part between 130
and 80 cm. Cumulative percentage data decrease markedly between 70 and 30 cm. Taxa of cluster CL4 are indicative of phytal substrates and sandy
sediments (Frezza and Carboni, 2009; Blanc-Vernet et al., 1979; Langer,
1993).
Cluster 5 (CL5) is discontinuously present along the core and includes
Quinqueloculina sp. 3 (between 50 and 30 cm, 3 %), Elphidium sp. 2 (3 %), and Haynesina sp. 1 (3 %).
Percentage data across the core show a range between 1.5 and 3 % for
species of this cluster with a maximum between 80 and 60 cm core depth.
Elphidium sp. 2 occurs widely from infralittoral to circalittoral environments but
also on leaves of phytal substrates (Sgarrella and Moncharmont Zei, 1993;
Langer, 1993).
Discussion
The analyses of both sedimentological and micropaleontological multi-proxy
data from core material collected off the coast of Thapsus allow (i) reconstruction of a scenario for the paleoenvironmental and morphodynamic
evolution for the past ∼ 4000 years (Fig. 12), (ii) an
assessment of the impact of natural and anthropogenic factors, and (iii) a
comparison to models developed for coastal wetlands, floodplains, and lake
environments from Tunisia and other Mediterranean coastal environments.
The base of core RD8 revealed carbonate sandstones (Fig. 13a) that are upper
Pleistocene in age (marine isotopic substage 5e, Jedoui et al., 1998). They
are commonly referred to the Tyrrhenian facies (Paskoff and Sanlaville,
1983) and can be correlated with carbonate sandstones outcropping along the
northern coast of Sfax (Khadraoui et al., 2019; Kamoun et al., 2020) and
Djerba Island (Jedoui et al., 1998). Following a glacial sea level lowstand,
coastal environments along Tunisia remained emerged. Marine deposits
indicating flooding were then recorded along the southern Skhira coast and
at the Hachichina wetlands dated to ∼ 7460
and ∼ 7890 cal yr BP, respectively (Zaibi et al., 2016; Ben
Khalifa et al., 2019). The lack of such deposits in the RD1, RD3, and RD8
core material suggests that the Thapsus area remained emerged even longer as
a result of neotectonic activity (from the upper Pleistocene to the
Northgrippian, Figs. 12, 13b). In fact, the Thapsus coast belongs to the
Sahel area characterized by major faults oriented in the NS, EW, NE–SW, and
NW–SE direction. Recent tectonic events have reactivated these structures,
resulting in a system of active faults such as the Skanes–Monastir fault.
Neotectonic activity resulted in extensive faulting, driven by a compressive
regime which continued from the Miocene to Quaternary (Bahrouni et al.,
2014).
Diagrammatic illustration showing the stratigraphy of Thapsus
subsurface sediments and dominant processes as inferred from
micropaleontological and sedimentological proxies.
Evidence for a delayed marine transgression at Thapsus is also provided by
the occurrence of marine sediments and biota. These sediments were
deposited directly above the erosional contact on the white carbonate
sandstones (Figs. 12, 13c) and indicate a rising sea level. The sediments
are herein dated to 4070 cal yr BP (RD8 core, UL1, 165 cm depth) and are
composed of fine sands that are rich in mollusk fragments, Posidonia seagrass debris,
Tyrrhenian lithoclasts, and benthic foraminifera, indicative of an open
marine, shallow nearshore habitat characterized by epiphytic forms that
dwell on phytal substrates. High-energy conditions are also indicated by the
dominance of gravelly, lithogenous, and clastic materials and by coarse (10 %), medium (20 %), and fine sand (30 %)
sediments of unit UL1 (core RD8).
Environmental evolution of the Thapsus coast and the Dzira Lagoon
as inferred from micropaleontological and sedimentological core data. For
each stage the dominant processes, the efficiency of the energy level and
the oceanic and anthropogenic influence on the development of the lagoon are
documented.
According to Jedoui et al. (1998), Morhange and Pirazzoli (2005), and
Paskoff and Sanlaville (1983), the Holocene marine transgression peaked at
around 3550–4050 cal BCE in southeastern Tunisia and in other parts of the
Mediterranean (Kayan, 1999; Kraft et al., 2007). The transgressive sediments
can be correlated with dated deposits from the northern Sfax coast (4500 cal yr BP; Khadraoui et al., 2018) and with material recorded from cores from the
Gulf of Gabes, where the maximum sea level influence was recorded at
around 4630 ± 160 yr BP (Morzadec-Kerfourn, 2002).
