Walter Adey

Smithsonian Institution · Department of Botany

Long-term, high-resolution measurements of environmental variability are sparse in the High Arctic. In the absence of such data, we turn to proxies recorded in the layered skeletons of the long-lived crustose coralline algae Clathromorphum compactum. Annual growth banding in this alga is dependent on several factors that include temperature, light...

Arctic sea ice cover has been steeply declining since the onset of satellite observations in the late 1970s. However, the available annually resolved sea ice data before this time are limited. Here, we evaluated the suitability of annual trace element (Mg/Ca) ratios and growth increments from the long‐lived annual increment‐forming benthic corallin...

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...

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...

Species of the calcified, articulate coralline Amphiroa are key components of many shallow marine ecosystems. Understanding their mineral composition is important as their susceptibility to dissolution, due to ocean acidification, may vary with mineral composition. We studied the distribution of Mg‐calcite, very high magnesium calcite (VHMC) and do...

This paper describes Sporolithon franciscanum, a new rhodolith-forming species of non-geniculate coralline algae found at depths between 47–52 m near the São Francisco river mouth, the second largest and the most extensive drainage basin in Brazil, and also at the Abrolhos Bank, in the world´s largest rhodolith beds. DNA sequences from plastidial p...

Warming surface ocean temperatures combined with the continued diffusion of atmospheric CO2 into seawater have been shown to have detrimental impacts on calcareous marine organisms in tropical and temperate localities. However, greater oceanic CO2 uptake in higher latitudes may present a higher oceanic acidification risk to carbonate organisms resi...

Research purpose and findings Coralline algae are key biological substrates of many carbonate systems globally. Their capacity to build enduring crusts that underpin the formation of tropical reefs, rhodolith beds and other benthic substrate is dependent on the formation of a calcified thallus. However, this important process of skeletal carbonate...

The organic matrix (OM) contained in marine calcifiers has a key role in the regulation of crystal deposition, such as crystalline structure, initiation of mineralization, inhibition, and biological/environmental control. However, the functional properties of the chitin-rich skeletal organic matrix on the biological aspect of crystallization in cru...

The shallow-marine benthic coralline alga Clathromorphum compactum is an important annual- to sub-annual-resolution archive of Arctic and subarctic environmental conditions, allowing reconstructions going back > 600 years. Both Mg content, in the high-Mg calcitic cell walls, and annual algal growth increments have been used as a proxy for past temp...

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...

The shallow–marine benthic coralline alga Clathromorphum compactum is an important annual to sub-annual resolution archive of Arctic and Subarctic environmental conditions, allowing reconstructions going back > 600 years. Both Mg content, in the high Mg-calcitic cell walls, and annual algal growth increments have been used as a proxy for past tempe...

Humanity is degrading multiple ecosystem services, potentially irreversibly. Two of the most important human impacts are excess agricultural nutrient loading in our fresh and estuarine waters and excess carbon dioxide in our oceans and atmosphere. Large-scale global intervention is required to slow, halt, and eventually reverse these stresses. Cult...

Calcified coralline red algae are ecologically key organisms in photic benthic environments. In recent decades they have become important climate proxies, especially in the Arctic and subarctic. It has been widely accepted that magnesium content in coralline tissues is directly a function of ambient temperature, and this is a primary basis for thei...

A constant effort in sequencing an extensive number of specimens originating from comprehensive sampling had return an unprecedented amount of information fostering our understanding of diversity, evolution and distribution of coralline algae; however, many sequences lack reliable assignation of a taxonomic name, specially at the species level. Rec...

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...

Beds of coralline algal sediment form ecologically and economically important habitats in the North Atlantic. These habitats can occur from the intertidal down to 60 m depth, and they are locally abundant in several countries. Thirteen species of coralline algae form rhodoliths or maerl in this region; Lithothamnion corallioides, L. glaciale, L. to...

