Voracious planktonic hydroids: unexpected predatory impact on a coastal marine ecosystem

Hydroids are typically attached, benthic cnidarians that feed on a variety of small prey. During sampling on Georges Bank in spring 1994, we found huge numbers of hydroids suspended in the plankton. They fed on young stages of copepods that are an important prey for fish, as well as on young fish themselves. Two independent methods were used to estimate feeding rates of the hydroids; both indicate that the hydroids are capable of consuming from 50% to over 100% of the daily production of young copepods. These results suggest that hydroids can have a profound effect on the population dynamics of zooplankton and young fish on Georges Bank

Effects of warm water intrusions on populations of macrozooplankton on Georges Bank, Northwest Atlantic

Author Posting. © The Authors, 2004. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Continental Shelf Research 25 (2005): 143-156, doi:10.1016/j.csr.2004.07.028.As part of the Georges Bank/North West Atlantic GLOBEC (Global Ocean Ecosystems Dynamics) Program, macrozooplankton and micronekton were collected on 30 Broad Scale Survey Cruises between January – June, 1995 –1999, using a 10 m2 MOCNESS (3mm mesh). The objective of this study is to examine the effects of warm water intrusions on populations of macrozooplankton, namely Salpa spp., Phronima spp., Neomysis americana, and Crangon septemspinosa, on Georges Bank. Salpa spp. and Phronima spp. showed a large degree of horizontal co-occurrence, being found predominantly in Upper Slope/Gulf Stream Water and Georges Bank/Gulf of Maine Water. Abundances of these taxa showed striking interannual variability, and were only abundant on the southern flank and in the Northeast Channel in late spring/early summer of 1995 and 1999, periods during which AVHRR imagery and hydrographic data showed the presence of warm water intrusions. These intrusions seemed to have little effect on the distribution of other macrozooplankton (e.g., Neomysis americana and Crangon septemspinosa). Warm water intrusions can directly affect Salpa spp. and Phronima spp. populations by advecting them onto Georges Bank, although other, more resident populations, especially those inside the 100m isobath, seem to be little affected by such intrusions.Additional thanks goes to Tom Niesen and Stan Williams for their advice on data analysis and interpretation. This work was supported by NSF award No. OCE96-17209 and NOAA award No. NA66GP0356 to S. M. Bollens provided from the US GLOBEC Northwest Atlantic/Georges Bank Program, a joint program of the National Science Foundation and the National Oceanic and Atmospheric Administration

Effects of turbulence on the feeding rate of a pelagic predator : the planktonic hydroid Clytia gracilis

Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Experimental Marine Biology and Ecology 333 (2006): 159-165, doi:10.1016/j.jembe.2005.12.006.Relatively little is known about the role of turbulence in a predator - prey system where the predator is a passive, pelagic forager. The Campanulariid hydroid Clytia gracilis (Cnidaria, Hydrozoa) is unusual because it occurs as planktonic colonies and is reported to forage passively in the water column on Georges Bank, Massachusetts, USA. In this study we investigated the role of various turbulence conditions on the feeding rate of C. gracilis colonies in laboratory experiments. We found a positive relationship between turbulence velocities and feeding rates up to a turbulent energy dissipation rate of ca 1 cm2 s-3. Beyond this threshold feeding rate decreased slightly, indicating a dome-shaped relationship. Additionally, a negative relationship was found between feeding efficiency and hydroid colony size under lower turbulent velocities, but this trend was not significant under higher turbulence regimes.P. Adamík received support from the WHOI Academic Programs Office via the 2002 Summer Student Fellowship and while writing this paper from the Ministry of Education of the Czech Republic (MSM 6198959212 and MSM 153100012)

Zooplankton length data from the 10m2 MOCNESS from R/V Endeavor, R/V Albatross IV,and R/V Oceanusbroadscale cruises in the Gulf of Maine and Georges Bank from 1995-1999 (GB project)

Dataset: MOC10data_lengthsZooplankton length data from the 10m2 MOCNESS from R/V Endeavor, R/V Albatross IV,and R/V Oceanusbroadscale cruises in the Gulf of Maine and Georges Bank from 1995-1999 For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/2327National Science Foundation (NSF) unknown GB NSF, National Oceanic and Atmospheric Administration (NOAA) unknown GB NOA

Key developmental transitions in human germinal center B cells are revealed by differential CD45RB expression

We previously reported that RO+ expression correlated with increased mutation, activation, and selection among human germinal center (GC) B cells. Here, we subdivided human tonsillar B cells, including IgD−CD38+ GC B cells, into different fractions based on RB expression. Although each subset contained RB+ cells, when used as an intrasubset marker, differential RB expression effectively discriminated between phenotypically distinct cells. For example, RB+ GC B cells were enriched for activated cells with lower AID expression. RB inversely correlated with mutation frequency, demonstrating a key difference between RB- and RO-expressing GC B cells. Reduced RB expression during the transition from pre-GC (IgM+IgD+CD38+CD27−) to GCB cells was followed by a dramatic increase during the GC-to-plasmablast (IgD−CD38++CD27+) and memory (IgD−CD38−CD27+) transition. Interestingly, RB+ GC B cells showed increased signs of terminal differentiation toward CD27+ post-GC early plasmablast (increased CD38 and RO) or early memory (decreased CD38 and RO) B cells. We propose that as in T cells, differential RB expression directly correlates with development- and function-based transitions in tonsillar B cells. Application of this RB:RO system should advance our understanding of normal B-cell development and facilitate the isolation of more discrete B-cell populations with potentially different propensities in disease pathogenesis

Event logs from the U.S. GLOBEC Georges Bank project, from 10 vessels and 104 cruises in the Gulf of Maine and Georges Bank area from 1994-1999 (GB project)

Dataset: eventlogsEvent logs from the U.S. GLOBEC Georges Bank project, from 10 vessels and 104 cruises in the Gulf of Maine and Georges Bank area from 1994-1999. Event logs provide an overall summary of the sampling activities during a cruise. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/2321National Science Foundation (NSF) unknown GB NSF, National Oceanic and Atmospheric Administration (NOAA) unknown GB NOA