Rubens M. Lopes

Omnivory in the calanoid copepod Temora longicornis: feeding, egg production and egg hatching rates

We measured in laboratory experiments the ingestion, egg production and egg hatching rates of female Temora longicornis as a function of diet. The diets consisted of a diatom (Thalassiosira weissflogii), an autotrophic dinoflagellate (Heterocapsa triquetra), and a bacterivorous ciliate (Uronema sp.) given as sole foods, or combinations of these single-food items: diatom+dinoflagellate, diatom+ciliate, dinoflagellate+ciliate, and diatom+ciliate+dinoflagellate. For the three single-item diets, the functional response was similar; i.e., ingestion rate increased linearly with food concentration (food range: ∼25 to ∼600 μg C l−1). When all diets were considered, maximum daily carbon ration (∼70% of body weight) was independent of food type. However, the maximum daily egg production rate (12% of body carbon) was obtained with the diatom diet. For all diets, both ingestion and egg production rates increased with food concentration. Ingestion and egg production rates were affected differently by the interaction of food concentration and food type: at low food concentrations, ingestion rates were highest on diets containing the diatom. At high food concentrations, egg production rates were highest on the two phytoplankter diets and their combination. The presence of the ciliate in the diet did not enhance ingestion rate or egg production. Mixed-food diets did not enhance egg production relative to single-food diets. Hence, dietary diversity did not appear to be particularly advantageous for reproduction. Carbon-specific egg production efficiency (EPE; egg production/ingestion) was independent of food concentration and type, and equaled 9%. Egg hatching success was low (mean<30%) and independent of food concentration and type, and egg production rates. Our results are consistent with previous observations that egg production in T. longicornis is enhanced during diatom blooms. However, the relatively low EPE and egg hatching success suggest that reproduction and recruitment in this study were severely constrained by the biochemical composition of the diet, or the physiological condition of the females towards the end of their season of growth in Long Island Sound.

High summer abundances of small pelagic copepods at the Antarctic Polar Front—implications for ecosystem dynamics

Within the framework of the SO-JGOFS, we investigated the distribution of small copepods ðo2: 0m mÞ in relation to the hydrography of the Antarctic Polar Front during summer 1995/96. The community of small copepods was dominated by Oithona similis, followed by Oithona frigida and Ctenocalanus citer. The total abundance of these copepods was extremely high throughout the study area, with peaks of up to 49; 000 ind: m � 3 ; to which naupliar and early copepodid stages (CI–CIII) contributed a high percentage. The accumulation of such a high standing-stock of small copepods is probably related to retention mechanisms provided by the meandering structure of the frontal system and to the biology of the dominant species Oithona similis, Oithona frigida, and Ctenocalanus citer. Stage distribution and metabolic demand of the dominant species indicate a very active and productive zooplankton community, with high grazing pressure on smaller plankton particles and faecal material, leading to high recycling efficiencies and low export rates due to sinking material. This study gives further support to recent findings that small copepod species and early developmental stages of all species are key components of the plankton food web of the Southern Ocean. r 2002 Elsevier Science Ltd. All rights reserved.

Marine Bioinvasions in the Brazilian Coast: Brief Report on History of Events, Vectors, Ecology, Impacts and Management of Non-indigenous Species

The Brazilian coast extends for about 8000 km from Cape Orange (4°N) to Chui (34°S) (Fig. 27.1). This long coastline comprises a variety of ecosystems under the influence of oligotrophic waters transported by two western boundary currents, the Brazil and North Brazil currents (Stramma and England 1999), together with continental influences related to a wide spectrum of river inputs, the largest of which being the massive Amazon River plume in the north and the combination of the La Plata and Patos Lagoon outflows in the south (Castro Filho and Miranda 1998). Seasonal or intermittent intrusions of cold and nutrient-rich oceanic waters carried underneath the Brazil and North Brazil currents (the so-called South Atlantic Central Water) is another important physical forcing on regional shelf ecosystems of Brazil, particularly on the Southern Brazilian Bight and more southern areas (Lopes et al. 2006). Regionally important coastal ecosystems are (1) sandy beaches, occurring from north to south, with the largest ones in southernmost areas of the state of Rio Grande do Sul; (2) mangrove forests, which occur from the northern tip of the country to the state of Santa Catarina in the south, (3) coral reefs, ranging from Maranhão to Bahia including the largest coral reef system of the South Atlantic, the Abrolhos Reefs (Leão et al. 2003); (4) rocky shores, spread along the entire coast from the northeast to the south, but more extensive in the southeast; (5) coastal lagoons, such as the Cananéia-Iguape estuarine complex in the state of São Paulo and the Patos Lagoon in the state of Rio Grande do Sul; (6) saltmarshes, of regional importance only south of the state of São Paulo; and (7) sandy to muddy bottoms of the infralitoral realm down to the shelf break (Seeliger and Kjerfve 2000). Given such a large array of marine ecosystems and the extent of the Brazilian coastline, the country is undoubtedly a major receptor and donor of tropical and subtropical organisms in the world’s oceans. Research on marine bioinvasions is a relatively new topic in Brazil. The first comprehensive lists of introduced and invasive species are starting to be compiled and the understanding of patterns of invasion strategies is far from being accom-

