Meiobenthos in the Sub-equatorial Pacific Abyss

Radziejewska, Teresa

doi:10.1007/978-3-642-41458-9

Cited by 15 publications

(28 citation statements)

References 14 publications

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“…in seafloor photographs taken at a site to the south of the central CCZ (4 • N, 136 • W; 4469 m depth). Smith et al (1996) recovered phytodetritus in multicore samples collected along the 140 • W line from 5 • N to 5 • S. Further east, and within the CCZ, Radziejewska (2002) observed a 'very thin layer of a fluffy material, greenish-brown in color' (i.e., phytodetritus) on the surfaces of some cores collected in 1997 in part of the IOM contract area (centered at 11 • 04 N, 119 • 40 W; 4380-4430 m depth) that had been subject 2 years earlier to an experimental disturbance designed to simulate the effects of nodule mining (see also Radziejewska, 2014). Samples of this material, which was very patchily distributed, contained chloropigments and intact diatoms.…”

Section: Responses To Food Inputsmentioning

confidence: 99%

The Contribution of Fine Sieve Fractions (63–150 μm) to Foraminiferal Abundance and Diversity in an Area of the Eastern Pacific Ocean Licensed for Polymetallic Nodule Exploration

Gooday

Goineau

2019

Front. Mar. Sci.

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The sieve mesh sizes used in benthic foraminiferal studies exert a strong influence on faunal densities and composition. We examined the consequences of including finer (63-150 µm) size classes in a study of Rose Bengal stained ('live') and dead foraminifera in 5 Megacorer samples (0-1 cm layer) from abyssal sites in the eastern Clarion-Clipperton Zone (CCZ; equatorial Pacific), a region with commercially significant deposits of polymetallic nodules. More than 60% of intact specimens originated from the finer (<150 µm) fractions, with over half being picked from 63 to 125 µm residues. Test fragments, mainly agglutinated tubes, were also abundant but were more evenly distributed between coarser and finer residues. The two fractions yielded the same main groups (a mixture of formal taxa and informal groupings) and were dominated by single-chambered forms ('monothalamids'), the majority undescribed. Some were disproportionately abundant in finer fractions: rotaliids in the stained ('live'), textulariids in the dead, and trochamminids, Lagenammina spp., Nodellum-like forms, saccamminids and spheres in both assemblages. However, the most striking difference was the much greater abundance of tiny, largely undescribed spherical agglutinated morphotypes in the <150-µm fractions. Our 5 samples yielded 462 morphospecies, of which 313 occurred in <150-µm fraction and 170 were confined to this fraction. Twelve of the 31 top-ranked species in the stained assemblage were more or less limited (>90%) to the finer fractions; the corresponding number for the stained + dead assemblage was 12 out of 35. Of the 46 most abundant species in the stained + dead assemblage, 35 were monothalamids (mainly spheres, Lagenammina spp., Nodellum-like forms, and saccamminids), the remainder being rotaliids (3), hormosinids (3), trochamminids (3) and textulariids (2). By far the most abundant species overall, a tiny agglutinated sphere, was almost entirely confined to the finer fractions. Although small foraminifera that pass through a 150-µm screen are time-consuming to analyze, they constitute an important

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Section: Responses To Food Inputsmentioning

confidence: 99%

The Contribution of Fine Sieve Fractions (63–150 μm) to Foraminiferal Abundance and Diversity in an Area of the Eastern Pacific Ocean Licensed for Polymetallic Nodule Exploration

Gooday

Goineau

2019

Front. Mar. Sci.

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“…For effective mining, the seabed collector vehicle will likely follow a ‘lawnmower pattern’, moving back and forth along roughly parallel tracks, leaving only small remnant unmined area with high-value nodule patches [ 14 ]. However, nodule fields themselves are patchily distributed on 0.1–10 km scales [ 20 ], often following the ridge and valley topography characteristic of the CCZ [ 21 ], suggesting that areas of minable nodules will be separated by swathes of low-value sediments of order 0.1 to 10 km wide. This suggests that within a typical mining area, covering between 10 and >100 km 2 , nodule-rich patches would be nearly totally disturbed, while intervening unmined swathes potentially much greater in area would be impacted by sediment plumes.…”

Section: Introductionmentioning

confidence: 99%

“…In all, 14 tows, each around 2.5 km long, were carried out on a site of 200×2500 m and the impact was observed from deep-sea camera tows and sediment samples [ 51 ]. The test site was revisited in April-May 1997, June 2000 [ 21 , 52 ] and in March 2015 as part of the JPIO project “Ecological Aspects of Deep-Sea Mining” [ 53 ].…”

