October 2013 Archives

Over-wintering (or -summering)

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Autumn is a nostalgic time. The days grow shorter and the nights grow longer. The narrow angle of the sun casts long shadows, and the dry frigid air sucks the moisture from my breath. It's this time of year when the copepod in me starts to think about packing on fat stores, reducing my metabolic rate, and descending into dormancy for the long winter.

Myself, I've never actually diapaused. But lots of copepods do it--not just in the winter, but in some parts of the ocean, when conditions are unfavorable, some species diapause at other times of year. One thing that I do, however, is fill the dark autumn hours mining databases to answer questions about copepods. For example, check out this map:

Diapause04.jpg
(click to enlarge)

Can you guess what it is? You might need to squint. It's a little map I put together showing all of the places (according to the OBIS database) where oceanographers have recorded a species that undergoes diapause. You can see right off the strong bias toward where people have done more sampling (the North Atlantic). You can also see that most of the action is near the poles--but there are a few other interesting spots, such as upwelling regions around Africa and the Arabian Sea, as well as the Black Sea. 

The map isn't quite complete, but all this talk of diapause has made me sleepy.

Nick Record, signing off


Coral Reef Adventures

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No, the EMLab is not heading to Bermuda (at least not yet).  Instead, the post is to clue our reader(s) in on the continuing adventures of rogue SMS professor, Bob Steneck.

Bob has been studying coral reefs for a long time, and he is also an avid sailor.  He is also one of the most creative scientists I've met.  The latest evidence of his creativity: he has managed to combine sailing and coral reef ecology into an awesome sabbatical (assuming he survives).  

He has sailed his boat Alaria, a 34' cutter-rigged Pacific Seacraft, from Maine to Bermuda.  He will soon be on his way to the Antilles, where he will spend several months studying the reefs there.  You can keep tabs on his adventures through his blog.

RARGOM confirms 2012 was weird

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RARGOM, the Regional Association for Research on the Gulf Of Maine, selected the 2012 ocean heatwave as its topic for this year's annual science meeting.  Due to my obsession with 2012 and inability to duck responsibility, I ended up organizing the meeting.  

The meeting was held on Tuesday in Portsmouth (NH, not England--maybe next year), and we had a huge turnout. I think this speaks to the impact that the 2012 event had on the collective psyche of the Gulf of Maine community.  We had a great series of talks and posters (here's the agenda  and hopefully, we'll get the talks up on the RARGOM website soon), and I think we're starting to get a picture of just how weird things have gotten in the Gulf of Maine. Here are a few themes that stuck out for me:

  • Causes of 2012: According to Ke Chen (WHOI), the 2012 heatwave was caused by the atmosphere and likely related to a strongly positive NAO.  Although 2012 stands out over the long-term history, according to our own Hillary Scannell (UMaine/GMRI), the current climate should produce 2012-like events about once every 10 years.
  • Impact on Calanus: Yes, our old friend Calanus made several appearances at the meeting, but mostly in the context of 2013.  Desiree Tommasi (GFDL), filling in for NOAA's Kevin Friedland who is being held hostage by the government shutdown, reported that they were not able to define a spring phytoplankton bloom for 2013 and that the total abundance of zooplankton caught by NOAA this spring was very, very low.  Jeff Runge's (UMaine/GMRI) found an opposite pattern in the western Gulf of Maine: Calanus was very abundant, but perhaps occurred later in the year.  Heather Koopman (UNCW) said that they had incredibly low Calanus abundances in the Bay of Fundy this year, and that right whales were scarce.Razorbill_iceland.jpg
  • Bad year for birds: The saddest stories from 2012 were about seabirds, especially puffins and razorbills.  Tony Diamond (UNB) and Thomas Robben described a dramatic shift in the distribution of razorbills during the winter of 2012/2013.  Razorbills were found regularly in Florida during the winter and there were many reports of dead razorbills up and down the coast (next time, I'll put Tony and his necropsy photos after lunch).  Tony's hypothesis is that the temperature caused a shift in the distribution of their prey (likely herring).  Puffins were also hit hard, and according to Steve Kress (Audubon/Cornell), the culprit was not a lack of prey, but the wrong kind of prey.  Although they sound tasty, butterfish are terrible food for baby puffins.  The fish are too wide for the babies to swallow (shown in this video), and islands where the adults were finding lots of butterfish had very poor chick survival.  
  • Not just the Gulf of Maine: Catherine Johnson (DFO, BIO) gave a great overview of the impact of the 2012 event on the Canadian shelf.  She describes many of the same impacts, including observations of butterfish and a subtropical fish called a blue runner in Newfoundland.
  • Lobsters and fish: Suzy Arnold from the Island Institute had a poster describing the synthesis from their workshop this summer.  Jenny Sun (GMRI) presented an analysis of the connections between the US and Canadian lobster markets. Kathy Mills (UMaine/GMRI) gave an overview of our 2012 lobster story, including our idea about seasonal predictions.  She is starting to weave this story into a broader vision of how to think about climate adaptation in fisheries.  Building on this view, Jonathan Labaree (GMRI) described how 2012 has made climate impacts a major concern among fishermen.

Acoustic zooplankton time series from the NERACOOS buoys

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Warning: this entry contains TMA (too many acronyms). 

The Gulf of Maine Ocean Observing System (GoMOOS), part of the Northeast Regional Association of Coastal Ocean Observing Systems (NERACOOS), part of the Integrated Ocean Observing System (IOOS), has used buoys to continuously measure ocean physics for the past ~10 years. The longer this time series goes on, the more insights we can gain about the changing climate in the Gulf of Maine.

While these ocean observing systems are a critical piece of our understanding of ocean processes, some have lamented the difficulty of obtaining similar continuous, extended time series for the biology. Today I'm writing about such a time series that seems to have been overlooked in the NERACOOS data set. As part of the physics measurements, the buoys use acoustic Doppler current profilers (ADCPs) to measure currents. A byproduct of this measurement is acoustic backscatter, which can be an indication of biomass through the water column. Ideally, one would calibrate an acoustic instrument to target a particular group of organisms, but even uncalibrated acoustic backscatter can provide reasonable estimates of biomass, as well as grouping by behavioral type.

Below I've pasted three figures from a poster I presented yesterday at the Regional Association for Research in the Gulf of Maine (RARGOM) annual meeting. (You can click for larger versions.) Each figure shows the ADCP backscatter data at a different time scale, ranging from daily to inter-annual. You can easily see patterns of diel vertical migration (DVM, Fig. 1), seasonal bloom dynamics (Fig. 2), and changes at the inter-annual scale (Fig. 3). The DVM pattern persists throughout the entire time series, and the bloom dynamics are consistent through much of the gulf.

The final plot at the bottom (Fig. 4) shows the sort of time series one could obtain by converting this information into an estimate of zooplankton biomass. While not a perfect measurement of zooplankton, the time resolution and temporal/spatial extent of this information could fill in some gaps in our understanding of the Gulf of Maine system. As a bonus, it's information that we're already collecting and have been for the past ten years. 

Nick Record, signing off

Fig.1
AcousticZoo1.jpg
Fig.2
AcousticZoo2.jpg
Fig.3
AcousticZoo3.jpg
Fig.4
E_timeseries_surface.jpg


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