Surface distributions of salt-marsh foraminifera from Connecticut

www.elsevier.com/locate/marmicro

gy 51 (2004) 1–21
Marine Micropaleontolo
Surface distributions of salt-marsh foraminifera from Connecticut,

USA: modern analogues for high-resolution sea level studies

R.J. Edwards*, A.J. Wright, O. van de Plassche

Department of Earth and Life Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands

Received 25 January 2002; received in revised form 1 August 2003; accepted 11 August 2003

Abstract

Salt-marsh foraminifera are routinely used as sea-level indicators since their vertical distribution is closely linked with

elevation relative to the tidal frame. The precise nature of these relationships is variable in time and space, and the accuracy of

sea-level reconstructions depends upon the selection of appropriate modern analogues that reliably reflect past fauna–

environment associations. The marshes of Connecticut, USA, are sites of ongoing research seeking to produce high-resolution

records of sea-level change, yet, little published data regarding their modern foraminiferal distributions exist. This paper

presents new surface foraminiferal data from three Connecticut salt-marshes and evaluates their suitability as modern analogues

for past sea-level changes. The results indicate that significant intra- and inter-site variability between these marshes and those

of neighbouring states exists. As a consequence of this, the extrapolation of fauna–environment relationships developed from

marshes with different hydrographic, physiographic, vegetative or climatic characteristics may produce erroneous

reconstructions, even when adjusted for variations in tidal range. These errors are potentially greatest if single ‘indicator’

species are used since the relative abundance of individual taxa does not vary consistently with elevation, even in high marsh

environments from the same site. Whilst cluster analysis demonstrates that foraminiferal assemblages from Connecticut are

vertically zoned with respect to mean high water (MHW), the composition, elevation and height range of these zones is variable

between sites. This spatial heterogeneity results in reconstructions of relatively low and variable precision that restricts their

utility in high-resolution sea-level research. New studies seeking to distil decimetre-scale changes in relative sea level will need

to employ quantitative methods capable of combining multi-site information to develop fauna–environment relationships that

capture this spatial variability. Reconstructions will be most precise when employing local foraminiferal distributions, but may

require the collection of additional modern analogue samples from other regions when the extant foraminiferal population of a

site differs in composition from its sub-fossil counterpart.

D 2003 Elsevier B.V. All rights reserved.

Keywords: foraminifera; sea-level changes; salt-marsh; holocene; connecticut

0377-8398/$ - see front matter D 2003 Elsevier B.V. All rights reserved.

doi:10.1016/j.marmicro.2003.08.002

* Corresponding author. Current address: Departments of

Geography and Geology, Trinity College Dublin, Dublin 2, Ireland.

Fax: +353-1-671-3397.

E-mail address: [email protected] (R.J. Edwards).

1. Introduction

The use of salt-marsh foraminifera as precise

indicators of relative sea-level change has attracted

considerable attention since the pioneering work of

R.J. Edwards et al. / Marine Micropaleontology 51 (2004) 1–212

Scott and Medioli (1978, 1980a). The potential to

relocate former relative sea levels to within F 5 cm

provides an opportunity to investigate relatively

small magnitude (decimetre scale) variations that

are central to research seeking to quantify the

relationships between ocean and climate. However,

this degree of precision is not associated with all

foraminifera species or assemblages. Instead it

relates to a mono-specific assemblage of Jadammina

macrescens, referred to as faunal zone 1A by Scott

and Medioli (1978), which is restricted to the

marsh–upland transition, close to the upper limit

of marine influence. Whilst other assemblages of

foraminifera also exhibit vertical zonation, their

composition and elevation ranges may vary consid-

erably within and between sites, reflecting local

differences in environmental variables such as sa-

linity and climate (Scott and Medioli, 1980a; Scott

and Leckie, 1990; Gehrels, 1994; De Rijk, 1995b).

For this reason, an essential component of any

investigation seeking to produce high-resolution

sea-level reconstructions is the precise and accurate

determination of modern species–environment rela-

tionships that are representative of the study area

(Scott and Medioli, 1986).

In this paper, we present new contemporary salt-

marsh foraminiferal data from three study areas in

Connecticut, USA (Fig. 1). This region is a locus

for high-resolution sea-level research seeking to

elucidate the relationship between climate and sea

level change during the late Holocene (van de

Plassche, 1991, 2000; Thomas and Varekamp,

1991; Varekamp et al., 1992; Nydick et al., 1995;

van de Plassche et al., 1998). Despite this compar-

atively long history of research, relatively little has

been published regarding the modern distribution of

salt-marsh foraminifera in Connecticut, and their

relationships with tide levels remain poorly quanti-

fied (Gehrels and van de Plassche, 1999). These

data are particularly important given the apparent

absence of assemblages comparable to faunal zone

1A, reported in other New England marshes (Scott

and Leckie, 1990; De Rijk and Troelstra, 1997;

Gehrels and van de Plassche, 1999). This paper

therefore examines the extent to which high marsh

foraminiferal assemblages in Connecticut exhibit

evidence of vertical zonation; the spatial coherence

of these zones in terms of composition and eleva-

tion; and the implications that these results have for

studies seeking to produce precise (decimetre scale)

sea-level reconstructions from the salt-marshes of

Connecticut.

2. Materials and methods

2.1. Sampling methodology

The sampling requirements of surface foraminif-

eral investigations conducted to complement palae-

oenvironmental analysis differ markedly from those

seeking to analyse the taphonomic and ecological

attributes of the foraminifera themselves (De Rijk,

1995a). Since the goal of foraminifera-based sea-

level research is the reconstruction of former tide

levels, modern samples were collected along trans-

ects encompassing a range of altitudes and vegeta-

tion zones most analogous to the environments

encountered in fossil cores. Sampling was concen-

trated in the vegetated marsh above mean high

water (MHW), since this is the principal environ-

ment analysed in sea-level studies (Gehrels and van

de Plassche, 1999). Disturbed areas such as pond

holes, creek margins and low marsh sediments

bioturbated by fiddler crabs were not sampled since

boreholes containing these deposits are not consid-

ered reliable indicators of sea-level change. The

majority of salt-marshes in Connecticut have been

ditched (Dreyer and Niering, 1995), and this human

interference has altered their hydrological regime

(Van der Molen, 1997). Where possible, surface

transects were situated away from these ditches

and in areas displaying a well-developed floral

zonation, since these are considered to be more

representative of their ‘natural’, pre-engineered

state.

Surface foraminiferal samples were collected in

vertical intervals of 5F 1 cm and their altitude

determined by levelling to the nearest geodetic

datum (NGVD 29). Live specimens were stained in

the field using Rose Bengal and stored in ethanol.

On return to the laboratory, samples were washed

through 500- and 63-Am mesh sieves after the

methods described by Scott and Medioli (1980a).

Samples were suspended in approximately 500 ml of

water and sub-divided into eight aliquots using a

Fig. 1. Site map showing the location of the surface foraminiferal transects and temporary tide gauges.

R.J. Edwards et al. / Marine Micropaleontology 51 (2004) 1–21 3


rotary wetsplitter following the study by De Rijk

(1995a) which found this to be the most accurate and

time efficient preparation method. All samples were

examined wet under a binocular microscope and

generally over 200–300 tests were counted where

possible (Appendix B). In common with other stud-

ies, some of the highest marsh samples are associat-

ed with smaller counts reflecting low species

abundance and diversity at the upper limit of marine

influence. These assemblages are dominated by only

one or two species and are reliably represented by

low counts. The use of life, death or total forami-

niferal assemblages remains a matter of contention

(Scott and Medioli, 1980b; Murray, 1991, 2000;

Horton, 1997; Murray and Bowser, 2000). Here,

dead populations are used to facilitate later compar-

ison with fossil assemblages in accordance with

Horton et al. (1999). It should be noted that dead

individuals contribute at least 90% of the total

number of tests counted at each site.

