Abstracts from the 4th Zooplankton Production Symposium
Hiroshima, Japan. 28 May - 1 June 2007
Aguilera, V. and R. V. Escribano.
Reproductive responses of copepod species in the Chilean northern upwelling system: the role of the nanoplankton fraction (abstract).
The significance of nanoplankton food for the diet and reproduction of copepods is relatively unknown for the Chilean upwelling system. While several copepod species are omnivorous, the efficiency by which they can use nanoplankton food for reproduction has rarely been studied the nature. During the summer campaign 2006 of CENSOR WP-2 project, a series of experiments with Acartia tonsa and Centropages brachiatus fed on natural nanoplankton were carried out in two upwelling zones off Chilean northern: Mejillones Bay (23ºS) and Chipana Bay (21ºS). Copepod incubations were followed by periods of 48 hours at 15 ± 1ºC. Nanoplankton biomass and composition were established through epifluorescence microscopy techniques. The reproductive efficiency displayed by both species with the supplied food, was studied by mean the egg production rate (EPR), faecal pellet production rate (FPPR), ingestion rate (IR) and gross efficiency on egg production (GEEP). Six protist groups were identified and the food concentration was < 30 µg L-1. EPR varied between 0.3 and 0.5 µg C female-1 d-1; FPPR varied between 0.10 and 0.20 µg C female-1 d-1; IR varied between 0.06 and 0.13 µg C female-1 d-1 and GEEP always was > 60%. Despite the narrow dietary offer and low food concentration covered, these results showed that more than 50% of ingested carbon was invested in egg production and the nanoplanktonic diet was efficiently used by both copepod species, revealing a high metabolic plasticity to cope with a strongly variable food supply in this upwelling zone. (Poster)
Blanco-Bercial, L., A. Bucklin and F. Álvarez-Marqués.
Spatial population genetic structure and phylogeography of two species of the copepod genus Clausocalanus (abstract).
The copepod genus Clausocalanus includes widespread species that occur in every ocean and can be very abundant (and sometimes numerically dominant) in many places. Despite their overlapping distributions, the species are ecologically, biogeographically, and genetically distinct. The present study focuses on two species: the circumglobally distributed C. arcuicornis and the biantitropical C. lividus. DNA sequences for a portion of mitochondrial cytochrome oxidase I (mtCOI) were determined for individuals of different populations of each species. Multiple analytical approaches were carried out in order to analyse phylogeographic patterns and genetic population structure for both species. The results showed high haplotype diversity for both species, especially C. arcuicornis, and a lack of intermediate haplotypes. An hierarchical Analysis of Molecular Variation (AMOVA) revealed differences in population genetic structure between the two species: C. arcuicornis primarily exhibited variation within populations, whereas C. lividus primarily had variation among populations. Cluster analysis of Fst values between pairs of conspecific populations clearly showed differing patterns of genetic diversity for the two species. Phylogeographic analysis of spatial patterns of mtCOI haplotypes provided evidence of gene flow patterns, with differences between C. arcuicornis and C. lividus likely resulting from their biogeographical distributions.
Bucklin, A., R. M. Jennings, B. D. Ortman, L. Nigro, C. J. Sweetman, N. J. Copley and P. H. Wiebe.
DNA barcoding of marine zooplankton: a ‘Rosetta Stone’ for taxonomic and biodiversity studies (abstract).
The marine holozooplankton assemblage includes ~7,000 described species in 15 phyla. Taxonomic analysis of samples is time-consuming and identification of difficult taxa often requires the attention of experts. As part of a global survey of biodiversity, the Census of Marine Zooplankton (CMarZ) has determined DNA barcodes (i.e. sequences for short regions of DNA that discriminate species) for more than 1,500 zooplankton species and seeks to barcode all described species by 2010. The growing database of DNA barcodes will serve the function of a ‘Rosetta Stone’ for the zooplankton community, by associating a diagnostic DNA sequence with identified specimens and thus providing a new key to the cumulative knowledge of taxonomic experts. The DNA barcode database can be used to identify individual specimens and to identify species in unsorted samples. In the not-toodistant future, DNA barcodes will be used to fabricate DNA microarrays for use in automated taxonomic analysis of known species in zooplankton samples, thus freeing experts to focus on the identification and description of new species. Eventually, DNA microarrays may be used in remote and autonomous applications for characterisation of species diversity and biogeography throughout the world oceans.
Cazassus, F., C. L. Moloney, S. Tsotsobe and H. M. Verheye.
Changes in zooplankton community structure in the northern Benguela during 1978-1989 (abstract).
Zooplankton was analysed from ichthyoplankton-directed samples collected monthly at nine stations along a transect (5 nautical miles extending up to 65 nautical miles offshore) at 23ºS off Walvis Bay (Namibia) between 1978 and 1989. From this dataset, interannual variations of seasonal patterns of zooplankton community structure were studied, particularly during austral spring (upwelling season) and summer (warm and stratified water). The former season is characterised, in the coastal area, by high abundance and low diversity of zooplankton, and the predominance of Calanoides carinatus, whereas the latter season shows higher diversity and the presence of warm water indicator species such as Nannocalanus minor, Acartia tranteri and Temora turbinata. The distribution of the most abundant species (Calanoides carinatus, Metridia lucens, Centropages brachiatus and Rhincalanus nasutus) and their biogeographic role in the system are described. In 1984, a Benguela Niño occurred, which altered the zooplankton species composition and abundance in the area. Total copepod abundance during the ten-year study period appeared constant in spring, but summer abundances increased over time. Various taxa showed different patterns of abundance during different seasons; for instance, whereas the presence of M. lucens (characteristically more abundant at the shelf break) remained constant during the study period, C. carinatus (predominant in upwelled water inshore) was more abundant during the upwelling season and its presence, in summer, diminished over the years. (Poster)
Claramunt, G., S. Soto, P. Moreno, J. Mendez, K. Manríquez, L. R. Castro, P. Hidalgo and R. V. Escribano.
Variability of zooplankton community structure and biomass in the coastal upwelling zone of the Chilean Humboldt Current as assessed by ZOOIMAGE analysis (abstract).
