Branwen Williams

Branwen Williams
The Claremont Colleges · W.M. Keck Science Department

PhD

About

70
Publications
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Introduction
Branwen Williams is an environmental scientist at the Claremont Colleges, seeking to understand the role of humans in modifying our environment. She extracts environmental data from the skeletons of marine organisms, and interprets this data to tease apart natural changes in our environment from those that are caused by humans.

Publications

Publications (70)
Article
Full-text available
Plain Language Summary In the North Atlantic, nitrate is a key nutrient involved in regulating phytoplankton populations and is therefore also important for marine ecosystem dynamics and, potentially, oceanic carbon storage. Along the Labrador Shelf, near‐surface nitrate may be supplied by mixing from deeper waters or from its advection from relati...
Article
Full-text available
Massive, long-lived deep-sea red tree corals ( Primnoa pacifica ) form a solid, layered axis comprised of calcite and gorgonin skeleton. They are abundant on the outer continental shelf and upper slope of the Northeast Pacific, providing habitat for fish and invertebrates. Yet, their large size and arborescent morphology makes them susceptible to d...
Article
Rising atmospheric carbon dioxide is warming Arctic seawater at a rate twice the global average due to multiple positive feedbacks. Thus, warming is disproportionately influencing data-poor Arctic marine ecosystems. Subarctic flora are an important component of these ecosystems, along with the less biodiverse flora endemic to the Arctic. Warming wi...
Article
Full-text available
In order to fight against the spread of COVID-19, the most hard-hit countries in the spring of 2020 implemented different lockdown strategies. To assess the impact of the COVID-19 pandemic lockdown on air quality worldwide, Air Quality Index (AQI) data was used to estimate the change in air quality in 20 major cities on six continents. Our results...
Article
The Li/Mg, Sr/Ca and oxygen isotopic (δ18O) compositions of many marine biogenic carbonates are sensitive to seawater temperature. Corals, as cosmopolitan marine taxa with carbonate skeletons that can be precisely dated, represent ideal hosts for these geochemical proxies. However, efforts to calibrate and refine temperature proxies in cold-water c...
Article
High-resolution marine data are critical to evaluating anthropogenic impacts on our environment. Considering the spatial and temporal limitations of direct instrumental measurements, proxy data extracted from marine environmental archives are necessary to separate anthropogenic changes from those that would occur naturally. The majority of late-Hol...
Article
This study evaluates the presence of metal(loid) contamination from shrimp aquaculture effluent in a nearby mangrove ecosystem in Khung Krabaen Bay (KKB), Thailand. Our objectives were to: 1) examine how sediment metal(loid) concentrations change spatially in KKB relative to the aquaculture ponds; (2) compare mollusc trophic dynamics of elements as...
Article
Areas dedicated to shrimp aquaculture have increased dramatically over the last 50 years. Resultant land‐use changes directly threaten the extent of mangroves and yield conflicts on the discharge location of aquaculture effluent. Khung Krabaen Bay (KBB), Thailand, is reforesting mangroves while increasing the efficiency of shrimp aquaculture for lo...
Article
A solid understanding of global oceanic change throughout Holocene time is needed to contextualize and interpret recent observations of rapid warming (Moore, 2016), ocean acidification (Popova et al., 2014; Qi et al., 2017), increasing meltwater input (Halfar et al., 2013; Notz and Stroeve, 2016) and circulation changes (Liu et al., 2017; Rahmstorf...
Article
High-latitude climate reconstructions are essential for discerning anthropogenic climate change from natural climate variability. Since observational high-latitude climate records are rare prior to the satellite era, climate proxies such as the coralline algae Clathromorphum compactum are needed to generate these reconstructions. C. compactum is di...
Article
While the recent decline in the δ¹³C composition of oceanic dissolved inorganic carbon (DIC) can be attributed to increasing anthropogenic CO2 emissions (¹³C Suess effect), the causes of natural variability in the δ¹³C of oceanic DIC (δ¹³CDIC) are far less understood. Unfortunately, instrumental oceanic DIC measurements are not available prior to t...
Article
The stable isotope geochemistry of gorgonian octocoral skeletons facilitates detailed time series reconstructions of nutrient biogeochemistry. However, comparisons among reconstructions from different locations require realistic estimates of the uncertainty surrounding each measured geochemical value. Here, we determine quantitative uncertainties r...
Article
Compound-specific stable isotopes of amino acids (CSI-AA) from proteinaceous deep-sea coral skeletons have the potential to improve paleoreconstructions of plankton community composition, and our understanding of the trophic dynamics and biogeochemical cycling of sinking organic matter in the Ocean. However, the assumption that the molecular isotop...
Article
Full-text available
Accelerated warming and melting of Arctic sea-ice has been associated with significant increases in phytoplankton productivity in recent years. Here, utilizing a multiproxy approach, we reconstruct an annually resolved record of Labrador Sea productivity related to sea-ice variability in Labrador, Canada that extends well into the Little Ice Age (L...
Data
Supplementary Figure, Supplementary Note and Supplementary References
