<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<br>
<div class="moz-forward-container">
<p>Please join us Today, Mar 9 for our EOAS speaker at 3:30 in CAR 101:</p>
<span style="font-size:12.0pt;font-family:"Times New
Roman""></span> <br>
<b><font size="+3"><span style="font-size:12.0pt;font-family:"Times New
Roman"">Jeffrey W. Krause</span></font></b><br>
<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height:
normal">
<span style="font-size:12.0pt;font-family:"Times New
Roman"">Dauphin Island Sea Lab, Dauphin Island, AL 36528</span></p>
<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height:
normal">
<span style="font-size:12.0pt;font-family:"Times New
Roman"">Department</span><span style="font-size:12.0pt;mso-bidi-font-size:11.0pt;font-family:"Times
New Roman""> of Marine Sciences, University of South Alabama, Mobile, AL 36688</span></p>
<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height:
normal">
<span style="font-size:12.0pt;mso-bidi-font-size:11.0pt;font-family:
"Times New Roman""> </span></p>
<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height:
normal">
<br>
</p>
<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height:
normal">
<font size="+2"><b><span style="font-size:12.0pt;font-family:"Times New
Roman";color:#222222; background:white">The North Atlantic spring phytoplankton bloom: a new spin on an old story</span></b></font></p>
<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height:
normal">
<span style="font-size:12.0pt;font-family:"Times New
Roman""><br>
</span></p>
<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height:
normal">
<span style="font-size:12.0pt;mso-bidi-font-size:11.0pt;font-family:
"Times New Roman""></span></p>
<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height:
normal">
<span style="font-size:12.0pt;mso-bidi-font-size:11.0pt;font-family:
"Times New Roman""> </span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;mso-bidi-font-size:11.0pt;
line-height:107%;font-family:"Times New Roman"">Diatoms’ contribution to primary productivity and organic matter export are significant in the high-latitude North Atlantic
marine ecosystems.<span style="mso-spacerun:yes"> </span>Unlike other abundant phytoplankton groups, diatoms have an obligate silicon requirement; therefore, silicon availability has the potential to regulate major high-latitude events like the spring bloom.<span style="mso-spacerun:yes">
</span>Waters in the high-latitude sector of the Atlantic (e.g. coastal Greenland, Faroe Islands, Barents Sea, Svalbard) have lower pre-bloom silicic acid concentrations than nitrate.<span style="mso-spacerun:yes">
</span>Given diatoms require Si and N in near unity, the deplete Si relative to N sets a potential control on diatom productivity in this system, such that Si could limit diatom biomass yield in a bloom.<span style="mso-spacerun:yes">
</span>Recent publications have reported 20-year declines in silicic acid concentrations between ~60 – 75 °N latitude in the Atlantic.<span style="mso-spacerun:yes">
</span><span style="mso-spacerun:yes"> </span>Despite the clear changes in Si availability, there are no reported data for the magnitude of diatom Si uptake and whether ambient silicic acid limits silicon uptake by diatoms or their growth.<span style="mso-spacerun:yes">
</span>Here we report data from the West Greenlandic Nuup Kangerlua fjord during the development of the spring bloom over two months at a time-series site.<span style="mso-spacerun:yes">
</span>This site is influenced by the subpolar mode water, Greenland coastal water and early-season glacial melt water.
<span style="mso-spacerun:yes"> </span>The ambient silicic acid persistently limited the rate of Si uptake by diatoms and eventually limited their growth at the bloom peak.<span style="mso-spacerun:yes">
</span>Temporally concurrent with growth limitation by silicic acid availability, diatom settling velocity increased to pre-bloom levels, reflective of physiological stress, and an increase in the number of dead cells among the total diatom assemblage.<span style="mso-spacerun:yes">
</span>These data suggests that silicon availability plays an important role in terminating the spring bloom in this region when diatoms are favored to dominate the bloom sequence.<span style="mso-spacerun:yes">
</span></span></p>
<p><style>
<!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;
mso-font-charset:0;
mso-generic-font-family:auto;
mso-font-pitch:variable;
mso-font-signature:-536870145 1107305727 0 0 415 0;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;
mso-font-charset:0;
mso-generic-font-family:auto;
mso-font-pitch:variable;
mso-font-signature:-520092929 1073786111 9 0 415 0;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{mso-style-unhide:no;
mso-style-qformat:yes;
mso-style-parent:"";
margin-top:0in;
margin-right:0in;
margin-bottom:8.0pt;
margin-left:0in;
line-height:107%;
mso-pagination:widow-orphan;
font-size:11.0pt;
font-family:Calibri;
mso-ascii-font-family:Calibri;
mso-ascii-theme-font:minor-latin;
mso-fareast-font-family:Calibri;
mso-fareast-theme-font:minor-latin;
mso-hansi-font-family:Calibri;
mso-hansi-theme-font:minor-latin;
mso-bidi-font-family:"Times New Roman";
mso-bidi-theme-font:minor-bidi;}
.MsoChpDefault
{mso-style-type:export-only;
mso-default-props:yes;
font-size:11.0pt;
mso-ansi-font-size:11.0pt;
mso-bidi-font-size:11.0pt;
font-family:Calibri;
mso-ascii-font-family:Calibri;
mso-ascii-theme-font:minor-latin;
mso-fareast-font-family:Calibri;
mso-fareast-theme-font:minor-latin;
mso-hansi-font-family:Calibri;
mso-hansi-theme-font:minor-latin;
mso-bidi-font-family:"Times New Roman";
mso-bidi-theme-font:minor-bidi;}
.MsoPapDefault
{mso-style-type:export-only;
margin-bottom:8.0pt;
line-height:107%;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;
mso-header-margin:.5in;
mso-footer-margin:.5in;
mso-paper-source:0;}
div.WordSection1
{page:WordSection1;}
-->
</style></p>
</div>
</body>
</html>