Cribroelphidium Excavatum Research Articles

The Later Holocene Foraminifera of Liverpool Bay (Bae Lerpwl), British Isles: Morphospecies and Community Level Patterns

Abstract Two cores were studied from Liverpool Bay (∼40 m water depth). The lowest 80 cm of ISLF13 (290 cm long) comprised clay, gypsum and pyritised foraminifera (Surface Layer 2 Member, gypsiferous lithofacies GLF) from a tidal flat dominated by Cribroelphidium excavatum. Perturbation Detection Analysis (PDA) found two ISLF13 GLF abundance biozones (ABs) with assemblages in stasis. ISLF16 (80 cm long) and between 30–202 cm in ISLF13 were open marine, sandy with gastropods and bivalves (Surface Layer 1 Member, shelly sand lithofacies SSLF). Assemblages in the SSLF sections differed, despite their proximity. That in ISLF13 comprised dominant C. excavatum with lesser Ammonia batava, Asterigerinata mamilla, Cibicides refulgens and Bulimina elongata. PDA identified two ISLF13 SSLF ABs, both in growth stages. The ISLF16 assemblage was co-dominated by C. excavatum, A. mamilla and A. batava from a single AB in stasis. This difference might reflect sorting. Asterigerinata murraynhaynesi n. sp. is described.

Distribution of Foraminiferal Assemblages in Contemporary Bottom Sediments of Qua-Iboe River Estuary, Southeast Nigeria

Abstract Qua-Iboe River estuary, Southeast Nigeria, was studied to determine the relationship between foraminiferal distribution and bottom water physicochemical parameters including salinity, temperature, depth, dissolved oxygen, pH, tidal energy, and sediment. Fifty-five bottom sediment samples from geo-referenced stations were collected at water depths of 0–10 m across the channel. Ten species of foraminifera were identified in the estuary. Q-mode cluster analysis resulted in two biotopes (1 and 2), each representing distinct sub-environments. Biotope 1 included two sub-groups namely, 1a and 1b. Biotope 1a represents the upper estuary environment and is distinguished by the non-recovery of foraminifera. It has a maximum water depth of 8.3 m and occurs in freshwater conditions (0 ppt) with slightly acidic to neutral pH and fine- to medium-grained sands. Biotope 1b is found in the mid-estuarine environment and has a maximum water depth of 4 m. It is distinguished by an abundance of Arenoparrella mexicana. Biotope 2 occurs within the subtidal lower estuarine environment with a maximum water depth of 4 m. It is characterized by slightly acidic to slightly alkaline (pH = 6–8), brackish to marine waters, with fine to very fine-grained sands. Foraminiferal species commonly found in this biotope include Ammonia beccarii, Pseudononion japonicum, and Cribroelphidium excavatum. As salinity increased seawards, agglutinated taxa were gradually replaced by calcareous species. Foraminiferal assemblages in bottom sediments are strongly influenced by salinity.

Benthic Foraminiferal Response to Trace Elements in a Tropical Mesotidal Brazilian Estuary

Living benthic foraminifera have been widely used as ecological indicators in coastal ecosystems. There is, however, a lack of studies on their response to trace element pollution in tropical estuarine systems. Here we analyze the living assemblages of benthic foraminifera, collected in 2016, in the Cachoeira River Estuary (CRE) in northeastern Brazil, to understand their response to natural and anthropogenic stressors, including trace element pollution. Some species were good bioindicators of specific environmental conditions, such as the agglutinant Paratrochammina clossi which preferred mangrove areas and anoxic conditions. In addition, the calcareous Ammonia tepida and Cribroelphidium excavatum, dominant within the whole system disregarding organic or trace element pollution, seem to resist even in the areas most polluted by trace elements. Interestingly, C. excavatum showed a particular positive relationship with trace element pollution (specifically by Cu and Pb), outnumbering the opportunistic A. tepida in the areas with higher pollution of these metals. However, for other species, it is still difficult to constrain to which parameters they respond (i.e., Haynesina germanica and Elphidium gunteri, which in the present study seem to respond to natural conditions, whereas in the literature they are regarded as indicators of trace element and organic pollution, respectively). Therefore, our findings shed light on the response of benthic foraminiferal species in a highly polluted and highly mixed tropical estuarine system and highlight the need to understand the complexity of these environments when applying foraminiferal biological indexes to avoid imprecise conclusions.

