Recent Benthic Foraminifera Research Articles

An 800-year record of benthic foraminifer images and 2D morphometrics from the Santa Barbara Basin

The Santa Barbara Basin is an extraordinary archive of environmental and ecological change, where varved sediments preserve microfossils that provide an annual to decadal record of the dynamics of surrounding ecosystems. Of the microfossils preserved in these sediments, benthic foraminifera are the most abundant seafloor-dwelling organisms. While they have been extensively utilized for geochemical and paleoceanographic work, studies of their morphology are lacking. Here we use a high-throughput imaging method (AutoMorph) designed to extract 2D data from photographic images of fossils to produce a large image and 2D shape dataset of recent benthic foraminifera from two core records sampled from the center of the Santa Barbara Basin that span an ~800-year-long interval during the Common Era (1249–2008 CE). Information on more than 36,000 objects is included, of which more than 22,000 are complete or partially-damaged benthic foraminifera. The dataset also includes other biogenic microfossils including ostracods, pteropods, diatoms, radiolarians, fish teeth, and shark dermal denticles. We describe our sample preparation, imaging, and identification techniques, and outline potential data uses.

Abundance and distribution of recent benthic foraminifera from the southwestern part of the Bay of Bengal

Foraminifers are ubiquitous and abundant organisms in the marine environment, sensitive to different environmental variables such as pH, dissolved oxygen, salinity, temperature, organic matter and substrate. In the present study, environmental variables and benthic foraminiferal assemblages from 32 surface sediment samples belonging to different water depths were studied to understand the shelf and slope environment of the southwestern Bay of Bengal. Statistical methods such as cluster and principal component analysis (PCA) were used to infer the relationship existing among various foraminiferal assemblages, bathymetry, sediment and bottom water characteristics. Statistical analysis yielded four assemblages, of which assemblage-I is dominated by Nonion faba, Rotalidium annectens, Asterorotalia pulchella, Elphidium crispum, and Amphistegina radiata, and is confined to the shallowest inner shelf region (5 to 35 m water depth) with sandy sediments indicating high-energy condition. Assemblage-II is marked by the abundance of Cibicidoides wuellerstorfi, Hanzawaia concentrica, Quinqueloculina agglutinans, Quinqueloculina seminula, Quinqueloculina lamarckiana, Ammonia beccarri, and Ammonia tepida which are associated with the middle shelf region (water depth 35 to 70 m) with sandy to slightly muddy sand sediments. Assemblage-III is dominated by Asterorotalia dentata, Quinqueloculina venusta, Cancris communis, Cassidulina laevigata, and N. costiferum which occur at a depth of 70 to 170 m in the outer shelf, and are highly associated with slightly muddy sand to muddy sand. Whereas, assemblage -IV includes Uvigerina mediterranea, Bolivina dilatata, Bolivina robusta, and Bulimina marginata foraminiferal species that are abundant in the upper slope (170–244 m water depth) and are confined to muddy sand and sandy mud with low dissolved oxygen in the bottom water. The above assemblages depict that the abundance and distribution of foraminifera are largely controlled by substrate, energy conditions and environmental variables such as temperature, salinity, organic matter and dissolved oxygen.

Benthic foraminifera geochemistry as a monitoring tool for heavy metal and phosphorus pollution — A post fish-farm removal case study

Measuring environmental contaminants in coastal areas is critical for monitoring and managing their impacts. Commonly used techniques involve repetitive field sampling, which provides a single moment in time during each effort. In this study, we examine the potential for using foraminifera in monitoring and risk assessment as recorders of bioavailable pollutants. Geochemical analysis of benthic foraminifera (Operculina ammonoides) shells sampled annually at a previous fish farm location showed extremely high levels of copper (Cu), zinc (Zn), and phosphorus (P) during the three years following the fish cages removal, with a general reduction afterwards. Levels of Cu/Ca were still more than 4-fold higher than background levels 10 years after the removal of the fish cages. Based on our finds, it is concluded that the geochemical analysis of recent benthic foraminifera shells can serve as a powerful monitoring tool of bioavailable contaminants in seawater. Additionally, the results highlight the need for heavy metal monitoring near marine aquaculture facilities and suggest that long-term effects extend spatially and temporally far beyond the original point source. Finally, we observed variations in micro-distribution of elements within the top 1–2 μm of the shells, where Cu/Ca, Zn/Ca and P/Ca are consistently higher in the chamber wall than in the septa. This observation is relevant for studies conducting single chamber analyses.

