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Recent New Zealand shallow-water benthic foraminifera: Taxonomy, ecologic distribution, biogeography, and use in paleoenvironmental assessment
Abstract
ABSTRACT
Ecologic distribution of brackish water foraminifera
Census data on 89 species of benthic foraminiferal tests from 131 samples from brackish water environments throughout New Zealand are analysed by cluster and correspondence analyses. Ten brackish water faunal associations are recognised. When mapped in study areas they can be seen to inhabit distinct estuarine and tidal inlet environments. The associations are characterised by Trochamminita salsa, Haplophragmoides wilberti, Trochammina inflata, Jadammina macrescens, Miliammina fusca, Elphidium excavatum and Ammonia parkinsoniana, on their own or in combinations. Canonical correspondence analysis indicates that the factors most influential in determining the faunal distribution in brackish environments are, in descending order of importance: salinity, tidal exposure, and presence of intertidal vegetation. Associations characterised by agglutinated species occur in the more extreme brackish water environments - in the least saline environments and also above mean high water.
Ecologic distribution of normal marine salinity foraminifera
Census data on 327 species of benthic foraminiferal tests from 197 samples from shallow water (<100 m), normal marine environments around New Zealand are analysed by cluster and correspondence analyses. Eighteen faunal associations inhabiting distinct coastal environments are recognised. The associations are characterised by various combinations of species of Elphidium, Haynesina, Pileolina, Rosalina, Gaudryina, Notorotalia, Planoglabratella, Quinqueloculina, Cibicides, Zeaflorilus, Virgulopsis, Patellinella, Nonionellina, Trifarina, Bulimina and Cassidulina. Canonical correspondence analysis indicates that the following factors in decreasing order of importance are most influential in determining the faunal distribution in normal marine environments: factors linked to depth, factors linked to wave and current energy, factors linked to biogeography, bottom water oxygen concentrations and substrate type.
Taxonomy
419 species are listed from shallow water (<100 m) around New Zealand. The 233 most common or distinctive species are fully illustrated and their diagnostic features outlined. Four new species are described: Glabratellina kermadecensis n.sp., Neoconorbina cavalliensis n.sp., Pileolina gracei n.sp. and Notorotalia hornibrooki n.sp..
Frequency of species occurrence
To assess species frequency, species duration and biogeography, we used a data set containing the presence/absence records of 353 species in 50 composite shallow water localities from around the New Zealand region. The frequency of species occurrence follows a log series curve with 35% of the species occurring rarely (1-2 localities) and 20% occurring commonly (>16 localities). Rotaliinid species have the greatest frequency of occurrence (35% are common), whereas lageninids and textulariinids have the greatest number of rare species (44%, 55%). Unlike reported North American results, there appears to be no significant difference in the percentage of endemic or cosmopolitan species that are rare or common.
Species duration
128 Recent benthic species (36%) have a recorded New Zealand fossil record (50% of rotaliinids, <35% of other suborders). One species first appears in each of the late Cretaceous and Paleocene, 22 in Eocene, 25 in Oligocene, 67 in Miocene, 14 in Pliocene, 4 in Pleistocene, with major influxes in the latest Eocene-early Oligocene, and early Miocene (31 species each). Species with a fossil record have a mean partial species duration of 21 m.yrs. Deeper water species (live dominantly >100 m) have a longer mean duration (24 m.yrs.), than dominantly shallow species (20 m.yrs.) or brackish species (9 m.yrs.).
Commonly occurring species have a far greater percentage with a fossil record (55%) than rarely occurring species (19%). Contrary to findings elsewhere, the rarely occurring species with a fossil record have a longer mean duration (27 m.yrs.) than the intermediate class (21.5 m.yrs.) and the common class (15.5 m.yrs.). 66% of the 50 endemic New Zealand species have a fossil record (mean duration 14 m.yrs.), whereas only 40% of the 180 cosmopolitan species have a New Zealand fossil record (mean duration 25 m.yrs.).