Palaeoenvironmental changes based on foraminifera during the late Holocene at the Beagle Channel, Argentina.

A foraminiferal faunal study was carried out in a Holocene marine section from Arroyo Baliza, located on the northwest coast of the Beagle Channel, to contribute to the knowledge of the palaeoenvironmental conditions during the marine Holocene event. Foraminiferal assemblage was represented by 32 species distributed among 21 genera. The assemblage was dominated by Elphidium macellum (Fichtel & Moll) Elphidium alvarezianum (d'Orbigny), Cribroelphidium excavatum (Terquem) and Buccella peruviana (d'Orbigny), accompanied by Cibicides fletcheri Galloway & Wissler and Cibicidoides dispars (d'Orbigny) in low proportion. The predominance of Peridiniales dinocysts in the marine palynomorphs assemblage, suggested inner neritic conditions with cooler and more nutrient-rich waters. The distribution of the foraminiferal species was variable throughout the section indicating palaeoenvironmental changes in Arroyo Baliza between 3499-2595 cal yr BP. A gradual passage from high energy, cold and well-oxygenated marine waters towards a shallower environment with low energy and low to moderate salinity of the waters were linked to the regressive phase. This study complements and supports the previous palynological data from this section, which reflects an increase in number and diversity of dinocyst species indicating marine environmental conditions during the late Holocene as it exists today in the Beagle Channel.

Contemporary distribution of benthic foraminiferal assemblages in coastal wetlands of south-eastern Australia

Benthic foraminifera identified from the upper intertidal zone of coastal mangrove and saltmarsh wetlands of south-eastern Australia exhibit spatial zonation that varies with elevation and corresponds to position in the tidal frame. This study describes relationships between benthic foraminiferal assemblages and environmental variables, such as wetland elevation, pore-water salinity, substrate organic matter content and sediment grainsize. Agglutinated taxa dominated higher in the tidal frame, whereas calcareous taxa increased in both relative abundance and diversity lower in the tidal frame. Species composition varied within and between study sites, reflecting local differences in other environmental variables. Three major spatial clusters were identified in the upper intertidal zone from a dataset consisting of 111 contemporary samples: a high-to mid-elevation assemblage consisting of differing abundances of Entzia macrescens and Trochammina inflata; a mid-elevation assemblage comprised of Arenoparrella mexicana in association with Trochammina inflata and Quinqueloculina seminula; and mid-to low-elevation assemblage characterised by Cribroelphidium excavatum, Quinqueloculina seminula, Ammobaculites spp. and Miliammina fusca. Multivariate analysis correlated foraminiferal assemblages with environmental variables showing that foraminiferal distribution in the region is constrained primarily by wetland elevation, but also by pore-water salinity. Foraminiferal assemblages derived from cluster analysis correlated with vegetation zones, implying that both foraminifera and vegetation are influenced by elevation and salinity. This paper seeks to demonstrate that the consistency in spatial zonation of assemblages provides greater confidence that contemporary distribution of foraminiferal assemblages can assist with the interpretation of past depositional conditions and palaeo-environmental reconstructions, providing insights into the evolution of coastal wetlands of south-eastern Australia over the Holocene.