2.2. Taxonomy

Salt-marsh foraminiferal assemblages are typical-

ly dominated by less than 10 benthic species,

reflecting the marginal-marine nature of inter-tidal

environments. A taxonomic list and plates of the

key salt-marsh taxa recovered in our surveys are

presented in Appendix A. The pioneering forami-

nifera-based investigations of Thomas and Vare-

kamp (1991) and Varekamp et al. (1992), which

underpin many of the subsequent sea-level studies

in Connecticut, use a modified version of the

Nova Scotia vertical zonation, and their taxonomy

follows that of Scott and Medioli (1980a). In this

paper, we follow the taxonomy of De Rijk (1995a),

which differs from that of Scott and Medioli

(1980a) by its separation of individuals formerly

grouped as Trochammina macrescens, into the sep-

arate species Balticammina pseudomacrescens and

J. macrescens. Gehrels and van de Plassche (1999)

demonstrate that B. pseudomacrescens and J.

macrescens exhibit different relationships with ele-

vation relative to MHW and that their separation

increases the amount of sea-level information that

may be extracted from fossil foraminiferal assemb-

lages in Maine. The modern distribution of B.

pseudomacrescens in the salt-marshes of Connecti-

cut is poorly understood and one aim of this

study is to address this fundamental lack of know-

ledge. Similarly, we follow De Rijk (1995a) by

differentiating between Trochammina inflata and

Siphotrochammina lobata, the latter of which is

similar to the microspheric form of Tr. inflata

described by Scott and Medioli (1980a). This

distinction is made to explore whether these forms

display different distributions in Connecticut, and

hence contain additional environmental information.

Ultimately, the taxonomic issues surrounding the

differentiation of genus, species or ecophenotype

do not influence the use of foraminifera as modern

analogues, providing these ‘species’ or forms are

identified consistently.

2.3. Infaunal foraminifera

Sea-level reconstructions based on modern sur-

face distributions of foraminifera implicitly assume

that infaunal populations do not constitute a signif-

icant proportion of the total assemblages recovered.

A number of studies have questioned the reliability

of this assumption, reporting the occurrence of

living foraminifera at depths of 30 cm or more in

salt-marshes from Georgia and British Columbia

(Goldstein and Watkins, 1999; Ozarko et al.,

1997). These salt-marsh environments are quite

different from those encountered in New England,

however, where a study by Saffert and Thomas

(1998) indicates that infaunal activity is less signif-

icant, particularly in high marsh sediments com-

posed of dense, intertwined root masses and marsh

grasses. At Kelsey marsh in Connecticut, near the

Hammock River transect presented here, Saffert and

Thomas (1998) report that whilst living foraminifera

may be found up to a depth of 30 cm, 90% of the

living individuals occur above 20 cm. More impor-

tantly, in the high marsh environments, such as

those considered in this study, species maxima

occur between 0 and 2.5 cm depth, and only 5%

of the total population below 5 cm is living.

To test this result, a 30-cm core was collected

from the high marsh environment adjacent to our

surface transects at Double Beach marsh. The sed-

iment was sliced into 1-cm-thick slices and the

material processed in the same way as the surface

samples. The results are summarised in Fig. 2, and

Fig. 2. Summary foraminiferal diagram from a 30-cm short core collected in the high marsh at Double Beach. The relative abundance of species

in the death assemblage is show in black. The occurrence of living infaunal foraminifera is shown in grey, expressed as a percentage of the total

count (live + dead).

Table 1

Summary tidal characteristics for the study area derived from

permanent NOAA tide gauges and temporary tide gauges installed

at Double Beach and Pattagansett River marshes

Location Altitude (m NGVD)

MHHW MHW MTL MLLW

Bridgeport 1.34 1.24 0.21 � 0.89

New Haven 1.24 1.14 0.19 � 0.83

Double Beach 1.15 1.09 0.19 –

Hammock River 0.98 0.84 0.16 –

Pattagansett 0.76 0.61 0.14 –

New London 0.61 0.52 0.13 � 0.33


confirm the pattern identified by Saffert and Thom-

as (1998). Stained tests contribute 27% of the

topmost sample (0–1 cm depth) and fall rapidly

with increasing depth. The life component contrib-

utes less than 10% of the assemblage at 2–3 cm

depth, and falls to between 2% and 3% below this.

2.4. Assemblage groups and tide levels

The seminal paper by Scott and Medioli (1980a)

visually grouped contemporary salt-marsh foraminif-

era to define vertical zonations at a number of sites.

More recent work has sought to group assemblages

on statistical grounds which may then be related to

distinct depositional environments (e.g., Patterson,

1990; Jennings and Nelson, 1992; De Rijk, 1995a).

Here, assemblage zones are based on the results of

unconstrained incremental sum of squares cluster

analysis. Data are screened to remove species con-


tributing under 2% of any sample, and counts of

less than 40 specimens (Horton et al., 1999), and

analysed via the program Tilia, release 2.0 b.0.5

(Grimm, 1991–1993).

The altitude of foraminiferal assemblage zones

relative to NGVD is of less significance in sea-level

reconstruction than their elevation relative to the tidal

frame. The assemblage zones identified via cluster

Fig. 3. Summary foraminiferal diagrams showing the relative abundances

Beach marsh: (a) transect 1; (b) transect 2. Samples are plotted against a

proportion of live specimens expressed as a percentage of the total count

analysis are therefore plotted relative to MHW at each

site, since this variable is commonly reconstructed in

sea-level investigations (e.g., van de Plassche, 2000).

Long-term tidal data from permanent tide gauges at

New London, New Haven and Bridgeport are used in

conjunction with shorter-term (up to 6 months) records

from temporary tide gauges installed at Double Beach

and Pattagansett marshes (Table 1).

of individual species comprising the death assemblages at Double

ltitude (NGVD). The number of dead specimens counted, and the

(live + dead) are also shown.


3. Study sites

Surface foraminiferal samples were taken from

three Connecticut salt-marshes at Double Beach,

Hammock River and Pattagansett River (Fig. 1).

These marshes are, or are close to, locations of sea-

level research, and surface sampling was undertaken

to complement these stratigraphic investigations. The

mean tidal range in the area increases westward from

c. 0.8 m near Pattagansett River to c. 1.9 m near

Double Beach (NOAA tide tables). Tidal character-

istics for each site are given in Table 1.