Coastal upwelling systems exhibit strong spatial and temporal variability in plankton distribution. In order to examine such variability and its association with upwelling variation, we applied ZooImage analysis to zooplankton samples obtained at two upwelling sites off Chile, Iquique area (18-26ºS) and Concepción area (34- 37ºS). Samples obtained in the last 5 years covered coastal and oceanic zones (at variable spatial resolution) and intra-seasonal to inter-annual variation using Calvet, Bongo and Tucker Trawl nets. Some sets of samples were also analysed by traditional methods. The complete analysis allowed us to make comparisons between sampling methods and between analytical methods, as well as to examine the spatial distribution of zooplankton biomass and taxa over the continental slope and in oceanic areas. Temporally, upwelling is strongly seasonal off Concepción,whereas in Iquique upwelling is intermittent year-round. Zooplankton biomass and taxa, mostly represented by calanoid copepods and euphausiids, may respond to this upwelling variability as revealed by correlation with oceanographic variables most linked to upwelling, such as surface emperature, dissolved oxygen, and depth of the oxygen minimum zone. We concluded that the ZooImage software may offer a highly valuable analytical tool to assess and understand plankton variability in the coastal zone of highly productive upwelling systems.
Cornils, A., S. B. Schnack-Schiel, A. Baurle and C. Richter.
The impact of hydrographic parameters on the vertical and spatial distribution of calanoid copepod species on the shelf off SW Sulawesi (Indonesia) (abstract).
The coastal waters of southwest Sulawesi are characterised by an extensive shallow shelf covered with coral reefs and islands of the Spermonde Archipelago. The species composition and abundance of the calanoid copepods within this area were examined in relation to hydrography, nutrient concentrations and phytoplankton biomass. Sampling was carried out along four cross-shelf transects across the archipelago. Zooplankton was collected at each station from 3-4 depth layers in the upper 30 m during day by a vertically towed Apstein net (200 ?Êm). At all stations the majority of copepods were encountered below 10 m where the diversity was highest. In total, we have identified 71 calanoid copepod species. The number of species decreased from the offshore waters (23-30 species) to the coast (12-16 species). The species composition changed considerably from the near shore (15-40 m water depth) to offshore stations (>100 m). At the coastal stations mainly neritic species occurred (Acartia erythraea, Metacalanus aurivilli, Pseudodiaptomus aurivilli, Temora turbinata, Tortanus gracilis) while at the offshore stations more oceanic species were found (e.g. Clausocalanus spp., Canthocalanus pauper, Cosmocalanus darwini, Rhincalanus rostrifrons, Subeucalanus subcrassus, Candacia spp., Euchaeta media, Temora discaudata, Scolecithrix danae). The most abundant taxa at all stations were species of the Paracalanidae and especially the genus Paracalanus. The results will be discussed in relation to various environmental parameters such as temperature, salinity, nutrients and phytoplankton composition.
Davis, R. E., M. D. Ohman and J. T. Sherman.
Autonomous ocean gliders as a platform for continuous zooplankton observations (abstract).
New approaches are needed to sample zooplankton continuously over extended geographic areas, in order to resolve the mechanisms underlying zooplankton responses to climate and other sources of ocean variability. While a variety of optical, acoustical, and direct zooplankton sampling devices currently exist, present modes of instrument deployment have serious limitations. Shiptime is expensive and shipboard sampling with nets, pumps, profilers, or towed bodies is typically spatially restricted. Moorings resolve temporal, but not spatial variations. Conventional AUV’s often have restricted endurance. Improvements in deployment platforms are needed to significantly expand temporal and spatial characteristics of zooplankton sampling devices. Here we describe the use of Spray gliders, designed and built in the Instrument Development Group at Scripps, as a platform for deployment of instruments for zooplankton acoustic backscatter, CTD, and chlorophyll fluorescence. With this particular payload, the glider has an endurance of approximately 90 days, at which time it is remotely navigated close to shore and recovered with a small skiff. Two Spray gliders are currently sampling the southern sector of the California Current from nearshore to ca. 500 km from the coast. Data from vertical profiles to a depth of 500 m are telemetered via the Iridium satellite network immediately upon completion of each dive. Full two-way communications permit remotely-guided adaptive sampling in response to unexpected phenomena. Other instruments will be accommodated in the future. (Poster)
Escribano, R. V. and A. S. Araneda.
Combining time series data with spatial variability to study population dynamics of the large-sized calanoid copepod, Rhincalanus nasutus, off central/southern Chile (abstract).
Rhincalanus nasutus (Copepoda: calanoida) is a widely distributed species in the upwelling zone off central and southern Chile. Little is known about its life cycle or population dynamics in this highly productive ecosystem. We have used monthly time series data from Station 18 (36ºS) over the shelf, seasonal data from Station 40 in the offshore, and two large-scale oceanographic surveys carried out in the spring of 2004 and 2005 to assess the species annual life cycle, its seasonal and interannual variability and its mesoscale spatial distribution. All life stages were studied and stage-specific biomass was estimated. The population reached maximal abundances during the spring-summer period at Station 18, suggesting rapid growth under intense upwelling conditions. By late summer and early fall the population exhibited low abundances. The combination of data from the shelf and offshore stations, and the distributions observed in the large-scale grids indicates much of the temporal variability results from changes in spatial distributional patterns. Because of its large body size and abundance, this species may contribute substantially to zooplankton biomass and the carbon budget in the upwelling zone. (Poster)
Escribano, R. V., C. E. Morales, O. Ulloa, H. H. González, A. Araneda, V. Anabalón, K. Manríquez, P. Hidalgo, D. Böttjer, G. Alarcón, R. Riquelme, R. Giesecke, P. Mendoza, R. Riquelme, E. Menschel and C. Aparicio.
Plankton time series in the coastal upwelling off central-southern Chile (Station 18): driving forces on planktonic community structure (abstract).