Ecological quality status of the NE sector of the Guanabara Bay (Brazil): A case of living benthic foraminiferal resilience

The ecological quality status of the NE region of the Guanabara Bay (SE Brazil), one of the most important Brazilian embayments, is evaluated. For this purpose, sediment samples from in the inner of the Guanabara Bay (GB) were collected and analyzed (grain-size, mineralogy, geochemistry and living foraminifera). In this study, it is hypothesized that the potentially toxic elements (PTEs) concentrations, in solution and associated with organic matter (OMPTEs, potential nutrient source), may represent two potential pathways to impact benthic foraminifers. A multiproxy approach applied to complex statistical analyses and ecological indexes shows that the study area is, in general, eutrophic (with high organic matter and low oxygen content), polluted by PTEs and oil. As a consequence, foraminifera are not abundant and their assemblages are poorly diversified and dominated by some stress-tolerant species (i.e., Ammonia tepida, Quinqueloculina seminula, Cribroelphidium excavatum). The results allow us to identify a set of species sensitive to eutrophication and OMPTEs. Factors such as the increase of organic matter contents and OMPTEs and, in particular of Zn, Cd and Pb, the oxygen depletion and the presence of oil, altogether contribute to a marked reduction in the abundance and diversity of foraminifera. Ammonia-Elphidium Index and the Foram Stress Index confirm that the NE zone of GB is, in general, “heavily polluted”, with “poor ecological quality status” and experiences suboxic to anoxic conditions. In light of it, special attention from public authorities and policymakers is required in order to take immediate actions to enable its environmental recovery.

Multidisciplinary study to monitor consequences of pollution on intertidal benthic ecosystems (Hauts de France, English Channel, France): Comparison with natural areas

The intertidal areas of the Hauts-de-France (English Channel – France) stand out for the occurrence of fragile ecosystems that are exposed to natural and human–induced stress. Over the last two centuries, the northern part of this region has experienced a strong human pressure, with the settlement of numerous activities (i.e., metallurgic factories, harbors, embankments). On the contrary, the southern part includes mostly natural areas. The whole region is influenced by a macrotidal regime. A multidisciplinary approach based on sedimentological (grain-size), geochemical (trace metals, biomarkers) and biological (foraminifera) proxies was used to unravel the contrasting environmental conditions in the Hauts-de-France. Three foraminiferal-types communities, which reflect different ecological characteristics at regional scale, were identified: 1) estuarine macrotidal assemblages (Haynesina germanica associated to Elphidiidae) in low impacted estuaries; 2) industrial-perturbed assemblages (H. germanica and Cribroelphidium excavatum) in harbor areas; and 3) infaunal-dominant assemblages (Bolivina variabilis and B. pseudoplicata) in embankment areas. The outcomes of this study show that a multiproxy procedure needs to be adopted for properly characterizing intertidal ecosystems, where human impacts and natural stresses overlap and are hard to disentangle.

Sediment Geochemistry and Benthic Foraminiferal Response to Fish Farming after Conversion from a Red Laver (Seaweed) Farm

Jeong, D.U.; Lee, Y.G.; Kang, J.; Woo, H.J., and Choi, Y.H., 2020. Sediment geochemistry and benthic foraminiferal response to fish farming after conversion from a red laver (seaweed) farm. Journal of Coastal Research, 36(3), 559–574. Coconut Creek (Florida), ISSN 0749-0208.To understand the effects of biodeposits discharged from a fish farm (which was previously a red laver farm) on geochemistry of the sediment and benthic ecology, trace metals and element analyses, 210Pb dating, and benthic foraminiferal analyses were conducted on sediment cores collected below the fish farm cages. Sediment core sampling was also carried out at a control plot (160 m away) to understand the spreading of biodeposits. The geochemical effect of fish farming is pronounced. There was an increase in silt content and sedimentation fluxes of Znex (Zn in excess fractions), Cuex, Asex, and TPex (total phosphorus in excess fractions) after red laver farming. The silt content increased from 45.01% to 50.07%, with a sediment accumulation rate of ∼0.61 cm/y, on average. TPex, with 0.15% ± 0.06% on average, showed that the fish farming effects increased by 0.22% ± 0.07%. Znex, Cuex, Cdex, and Asex showed a positive relationship with TPex increase: 19.92 ± 1.79, 10.23 ± 3.99, 0.57 ± 0.19, and 0.92 ± 0.04 µg/cm2/y, respectively. The high sedimentation fluxes of Znex and Asex in the control plot may signify an expansion of influence of the fish farm by tidal currents. Seven benthic foraminifera appeared during the fish and red laver farming periods, with the dominant species being Cribroelphidium excavatum; however, they were characterized by a high similarity index of 88.1% and very low frequency of abundance, indicating bad habitat conditions. Among them, the C. excavatum–Ammonia beccarii–Ammonia ketienziensis–Cribroelphidium subarcticum assemblage ranged from 21 cm depth to the uppermost layer, characterized by increases in A. beccarii. This increase may have been caused by the accumulation of organic matter discharged from the fish farm after red laver farming, rather than from an increase in the trace metals. A. beccarii may be a species tolerant to fish farming.