Seasonal Distribution Trends of Benthic Foraminiferal Assemblages from the Saurashtra Coast, Western India

ABSTRACT The coastland of Saurashtra is represented by several estuaries, islands and cliffs. Taxonomy and seasonal distribution of the recent benthic foraminifera along the coastal tracts of the Saurashtra region have been documented. Surface sediments were collected from the fifteen stations of this coast in both pre and post-monsoon. A total of 35 calcareous wall structure bearing species are identified. Characteristically, two shallow larger benthic foraminifera Nummulites venosus and Amphistegina radiata are observed. The assemblages are more diverse during the pre-monsoon than the post-monsoon season. The cluster analysis shows two different clusters based on sediment preference and diversity of the assemblages.

Inner Shelf Substrate Characteristics and Their Impacts on the Distribution of Recent Benthic Foraminifera from the Southern Part of Gulf of Mannar, Southeast Coast of India

The present study elaborates the relationship between sediment characteristics and benthic foraminiferal population distribution from off the coast of Theresapuram, Sippikulam, Mookaiyur and Valinokkam representing the southern part of Gulf of Mannar, Southeast coast of India. A systematic collection of sediment and bottom water samples were made at 28 sampling stations, keeping seven samples each, along the four traverses. The samples were collected for three seasons, representing pre-monsoon (October), post-monsoon/winter (January) and summer (April) and thus the collections amounted to a total of 84 samples. The benthic foraminiferal studies from the sediments collected have led to the recognition of 124 benthic foraminiferal species belonging to 59 genera, 39 families and 21 super families of 5 suborders. Among the 124 species, Ammonia beccarii, A. tepida, Asterotalia infllata, Elphidium advenum, Noninoides boueanum, and Quinqueloculina seminulum are considered to be abundant and widespread in the present study area. It has been observed that the maximum population is observed during summer (April) with 2335 specimens and the minimum with 1934 specimens during monsoon (October). Spatially, the middle segment (stations 3-5) of all traverses of all the collections encounter with relatively higher population. Impact of spatial and seasonal variation in substrate characteristics on the benthic foraminiferal population revealed that the calcium carbonate content shows a positive correlation with the fauna of the study area and the organic matter content has somewhat inverse relationship with the population abundance. In the present study, organic matter content is not an effective factor that controls the population abundance, but along with other parameters plays a supporting role. Out of 12 possible sediment types of Trefethen’s classification, the sediments in the study area fall only in three types’ viz., sand, siltysand and claysand. The most favourable substrate for higher benthic foraminiferal population seems to be siltysand. In general, the benthic foraminiferal population of the present study is directly proportional to the calcium carbonate content of the sediments along with lower organic matter (0.7 -0.93%) and the accommodative substrate for higher reproduction is silty sand.

Punctuationlism and Gradualistic Evolutionary Trends of Eight Phylogenetic Lineages of Maastrichtian to Eocene and Recent Benthic Foraminifera from the Tethys

Minor differences in the morphology of the test, wall structure, arrangement of chambers and apertures, size are recognized as being of decisive specific or subspecific value. Twenty four phylogenetic lineages were produced by puncuated equilibrium and gradualistic evolutionary trends which observed within 50 benthic foraminiferal species and subspecies belonging to 18 genera throughout the Maastrichtian to Priabonian forms in Tethys as well as one recent species by the present authors and others. In this study, new eight lineages are presented: Clavulina parisiensis d'Orbigny ˃ C. pseudoparisensis Anan, Laevidentalina granti (Plummer) ˃ L. salimi Anan, Lenticulina carinata (Plummer) ˃ L. turbinata (Plummer) ˃ L. chitanii (Yabe and Asano), Percultazonaria ameeri Anan ˃ P. allami Anan, Percultazonaria alii Anan ˃ P. longiscata (Nakkady), Percultazonaria wadiarabensis (Futyan) ˃ P. tuberculata (Plummer), Palmula woodi undulata Nakkady ˃ P. w. woodi Nakkady, Gavelinella b. brotzeni Said and Kenawy ˃ G. brotzeni paleocenica Said and Kenawy. These lineages help, not only to define the major faunal changes at the Cretaceous/Tertiary (K/T) and the Paleocene/Eocene (P/E) boundaries, but also to emphasis the stratigraphic importance of them in different localities in the Tethys.