Seasonal to inter-annual variability in coastal planktonic assemblages (abundance and biomass) is examined using data from the COPAS Center time series at Station 18 on the continental shelf in the upwelling ecosystem off Concepción, Chile (36° S). This fixed station is located within the highly productive zone subjected to seasonal wind-driven upwelling and river inputs. Nearly monthly sampling for autotrophic and heterotrophic pico-, nano- and micro-, meso and macrozooplankton were undertaken (2002-2006). The analyses showed both periodical and stochastic signals in the dominance of species/functional groups and different degrees of correlation between biological components and environmental forcing. Picoplankton (bacterioplankton, Synechococcus spp. and photosynthetic picoeukaryotes) exhibit a strong seasonal variability not in phase with total chlorophyll-a concentration. Nanoplankton was mostly composed by autotrophic cells, concentrated in the upper 30 m with no seasonal differences in abundance/biomass though maximum values appeared during upwelling, along with maximum integrated (0-80 m) chlorophyll-a (total and the <20 µm fraction). Microplankton was also concentrated in the top 10 m depth, dominated by diatoms and making substantial contributions to total biomass during the upwelling season, with maxima (also dinoflagellates and tintinnids) in the austral summer, together with maxima in total chlorophyll-a. Nitrate limitation does not explain the strong seasonal signal in micro-phytoplankton dominance or the suppression of co-existing nano-phytoplankton during upwelling. Meso- and macrozooplankton showed a strong annual signal, associated with depth of the oxycline. Neither, biomass or taxa abundance showed any correlation with temperature or phytoplankton biomass, whereas C and N contents varied accordingly with changes in taxa. Greater C/N ratios occurred upon dominance of copepods and the average C content of zooplankton was 40%. The study provides baseline information to assess the impact of El Niño, or other large scale variability on the planktonic community of this upwelling system. (Poster)
Finenko, G. A., Z. A. Romanova, G. I. Abolmasova, B. E. Anninsky, T. V. Pavlovskaya, L. Bat and A. Kideys.
Ctenophores - invaders and their role in trophic dynamics of the planktonic community in the coastal regions off the Crimean coast of the Black Sea (Sevastopol Bay) (abstract).
The Black Sea is an impressive model of the damaging impact of invasive species on the ecosystem as a whole and on the planktonic community in particular. The introduction of the ctenophore M. leidyi in the late 1980s resulted in a dramatic decrease in both the abundance of some species and in biodiversity of the zooplankton community. Competition between M. leidyi and planktonic fish for zooplankton prey brought about a remarkable decline in the fish stock. The appearance of a new invader ctenophore Beroe ovata, a feeder on Mnemiopsis at the end of the 1990s caused further changes in the planktonic community. In our work we discuss the seasonal and interannual dynamics of the two introduced ctenophore species monitored along with meso- and microzooplankton in the inshore waters of the northern Black Sea from 2000 to 2006. The B. ovata appearance resulted in M. leidyi biomass sharply falling to extremely low values and shortening time of M. leidyi presence in plankton. The predatory pressure of M. leidyi on the meso- and microzooplankton communities (evaluated by undertaking both field and laboratory studies of the main physiological characteristics) decreased much in those years. M. leidyi population consumed daily from 1.9 ± 0.4 to 13.4 ± 5.7% of mesoplankton biomass while these values were as high as 30–40% when B. ovata was absent. Maximum daily grazing rate of microzooplankton biomass by M. leidyi larvae was as much as 40% in Sevastopol Bay in the years of high abundance. The consequence of B. ovata invasion was positive for the recovery of the Black Sea planktonic communities and the ecosystem as a whole.
Giesecke, R., H. E. González and R. V. Escribano.
What determines the success of Sagitta enflata as a major zooplankton predator in the Humboldt Current System? (abstract).
This study is based on 3-years of monthly zooplankton sampling at a fixed point off Concepción (36°S) Chile. Reproduction of the chaetognath, Sagitta enflata, and its predation pressure upon zooplankton standing stock were assessed. Prior tonet tows, water temperature, conductivity and oxygen were measured with a CTDO profiler and microzooplankton samples were collected, in order to account for prey available for S. enflata offspring. All S. enflata specimens were measured and assigned to a maturity stage, and ingested prey were identified up to species level. Sagitta enflata accounted on average for 60% of total chaetognath abundance. The number of prey per chaetognath was highly variable during the whole period. It was lowest during upwelling events due to the rise of oxygen depleted water, with low removal rates of copepod standing stock (0 to 7% d-1), whereas above 4 ml O2 L-1 the removal rate increased exponentially up to 43% d-1. High removal rates are achieved by juvenile S. enflata that dominated between 45 and 60 days after reproduction. The sexual maturation process occurred during spring and summer once the phytoplankton bloom was established. The appearance of mature chaetognaths was coupled with an intensification of predation pressure upon Calanus chilensis, which might be essential for the maintenance of growth of chaetognath eggs by allowing higher lipid content, as compared to others copepod prey potentially available, such as Paracalanus parvus, Centropages sp., Acartia tonsa and Oithona sp. Once S. enflata reproduces and the phytoplankton bloom reduces in intensity, many nauplii were available for S. enflata offspring. Adequate adjustment between prey life cycle and S. enflata reproduction and spawning would be one of the main factors determining the dominance of these organisms in a highly heterogeneous habitat such as the coastal upwelling zone of the Humboldt Current.(Poster)
Hay, S., S. Robinson, J. Fraser, J. Rasmussen, K. B. Cook, J. Dunn, M. Heath, E. Bresnan, S. Fraser, D. Lichtman and M. Rose.
Zooplankton community description and comparison of seasonal population development for common species and groups, sampled weekly at time series sites on the Scottish east and west coasts (abstract).
Two Scottish coastal sites are sampled weekly for meso-zooplankton, phytoplankton, temperature, salinity and inorganic nutrients. The first site is 3 km offshore off Stonehaven on the east coast, sampled since January 1997, and the second is at a sea loch (Loch Ewe) on the northwest coast, sampled since April 2002. We describe here the zooplankton communities at these sites and the seasonal development of major species and groups against the background of environmental seasonality. We compare data from the two sites and consider the interannual variability in seasonal timing and abundance of key species. (Poster)
Hidalgo, P., E. Jorquera, P. Mendoza and R. V. Escribano.
Diel vertical distribution of zooplankton as constrained by the upper boundary of the oxygen minimum zone at the coastal upwelling region off northern Chile (abstract).
A shallow (<50 m) oxygen minimum zone (OMZ) is a prominent feature in the coastal zone off northern Chile. The zooplankton community must cope with this oxygen-deficient water. We have found from day/night stratified Multinet samples taken during the ZOMEI cruise (October 2005, northern Chile) that the whole zooplankton community is mainly comprised by copepods (>50%), with many species whose vertical distribution and diel migration appears to be restricted to the upper 50 m layer where there are strong vertical gradients in temperature, salinity and dissolved oxygen. Few species seem able to inhabit the OMZ either temporarily or permanently. Calanoid copepods, such as Paracalanus parvus, Acartia tonsa, Eucalanus inermis and Centropages brachiatus were the dominant species at two study sites. Short-term variability in oceanographic conditions was considered to determine the extent to which populations can perform vertical movements given the OMZ constraint. A negative relationship between numerical abundance and the number of species became evident when comparing sampling sites. The OMZ system may impose major ecological consequences for the zooplankton community in this upwelling region.(Poster)
Hopcroft, R. R. and K. O. Coyle.