Seasonal Dynamics of Benthic Foraminiferal Biocoenosis in the Tropical Saquarema Lagoonal System (Brazil)

This study investigates and compares the seasonal variations during winter and summer of living benthic foraminiferal assemblages in the Saquarema Lagoon System (SLS) located in a tropical coastal region of SE Brazil. The physicochemical parameters in the SLS presented strong differences between both seasons; however, they remained quite homogeneous in winter and exhibited great oscillations in summer. In the study area, 29 and 19 living foraminiferal species were identified in summer and winter, respectively. Ammonia tepida was the dominant species in both seasons followed by Ammonia parkinsoniana and Cribroelphidium excavatum. The detrended correspondence analysis showed that in the SLS: the calcareous species, such as Adelosina carinatastriata, Bulimina patagonica, and Miliolinella antartica were mostly influenced by high dissolved oxygen contents and low temperature, whereas the agglutinated foraminiferal species were indicators of the most confined lagoonal areas, under the lowest pH and salinity values. The results of this work evidence that the seasonal variation in the SLS might play a more important role in the benthic foraminiferal assemblages’ distribution than the anthropogenic impacts and shows the importance of seasonal studies for coastal biomonitoring programs.

Living and dead Foraminifera as bioindicators in Saquarema Lagoon System, Brazil

The understanding of the differences between living (L) and dead (D) benthic foraminiferal assemblages and all the factors that might lead their distribution should be a key to characterize the environmental and paleoenvironmental changes accurately. Population dynamics and dissimilarities of biological nature (the differences in turnover rate and seasonal alterations in standing stock) can cause significant divergences between the L and D foraminiferal assemblages. This study compares L and D foraminifera to evaluate the sediment quality of the Brazilian Saquarema Lagoon System (SLS) using biogeochemical proxies and predict how coastal ecosystems are responding to the combined effects of eutrophication and pollution pressure and areas where the paleoenvironmental studies can be performed. The SLS is a transitional environment where total organic carbon, proteins, and dissolved oxygen are the main factors controlling the distribution of foraminiferal assemblage. The high values of biopolymers (carbohydrates, lipids, and proteins) in SLS indicate a very impacted environment with long water residence time. The low values of species richness, Shannon-Weaver diversity, and evenness for both L and D foraminiferal assemblages are a consequence of fluctuating conditions in the SLS. Due to low salinities, agglutinated species and Quinqueloculina seminula can occur in the most confined areas, and Ammonia parkinsoniana , Cribroelphidium excavatum , Cribroelphidium poeyanum , and Elphidium gunteri characterized the area with the highest marine influence. Although in most of the SLS the taphonomic processes modified the original assemblage, in some regions the thanatocoenosis corresponds to the biocenosis. These areas can be considered the most suitable for future paleoenvironmental and paleoclimatic studies.

Benthic foraminifera and trace metal distribution: a case study from the Burullus Lagoon, Egypt

