14 June 2018. Members of the Baumann and Mason lab went on a trip to Mumford Cove, today, and Chris Tsang went along with his GoPro. Thanks to Charlie, the skipper, the ride was smooth and a pleasure, a swapping our pH, Temperature, oxygen, and salinity sensor was successfully swapped with a new one recording for the next weeks in 30 minute intervals. Wes Hoffman from the Mason lab, collected zooplankton with a Bongo-net. Sydney Stark, our NSF-REU student this summer, came along just for the fun.
We are overjoyed to announce that NSF is funding a new and collaborative research project to look at the genomic underpinning of local adaptation in the Atlantic silverside! Check out below for a first glimpse of the project website.
NSF-OCE #1756751 The genomic underpinnings of local adaptation despite gene flow along a coastal environmental cline (2018-2021)
Oceans are large, open habitats, where it was previously believed that the lack of obvious barriers to dispersal would result in extensive mixing, thereby preventing organisms from adapting genetically to particular habitats. It has recently become clear, however, that many marine species are subdivided into multiple populations that have evolved to thrive best under contrasting local environmental conditions. Nevertheless, we still know very little about the genomic mechanisms that enable divergent adaptations in the face of ongoing intermixing.
This project focuses on the Atlantic silverside (Menidia menidia), a small estuarine fish that exhibits a remarkable degree of local adaptation in growth rates and a suite of other traits tightly associated with a climatic gradient across latitudes. Decades of prior lab and field studies have made M. menidia one of the marine species for which we have the best understanding of evolutionary tradeoffs among traits and drivers of selection causing adaptive divergence. Yet, the underlying genomic basis is so far completely unknown.We will integrate whole genome sequencing data from wild fish sampled across the distribution range with breeding experiments in the laboratory to decipher these genomic underpinnings. This will provide one of the most comprehensive assessments of the genomic basis for local adaptation in the oceans to date, thereby generating insights that are urgently needed for better predictions about how species can respond to rapid environmental change. The project will provide interdisciplinary training for a postdoc as well as two graduate and several undergraduate students from underrepresented minorities. The findings will also be leveraged to develop engaging teaching and outreach materials (e.g. a video documentary and popular science articles) to promote a better understanding of ecology, evolution, and local adaptation among science students and the general public.
The project is organized into four interconnected components
Part 1 examines fine-scale spatial patterns of genomic differentiation along the cline to a) characterize the connectivity landscape, b) identify genomic regions under divergent selection, and c) deduce potential drivers and targets of selection by examining how allele frequencies vary in relation to environmental factors and biogeographic features.
Part 3 integrates patterns of variation in the wild (part 1) and the mapping of traits under controlled conditions (part 2) to a) examine how genomic architectures underlying local adaptation vary across gene flow regimes and b) elucidating the potential role of chromosomal rearrangements and other tight linkage among adaptive alleles in facilitating adaptation.
Part 4 examines dispersal – selection dynamics over seasonal time scales to a) infer how selection against migrants and their offspring maintains local adaptation despite homogenizing connectivity and b) validate candidate loci for local adaptation.
This research feature makes the case for multistressor research to a broad general audience and introduces our NSF project and its participants. Download the feature by clicking on the pictures or the link below.
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.
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.”
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?
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.
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.
Somewhere after Richmond, VA, the sun sets and traffic on the I-95 begins moving better. At long last. The four people in the burgundy Dogde Challenger have all already cycled through their driving shifts once and dare an impatient glance at the time left. Still more than 8 hours. More than 8 hours to reach this very special location at the Atlantic coast – Jekyll Island, Georgia. In the trunk of the car a jumble of coolers and a beach seine, buckets, air pumps, and hoses topped with the crumpled witnesses of roadside dining. This is no ordinary road trip.
We, that are Aryn and Nicholas from the Therkildsen lab of Conservation Genetics lab at Cornell University and James and Hannes from the Fish Ecology Lab here at UConn; we went on this road trip to catch live, spawning ripe Atlantic silversides from the southern edge of the species distribution. We then intended to bring these fish back to UConn alive, sample another population from the south shore of Long Island (Patchogue, NY) and produce genetic crosses of these populations.
The broad goal of our expanding collaborative efforts with our geneticist friends from Cornell is the creation of an annotated genome of this species, which will be an important milestone in deepening or understanding of the molecular and genetic responses of organisms to local selection regimes and marine climate change. Given the Atlantic silverside’s ecological importance as an abundant forage fish along the American east coast and it’s rich history as a model organism in evolutionary and ecological studies, the annotated genome is the next logical step.
