Recruitment, growth and mortality of an Antarctic hexactinellid sponge, Anoxycalyx joubini.

Polar ecosystems are sensitive to climate forcing, and we often lack baselines to evaluate changes. Here we report a nearly 50-year study in which a sudden shift in the population dynamics of an ecologically important, structure-forming hexactinellid sponge, Anoxycalyx joubini was observed. This is the largest Antarctic sponge, with individuals growing over two meters tall. In order to investigate life history characteristics of Antarctic marine invertebrates, artificial substrata were deployed at a number of sites in the southern portion of the Ross Sea between 1967 and 1975. Over a 22-year period, no growth or settlement was recorded for A. joubini on these substrata; however, in 2004 and 2010, A. joubini was observed to have settled and grown to large sizes on some but not all artificial substrata. This single settlement and growth event correlates with a region-wide shift in phytoplankton productivity driven by the calving of a massive iceberg. We also report almost complete mortality of large sponges followed over 40 years. Given our warming global climate, similar system-wide changes are expected in the future

Improving Library Resource Discovery: Exploring the Possibilities of VuFind and Web Scale Discovery in a Consortial Environment

In late 2010, the Bridge Consortium (Carleton College and St. Olaf College) formed a task force to investigate web scale discovery. The goal? Recommend a product (like Summon or Primo Central) in time for the start of Fall 2011 classes. During this two-part session, members of the Bridge will take you inside what we did instead, why, how it’s going, and what we plan to do next. Part 1: Improving Discovery...It’s More Than a Single Product To improve access to and discovery of Bridge resources, we recommended (1) implementing an open source (VuFind) catalog overlay, with setup and ongoing support provided by Minnesota’s PALS consortium and also (2) redesigning web access to disparate library resources. We also recommended (3) continuing the search for the right web scale discovery tool. This first hour will discuss how we revised our charge, our criteria, why and how open source, and more about our selection process. Part 2: All About VuFind In the second hour, we will talk about how implemented VuFind as the Bridge catalog overlay for our current III system during the summer of 2011 and were live when students returned in September. We will cover the initial implementation process, our work to improve the interface based on user feedback, and potential future work as the consortium moves to new models of resource discovery. We will discuss the features of VuFind we found attractive, the pros and cons of working with an open source overlay, and our experience hosting VuFind at PALS, as well as our process for obtaining, analyzing, and applying users’ responses to the new overlay.To access the Part 1 presentation, please click on the DOWNLOAD button on the right

Recruitment, growth and mortality of an Antarctic hexactinellid sponge, Anoxycalyx joubini.

Polar ecosystems are sensitive to climate forcing, and we often lack baselines to evaluate changes. Here we report a nearly 50-year study in which a sudden shift in the population dynamics of an ecologically important, structure-forming hexactinellid sponge, Anoxycalyx joubini was observed. This is the largest Antarctic sponge, with individuals growing over two meters tall. In order to investigate life history characteristics of Antarctic marine invertebrates, artificial substrata were deployed at a number of sites in the southern portion of the Ross Sea between 1967 and 1975. Over a 22-year period, no growth or settlement was recorded for A. joubini on these substrata; however, in 2004 and 2010, A. joubini was observed to have settled and grown to large sizes on some but not all artificial substrata. This single settlement and growth event correlates with a region-wide shift in phytoplankton productivity driven by the calving of a massive iceberg. We also report almost complete mortality of large sponges followed over 40 years. Given our warming global climate, similar system-wide changes are expected in the future

<i>Anoxycalyx joubini</i> growth on rack at New Harbor, Explorers Cove.

<p>One of the racks at Explorers Cove in (A) 1988, before <i>A. joubini</i> settlement; (B) 2004, with 4 <i>A. joubini</i>; and (C) 2010, some <i>A. joubini</i> falling off of structure, but still alive.</p

<i>Anoxycalyx joubini</i> on the gangplank at Hut Point, McMurdo Station.

<p>(A) 1989, after anchor ice had removed 100% cover of large <i>H. balfourensis </i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056939#pone.0056939-Dayton4" target="_blank">[15]</a>, (B) the same gangplank with <i>A. joubini</i> in 2010.</p

Large <i>Anoxycalyx joubini</i> at Cape Armitage, McMurdo Station.

<p>Two large <i>A. joubini</i> at a depth of 60 m, 1967. (A) The larger sponge on the right (<i>A. joubini</i>) is approximately 2 m tall. (B) <i>A. joubini</i> in photo is approximately 1.75 m tall.</p

The timing of the major iceberg events in the southern Ross Sea.

<p>The combined presence of the icebergs were strongest from mid-2002 to late 2003. Figure modified from Thrush and Cummings <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056939#pone.0056939-Thrush1" target="_blank">[22]</a>.</p