Origin of the Dzira Lagoon between 4070 and 2273 cal yr BP
A transition from an open nearshore setting towards a lagoonal environment
is indicated by the microfauna recovered from sediments deposited in the
lower part of unit Ul3 in core RD3. The foraminiferal assemblages in this
zone are characterized by a distinct increase in Ammonia aberdoveyensis (28 %), the
disappearance of typical marine taxa such as Quinqueloculina ungerina, Rotorbis auberii, Spiroloculina antillarum, and Peneroplis planatus, and a general
increase in total abundances (300 individuals per 1 g). The reduction of
marine taxa, the high percent abundances of Ammonia spp., and the rise of total
abundances suggest more restricted and possibly lagoonal conditions in which
nutrients accumulate (Carbonel, 1982). The formation of a lagoonal setting
is also marked in core RD8 (between units UL1 and UL2), where total
abundances and the number of stress-tolerant ammoniid taxa increase, while
shallow-water miliolids and epiphytes decrease. The transition from an open
marine setting (∼ 4070) towards a lagoonal environment (until
2273 cal yr BP) was probably favored by the presence of discontinuous
shoals (Oueslati, 1993) and the action of littoral drift currents, allowing
the genesis of a long sand spit (Fig. 13d). Similar conditions were recorded in
unit U1 of core RD1 (dated at 2079 yr BP), where brackish, shallow-water
taxa prevail together with other marine taxa. However, the mixture of
brackish water (Ammonia) and marine taxa suggests that the communication of the
Dzira Lagoon with the open sea, although now limited, continued to exist.
This finding is supported by archeological data from Younes (1999), who
reported increased silting during this time interval and noted that only
small boats were able to access the Roman harbor Portus Pristinus via a
tidal channel into the Dzira Lagoon. The formation of approximately
time-equivalent sand spits along the coast of Tunisia was also reported by
Khadraoui et al. (2018) from the northern Sfax coast, from Bin El Oudiane at
Djerba Island (Masmoudi et al., 2005), from the Hachichina wetlands (Ben
Khalifa et al., 2019), and from Rass Boutria at Acholla (Kamoun et al.,
2019, 2020). A progradation of coastal and lagoonal environments was also
reported from Boujmel by Lakhdar et al. (2006).
The second marine transgression between 2079 and 1280 cal yr BP
A second marine transgression between 2079 and 1280 cal yr BP is indicated
by faunal assemblages recorded in the upper part of unit Ul3 in core RD3.
This transgression is characterized by the dominance of smaller miliolid
foraminifera, the presence of symbiont-bearing peneroplids (Laevipeneroplis karreri, Peneroplis planatus), and the
highest species richness values recorded across the core (50 species). These
assemblages are commonly associated with seagrass meadows (leaves and
rhizome microhabitats) and other phytal substrates (algal thalli) (Langer,
1993; Langer et al., 2013; Mateu-Vicens et al., 2010). Sediments within this
unit show an increase in medium sand and a reduction of very fine sand, clay,
and silt. Both the foraminiferal biota and the grain size recorded suggest
that the semi-enclosed lagoonal habitat re-established connections with the
open sea (passages) to form an open lagoon environment between 2079 and 1280 cal yr BP (Fig. 13e). Findings of time-equivalent transgressions from the
nearby northern (1396 yr cal BP; Khadraoui et al., 2018) and southern
Sfax coast (1900 cal yr BP; Gargouri et al., 2007) support the hypothesis of
a second transgression during this time interval. In addition, archeological
studies conducted by Anzidei et al. (2011) on Punic and Roman materials from
along the coast of Tunisia showed that the local relative sea level
increased by 0.2 to 0.5 m over the last 2 kyr.
The formation of a semi-closed lagoon from 1280 cal yr BP
Depositional regime changes are again indicated by sediments deposited after
1280 cal yr BP. Foraminiferal faunal analysis of these deposits (unit Ul4 in
core RD3, in the upper part of UL3, and in UL4 of core RD8) show that both
the species richness and the number of individuals decrease. In addition,
the number of stress-tolerant ammoniid foraminifera increases, while miliolid
taxa decrease. Reduced species richness values, rising numbers of
stress-tolerant taxa, and decreasing H and E indices suggest a deterioration
of environmental conditions, possibly indicating a transition to
semi-enclosed lagoonal conditions. At the top of core RD3 and RD8, medium
and fine sand fractions increase substantially (90 %) and mark the
increasing closure of the lagoonal environment. Driving forces of the
environmental transformation include a steady accretion of sand deposits
favored by longshore sediment drift, ultimately resulting in an elongation of
the offshore sand spit.