Section: Introductionmentioning

confidence: 99%

Biological responses to disturbance from simulated deep-sea polymetallic nodule mining

et al. 2017

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Commercial-scale mining for polymetallic nodules could have a major impact on the deep-sea environment, but the effects of these mining activities on deep-sea ecosystems are very poorly known. The first commercial test mining for polymetallic nodules was carried out in 1970. Since then a number of small-scale commercial test mining or scientific disturbance studies have been carried out. Here we evaluate changes in faunal densities and diversity of benthic communities measured in response to these 11 simulated or test nodule mining disturbances using meta-analysis techniques. We find that impacts are often severe immediately after mining, with major negative changes in density and diversity of most groups occurring. However, in some cases, the mobile fauna and small-sized fauna experienced less negative impacts over the longer term. At seven sites in the Pacific, multiple surveys assessed recovery in fauna over periods of up to 26 years. Almost all studies show some recovery in faunal density and diversity for meiofauna and mobile megafauna, often within one year. However, very few faunal groups return to baseline or control conditions after two decades. The effects of polymetallic nodule mining are likely to be long term. Our analyses show considerable negative biological effects of seafloor nodule mining, even at the small scale of test mining experiments, although there is variation in sensitivity amongst organisms of different sizes and functional groups, which have important implications for ecosystem responses. Unfortunately, many past studies have limitations that reduce their effectiveness in determining responses. We provide recommendations to improve future mining impact test studies. Further research to assess the effects of test-mining activities will inform ways to improve mining practices and guide effective environmental management of mining activities.

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“…2009; Miljutina et al, 2010;Miljutin et al, 2015), DORD 3 (Kaneko et al, 1997;Shirayama and Fukushima, 1997) and CIIC 4 (Trueblood and Ozturgut, 1997; study conducted by the National Oceanographic and Atmospheric Administration's Ocean Minerals and Energy Division; see also the meta-analytical papers by Vanreusel et al, 2010;Radziejewska, 2014;Singh et al, 2016 and the paper by Jones et al, 2017). Temporal variability in CCFZ meiofauna was so far only assessed by comparing different years (Trueblood and Ozturgut, 1997;Shirayama, 1999;Radziejewska et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Limited Spatial and Temporal Variability in Meiofauna and Nematode Communities at Distant but Environmentally Similar Sites in an Area of Interest for Deep-Sea Mining

et al. 2017

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To be able to adequately assess potential environmental impacts of deep-sea polymetallic nodule mining, the establishment of a proper environmental baseline, incorporating both spatial and temporal variability, is essential. The aim of the present study was to evaluate both spatial and intra-annual variability in meiofauna (higher taxa) and nematode communities (families and genera, and Halalaimus species) within the license area of Global Sea mineral Resources (GSR) in the northeastern Clarion Clipperton Fracture Zone (CCFZ), and to determine the efficiency of the current sampling of meiofauna and nematode diversity. In October 2015, three polymetallic nodule-bearing sites, about 60–270 km apart, located at similar depths (ca. 4,500 m) were sampled, of which one site was sampled in April in that same year. Despite the relatively large geographical distances and the statistically significant, but small, differences in sedimentary characteristics between sites, meiofauna and nematode communities were largely similar in terms of abundance, composition and diversity. Between-site differences in community composition were mainly driven by a set of rare and less abundant taxa. Moreover, although surface primary productivity in April exceeded that in October, no significant changes were observed in sedimentary characteristics or in meiofauna and nematode communities. At all sites and in both periods, Nematoda were the prevailing meiofaunal phylum, which was in turn dominated by Monhysterid genera and Acantholaimus. Our findings support the earlier purported notion of a low degree of endemism for nematode genera and meiofauna taxa in the deep sea, and hint at the possibility of large distribution ranges for at least some Halalaimus species. Taxon richness estimators revealed that the current sampling design was able to characterize the majority of the meiofauna and nematode taxa present. To conclude, implications of the present findings for environmental management and future research needs are provided

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Meiobenthos in the Sub-equatorial Pacific Abyss

Cited by 15 publications

References 14 publications

The Contribution of Fine Sieve Fractions (63–150 μm) to Foraminiferal Abundance and Diversity in an Area of the Eastern Pacific Ocean Licensed for Polymetallic Nodule Exploration

The Contribution of Fine Sieve Fractions (63–150 μm) to Foraminiferal Abundance and Diversity in an Area of the Eastern Pacific Ocean Licensed for Polymetallic Nodule Exploration

Biological responses to disturbance from simulated deep-sea polymetallic nodule mining

Limited Spatial and Temporal Variability in Meiofauna and Nematode Communities at Distant but Environmentally Similar Sites in an Area of Interest for Deep-Sea Mining

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