Biogeography
Fifty percent of our species are cosmopolitan, 14% endemic and 10% have a South-west Pacific distribution. All 21 brackish-restricted species are cosmopolitan. There is one endemic genus (Zeaflorilus) and one third of the endemic species belong to three genera - Notorotalia (6 spp.), Pileolina (5 spp.) and Quinqueloculina (5 spp.). New Zealand appears to be the centre of greatest diversity for the former two genera. 38% of the endemic species occur commonly around New Zealand with many as characterising species of faunal associations - Spiroplectinella proxispira, Elphidium novozealandicum, Nonionellina flemingi, Notorotalia finlayi, Pileolina zealandica, Virgulopsis turris, Zeaflorilus parri. All the New Zealand brackish and mid shelf faunal associations occur overseas, but 13 of the 16 normal marine salinity, inner shelf associations appear to be restricted to New Zealand. Most endemic species are widespread around New Zealand with just 6 having distributions restricted to a single province - Glabratellina kermadecensis (Kermadecian), Discorbinella deflata (Moriorian), Fissurina baccata, Elphidium excavatum f. oirgi, Pileolina calcarata, P. harmeri (Aupourian).
A simplified version of the composite locality presence/absence data set on New Zealand’s normal marine, shallow water foraminifera was analysed by clustering Jaccard coefficients. Six mappable biogeographic provinces were identified from the resulting dendrogram - Kermadecian, Aupourian (north-east North Island), New Zealand (most of the three main islands), Fiordland, Moriorian (Chatham Islands) and Antipodean (Subantarctic Islands). These foraminiferal provinces are closely similar to the classic, molluscan-defined marine provinces, except that the classic Cookian and Forsterian Provinces are combined into the New Zealand Province and a separate Fiordland Province is recognised. Another minor difference is that the Far North and Waitemata Harbour are excluded from the foraminiferal Aupourian province and group with the New Zealand Province.
The number of shallow water benthic foraminiferal species present in the Fiordland and outlying island provinces is considerably fewer than in the two mainland provinces, because of less extensive study, reduced range of habitats, less likelihood of successful trans-oceanic dispersal (islands), young age of island group (Kermadecian), or cooler water (Fiordland, Antipodean). Diversity decreases from north to south in the well-studied mainland provinces, with 304 species in Aupourian and 270 in the New Zealand. Thirty warm, shallow-water species are restricted to the Aupourian Province, which is strongly influenced by the warm East Auckland Current, and a further 8 species are restricted to the Aupourian plus the Kermadecian. Few species are restricted to the other provinces - Kermadecian (6), New Zealand (9), Fiordland (0), Moriorian (1) and Antipodean (0). The pattern of brackish water foraminiferal biogeography in New Zealand differs from that of the normal marine species and appears to be more similar to that displayed by terrestrial plants and animals.
Dispersal
Our results show that there are two groups of shallow water foraminiferal species. One group has been able to rapidly disperse widely around the world, crossing oceanic barriers of up to 1500 km width (Tasman Sea), whereas the other group (including the New Zealand endemics) have not successfully dispersed to other countries. Transport on the feet or feathers of migratory wading seabird is postulated as the most likely dispersal mechanism for the cosmopolitan brackish foraminiferal fauna. Trans-oceanic current transport of suspended juveniles is the most favoured dispersal mechanism for the majority of the widespread normal marine, shallow water species, possibly assisted at times by “island-hopping” across the wider oceanic barriers. We infer from their modern New Zealand distribution patterns that three species (Elphidium vellai, Virgulinella fragilis, Siphogenerina raphana) have been introduced in ships’ ballast water within the last century or so. A fourth (Spiroloculina carinata) may also but is less certain.
Paleoenvironmental assessment
A multiplicity of physical and biological factors determine the modern ecologic distribution patterns of foraminifera. The correlation of some of these factors with the presence or abundance of certain foraminiferal taxa or associations has been documented in modern faunas and may be used to assess the paleoenvironment of fossil foraminiferal faunas. The validity of this uniformitarian approach is largely accepted for the Quaternary and Neogene but becomes less reliable going back in time through the Paleogene and Cretaceous.