Within unit U2 of core RD1, which is the core located just next to the present-day
and presumably old entrance channel, the foraminiferal fauna displays a
substantial rise of stress-tolerant indicator taxa (Ammonia spp. 30 %),
indicative of more restricted environmental conditions. Indeed,
archeological studies showed that the lagoonal environment during this time
interval was used as a harbor, where silting of the entrance channel
necessitated human interventions to keep the entrance channel open to the
sea (Carayon, 2008). Potential indications for dredging include abrupt
fluctuations in both the number of individuals per gram sediment and in the
number of species across this interval (50 and 4600 individuals per 2 g
sediment, 18 to 38 species). Because core data from neither RD3 nor RD8
indicate such abrupt changes in deposits, we hypothesize that
anthropogenic activities along the harbor entrance channel are plausible
sources explaining the abrupt changes. Towards the top of core RD1,
stress-tolerant species even increase to 45 %. Rising percent abundances
in RD1 indicate increasing constraints on the faunal exchange between
lagoonal and open-ocean waters and strongly suggest an environmental
transition towards present-day conditions with alternating periods of
opening and closing of the tidal channel, depending on the strength of tidal
currents and shift in littoral drift.
The recent construction of the modern port at the site of the ancient Roman
harbor reduced the natural coastal drift and resulted in the accumulation of
additional sandy beach sediments south of Rass Dimass, while silting
increased towards the north (between the mainland and the sand spit). It is
very likely that similar depositional process changes were triggered by
the construction of the extensive Roman breakwater mole and have thus been effective since antiquity (Slim et al., 2004).
Conclusion
Analyses of micropaleontological and sedimentological data were conducted on
three 14C-dated sediment cores to reconstruct the evolution of the
Thapsus coastline and the Dzira Lagoon (Tunisia) over the past 4000 years.
The proxy records provide evidence for sequences of transgressions that
shaped the coastal evolution, the trajectory of depositional facies, the
composition of foraminiferal faunal assemblages, and the formation of the
Dzira Lagoon. The transgressive events (∼ 4070 and
between 2079 and 1280 cal yr BP) are characterized by sandy sediments
deposited in a largely open marine lagoon environment and by diverse and
species-rich assemblages of shallow-water foraminifera. With rising sea
level at approximately 4070 cal yr BP, the shoreline moved to higher
grounds. The transgressive sediments overlay marine carbonate sandstones and
deposited facies of coarse-grained sands, lithoclasts, and Posidonia seagrass debris.
Between ∼ 4070 and 2273 cal yr BP, offshore bedrock relicts of
the Pleistocene shoreline became the focal point for sand accumulations and
initiated the formation of a discontinuous barrier, the elongation of the
sand spit, and the formation of an open lagoon environment. Foraminiferal
faunal assemblages from the newly formed lagoonal environment indicate a
reduced marine influence, as indicated by lower species richness values and
rising abundances of stress-tolerant taxa (Ammonia). A gradual transition from open
to more restricted lagoon conditions from 1280 cal yr BP until the present day is
indicated by increasing percent abundances of fine-grained sediments,
decreasing species richness values, and lower abundances of typical marine and
higher abundances of stress-tolerant taxa. The transition from an open
marine to a particularly shallow, semi-enclosed lagoon setting was favored
by the formation of an extensive sand spit and the Roman construction of an
extensive harbor breakwater mole.
Data availability
The data generated in this study are included within the paper and in Tables 1–2 and Figs. 3–11. Imaged specimens are deposited at the GEOGLOB laboratory, University of Sfax, Tunisia.
The supplement related to this article is available online at: https://doi.org/10.5194/jm-41-129-2022-supplement.
Author contributions
MK conceived this research project, processed and analyzed the samples, and performed light microscopy imaging. All authors contributed to fieldwork and sampling. Species identification and SEM imaging were performed by MK and MRL. MK and MRL prepared the paper and figures with contributions from all authors.
Competing interests
The contact author has declared that none of the authors has any competing interests.
