Arctic Field Projects

Project Title: Ocean Acidification: Century Scale Impacts to Ecosystem Structure and Function of Aleutian Kelp Forests (Award# 1316141)

PI: Steneck, Robert S (
Phone: (207) 563.8315 
Institute/Department: U of Maine, School of Marine Sciences 
IPY Project?
Funding Agency: US\Federal\NSF\GEO\OPP\ARC\ANS
Program Manager: Dr. Henrietta Edmonds ( )
Discipline(s): | Biology |

Project Web Site(s):

Science Summary:
Marine calcifying organisms are most at risk to rapid ocean acidification (OA) in cold-water ecosystems. The investigators propose to determine if a globally unique and widespread calcareous alga in Alaska's Aleutian archipelago, Clathromorphum nereostratum, is threatened with extinction due to the combined effects of OA and food web alterations. C. nereostratum is a slow growing coralline alga that can live to at least 2000 years. It accretes massive 'bioherms' that dominate the region's rocky substrate both under kelp forests and deforested sea urchin barrens. It develops growth bands (similar to tree rings) in its calcareous skeleton, which effectively record its annual calcification rate over centuries. Pilot data suggest the skeletal density of C. nereostratum began to decline precipitously in the 1990s in some parts of the Aleutian archipelago. The investigators now propose to use high-resolution microscopy and microCT imaging to examine how the growth and skeletal density of C. nereostratum has changed in the past 300 years (i.e., since the industrial revolution) across the western Aleutians. They will compare their records of algal skeletal densities and their variation through time with reconstructions of past climate to infer causes of change. In addition, the investigators will examine whether the alga's defense against grazing by sea urchins is compromised by ongoing ocean acidification. The investigators will survey the extent of C. nereostratum bioerosion occurring at 20 sites spanning the western Aleutians, both inside and outside of kelp forests. At each site they will compare these patterns to observed and monitored ecosystem trophic structure and recent C. nereostratum calcification rates. Field observations will be combined with laboratory experiments to determine if it is a decline in the alga's skeletal density (due to recent OA and warming), an increase in grazing intensity (due to recent trophic-level dysfunction), or their interactive effects that are likely responsible for bioerosion patterns inside vs. outside of forests. By sampling C. nereostratum inside and outside of forests, they will determine if kelp forests locally increase pH via photosynthesis, and thus buffer the effects of OA on coralline calcification. The combination of field observations with laboratory controlled experiments, manipulating CO2 and temperature, will help elucidate drivers of calcification and project how these species interactions will likely change in the near future. The project will provide the first in situ example of how ongoing ocean acidification is affecting the physiology of long-lived, carbonate producing organisms in the subarctic North Pacific. It will also be one of the first studies to document whether OA, ocean warming, and food web changes to ecological processes are interacting in complex ways to reshape the outcome of species interactions in nature. The project will support a postdoctoral investigator, and involve graduate and undergraduate students in the field work. The project will support research by a Native American undergraduate student and include outreach to coastal tribes and other members of the public.

Logistics Summary:
This project will determine how ocean acidification (OA) is altering the structure and function of Aleutian kelp forest ecosystems by reducing the resistance of a long-lived coralline alga to deep grazing herbivores. In 2014 a field team of 10 will conduct field studies from June to early August in kelp forests of the subarctic North Pacific Ocean, building upon previous research conducted under NSF grant 0647663. This 3-year project involving field surveys, field collections and coupled laboratory experiments involving the crustose coralline algae (CCA) Clathromorphum nereostratum (from Alaska) and C. compactum (from Maine) to document the effects of ongoing ocean acidification and food web changes on these important reefbuilders. One cruise in the Aleutian archipelago of the subarctic North Pacific will take place in 2014. Using SCUBA, researchers will conduct field surveys and collections of coralline algae at 20 remote, shallow water kelp forest sites throughout the western portion of the Aleutian archipelago in Alaska. The sites, both inside and outside of kelp forests, will be along a 700 km transect through the western portion of the Aleutian archipelago, from Adak to Attu Island. Researchers will travel short distances from the cruise (UNOLS) vessel to field sites using small, deployable skiffs. At each site, researchers will conduct visual surveys of coralline algae, kelp, and sea urchins following established protocols. At each study site, researchers will collect long-lived (300-year old) coralline algae, lift them to the surface using air lift-bags, and at the surface lift them into the vessel using a ship-based crane. Once aboard the ship, coralline algae (80 specimens from each study site) would be sectioned on deck using a diamond saw, polished, and packaged for transport back to Maine. Researchers will also conduct shipboard aquarium feeding assays using living coralline algae and sea urchins to elucidate the mechanisms potentially driving patterns observed in field surveys.

All logistics will be organized by the researcher and paid through the grant.
SeasonField SiteDate InDate Out#People
2014Alaska - ADK2007 / 22 / 2014 07 / 22 / 201410
2014Alaska - ALD1007 / 15 / 2014 07 / 16 / 201410
2014Alaska - Bat Island07 / 09 / 2014 07 / 11 / 201410
2014Alaska - Blacks Beach07 / 17 / 2014 07 / 19 / 201410
2014Alaska - Kirilof Point 07 / 09 / 2014 07 / 10 / 201410
2014Alaska - Kirilof Rocks Kelp Forest 07 / 09 / 2014 07 / 10 / 201410
2014Alaska - Kirilof Rocks Lebednik 07 / 09 / 2014 07 / 10 / 201410
2014Alaska - Mutt Cove Point 07 / 12 / 2014 07 / 13 / 201410
2014Alaska - NE Corner 07 / 15 / 2014 07 / 15 / 201410
2014Alaska - Nizki Deep07 / 15 / 2014 07 / 16 / 201410
2014Alaska - Octopus Garden 07 / 07 / 2014 07 / 21 / 201410
2014Alaska - OGA107 / 07 / 2014 07 / 08 / 201410
2014Alaska - OGA3a07 / 21 / 2014 07 / 21 / 201410
2014Alaska - OGA507 / 07 / 2014 07 / 08 / 201410
2014Alaska - PP607 / 17 / 2014 07 / 19 / 201410
2014Alaska - Puffin Point07 / 14 / 2014 07 / 16 / 201410
2014Alaska - Tanaga Hot Springs07 / 05 / 2014 07 / 06 / 201410
2014Alaska - TGH507 / 05 / 2014 07 / 06 / 201410
2014Alaska - TGH707 / 05 / 2014 07 / 06 / 201410
2014Alaska - Yippee Shoals07 / 04 / 2014 07 / 04 / 201410

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