Even at hindsight, the plan still seems a little insane. But it worked. We indeed managed to catch spawning silversides at the Georgia site and then transported them immediately back to our Rankin Lab, which involved another 17 hours of driving back. After securing samples from Patchogue, we indeed managed to cross single parents from each site to produce full-sib crosses that will later be used to produce what geneticist call a linkage map. Other across and within-population crosses will be used to study gene expression at two different temperatures or raise adults for producing an F2 generation.
The silverside larvae are currently well, feeding, and growing up nicely. We all cross fingers for this enterprise to end in good samples and a step forward for genetic studies on a marine fish.
A newly hatched silverside larvae with a twist. It's a haploid specimen, produced by fertilizing eggs with UV-treated sperm.
James Harrington carefully replacing water in the transport coolers for the fish. All fish survived the transport.
The Jekyll crew Hannes, James, Nicholas, and Aryn (from left to right)
The daunting view of the road trip on 10 - 12 May 2017. 34h of driving and way too little sleep in just two days.
Adult silversides from Jekyll Island, GA, swimming in our holding tanks in the Rankin Lab at UConn
On the morning of 11 May 2017, our old beach seine is drying on the beach park of Jekyll Island, GA. After its last successful trip, the 9 year old gear has now been retired.
Andrew's Beach on Jekyll Island, GA, on 11 May 2017.
NOAA sanctuaries just published a little blurb online, introducing sand lance and it’s importance to the Stellwagen Bank National Marine Sanctuary, including a small section on the current research efforts funded by NOAA Regional SeaGrant.
“To that end, the team is collaborating with scientists from the University of Connecticut (UConn). UConn study members transport live-caught sanctuary sand lance to their lab, where further generations of sand lance are raised. The resulting larval sand lance are raised in high-tech rearing facilities that can be adjusted to mimic future ocean conditions.”
4th time’s the charm: sampling spawning ripe sand lance on Stellwagen Bank
Early morning on 2 December 2016, we left Scituate, MA, for the forth time this year, heading towards Stellwagen Bank in search of spawning ripe Northern sand lance (Ammodytes dubius), a winter spawning forage fish of great importance to the Stellwagen Bank National Marine Sanctuary and the object of latest research efforts. While during the last three cruises in late October and November, we saw a progression of ripening in the specimens, up to now we didn’t actually find spawning ripe individuals. Today, though, things are different, and when the first sand lance appear in our beam trawl, we immediately know that today we’ve been at the right time and at the right place.
It seemed an ambitious dream not too long ago, but now we’re happy report that we’ve started an experiment on sand lance embryos in our lab. Thanks to Chris Murray, David Wiley, Mike Thompson, captain Steve and his deckhand Matt for the successful trip!
Check out some footage of the trip and the beam trawl operation on board of captain Steve’s fishing vessel
On 27 October 2016, Hannes, Chris and Julie joined researchers from the Stellwagen Bank National Marine Sanctuary (David Wiley, Anne-Marie Runfola, Brad Cabe, Michael Thompson), the USGS (Page Valentine, Dann Blackwood) and the crew of the R/V Auk (Dave Slocum, James Stasinos) to embark on our first of five total sampling missions in this enigmatic marine habitat. Our goal, catching live Northern sand lance, Ammodytes dubius, the so critical forage fish species that is referred to as the “backbone of the sanctuary”, because all kinds of marine predators from whales to tuna to seabirds gather on the bank to feast on them.
Our renewed efforts are part of our recently funded NOAA Regional SeaGrant Project to investigate the effects of ocean warming, acidification and low oxygen on sand lance early life stages.
As before, we first started by deploying a Seaboss sediment grab, which allows our colleagues from the USGS to characterize sediment types in association with the occurrence of sand lance. In addition, however, we brought a small beam trawl along for the first time to find out, whether we could more effectively catch sand lance and then transport them live to our seawater facility at UConn Avery Point. We are happy report that the efforts by all have paid off and that there are now ~ 180 adult ripening sand lance swimming in our tanks. Thanks all, see you again for the second survey in a few weeks!
Check out the video below, made from clips of no less than five different GoPro’s (if you listen carefully, around 2:40 into the clip you’ll hear the singing of some nearby humpback whales):
Seasonal dynamics in Atlantic Silverside abundance, spawning, and offspring sensitivity to low pH and oxygen
The Summer Undergraduate Research Fund (SURF) offers a summer stipend of up to $3,500 + $500 research. The Evolutionary Fish Ecology Lab offers a variety of suitable topics for undergraduates to work on.
Deadline for applications is January, 20th 2017.