Fossil foraminiferal faunas can provide assessments, at varying levels of accuracy, of a number of paleoenvironmental factors of value to geological, paleoclimatic and paleoceanographic studies. Planktic foraminiferal percentage, maximum size, encrustation, diversity, coiling ratios and taxonomic census data can be used to estimate oceanicity and paleotemperature and to give an indication of water depth. Benthic foraminiferal diversity and composition by suborder sometimes provide a general indication of the past environment, but the benthic taxonomic composition and recognition of faunal associations allow more detailed assessments of water depth, intertidal level, salinity, exposure to water turbulence, bottom oxygen concentrations, water temperature and carbon flux. Charts and tables summarising the correlation between modern foraminifera and a number of these factors are presented to assist in paleoenvironmental assessments.
Post-mortem faunal changes, such as test breakdown, dissolution, winnowing, bed-load transport and reworking, can modify the composition of foraminiferal faunas and affect paleoenvironmental assessments. These changes may be recognised by study of the preservational state and test size distribution and composition of the benthic foraminifera and be useful in refining the paleoenvironmental assessment.
A method for rapid paleoenvironmental assessment of individual fossil faunas is outlined, based largely on an estimate of the planktic percentage and identification of the dominant benthic taxa or faunal association.
Keywords. Foraminifera; shallow water; brackish environments; shelf environments; systematics; species frequency; species duration; dispersal mechanisms; biogeography; benthic foraminiferal associations; ecologic distribution; paleoenvironmental assessment; New Zealand; Cavalli Islands; Helena Bay; Waitemata Harbour; Great Barrier Island; Pauatahanui Inlet; Wanganui Bight; Queen Charlotte Sound; Oparara Inlet; Purakanui Inlet; Port Pegasus
... Multiple studies have focused on recent (e.g. Vella, 1957;Eade, 1967;Hayward et al., 1999;Kawagata, 2001;Hayward et al., 2010, and references therein;Martin et al., 2010;Hayward et al., 2013) and fossil benthic foraminifera in New Zealand (e.g. Boersma, 1984a;Hornibrook et al., 1989;Nees, 1994Nees, , 1997Kawagata, 1999;Nees et al., 1999;Hayward, 2002, and references therein;Hayward, 2004;Hayward et al., 2004;Mancin et al., 2013); however, fewer studies have dealt with material collected during ocean drilling expeditions in the Tasman Sea (Boersma, 1986;Kurihara and Ken-to Pliocene benthic foraminifera from seven DSDP sites from Leg 90 (586B, 587, 588, 589, 590, 591, and 594). ...
... Here we present a more detailed analysis of the paleodepth distribution of benthic foraminifera across the Late Miocene-Early Pliocene at this site. Our paleobathymetric estimates are based on the presence and abundance of depth-dependent species, with paleodepths and upper depth limits derived from Van Morkhoven et al. (1986) and Hayward et al. (1999Hayward et al. ( , 2001Hayward et al. ( , 2004Hayward et al. ( , 2010. The pattern of occurrence of benthic foraminifera at various depths is shown in Fig. 8. ...
... The study interval contains a high percentage of species that are common at lower bathyal to abyssal depths, such as Bulimina truncana (up to 11 %), Cibicidoides mundulus (up to 9 %), Epistominella exigua (up to 13 %), Globocassidulina subglobosa (up to 20 %), Oridorsalis umbonatus (up to 11 %), and Uvigerina peregrina (up to 16 %). Stilostomellids (maximum abundance 13 %) and Nodosariids (maximum abundance 9 %) have been observed in all the samples and are typically abundant at bathyal and abyssal depths (Hayward et al., 1999Kennett and Casey, 1969). Abyssal taxa (> 2000 m) such as Nuttallides umbonifera make up < 3 % of the assemblages. ...