Article
Reconstructed sea surface temperatures (SSTs) derived from Mg/Ca measurements in nine encrusting coralline algal skeletons from the Aleutian archipelago in the northernmost Pacific Ocean reveal an overall increase in SST from 1665 to 2007. In the Aleutian SST reconstruction, decadal-scale variability is a transient feature present during the 1700s...
Article
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A concerted effort has begun to gather and preserve archives of marine samples and descriptive data, giving scientists ready access to insights on ancient environments.
Technical Report
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Deep-sea coral and sponge ecosystems are widespread throughout most of Alaska’s marine waters. In some places, such as the central and western Aleutian Islands, deep-sea coral and sponge resources can be extremely diverse and may rank among the most abundant deep-sea coral and sponge communities in the world. Many different species of fishes and in...
Conference Paper
Full-text available
The impacts of recent and future anthropogenic increases in atmospheric pCO2 causing ocean acidification and temperature on high-latitude oceans, and the marine organisms that inhabit them, are varied and poorly understood. The ecologically important crustose coralline alga Clathromorphum compactum may be particularly vulnerable to ocean acidificat...
Article
The depth of the thermocline and associated nitricline in the western Pacific warm pool (WPWP) vary over time in response to changes in larger ocean-atmosphere climate patterns. A shoaling of the nitricline in the WPWP brings nitrate-rich seawater ( > 4 μmol kg−1) above the base of the euphotic zone, stimulating primary productivity. Here, we test...
Article
An increased number of climate proxy records and more refined interpretation of proxy data are crucial to improve projections of future climate at high latitudes, where internal feedbacks amplify warming and established high-resolution climate archives are especially sparse. Encrusting coralline algae are being developed as a mid- to high- latitude...
Article
Full-text available
Records of high resolution climate variability in the past are essential to understanding the climate change observed today. This is particularly true for Arctic regions, which are rapidly warming. Prior to instrumental data, proxy records can be extracted from high-latitude climate archives to provide critical records of past Arctic climate variab...
Chapter
Full-text available
A number of marine and freshwater organisms, including scleractinian and proteinacious corals, coralline algae, sclerosponges, and bivalve mollusks, secrete skeletons that grow larger over time and may record environmental contaminants over the lifespan of an individual. Most of these organisms also form periodic growth patterns (growth increments,...
Article
Higher latitude oceanic and climatic reconstructions are needed to distinguish natural climate variability from anthropogenic warming in regions projected to experience significant increases in temperature during this century. Clathromorphum nereostratum is a long-lived coralline alga abundant along the Aleutian archipelago that records seasonal to...
Article
Over the last two decades, the skeletal remains of deep-sea corals have arisen as a geochemical archive of Pleistocene oceanographic change. Here we report the exploration of the isotopic composition of the carbonate-bound organic nitrogen (hereafter, CB-δ15N) in the deep-sea scleractinian coral Desmophyllum dianthus as a possible tool for reconstr...
Article
Full-text available
Adey, Walter H., Jochen Halfar, and Branwen Williams. The Coralline Genus Clathromorphum Foslie emend. Adey: Biological, Physiological,and Ecological Factors Controlling Carbonate Production in an Arctic-Subarctic Climate Archive. Smithsonian Contributions to the Marine Sciences, number 40, iv + 42 pages, 29 figures, 1 table, 2013.— The coralline a...
Conference Paper
Ocean acidification may inhibit calcification pathways of marine plants and animals. Recently, it has been suggested that aragonitic tropical corals and other marine calcifiers already exhibit declining calcification rates. Greater oceanic CO2 uptake at mid-to-high latitudes may result in greater inhibition of calcium carbonate secretion in subarct...
Article
Full-text available
Ocean acidification may have severe consequences for marine ecosystems; however, assessing its future impact is difficult because laboratory experiments and field observations are limited by their reduced ecologic complexity and sample period, respectively. In contrast, the geological record contains long-term evidence for a variety of global envir...
Article
Numerous oceanic passes along the Aleutian Island arc connect the northern North Pacific Ocean to the Bering Sea. Seawater moving through these passes is the dominant source of water along the eastern slope of the Bering Sea, an oceanographically and ecologically significant region that is already changing in response to increasing global temperatu...
Article
Bamboo corals (Order Gorgonacea, Family Isididae) are attractive prospects for deep-sea paleoceanographic reconstruction, capturing trace elements in their calcitic skeletons that may serve as environmental proxies with subdecadal resolution over multi-century timescales. We study the reproducibility and fidelity of trace-element profiles (Ba, Mg,...
Article
Full-text available
Bering Sea climate and ecosystem dynamics have recently undergone major changes that have affected seasonal sea ice distribution and marine life, including commercially important salmon fisheries. Unfortunately, long-term Bering Sea dynamics are poorly understood, largely because of an absence of high-resolution marine proxy archives. Here we prese...
