Follow along as NG Grantee Rhian Waller explores the surprisingly diverse corals that dwell deep in the fjords of Alaska, and discover what they can tell us about the rest of the ocean as well.
Tomorrow we sail out into Stephens Passage heading towards the fjords of Southeastern Alaska, to a sample site around six hours south of the Alaskan capitol Juneau, to a place called Tracy Arm, the northerly fjord branch of Holkham bay. Tracy Arm is possibly one of the most spectacular places I have ever been to. High snow topped mountains, steep sided walls dropping straight into aquamarine colored waters to thousands of feet below the surface, and terminated by twin glaciers – the North and South Sawyer. The scenery alone is enough to take your breath away, but what really holds it for me is the scenery below the frigid waters.
Corals. Large corals, growing to 8ft tall sticking right out of those up-and-down walls. Primnoa pacifica to be exact, the Red Tree coral, a gorgonian sea fan, very similar to those in tropical waters.
These are corals that are found in abundance in the deep-waters of the Gulf of Alaska – ~500m depth are where they are usually found. However, similar to the fjords of Chile (see Patagonian Fjords Expedition Posts here), this is an area where Deepwater Emergence occurs. Fjords often mimic environmental conditions seen in the deep ocean (cold all year, dark, little competition for space, etc.), so some deep species have been found shallow enough to SCUBA dive around, and even study.
In September 2010, myself and NOAA collaborators and colleagues set up a monitoring site for Red Tree corals in Tracy Arm fjord. These corals form vital habitat for many fisheries species here in Alaska (a dozen species of Rockfish and crab amongst others), so we want (and need!) to understand how this species survives both in the fjords and in the deep ocean so we can begin to protect it from fisheries damage. This project has involved tagging 38 large coral colonies on the walls of Tracy Arm, and taking small pieces every three months from each coral. These samples have been processed in my laboratory at the University of Maine to help us better understand how this species reproduces and makes larvae – processes vital for species survival, and if interrupted can be devastating for populations.
This is our final expedition of the project in Tracy Arm, so I have both the nervous excitement that going into the field always brings, but is also twinged with a little sadness at the finality. I’m excited to get the last piece of the puzzle, the final sample in our cycle and to see the corals again in the visibility that only winter in Alaska brings. With the glacier frozen up tight, the fjord clears from visibility of a just few feet (or less!) in summer, to 100+ft in winter. ‘Truly spectacular’ doesn’t begin to summarize it.
So the last two days have been taken over by travel, equipment testing and packing, and tomorrow we set out, into Stephens Passage and south to the fjords. Wish us luck on our expedition and stay tuned for more updates!