Rapid deterioration of sediment surface habitats in Bellingham Bay, Washington State, as indicated by benthic foraminifera

Abstract. In this study we present an initial dataset of Mn/Ca and Fe/Ca ratios in tests of benthic foraminifera from the Peruvian oxygen minimum zone (OMZ) determined with SIMS. These results are a contribution to a better understanding of the proxy potential of these elemental ratios for ambient redox conditions. Foraminiferal tests are often contaminated by diagenetic coatings, like Mn rich carbonate- or Fe and Mn rich (oxyhydr)oxide coatings. Thus, it is substantial to assure that the cleaning protocols are efficient or that spots chosen for microanalyses are free of contaminants. Prior to the determination of the element/Ca ratios, the distributions of several elements (Ca, Mn, Fe, Mg, Ba, Al, Si, P and S) in tests of the shallow infaunal species Uvigerina peregrina and Bolivina spissa were mapped with an electron microprobe (EMP). To visualize the effects of cleaning protocols uncleaned and cleaned specimens were compared. The cleaning protocol included an oxidative cleaning step. An Fe rich phase was found on the inner test surface of uncleaned U. peregrina specimens. This phase was also enriched in Al, Si, P and S. A similar Fe rich phase was found at the inner test surface of B. spissa. Specimens of both species treated with oxidative cleaning show the absence of this phase. Neither in B. spissa nor in U. peregrina were any hints found for diagenetic (oxyhydr)oxide or carbonate coatings. Mn/Ca and Fe/Ca ratios of single specimens of B. spissa from different locations have been determined by secondary ion mass spectrometry (SIMS). Bulk analyses using solution ICP-MS of several samples were compared to the SIMS data. The difference between SIMS analyses and ICP-MS bulk analyses from the same sampling sites was 14.0–134.8 μmol mol−1 for the Fe/Ca and 1.68(±0.41) μmol mol−1 for the Mn/Ca ratios. This is in the same order of magnitude as the variability inside single specimens determined with SIMS at these sampling sites (1σ[Mn/Ca] = 0.35–2.07 μmol mol−1; 1σ[Fe/Ca] = 93.9–188.4 μmol mol−1). The Mn/Ca ratios in the calcite were generally relatively low (2.21–9.93 μmol mol−1) but in the same magnitude and proportional to the surrounding pore waters (1.37–6.67 μmol mol−1). However, the Fe/Ca ratios in B. spissa show a negative correlation to the concentrations in the surrounding pore waters. Lowest foraminiferal Fe/Ca ratios (87.0–101.0 μmol mol−1) were found at 465 m water depth, a location with a strong sharp Fe peak in the pore water next to the sediment surface and respectively, high Fe concentrations in the surrounding pore waters. Previous studies found no living specimens of B. spissa at this location. All these facts hint that the analysed specimens already were dead before the Fe flux started and the sampling site just recently turned anoxic due to fluctuations of the lower boundary of the OMZ near the sampling site (465 m water depth). Summarized Mn/Ca and Fe/Ca ratios are potential proxies for redox conditions, if cleaning protocols are carefully applied. The data presented here may be rated as base for the still pending detailed calibration.

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Impact of the 2011 off the Pacific coast of Tohoku earthquake on a deep-sea benthic ecosystem: evidence from living and dead benthic foraminifera on the landward slope of the Japan Trench

10.5194/bg-2018-237 ◽

2018 ◽

Author(s):

Akira Tsujimoto ◽

Ritsuo Nomura ◽

Hidetaka Nomaki ◽

Kazuno Arai ◽

Mutsuo Inoue ◽

...

Keyword(s):

Benthic Foraminifera ◽

Deep Sea ◽

Pacific Coast ◽

Tohoku Earthquake ◽

Radioactive Material ◽

Japan Trench ◽

Sediment Surface ◽

Foraminiferal Assemblage ◽

The Pacific ◽

The Impact

Abstract. We examined the impact of the earthquake and tsunami following the 2011 off the Pacific coast of Tohoku earthquake on the deep-sea benthic ecosystems based on radionuclide and benthic foraminiferal analysis of core sediments, collected from 3200 and 3600 m water depths 5 and 17 months after the earthquake. Radionuclide analysis of the excess 210Pb, 134Cs, and 137Cs indicated that some of the analyzed sediment core recorded deposits before the earthquake, event deposits just after the earthquake, and deposits after the Fukushima Daiichi Nuclear Power Plant accident, which caused the release of a large amount of radioactive material 4 days after the earthquake. Uvigerina senticosa, Chilostomella oolina, and Elphidium batialis were the dominant species in the study area prior to the earthquake. In core 4W-2012, the original or pre-earthquake assemblage layer was covered by 5-cm-thick event deposits following the earthquake that contained a high diversity allochthonous foraminiferal assemblage. Following the episodic deposition, foraminiferal density drastically decreased and many species disappeared, resulting in a decrease in species diversity. Above 10 cm depth in the sediment, living specimens of opportunistic and competitive species gradually increased toward the sediment surface and became dominant in the top 1 cm of the core. Thus, the episodic deposition resulting from the earthquake caused a drastic decrease in the original benthic foraminifera and colonization of opportunistic species with a low diversity within 17 months. Although there were differences in vertical change in the radionuclides and benthic foraminifera between sites, faunal change may have already occurred 5 months after the earthquake.