Benthic foraminifera are widely used to detect the health of their habitat, where they are very sensitive to even slight variations in the ecosystem. Therefore, the main objectives of this study are to examine the benthic foraminiferal assemblages in the sediments of Burullus Lagoon, evaluate the pollution levels and deduce the impact of trace metals on foraminifera. The continuous discharge of trace metals from agricultural, industrial and domestic sources into the lagoon may lead to a severe environmental problem. The concentrations of Mn, Cu, Cd, Zn and Pb within the sediments were measured. Recently, the assessment of contamination is principally based on the contamination indices which provide fast and simple quantitative values on the degree of pollution in a given aquatic environment. Thus, some indices, including the contamination factor, the degree of contamination, pollution load index, geoaccumulation index, ecological risk factor and potential ecological risk index are applied in this investigation. Based on the contamination factors, the sediments are very highly contaminated with Cd, considerably to very highly contaminated with Cu and Zn, moderately contaminated with Mn, low to moderately contaminated with Pb. All sites display very high values for the degree of contamination. Moreover, the values of the pollution load index are higher than 1, indicating that the lagoon is polluted. Depending on the geoaccumulation index, the contaminants are arranged as follows Cd>Zn>Cu>Mn>Pb. It is clear that Cd is the main contributor to the ecological risk factor in Burullus Lagoon. Concerning the richness of the foraminiferal assemblages, it fluctuates between 1–5 species per sample. Because of its higher tolerance to extreme conditions (changes in salinity and pollution), Ammonia tepida is the most abundant species. The occurrence of rare living individuals (25) is restricted only to sites close to El-Boughaz Inlet where higher salinity and lower levels of pollution are recorded. The same trend of distribution is shown by Cribroelphidium excavatum and miliolids, where they occur at sites with higher salinities. The occurrence of test deformities in all the studied sites may be related to the response of benthic foraminifera to trace metal. The forms of deformation include spiroconvex, reduced chambers, twisted tests, twinning, additional chamber and complex forms. The deformation depends on the nature of pollutants. Twinning and reduced chambers are the most dominant forms in areas close to the agricultural drainage (southern drains), while complex forms are abundant in areas close to industrial drainage (El-Gharbia drain). Thus, salinity and pollution may be the most regulatory factors controlling the distribution of foraminifera. This investigation confirmed the role of benthic foraminifera as a good ecological indicator in Burullus Lagoon.

Maximum flood area during MIS 1 in the Almenara marshland (Western Mediterranean): Benthic foraminifera and sedimentary record

The sedimentological and micropaleontological analysis of three mechanical cores in the marshland of Almenara (Valencian Community, Spain) has allowed the reconstruction of the Holocene evolution of this wetland. The cold and dry 8.2-ka event might be represented in Almenara by a massive carbonate precipitation bed, upon which mid- and late-Holocene sediments were subsequently deposited. The direct influence of sea-level changes has been recorded in the two cores (S-4 and S-5) located near the marsh barrier, at 400–450 m from the current coastline. The maximum flood area during MIS 1 (last 11,600 years) is represented in these cores by sediments indicative of different littoral subenvironments (shoreface, foreshore, backshore). These sediments contain typically littoral marine foraminiferal species such as Ammonia beccarii, Rosalina globularis, Asterigerinata mamilla, Adelosina longirostra, Cibicidoides lobatulus, Elphidium macellum, and Bolivina pseudoplicata. The base of these littoral sedimentary materials has been dated as 5480 and 5580 cal. yr BP. At this moment, the inner area (core S-7) was occupied by a restricted oligohaline marsh subject to water-table fluctuations and with scarce individuals of brackish water foraminifera, such as Ammonia tepida, Haynesina germanica, or Cribroelphidium excavatum, that in more recent times (since at least 1700 cal. yr BP) gradually evolved to a palustrine area.

Initial dispersal (1986-1987) of the invasive foraminifera Trochammina hadai Uchio in San Francisco Bay, California, USA

A time series of three closely-spaced data sets are used to track the early expansion of the invasive Japanese benthic foraminifera Trochammina hadai in the southern portion of San Francisco Bay known as South Bay. The species initially appeared in 1983, comprising only 1.5% of the assemblage in one of four samples that were dominated by the native species Ammonia tepida and Cribroelphidium excavatum (means = 60.2% and 33.8%, respectively). By 1986, census counts and R- andQ-mode cluster analyses document the explosive growth of the invasive as T. hadai now dominates the assemblage (mean = 42.7%;max = 88.7%)with associated declines in abundance of A. tepida (by greater than one-half; mean = 26.8%) and C. excavatum (by greater than one-third; mean = 20.6%). The invasive continued to dominant the assemblage in 1987, spreading even further to the north and south in South Bay, although its average abundance dropped slightly (~2%) as did those of A. tepida (~3%) and C. excavatum (0.4%). A rare increase in abundance of Elphidiella hannai and the appearance of numerous coastalmarine species in the central portion of the bay are thought to be the result of an incursion ofmarine waters into South Bay due to the prevalent drought conditions in 1987. Clearly, the rapid decline in abundance of the formerly dominant species A. tepida and C. excavatum in South Bay from 1983 to 1986 that continued into 1987 suggests the introduction of T. hadai in the bay severely impacted the native population.