Inter-annual variations of zooplankton in the northern coastal Gulf of Alaska (abstract).
The Seward Line in the Northern Gulf of Alaska has been the focus of multidisciplinary sampling for the past 9 years. We report on the observed inter-annual variations in the zooplankton community and its relationship to climatic influences. Over the study period we have observed years favorable and unfavorable to the local zooplankton species (e.g. a 5 fold range in Neocalanus plumchrus/flemingeri), and observed the summer import of southern species during warm years (e.g. Calanus pacificus, Mesocalanus tenuicornis, Paracalanus parvus). Surprisingly, even some subarctic species (e.g. Calanus marshallae, Limacina helicina) appear to do better during many warmer springs. Differences in temperature, along with chlorophyll, drive growth and reproduction of the zooplankton. This has consequences for the annual progression of the Neocalanus populations that dominate the spring, and the smaller species, such as Pseudocalanus, that dominate the summer zooplankton communities.
Kosobokova, K. N. and R. R. Hopcroft.
Population structure and reproduction of the chaetognath Eukrohnia hamata in the Canada Basin, Arctic Ocean (abstract).
Population size structure, vertical distribution and parameters of reproduction of the chaetognath Eukrohnia hamata were studied in the Canada Basin of the Arctic Ocean during the summer of 2005. Analysis was based on stratified zooplankton collections covering the depth range from 3000 m to the surface. Individual length ranged from 2.5 to 38 mm. Younger juvenile specimens <10 mm comprised ~80% of the population, while specimens >20 mm contributed only 5%. Size of the mature specimens, carrying 2 ovoid egg-sacs within the marsupium, varied between 27 and 36 mm. The chaetognath was encountered throughout the Arctic surface water layer and Atlantic water down to 1000 m depth, but not deeper. Specimens with eggs and embryos in the marsupium, and the smallest young specimens of 2.5-3 mm, were found mostly between 500 and 750 m depths. Juveniles of 4-10 mm length showed a clear preference for the layer between 100 and 500 m suggesting the upward ontogenetic migration of the growing specimens to strata with richer prey densities. Number of eggs and embryos in egg sacs of mature specimens varied from 50 to 137 with a maximum of 266 eggs and embryos per specimen. Embryonic development was examined and documented from the egg stage to hatching for the first time.
Kreiner, A., H. M. Verheye and R. Cloete.
Spatial and temporal variability of the copepod community along a monitoring transect in the northern Benguela during 2000-2006 (abstract).
Zooplankton has been collected regularly along a 70 nautical mile-transect off Walvis Bay (23°S) since February 2000. Copepods were numerically the most abundant mesozooplankton. Their abundances increased at the beginning of the time-series reaching a peak in 2004 and declining sharply after that. Copepod abundance showed a seasonal cycle with abundances at their lowest during austral winter (May to August), increasing after the onset of upwelling in September and reaching highest values during summer (November to February). Strong interannual variability in seasonality and abundance, however, did occur throughout the time-series. The dominant calanoid copepod species were Metridia lucens, Calanoides carinatus, Centropages brachiatus, Rhincalanus nasutus and Calanus spp. C. carinatus occurred mainly on the shelf, with highest abundances during peak upwelling, whereas M. lucens was more evenly distributed along the entire transect with highest abundances occurring between October and February. Calanus spp. only appeared in high numbers since the summer of 2005/2006 and subsequently dominated the calanoid copepod community during almost every month of sampling. The spatial distribution along the transect varied greatly throughout the time-series. During the austral summers of 2001/2002 and 2003/2004 copepods were mainly concentrated in the shelf areas, whereas during all other years they were distributed along the entire transect. The observed temporal and spatial variability in copepod abundance and community structure will be discussed in relation to the hydrography. (Poster)
Machida, R. J., M. Nishida and S. Nishida.
Zooplankton community genomics (abstract).
Impacts of human activities on the environment are of growing concern to society, with biodiversity disturbance being one of the most important issues. However, our understanding of biodiversity, especially in the ocean ecosystem, is very limited and difficult to asses with the current available information. In this context, we need further detailed information to evaluate biodiversity changes in the ocean ecosystem with accurate species identification, recognition of population structure, and genetic diversity. In this respect, we are carrying out an experiment called “Zooplankton community genomics”. We focus on zooplankton, because they occupy a vital role in the pelagic realm of the world ocean ecosystem since they transfer energy and matter produced by unicellular algae to higher trophic levels. They are known to occur in all marine habitats, throughout the vertical and horizontal pelagic realms. Despite such importance of zooplankton in the ocean ecosystem, it is difficult to understand their comprehensive biodiversity, because of fragility, rarity, small size, and systematic complexity of many taxa. We are currently applying molecular genetic techniques to answer this question.
Madin, L. P.
Gelatinous grazers: an underestimated force in ocean carbon cycles (abstract).
The biological carbon cycle in the ocean begins with photosynthetic fixation of carbon dioxide into phytoplankton cells, which are consumed by a variety of grazers. While some grazers, particularly microzooplankton, respire and recycle the carbon near the surface, many larger metazoan grazers transport significant portions of ingested C to deeper ocean strata by vertical migration, as rapidly sinking faecal pellets, or both. Gelatinous grazers, particularly pelagic tunicates are often more effective in this transport than other kinds of zooplankton, due to their high feeding rates, large population sizes, and dense, rapidly sinking faecal pellets. Epipelagic salps can occur in huge populations over large areas, consuming and sedimenting tons of C daily from the surface to deeper waters. At midwater depths, salps are rare, but doliolids and appendicularians are often abundant, collecting food with internal or external filters and producing both faecal pellets and discarded mucous houses. Other gelatinous particle feeders, including planktonic holothurians, polychaete worms and pteropods, are even less well-known than the tunicates. The activity of these grazers has consequences both for the food supply to the deep sea and benthos, and for the removal of C from the ocean-atmosphere equilibrium. When faecal pellets sink deep into the bathypelagic zone the carbon they contain may be consumed and respired by deep-living organisms, but it will not be returned to surface waters for thousands of years, and effectively removes it from equilibrium with atmospheric CO2. This natural sequestration of C by zooplankton has been occurring for millions of years.
Melle, W., J. Assmus and C. T. Å. Broms.
Diversity, seasonal cycles and recruitment processes of zooplankton in coastal and oceanic waters in relation to environmental variability; a time series study at a standard section off western Norway (abstract).
