Dataset: zoop_RHB0603
Deployment: RHB0603

"Samples collected with the MOCNESS's were processed using a standard protocol. On Deck: With completion of the tow, the nets were immediately washed with seawater as they were pulled on deck and the plankton still in the nets carefully moved into the cod-end. The cod-ends were placed in buckets with ice packs to cool the samples and moved expeditiously into the walk-in cold room to await analysis. Specimen removal: One by one the cod-ends were taken into the wet lab for digital photographing, and the picking and removal of large individuals of 1) gelatinous forms, 2) fish, and 3) macrozooplankton/nekton. Pickers described what was being removed and a recorder logged the information. The specimens removed were placed in numbered jars, shell vials, or dishes and the recorder wrote down all specimen information on the data sheets provided, linking the container number to specimen and collection data. This was done so that the actual taxonomic composition and species count for each sample can be reconstructed. The removed specimens were subject to a variety of procedures including further identification, dissection, preservation (in alcohol, frozen nitrogen, or formalin as appropriate), or taken for photographic imaging prior to preservation. Sample splitting and preservation: Within a few minutes of arrival, the stratified samples (with most large gelatinous forms, fish, and macrozooplankton/nekton removed) were passed to the individuals responsible for splitting the samples Generally ½ (split A) was preserved in formalin for future studies, including biomass estimates (e.g., displacement volume), species counts, and other quantitative analyses. The other half was split again with ¼ (split B) for live picking in the main lab and subsequent preservaton in alcohol for later taxonomic analysis. The other ¼ (split C) was immediately preserved in alcohol. After picking, the integrated sample (net 0) was generally split into two halves with one preserved in alcohol and the other in formalin." (from RV Ronald H. Brown Cruise 06-03 Report)

Cornils, copepods: A total of 63 species of calanoid copepods, primarily Aetideidae and Heterorhabdidae were identified. Only females and males were identified. Because of the ship movements we were unable to dissect individuals smaller than 2 mm, hence, they are probably under-represented in the species list. A lot of them will only be representatively caught in the 1/4-m MOCNESS. Some individuals of the identified species were taken to be "barcoded".

Bercial, copepods: A total of 15 species of calanoid copepods, belonging to 8 families were identified. These are species that were not included in the Cornils and Matsuura and Kuriyama studies.

Matsuura and Kuriyama, copepods: We aimed to obtain samples of these copepods, especially bathypelagic species, to compare the community structure between the Atlantic and Pacific, to see differences in the genetics of morphologically similar species, and obtain knowledge pertaining to the phylogeny of each family. During this cruise, we sorted out 534 Euaugaptilus and 464 scolecitrichids, and identified 25 and 22 species, respectively (Table 6). Among those, 24 Euaugaptilus and 17 scolecitrichid species were picked out for sequencing. After the cruise, we are going to identify the rest of the individuals, sequence COI and the 12S of these species, and discuss the differences between the Atlantic and Pacific, and the phylogeny of these species.

Hansen, decapods. Decapods collected during RHB0603 in the Sargasso Sea Samples were analyzed from the 10-m and 1-m MOCNESS (MOC-10 and MOC-1). A total of 18 tows were analyzed for the presence of Decapod shrimp: 11 samples from the MOC-1 and 7 samples from the MOC-10 (Table 2). Table 2. Tows with MOC-1 and MOC-10 that sampled Decapod shrimp at the five stations. MOC-1 MOC-10 Tow # Tow # Station 1 1, 2 1 Station 2 3, 4 2 Station 3 5, 7, 8 3 Station 4 9,10 4, 5 Station 5 11, 12 6, 7 A total of 366 individuals were sampled and analyzed from MOC-1 and MOC-10.