Palaeoceanographic and environmental changes in the eastern Fram Strait during the last 14,000 years based on benthic and planktonic foraminifera

Abstract Benthic and planktonic foraminifera, stable isotopes and other geochemical and sedimentological parameters have been investigated in a sediment core from Vestnesa Ridge (79°N, NW Svalbard margin, 1300 m water depth) in order to reconstruct the palaeoceanographic and palaeoenvironmental evolution of the eastern Fram Strait during the last 14,000 years. Our multiproxy data and, in particular, our high-resolution benthic foraminiferal record allow a detailed reconstruction of the intermediate water flow in the eastern Fram Strait. During the Bolling-Allerod warm interstadials the high proportion of the benthic Atlantic species Cassidulina neoteretis suggests the presence of chilled Atlantic-derived water at the bottom of the Vestnesa Ridge, while the dominance of the polar planktonic species Neogloboquadrina pachyderma (s) indicates cold polar surface conditions. During the Younger Dryas cold stadial the inflow of Atlantic-derived water was weakened and of lower temperature compared to the previous interval, as suggested by the increase in the glacio-marine indicator Cassidulina reniforme and the lower percentages of C. neoteretis. After 11,000 cal yr BP the abrupt increase in relative abundance of the benthic species Cibicides wuellerstorfi and Oridorsalis umbonatus, indicates a shift to interglacial conditions with deep convection and generation of cold intermediate water. Warm surface water conditions were finally established at about 10,300 cal yr BP, when Turborotalita quinqueloba became the dominant planktonic species. Generally warmer conditions than today were recorded in the middle Holocene, with a mild cooling at about 8200 cal yr BP and a more pronounced cool interval with an abrupt decrease in T. quinqueloba between 7000 and 6200 cal yr BP. Cold climatic conditions were established around 4100 cal yr BP when N. pachyderma (s) became again the dominant species and the polar benthic species Cribroelphidium excavatum appeared.

Good News and Bad News in Two Highly Industrialized Puget Sound, Washington (u.s.a.) Embayments

AbstractIn this study, an offshoot of studies undertaken by the Washington State Department of Ecology (WDOE), the density and diversity of foraminiferal assemblages in Commencement and Elliott bays, two heavily industrialized embayments in Puget Sound, Washington (U.S.A) were compared and correlated with concentrations of metal pollutants and total polycyclic aromatic hydrocarbons (PAH). Samples used in this study were collected by the WDOE between 1998 and 2014, allowing comparison over a temporal range encompassing the beginnings of environmental remediation in both bays. The composition of the foraminiferal assemblages is typical of polluted estuaries globally, with the major taxa being Elphidiella hannai, Cribroelphidium excavatum, Bucella frigida and Eggerella advena. Foraminiferal density and diversity showed negative correlations with pollutants, however, these correlations were significant for only a few pollutants, and trends could not be attributed to any single one. Both embayments showed increasing diversity over time, and both had high proportions of calcareous tests that displayed signs of dissolution, indicating corrosive conditions in the water. In Elliott Bay the percentage of partially dissolved tests increased over time, suggesting remediation efforts have not been successful in all areas.

