We present the first global-scale analy- sis of standing stock (abundance and biomass) for 4 major size classes of deep-sea biota: bacteria, meta- zoan meiofauna, macrofauna and megafauna. The community standing stock decreases with depth; this is a universal phenomenon that involves a com- plex transition in the relative importance of the different size groups. Bacterial abundance and biomass show no decline with depth. All 3 animal size groups experience significant exponential de- creases in both abundance and biomass. The abun- dance of larger animals is significantly lower and decreases more rapidly than for smaller groups. The resulting drop in average body size with depth con- firms Thiel's size-structure hypothesis on very large spatial scales. In terms of their proportion of total community biomass, smaller size classes replace larger size classes. The upper continental slope is dominated by macrofaunal biomass, and the abyss by bacterial and meiofaunal biomass. The dramatic decrease in total community standing stock and the ascendancy of smaller organisms with depth has important implications for deep-sea biodiversity. The bathyal zone (200 to 4000 m) affords more eco- logical and evolutionary opportunity in the form of energy availability for larger organisms, and conse- quently supports higher macrofaunal and mega- faunal species diversity than the abyss (> 4000 m).

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Global bathymetric patterns of standing stock and body size in the deep-sea benthos

This article summarizes the most important and current methods for the determination of total organic carbon (TOC) in solid samples. The methods presented are chemical oxidation, combustion, acid treatment and ashing. We discuss the advantages of the different methods as well as problems that can be encountered during analysis. We give additional information on the detection techniques used for TOC determination and on the topic of volatile organic carbon (VOC) that deserves particular attention when carrying out TOC determinations, in particular with solid samples. We have compiled a concise survey of the literature covering 60 reports and tabulated the relevant analytical parameters.

Determination of total organic carbon: an overview of current methods

Data from 105 benthic trawls made in an area south of New England, USA between 40 and 5000 m show the fauna to be zoned with depth, areas of rapid faunal change separating regions of relative faunal homogeneity. Distinct faunal assemblages with characteristic catch rates, diversity, and dominant species are found on the shelf (40 to 264 m), upper continental slope (283 to 650 m), middle continental slope (653 to 1290 m), lower continental slope (1380 to 1947 m), the transitional region from slope to rise (2116 to 2481 m), the upper continental (2504 to 3113 m), the middle continental rise (3244 to 3470 m), and lower continental rise to abyssal plain (3879 to 4986 m). Catch rates and diversity are greatest on the lower continental slope and transition to the upper rise, and are lowest at the greatest depths. Dominance, particularly by echinoderms, is an important aspect of community structure. The 3 major taxa represented (decapod crustaccean, echinoderms, and fishes) do not always display the same patterns within and between assemblages. Generalities derived from study of a single group need not apply to all segments of the deep-ocean community. Overall patterns in the megafauna are similar to those described in other groups and areas, but species assemblages are not the same everywhere and perhaps too much has been made of the horizontal extent of zones. Trophic level is related to degree of zonation, but where predators are generalists their ranges may be wide rather than restricted. Diversity patterns can be understood in terms of the interrelationships of predation, competition, environmental heterogeneity, and trophic level. Faunal zones are of importance as the geographical units within which evolution, community development, and diversification take place.

The megabenthic fauna in the deep sea south of New England, USA

Treatise on Marine Ecology and Paleoecology, Paleoecology, Vol. 2. Geological Society of America, Washington (1957)

Determination of organic carbon in marine sediments: a comparison of two CHN-analyzer methods

The yield of organic C or total organic matter from a standard carbonate-free marine sediment containing 23.04% N-acetyl glucosamine (10% organic C) was determined using 1) a CHN analyzer on untreated sediment, 2) CHN analysis of acidified and filtered sediment, 3) CHN analysis of acidified centrifuged sediment, 4) wet oxidation by the Walkley and Black method, and 5) loss on ignition at 475–500°C. 100% of the organic C added was recovered by CHN analysis of untreated sediment, but after treatment with acid (necessary to remove carbonates from most sediments) only 0.19% and 1.32% of the C added could be recovered. Wet oxidation yielded only 76.6% organic C. Loss on weight after combustion in a muffle furnace yielded 100% of the total organic matter. It is very difficult to avoid carbonate interference if simple techniques of analysis are used. For most work by marine ecologists organic carbon and nitrogen may be measured by a combination of CHN analysis and loss of weight on ignition of sediments freed of organic matter by precombustion below 500°C.