Modern and fossil benthic foraminifera have been widely documented from New Zealand, but detailed studies of material collected from drilling expeditions in the Tasman Sea are scarcer. This study aims to provide an updated taxonomic study for the Late Miocene–Early Pliocene benthic foraminifera in the Tasman Sea, with a specific focus on the paleoceanographic phenomenon known as the Biogenic Bloom. To achieve these goals, we analysed 66 samples from Integrated Ocean Drilling Program (IODP) Site U1506 located in the Tasman Sea and identified a total of 98 taxa. Benthic foraminifera exhibit good preservation, allowing for accurate taxonomic identification. The resulting dataset serves as a reliable and precise framework for the identification and classification of the common deep-water benthic foraminifera in the region. The paleobathymetric analysis based on depth-dependent species indicates deposition at lower bathyal depths. Additionally, the quantitative analysis of the benthic foraminiferal assemblages allowed us to explore their response to the Biogenic Bloom at Site U1506. The paleoenvironmental analysis, focused on the Early Pliocene part of the Biogenic Bloom, points to high-productivity conditions driven by phytoplankton blooms and intensified vertical mixing of the ocean waters. These results provide valuable insights into the paleoceanographic events in the Tasman Sea, particularly the Biogenic Bloom, highlighting the significance of benthic foraminifera as reliable proxies for deciphering paleoenvironmental conditions. The taxonomic identifications and paleoenvironmental interpretations presented herein will aid in future paleoceanographic studies and facilitate comparisons with other deep-sea regions.
... A few specimens were retrieved from higher intervals within the Otahuhu and Tamaki Formation sequence, as noted in the species list. The main texts used for the identification of the molluscs are Marwick (1948), Laws (1950), Powell (1979), Beu and Maxwell (1990), Beu and Raine (2009) and MolluscaBase (2021); corals is Cairns (1995), barnacles is Buckeridge (1983), Foraminifera are Hayward et al. (1999a) and Hayward et al. (2021) and ostracods is Morley and Hayward (2012). ...
... The foraminiferal assemblages appear to be of mixed provenance. In modern seas Ammonia aoteana is common and often dominant (at >80% of faunal assemblages) in sheltered lower parts of estuaries and upper reaches of coastal inlets from mid-tidal to shallow subtidal (c.10 m) depths in mud to muddy gravelly sand (Hayward et al. 1999a;Hayward 2014). By contrast, in the Pleistocene sequence at Whanganui, Notorotalia and the extinct species Rotalia wanganuiensis are codominant in foraminiferal assemblages of coarse-grained shelly sediment inferred to have been deposited in turbulent paleoenvironments of normal marine salinity at innermost shelf (0-25 m) depths (Abbott 1997). ...
... The moderately common foraminiferal faunas from this interval are co-dominated by Cibicidoides dispars and Ammonia aoteana with subdominant Melonis, Rotalia wanganuiensis, Notorotalia and Elphidium spp. This assemblage could occur together in sheltered, normal salinity sand at 0-20 m depth (Hayward et al. 1999a). ...
... Species from four branches are still present around New Zealand today with one probable recent ship's ballast introduction (E. vellai) from Japan (Hayward et al., 1999). ...
... profunda) occurs in deeper water (outer shelf to mid-bathyal, 100-1000 m) whereas the other seven are shelf-restricted and most abundant at inner-mid shelf depths (0-100 m). Of this latter group, four species occur right around New Zealand from North Cape to the subantarctic Auckland and Campbell Islands (Hayward et al., 1999): one (N. olsoni) is restricted to the warm waters of northeastern North Island, one (N. ...
... inornata) occurs between the southern North Island and the subantarctic islands, and the other (N. zealandica) occurs around both main islands but does not extend into the subantarctic zone (Hayward et al., 1999;Fig. 12). ...
Most previous accounts summarising the biogeography and species durations of smaller calcareous benthic foraminifera have been based on literature reviews or on a massive North American database that had been taxonomically standardised. In this review we limit consideration to extant and fossil families or genera (from nearshore, open shelf, and deep-sea environments) with modern reviews that have standardised their global morphotaxonomy and where available, are complimented by molecular studies.
We confirm previous studies that indicate most shelf species have limited geographic ranges and the majority of deep-water species are widespread and cosmopolitan or nearly so. In our intertidal and inner shelf groups only one species (molecular and morphological), Ammonia veneta, has a cosmopolitan distribution, although four warm-water morphospecies, of Ammonia and Rugobolivinella, have or had distributions that spanned more than one ocean in equatorial latitudes. The majority of both warm- and cool-water species in these groups are regionally or locally-restricted endemics (92% of Bolivinellidae, 100% of Tubulogenerina, 73% of Ammoniidae). The biogeographic distribution of the two rarer, warm-water groups (Bolivinellidae, Tubulogenerina) changed dramatically through the Cenozoic with the Paleocene–Eocene North American–European distribution of Bolivinellidae switching to purely Indo-Pacific by the Pliocene–Quaternary.