Disclaimer
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Acknowledgements
The authors are grateful to Maria da Conceição Freitas and
the two anonymous reviewers for their constructive comments and criticism
that greatly improved the paper. We thank the editor-in-chief Francesca Sangiorgi and the editors Polina Shvedko and Laia Alegret for helpful
suggestions, advice, and editorial assistance.
Review statement
This paper was edited by Laia Alegret and reviewed by Maria Conceição Freitas and two anonymous referees.
References
Anzidei, M., Antonioli, F., Lambeck, K., Benini, A., Soussi, M., and
Lakhdar, R.: New insights on the relative sea level change during Holocene
along the coasts of Tunisia and western Libya from archaeological and
geomorphological markers, Quaternary Int., 232, 5–12, 2011.
Armynot du Châtelet, E., Francescangeli, F., and Frontalini, F.:
Definition of benthic foraminiferal bioprovinces in transitional
environments of the Eastern English Channel and the Southern North Sea, Rev.
Micropal., 61, 223-234, 2018.
Avnaim-Katav, S., Hyams-Kaphzan, O., Milker, Y., and Almogi-Labin, A.:
Bathymetric zonation of modern shelf benthic foraminifera in the Levantine
Basin, eastern Mediterranean Sea, J. Sea Res., 99, 97–106, 2015.
Bahrouni, N., Bouaziz, S., Soumaya, A., Ben Ayed, N., Attafi, K., Houla, Y.,
El Ghali, A., and Rebai, N.: Neotectonic and seismotectonic investigation of
seismically active regions in Tunisia: a multidisciplinary approach, J.
Seismol., 18, 235–256, 2014.
Ben Khalifa, K., Zaïbi, C., Bonnin, J., Carbonel, P., Zouari, K., Mnif,
T., and Kamoun, F.: Holocene environment changes in the Hachichina wetland
(Gulf of Gabes, Tunisia) evidenced by foraminifera and ostracods,
geochemical proxies and sedimentological analysis, Riv. Ital. Paleontol.
S., 125, 517–549, 2019.Bird, C., Schweizer, M., Roberts, A., Austin, W. E. N., Knudsen, K. L.,
Evans, K. M., Filipsson, H. L., Sayer, M. D. J., Geslin, E., and Darling, K.
F.: The genetic diversity, morphology, biogeography, and taxonomic
designations of Ammonia (Foraminifera) in the Northeast Atlantic, Mar. Micropaleontol.,
155, 101726, 10.1016/j.marmicro.2019.02.001, 2020.
Blanc-Vernet, L., Clairefond, P., and Orsolini, P.: Les foraminifères,
Géol. Médit., 6, 171–209, 1979.
Bouchet, P. and Rocroi, J. P.: Classification and nomenclator of gastropod
families, Int. J. Malacol., 47, 1–397, 2005.
Bouchet, P. and Rocroi, J. P.: Nomenclator of bivalve families with a
classification of bivalve families malacologia, Inst. of Malacol., 5,
21–184, 2010.Buosi, C., Armynot du Châtelet, E., and Cherchi, A.: Benthic
foraminiferal assemblages in the current-dominated Strait of Bonifacio
(Mediterranean Sea), J. Foramin. Res., 42, 39–55, 10.2113/gsjfr.42.1.39, 2012.
Calvo-Marcilese, L. and Langer, M. R.: Breaching biogeographic barriers: the
invasion of Haynesina germanica (Foraminifera, Protista) in the Bahia Blanca
estuary, Argentina, Biol. Invasions, 12, 3299–3306, 2010.Calvo-Marcilese, L. and Langer, M. R.: Ontogenetic Morphogenesis and
Biogeographic Patterns: Resolving Taxonomic Incongruences within “Species”
of Buccella from South American Coastal Waters, Rev. Bras. Paleontol., 15, 23–32,
10.4072/rbp.2012.1.02, 2012.
Carayon, N.: Les ports pheniciens et punique géomorpologie et
infrastructure, PhD thesis, Université Strasbourg, 1384 pp., 2008.
Carbonel, P.: Les Ostracodes, traceurs des variations hydrologiques dans les
systèmes de transition eau douce eau salée, Mem. Soc. Geol. Fr.,
144, 117–128, 1982.
Cimerman, F. and Langer, M. R.: Mediterranean Foraminifera,
Slovenska Akademija Znanosti, Ljubljana, 118 pp., 1991.
