Seascape Projects

A closer look at Gulf of Maine warming

By Nick Record on February 28, 2014 9:00 PM | No Comments

On a frigid February Friday, when I should otherwise be in Hawaii at the Ocean Sciences meeting, there is one substitution for staying warm: looking at Gulf of Maine temperature trends. This blog is a closer look at the Gulf of Maine warming that Andy described in an earlier post (and a still earlier post). A closer look shows that the warming over the past 30 years (about .3 deg C per year) is not uniform across the gulf, or throughout the year. The plot shows the warming trend for each month across the gulf. The red regions in the upper left sub plot, for example, show areas where January temperatures have warmed over the past 30 years. The next sub-plot shows February and so on. Blue indicates a cooling trend. The twelve sub plots are for the twelve months. The Bay of Fundy is consistently warming, and the autumn is generally warmer now than in the 1980s. But there is some nuance here. February, for example, has been getting cooler. By contrast, here is the same plot looking at the past 10 years (same color scale): This represents a gulf-wide 2-3 degree warming over the past 10 years. This histogram summarizes the data, similar to Andy's last post. Although these plots show warming trends, they don't produce warming themselves, and my fingers are starting to freeze up. This may be the last thing I type today. Nick Record, signing off

A dynamical systems link between traits and ecosystems

By Nick Record on February 24, 2014 6:19 PM | No Comments

Over the past few decades, ocean ecosystem modelers like myself have gone from a Nutrient-Phytoplankton-Zooplankton picture of the ocean that looks like this: ...to one that looks more like this: The motivation, I would say, has been that the simple paradigm misses important processes, like species life history, or important properties, like diversity and its consequences. (Not to mention the myriad of Z that do not consume P.) The more complex picture, although impressive looking, comes with baggage. Among others, there is also the problem of parameterizing these models. Lots of boxes and arrows means lots of rates and properties to be measured--increasing roughly with the square of the number of species (or state variables). One approach to simplifying this mess is to organize the ocean according to certain traits. Trait-based perspectives are not new, and I think they might be able to clean up the NNNNPPPPPZZZZZZZZZZ spider web we're tinkering around with these days. For example, we can approximate the distribution of a trait across species with a curve. With some analysis, we can then look at the effect of the shape of this curve on the structure of the community. In the example below, a Gaussian distribution of growth rates (gamma) produces realistic rank-abundance curves in a zooplankton population. Different curves produce different community-level patterns. This is an idealized analytical model. The real world is messier. Still, as long as we are modeling species by using collections of ecologically important traits, we can use the distributions of those traits to inform the model. As a messier example, I'll draw from a more complex copepod model. We included a number of traits, such as activation energies, development times, and diapause strategies (many copepods go into dormancy during certain stages). These traits have been painstakingly tabulated across many species by people who I assume have lots of coffee and live in cold, cloudy places. By drawing from these distributions in a sort of stochastic way, and plugging the model into different parts of the ocean, we get very different communities emerging at different places. The next image shows preliminary output from a North Atlantic model. These are the results for the diapause trait. Basically, in northern latitudes, species that diapause make up the majority of the population. Closer to the equator, they don't fare well. On the right you can see an image of what the population looks like in terms of the size of the animals, and a distribution of the diapause trait as a function of life stage. In the north, there are large diapausing species with long development times. In the south, the opposite. If you know the North Atlantic well, you'll recognize that this map is not perfect, and we are still a ways from describing the whole ecosystem this way. Still, by shifting the perspective away from the individual species, and towards properties of the community, we are able to make some more sense out of the NNNNNNPPPPPPPZZZZZZZZZZZZ spider web. Nick Record, signing off Hubbell SP (2001) The unified neutral theory of biodiversity and biogeography (MPB-32) (Vol. 32). Princeton University Press. Record NR, Pershing AJ, Maps F (2013) Emergent copepod communities in an adaptive trait-structured model. Ecol Model Record NR, Pershing AJ, Maps F (2013) The paradox of "the paradox of the plankton". ICES J. Mar. Sci.

The Gulf of Maine is Warming Fast!

By Andy Pershing on January 28, 2014 10:25 AM | No Comments

I'm at the NCSE "Climate Solutions Conference" in Washington, DC this week. I was invited to talk about the lessons we can learn from the 2012 ocean heat wave in a session on "Managing Fisheries Under Climate Change." For my talk, I was curious whether the warming we've seen in the Gulf of Maine is unique. Short answers: it is very unique: since 2004, the Gulf of Maine has warmed faster than 99.85% of the global ocean.

To get to this number, I grabbed the global sea surface temperature (SST) data set from NOAA's optimally interpolated product. I removed the mean annual cycle (1982-2011) to produce daily anomalies. I then selected 2,000 point at random (shown over the mean SST from June):

At each point, I computed the linear trend over the last 10 years (January 2004-September 2013). At this relatively short time scale, I would expect to see a lot of variability--a lot of places warming, but also a lot of places cooling, and this is what I found. The mean trend is 0.006°C/yr and there are slightly more points that are warming (1024 points) than cooling (976).

