Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Instruments
• Project Information
• Funding

Year-round variation in relative light intensity reaching the benthos on four coralline rocky reef sites in Sitka Sound, AK.

Methodology: 

Sampling and analytical procedures:

Year-round variation in relative light intensity reaching the benthos on coralline algal reefs in Sitka Sound, AK was measured using submersible pendant light loggers (Onset HOBO). From 2017-2020, we intermittently deployed two light loggers at ~7m depth (MLLW) at each of four rocky reef sites with high coralline algal cover and varied kelp canopy cover (Harris Is.: 57.032N, 135.277W; Breast Is.: 57.039N, 135.333W; Samsing Pinnacle: 56.988N, 135.357W; Sandy Cove: 56.986N, 135.321W; Fig. A.1). At each site, both loggers were placed within 1m of each other, oriented to face the water surface, and programmed to record light intensity (lux; lumen m-2) every 30 min. The light loggers were cleaned every 1-3mo, although overall fouling was low.

Problem report:

Gaps in sampling data occur when loggers were retrieved for cleaning and data download. Otherwise should be continuous, with data logged every 30min.

Processing notes from researcher:

Data downloaded from loggers using HOBOware software (Onset Computer Corporation, v3.7.22

BCO-DMO processing notes:

- Added UTC datetime 

- Converted local time to YYYY-MM-DD format, changed the column name to timestamp_local_akst, and removed the original timestamp column

- Rounded temp_F column to 4 digits past decimal point

NSF Award Abstract:
High latitude kelp forests support a wealth of ecologically and economically important species, buffer coastlines from high-energy storms, and play a critical role in the marine carbon cycle by sequestering and storing large amounts of carbon. Understanding how energy fluxes and consumer-resource interactions vary in these kelp communities is critical for defining robust management strategies that help maintain these valuable ecosystem services. In this integrated research and education program, the project team will investigate how consumer populations respond to variability in temperature, carbonate chemistry and resource quality to influence the food webs and ecosystem stability of kelp forests. A comprehensive suite of studies conducted at the northern range limit for giant kelp (Macrocystis pyrifera) in SE Alaska will examine how kelp communities respond to variable environmental conditions arising from seasonal variability and changing ocean temperature and acidification conditions. As part of this project, undergraduate and high school students will receive comprehensive training through (1) an immersive field-based class in Sitka Sound, Alaska, (2) intensive, mentored research internships, and (3) experiential training in science communication and public outreach that will include a variety of opportunities to disseminate research findings through podcasts, public lectures and radio broadcasts.

Consumer-resource interactions structure food webs and govern ecosystem stability, yet our understanding of how these important interactions may change under future climatic conditions is hampered by the complexity of direct and indirect effects of multiple stressors within and between trophic levels. For example, environmentally mediated changes in nutritional quality and chemical deterrence of primary producers have the potential to alter herbivory rates and energy fluxes between primary producers and consumers, with implications for ecosystem stability. Moreover, the effects of global change on primary producers are likely to depend on other limiting resources, such as light and nutrients, which vary seasonally in dynamic, temperate and high latitude ecosystems. In marine ecosystems at high latitude, climate models predict that ocean acidification will be most pronounced during the winter months, when primary production is limited by light. This project is built around the hypothesis that there could be a mismatch in the energetic demands of primary consumers caused by warming and ocean acidification and resource availability and quality during winter months, with cascading effects on trophic structure and ecosystem stability in the future. Through complementary lab and field experiments, the project team will determine 1) how temperature and carbonate chemistry combine to affect primary consumer bioenergetics across a diversity of species and 2) the indirect effects of ocean acidification and warming on primary consumers via environmentally mediated changes in the availability, nutritional quality and palatability of primary producers across seasons. Using the data from the laboratory and field experiments, the project team will 3) construct a model of the emergent effects of warming and ocean acidification on trophic structure and ecosystem stability in seasonally dynamic, high latitude environments.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.