Three new records of recent benthic Foraminifera from Korea

Three new records of recent benthic Foraminifera from Korea

Channel Controlled Foraminiferal Distribution off Bakkhali, West Bengal, India

Study area is situated 8 km south of the Bakkhali Island, West Bengal of India and its subaqueous environment influenced by the fluvial processes such as Hooghly River in west and its distributary like Muri Ganga in the centre and Saptamukhi River in the east. To understand the submarine behavior of these channels and associated meiobenthos, total of 28 sediment samples have been studied in detail. The study reveal that a total of fifteen species of recent benthic foraminifera belonging to 13 genera under 11 families were present and their distribution mainly controlled by channel morphology and sediment character. Based on the distribution of these benthic foraminiferal species, two assemblages have been identified. First assemblage, observed within the Hooghly and Muri Ganga channel, where salinity is comparatively low and sediment is mainly dominated by silt and clay. The most dominating benthic foraminifers of this assemblage are Ammobaculites agglutinans, Cribrostomoides jeffreysii and Asterorotalia trispinosa. Whereas, second assemblage mainly comprise of A. trispinosa, Ammonia beccarii, Asterorotalia spp., Elphidium excavatum, Elphidium crispum and Ammonia tepida noticed over the sand bars and adjoining shallow area. Keywords: channel morphology, Muri Ganga, Hooghly, sand bar

Foraminifera from the 58th and 59th Russian Antarctic Expeditions, 2013-2014

Foraminifera were examined in samples collected during the 58th (2013) and 59th Russian Antarctic Expeditions (2013-2014) in the Western and Eastern Antarctic areas in the Bellingshausen Sea, Bransfield Strait, Prydz Bay, Davis Sea, and Southern Ocean at depths between 107 and 995 meters, with the majority of samples situated in the shelf zone. In total 39 benthic and one planktonic species were found. All the benthic species are pan-Antarctic, only Neogloboquadrina pachyderma shows a bipolar distribution. The assemblages at several stations were fully or predominantly agglutinated, possibly as a consequence of dissolution processes, at some others - predominantly or fully calcareous. Calcareous forms prevailed at relatively shallow depths (70-220 m). Among the calcareous species miliolids prevail, their magnesium containing shells are obviously more resistant to dissolution processes. Foraminifera of all the samples were recent and living, containing cytoplasm. The new data on the distribution of the recent benthic foraminifera permits a better understanding of the paleoecological conditions of the geological past. The new data obtained are also important for the comparison of the marine biotas in the Western and Eastern parts of Antarctica.

Taxonomy and Distribution of Recent Benthic Foraminifera from Bir Ali Beach, Shabwah Governorate, Arabian Sea, Yemen

One hundred and eleven benthic foraminiferal species belonging to 36 genera, 25 families, 16 superfamilies and 4 suborders were identified from twenty samples collected from Bir Ali beach on the Yemeni Arabian Sea coastline. The benthic foraminifera assemblages were dominated by species belonging to Miliolina suborder with 71 species and 17 genera, followed by Rotaliina with 29 species and 14 genera, Textulariina 9 species and 3 genera and Lagenina 2 species and 2 genera. The distribution of recent shallow-water benthic foraminifera in surface sediment samples is in varians from sample to another. Higher abundance of genus Quinqueloculina is recorded in almost all the samples of the study area. The recorded assemblages show a high similarity to the foraminiferal assemblages of the IndoPacific region, East African coast and Red Sea.

Recent Benthic Foraminifera as ecological indicators in Manzala Lagoon, Egypt

This study aims to analyze the community of benthic foraminifera in the sediments of Manzala lagoon and investigate the impacts of trace metals on foraminifera. This lagoon is subjected to high input of anthropogenic pollutants from industrial, domestic and agricultural sources, which enter into the lagoon through some drains and canals. Twenty-four surficial sediment samples were taken by a grab sampler during February 2015. Some trace metals (Cu, Mn, Zn and Pb) were analyzed. Based on the contamination indices, Manzala Lagoon could be classified into three main regions: the southern part which exhibited the highest levels of pollution, the middle part of a considerable degree and the northern part of a low degree of pollution. Eight foraminiferal species, belonging to 5 genera were identified. The abundance of Ammonia beccarii and A. tepida may be due to the entrance of high inputs of freshwater into the lagoon and the prevailing of pollution (especially near drains). Test deformities are common and increased in the sites that exposed to pollution. The recorded modes of deformation include twisted tests, additional chamber, reduced chambers, aberrant chamber shape and size, twinning and complex deformities. Twisted or complex modes were common at the sites subjected to high levels of trace metals. This work supported the role of benthic foraminifera as an important bioindicator for the evaluation of the environmental quality of an ecosystem.

