Month: January 2018

[Research news] Are sand lance embryos particularly sensitive to high CO2?

This article has been cross-posted at news sites of Connecticut SeaGrant, Stellwagen Bank National Marine Sanctuary, and the Early Life History Section of the American Fisheries Society.


By Hannes Baumann

On this dimly lit November afternoon, rain mercilessly drenched scientists and crew on board the R/V Auk as it slowly navigated the waters of Stellwagen Bank. A world like a wet sponge. Sky and ocean, indistinguishable.

Thanksgiving, the next day.

Despite the circumstances, the team’s mood was nothing short of elated. Our small beam trawl had just spilled hundreds of silvery fish on deck, wriggling like eels. They were Northern sand lance (Ammodytes dubius).

Running ripe adults.

Spawning.

Apparently, they like Thanksgiving, too.

—————

As the ship docked back in the Scituate, Mass., harbor that day, the rain thinned to hazy darkness.

“Let’s get a coffee and then on the road,” mumbled Chris, who led the team, “the real work of the experiments has just begun.”

Chris RV Auk Sediment grab
Chris Murray, a member of the research team, checks the contents of a sediment grab for sand lance. Photo: Jacob Snyder / Red Skies Photography

RV-Auk
The RV Auk in early morning, getting ready for another sand lance sampling trip to Stellwagen Bank. Photo: Hannes Baumann
Stellwagen Bank, the National Marine Sanctuary just north of Cape Cod, is a true hotspot for some of the Atlantic Ocean’s most iconic creatures: whales, seals, tuna and seabirds, who all share a particular appetite for this one fish – sand lance. Some experts in the sanctuary’s ecosystem call this species its “backbone.” Others consider it a classic forage fish, responsible for transferring massive amounts of energy from lower to upper levels on the food chain.

Sand lance have a few interesting and rare characteristics. They alternate between schooling and foraging in the upper water column and extended periods of being almost completely buried in sand. For that, they rely on sand of a particular grain size and with very little organic content. It’s the kind of sand that defines large areas of the Stellwagen Bank.

Surprisingly little is known about the ecology and ecosystem importance of this sand lance species, although research on its European relatives (A. tobianus, A. marinus) is more advanced. In particular, experiments on early life stages of Northern sand lance have been lacking, save for some pioneering work on rearing methods of the related A. americanus (Smigielski et al. 1984). One question that was of particular interest to our lab involved the potential sensitivity of this fish species to carbon dioxide (CO2). That’s due to two other interesting and rare characteristics of sand lance. They spawn in late fall and winter in cold (and still cooling) waters, which is why their eggs and larvae develop extremely slow compared to other, more typical spring and summer spawning species. In addition, the species is found not in nearshore, but offshore coastal waters, where smaller seasonal and daily CO2 fluctuations more closely resemble oceanic conditions. Could sand lance offspring be particularly sensitive to higher levels of oceanic carbon dioxide predicted during the next 100 to 300 years as climate change effects intensify?


Sand lance caught on Stellwagen Bank in November 2014
Adult sand lance, shown here, is the favorite food for whales, seals, tuna and seabirds. Photo: Hannes Baumann
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Early results suggest that sand lance larva, shown in closeup, are particulary sensitive to higher levels of carbon dioxide. Photo courtesy of Hannes Baumann

Over the past two years (2016-17), we successfully found and sampled spawning ripe sand lance on Stellwagen Bank during a narrow window in late November. Eggs and sperm from adults were removed on board or after being transported live to our laboratory at UConn Avery Point. We reared newly fertilized embryos to hatch and to the feeding larval stage, under different sets of temperature and CO2 conditions, measuring survival and growth traits along the way.

Our experiments are still ongoing, and rearing protocols are being improved.

The preliminary findings, however, are stunning. Survival to hatch was dramatically reduced under elevated and high compared to baseline CO2 conditions. It was severely lowered at higher (10°C or 50°F) compared to lower temperatures (5°C or 41°F). Our second experiment this year appears to repeat this pattern. If these results continue, that would mean sand lance is one of the most CO2-sensitive species studied to date.

General interest in sand lance goes beyond its sensitivity to carbon dioxide. Given the species importance for the ecosystem and coastal economy, there are now increasing efforts to better understand sand lance feeding ecology, distribution and relationship to the rest of the food web. In this regard, funding of our project by the Northeast Sea Grant Consortium proved prescient and a seed for subsequent grants from MIT Sea Grant and the Bureau of Energy Management (BOEM) to continue the work. Surely, the groundswell of interest in sand lance is commensurate with its importance and will enable insights into better management strategies for sensitive ecosystems like those along the U.S. Atlantic coast.


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This graphic shows survival to hatch rates of Northern sand lance embryos reared at three carbon dioxide levels and two temperatures. Graphic: Hannes Baumann

Collaborators on this project are: D. Wiley of the National Oceanic and Atmospheric Administration-Stellwagen Bank National Marine Sanctuary; P. Valentine of the U.S. Geological Survey; and S. Gallagher and J. Llopiz, both of the Woods Hole Oceanographic Institution.

[Lab news] Live, feeding sand lance larvae

17 January 2018. Since November 2017, we have ongoing experiments with offspring of Northern sand lance (Ammodytes dubius), a winter-spawning forage fish of ecological importance along the North-American Atlantic coast. The clip below shows larvae almost two months after fertilization, developing nicely in 5C water and feeding actively on live rotifers. The experiments, led by Chris Murray for his PhD research, study the CO2 sensitivity of this species in our factorial larval rearing system. To our knowledge, this is the first time that this particular species has been reared that far under experimental conditions. Have a look!

Feeding sand lance
Sand lance (Ammodytes dubius) larvae feeding in green water on rotifers

[Lab news] Jake graduates with his Master’s degree!

Jacob-Snyder

Mumford Cove Oct 9th 2015

15 December 2017. The whole Baumann lab joins in congratulating Jake on his successful graduation with his Master’s degree from UConn! Jake embodied the spirit of a great student and team member, one who did not only seek to get something from the place he spent two years of his life but also one who left a great deal for us to remember. A wizard behind the camera, Jake has continuously enriched our lab with pictures that truly stand out and for which we will always be grateful. Jake helped in every aspect of the lab, but was particularly active in maintaing our monitoring efforts in Mumford Cove. For that, too, we are very grateful.

For his Master’s thesis, Jake painstakingly took it upon himself to retrieve and digitize the 40+ year time series of environmental observations from Project Oceanology, an ocean literacy organization that has been taking middle and high school students out to sea for decades. For the first time, his work allowed a quantitative evaluation of these data and a glimpse into the decadal changes in abiotic and biotic conditions in nearshore waters of Eastern Long Island Sound.

His Masters Thesis
Analysis of a Newly Digitized Long-Term Dataset of Environmental Observations from Long Island Sound
is accessible via the OpenCommons Site of the UConn Library.


During his time at the Baumann lab, Jake also conducted an experiment on potential maternal effects and their influence on offspring CO2 sensitivity, which was recently published in the Journal of Experimental Marine Biology and Ecology


Below is one of Jake’s timeless pictures of schooling juvenile Atlantic silversides. Many more pictures can be admired in our Imagery section or on Jake’s own Photography website RedSkiesPhotography

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On 12 September 2017, young-of-the-year Atlantic silversides (Menidia menidia) school in nearshore waters (Photo: Jacob Snyder, Bluff Point, CT)