Copley, euphausiids: Euphausiids were identified from the live portions of several tows. Thysanopoda obtusifrons, a fairly large species (15-20 mm), was commonly found in the samples. Only about 47 individuals from 13 species were identified due to the small amount of time devoted to this activity. There was a shortage of microscopes and the euphausiids can be examined on land post-cruise whereas the gelatinous zooplankton needed to be identified immediately, while still alive. Nineteen identified specimens from eleven species were submitted for barcoding. For station 4, tow 10, net 3 and station 5, tow 11 nets 3, 4 and 5, and all nets from station 5, tow 13, the euphausiids were identified and measured in the lab from the formalin preserved split in March 2011 for a related project (WHOI-OLI).  Some shrinkage may have occurred.  Abundances (#/m^3) for these later samples are reported under the 'counts' column for these tows.

Watanabe, foraminifera: Skeletonized microzooplanktonic taxa were isolated and identified to species. Pictures were taken of specimens, and material were preserved for further morphological and genetic analyses. Effort was on the planktonic foraminifera, but significant data was collected on the radiolarians and phytoplanktonic coccolithophores as well.

Hopcroft, larvacea: Two principle purposes were addressed during the cruise: general photography of zooplankton, and identification of larvacean species for the barcoding (sequencing) effort. Approximately 1500 useful images have been taken of ~100 different living species of zooplankton at 4 MPix resolution. Depending on the species, from one to 20 pictures have been taken per specimen. In regard to the larvaceans, progress during the cruise was disappointing. Only 12 or 13 of the ~70 species described in this group were encountered during this cruise. With the possible exception of the smallest MOCNESS, these collecting systems extruded most of the larvaceans, and rendered those remaining unidentifiable in the collections. The Reeve net was generally successful, but densities of animals were unusually low. Even for the Reeve net, there appeared to be a relatively limited time-window over which material in the collection remained in a useful condition, and this may have contributed to an underestimation of species present. Only the most common tropical species were encountered, with the notable exception of the giant "mesopelagic" species, Bathochordaeus stygius. There appear to have been several distinct faunal shifts between stations. In the future, some method of slowing the degradation rate of the samples must be found for this specific group; perhaps partial "preservation" with ethanol while sorting the samples will work better.

Devi, larval fish: The fish larvae were picked live from the whole sample and were kept in the cold room for further analysis. The subsampled zooplankton preserved in ethanol and formaldehyde were also examined and the larvae picked out. The fish larvae were identified into different taxa. ! 43 species belonging to 18 families were present in the live samples analyzed. ! The rest of the samples were preserved in formaldehyde for further studies after the cruise. ! Maximum abundance and diversity(4 families and 7 species) were observed at lat 29o 57'N and lon 71o 01'W (MOC1 Tow 3 Net 5). ! Abundance and diversity decreased from there. Only 2 families with 7 species were found at 25o 00'N and 59o 56'W (taken from 0-1000m). ! At lat 33o 38'N and lon 69o 47'W, 5 species were encountered in 4 families (MOC10 Tow 1 Net 4). ! In all the three locations, the mesopelagic groups Myctophidae and Gonostomatidae were dominant. ! Two of the Cyclothone species (C. braueri and C. pallida) contributed the most to the numerical abundance. ! Maximum species diversity was observed in the family Myctophidae (15 species). ! Notoscopelus resplendens and Benthosema glaciale were the dominant species found in the area. ! Thunnus sp. was found only in one sample (MOC10 Tow5 Net 4) at 19o 49'N and 54o 44'W. ! The members of the Percoids were rare. ! 15 species were given for barcoding.

Panampunnayil, mysids: Five stations were sampled between 33 and 14 degrees N and 70 and 54 degrees W. At each station samples were collected using 1/4-m MOCNESS (upper 500m), 1-m MOCNESS (9 nets, upper 1000m) and 10-m MOCNESS (5 nets, down to 5000m), both day and night. Each sample was split. 50% was preserved in 5% formalin for silhouette analysis and later taxonomic analysis; 50% was preserved in alcohol for taxonomic analysis on board and removal of identified species for barcoding. Mysids were picked out of the samples preserved in alcohol and identified.

