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News from ACER

Friday, November 4th, 2016

The summer and early fall has been a busy time for many of ACER’s scientists and staff. With the second year coming to an end, we take a look back over the past few months to share all that we have accomplished.

Field work has taken precedence with everyone hitting the water in May and June and again in September. ACER had 2 cruises to the Chandeleurs Islands, on the Charter boat Southern Way, where the Infauna, Microbes and Wetlands groups worked together to sample the nearshore habitats along this remote island chain. Collaborating with CONCORDE on their summer cruise, the Microplankton group set out on the Pt. Sur to sample the Mississippi-Alabama shelf for phytoplankton. And the Consumer group surveyed the fish and sharks with their trawling and bottom longlining activities along the Chandeleur Islands and within Mississippi Sound and Mobile Bay.

Chandeleur cruise
ACER Researchers, Students and Staff get ready for their summer sampling cruise to the Chandeleur Islands.

In between boat trips, many of ACER’s groups have been working on their laboratory experiments many of which take place at DISL’s large outdoor mesocosm facility. Here are a few highlights from the ACER groups:

Spartina flowering
ACER PI Dr. Randall Hughes collecting flowers to look at reproduction potential of Spartina in one of the mesocosm tanks.

The Wetlands group got back from their fall cruise to the Chandeleur Islands and immediately started breaking down their yearlong mesocosm experiment looking at how plant diversity affects their response to oiling. Collaborating with the Nitrogen group they took final samples, collecting data on a variety of plant metrics (growth, density, reproduction, nutrient levels), microbial community composition, sediment nutrient fluxes and denitrification rates. They also tapped the expertise of ACER’s Microbes group to sample algal mats that unexpectedly developed in the mesocosms. ACER Wetland group Project Manager Whitney Scheffel said of the experience “When designing and implementing a large scale project like this one, there are bound to be multiple complications and headaches, but our groups were able to come together and share their expertise and ideas that ultimately made this project a success. We are excited to see what the data tell us about the resilience of our coastal wetland habitats.”

Oyster mesocosms
ACER Post-Doctoral Researcher Meaghan Schrandt and Hunter King of DISL Tech Support Department setting up the shelving units for the Oyster groups mesocosm experiments.

The Oyster group spent the summer building a new closed, re-circulating aquarium system at the outdoor mesocosm facility so that they could begin their experiments this fall. They used 11 different genetic mixes (monocultures and polycultures) of oysters and have exposed them to 6 different water treatments of varying salinity and oil exposure: they have a total of 330 tanks and 15,840 oysters! Every day the shelving systems have been monitored for salinity and water levels and the oysters are fed a diet of mixed algae twice a day. ACER Post-Doctoral Researcher Dr. Meagan Schrandt said at the end of the experiment, all of the oysters will be counted to compare the number of live and dead oysters in the treatments and two subsets of samples will be taken: one for measuring shell growth and one for looking at general oyster condition using a formula relating the amount of tissue to the amount of shell for each oyster.

Consumer tanks
Reflection of ACER Technician Scott Alford checking on a red drum in one of the Consumer group’s oiling experiments. Photo credit: Scott Alford

The Consumer group has spent the summer and fall on their mesocosm experiments investigating how oil affects the feeding habits of fish and crabs. Comparing behaviors of a single predator system to a multiple predator system, they hope to see how oil may impact the productivity of coastal food webs. ACER technician Scott Alford expects to wrap things up by the end of the year and is excited to see how coastal food webs may have been impacted by the Deepwater Horizon oil spill. Scott said one of the most interesting things he has seen so far is how different predators interact and their different styles of hunting their prey.

A successful field season is inevitably followed by a winter of data analysis, interpretation and writing. With numerous samples to process and data to crunch, ACER Researchers, Students and Staff will be staying very busy during the next few months. We look forward to sharing the results of these activities with you in the spring.