In our shelf–upper bathyal groups (Notorotaliiidae, Plectofrondiculariidae), two genera have been restricted to the Southern Hemisphere since their Eocene originations with their greatest diversity throughout in New Zealand and Australia, respectively. The dominantly cold-water notorotaliid genus Buccella has a biogeographic distribution largely restricted to the Arctic Ocean and both coasts of North and South America. Most notorotaliid species are locally or regionally endemic (100% of Notorotalia, Parrellina, Porosorotalia, 75% of Buccella). At least 50–60% of species in five extinct mid-bathyal–abyssal families are cosmopolitan and have been throughout the Cenozoic since their originations. The majority of these deep-sea species with more-restricted distributions are rare, and many could possibly be more widespread with further extensive study.
This review found that the shortest mean species durations (4–5 myrs) occur in two groups of rather rare, tropical–subtropical inner-shelf foraminifera with many locally endemic species. In cooler and progressively deeper water environments the mean species durations increase to 7–11 myrs for temperate shelf–bathyal taxa (Notorotaliidae), 20 myrs for an extinct mid-shelf to bathyal family (Plectofrondiculariidae) and 41–50 myrs for five extinct mid-bathyal–abyssal families (Chrysalogoniidae, Ellipsoidinidae, Glandulonodosariidae, Pleurostomellidae, Stilostomellidae). One species in each of four of these deep-water families had a species duration of 150–120 myrs.
... Benthic generic (and Bulimina species) groups used as indicators of provenance from various depth ranges, based on modern studies from around New Zealand (Hayward et al., 1999(Hayward et al., , 2010(Hayward et al., , 2013. ...
... ( Table 2) based on its recorded modern distribution around New Zealand (Hayward et al., 1999(Hayward et al., , 2010(Hayward et al., , 2013. The percentage of tests from each group in each sample was used to help interpret the data (e.g., Hayward et al., 2019). ...
The 2016 Mw 7.8 Kaik¯oura Earthquake triggered simultaneous turbidity currents down ten submarine canyons along a 200 km stretch of the continental slope, east of New Zealand. They discharged into the abyssal Hikurangi Channel which flows >1500 km northwards along the trench floor as part of the Hikurangi Subduction Margin.
One hundred and thirty-six foraminiferal samples from the 2016 turbidites and pre-turbidite sediment from 25 canyon/channel cores, collected during surveys 3 days, 2.5 and 8 months after the event, were used to provide insights into the complexities of these submarine gravity flows. Transport in the turbidity currents produced no significant additional breakage of foraminiferal tests, even when transported 650 km down channel. We conclude that highly variable planktic foraminiferal fragmentation index (FI) values indicate that test breakage in turbidite samples is primarily inherited from dissolution on the seafloor at their source area, which is often anomalously high because of lowered sediment pH as a result of the breakdown of the high organic carbon flux. All turbidite and pre-turbidite faunas have strong signatures of downslope displacement (presence of shallow-water benthics, size-sorted test distributions, low percentage of planktics). This is not surprising as all cores were taken in the canyon or channel floor pathways to collect
turbidite sequences, with turbidity flows estimated to have a recurrence time of ~150 yrs. Pre-turbidite faunas can be distinguished from the 2016 turbidites’ faunas by having greater percentage of planktics and lower ratios of shallow to deep benthic tests (S/D Index). 210Pb profiles show that the laminated pre-turbidite sediment accumulated slowly and the foraminiferal content indicates it is composed of reworked earlier turbidite sediment with the addition of contemporaneous deep-water benthic tests and the rain of planktic tests mixed in.
There are no consistent trends in any foraminiferal faunal parameters with distance displaced in the turbidity current (10–650 km). Rather, intra-turbidite (10–75 cm thick) faunal variability in a single core is often considerable and is attributed to erosion and entrainment of deep-seafloor tests by the passage of turbulent turbidity current heads, variable source canyon depths, different source canyon provenances, and test-size
sorting during transport and deposition resulting in vertical and longitudinal fractionation of the smallest tests and finest sediment.
This study suggests that a single foraminiferal fauna is often, but not always, insufficient to characterise a turbidite or for use in correlation with turbidites in other cores or exposures.