Dallas, M. F. and Yorke, R. A.: Underwater surveys of North Africa, Jugoslavia and Italy, Underwater Association Report, 21–34, 1968.
Davidson, D. P. and Yorke, R. A.: The Enigma of the Great Thapsus Harbour
Mole, Int. J. Naut. Archaeol., 43, 35–40, 2014.
Délibrias, G.: Le carbone 14, in: Méthodes de datation par les phénomènes nucléaires naturels: applications, edited by: Roth, E. and Poty, B., Collection CEA, Éditions Masson,
Paris, 421–458, 1985.Dimiza, M. D., Koukousioura, O., Triantaphyllou, M. V., and Dermitzakis, M.
D.: Live and dead benthic foraminiferal assemblages from coastal
environments of the Aegean Sea (Greece): distribution and diversity, Rev.
Micropal., 59, 19–32, 10.1016/j.revmic.2015.10.002, 2016.
Frezza, V. and Carboni, M. G.: Distribution of recent foraminiferal
assemblages near the Ombrone River mouth (Northern Tyrrhenian Sea, Italy),
Rev. Micropal., 52, 43–66, 2009.
García-Sanz, I., Usera, J., Guillem, J., Giner-Baixauli, A., and
Alberola, C.: Geographical and bathymetric distribution of foraminiferal
assemblages from the Alboran Sea (western Mediterranean), Quaternary
Int., 481, 146–156, 2018.
Gargouri-Ben Ayed, Z., Souissi, R., Soussi, M., Abdeljaouad, S., and Zouari,
K.: Sedimentary Dynamics and Ecological State of Nakta Tidal Flat
(Littoral), South of Sfax, Gulf of Gabés, Tunisia, Chin. J. Geochem.,
26, 244–251, 2007.Giocondo, G. and Palladio, A.: Battle of Thapsus, https://commons.wikimedia.org/wiki/File:Battle_of_Thapsus.jpg (last access: 26 August 2022), 1567.
Hammer, Ø., Harper, D. A., and Ryan, P. D.: PAST: Paleontological
statistics software package for education and data analysis, Palaeontol.
Electr., 4, 9 pp., 2001.Heaton, T., Köhler, P., Butzin, M., Bard, E., Reimer, R. W., Austin, W.
E. N., Ramsey, C. B., Grootes, P. M., Hughen, K. A., Kromer, B., Reimer, P.
J., Adkins, J., Burke, A., Cook, M. S., Olsen, J., and Skinner, L. C.: Marine20 - The
Marine Radiocarbon Age Calibration Curve (0–55,000 cal BP), Radiocarbon,
62, 779–820, 10.1017/RDC.2020.68, 2020.
Hunt, C. O., Farrell, M., Fenech, K., French, C., McLaughlin, R., Blaauw,
M., Bennett, J., Flood, R., Pyne-O'Donnell, S., Reimer, P. J.,
Ruffell, A., Cresswell, A. J., Kinnaird, T. C., Sanderson, D., Taylor, S.,
Malone, C., Stoddart, S., and Vellan, N. C.: Chronology and stratigraphy of the valley
systems. Temple landscapes fragility, change and resilience of Holocene environments in the Maltese Islands, Mc Donald Institute for Archaeological Research, Cambridge, UK, Vol. 1, 35–71, 2020.
Haunold, T. G., Baal, C., and Piller, W. E.: Benthic foraminiferal associations
in the Northern Bay of Safaga, Red Sea, Egypt, Mar. Micropaleontol., 29, 185–210,
1997.
Hayward, B. W., Grenfell, H. R., Reid, C. M., and Hayward, M. R.: Recent New
Zealand shallow-water benthic foraminifera: taxonomy, ecologic distribution,
biogeography, and use in paleoenvironmental assessment, Institute of
Geological & Nuclear Sciences monograph 21, New Zealand Geol. Surv.
Paleont. Bull., 21, 1–258, 1999.
Hayward, B. W., Holzmann, M., Pawlowski, J., Parker, J. H., Kaushik, T., and
Toyofuku, M. S.: Tsuchiya: Molecular and morphological taxonomy of living
Ammonia and related taxa (Foraminifera) and their biogeography, Micropaleontology,
67, 109–313, 2021.
Jedoui, Y., Kallel, N., Fontugne, M., Ben Ismail, M. H., M'Rabet, A., and
Montacer, M.: A high relative sea level stand in the middle Holocene of
Southeastern Tunisia, Mar. Geol., 147, 123–130, 1998.