Data on zooplankton abundance, chlorophyll, nutrients, temperature and salinity was collected from 1993 to 2006 at 17 stations on Svinøy standard section heading northwest from the Norwegian coast at about 62°N. Zooplankton was sampled by vertical net hauls from 200 m to the surface. Samples were fixed in formalin and analysed taxonomically under the microscope. Samples for chlorophyll and nutrients were taken at standard depths, using a rosette sampler on a CTD, and analysed according to routine analytical procedures of the IMR. Coastal and Oceanic Atlantic water masses showed distinct diversity and interannual variability. During recent years with warming, smaller and more abundant warm water taxa with a different phenology have been introduced in both water masses. Increased abundance of the warm water species, Calanus helgolandicus, relative to C. finmarchicus was observed after 1995. The major contributor to zooplankton biomass, C. finmarchicus, does not overwinter in coastal water. Comparative population dynamic studies and timing of seasonal cycles of Atlantic and coastal stocks of C. finmarchicus showed that spring production of C. finmarchicus in coastal water relies on advection of G0 from the oceanic stock. High recruits to parental stock ratio in coastal water indicates higher recruitment success in this water mass and lower winter survival. Long-term variability in phenology and abundance is related to seasonal dynamics of the phytoplankton, and to variability in climate and physical oceanography. Timing and magnitude of production of eggs and nauplii in Norwegian coastal waters is essential for recruitment success of cod and herring.
Nair, V. R.
Phenomenal changes in chaetognath community of the Andaman Sea, Indian Ocean (abstract).
Vijayalakshmi R. Nair
National Institute of Oceanography, Regional Centre, PB No.1913, Kochi-682018, Kerala, India. E-mail: vijayalakshmi40-at-hotmail.com
The sea around Andaman Island is one of the prominent biodiversity hotspots in the Indian Ocean. This coral ecosystem
with luxuriant fringing coral reefs supports a rich and diverse fauna. Comparative evaluation of zooplankton samples
collected around the Andaman Seas during the North East (NE) monsoon period (November to February) of 1963,
1979 and 2005 shows glaring changes in the population density and community structure of Chaetognatha. In 1963
the average population of chaetognath was 20 m-3, which decreased to 7 m-3 in 1979 and further reduced to 4 m-3 in
2005. During 1963 chaetognaths were represented by 10 epipelagic species with predominance of Sagitta enflata
and S. pacifica. Thirteen epipelagic species were found in the collections of 1979 and S. enflata continued to be the
most abundant group and a few rare species encountered in the 1963 collections became abundant. Recent sampling
around Andaman Seas in 2005 showed enhancement in the number of species to 18 (including 2 new species). Also,
the community structure of chaetognaths showed drastic changes due to surfacing of meso and bathypelagic species
like Sagitta decipiens, S. lyra and Eukrohnia fowleri. Though Sagitta enflata was the common species, S. dicipiens, a
mesopelagic species became dominant at 150-300 m depth in the water column. Krohnitta pacifica, S. neglecta and
S. regularis became very common in the area. Such variability in the community structure of chaetognaths could be
explained by physical factors. Recurrently occurring severe cyclones in the Bay of Bengal during the NE monsoon
season and associated strong surface winds cause lateral stirring leading to upward movement of deep waters species. (Poster)
Nair, V. R.
Role of zooplankton in pollution monitoring: case studies along the west coast of India (abstract).
The most characteristic feature of zooplankton is its variability over space and time. Because of such inherent variability, it has been debated whether zooplankton can be used as an index to evaluate the impact of pollution. Environmental impact assessment studies conducted during 1990-1999 along the west coast of India indicate that a systematic evaluation of variations within the zooplankton can provide reliable information on pollution stress. Alterations in biomass and abundance of zooplankton beyond the natural fluctuations provide clues to unfavourable water quality. Variations in zooplankton biomass and abundance in a polluted creek are much greater than those observed in an unpolluted area. Species diversity and community structure of groups like copepods and chaetognaths give reliable indices of pollution load. Copepod species like Acartia spinicauda, Bestiolina similis, Paracalanus crassirostris, and Canthocalanus pauper are tolerant to pollution stress. Chaetognaths, very sensitive to environmental stress, showed increased population density and species diversity in the clean environment. Morphological changes in the chaetognath species Sagitta bedoti were observed in highly polluted environments. In the polluted creeks of Mumbai, the ratio between carnivores and herbivores increased to 40% compared to the normal 10%. Trophic conversion efficiency of 10% is also not attained in polluted environments. Concentrations of Cu and Zn in major groups of zooplankton were relatively low in the offshore area compared to the polluted creek environment. In general, these observations suggest that the deleterious effects of pollutants need to be evaluated quantitatively as well as qualitatively.
Nishikawa, J. and S. Nishida.
Mesozooplankton in the Sulu Sea and its adjacent waters with special reference to copepods (abstract).
The Sulu Sea (SS) is located in the western equatorial Pacific and is a semi-enclosed basin, rimmed by sills shallower than ca. 400 m. This sea has homogeneous and unusually warm (ca. 10°C) water from the mesopelagic zone to the sea bottom, while the adjacent Celebes Sea and the South China Sea show more ‘normal’ oceanic conditions. Under these contrasting settings, the relationships between vertical water-column structure and biomass, biodiversity and patterns of vertical distribution of mesozooplankton were examined. The total mesozooplankton biomass in the mesopelagic layer, the degree of exponential decrease in their biomass and abundance with depth, the vertical distribution patterns of higher taxonomic groups, and community structure analysis using a dissimilarity index applied to higher taxa, all indicated no significant differences between the seas. This suggests that warm mesopelagic water in the SS does not drastically influence the mesozooplankton standing stocks, vertical distribution patterns and the community structure at the higher taxonomic levels. However, the composition of copepods was markedly different in the calanoid families between the SS and the Celebes Sea, with dominance of Eucalanidae, Metridinidae, and Lucicutiidae in the layer of lower dissolved oxygen in the SS. Reduced abundance in the dominant genera such as Euchaeta, Mormonilla, and Conaea was also observed in the SS. Among the > 300 species identified, 5 possible new species were found only in the mesopelagic water of the SS, suggesting the existence of unique communities at lower taxonomic levels (genera and/or species) in the SS.
Nonomura, T., R. J. Machida and S. Nishida.
Vertical distribution of Calanus sinicus and C. jashnovi (Copepoda: Calanoida), based on genetic identification, in Sagami Bay, central Japan (abstract).