All the study sites possess the three main vegeta-

tion zones characteristic of Connecticut salt-marshes:

low marsh, high marsh and marsh–upland border

(Redfield, 1972; Dreyer and Niering, 1995). The

dominant vegetation type at each sampling location

is noted in Appendix B. The low marsh zone, which

develops on inter-tidal flats and almost extends up to

MHW, is only represented in the lowermost samples

from Pattagansett River, reflecting the fact that sam-

pling was concentrated in the high marsh zone

(Section 2.1). At the other sites, transects commence

around MHW and are dominated by high marsh

plants like Spartina patens and Spartina alterniflora

(stunted). The high marsh to upland transition varies

Fig. 4. Summary foraminiferal diagrams showing the relative abundances o

River marsh. Samples are plotted against altitude (NGVD). The number

expressed as a percentage of the total count (live + dead) are also shown.

between sites, primarily reflecting local salinity con-

ditions and the degree of human modification at the

back of the marshes. At Double Beach, the upper

salt-marsh is backed by scrub and Iva frutescens

(transect 1) or grades through Scirpus robustus into

fringing woodland (transect 2). The presence of

sedges and reeds such as Sc. robustus and Phrag-

mites australis are indicative of brackish conditions

where freshwater inputs moderate the marine influ-

ence. At Hammock River, the rear of the marsh is

embanked and planted with a line of trees. The

transition from the upper marsh to the bare soil at

the foot of the embankment is associated with a

dense stand of Ph. australis. At Pattangansett River,

the upland transition is associated with I. frutescens,

and in transect 2, patches of dry, sandy soil flanking

a car park.

4. Results

Highmarsh foraminiferal distributions were collect-

ed from a total of five surface transects in three study

areas. These data are used to investigate both intra-and

inter-site variability in modern assemblages and their

distributions. Full counts are tabulated in Appendix B.

f individual species comprising the death assemblages at Hammock

of dead specimens counted and the proportion of live specimens

Micropaleontology 51 (2004) 1–21

4.1. Double Beach marsh

Two transects comprising a total of 20 samples

were collected at Double Beach marsh (Fig. 3a–b;

Table B1). The results from both transects are

broadly comparable in terms of the species present.

All of the samples are dominated by the agglutinat-

ed species J. macrescens, and this reflects the fact

that sampling was focussed in the high marsh

R.J. Edwards et al. / Marine8

Fig. 5. Summary foraminiferal diagrams showing the relative abundances o

River marsh: (a) transect 1; (b) transect 2. Samples are plotted against a

proportion of live specimens expressed as a percentage of the total count

environment. Whilst the upper portion of transect

1 failed to capture faunal zone 1A of Scott and

Medioli (1980a), it was represented in the top two

samples of transect 2.

A range of other agglutinated species provide

lesser contributions to the total high marsh assem-

blage. Most notable among these are Tr. inflata and

Si. lobata, which exhibit very similar patterns of

distribution. Previous studies in Connecticut have

f individual species comprising the death assemblages at Pattagansett

ltitude (NGVD). The number of dead specimens counted, and the

(live + dead) are also shown.


not reported Si. lobata, perhaps grouping it with Tr.

inflata, to which it may be related (see Section

2.2).

The slightly greater vertical range of transect 1

(0.49 m) relative to transect 2 (0.35 m) accounts for

the greater diversity of species present in the former.

In particular, species that are reported from middle to

lower marsh environments in neighbouring New

England marshes, such as Arenoparrella mexicana

and Ammotium salsum, are found in the lower

samples.

4.2. Hammock River marsh

A single surface foraminiferal transect comprising

14 samples was collected at Hammock River marsh

(Fig. 4; Table B2). The occurrence and distribution of

key species is similar to that reported for Double Beach

marsh, with J. macrescens dominant (52% total tests

counted), and lesser contributions provided by Tr.

inflata (13%), Si. lobata (7%), Tiphotrocha compri-

mata (7%) and Haplophragmoides manilaensis (6%).

The topmost samples show a mixed assemblage of J.

macrescens, H. manilaensis, and Miliammina fusca

similar to that recorded at the top of Double Beach

transect 2.

The slightly greater vertical range sampled at

Hammock River (0.59 m) reveals a clearer succession

of foraminiferal species. Whilst the abundance of J.

macrescens remains high throughout, there is a clear

interchange between declining abundances of M.

fusca and the arrival of Tr. inflata, Si. lobata, and

Ti. comprimata.

4.3. Pattagansett River marsh

Two transects comprising a total of 26 samples

were collected at Pattagansett River marsh (Fig. 5a–

b; Table B3). The results from both transects are

similar, with the larger vertical range of transect 1

(0.7 m) capturing slightly more of the succession

than transect 2. The topmost samples of transect 1

show a virtually monospecific assemblage of J.

macrescens, comparable to faunal zone 1A, whilst

similar altitudes sampled in transect 2 were devoid

of foraminifera.

The distribution of other principal species (Tr.

inflata, Si. lobata, Ti. comprimata and M. fusca)

show remarkable consistency between transects,

both in terms of the sequence of change and the

altitudes at which these changes occur. The most

obvious interchange once again is between the M.

fusca and Tr. inflata/Si. lobata assemblages. In

contrast to Hammock River marsh, however, M.

fusca abundances increase with decreasing altitude.

The lowermost samples from transect 1 record an

increase in the diversity of agglutinated species

associated with lower marsh conditions, including

Ammot. salsum, Areno. mexicana and Ammobacu-

lites dilatatus.

5. Discussion

The composition of the high marsh death assemb-

lages presented here is broadly comparable to those

of other New England marshes. J. macrescens

dominates all of the assemblages reflecting the fact

that few samples were collected from below MHW.

Tr. inflata is also common throughout the high

marsh zone and its distribution is closely associated

with Si. lobata. This is consistent with the view of

Scott and Medioli (1980a) that Si. lobata is a

microspheric form of Tr. inflata, and suggests that,

in the high marsh zone at least, little additional

environmental information is obtained by sub-divid-

ing these forms.

Only small numbers of B. pseudomacrescens are

recorded in the surveys (rarely contributing more

than 1% of the total assemblage). This apparent

rarity is in stark contrast with distributions reported

from Maine, where B. pseudomacrescens can con-

tribute up to 80% of the assemblage (Gehrels and

van de Plassche, 1999). Further work is necessary to

determine the reasons for these differences in abun-

dance, especially given the proximity and apparent

similarity of the settings. This is of particular impor-

tance since fossil assemblages containing large pro-

portions of B. pseudomacrescens are found within

the marsh sediments of Connecticut (Gehrels and

van de Plassche, 1999).

The lowest elevation samples are characterised

by the presence of Areno. mexicana and low

abundances of other agglutinated taxa such as

Ammobaculites or Reophax species. Consequently,

whilst the calcareous component of the life assem-


blage is not retained in the death assemblage due to

post-mortem dissolution, agglutinated assemblages

can still be used to distinguish high and low marsh

environments.

The surface distributions of H. manilaenis, M.

fusca and Ti. comprimata exhibit greater spatial

variability reflecting the influence of other environ-

mental variables (e.g., salinity, substrate). The

results from other salt-marsh studies indicate that

the distribution of H. manilaensis is controlled by

local salinity conditions, with it favouring brackish

environments at the rear of marshes or lower

elevation areas associated with freshwater seeps

(Parker and Athearn, 1959; Scott and Medioli,

1980a; Scott and Leckie, 1990; De Rijk, 1995b).

The most notable H. manilaensis dominated assem-

blage (up to 30%) is recorded at the top of transect

1 from Double Beach and is similar to the low

salinity ‘marsh fringe’ assemblage reported from

Massachusetts by De Rijk (1995b). The absence of

H. manilaensis from the upper samples in transect 2

illustrates the localised influence that freshwater

drainage can exert on the composition of high

marsh foraminiferal assemblages.