Kaminski, M. A., Aksu, A., Box, M., Hiscott, R. N., Filipescu, S., and
Al-Salameen, M.: Late Glacial to Holocene benthic foraminifera in the
Marmara Sea: implications for Black Sea–Mediterranean Sea connections
following the last deglaciation, Mar. Geol., 190, 165–202, 2002.
Kamoun, M., Khadraoui, A., Ben Hamad, A., Zaïbi, C., Langer, M. R.,
Bahrouni, N., Ben Youssef, M., and Kamoun, F.: Impact of relative sea level
change and sedimentary dynamic on an historic site expansion along the coast
between Sfax and Jebeniena, Conference of the Arabian Journal Geosciences
(CAJG), 12–15 November 2018, Hammamet, Tunisia, 141–143, 2019.Kamoun, M., Zaïbi, C., Langer, M. R., Khadraoui, A., Ben Hamad, A., Ben
Khalifa, K., Carbonel, P., and Ben Youssef, M.: Environmental evolution of
the Acholla coast (Gulf of Gabes, Tunisia) during the past 2000 years as
inferred from paleontological and sedimentological proxies, Neues Jahrb. Geol. Pal., 296, 217–235, 10.1127/njgpa/2020/0897,
2020.
Kayan, I.: Holocene stratigraphy and geomorphological evolution of the
Aegean coastal plains of Anatolia, Quaternary Sci. Rev., 18, 541–548, 1999.Khadraoui, A., Kamoun, M., Ben Hamad, A., Zaïbi, C., Bonnin, J.,
Viehberg, F., Bahrouni, N., Sghari, A., Abida, H., and Kamoun, F.: New
insights from microfauna associations characterizing palaeoenvironments, sea
level fluctuations and a tsunami event along Sfax Northern coast (Gulf of
Gabes, Tunisia) during the Late Pleistocene-Holocene, J. Afr. Earth Sci.,
147, 411–429, 10.1016/j.jafrearsci.2018.05.011,
2018.
Khadraoui, A., Zaïbi, C., Carbonel, P., Bonnin, J., and Kamoun, F.:
Ostracods and mollusks in northern Sfax coast: reconstruction of Holocene
paleoenvironmental changes and associated forcing, Geo-Mar. Lett., 39, 313–336, 2019.Kraft, J. C., Bückner, H., Kayan, I., and Engelmann, H.: The geographies of
ancient Ephesus and the Artemision in Anatolia, Geoarchaeology, 22, 121–149,
10.1002/gea.20151, 2007.
Lakhdar, R., Soussi, M., Ben Ismail, M. H., and M'Rabet, A.: A Mediterranean
Holocene restricted coastal lagoon under arid climate: case of the
sedimentary record of Sabkha Boujmel (SE Tunisia), Palaeogr. Palaeocl., 241, 177–191, 2006.
Langer, M. R.: Recent epiphytic foraminifera from Vulcano (Mediterranean
Sea), Rev. Paléobiol., 2, 827–832, 1988.
Langer, M. R.: Distribution, Diversity and Functional Morphology of Benthic
Foraminifera from Vulcano (Mediterranean Sea), PhD thesis, University of
Basel, 159 pp., 1989.Langer, M. R.: Epiphytic foraminifera, Mar. Micropal., 20, 235–265,
10.1016/0377-8398(93)90035-V, 1993.
Langer, M. R. and Schmidt-Sinns, J.: The 100 most common Foraminifera from
the Bay of Fetovaia, Elba Island (Mediterranean Sea), Monographie im
Selbstverlag, Institut für Paläontologie, Universität Bonn, 1–15,
2006.
Langer, M. R., Hottinger, L., and Huber, B.: Functional morphology in
low-diverse benthic foraminiferal assemblages from tidal-flats of the North
Sea, Senck. Marit, 20, 81–99, 1990.
Langer, M. R., Frick, H., and Silk, M. T.: Photophile and sciaphile
foraminiferal assemblages from marine plant communities of Lavezzi Islands
(Corsica, Mediterranean Sea), Rev. Paléobio., 17, 525–530, 1998.Langer, M. R., Thissen, J. M., Makled, W. A., and Weinmann, A. E.: The
foraminifera from the Bazaruto Archipelago (Mozambique), Neues Jahrb. Geol. Pal., 297, 155–170, 10.1016/j.revmic.2009.11.001,
2013.