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CANARIES IN THE COAL MINE: BENTHIC FORAMINIFERA IN THE ASSESSMENT OF PUGET SOUND, WASHINGTON STATE, BENTHIC ENVIRONMENTS

10.1130/abs/2017am-303443 ◽

2017 ◽

Author(s):

Ruth A. Martin ◽

◽

Elizabeth A. Nesbitt

Keyword(s):

Coal Mine ◽

Benthic Foraminifera ◽

Puget Sound ◽

Washington State

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FORAMINIFERA BENTIK PADA TERUMBU KARANG PULAU BUNAKEN

JURNAL PESISIR DAN LAUT TROPIS ◽

10.35800/jplt.8.1.2020.27464 ◽

2020 ◽

Vol 8 (1) ◽

pp. 56

Author(s):

Renaldi Kalalo ◽

Jane Mamuaya ◽

Hermanto W.K Manengkey ◽

Janny D Kusen ◽

Rignolda Djamaludin ◽

...

Keyword(s):

Coral Reef ◽

Benthic Foraminifera ◽

Good Condition ◽

Sediment Surface ◽

Coral Reef Ecosystem ◽

Reef Environment ◽

North Sulawesi ◽

Surface Samples ◽

Coral Reef Environment ◽

Reef Ecosystem

Study of benthic foraminifera on the coral reefs of Bunaken Island, North Sulawesi Province, was carried out with the aim of providing information regarding the description, distribution and FoRAM Index values on the coral reef environment of Bunaken Island. Sediment sampling in the field was carried out at 5 stations around the island, each area has been plotted on the map, with 3 repetitions and using a SCUBA tool at a depth of 3-8 meters. From observations of sediment surface samples at 15 points in 5 stations spread over Bunaken Island, 5,770 benthic foraminifera specimens have been identified. 81 species from 26 genera of foraminifera were identified and they were then grouped into functional groups to obtain the FoRAM Index. The Index were ranged from 7.18 to 10.5. This indicates that the environment of the coral reef waters around the island is still in good condition. Keywords : Benthic Foraminifera, Coral Reef Ecosystem, Bunaken Island. ABSTRAK Studi foraminifera bentik pada terumbu karang Pulau Bunaken Provinsi Sulawesi Utara dilakukan dengan tujuan untuk menyediakan informasi menyangkut deskripsi, peta sebaran dan nilai FoRAM Index pada lingkungan terumbu karang Pulau Bunaken. Kegiatan pengambilan sampel sedimen di lapangan dilakukan pada 5 stasiun di perairan Pulau Bunaken yang masing-masing areanya telah diplot dalam peta, dengan 3 kali pengulangan dan menggunakan alat SCUBA pada kedalaman 3-8 meter. Dari hasil pengamatan terhadap sampel sedimen permukaan dasar perairan pada 15 titik dalam 5 stasiun tersebar di Pulau Bunaken telah teridentifikasi sebanyak 5.770 spesimen foraminifera bentik. Hasil identifikasi foraminifera tersebut diperoleh 81 spesies foraminifera bentik yang termasuk dalam 26 genus. Spesies-spesies ini kemudian dikelompokkan ke dalam kelompok fungsional untuk mendapatkan FoRAM Index, dan diperoleh kisaran 7,18-10,5. Nilai ini mengindikasikan bahwa lingkungan perairan terumbu karang di sekitar pulau tersebut ada dalam keadaan masih baik dan sehat. Kata Kunci : Foraminifera Bentik, Ekosistem Terumbu Karang, Pulau Bunaken.

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Assessing behavioural traits of benthic foraminifera: implications for sediment mixing

Marine Ecology Progress Series ◽

10.3354/meps13334 ◽

2020 ◽

Vol 643 ◽

pp. 21-31

Author(s):

N Deldicq ◽

L Seuront ◽

D Langlet ◽

VMP Bouchet

Keyword(s):

Benthic Foraminifera ◽

Activity Index ◽

Ecosystem Processes ◽

Active Species ◽

Sediment Surface ◽

Vertical Position ◽

Foraminiferal Species ◽

Sediment Mixing ◽

Movement Ability ◽

Benthic Pelagic Coupling

The assessment of behavioural traits of marine organisms is increasingly recognized as a key issue to understanding their role in ecosystem processes such as bioturbation and nutrient cycling. The movement ability of intertidal foraminifera suggest that they may have a role, yet to be quantified, in benthic-pelagic coupling through their movement on the sediment surface, at the sediment-water interface and within the sediment. In this context, we investigated the behavioural traits of 5 benthic foraminiferal species typical of European temperate mudflats under standardized trophic light and temperature conditions. Behavioural traits related to motion of Ammonia tepida, Haynesina germanica, Cribroelphidium williamsoni, Miliammina fusca and Quinqueloculina seminula were assessed through their travelled distance, velocity, tortuosity of the path, position in the sediment and activity index. By analogy with macrofauna bioturbation functional groups, we describe the studied foraminifera as biodiffusor species with 3 sub-groups defined according to their vertical position in the sediment. C. williamsoni belongs to the epifaunal-biodiffusors, A. tepida and H. germanica belong to the surficial-biodiffusors, and Q. seminula and M. fusca are considered gallery-biodiffusors. Our results further suggest that features such as velocity, activity and tortuosity may mediate sediment-mixing intensity. Therefore, Q. seminula, H. germanica and C. williamsoni, which are the most active species, would have a larger effect on particle reworking rates than the less active A. tepida and M. fusca. Our results suggest that benthic foraminifera may play an underestimated role in bioturbation processes.

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Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

Journal of Paleontology ◽

10.1017/s0022336000058819 ◽

1988 ◽

Vol 62 (01) ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Ronald E. Martin

Keyword(s):

Deep Water ◽

Benthic Foraminifera ◽

Carbonate Platform ◽

Sedimentary Facies ◽

Depositional Environments ◽

Near Surface ◽

Sediment Gravity Flows ◽

Gravity Flows ◽

Platform Margin ◽

Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

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