Foraminíferos e Tecamebas Bentônicos do Estuário do Rio Godineau, Golfo de Paria, Ilha de Trinidad

In the Godineau River Estuary, located in Trinidad Island (off the northeast coast of Venezuela), were found 114 taxa of foraminifera and 17 of thecamoebians in the dead fauna. Most of the identified foraminiferal species were rare because they were transported from the Gulf of Paria to this estuary. The autochthonous foraminiferal assemblage was represented by several tropical estuarine species such as Ammonia tepida, Ammotium salsum, Arenoparrella mexicana, Cribroelphidium excavatum, Ammonia parkinsoniana, Haplophragmoides wilberti, Miliammina fusca and Ammotium cassis. The thecamoebians assemblages, found in the inner part of this estuary, were dominated by Cyclopyxis spp., Centropyxis spp., Difflugia corona and Difflugia urceolata. The relative abundance of the main species of foraminifera and thecamoebians were analyzed through Q-mode and R-mode cluster analyses. Statistical results revealed the presence of three different environments in the Godineau River Estuary related to different hydrodynamic conditions and more or less oceanic or fluvial influence. The first sector represents the most confined region of the estuary and was mainly composed by agglutinated foraminifera together with thecamoebians. The second sector was located in the middle part of the estuary and was associated with the presence of brackish waters. The third sector denotes the outermost part of the estuary characterized by the greatest hydrodynamic activity and highest oceanic influence within the estuary. This sector was marked by the occurrence of a large number typical-marine foraminifera species.

Foraminíferos e Tecamebas Bentônicos do Estuário do Rio Godineau, Golfo de Paria, Ilha de Trinidad

In the Godineau River Estuary, located in Trinidad Island (off the northeast coast of Venezuela), were found 114 taxa of foraminifera and 17 of thecamoebians in the dead fauna. Most of the identified foraminiferal species were rare because they were transported from the Gulf of Paria to this estuary. The autochthonous foraminiferal assemblage was represented by several tropical estuarine species such as Ammonia tepida, Ammotium salsum, Arenoparrella mexicana, Cribroelphidium excavatum, Ammonia parkinsoniana, Haplophragmoides wilberti, Miliammina fusca and Ammotium cassis. The thecamoebians assemblages, found in the inner part of this estuary, were dominated by Cyclopyxis spp., Centropyxis spp., Difflugia corona and Difflugia urceolata. The relative abundance of the main species of foraminifera and thecamoebians were analyzed through Q-mode and R-mode cluster analyses. Statistical results revealed the presence of three different environments in the Godineau River Estuary related to different hydrodynamic conditions and more or less oceanic or fluvial influence. The first sector represents the most confined region of the estuary and was mainly composed by agglutinated foraminifera together with thecamoebians. The second sector was located in the middle part of the estuary and was associated with the presence of brackish waters. The third sector denotes the outermost part of the estuary characterized by the greatest hydrodynamic activity and highest oceanic influence within the estuary. This sector was marked by the occurrence of a large number typical-marine foraminifera species.

Spatial distribution of living (Rose Bengal stained) benthic foraminifera in the Loire estuary (western France)

Ninety-seven surface sediment samples were collected in September 2012 from intertidal and subtidal areas along the Loire estuary (western France). The main objective of this work is to study the spatial distributional patterns of living benthic foraminifera and their link to the environmental parameters (distance to sea, elevation, grain size, total organic carbon, trace metals, sedimentary carbonates, and polycyclic aromatic hydrocarbons) in the Loire estuary. Foraminiferal analysis was also extended to the dead assemblages in thirty-three surface samples from the lower inner estuary. The highest absolute densities of living benthic foraminifera are found in the lower inner estuary within the polyhaline domain. This is attributed to the presence of mudflats with abundant food source, i.e. microphytobenthos. The low densities found in the outer estuary (euhaline domain) are attributed partly to the sandy nature of the sediments and the food source inhabiting this substrate. The near absence of foraminifera in the inner estuary (mesohaline and polyhaline domains) is inferred to the physical disturbance resulting from the regular dredging of the navigation channel. The living assemblages are dominated by three typical estuarine species: Ammonia tepida and Haynesina germanica in the intertidal mudflats of the lower inner estuary and Cribroelphidium excavatum in the sandy subtidal sediments of the lower inner and outer estuary. In the Loire estuary, H. germanica has an unusual intermediate geographical distribution along the estuary between A. tepida and C. excavatum while in most temperate estuaries this species is present upstream in the mesohaline domain. This is most likely the result of the regular dredging of the navigation channel damaging its natural habitat. This might be also the explanation for the total absence of agglutinated species usually dominating the oligohaline domain. The canonical correspondence analysis shows that elevation (and its link to time of emersion), distance to sea (and its correspondence with salinity), and organic carbon content appear to be the primary drivers of foraminiferal distribution. The present study provides for the first time ecological and distribution patterns of living benthic foraminiferal communities in the Loire estuary. This baseline knowledge is necessary for the future studies focusing on the use of benthic foraminifera as bio-indicators in the Loire estuary and in transitional environments in general.