Masmoudi, S., Yaich, C., and Ammoun, M.: Evolution et morphodynamique des
iles barrières et des flèches littorales associées à des
embouchures microtidales dans le Sud-Est tunisien, Bull. l'Inst. Sci.,
Section Sciences de la Terre, 27, 65–81, 2005.Mateu-Vicens, G., Box, A., Deudero, S., and Rodríguez, B.: Comparative
analysis of epiphytic foraminifera in sediments colonized by
seagrass Posidonia oceanica and invasive macroalgae Caulerpa spp., J. Foramin. Res., 40, 134–147, 2010.
Morhange, C. and Pirazzoli, P. A.: Mid-Holocene emergence of southern
Tunisian coasts, Mar. Geol., 220, 205–213, 2005.
Morigi, C., Jorissen, F. J., Fraticelli, S., Horton, B. P., Principi, M.,
Sabbatini, A., and Negri, A.: Benthic foraminiferal evidence for the
formation of the Holocene mud-belt and bathymetrical evolution in the
central Adriatic Sea, Mar. Micropaleontol., 57, 25–49, 2005.
Morzadec-Kerfourn, M. T.: L'évolution des Sebkhas du Golfe de Gabès
(Tunisie) à la transition Pléistocène supérieur –
Holocène, Quaternaire, 13, 111–123, 2002.Murray, J.: Ecology and applications of benthic foraminifera, Cambridge
University Press, 426 pp., 10.1017/CBO9780511535529, 2006.Oflaz, S. A.: Taxonomy and distribution of the benthic foraminifera in the
Gulf of Iskenderun, Eastern Mediterranean, MSc thesis, Middle East Technical
University, http://etd.lib.metu.edu.tr/upload/3/12607725/index.pdf (last access: 26 August 2022), 2006.
Oueslati, A.: Les côtes de la Tunisie: géomorphologie et environnement
et aptitudes à l'aménagement,
Publications de l'Université de Tunis, Faculté des Lettres et Sciences Humaines, 34, 387 pp., 1993.
Paskoff, R. and Sanlaville, P.: Les côtes de la Tunisie. Variations du niveau marin depuis le Tyrrhénien, 14, 1, Persée-Portail des revues scientifiques en SHS, 1983.Pielou, E. C.: The measurement of diversity in different types of biological
collections, J. Theor. Biol., 13, 131–144, 1966.
Saad, S. A. and Wade, C. M.: Biogeographic distribution and habitat
association of Ammonia genetic variants around the coastline of Great Britain, Mar.
Micropaleontol., 124, 54–62, 2016.
Sgarrella, F. and Moncharmont Zei, M.: Benthic foraminifera of the Gulf of
Naples (Italy): systematics and autoecology, Boll. Soc. Paleontol. I.,
32, 145–264, 1993.
Siani, G., Paterne, M., Arnold, M., Bard, E., Metivier, B., Tisnerat, N., and
Bassinot, F.: Radiocarbon reservoir ages in the Mediterranean Sea and Black
Sea, Radiocarbon, 42, 271–280, 2000.
Slim, P., Trousset, P., Paskoff, R., and Oueslati, A.: Le littoral de la
Tunisie, Et. Géoarch. Hist., CNRS, 185–187, 2004.
Souissi, R., Turki, I., and Souissi, F.: Effect of submarine morphology and
environment quality: Case of Monastir Bay (Eastern Tunisia), Carpath. J.
Earth Env., 9, 231–239, 2014.Vita-Finzi, C. and Roberts, N.: Selective leaching of shells for 14C dating,
Radiocarbon, 26, 54–58, 1984.
Yorke, R. A.: Les ports engloutis de Tripolitaine et de Tunisie,
Archeologia, 17, 18–24, 1967.
Younes, A.: L'installation portuaire à Thapsus: mise au point à
partir des textes anciens et de la documentation archéologique, La
Méditerranée: l'Homme et la mer, Actes du premier séminaire,
Mahdia décembre 1998, CERES, Tunis, 21, 181–193, 1999.
Zaïbi, C., Kamoun, F., Viehberg, F., Carbonel, P., Jedoui, Y., Abida,
A., and Fontugny, M.: Impact of relative sea level and extreme climate events
on the Southern Skhira coastline (Gulf of Gabes, Tunisia) during Holocene
times: Ostracodes and foraminifera associations response, J. Afr. Earth
Sci., 118, 120–136, 2016.