What determines the likelihood of species discovery in marine holozooplankton: is size, range or depth important?

The relationship between date of first description and size, geographic range and depth of occurrence is investigated for 18 orders of marine holozooplankton (comprising over 4000 species). Results of multiple regression analyses suggest that all attributes are linked, which reflects the complex interplay between them. Partial correlation coefficients suggest that geographic range is the most important predictor of description date, and shows an inverse relationship. By contrast, size is generally a poor indicator of description date, which probably mirrors the size-independent way in which specimens are collected, though there is clearly a positive relationship between both size and depth (for metabolic/trophic reasons), and size and geographic range. There is also a positive relationship between geographic range and depth that probably reflects the near constant nature of the deep-water environment and the wide-ranging currents to be found there. Although we did not explicitly incorporate either abundance or location into models predicting the date of first description, neither should be ignored.

Going Global: planning the next 80 years of the Continuous Plankton Recorder Survey

Going Global: planning the next 80 years of the Continuous Plankton Recorder Survey. Operated by the Sir Alister Hardy Foundation for Ocean Science (SAHFOS), the Continuous Plankton Recorder (CPR) survey is the world’s largest, sampling 4 ocean basins, and longest running (since 1931) plankton biodiversity monitoring programme. Having sampled enough miles to circumnavigate the globe over 200 times, the CPR database houses over 2.5 million entries, describing the distribution of 500 phytoplankton and zooplankton taxa. Routinely sampling in the Arctic, Atlantic, Pacific and Southern Oceans, the survey analyses 4000 samples yearly. Data collected from these samples are made freely available for bona fide scientific purposes. The CPR survey data is used to generate a better understanding of changes in the plankton and to date some 1000 papers have been published on plankton biodiversity. This year sees the 80th anniversary of the CPR survey and to celebrate and build upon this unique monitoring programme, SAHFOS intends to further develop its global plankton perspective. Work will be extended into the South Atlantic and Indian Ocean and an international partnership with complementary surveys in Australia, Canada, America, Japan and South Africa will be implemented. The Digital Object will describe the CPR survey using compilations made by Plymouth Art College and BBC film footage.

Maintenance of abyssal benthic foraminifera under high pressure and low temperature: some preliminary results

Abyssal benthic foraminifera have been maintained alive for periods of several weeks under laboratory simulated deep-sea conditions of high pressure and low temperature. In separate experiments, bacterial-sized fluorescent microspheres and three species of microalgae were supplied as food particles. Subsequent light and electron microscopy showed that the algae had been ingested by several foraminiferal species. Furthermore, the fine structure of the foraminiferal cytoplasm was well-preserved which indicates, along with the ingestion of algal food, that they had remained in a viable condition during the incubation. Other observations indicate that abyssal benthic foraminifera ingest naturally occurring photosynthetic cells carried to the deep-sea bed by rapidly sedimenting aggregates. The ability to keep foraminifera originating from depths exceeding 4000 m alive in the laboratory paves the way for the experimental investigation of some important issues in deep-sea biology and palaeoceanography.

Depth-related gradients in community structure and relatedness of bivalves and isopods in the Southern Ocean.

Despite increased research over the last decade, diversity patterns in Antarctic deep-sea benthic taxa and their driving forces are only marginally known. Depth-related patterns of diversity and distribution of isopods and bivalves collected in the Atlantic sector of the Southern Ocean are analysed. The data, sampled by epibenthic sledge at 40 deep-sea stations from the upper continental slope to the hadal zone (774 – 6348 m) over a wide area of the Southern Ocean, comprises 619 species of isopods and 81 species of bivalves,. There were more species of isopods than bivalves in all samples, and species per station varied from 2 to 85 for isopods and from 0 to 18 for bivalves. Most species were rare, with 72% of isopod species restricted to one or two stations, and 45% of bivalves. Among less-rare species bivalves tended to have wider distributions than isopods. The species richness of isopods varied with depth, showing a weak unimodal curve with a peak at 2000 – 4000 m, while the richness of bivalves did not. Multivariate analyses indicate that there are two main assemblages in the Southern Ocean, one shallow and one deep. These overlap over a large depth-range (2000 – 4000 m). Comparing analyses based on the Sørensen resemblance measure (presence/absence) and Γ+ (presence/absence incorporating relatedness among species) indicates that rare species tend to have other closely related species within the same depth band. Analysis of relatedness among species indicates that the taxonomic variety of bivalves tends to decline at depth, whereas that of isopods is maintained. This, it is speculated, may indicate that the available energy at depth is insufficient to maintain a range of bivalve life-history strategies