THE DEVIL LIES IN DETAILS: NEW INSIGHTS INTO THE BEHAVIOURAL ECOLOGY OF INTERTIDAL FORAMINIFERA

The motion behaviour of three species of intertidal foraminifera, Ammonia tepida , Cribroelphidium excavatum and Haynesina germanica , was investigated continuously in the laboratory. We first infer the presence of geotactic and phototactic responses. Significant geotactic responses were observed for all three species; A. tepida was found to be negatively geotactic while C. excavatum and H. germanica showed positive geotaxis. In contrast, no response to light was ever observed. The detailed nature of motility, investigated in terms of both geometric and stochastic complexity of their motion behaviour, was consistently characterised by a strong inter-specific, inter-individual and intra-individual variability. Specifically, A. tepida and H. germanica were characterised by an intensive search behaviour (they explore their environment slowly with straighter trajectories), while C. excavatum adopted an extensive search strategy (it moves more rapidly with more convoluted trajectories). These observations are discussed in the specific context of the ecology of these species. We see their responses as adaptive advantages in spatially and temporally complex environments prone to a range of both predictable and unpredictable rapid stressors. From a methodological point of view, we showed that previous methods used to infer foraminiferal motion behaviour are likely to have systematically underestimated their speed and distance travelled by a factor ranging from 2 to 80.

High Benthic Foraminiferal Diversity in Polluted Busan North Port (Korea)

Surface sediments were collected from Busan North Port (southern coast of Korea) and the outer port area (OPA) in February and August 2009 to ascertain the distribution of benthic foraminifera and assess controlling environmental factors. Ninety-eight species (81 calcareous and 17 agglutinated), 40 of which had live representatives, were identified. Busan North Port can be divided into distinctive regions according to different depositional environments and to the degree of influence from pollution sources, such as nearby streams and industrial facilities around the inside north port (INP) and outside north port (ONP). The OPA is characterized by inner continental-shelf environments. These areal distinctions corresponded well to cluster- and principal component-analysis results based on foraminiferal-assemblage and heavy-metal data. The degree of organic enrichment and heavy-metal concentration in the sediments were major factors explaining the distributions of the foraminiferal assemblage. The low abundance of benthic foraminifera in the INP compared to the OPA seems to be directly related to heavymetal toxicity caused by high Cu, Zn, and Pb concentrations. The dominant occurrence of pioneer species Cribroelphidium excavatum and Trochammina hadai appears to indicate the adverse effects of heavy metals and high levels of organic matter on benthic foraminiferal distribution in the INP. Species diversity, however, was unusually high in Busan North Port across all pollution levels, and can possibly be explained in two ways. Short water-residence time in the inner port and maintenance of high salinity through active seawater exchange may reduce the effects of heavy metals and possibly make the area hospitable to a variety of species. High diversity may also be attributed to “rare short-lived” species that favor unstable conditions. The response of the benthic foraminiferal community to the unstable environment seems to be a succession of these “rare short-lived” species rather than a predominance of a few opportunistic ones. The uncoupling of species diversity and pollution level observed in Busan North Port might not be uncommon, and caution should be exercised when benthic foraminiferal diversity is used as an index of relative environmental health. Presence of indicator species and/or size distribution in the foraminiferal assemblage should be considered as well as species diversity to correlate the community structure with environmental change and pollution level.