The potential of crustose coralline algae as high-resolution archives of past ocean variability in mid- to high-latitudes has only recently been recognized. Few comparisons of coralline algal proxies, such as temperature-dependent algal magnesium to calcium (Mg/Ca) ratios, with in situ-measured surface ocean data exist, even rarer are well replicat...

Warming and acidification of the world's oceans are expected to have widespread consequences for marine biodiversity and ecosystem functioning. However, due to the relatively short record of instrumental observations, one has to rely upon geochemical and physical proxy information stored in biomineralized shells and skeletons of calcareous marine o...

Magnesium content, strongly correlated with temperature, has been developed as a climate archive for the late Holocene without considering anatomical controls on Mg content. In this paper we explore the ultrastructure and cellular scale Mg-content variations within four species of North Atlantic crust-forming Phymatolithon. The cell wall has radial...

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...

Supplementary Figure, Supplementary Note and Supplementary References

Calcified coralline red algae are ecologically key organisms in photic benthic environments. In recent decades they have become important climate proxies, especially in the Arctic and Subarctic. It has been widely accepted that Magnesium content in coralline tissues is directly a function of ambient temperature, and this is a primary basis for thei...

North Atlantic sea surface temperatures experience variability with a periodicity of 60–80 years that is known as the Atlantic Multidecadal Oscillation (AMO). It has a profound imprint on the global climate system that results in a number of high value societal impacts. However the industrial period, i.e. the middle of the 19th century onwards, con...

The Abrolhos Continental Shelf (ACS) encompasses the largest and richest coral reefs in the southern Atlantic Ocean. A taxonomic study of non-geniculate coralline algae (NGCA) from the region was undertaken using both morpho-anatomical and molecular data. Specimens of NGCA were collected in 2012 and 2014 from shallow reefs of the ACS. Phylogenetic...

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...

Considerable research activity has been undertaken to characterize the effects of nutrient cycle changes on the distribution of plant communities in the Florida Everglades. Studies of constructed Everglades ecosystems at the mesocosm scale offer avenues for researching the complexities of these interactions. The objectives of this study were to des...

Plastid-encoded rbcL and psbA sequences from branched, Caribbean Sea Lithophyllum specimens indicate that four species are present, not one. Short (263 base pairs) rbcL sequences from an isolectotype of L. kaiseri (Gulf of Suez) and the holotypes of L. congestum, L. daedaleum and L. platyphyllum (Caribbean Sea) show that L. congestum and L. daedale...

Northern hemisphere rockweeds (Fucus) are thought to have evolved in the North Pacific and then spread to the North Atlantic following the opening of the Bering Strait. They have dispersed and widely speciated in the North Atlantic and its tributary seas. Fucus distichus is likely near the ancestral member of this genus, and studies have shown that...

Map of North America focused on higher latitudes showing the distribution of haplotypes observed (Fig 3) in each oceanic basin with approximate locations, with the exception of Western Pacific locations (Japan). Exact locations for samples are noted in Table 1. (TIF)

Neighbor-joining Tree based on the nrDNA-ITS for Fucus ceranoides, F. distichus, F. evanescens, F. garderni, F serratus, F. spiralis, F. vesiculosus, and F. virsoides specimens from this study and from GenBank (S1 Table). This tree includes several clones (cln_letter) form each plant at each locality we sampled. The tree includes neighbor-joining b...

List of taxa, collector, accession number, and name used in the nrDNA-ITS tree (S2 Fig). Since each of our specimens has several clones, the list of accession number that includes all the clones is provided for each sample locality. More information on longitude, latitude, and sampling location can be verified in Table 1 or in the manuscripts Kucer...

Phymatolithon lusitanicum is a new maerl species described based on an integrative systematic approach including molecular (COI-5P, psbA) and morphological data obtained from recent collections, as well as comparison of type material from the morphologically and ecologically alike NE Atlantic species P. lamii and P. laevigatum. Molecular analyses i...