Article
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Arctic Ocean freshening can exert a controlling influence on global climate, triggering strong feedbacks on ocean‐atmospheric processes and affecting the global cycling of the world’s oceans. Glacier‐fed ocean currents such as the Alaska Coastal Current are important sources of freshwater for the Bering Sea shelf, and may also influence the Arctic...
Article
Over the past decade coralline algae have increasingly been used as archives of paleoclimate information. Encrusting coralline algae, which deposit annual growth increments in a high Mg-calcite skeleton, are amongst the longest-lived shallow marine organisms. In fact, a live-collected plant has recently been shown to have lived for at least 850 yea...
Article
Full-text available
Proxy records can be derived from soft corals and black corals using minor and trace element measurements of the organic skeleton of these corals. Here, concentrations of Br, I, Pb, Mn, Cd, Zn, and B in the organic skeleton were determined using solution inductively coupled plasma-mass spectrometry (ICP-MS) in one black coral from 5 m depth and two...
Article
Full-text available
The oxygen isotopic composition and Mg/Ca ratios in the skeletons of long-lived coralline algae record ambient seawater temperature over time. Similarly, the carbon isotopic composition in the skeletons record δ13C values of ambient seawater dissolved inorganic carbon. Here, we measured δ13C in the coralline alga Clathromorphum nereostratum to test...
Article
Bamboo corals (Family Isididae) are attractive prospects for deep-sea paleoceanographic reconstruction because their simple skeletal architecture simplifies age assignment, while their calcite skeletons capture trace elements that may serve as environmental proxies. For slow growing proxies like deep corals, laser-ablation ICP-MS is an ideal techni...
Article
Full-text available
Oxygen isotopes and Mg/Ca ratios in long-lived coralline algae record ambient seawater temperature in their calcified tissues over time. Similarly, carbon stable isotopes (delta13C) in the calcified tissue may record delta13C values of ambient seawater dissolved inorganic carbon. Here, we measured delta13C in the coralline algae Clathromorphum nere...
Article
Full-text available
Long records of subsurface ocean observations are key to constrain our understanding of the climate response of the tropical Pacific to increasing greenhouse gases. Due to the lack of continuous ocean observations, proxies become essential to estimate changes in the tropical thermocline related to changes in Walker circulation. Here, we present hig...
Article
Soft corals and black corals are useful proxy tools for paleoceanographic reconstructions. However, most work has focused on deep-water taxa and few studies have used these corals as proxy organisms in shallow water (<200 m). To facilitate the use of stable nitrogen and carbon isotope (δ 15N and δ 13C) records from shallow-water soft coral and blac...
Article
Full-text available
In contrast to the well-studied eastern tropical Pacific Ocean, details of the effects of the El Nino Southern Oscillation (ENSO) on mid-water oceanography in the western tropical Pacific are less well understood and would be enhanced by high resolution, century-scale proxy records. Soft corals and black corals are found in the western tropical Pac...
Article
In this study, time-series stable isotope results (δ13C and δ15N) from three deep-water Leiopathes glaberrima (Esper, 1788) specimens Collected off the southeastern Coast of the United States of America and one specimen from the Gulf of Mexico are presented. The specimens were Collected live in 2004 and are estimated to be 200-500 yrs old based on...
Article
Deep-water gorgonian corals are long-lived and abundant in the North Pacific Ocean. Gorgonians have annually-resolved skeletal organic bands, making them proxies of environmental changes. Specimens of Primnoa sp. were collected from the Gulf of Alaska in 2001, 2003, and 2004. Organic band counts and Pb-210 dating were combined to produce a growth c...
Article
Laser ablation ICP/MS was used to analyze Mg, Sr and U at fine (hundreds of microns) and seasonal spatial scales in the reef coral Porites and the non-photosynthetic ``deep-sea'' corals Lophelia, Oculina, and Desmophyllum. Tropical corals display strong seasonal correlations between Mg, Sr and U, even when normal cycles are perturbed by unknown fac...
Article
Deep-water (307 697 m) antipatharian (black coral) specimens were collected from the southeastern continental slope of the United States and the north-central Gulf of Mexico. The sclerochronology of the specimens indicates that skeletal growth takes place by formation of concentric coeval layers. We used 210Pb to estimate radial growth rate of two...
Chapter
The longest available time series on ocean currents indicates that the southward flow of water from the Greenland Sea is weakening, and that correlative large-amplitude changes have occurred in the rate of formation of intermediate Labrador Sea water. These have been linked to changes in regional climate which, if trends continue, could within 30 y...
Article
"Poor understanding of the nutrient dynamics in the Gulf of Alaska results from insufficient uninterrupted, long-term observations" (PICES, 2004). Failing an instrumental record, oceanographers must increasingly rely on proxies. The utilization of deep-water corals as environmental recorders has only recently been recognized: they may fill in the m...

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