The distribution of Ti. comprimata appears to

vary between sites. In Massachusetts, De Rijk and

Troelstra (1997) suggest that it is indicative of

environments above MHW where salinity remains

high. Conversely, Scott and Leckie (1990) state that

it is a good indicator of the transition from low to

high marsh since its abundance decreases markedly

above MHW. In the neighbouring marshes of

Maine, Gehrels (1994) notes peaks in relative abun-

dance of Ti. comprimata between MHW and mean

higher high water (MHHW). The results from Con-

necticut are consistent with the interpretations of De

Rijk and Troelstra (1997) and Gehrels (1994),

suggesting Ti. comprimata is indicative of environ-

ments at or above MHW. Transect 1 from Patta-

ganssett marsh covers the largest vertical range and

shows the relative abundance of Ti. comprimata

increasing with elevation to a peak between MHW

and MHHW, before falling in the highest marsh

environment. At Hammock River, a fall in the

relative abundance of Ti. comprimata occurs with

the change in vegetation from Sp. patens to Ph.

australis, perhaps reflecting its preference for more

saline conditions.

M. fusca is commonly encountered in low marsh

environments where it may dominate the assemblage

in association with agglutinated taxa such as Ammot.

salsum, and a range of calcareous species (Patterson,

1990; Gehrels, 1994; De Rijk and Troelstra, 1997).

This pattern is clearly exhibited in the transects

from Pattagansett River marsh, where the abundance

of M. fusca increases rapidly below MHW to

dominate the death assemblage (40–60%). At Dou-

ble Beach, the lowermost samples of transect 1

around MHW capture a peak in M. fusca (30%).

However, whilst the higher elevation samples of this

transect do not contain significant numbers of M.

fusca ( < 7%), it contributes up to 30% of the death

assemblage at comparable elevations in transect 2.

Similarly, at Hammock River, there is an apparent

increase in abundance to c. 10–20% of the death

assemblage with increasing elevation, although M.

fusca is never the dominant species and the lack of

samples from elevations below MHW may account

for this apparently inverse trend in relative abun-

dance. De Rijk and Troelstra (1997) note that at

Barnstable, Massachusetts, whilst M. fusca is dom-

inant in the low marsh, it can also be locally

abundant (up to 20%) in the high marsh above

MHW, where it may be correlated with sandier

substrates or higher flooding frequency.

5.1. Vertical assemblage zones in Connecticut

The foraminiferal death assemblages from each of

the sites described above are grouped by cluster

analysis (see Section 2.4). Fig. 6 presents foraminif-

eral assemblage zones for each of the study sites,

based on this analysis and plotted relative to MHW.

In the case of Double Beach and Pattagansett, the

assemblage zones are composites of both transects at

each site. In addition, the foraminiferal zones for

Nova Scotia, adapted from Scott and Medioli (1978,

1980a), are included for comparison. The vertical

offset of the various zones reflects inter-site differ-

ences in tidal range.

The assemblage zones illustrate that, in contrast

to reports from some sites in New England (e.g., De

Rijk and Troelstra, 1997), foraminiferal assemblages

in Connecticut do exhibit vertical zonation, although

other parameters (e.g., salinity) introduce variability

within and between marshes. Furthermore, the diag-

Fig. 6. Vertical assemblage zones for each study marsh based on cluster analysis of the foraminiferal death assemblage. Zones are plotted

relative to local mean high water and demonstrate the spatial heterogeneity apparent in modern surface distributions. The Nova Scotia vertical

zonation of Scott and Medioli (1980a) is included for reference.


nostic faunal assemblage zone 1A is recorded at two

of the three study marshes and varies in thickness

from 5 to 10 cm. However, its distribution is

apparently spatially variable within sites as indicated

by the failure of single transects to locate it. It is

therefore possible that additional surveys at Ham-

mock River marsh may reveal its presence.

The variability expressed between these transects

may reflect the contrasting nature of the depositional

environment and substrate encountered at the rear of

these marshes. Both transects that record faunal

assemblage zone 1A have ‘natural’ transitions from

highest marsh into upland. For example, at Double

Beach, the upper portion of transect 2 is character-

ised by a comparatively moist, vegetated surface

associated with some leaf litter beneath the fringing

marsh woodland. Despite this apparently supra-tidal

setting, a large percentage of living foraminifera are

recorded (20%), and a higher proportion of larger

test sizes are present than compared with other

samples from the high marsh. This environment

contrasts strongly with the upper portion of transect

1, which is characterised by a dry, bare sediment

surface beneath a canopy of I. frutescens. Here, the

living component of the assemblage is very small

(0–2%). Similarly, at Pattagansett River, transect 1

terminated in shrubs whilst transect 2 was sampled

on dry, loose sandy soil beneath an open canopy of

I. frutescens adjacent to a car park. Finally, the

upper assemblage zone at Hammock River was

recovered from behind a dense stand of Phragmites

backed by a small ditch and bank. Despite this

indicator of lower salinity conditions, H. manilaen-

sis contributes on average only 8% of the total

assemblage.

These results suggest that monospecific J. macres-

cens assemblages are best developed in areas where

‘natural’ transitions to upland environments are en-

countered, and that careful sampling is required to

locate suitable modern analogue environments. This is

increasingly difficult since most marsh areas have been

ditched and are backed by embankments, roads, and


other built structures. The abundance of monospecific

J. macrescens assemblages in fossil samples may

reflect the fact that undisturbed marsh to woodland

transitions were more common and covered much

larger areas than they do today.

5.2. Application in sea-level research

An ideal sea-level indicator will possess a consis-

tent vertical relationship to a defined element of the

tidal frame (termed the indicative meaning). In

reality, most indicators express a range of vertical

relationships (called the indicative range) that

imparts a fundamental limit on the precision to

which past tide levels can be reconstructed. The

Connecticut assemblage zones presented in Fig. 6

demonstrate that individual zones exhibit differing

vertical ranges. For example, the 100% J. macres-

cens zone has a vertical range between 5 and 10 cm,

whilst the other assemblage zones are typically 20–

40 cm thick. As a consequence of this type of

variability, the position of a sample relative to the

tidal frame, coupled with the local tidal range, will

determine the precision of the associated reconstruc-

tion. Furthermore, similar assemblage zones and

zone boundaries possess different indicative mean-

ings depending on which study site is used as a

reference. This means that the use of vertical

assemblages zones derived from other sites is prone

to error, even if adjustments are made for differences

in tidal range. This is of particular significance given

the spatial variability encountered in surface forami-

niferal distributions and the nature of modern

marshes, since it may not be possible to collect a

representative suite of modern analogues from the

same site that fossil material is extracted.

A further problem with the use of assemblage zones

is the low and variable resolution to which changes in

environment can be distinguished. This arises because

changes can only be detected when a transition be-

tween assemblage zones occurs. This restricts the

provenance of useful sea-level information to a limited

number of critical thresholds that equate to a small sub-

set of environmental conditions within a salt-marsh

system. The result of this will be at best a punctuated

signal of sea-level change and, where the vertical

ranges of assemblage zones are large and changes in

sea-level small, no record of change at all.

