Table of Contents

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

These data are published in Hirsh et al., see related publications section.

A bottom-mounted 1200 kHz Teledyne-RDI workhorse ADCP (1 m vertical resolution) was deployed <10 m from the outside kelp mooring site (36° 37.342’ N, 121° 54.049’ W) from August 8 to October 5, 2018, coinciding with the second ADCP deployment inside the kelp forest.

There was only one deployment at the outside mooring. There is no current data available for the outside mooring before August 8 due to limited instrument availability.

• Deployment 1 (19 x1 meter bins):
  • Bin depths (meters above bottom):
    1.56
    2.56
    3.56
    4.56
    5.56
    6.56
    7.56
    8.56
    9.56
    10.56
    11.56
    12.56
    13.56
    14.56
    15.56
    16.56
    17.56
    18.56
    19.56

Current directions were corrected for declination: true north was 13.12° degrees from magnetic north.

Velocity measurements from the ADCP deployment was rotated into cross-shore and alongshore velocity components using the principal axes calculated (princax function in Matlab) for the deployment. Individual current profiles were smoothed using a cubic smoothing spline (Matlab csaps package; smoothing parameter = 0.8).

• Outside Kelp Forest: August 8 - October 5, 2018
  • Alongshore: Principal axis = 137°
  • Cross-shore: Principal axis = 47°

The top 10% of the water column and velocity > 0.3 m/s was replaced with NaN.

BCO-DMO Processing Notes:

• Adjusted column headers to comply with database requirements
• Converted Timestamp to ISO format
• Merged cross-shore and alongshore dataset, reformatted the datasets to convert zbins into 1 column.
• Added collumns: Mooring_ID, Deployment_ID and Velocity_Components

NSF Award Abstract:
Kelp forest ecosystems are of ecological and economic importance globally and provide habitat for a diversity of fish, invertebrates, and other algal species. In addition, they may also modify the chemistry of surrounding waters. Uptake of carbon dioxide (CO2) by giant kelp, Macrocystis pyrifera, may play a role in ameliorating the effects of increasing ocean acidity on nearshore marine communities driven by rising atmospheric CO2. Predicting the capacity for kelp forests to alter seawater chemistry requires understanding of the oceanographic and biological mechanisms that drive variability in seawater chemistry. The project will identify specific conditions that could lead to decreases in seawater CO2 by studying 4 sites within the southern Monterey Bay in Central California. An interdisciplinary team will examine variations in ocean chemistry in the context of the oceanographic and ecological characteristics of kelp forest habitats. This project will support an early career researcher, as well as train and support a postdoctoral researcher, PhD student, thesis master's student, and up to six undergraduate students. The PIs will actively recruit students from underrepresented groups to participate in this project through Stanford University's Summer Research in Geosciences and Engineering (SURGE) program and the Society for Advancement of Hispanics/Chicanos and Native Americans in Science (SACNAS). In addition, the PIs and students will actively engage with the management community (Monterey Bay National Marine Sanctuary and California Department of Fish and Wildlife) to advance products based on project data that will assist the development of management strategies for kelp forest habitats in a changing ocean.

This project builds upon an extensive preliminary data set and will link kelp forest community attributes and hydrodynamic properties to kelp forest biogeochemistry (including the carbon system and dissolved oxygen) to understand mechanistically how giant kelp modifies surrounding waters and affects water chemistry using unique high-resolution measurement capabilities that have provided important insights in coral reef biogeochemistry. The project sites are characterized by different oceanographic settings and kelp forest characteristics that will allow examination of relationships between kelp forest inhabitants and water column chemistry. Continuous measurements of water column velocity, temperature, dissolved oxygen, pH, and photosynthetically active radiation will be augmented by twice-weekly measurements of dissolved inorganic carbon, total alkalinity, and nutrients as well as periods of high frequency sampling of all carbonate system parameters. Quantifying vertical gradients in carbonate system chemistry within kelp forests will lead to understanding of its dependence on seawater residence time and water column stratification. Additional biological sampling of kelp, benthic communities, and phytoplankton will be used to 1) determine contributions of understory algae and calcifying species to bottom water chemistry, 2) determine contributions of kelp canopy growth and phytoplankton to surface water chemistry, and 3) quantify the spatial extent of surface chemistry alteration by kelp forests. The physical, biological, and chemical data collected across multiple forests will allow development of a statistical model for predictions of kelp forest carbonate system chemistry alteration in different locations and under future climate scenarios. Threshold values of oceanographic conditions and kelp forest characteristics that lead to alteration of water column chemistry will be identified for use by managers in mitigation strategies such as targeted protection or restoration.