Genetic differentiation among Calanus sinicus collected from Sagami Bay, central Japan, adjacent to the Kuroshio Current, Calanus jashnovi from the Kuroshio Extension region and Calanus pacificus from the Oyashio region were examined for mitochondrial srRNA and nuclear ITS I and ITS II genes, using adult females (C6) which are morphologically distinguishable. The highest levels of genetic differentiation among species were observed at srRNA, followed by ITS I and ITS II. The intraspecific genetic distance of srRNA within C. sinicus (0.000-0.002) was lower than the interspecific genetic distance (0.119-0.149), indicating that DNA sequences of these gene loci are consistent with the morphological differences among species, providing a basis for identification of immature specimens. Vertical distribution of Calanus species throughout all copepodite stages was investigated in Sagami Bay in May 2006, based on stratified sampling in the upper 1000 m. On the basis of the genetic markers, 22 individuals analysed were allocated into C. sinicus or C. jashnovi that were also distinguished by the prosome length (PL). Most individuals of C. sinicus were found in the 0-50 m layer; however, C5 of C. sinicus of ca. 2000 ìm PL were also observed below 200 m. While C5 of C. jashnovi of ca. 2500 ìm PL were distributed below 600 m, the other stages of C. jashnovi were almost absent throughout the water column. These data suggest that C. sinicus and C. jashnovi are able to diapause at C5.
Nonomura, T., R. J. Machida, J. Nishikawa and S. Nishida.
Life histories of Calanus sinicus and Calanus jashnovi (Copepoda: Calanoida) in the 1000 m water column of Sagami Bay, central Japan (abstract).
Seasonal changes in abundance, development and vertical distribution of Calanus sinicus and C. jashnovi were investigated in Sagami Bay, central Japan on the basis of monthly stratified sampling in the 1000 m water column from May 2002 to January 2004. Calanus sinicus showed a biphasic life history at copepodite stage 5 (C5). All copepodite stages of C. sinicus occurred in the 0-200 m stratum throughout the year, with seasonal and annual variation in abundance. At the same time, some C5 showed a diapause below 200 m from spring to autumn. Integrated individual numbers of the diapausing C5 per m-2 in the 200-1000 m stratum were 2640-3728 (average 3040) in May-June, 5792 in July, 3872-6112 (average 5355) in September-October, and 0-368 (average 135) in November-February. Thus, the population built up in the stratum below 200 m from spring to summer, was constant during autumn, and emerged from diapause and matured in early winter. Calanus jashnovi showed a diapause at C5 in the stratum below 400 m during May to January and did not show a biphasic life history like that of C. sinicus. Female and male C6 of C. jashnovi appeared in the 200-400 m stratum in February, and then a new generation of C5 and C4 was observed at 0-200 m in March. However, since the other early copepodite stages did not occur in any season, C. jashnovi probably does not complete its life cycle in Sagami Bay.
O’Brien, T. D., D. L. Mackas, H. M. Verheye and r. W.-. members.
SCOR WG-125: Global Comparisons of Zooplankton Time Series (abstract).
The SCOR Working Group on Global Comparisons of Zooplankton Time Series (WG-125) was formed to promote between-region comparisons of longer zooplankton time series from around the globe. With data contributions and participation from 12 countries, over twenty long term regional zooplankton time series have been identified, and data from these regions have been collated and prepared for further numerical analysis. Within many regions, substantial long term shifts in the zooplankton biomass, species abundance, community composition, and/or seasonal timing are already evident (factor of 5-100 for the “amount” time series, 0.1-0.2 years for the seasonal timing). Work has begun to compare these changes across and between regions, looking for evidence of temporal synchrony and large scale spatial teleconnection among the zooplankton time series and also with time series of climate and fishery indices. This work reviews the participants and time series of SCOR WG-125 and presents some of the initial results of our analyses. (Poster)
Ohman, M. D. and C.-H. Hsieh.
Spatial domains of increased mortality of Calanus pacificus within the California Current System (abstract).
The Vertical Life Table method (Aksnes and Ohman, 1996) was used to estimate patterns of mortality of late developmental stages of Calanus pacificus in the southern sector of the California Current System (CalCOFI region). The stage-specific copepod enumerations utilised in this study were published by the late M.M. Mullin or by G.A. Rebstock, based on samples taken on 7 CalCOFI cruises (3 spring, 4 late autumn-early winter). Stage ratios were available from 9-52 stations per cruise. The durations of copepodid stages IV and V were described as a continuous function of both food concentration and temperature from a re-analysis of Vidal’s (1980) experimental rearing of Calanus pacificus. This function was combined with in situ vertical profiles of temperature and chlorophyll a concentration to estimate stage durations in the field and solve for the instantaneous mortality rates of two stage pairs: CV/adult females and CV/adult males. Male mortality rates averaged 2-3 times higher than corresponding female mortality rates. There was no significant difference between seasons (spring vs. late autumn) in either male or female mortality rates. However, there was a consistent spatial pattern of higher mortality rates of both males and females in the inshore region relative to the offshore region (P < 0.05). This inshore increase in mortality rates is inversely related to food limitation, but directly correlated with an index of abundance of zooplanktivorous fishes obtained from the CalCOFI ichthyoplankton series (a fishery-independent data source). Elevated predation risk may mitigate the inferred benefits to zooplankton of increased food supply.
Ohman, M. D., G. H. Rau, P. Hull and A. Pierrot-Bults.
Zooplankton stable N isotopes as an index of climate variation in the NE Pacific (abstract).
We have analysed the long-term (>54 year) variability in zooplankton 15N/14N isotopes in two sectors of the California Current System (CCS): Southern California (Pt. Conception to the Mexican border) and Central California (centred on the Monterey Bay area), utilising the extraordinary CalCOFI zooplankton collection. We use zooplankton stable N isotopes to assess the spatial coherence of food web responses in these two geographically different, but interconnected regions of the CCS. We address the sensitivity of pelagic food web structure to climate forcing on multiple time scales: El Nino, multi-decadal variability, and the long-term warming trend. Toward this end we have focused on four zooplankton species: the particle-feeding copepods Eucalanus californicus and Calanus pacificus and the obligately carnivorous chaetognaths Sagitta bierii and S. euneritica, all of which were found in both regions in nearly all study years. Three of the four species exhibit an El Nino-related enrichment in heavy N in both geographic regions. The remaining species (E. californicus) does not respond in a consistent manner to El Nino and other interannual variations, but shows a secular decline in delta15N. We consider the possibility that a progressive deepening of this species' habitat, combined with a long-term change in NO3 concentration in source waters for upwelling in the California Current, may be responsible for the observed changes.