In an attempt to circumvent the problems of low

resolution associated with the use of assemblage

zones, Thomas and Varekamp (1991) employed a

modified version of the vertical zonation reported by

Scott and Medioli (1978, 1980a) to develop marsh

palaeoenvironmental curves that expressed marsh-

surface elevation relative to the tidal frame. Infor-

mation on elevation was derived from an index of

flooding frequency, based on the proportion of Tr.

macrescens (or its corollary ‘% other species’). The

resulting reconstructions with a resolution of 5 cm

(Varekamp et al., 1992) have become incorporated in

the sea-level research of the region (Nydick et al.,

1995; van de Plassche et al., 1998; van de Plassche,

2000). The spatial variability apparent in the Con-

necticut marshes complicates the extrapolation of

zonations from outside the study area and recom-

mends that future sea-level investigation in the

Connecticut region should be based on local modern

analogues. In contrast to some sites in Maine (Geh-

rels and van de Plassche, 1999), the modern distri-

butions from Connecticut indicate that the

abundance of J. macrescens does not vary uniformly

with elevation, even when sampling is restricted to

high marsh environments above mean high water.

The use of a single foraminifera species as a sea-

level indicator is therefore prone to error. A more

reliable approach is to use assemblages of forami-

nifera that can exploit the varying sensitivities and

tolerances of individual taxa across a range of

elevations.

6. Summary and conclusions

The salt-marshes of Connecticut and its neigh-

bouring states have become prominent in the sea-

level literature as the home of high-resolution

reconstructions investigating the relationship be-

tween ocean and climate change. Whilst these

studies use salt-marsh foraminifera as sea-level indi-

cators, comparatively little published data regarding

their surface distributions in the modern marshes of

Connecticut exist. These types of data are of par-

ticular importance given the apparent lack of verti-

cal zonation recorded in neighbouring salt-marshes

of Massachusetts (De Rijk, 1995b; De Rijk and

Troelstra, 1997).


The high marsh surface foraminiferal distributions

from three sites in Connecticut presented here indi-

cate that whilst the vertical zonation concept pro-

posed by Scott and Medioli (1978, 1980a) is

applicable to the marshes of Connecticut, there are

some important limitations that must be taken into

consideration before it can be applied to produce

reliable sea-level reconstructions from fossil materi-

al. Comparison of data from these and other sites in

neighbouring areas demonstrates that there is signif-

icant intra- and inter-site variability in the occur-

rence and distribution of individual salt-marsh

foraminiferal species. Individual taxa rarely vary

uniformly with elevation and vertical relationships

with the tidal frame differ within and between sites.

This complicates the use of single indicator species

and means that vertical relationships derived from

marshes with markedly different hydrographic, phys-

iographic, vegetative or climatic characteristics are

potentially erroneous.

This spatial heterogeneity is reflected in local

vertical foraminiferal assemblage zones as differences

in composition, indicative meaning and indicative

range. This compounds the problems of limited and

variable precision inherent in the assemblage zone

approach, which means that reconstructions are re-

stricted to sediments representing a sub-set of envi-

ronmental conditions and are associated with errors of

varying magnitude.

Whilst the heterogeneity described above suggests

that local fauna–environment relationships are to be

preferred, the disturbance of salt-marshes by human

activity means that it may not be possible to collect a

full range of modern analogues from every study

marsh. Furthermore, environmental changes at a site

may produce extant populations that differ in compo-

sition to sub-fossil assemblages. In such instances, it

may be necessary to collect appropriate modern ana-

logues from other marshes or regions, but this must be

done in a way that accounts for the spatial variability

outlined above.

The problems associated with using assemblage

zones can be circumvented by adopting an approach

that still considers assemblages as a whole, but is

capable of discerning more subtle variations in the

abundance of individual species. The use of forami-

niferal transfer functions offers one means of achiev-

ing this since they assign ecological optima and

tolerances to individual species, but produce recon-

structions based on assemblages as a whole (Guil-

bault et al., 1996; Horton et al., 2000; Edwards and

Horton, 2000; Gehrels, 2000). In addition, they can

combine data from a number of marshes to ensure

that a wide range of modern analogues can be

collected, whilst quantifying the variability within

these assemblages. In this way, complementary sites

can be selected to combine desirable attributes such

as a long stratigraphic sequence indicative of high

marsh deposition, and a relatively pristine, unaltered

modern salt-marsh.

Gehrels (2000) successfully applied a foraminif-

eral transfer function to salt-marsh assemblages

from Maine and demonstrated its reliability and

utility in resolving decadal-scale sea-level changes.

Differences in the occurrence and distribution of

foraminiferal species between Maine and Connecti-

cut (e.g., B. pseudomacrescens) mean that the

application of this transfer function in Connecticut

is prone to error unless local assemblages are

included in the data used to derive fauna–environ-

ment relationships (termed a ‘training set’). The

new foraminiferal data presented here form the basis

of such a modern training set which, in combination

with other data from Connecticut, is suitable for the

derivation of a transfer function for tide level

reconstruction in this area.

Acknowledgements

The manuscript was prepared at Trinity College

Dublin and was facilitated by a Trinity award. We

thank Wilfried Goossen (Vrije Universiteit) for his

assistance in the field. Thanks are also due to Ben

Horton (Durham University) for the helpful comments

and discussion. This research is a contribution to the

project ‘‘Coastal Records’’, currently funded by the

Vrije Universiteit Amsterdam. The manuscript was

significantly improved by the thoughtful comments of

two anonymous reviewers.


Appendix A. Systematic taxonomy

Ammot. salsum (Cushman and Bronnimann)

Ammobaculites salsus Cushman and Bronnimann, 1948, p. 16, pl. 3, figs. 7–9.

Ammot. salsum (Cushman and Bronnimann), Scott and Medioli, 1980a, p. 35, pl. 1, figs. 11–13.

Areno. mexicana (Kornfeld)

Plate 1 : Figs. 1–2.

Tr. inflata (Montague) var. mexicana Kornfeld, 1931, p. 86, pl. 13, fig. 5.

Areno. mexicana (Kornfeld), Andersen, 1951, p. 31, figs. 1a–c.

Areno. mexicana (Kornfeld), Scott and Medioli, 1980a, p. 35, pl. 1, figs. 8–11.

B. pseudomacrescens Bronnimann, Lutze and Whittaker

Tr. macrescens Lutze, 1968, pp. 25–26, tafel 1, fig. 9.

Tr. inflata (Montagu) var. macrescens Scott, 1976, p. 320, pl. 1, figs. 4–7.

Tr. macrescens macrescens Scott et al., 1990, p. 733, pl. 1, figs. 1a–b.

B. pseudomacrescens Bronnimann et al., 1989, p. 169, pl. 1–3.

B. pseudomacrescens (Bronnimann, Lutze and Whittaker), Gehrels and van de Plassche, 1999, p. 98, pl. 1,

figs. 6–10.

J. macrescens (Brady)

Plate 1: Figs. 3–4.

Tr. inflata (Montagu) var. macrescens Brady, 1870, p. 290, pl. 11, fig. 5a–c.

Jadammina polystoma Barnstein and Brand, 1938, p. 381, figs. 1a–c, 2a– l; Parker and Athearn, 1959, p. 341,

pl. 50, figs. 21–22, 27.

Tr. macrescens Brady, Phleger and Walton, 1950, p. 281, pl. 2, figs. 6–9; Parker and Athearn, 1959, p. 341,

pl. 50, figs. 23–25.

Trochammina macrescens polystoma Scott et al., 1990, p. 737, pl. 1, fig. 2a–c.

J. macrescens (Brady), Murray, 1971, p. 41, pl. 13, figs. 1–5; Bronnimann and Whittaker, 1984, p. 305,

figs. 1–21; Gehrels and van de Plassche, 1999, p. 98, pl. 1, figs. 1–5.