A comparison of methods of determining organic carbon in marine sediments, with suggestions for a standard method

A baited camera has recorded a lysianassid amphipod that is twice as large as the largest amphipod previously recorded. The locality for this mobile omnivore is the sterile bottom of the eastern North Pacific Ocean, at a depth of 5304 meters.

Giant amphipod from the abyssal pacific ocean.

Summary

The paper summarizes observations on the pelagic distributions of sea-birds in Drake Passage and off southern South America, collected by ship-borne observers between December 1969 and April 1970, and in March and April 1972. The birds' distributions have been related to sea surface temperatures and, in the case of the Chilean fjords, to water types defined in terms of temperature and salinity; a partial attempt has been made to relate them to the distribution of the macroplankton.



The boundary between the ranges of Phalacrocorax albiventer and P. atriceps in the Chilean fjords is much farther west than previously reported, and there is some evidence that it has moved westwards within the last 20 years. It is suggested that its position is determined by oceanographic rather than climatic factors.



A sighting of Pterodroma macroptera in Cockburn Channel is the first record of this species for Chile. Exceptionally southerly records of Lobipes lobatus in Magellan Strait, and Pterodroma mollis south of the Antarctic Convergence are also described. An apparent decline in the numbers of Pterodroma neglecta at Masatierra, Juan Fernandez, is noted.

Summer seabird distributions in drake passage, the chilean fjords and off southern south america

Eleven species of Ampeliscidae (Amphipoda) occur on a deep-sea benthic transect between Massachusetts and Bermuda, Two species of Byblis and one of Byblisoides are newly described; Ampelisca uncinata Chevreux, Byb1i.s gaimardi (Kr@yer), B. sewata Smith, Haploops setosa Boeck, and H. n and new distributional or ecological information is given for Ampelkca aequicornis Bruzelius, A. agassixi (Judd), and A. declivitatis Mills. There is a rough taxonomic and ecological zonation of Ampcliscidac, with species of Ampelisca in shallow water, blind species of Byblis on the continental slope, species of Haploops on the slope extending into the abyss, and an endemic species of Byblisoides at fully abyssal depths which is adapted for feeding on largo quantities of abyssal sediments by having strongly-modified second antennae and massive antenna1 muscles. Bathyal species of Byblis and Haploops also appear to bc sediment or suspension feeders but are less strongly modified. Zoogeographic affinities of the species arc varied, especially on the continental slope. Shallow-water species are Virginian and Carolinian, outer shelf species may range to north or south (but not both), and the Byblisoides is endemic to the North American Basin. The bathyal species are widespread around the North Atlantic or closely related to species from the northeast Atlantic.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1971.16.2.0357

Deep‐sea amphipoda from the western north atlantic ocean. the family ampeliscidae1,2

Edward Forbes's colleagues recognized him as a talented invertebrate zoologist, a palaeontologist of note, a pioneer of biogeography, a clever, witty writer, and a thinker of a highly unusual stamp. Forbes's work and his memory have continued to intrigue biologists and historians of science for more than a century, but despite an extensive printed record Forbes remains puzzling. His philosophical approach to the natural world, which seemed anomalous to his eminent colleagues like Hooker, Darwin, Huxley, and Lyell, has remained an anomaly into the 1980s.

Eric L. Mills

Papers

A comparison of methods of determining organic carbon in marine sediments, with suggestions for a standard method

Giant amphipod from the abyssal pacific ocean.

Summer seabird distributions in drake passage, the chilean fjords and off southern south america

Deep‐sea amphipoda from the western north atlantic ocean. the family ampeliscidae1,2

A view of Edward Forbes, naturalist*