The aim of this study was to describe the new rhodolith-forming coralline alga species, Sporolithon yoneshigueae sp. nov., based on both morpho-anatomical and molecular data. Specimens were collected in rhodolith beds between 28 and 66 m depths in northeastern and southeastern Brazil. The new species can be distinguished from all other species of t...

DNA sequences from type material in the non-geniculate coralline genus Lithophyllum were used to unambiguously link some European species names to field-collected specimens, thus providing a great advance over morpho-anatomical identification. In particular, sequence comparisons of rbcL, COI and psbA genes from field-collected specimens allowed the...

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...

The rocky, photic benthos of Arctic and Subarctic Biogeographic Regions has a characteristic seaweed flora that includes an extensive high-magnesium calcium carbonate basal layer of crustose coralline red algae. The thickest (10–40 cm) and oldest parts of the crust (previously reported as up to 640–830 years old), primarily at mid-photic depths of...

Coralline red algae demonstrate phenotypic plasticity related to environmental factors, rendering their identification dif- ficult. the cox2-3 spacer is a mitochondrial marker widely used for phylogeographic studies and discrimination between closely related species in red algae; however, cox2-3 spacer sequence data for coralline algae are still li...

For the first time, morpho-anatomical characters that were congruent with DNA sequence data were used to characterize several genera in Hapalidiaceae--the major eco-engineers of Subarctic carbonate ecosystems. DNA sequencing of three genes (SSU, rbcL and psbA), along with patterns of cell division, cell elongation and calcification supported a mono...

As the demand for biofuel products continues to rise along with the need for tertiary wastewater treatment processes to facilitate the removal of phosphorus, increasing importance is placed on the design of cultivation systems for the production of algal biomass. In addition to traditional open ponds and photobioreactors, attached algal growth syst...

In situ Pleistocene reefs form a gently sloping nearshore terrace around the island of Oahu. TIMS Th–U ages of in situ corals indicate that most of the terrace is composed of reefal limestones correlating to Marine Oxygen Isotope Stage 7 (MIS 7, ~ 190–245 ka). The position of the in situ MIS 7 reef complex indicates that it formed during periods wh...

A three-dimensional grid for use as an algal turf growing surface contains a horizontal planar basal net containing a series of horizontal planar members and upwardly directed members.

A new species conforming to the generic description of Sporolithon was found forming small (1–3 cm in diameter) rhodoliths at 18–75 m depth on the eastern coast of Brazil. Sporolithon tenue Bahia, Amado-Filho, Maneveldt et W.H. Adey, sp. nov. differs from other species of Sporolithon in having a thin, primary vegetative thallus of only 45–250 μm in...

Significance The most concerning example of ongoing climate change is the rapid Arctic sea-ice retreat. While just a few years ago ice-free Arctic summers were expected by the end of this century, current models predict this to happen by 2030. This shows that our understanding of rapid changes in the cryosphere is limited, which is largely due to a...

Two Algal Turf Scrubber (ATS) units were deployed on the Great Wicomico River (GWR) for 22months to examine the role of substrate in increasing algal productivity and nutrient removal. The yearly mean productivity of flat ATS screens was 15.4 g center dot m-2 center dot d-1. This was elevated to 39.6g center dot m-2 center dot d-1 with a three-dime...

During the past decades climate and freshwater dynamics in the northwestern North Atlantic have undergone major changes. Large-scale freshening episodes, related to polar freshwater pulses, have had a strong influence on ocean variability in this climatically important region. However, little is known about variability before 1950, mainly due to th...

Coral reef ecosystems develop best in high-flow environments but their fragile frameworks are also vulnerable to high wave energy. Wave-resistant algal rims, predominantly made up of the crustose coralline algae (CCA) Porolithon onkodes and P. pachydermum1, 2, are therefore critical structural elements for the survival of many shallow coral reefs....

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...