Invertebrate shells (mollusca, foraminifera) as pollution indicators, Red Sea Coast, Egypt

To assess the degree of pollution and its impact on the environment along the Red Sea Coast, the most abundant nine species of recent benthic foraminifera and three species of molluscan shells have been selected for the analysis of Fe, Mn, Zn, Cu, Pb, Ni, Co, and Cd concentrations. The selected foraminiferal species are: Textularia agglutinans, Amphispsorus hemprichii, Sorites marginalis, Peneroplis planatus, Borelis schlumbergeri, Amphistegina lessonii, Ammonia beccarii, Operculina gaimairdi, and Operculinella cumingii. The selected molluscan shells are: Lambis truncata and Strombus tricornis (gastropods) and Tridacana gigas (bivalves). The inorganic material analysis of foraminifera and molluscs from the Quseir and Safaga harbors indicates that foraminifera tests include higher concentrations of heavy metals such as Fe and Mn than molluscan shells. These results are supported by the black tests of porcelaneous foraminifera and reflect iron selectivity. The Cd and Pb concentrations in molluscan shells are high in the El Esh Area because of oil pollution at this site. The Cu, Zn, and Ni concentrations in the studied invertebrates are high at Quseir Harbor and in the El Esh Area because of the strong influence of terrigenous materials that are rich in these metals. The heavy metal contamination is mostly attributed to anthropogenic sources.

Brine formation recorded by stable isotopes of Recent benthic foraminifera in Storfjorden, Svalbard: palaeoceanographical implications

We discuss water oxygen isotopes (δ18Ow) and carbon isotopes of dissolved inorganic carbon (δ13CDIC) of brine‐enriched shelf water (BSW) from Storfjorden (southern Svalbard) in comparison to Recent benthic foraminiferal δ18Oc and δ13Cc calcified in the same water. We determined relatively high δ18Ow values of 0.15±0.03‰ VSMOW in BSW below sill depth at temperatures below −1.8 °C, and high δ18Oc values of 3.90±0.18‰ VPDB. Such high BSW δ18Ow cannot significantly deplete 18Ow contents of Arctic Ocean deep water; furthermore, such high δ18Oc cannot be distinguished from δ18Oc values of 3.82±0.12‰, calcified in warmer Arctic and Nordic seas intermediate and deeper waters. Today, in Storfjorden low benthic δ13Cc and high δ18Oc reflect the low δ13CDIC and relatively high δ18Ow of BSW. High benthic δ18Oc is in contrast to expected low δ18Oc as brine rejection is widely thought to predominantly take place in surface water diluted by meteoric water with very low δ18Ow. Low epibenthic δ13Cc values of 0.50±0.12‰ partly reflect low δ13CDIC caused by enhanced uptake of atmospheric low δ13CCO2 decreased by anthropogenic activities. An adjustment for preindustrial higher values would increase δ13Cc by about 0.6‰. Therefore, in Storfjorden brine formed before the industrial era would be characterized by both high δ13Cc as well as high δ18Oc values of benthic foraminiferal calcite. Our data may cast doubt on scenarios that explain negative excursions in benthic foraminiferal stable isotope records from the Atlantic Ocean during cold stadials in the last glacial period by enhanced brine formation in Nordic seas analogously to modern processes in Storfjorden.

FORAMINÍFEROS BENTÓNICOS RECIENTES EN LAS AGUAS PROFUNDAS DE LA CUENCA DE PANAMÁ: ECOLOGÍA Y SU POSIBLE RELACIÓN CON LAS CORRIENTES DE FONDO