... Ecology notes: This species is commonly found in shallow environments rich in organic matter (Dubois et al., 2021) but also in rocky environments, algal substrates and coral reefs (Hayward et al., 1999;Murray, 2006 Description: The vitreous shell is slightly trochoid, with a circular peripheral contour, more or less lobed. The margin is rounded or slightly acute. ...
There is a gap in knowledge about the biodiversity of living foraminifera (protozoa) in Brazil, particularly in coastal environments. In Sepetiba Bay (SE Brazil), a coastal system highly impacted by anthropogenic activities, several previous studies have been carried out on foraminifera based on total (living + dead) assemblages and sub-fossil records. Thus, this study intends to analyze for the first time the species richness of living foraminifera (stained with Rose Bengal) in Sepetiba Bay. Based on the morphological characteristics, 214 living species were identified in 50 samples collected in Sepetiba Bay in May 2022. The number of living specimens was counted as 6548. Living foraminifera density was < 252 specimens per gram of sediment and the species richness (S) ranged from 15 to 61 (mean 16.9 ± 15.5) in the analyzed stations. The main taxonomic classes found were Globothalamea and Tubothalamea. The main Globothalamea taxa belonged to the genus Ammonia, with Ammonia tepida, Ammonia buzasi, and Ammonia rolshauseni standing out, as well as the Bolivina, Buliminella, and Elphidium, represented mainly by Bolivina striatula, Buliminella elegantissima, and Elphidium excavatum. A non-Metric Multidimensional Scaling (nMDS) and cluster analysis based on a presence-absence matrix and Bray–Curtis similarity index allowed the identification of two main groups of stations: 1. Located in the innermost areas of Sepetiba Bay and surrounding the mainland and Marambaia Barrier Island, at shallower depths, with lower diversity; 2. an outermost group of stations with higher diversity in areas with greater oceanic influence. Compared with previous studies, the results of this work suggest an enlargement of the “innermost” zone with less diversity towards the oceanic region of Sepetiba Bay. This work shows that even using a matrix of presence/absence of living foraminifera and species richness, it is possible to distinguish environments in coastal systems. Data based on the living foraminifera is needed to understand current biodiversity to better characterize coastal environments and carry out biomonitoring studies.
... These species are reported for the first time in the Brunei shelf starting at MES 27 (92 mwd) until MES 29 (190 mwd), which is shallower than the usual distribution in the region, but since the samples are sieved through 500 micrometres, there is a possibility of loss of lagenid species. Lagenids are infaunal and usually occur in deeper marine environments below the photic zone (50 m) [28,63], feeding on the available organic matter within the sediment [18]. They are also found in sites with higher clay content, which is seen in one of the nearby wreck sites, (Dolphin wreck) DW [18], but does not have a higher species richness compared to lageninds found in much deeper depth within the MES sites below 60 mwd. ...
The marine benthic diversity of the Palawan/North Borneo ecoregion is poorly known, despite its implied unique high species richness within the Coral Triangle. The present study investigated the diversity and distribution of benthic foraminifera on the Brunei shelf. The objectives were to determine the species composition of sediment samples collected from 11 sites, extending 70 km from the Brunei coastline and along a depth gradient of 10-200 m. We retrieved a total of 99 species, belonging to 31 families and 56 genera, out of which 52 species represented new records for Brunei and probably the ecoregion. Using presence/absence data, analyses were also performed to compare species diversity patterns (species richness, occupancy, taxonomic distinctness) and species assemblage similarity across the sites. For further insight into the relationship between distribution and depth-associated environmental conditions, we undertook stable isotope analyses of selected species of Rotaliida, Miliolida, and Lagenida. Oxygen isotope values were positively correlated with depth and species distribution, confirming cooler temperatures at greater depth. The carbon isotope data revealed species differences relating to habitat and food source specificity and a biomineralization effect. Close to one-third of the species were recorded from single sites, and species richness and taxonomic distinctness increased with depth and were greatest at the second deepest site (144 m). Together, these findings suggest data underrepresentation of diversity, habitat disturbance in shallower water, and species specialization (adaptation) in deeper water. Importantly, assemblage similarity suggests the occurrence of at least three marine biotopes on the Brunei shelf (10-40 m, 40-150 m, and >150 m). This study contributes significantly to our understanding of the local and regional patterns of foraminiferal diversity and distribution.