The distribution of trends is pretty much normal (in the statistical sense):

but the Gulf of Maine is decidedly abnormal. The Gulf is warming at 0.23°C/yr (see my previous post), and from my 2000 randomly selected points, I found only four (FOUR!) that were warming faster (red stars on the map). Turns out one of them was from the Gulf of Maine (go figure), and that the other points were from the Kuroshio extension region northeast of Japan. This makes some sense oceanographically and is probably driven by a northward shift in the Kuroshio (the Pacific's Gulf Stream).

According to this analysis, the warming in the Gulf is remarkable, and frankly, a little scary. However, it is important to remember that this is just a statistical analysis. At some point, the trend will slow, but we don't know when and by how much. There is clearly more work to be done to understand the mechanisms that are driving the current trend. And, there is also an opportunity to use the Gulf of Maine to understand how an ecosystem responds to rapid climate change.

Are chaetognaths gelatinous? You be the judge

By Nick Record on January 22, 2014 6:26 PM | 1 Comment

(Apologies in advance for the perhaps obscure and esoteric content of this entry.)

The "Jelly Ocean Hypothesis" suggests that due to human-driven changes in the environment, we are headed toward an ocean dominated by jellyfish. Before determining whether this scientifically intriguing dystopian nightmare comes to pass, we need to agree on what classifies as a "gelatinous zooplankton".

Some people assert that chaetognaths fit into this category; others do not. Since we are debating this in the lab now, here is some information for context. What we need is a measure of how gelatinous something is. Ideally we would like to have a measure of carbon-to-volume ratio for each taxon--basically a measure of organic density--but for now, dry weight as a percentage of wet weight (DW as %WW) will have to do. --Basically the amount of the organism that is not water.

ctenophore copepod chaetognath

gelatinous not gelatinous ??

Here are the numbers:

Euphausiid DW as %WW: range 20-24% (depending on stage) +/- ~3

(Iguchi & Ikeda 1998 table 1)

Copepod DW as %WW: average ~19% +/- 10

(computed from Mauchline 1998 fig 50)

Chaetognath DW as % WW: 8%

(Sameoto 1972 reported in Feigenbaum 1982)

Thaliacea DW as %WW: average 5.5% +/- 2.47

Ctenophora DW as %WW: average 3.53% +/- 0.92

Cnidaria DW as % WW: average 4.07% +/- 1.23

(Lucas et al. 2011)

And in graphical format:

<--------- more gelatinous less gelatinous --------->

I think this crude and cursory analysis settles the debate. Now we can get back to talking about copepods.

Nick Record, signing off

References

Lucas CH, Pitt KA, Purcell JE, Lebrato M, Condon RH (2011) What's in a jellyfish? Proximate and elemental composition and biometric relationships for use in biogeochemical studies. Ecology 92:1704.

Feigenbaum D (1982) Feeding by the chaetognath, Sagitta elegans, at low temperatures in Vineyard Sound, Massachusetts. Limnol. Oceanogr. 27(4): 699-706.

Iguchi N, Ikeda T (1998) Elemental composition (C, H, N) of the euphausiid Euphausia pacifica in Toyama Bay, southern Japan Sea. Plankton Biol. Ecol. 45(1): 79-84.

Mauchline (1998) The biology of calanoid copepods

Sameoto DD (1972) Yearly respiration rate and estimated energy budget for Sagittu elegans. J. Fish. Res. Bd. Can. 29: 987-996.

Gulf of Maine Temperature Trends

By Andy Pershing on January 12, 2014 6:06 PM | No Comments

Happy 2014 to you, dear Seascape reader(s)! To kick off another year of oceanographic musings, here is the updated temperature trend for the Gulf of Maine:

This is essentially the same figure we used to show the 2012 event, but extended through early September (the last available AVHRR OI field). As you can see, 2013 was cooler than 2012, but was still a very warm year. The recent warming trend has continued (it's actually a little stronger), and 2012 still stands out as unusual. Of course, this doesn't include the impact of a few very cold days recently (I'm talking about you, polar vortex), nor does it include the very mild weather we're experiencing now. Temperatures in the ocean change much more slowly than those on land, and water temperatures are a better indicator of climate trends than the weather on a given day. I hope to update the SST animations in a couple of weeks.

Over-wintering (or -summering)

By Nick Record on October 30, 2013 3:34 AM | 2 Comments

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: (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

By Andy Pershing on October 27, 2013 1:52 PM | No Comments

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

By Andy Pershing on October 13, 2013 10:53 AM | No Comments

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.
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

By Nick Record on October 9, 2013 2:27 PM | No Comments

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

Fig.2

Fig.3

Fig.4

Poster for ICES Conference

By Andy Pershing on September 20, 2013 12:39 PM | No Comments

I'm starting my tour of the world's volcanic islands with a trip to Iceland. I'll be attending the ICES Annual Science Conference and presenting a poster on the "Impact of the 2012 Ocean Heat Wave on Fish and Fisheries." You can download the poster PershingICES_olf.pdf I hope to return with some pictures of glaciers.

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