The relationship between recent benthic foraminifera and bottom currents in the Panama basin (Colombian Pacific) is examined, and the main ecological variables which control the distribution of benthic foraminifera are discussed. The benthic foraminiferal study of 24 core top samples and the integration with previous reports, support the view that in upwelling areas or under high terrigenous influx, the assemblages are dominated by infaunal forms such as Uvigerina, Bolivina, Globobulimina, and Chilostomella, beside common forms such as Uvigerina peregrina Cushman and Epistominella spp., which are indicative of high productivity. In contrast, epifaunal forms such as Cibicidoides, Laticarinina, and Hoeglundina are more common on the flanks of the Cocos and Carnegie Ridges indicating a lower surface productivity and a larger content of dissolved oxygen on the sea floor. Infaunal foraminifera are dominated by Siphouvigerina proboscidea (Schwager). In addition, several proxy taxa of the intensity of deep sea currents were detected in the analyzed assemblages. From these taxa, Cibicides wuellerstorfi (Schwager) has the best proxy potential for the reconstruction of intense bottom currents in sediments from the Cocos and Carnegie Ridges for the Holocene.

Impacts of several pollutants on the distribution of recent benthic foraminifera: the southern coast of Gulf of Gabes, Tunisia.

In addition to physicochemical methods, benthic foraminifera have become an essential tool for the assessment of polluted environments. The main objectives of the present work were to study the distribution of benthic foraminifera along the coastline of Skhira and Gabes (southern coast of Gulf of Gabes) and to predict the impact of pollution on these organisms. Thirty-one samples were studied and a polluted area was delimited by chemical analysis, where heavy metal, fluoride, phosphorus, nitrogen, and COT contents are very high. Thirty-four species of benthic foraminifera were identified and their response to pollution is very remarkable, in which their distribution shows barren area, corresponding to the highly polluted area. Away from the contaminated area, the density and the diversity of these organisms increase. Statistical analyses (principal component analysis (PCA)/FA and matrix correlation) show a possible control of these pollutants on biotic indices (with negative correlation), in addition to the presence of tolerant and sensitive species to pollution. A variety of test malformations were noticed especially in Ammonia beccarii, Peneroplis planatus, Sorites variabilis, and Adelosina pulchella. Unpolluted stations were dominated by species characteristic of shallow water environments with sandy sediment such Ammonia parkinsoniana, Triloculina trigonula, Quinqueloculina agglutinans, and P. planatus.

Recent benthic foraminifera from the Caribbean continental slope and shelf off west of Colombia

A quantitative benthic foraminiferal analysis was conducted on 30 sea-floor sediment samples distributed along the continental slope and shelf in Fuerte Area (Colombian Caribbean), between 39 and 2469 m water depth.The aims of the research were to provide data on the distribution of southwestern Caribbean Recent benthic foraminifera, to estimate changes in the foraminiferal distribution related to the bathymetry and the characteristics of the substrate, to define a data-bank on distribution of recent tropical benthic foraminifera from the southwestern Caribbean, to provide reference on foraminiferal distribution that can be used in bathymetric reconstructions of ancient environments.Three different assemblages corresponding to three different environments were identified by cluster analysis. Assemblage A, characterized by variable percentages of porcellaneous, hyaline and agglutinated benthic foraminifera indicative of shelf environments. Assemblage B, dominated by calcareous hyaline foraminifera mainly composed of infaunal foraminifera corresponding to upper bathyal, marine conditions. Assemblage C, composed by agglutinated and calcareous hyaline foraminifera characteristic of normal deep-water marine environments.

Recent benthic foraminiferal assemblages from the Celtic Sea (South Western Approaches, NE Atlantic)

The faunal composition and diversity pattern of Recent benthic foraminifera from the shelf and slope of the South Western Approaches (Celtic Sea) were assessed. The sampling stations cover a depth range from 100 to 500 m. A total number of 294 species was recorded, of which 89 were found exclusively in the living fauna and 118 only in the dead assemblage, whereas 87 species were found in both assemblages. The faunal composition revealed a distinct bisection of the living fauna on the shelf. While certain distribution patterns of living dominant species were recognized along a NE-SW trending transect towards the shelf edge, the living fauna changed within small depth intervals and geographic position on the slope. Causes for these structured slope assemblages were probably along-slope currents of varying strengths, as well as variations in topography and bottom sediments. Analyses of population densities and diversity patterns determined high densities along the shelf edge and at one slope station, as well as an increasing diversity with water depth. A comparison with literature data from the same area yields distinct differences in faunal composition on the shelf and slope. The diversity was similar on the shelf, but higher at corresponding stations on the slope. We conclude that the faunal composition was highly influenced by the time and methods of sampling. In order to obtain consistent results in regional studies, all samples should be taken in a short time interval and by using the same sampling device. In addition, we depicted the influences of environmental parameters on dead faunal assemblages and their consequences for paleoenvironmental interpretations of fossil foraminiferal assemblages.