... On the other hand, Ammobaculites agglutinatus ( Fig. 11(V)) and Ammobaculites sp. (Fig. 11(L)) show a preference for shallower depths. Ammobaculites assemblages are most common in recent slightly brackish, sheltered, shallowsubtidal to the mid-tidal harbor and estuarine organic-rich mud facies (Murray, 1991;Hayward et al., 1999;Haig, 2020). Together with the mentioned species in Unit M1, the occurrence of shallow-water benthic foraminifera, and deep and shallow marine ostracods were recorded. ...
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We report on the distribution of contemporary foraminifera in salt marshes in Mission Bay and Carpinteria Slough, Southern California. Combining these data with existing datasets from Seal Beach and Tijuana, we explore the potential for a regional training set to underpin quantitative reconstructions of paleoenvironmental change from foraminifera preserved in salt-marsh sediments. We demonstrate that species’ distributions are highly dependent on elevation, suggesting fossil foraminiferal assemblages here, as in many other regions, are useful depositional elevation indicators. Transfer functions provide predictions from Mission Bay cores with decimeter-scale uncertainties. Nevertheless, interpretation of marsh-surface elevation change is complicated by a complex geomorphic setting and anthropogenic impacts. An abrupt change in elevation in the mid-1700s may be related to lateral spreading of water-saturated sediments during an earthquake on the Rose Canyon fault, suggesting the potential for foraminifera to support new palaeoseismic and sea-level records for the region.
Benthic Foraminifera are important elements of coral reef ecosystems and valuable proxies for monitoring reef health in the face of local, regional and global stressors. Here Foraminifera preserved in a sediment core from the One Tree Reef (OTR) lagoon on the southern Great Barrier Reef (GBR) are used to quantify ecological changes associated with European colonisation (late 1700’s) and the subsequent industrialisation of Australia (1950’s onward). Core samples are compared to published benthic grab samples from three reefs to compare spatial and temporal variation. Standard measures of richness, diversity and foraminiferal assemblage composition indicate significant differences between the Recent assemblages of OTR lagoon and those from Heron and Wistari reef lagoons. However, there is no discernible change in the OTR lagoon core assemblages from the last four centuries in any of the richness or diversity indices examined. While benthic grabs likely undersample infaunal foraminifera relative to core samples, these foraminiferal assemblages indicate the OTR lagoon contains a living example of a pre-colonial GBR lagoon ecosystem. Without cores from Heron and Wistari it is unknown if their foraminiferal assemblages have changed due to recent anthropogenic activity or if they have always been distinct.
Supplementary material at https://doi.org/10.6084/m9.figshare.c.6223250
Several very large, taxonomically standardized data sets have been compiled and utilized to investigate biogeographic and evolutionary patterns of continental margin benthic foraminifera. Mean partial species durations for 87 frequently occurring and 180 rarely occurring species on the Atlantic continental margin of North America are the same, namely 21 m.y. The global fossil record of these species indicates no center or centers of origin and indicates very rapid dispersal. The Miocene had the greatest number of first occurrences with 46%, followed by the Pleistocene, Pliocene and Oligocene with approximately 13% each. The remaining 14% first occur in the Eocene, Paleocene, and Cretaceous. Species with a wide geographic distribution often exhibit longer species durations than those with narrow geographic ranges. The vast majority of endemic species (150 of 175) occur rarely and have no fossil record. 1989 The Paleontological Society.
The original material of Brizalina aenariensis Costa, 1856, type-species of the genus, has allowed for its revision, redescription and emended diagnosis. The characters of the species demonstrate that: a) the genus Brizalina has to be considered a junior synonym of Bolivina d'Orbigny, 1839; b) Bolivina subaenariensis Cushman, 1937 has to be considered a junior synonym, of Bolivina aenariensis (Costa). On the basis of its paleogeographical distribution in the Recent sediments of the Mediterranean, and its particular abundance during the cold intervals of Pleistocene, the species can be considered a valid paleoclimatic marker. -Author