H. manilaensis (Anderson)


H. manilaensis (Anderson, 1953, p. 22), pl. 4, figs. 8a–b.

Haplophragmoides bonplandi (Todd and Bronnimann), Scott and Medioli, 1980a, p. 40, pl. 2, figs. 4–5.

H. manilaensis (Anderson), Thomas and Varekamp, 1991, p. 155; De Rijk, 1995a, p. 29, pl. I, figs. 1–8.

M. fusca (Brady)

Plate 1: Fig. 7.

Quinqueloculina fusca Brady, in Brady and Robertson, 1870, p. 47, pl. 11, figs. 2–3.

M. fusca (Brady), Phleger and Walton, 1950, p. 280, pl. 1, figs. 19a–b; Scott and Medioli, 1980a, pp. 40–41,

pl. 2, figs. 1–3.

Polysaccammina ipohalina Scott

Po. ipohalina Scott, 1976, p. 318, pl. 2, figs. 1–4.

Po. ipohalina Scott, Scott and Medioli, 1980a, p. 43, pl. 2, figs. 8–11.

Pseudothurammina limnetis (Scott and Medioli)

Plate 1: Fig. 8.

Thurammina ? limnetis Scott and Medioli, 1980a, p. 43, pl. 1, figs. 1–3.

Ps. limnetis (Scott and Medioli), Scott et al., 1981, p. 126.

Reophax species

Genus Rheophax Montfort, 1808

Appendix A (continued)

Si. lobata Saunders


Si. lobata Saunders, 1957, pp. 9–10, pl. 3, figs. 1–2; Bronnimann et al., 1992, p. 31, pl. 4, figs. 1–2;

De Rijk, 1995a, p. 33, pl. III, figs. 9, 11–13.

Textularia earlandi Parker

Plate 1: Fig. 11.

Te. earlandi Parker, 1952, p. 458 (footnote).

Te. earlandi Parker, Scott et al., 1990, p. 732.

Ti. comprimata (Cushman and Bronnimann)


Trochammina comprimata Cushman and Bronnimann, 1948, p. 41, pl. 8, figs. 1–3.

Ti. comprimata (Cushman and Bronnimann), Scott and Medioli, 1980a, p. 44, pl. 5, figs. 1–3.

Tr. inflata (Montagu)


Nautilus inflatus Montagu, 1808, p. 81, pl. 18, fig. 3.

Tr. inflata (Montagu), Phleger and Walton, 1950, p. 280, pl. 2, figs. 1–3.

Tr. inflata (Montagu), De Rijk, 1995a, p. 31, pl. 2, figs. 1–3.

Trochammina ochracea (Williamson, 1858)

Rotalina ochracea Williamson, 1858, p. 55, pl. 4, fig. 112, pl. 5, fig. 113.

Tr. ochracea (Williamson), Cushman, 1920, p. 75, pl. 15, fig. 3.


Plate 1. Scale bars equivalent to 100 Am. (1). Areno. mexicana, dorsal view (Double Beach marsh, surface). (2) Areno. mexicana, aperture view

(Double Beach marsh, surface). (3) J. macrescens, ventral view (Double Beach marsh, surface). (4) J. macrescens, dorsal view (Double Beach

marsh, surface). (5) H. manilaensis, aperture view (Double Beach marsh, surface). (6) H. manilaensis, side view (Double Beach marsh, surface).

(7) M. fusca, side view (Pattagansett River marsh, surface). (8) Ps. limnetes (Double Beach marsh, surface). (9) Si. lobata, dorsal view (Double

Beach marsh, surface). (10) Si. lobata, ventral view (Double Beach marsh, surface). (11) Te. earlandi (Pattagansett River marsh, surface). (12)

Ti. comprimata, ventral view (Pattagansett River marsh, surface). (13) Ti. comprimatai, dorsal view (Pattagansett River marsh, surface). (14) Tr.

inflata, dorsal view (Double Beach marsh, surface). (15) Tr. inflata, ventral view (Double Beach marsh, surface).


Table B1

Foraminiferal death assemblages from Double Beach marsh

Transect Sample Notes Altitude

(m NGVD)

Ammot.

salsum

Areno.

mexicana

B.

pseudomacrescens

J.

macrescens

H.

manilaensis

M.

fusca

Ps.

limnetis

Si.

lobata

Te.

earlandi

Ti.

comprimata

Tr.

inflata

Not

ID

Calcareous Dead

tests

counted

1 DB1-11 I. frutescens 1.57 50 28 6 5 2 91

1 DB1-10 I. frutescens 1.54 113 43 11 7 10 1 185

1 DB1-9 I. frutescens 1.47 105 28 2 16 88 1 240

1 DB1-8 Scirpus sp. 1.42 1 366 84 11 93 2 271 4 832

1 DB1-7 Scirpus sp. 1.37 7 1 339 19 8 40 279 693

1 DB1-6 Scirpus sp. 1.32 10 414 1 9 44 1 5 123 2 609

1 DB1-5 Juncus

gerardii

1.27 84 1099 8 13 258 3 65 477 8 1 2016

1 DB1-4 Sp. patens 1.22 31 249 7 2 44 6 11 81 7 5 443

1 DB1-3 Sp.

alterniflora

(stunted)

1.18 8 209 1 7 29 4 6 46 2 6 318

1 DB1-2 Sp.

alterniflora

(stunted)

1.12 1 108 55 3 2 17 2 2 190

1 DB1-1 Sp.

alterniflora

(stunted)

1.08 4 509 50 1 20 6 217 3 13 823

2 DB2-27 Woodland 1.63 75 75

2 DB2-26 Woodland 1.58 166 166

2 DB2-25 Wood fringe 1.53 1 141 1 6 8 157

2 DB2-24 Scirpus sp. 1.48 171 79 3 253

2 DB2-23 Scirpus sp. 1.43 262 120 2 1 385

2 DB2-22 Scirpus sp. 1.38 1 140 58 43 7 16 17 9 5 296

2 DB2-21 Scirpus sp. 1.33 1 129 68 35 3 41 9 7 293

2 DB2-20 Scirpus sp. 1.28 1 123 21 38 28 4 15 1 231

2 DB2-19 Sp. patens 1.28 2 254 9 15 2 67 33 79 1 462

Unidentified specimens refer to deformed or small (juvenile?) tests.

Appendix B. Foraminiferal counts

R.J.

Edwardset

al./Marin

eMicro

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ntology51(2004)1–21

17

Table B2

Foraminiferal death assemblages from Hammock River marsh

Sample Notes Altitude

(m NGVD)

Ammot.

salsum

Areno.

mexicana

B.

pseudomacrescens

J.

macrescens

H.

manilaensis

M.

fusca

Po.

ipohalina

P.

limnetis

Si.

lobata

Te.

earlandi

Ti.

comprimata

Tr.

inflata

Tr.

ochracea

Not

ID

Dead

tests

counted

HRM-1 Fringing

Woodland

1.42 10 2 2 14

HRM-2 Fringing

Woodland

1.37 54 12 6 72

HRM-3 Fringing

Woodland

1.29 44 1 7 7 59

HRM-4 Bare 1.25 47 3 9 5 65

HRM-5 Bare 1.19 43 5 18 7 1 1 75

HRM-6 Bare 1.13 67 5 14 1 7 2 96

HRM-7 Ph. australis 1.09 4 100 14 13 1 2 1 1 2 2 140

HRM-8 Ph. australis 1.06 1 76 25 5 1 17 9 6 140

HRM-9 Sc. robustus 1.04 90 29 12 1 35 23 34 2 226

HRM-10 Sp. patens 1.02 58 32 19 2 2 15 47 1 176

HRM-11 Sp. patens 0.97 1 85 2 1 11 12 20 132

HRM-12 Sp. patens 0.92 6 2 100 11 3 35 1 18 29 2 207

HRM-13 Sp.

alterniflora

(stunted)

0.87 9 188 19 38 1 44 66 3 368

HRM-14 Sp.

alterniflora

(stunted)

0.83 32 133 12 1 21 17 45 1 4 266


R.J.

