Selected Publications

Carbon offsetting—receiving credit for reducing, avoiding, or sequestering carbon—has become part of the portfolio of solutions to mitigate carbon emissions, and thus climate change, through policy and voluntary markets, primarily by land-based re- or afforestation and preservation. However, land is limiting, creating interest in a rapidly growing aquatic farming sector of seaweed aquaculture. Synthesizing data from scientific literature, we assess the extent and cost of scaling seaweed aquaculture to provide sufficient CO2eq sequestration for several climate change mitigation scenarios, with a focus on the food sector—a major source of greenhouse gases. Given known ecological constraints (nutrients and temperature), we found a substantial suitable area (ca. 48 million km2) for seaweed farming, which is largely unfarmed. Within its own industry, seaweed could create a carbon-neutral aquaculture sector with just 14% (mean = 25%) of current seaweed production (0.001% of suitable area). At a much larger scale, we find seaweed culturing extremely unlikely to offset global agriculture, in part due to production growth and cost constraints. Yet offsetting agriculture appears more feasible at a regional level, especially areas with strong climate policy, such as California (0.065% of suitable area). Importantly, seaweed farming can provide other benefits to coastlines affected by eutrophic, hypoxic, and/or acidic conditions, creating opportunities for seaweed farming to act as “charismatic carbon” that serves multiple purposes. Seaweed offsetting is not the sole solution to climate change, but it provides an invaluable new tool for a more sustainable future.
In Current Biology,2019

Humans interact with the oceans in diverse and profound ways. The scope, magnitude, footprint and ultimate cumulative impacts of human activities can threaten ocean ecosystems and have changed over time, resulting in new challenges and threats to marine ecosystems. A fundamental gap in understanding how humanity is affecting the oceans is our limited knowledge about the pace of change in cumulative impact on ocean ecosystems from expanding human activities – and the patterns, locations and drivers of most significant change. To help address this, we combined high resolution, annual data on the intensity of 14 human stressors and their impact on 21 marine ecosystems over 11 years (2003–2013) to assess pace of change in cumulative impacts on global oceans, where and how much that pace differs across the ocean, and which stressors and their impacts contribute most to those changes. We found that most of the ocean (59%) is experiencing significantly increasing cumulative impact, in particular due to climate change but also from fishing, land-based pollution and shipping. Nearly all countries saw increases in cumulative impacts in their coastal waters, as did all ecosystems, with coral reefs, seagrasses and mangroves at most risk. Mitigation of stressors most contributing to increases in overall cumulative impacts is urgently needed to sustain healthy oceans.
In Scientific Reports, 2019

Reproducibility has long been a tenet of science but has been challenging to achieve—we learned this the hard way when our old approaches proved inadequate to efficiently reproduce our own work. Here we describe how several free software tools have fundamentally upgraded our approach to collaborative research, making our entire workflow more transparent and streamlined. By describing specific tools and how we incrementally began using them for the Ocean Health Index project, we hope to encourage others in the scientific community to do the same—so we can all produce better science in less time.
In Nature Ecology & Evolution, 2017

Recent Publications

More Publications

. Changes in ocean health in British Columbia from 2001 to 2016. In PLoS ONE, 2020.

PDF Code Project

. Blue Growth Potential to Mitigate Climate Change through Seaweed Offsetting. In Current Biology, 2019.

PDF Project

. Recent pace of change in human impact on the world’s ocean. In Scientific Reports, 2019.

PDF Code Dataset

. Quantifying uncertainty in the wild‐caught fisheries goal of the Ocean Health Index. In Fish & Fisheries, 2019.

PDF Project

. Trade‐offs for data‐limited fisheries when using harvest strategies based on catch‐only models. In Regional Environmental Change, 2018.

PDF Project

. A pan-Arctic assessment of the status of marine social-ecological systems. In Regional Environmental Change, 2018.

PDF Project

. Cumulative human impacts in the Bering Strait Region. In Ecosystem Health and Sustainability, 2017.

PDF Project

. Drivers and implications of change in global ocean health over the past five years. In PLoS ONE, 2017.

PDF Code Dataset Project Interactive App

. Our path to better science in less time using open data science tools. In Nature Ecology & Evolution, 2017.

PDF Project

. Aligning marine species range data to better serve science and conservation. In PLoS ONE, 2017.

PDF Code Project Interactive Shiny App

Recent & Upcoming Talks

Creating a personal website with blogdown
Mar 14, 2018 12:00 AM
Ocean Health Index in the US Northeast
May 2, 2017 12:00 AM

Recent Posts

The aim of this project was to evaluate whether or not geotagged social media data can be useful in providing insight into a region’s “Sense of Place” using Santa Barbara as a case study. How and where people experience and value coastal and ocean areas can reveal places we deem special. Sense of place can be defined as the connection people feel to their geographic surroundings, including both the natural and built environment.


This blog post was originally written for A significant portion of my work on the Ocean Health Index (OHI) involves working with raster data, a specific type of spatial data where values are held in grid cells. The data I work with varies from high resolution, remotely sensed data on sea surface temperature to coarse, modeled data on global fish catch. When I was working on the global assessment, I dealt with raster data at a global scale.


Creating a dynamic figure using gganimate and tweenr.



Cumulative Human Impacts

Estimating and tracking human impacts on marine ecosystems

Data-Limited Fisheries

A working group focused on developing new methods for assessing the status of data poor fish stocks globally.

Ocean Health Index

The Ocean Health Index is a framework to measure the health of the oceans. Understanding the state of our oceans is a first step towards ensuring they can continue providing humans benefits now and in the future.



Intro to Spatial Analysis in R (focus on rasters)

Open Data Science Training at the University of Queensland Brisbane, Queensland, Australia June 18 - 19, 2019

Software Carpentry for R at Woods Hole Oceanographic Institute Woods Hole, MA October 22 - October 23, 2018

Data Wrangling & Visualization Taught at the Monterey Bay Aquarium Research Institute Software Carpentry Moss Landing, CA November 30 - December 1, 2017

Data Wrangling and Visualization (SWC for Ecology Materials) UC Merced Software Carpentry Merced, CA August 18, 2017