Pillai, H. U. K., C. K. Shiju, S. U. Panampunnayil, V. R. Nair and C. B. L. Devi.
Community structure and diversity of zooplankton in the Mahatma Gandhi Marine National Park, Wandoor, South Andaman, Indian Ocean (abstract).
The tsunami of December 2004 caused extensive damage to the coastal regions of southern Andaman and the Nicobar Islands. The Mahatma Gandhi Marine National Park at Wandoor was hard hit by the tsunami and the coral reefs and other habitats were extensively damaged. Community structure and diversity of zooplankton in relation to environmental parameters of Mahatma Gandhi Marine National Park were studied during the winter monsoon (WM; February, 2005) and inter monsoon (IM, May, 2005) periods. Though the variation in zooplankton biomass between the two seasons was negligible (WM - average 7.94; IM - 6.95 ml/100m3), the population density was significantly lower during the winter monsoon (WM- average 16018; IM - 28704 no./100m3). Copepods formed the dominant group (77-81%) during both seasons whereas other groups showed variation in dominance rank. The copepod community was represented by 43 and 33 species during the winter and inter monsoon respectively. A total of 8 species of Chaetognath were observed during WM and 5 species during IM of which Sagitta enflata, and S. neglecta were the most abundant. Abundance and species diversity of other major groups will also be discussed. In general the area supported a moderately rich zooplankton community. (Poster)
Reid, P. C.
The importance of zooplankton in reducing levels of atmospheric CO2 via the biological pump (abstract).
Zooplankton play a key role in climate change through the transfer of large quantities of CO2 to the deep ocean by a process known as the biological pump. Plankton composition is crucial as associated mineral material facilitates sinking of carbon rich debris and some taxa package faecal and detrital material. Ocean acidification may impact calcareous groups. Zooplankton have also been shown to be highly sensitive indicators of environmental change. Results will be presented to show that ocean temperature, circulation and planktonic ecosystems (using data from the Continuous Plankton Recorder, CPR survey) in the North Atlantic are changing rapidly in concert and that there is evidence to suggest that the changes are an ocean wide response to global warming with potential feedback effects. Given the importance of the oceans to the carbon cycle, even a minor change in the flux of carbon to the deep ocean would have a big impact increasing growth of atmospheric CO2. We have virtually no understanding of the spatial and temporal variability in the efficiency of the biological pump for most of the world’s ocean. Establishing new plankton monitoring programmes backed up by appropriate research to help understand processes is needed to address this gap in knowledge. There is little doubt within a global change context and the future of mankind that a potential acceleration in the growth of atmospheric carbon due to a reduction in the efficiency of the biological pump is a key issue for future research in zooplankton ecology.
Schnack-Schiel, S. B., F. J. Sartoris, A. Cornils, S. Papadimitriou and D. N. Thomas.
Life strategies of dominant Antarctic calanoid copepods in late winter/early spring (abstract).
The life cycles of Antarctic copepods are all well timed to the distinct annual periodicity in primary production. However, our knowledge in particular of the transition time from winter to spring is not yet complete and studies especially on physiological and biochemical adaptations are extremely rare. In September-October 2006 we studied the life strategies of calanoid copepods in the Scotia and Weddell Seas. The investigations included the vertical distribution, age structure, feeding, respiration, excretion, lipids, C:N and ion regulation. In September, a winter situation was encountered with a maximum in abundance at greater depths: the bulk of the copepod Calanoides acutus was concentrated below 1000 m and CV dominated. The specimens showed no or very low ingestion as well as very low respiration and excretion rates indicative of overwintering conditions. In contrast, Calanus propinquus occurred in upper waters and was clearly feeding. Six weeks later, in mid October, a spring bloom had developed in the Scotia Sea and C. acutus had left the winter quarters at depth and returned to the highly productive surface. Experiments revealed high ingestion, respiration and excretion rates. Interestingly, both C. acutus and Rhincalanus gigas had large amounts of ammonium in the haemolymph. This phenomenon was not detected in the other copepod species studied. The significance of these findings will be discussed with respect to the life strategies of the species and relationships to environmental parameters.
Stephen, R., V. R. Nair, K. V. Jayalakshmy, G. Karlekar and S. N. Gajbhiye.
Diminishing density and diversity of copepods in the semi-enclosed docks of Mumbai Port, west coast of India (abstract).
Ports and harbours are areas of intense human activities. Periodic dredging and disposal of waste in the harbour environment alter its physical and chemical properties. Constructions to provide dock facilities result in enclosed and semi enclosed water bodies, the biology of which has received little attention. The present study examines the physical properties, water quality, relative dominance and diversity of planktonic copepods from 29 locations within the Mumbai Port. The stations cover major docks, minor docks and bunders during postmonsoon (November 1996) and premonsoon (May 1997) periods. The copepod communities in these enclosed and semi-secluded water bodies are considered and are compared with the populations at 13 stations in the open ocean area adjacent to Mumbai Port, a natural harbour. The average percentage contribution of copepods to zooplankton was 57.5% in the open ocean, while in the docks it was 88.3%. The average population density of copepods in the open ocean (12506/100 m3) was 7 times higher than that of the docks (1744/100 m3). In the open ocean 23 species occurred during premonsoon with Acartia spinicauda and Acrocalanus sp. as the main contributors. During postmonsoon, 22 species were obtained and Acartia spinicauda and Canthocalanus pauper dominated. The density was low in the docks with minimum values during post monsoon. The number of species recorded at Indira, Victoria and Princess docks were respectively 13, 9 and 10 during premonsoon and 6, 6 and 9 during postmonsoon. Pseudodiaptomus sewelli, Paracalanus aculeatus, Acrocalanus longicornis, Pseudodiaptomus serricaudatus and Onacea sp. were the main components in the docks. In the Sasson dock located at the harbour entrance, 17 species were present during premonsoon but only 7 species were recorded during postmonsoon. Statistical interpretation for niche breadth and for differential factor groups of species was also attempted. The study showed a reduction in density and diversity of copepod population in the docks as compared to the open ocean. Limited flushing within the docks could be an adverse factor controlling the copepod community, so that only the tolerant species like Pseuododiaptomus spp. flourish.
Vargas, C. A., J. L. Iriarte, R. Martínez, P. Contreras, C. Valenzuela, L. A. Cuevas, C. Cartes, D. Opazo and R. V. Escribano.