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ntology51(2004)1–21

18

Table B3

Foraminiferal death assemblages from Pattagansett River marsh

Transect Sample Notes Altitude

(m NGVD)

Ammob.

dilatatus

Ammot.

salsum

Areno.

mexicana

B.

pseudomacrescens

J.

macrescens

H.

manilaensis

M.

fusca

Po.

ipohalina

Reophax

sp.

S.

lobata

Te.

earlandi

Ti.

comprimata

Tr.

inflata

Not ID Calcareous Dead

tests

counted

1 PAT1-3 I. frutescens 1.05 87 3 90

1 PAT1-4 I. frutescens 1.00 57 1 1 59

1 PAT1-5 I. frutescens 0.95 4 117 1 2 29 153

1 PAT1-6 I. frutescens 0.93 1 61 4 7 2 170 245

1 PAT1-7 I. frutescens 0.90 2 72 20 18 1 5 7 440 565

1 PAT1-8 I. frutescens 0.85 72 19 7 42 3 261 404

1 PAT1-9 I. frutescens 0.80 57 13 4 11 10 177 272

1 PAT1-10 Sp. patens 0.75 1 143 19 2 29 46 119 359

1 PAT1-11 Sp. patens 0.70 3 123 24 22 56 64 292

1 PAT1-12 Sp. patens 0.65 2 1 113 49 23 2 33 45 268

1 PAT1-13 Sp. patens 0.60 4 9 147 21 54 3 51 190 479

1 PAT1-14 Sp. alterniflora

(stunted)

0.55 6 9 57 241 44 2 50 46 1 456


(stunted)

0.5 19 2 23 147 9 15 13 228


(tall)

0.45 35 16 23 77 7 6 2 1 23 10 200


(tall)

0.40 1 41 19 36 110 9 7 5 21 1 250


(tall)

0.35 8 44 41 146 4 23 1 14 58 3 342

2 PAT2-18 I. frutescens 0.99 31 1 3 2 12 49

2 PAT2-17 I. frutescens 0.94 251 5 1 291 548

2 PAT2-16 I. frutescens 0.89 144 3 5 155 307

2 PAT2-15 I. frutescens 0.85 218 2 16 272 508

2 PAT2-14 Distichlis

spicata

0.80 377 4 48 1 601 1031

2 PAT2-13 Sp. patens 0.75 1 275 1 25 13 9 166 490

2 PAT2-12 Sp. patens 0.69 87 1 1 8 30 56 3 186

2 PAT2-11 Sp. patens 0.65 2 5 130 31 3 2 20 35 228

2 PAT2-10 Sp. patens 0.60 3 56 1 115 11 1 5 59 251

2 PAT2-9 Sp. patens 0.55 1 7 146 0 214 20 8 79 1 2 478


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ntology51(2004)1–21

19


References

Andersen, H.V., 1951. Two new genera of Foraminifera from

recent deposits in Louisiana. Journal of Paleontology 25,

31–34.

Barnstein, H., Brand, E., 1938. Die foraminiferan-fauna des jade-

gebietes. Senckenbergiana 20 (323), 381–385.

Brady, H.B., 1870. With analysis and descriptions of Foraminifera.

In: Brady, G.S., Robertson, D. (Eds.), The Ostracoda and For-

aminifera of tidal rivers, Annual Magazine of Natural History,

Series, 4 (6), 273–306.

Bronnimann, P., Whittaker, J.E., 1984. A lectotype for Jadammina

macrescens (Brady) and emendation of Jadammina barnstein

and brand (Protozoa: foraminiferida). Bulletin of the British

Museum, Natural History. Zoology 46 (4), 303–309.

Bronnimann, P., Lutze, G.F., Whittaker, J.E., 1989. Balticammina

pseudomacrescens, a new brackish Trochamminid from the

western Baltic Sea, with remarks on the wall structure. Meyni-

ana 41, 167–177.

Bronnimann, P., Whittaker, J.E., Zaninetti, L., 1992. Brackish water

foraminifera from mangrove sediments of south-western Viti

Levu, Fiji Islands Southwest Pacific. Revue Paleobiologie 11

(1), 13–65.

Cushman, J.A., 1920. The foraminifera of the Atlantic Ocean: Part

2. Lituolidae. Bulletin of the US National Museum, Smithsonian

104, 1–111.

Cushman, J.A., Bronnimann, P., 1948. Additional new species of

Arenaceous foraminifera from the shallow waters of Trinidad.

Contributions from the Cushman Laboratory for Foraminiferal

Research 24, 37–42.

De Rijk, S., 1995a. Agglutinated foraminifera as indicators of salt

marsh development in relation to late holocene sea level rise

(Great Marshes at Barnstable, Massachusetts) Febo, Utrecht.

188 pp.

De Rijk, S., 1995b. Salinity control on the distribution of salt marsh

foraminifera (Great Marshes, Massachusetts). Journal of Fora-

miniferal Research 25 (2), 156–166.

De Rijk, S., Troelstra, S.R., 1997. Saltmarsh foraminifera from the

Great Marshes, Massachusetts: environmental controls. Palae-

ogeography, Palaeoclimatology, Palaeoecology 130, 81–112.

Dreyer, G.D., Niering, W.A., 1995. Tidal marshes of Long Island

Sound: ecology, history and restoration. Bulletin-Connecticut

College Arboretum, 34.

Edwards, R.J., Horton, B.P., 2000. Reconstructing relative sea-level

change using UK salt-marsh foraminifera. Marine Geology 169

(1–2), 41–56.

Gehrels, W.R., 1994. Determining relative sea-level change from

salt-marsh foraminifera and plant zones on the coast of Maine,

USA. Journal of Coastal Research 10 (4), 990–1009.

Gehrels, W.R., 2000. Using foraminiferal transfer functions to pro-

duce high-resolution sea-level records from salt-marsh deposits,

Maine, USA. The Holocene 10 (3), 367–376.

Gehrels, W.R., van de Plassche, O., 1999. The use of Jadammina

macrescens (Brady) and Balticammina pseudomacrescens Bron-

nimann, Lutze and Whittaker (Protozoa: foraminiferida) as sea-

level indicators. Palaeogeography, Palaeoclimatology, Palaeoe-

cology 149, 89–101.

Goldstein, S.T., Watkins, G.T., 1999. Taphonomy of salt marsh

foraminifera: an example from coastal Georgia. Palaeogeogra-

phy, Palaeoclimatology, Palaeoecology 149, 103–114.

Grimm, E., 1991–1993. Tilia. release 2.0 b.0.5 Illinois State Mu-

seum, Springfield, IL.

Guilbault, J., Clague, J.J., Lapointe, M., 1996. Foraminiferal evi-

dence for the amount of coseismic subsidence during a late

Holocene earthquake on Vancouver Island, west coast of Cana-

da. Quaternary Science Reviews 15, 913–937.