Madin, thaliacea: Thaliacea collected during RHB0603 in the Sargasso Sea Collections of Thaliacea (salps, doliolids, pyrosomes) were rather sparse on this track, although 17 species were obtained either in the net tows, or more often, from the dives. Net collected samples included: 1. Cyclosalpa polae (aggregate) 2. Thalia democratica (solo & aggregate) 3. Salpa cylindrica (solo) 4. Iasis zonaria (solo & aggregate) 5. Salpa aspera (aggregate) 6. Salpa fusiformis (solo & aggregate) 7. Helicosalpa virgula (solo) 8. Dolioletta gegenbauri 9. Doliopsis sp. 10. Doliolina sp. 11. Doliolum denticulatum 12. Pyrosoma atlanticum 13. Pyrosomella sp. Most of these were in the shallower nets, and were only found in small numbers (1 to 4 of each). Species collected during dives included: Brooksia rostrata (aggregate) Iasis zonaria (aggregate) Salpa aspera (solo & aggregate) Salpa fusiformis (solo & aggregate) Salpa maxima (solo & aggregate) Salpa cylindrical (solo) Pegea bicaudata (aggregate) Pegea confoederata (aggregate) Dolioletta gegenbauri Doliolina sp. Pyrosoma atlanticum All salps were identified and measured, and good specimens (mainly from dives) examined and photographed for anatomical details. These descriptions will become part of the detailed morphological information which will accompany the genetic data. A parallel project to develop a morphological and molecular phylogeny of the Thaliacea will be carried out by Madin and Bucklin over the next two years.

Pagès and Lindsay, other zooplankton: Copepods, Ctenophores, Amphipods and Cephalopods collected during RHB0603 in Sargasso Sea. Ctenophore forms that were identified from net samples included several cydippids belonging to the Haeckeliidae (Aulacoctena acuminata), the Bathyctenidae (Bathyctena chuni), the Pleurobrachiidae (Hormiphora palmata, Pleurobrachia sp.1), the Mertensiidae (Charistephane fugiens), and others. Lobates such as Kiyohimea usagi and Ocyropsis maculata maculata, the Cestoid Cestum veneris, and several Beroe species were also caught in net tows. Blue water diving allowed the collection of several individuals of the lobate Eurhamphaena vexilligera and the Thalassocalycid Thalassocalyce inconstans, in addition to some of the forms listed above. Twelve species of amphipods were sorted from the live samples, most of them large Physocephalata that were easy to spot. Many more species will undoubtedly be found upon examination of the formalin and ethanol-preserved samples. More than half of the gelatinous organisms captured during the blue-water SCUBA dives were host to hyperiid amphipods at varying stages of development. In many cases it was impossible to identify the hyperiid embryos to species or indeed genus level due to their early developmental stages. Individuals were extracted from the canals or gelatinous matrix of their hosts and placed in ethanol for sequencing. This should allow determination of any species specificity in host/parasite relationships as a factor contributing to species diversity maintenance mechanisms in the pelagic zone. The paucity of species belonging to the Physosomata at meso- and bathypelagic depths may have been a consequence of the dominance of these ecosystems by small siphonophores rather than the larger cnidarians that usually host these animals. Submersible dives should be conducted in this area to directly assess the types and numbers of large ctenophore and cnidarian forms to compare with the data gained on amphipods by net systems such as the MOCNESS. Thirteen species of cephalopods were identified in the MOCNESS samples. Of these, three were octopods (Cirrothauma murrayi, Bolitaena pygmaea, Tremoctopus violaceus), one was a vampyromorph (Vampyroteuthis infernalis), and the remaining nine were various squids belonging to at least five major groups (Bathyteuthids, Chiroteuthids, Cranchids, Histioteuthids, and Enoploteuthids). Many larval individuals were also sampled and these were recorded photographically, dissected to obtain tissue for DNA analysis, and preserved in formalin for subsequent taxonomic analysis. Sampling with larger trawls will be necessary to assess the true diversity of the cephalopod fauna at these sites, but the 335 micron mesh yielded specimens in immaculate condition, greatly simplifying taxonomic analyses.