Marine zooplankton studies in Brazil: a brief evaluation and perspectives

Marine zooplankton research in Brazil has been primarily descriptive, with most studies focusing on community structure analysis and related issues. The composition and spatial distribution of several taxonomic groups are currently well known, although less-abundant and small-sized taxa as well as initial stages of almost all species have received little attention. Some numerically important taxa such as heterotrophic protists, ctenophores, acoel turbellarians and ostracods remain virtually unstudied. Large sectors of the continental shelf have not been sampled in detail, particularly those areas influenced by the North Brazil Current (5 degrees N-15 degrees S). Zooplankton abundance and biomass in offshore waters have seldom been quantified, and information on the distribution and vertical migration of meso- and bathypelagic species are lacking. Additional faunistic assessments must target those less-studied taxa and geographical locations. However, priority in ecological studies should be given to process-oriented investigations aimed at understanding the mechanisms controlling zooplankton distribution, trophic interactions within pelagic food webs and production cycles in relation to the physical environment. An effort should be made to incorporate state-of-the-art sampling technology and analytical methods into future research projects.

Free-Living and Plankton-Associated Vibrios: Assessment in Ballast Water, Harbor Areas, and Coastal Ecosystems in Brazil

Ballast water (BW) is a major transport vector of exotic aquatic species and pathogenic microorganisms. The wide-ranging spread of toxigenic Vibrio cholerae O1 from harbor areas has been frequently ascribed to discharge of contaminated BW into eutrophic coastal environments, such as during the onset of the seventh cholera pandemic in South America in the early 1990s. To determine the microbiological hazards of BWs transported to Brazilian ports, we evaluated water and plankton samples taken from (i) BW tanks of recently arrived ships, (ii) port areas along the Brazilian coastline from ∼1 to 32°S and (iii) three coastal areas in São Paulo State. Vibrio concentration and toxigenic V. cholerae O1 occurrence were analyzed. Plankton-associated vibrios were more abundant than free-living vibrios in all studied environments. V. cholerae was found in 9.5% of ballast tanks and 24.2% of port samples, both as free-living and attached forms and, apart from the Santos harbor, was absent off São Paulo State. Toxigenic V. cholerae O1 isolates (ctxA+, tcpA+), involved in cholera disease, were found in BW (2%) and harbor (2%) samples. These results confirm that BW is an important carrier of pathogenic organisms, and that monitoring of vibrios and other plankton-attached bacteria is of paramount importance in BW management programs.

An empirical assessment of the consistency of taxonomic identifications

Abstract Plankton counting and analysis is essential in ecological study, yet scant literature exists as to the reliability of those counts and the consistency of the experts who make the counts. To assess how variable expert taxonomic identifications are, a set of six archived mesozooplankton samples from a series of Longhurst Hardy Plankton Recorder net hauls were counted by expert zooplankton analysts located at six marine laboratories. Sample identifications were repeated on two separate days with over 700 target specimens counted and identified on each day across the samples. Twenty percent of the analysts returned counts that varied by more than 10%. Thirty-three percent of analysts exhibited low identification consistencies, returning Intraclass Correlation Coefficient scores of less than 0.80. Statistical analyses of these data suggest that over 83% of the observed categorical count variance can be attributed to inconsistencies within analysts. We suggest this is the root cause of variation in expert specimen labelling consistency.