Horton, B.P., 1997. Quantification of the indicative meaning of a

range of Holocene sea-level index points from the western

North Sea. Unpublished PhD thesis. Department of Geography,

University of Durham, UK.

Horton, B.P., Edwards, R.J., Lloyd, J.M., 1999. Reconstruction of

former sea-levels using a foraminiferal-based transfer function.

Journal of Foraminiferal Research 29 (2), 117–129.

Horton, B.P., Edwards, R.J., Lloyd, J.M., 2000. Implications of a

microfossil transfer function in Holocene sea-level studies. In:

Shennan, I., Andrews, J.E. (Eds.), Holocene Land–Ocean In-

teraction and Environmental Change Around the Western North

Sea. Geological Society, London, Special Publications, vol. 166,

pp. 41–54.

Jennings, A.E., Nelson, A.R., 1992. Foraminiferal assemblage

zones in Oregon tidal marshes—relation to marsh floral zones

and sea level. Journal of Foraminiferal Research 22, 13–29.

Kornfeld, M.M., 1931. Recent littoral foraminifera from Texas and

Louisiana. Standford University Department of Geology Con-

tributions 1 (3), 77–101.

Lutze, G.F., 1968. Jahresgang der Foraminiferan-Fauna in der Bott-

sand-Lagune (wesliche Ostsee). Meyniana 18, 13–30.

Montagu, G., 1808. Testacea Britanica, Supplement. S. Woolmer,

Exeter, England, pp. 1–83.

Murray, J.W., 1971. Living foraminiferids of tidal marshes: a re-

view. Journal of Foraminiferal Research 1, 153–161.

Murray, J.W., 1991. Ecology and Palaeoecology of Benthic Fora-

minifera, 1st ed. Longman, New York.

Murray, J.W., 2000. The enigma of the continued use of total as-

semblages in ecological studies of benthic foraminifera. Journal

of Foraminiferal Research 30 (3), 244–245.

Murray, J.W., Bowser, S.S., 2000. Mortality, protoplasm decay

rate, and reliability of staining techniques to recognize ‘living’

foraminifera: a review. Journal of Foraminiferal Research 30,

66–70.

Nydick, K.R., Bidwell, A.B., Thomas, E., Varekamp, J.C., 1995.

A sea-level rise curve from Guilford, CT, USA. Marine Geol-

ogy 124, 137–159.

Ozarko, D.L., Patterson, R.T., Williams, H.F.L., 1997. Marsh fora-

minifera from Nanaimo, British Columbia (Canada): implica-

tions of infaunal habitat and taphonomic biasing. Journal of

Foraminiferal Research 27 (1), 51–68.

Parker, F.L., 1952. Foraminiferal distribution in the Long Island

Sound–Buzzards Bay area. Bulletin of the Museum of Compa-

rative Zoology, Harvard College 106, 438–473.

Parker, F.L., Athearn, W.D., 1959. Ecology of marsh foraminifera

in Poponesset Bay, Massachusetts. Journal of Paleontology 33

(2), 332–343.

Patterson, R.T., 1990. Intertidal benthic foraminiferal biofacies on


the Fraser River Delta, British Columbia: modern distribu-

tion and palaeoecological importance. Micropaleontology 36,

229–244.

Phleger, F.B., Walton, W.R., 1950. Ecology of marsh and Bay

Foraminifera, Barnstable, Massachusetts. American Journal of

Science 248, 274–294.

Redfield, A.C., 1972. Development of a New England salt marsh.

Ecological Monographs 42, 201–237.

Saffert, H., Thomas, E., 1998. Living foraminifera and total po-

pulations in salt marsh peat cores: Kelsey Marsh (Clinton, CT)

and the Great Marshes (Barnstable, MA). Marine Micropaleon-

tology 33, 175–202.

Saunders, J.B., 1957. Trochamminidae and certain lituolidae (fora-

minifera) from the recent brackish water sediments of Trinidad,

British West Indies. Smithsonian Miscellaneous Collections 134

(5), 1–23.

Scott, D.B., 1976. Quantitative studies of marsh foraminiferal

patterns in Southern California and their application to Holo-

cene stratigraphic problems. First International Symposium on

Benthonic Foraminifera of Continental Margins (Part A: Ecol-

ogy and Biology).Maritime Sediments Special Issue, vol. 1,

pp. 153–170.

Scott, D.K., Leckie, R.M., 1990. Foraminiferal zonation of Great

Sippewissett Salt Marsh (Falmouth, MA). Journal of Foramini-

feral Research 20 (3), 248–266.

Scott, D.B., Medioli, F.S., 1978. Vertical zonations of marsh fora-

minifera as accurate indicators of former sea-levels. Nature 272,

528–531.

Scott, D.B., Medioli, F.S., 1980a. Quantitative studies of marsh

foraminiferal distributions in Nova Scotia: implications for sea

level studies. Special Publication-Cushman Foundation for For-

aminiferal Research 17.

Scott, D.B., Medioli, F.S., 1980b. Living vs. total foraminiferal

populations: their relative usefulness in paleoecology. Journal

of Paleontology 54, 814–831.

Scott, D.B., Medioli, F.S., 1986. Foraminifera as sea-level indica-

tors. In: van de Plassche, O. (Ed.), Sea-Level Research: A Man-

ual for the Collection and Evaluation of Data. Geo Books,

Norwich, pp. 435–456.

Scott, D.B., Williamson, M.A., Duffet, T.E., 1981. Marsh forami-

nifera of Prince Edward Island: their recent distribution and

application for former sea level studies. Maritime Sediments

and Atlantic Geology 17, 98–129.

Scott, D.B., Schnack, E.J., Ferrero, L., Espinosa, M., Barbosa, C.F.,

1990. Recent marsh foraminifera from the eastern coast of south

America: comparison to the northern hemisphere. In: Hemble-

ben, C. (Ed.), Palaeoecology, Biostratigraphy, Palaeoceaonogra-

phy, and Taxonomy of Agglutinated Foraminifera. Kluwer

Academic Publishing, Dordrecht, pp. 717–737.

Thomas, E., Varekamp, J.C., 1991. Paleo-environmental analyses of

marsh sequences (Clinton, Connecticut): evidence for punctua-

ted rise in relative sealevel during the latest Holocene. Journal of

Coastal Research 11, 125–158.

Van der Molen, J., 1997. Tides in a Salt-Marsh (Great Marshes,

Barnstable, Cape Cod, USA). PhD thesis, Vrije Universiteit

Amsterdam, The Netherlands, Febodruk BV, Enschede, The

Netherlands. 104 pp.

van de Plassche, O., 1991. Late Holocene sea-level fluctuations on

the shore of Connecticut inferred from transgressive and regres-

sive overlap boundaries in salt-marsh deposits. Journal of Coas-

tal Research Special Issue 11, 159–179.

van de Plassche, O., 2000. North Atlantic climate–ocean variations

and sea level in long island sound, Connecticut, since 500 cal yr

AD. Quaternary Research 53, 89–97.

van de Plassche, O., van der Borg, K., De Jong, A.F.M., 1998. Sea

level–climate correlation during the past 1400 yr. Geology 26,

319–322.

Varekamp, J.C., Thomas, E., van de Plassche, O., 1992. Relative

sea-level rise and climate change over the last 1500 years. Terra

Nova 4, 293–304.

Williamson, W.C., 1858. On the recent foraminifera of Great Brit-

ain Ray Society, London. 108 pp.

Documents

Surface distributions of salt-marsh foraminifera from Connecticut