Influence of trace metals in recent benthic foraminifera distribution in the Pearl River Estuary

This work analyzed the distribution of trace metals and benthic foraminifera in the Pearl River Estuary and studied the influence of environmental parameters (i.e., trace metals, organic matter and sediment grain size) on the total (living plus dead) benthic foraminiferal assemblages. The results indicate that the distribution patterns of Co, Cr, Cu, Ni, Pb and Zn are strongly related to the behavior of the sedimentary clay fraction (kaolinite and illite) and are dispersed with sedimentary material, whereas Ba, Sr, V and Zr follow different trends. The study area is moderately to severely polluted with Co, Cr, Cu, Ni, Pb and Zn, and maximum values were found in the upstream and on the western side of the estuary, where the lowest levels of H(S), Fisher alpha index and number of species are situated. Analyses of species abundance and community diversity, as well as the subsequent canonical redundancy analysis, were conducted to reveal the relationship between the foraminifera data and environmental parameters. Two assemblages were established by cluster analysis and were distributed in relation to bathymetry. The distribution of foraminiferal assemblages was mainly determined by Cu, Zn and Pb; while sand may exert an influence on particular species. Ammonia tepida, Haplophragmoides canariensis and Elphidium nakanokawaense are tolerant to the metal enrichment; while the abundances of the other species decline and are prejudiced. This study indicates that benthic foraminifera can be used as a bio-indicator of trace metal pollutants in the Pearl River Estuary and the results promote a better understanding of the response of benthic foraminifera to human-induced pollution in estuaries. (C) 2014 Elsevier B.V. All rights reserved.

Impact evaluation of the industrial activities in the Bay of Bakar (Adriatic Sea, Croatia): Recent benthic foraminifera and heavy metals

The Bay of Bakar is one of the most heavily polluted bays at the Eastern Adriatic. Three major industrial companies potentially endanger the bay. The concentration of major, minor and trace elements in surface sediments from thirteen stations was discussed in relation to the sediment type and foraminiferal assemblages. The distribution of major elements in the bay is influenced by geological nature of surroundings. Heavy metal distribution depends on pollution sources and on amount of mud fraction: fine-grained sediments are enriched by them in comparison with coarse-grained ones. Different sediment quality criteria complicate the pollution assessment in the bay. Heavy metal concentrations generally fall into allowed depositional values for marine environments; only area in front of the coke plant and the City of Bakar harbor is heavily polluted. Stress-tolerant foraminiferal species dominate at stations with higher concentrations of heavy metals and coarse-grained sediments consist of larger number of epifaunal taxa.

Recent benthic foraminifera from Twofold Bay, Eden NSW: community structure, biotopes and distribution controls

Twofold Bay lies at the confluence of two oceanic boundaries, the near end of the East Australian Current and waters from the Southern Ocean. The Bay is NSW's largest commercial fishing port and has been home to much anthropogenic activity, ranging from whaling, mussel farming, timber export, large boat traffic, Australian Navy activities and recreational fishing. We investigated the sediments and associated foraminifer fauna in the bay and identified four different sedimentological associations linked to local currents and water depths and three foraminiferal associations, with live to dead specimen ratios established for each sample site. Three principal biotopes have been identified using cluster analysis of foraminiferal assemblages, with each biotope characterised by a specific faunal population and substrate type: (1) Inner Bay Biotope, characterised by Elphidium aff. advenum and predominantly very fine–fine sand substrates (63–250 μm); (2) Outer Bay Biotope characterised by Discorbis dimidiatus and medium–coarse sand substrates (250–1000 μm); (3) Harbour Biotope characterised by the widespread species Elphidium advenum macelliforme and bimodal sediments with very fine–coarse silts (2–63 μm) and medium sands (250–500 μm). Substrate type and energy intensity are proposed as limiting factors to foraminiferal distribution and composition. In addition, a short (21 cm long) core obtained from near the entrance of Eden Harbour has been examined in terms of foraminifer assemblages established for the bay. Microfaunal composition shifts clearly correlate with sediment colour changes, while foraminiferal and sedimentary data indicate strong concordant physical and ecological patterns. However, radiocarbon dates from various levels in the core point to sediment disturbance, contradicting this hypothesis. Hence, the dating of the sequence remains problematic.