Genome Sequence of the Bacterioplanktonic, Mixotrophic Vibrio campbellii Strain PEL22A, Isolated in the Abrolhos Bank

Vibrio campbellii PEL22A was isolated from open ocean water in the Abrolhos Bank. The genome of PEL22A consists of 6,788,038 bp (the GC content is 45%). The number of coding sequences (CDS) is 6,359, as determined according to the Rapid Annotation using Subsystem Technology (RAST) server. The number of ribosomal genes is 80, of which 68 are tRNAs and 12 are rRNAs. V. campbellii PEL22A contains genes related to virulence and fitness, including a complete proteorhodopsin cluster, complete type II and III secretion systems, incomplete type I, IV, and VI secretion systems, a hemolysin, and CTXΦ.

Current distribution of the exotic copepod Pseudodiaptomus trihamatus Wright, 1937 along the northeastern coast of Brazil

Instituto Oceanografico da Universidade de Sao Paulo Departamento de Oceanografia Biologica (Praca do Oceanografico 191, 05508-120 Sao Paulo, SP, Brasil) **rmlopes@usp.br The introduction of exotic species is a major cause of depletion and extinction of native populations, a threat only surpassed by habitat destruction (Williamson, 1999). Exotic organisms may inflict negative impact upon native species by several ways, including transmission of pathogens and parasites, genetic degradation, habitat utilization, direct predation or competition for food, and other food web interactions (Williamson, 1996). Aquaculture activities account for a large number of accidental introductions worldwide because of non-intentional releases of small-sized organisms associated with target imported species (Carlton, 1996; Weigle

Diversity and ecological structure of vibrios in benthic and pelagic habitats along a latitudinal gradient in the Southwest Atlantic Ocean

We analyzed the diversity and population structure of the 775 Vibrio isolates from different locations of the southwestern Atlantic Ocean (SAO), including St. Peter and St. Paul Archipelago (SPSPA), Abrolhos Bank (AB) and the St. Sebastian region (SS), between 2005 and 2010. In this study, 195 novel isolates, obtained from seawater and major benthic organisms (rhodoliths and corals), were compared with a collection of 580 isolates previously characterized (available at www.taxvibrio.lncc.br). The isolates were distributed in 8 major habitat spectra according to AdaptML analysis on the basis of pyrH phylogenetic reconstruction and ecological information, such as isolation source (i.e., corals: Madracis decactis, Mussismilia braziliensis, M. hispida, Phyllogorgia dilatata, Scolymia wellsi; zoanthids: Palythoa caribaeorum, P. variabilis and Zoanthus solanderi; fireworm: Hermodice carunculata; rhodolith; water and sediment) and sampling site regions (SPSPA, AB and SS). Ecologically distinct groups were discerned through AdaptML, which finds phylogenetic groups that are significantly different in their spectra of habitat preferences. Some habitat spectra suggested ecological specialization, with habitat spectra 2, 3, and 4 corresponding to specialization on SPSPA, AB, and SS, respectively. This match between habitat and location may reflect a minor exchange of Vibrio populations between geographically isolated benthic systems. Moreover, we found several widespread Vibrio species predominantly from water column, and different populations of a single Vibrio species from H. carunculata in ecologically distinct groups (H-1 and H-8 respectively). On the other hand, AdaptML detected phylogenetic groups that are found in both the benthos and in open water. The ecological grouping observed suggests dispersal and connectivity between the benthic and pelagic systems in AB. This study is a first attempt to characterize the biogeographic distribution of vibrios in both seawater and several benthic hosts in the SAO. The benthopelagic coupling observed here stands out the importance of vibrios in the global ocean health.

Comparison of zooplankton community structure between impacted and non-impacted areas of Paranaguá Bay Estuarine Complex, south Brazil

We analysed the seasonal distribution of the zooplankton community in an anthropogenically impacted area (Paranaguá Bay) and a non-impacted area (Laranjeiras Bay) of the Paranaguá Bay Estuarine Complex. Large phytoplankton (> 50 μm) and zooplankton were collected every two months, between August 2003 and June 2004. The phytoplankton community was numerically dominated by diatoms (78%) and dinoflagellates (19%). Zooplankton abundance varied between 670 and 100,716 individuals m–3, with a dominance of copepods, mainly the calanoids Acartia lilljeborgii, Acartia tonsa and Pseudodiaptomus acutus. A clear seasonal pattern was observed: copepods were significantly more abundant during the rainy than in the dry season. Significant differences in abundance between the two bays were detected only for cirripede larvae, which were more abundant in Paranaguá Bay. This lack of difference between the two areas was probably a consequence of the water circulation along the estuary, which may have diluted and dispersed the pollutants from Paranaguá Bay to other areas of the estuary.