Food web structure and carbon flows in a river-influenced and non-river influenced continental shelf at the coastal upwelling area off Central Chile (36°S): importance of mixotrophy and omnivory
(abstract).
Classical and microbial pathways remain as a useful dichotomy for distinguishing the several fates of primary production in aquatic ecosystems. In most of our idealised concepts of food web, we tend to separate profoundly between the photosynthetic and the heterotrophic organisms in the predatory food web. This division is not necessarily adequate descriptions of reality since there are known organisms able to combine nutrition types, and complicate our traditional view about aquatic food webs. One complicating factor that is receiving increasing attention is the influence of ‘mixotrophs’, organisms that defy traditional trophic classification concepts by both photosynthesizing and grazing. In addition, ‘omnivory’, the consumption of resources from more than one trophic level, is a widespread behaviour among planktonic organisms. Evidence for shifting trophic roles of various types of planktonic organisms and multiple levels of feeding interactions within mixotrophs and omnivorous components, which typically have been regarded as a single trophic level have increased during the last decade. By using field and experimental approaches, we propose to elucidate the potential role of ‘mixotrophy’ and ‘omnivory’ to the carbon flows in a river-influenced and non-river influenced continental shelf off Central Chile. Primary production, bacterial production, autotrophic, heterotrophic and mixotrophic biomasses, as well as, measurements of grazing
by nanoflagellates, microzooplankton, and mesozooplankton are conducted under contrasting conditions during spring and winter. Ongoing food web analysis of the spring condition during coastal upwelling events, and under the influence of the river discharge will be discussed, as well as, the implications of mixotrophy and omnivory in the structure and ecosystem functioning.
Funded by FONDECYT Project 1060709 (CONICYT-Chile)
Verheye, H. M., F. Cazassus, A. Kreiner, S. Tsotsobe, T. Mainoane, R. Cloete and F. Kotze.
Long-term changes in abundance and community structure of copepods in the northern Benguela upwelling system off Namibia, 1950s-present (abstract).
A multi-decadal zooplankton time-series for a transect off Walvis Bay (23°S), Namibia in the northern Benguela Current system was reconstructed from a number of data sources. These included: (i) published literature for 1959 and 1972, (ii) retrospective analysis of samples collected during monthly ichthyoplankton surveys in the late 1970s and the 1980s, (iii) an unpublished manuscript for 1997, and (iv) ongoing analysis of samples collected during Namibia’s current environmental monitoring programme since February 2000. Despite some methodological differences (especially with respect to sampling gear, mesh size, and sampling depth), data gaps and substantial interannual variability, there is evidence to suggest that, similar to the southern Benguela off South Africa, zooplankton in the northern Benguela has increased markedly over the past five decades. Coastal zooplankton biomass off Walvis Bay has increased by about one order of magnitude since 1959, and the total number of copepods has increased >5-fold over the past three decades. Long-term trends in the abundance of dominant copepod species (Calanoides carinatus, Calanus spp., Centropages brachiatus, Metridia lucens, Oithona spp., Rhincalanus nasutus) are examined and indicate decade-scale changes in community structure.
Viñas, M. D., A. Bucklin, H. M. Verheye, J. G. F. Bersano, S. Ceballos and W. M. Ribas.
Taxonomic and phylogeographic comparisons of Calanoides carinatus (Copepoda, Calanoida, Calanidae) from the Atlantic Ocean (43ºN-47ºS) (abstract).
Calanoides carinatus inhabits the Atlantic and Indo-Pacific oceans and the Mediterranean Sea. In highly productive areas this species may dominate the copepod biomass and occupy a pivotal position in fisheries food webs. Despite the ecological importance of this species, its taxonomic status and biogeographic range are not certain. An international collaborative project, the Calanoides carinatus ZooGene Project (CCZP), was designed during the 3rd International Zooplankton Production Symposium (Gijón, Spain) to examine population genetic variation of C. carinatus across its biogeographic range in the Atlantic Ocean. Samples were collected from populations of the western (off Brazil and Argentina) and eastern South Atlantic Ocean (off South Africa) as well as the eastern North Atlantic Ocean (off Spain). Ten individuals were sequenced from each region for a ~700 base-pair region of the mitochondrial cytochrome oxidase I (mtCOI) gene. Molecular phylogeographic analysis indicated that C. carinatus of the western S. Atlantic were genetically cohesive. Since the type locality of the species is near the Brazilian collections, we conclude that these populations are indeed C. carinatus, sensu stricto. Opposite, specimens from the eastern Atlantic differed from the western Atlantic samples by 21% for mtCOI sequence. The eastern Atlantic form was genetically similar (~2% mtCOI sequence differences) from Spain to Africa. These results are consistent with the designation of two different species from the western and eastern boundaries of the Atlantic Ocean. The geographical distribution of C. carinatus should thus be considered to include only the western boundary of the South Atlantic Ocean.
Wiebe, P. H., A. Bucklin, L. P. Madin, M. V. Angel, T. Sutton, F. Pages and R. R. Hopcroft.
Integrated at-sea morphological and molecular assessment of zooplankton biodiversity in the northwestern Atlantic Ocean from the surface to 5000 m (abstract).
Zooplankton from northwestern Atlantic tropical/subtropical waters were sampled at five stations from the surface to 5000 m. Environmental data and zooplankton samples were collected with a 102 m opening/closing MOCNESS trawl with 335 µm mesh nets from 5000 to 1000 m. Two smaller MOCNESS sampled the upper 1000 m. Ring net and water bottle casts, and blue-water SCUBA diving were also conducted. A team of taxonomic experts using traditional morphological approaches analysed samples at sea and provided identified specimens for determination of DNA barcodes for species recognition. Over 500 species were identified; >1000 specimens were placed in a queue for barcoding; 87 species were barcoded at sea. For several taxonomic groups, a significant fraction of the region’s known species were collected and identified (i.e. 65 ostracod species were identified of the 140 known species for the Atlantic Ocean were collected, plus at least six undescribed species, and the first DNA barcode for a planktonic ostracod was obtained). Also identified were >40 molluscs, >100 species of cnidarians, several hundred species of copepods, and >100 species of fish. At least 12-15 new species will be described from this effort. The deployment of specially-designed trawls to sample large volumes for small zooplankton is essential to provide an accurate assessment of species diversity at great depths. This study yielded preliminary confirmation of high species diversity and low species abundances in the deep sea. Below 1000 m, even rare species may have huge population sizes and play a critical role in the dynamics of deep-sea environments.(Poster)