Heather L Spalding

• PhD
• Assistant Professor at College of Charleston

In 2019, a red macroalgal species, Chondria tumulosa , was discovered overgrowing native coral and algal species and changing the benthic communities of Manawai (Pearl and Hermes Atoll) in Papahānaumokuākea Marine National Monument (PMNM). The main objective of this study was to assess the spatial distribution of C. tumulosa across the forereef and...

Early detection of nuisance species is crucial for managing threatened ecosystems and preventing widespread establishment. Environmental DNA (eDNA) data can increase the sensitivity of biomonitoring programs, often at minimal cost and effort. However, eDNA analyses are prone to errors that can complicate their use in management frameworks. To addre...

The relative rates of sexual versus asexual reproduction influence the partitioning of genetic diversity within and among populations. During range expansions, asexual reproduction often facilitates colonization and establishment. The arrival of the green alga Avrainvillea lacerata has caused shifts in habitat structure and community assemblages si...

The relative rates of sexual versus asexual reproduction influence the partitioning of genetic diversity within and among populations. During range expansions, uniparental reproduction often facilitates colonization and establishment. The arrival of the green alga Avrainvillea lacerata has caused shifts in habitat structure and community assemblage...

In mesophotic coral ecosystems, reef-building corals and their photosynthetic symbionts can survive with less than 1% of surface irradiance. How depth-specialist corals rely upon autotrophically and heterotrophically derived energy sources across the mesophotic zone remains unclear. We analysed the stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope v...

In 2019, a new alga species, Chondria tumulosa, was discovered outcompeting all native coral species and radically changing the benthic ecology of the NWHI. Given the alga's invasive characteristics, the alga poses a potential threat to the ecological structure of the Northwestern Hawaiian Islands and spread to the main Hawaiian Islands. The main o...

Over the last 2 decades, routine collections in the Hawaiian Archipelago have expanded to mesophotic reefs, leading to the discovery of a new red algal genus and species, here described as Anunuuluaehu liula gen. et sp. nov. This study provides a detailed genus and species description and characterizes chloroplast and mitochondrial organellar genom...

The Papahānaumokuākea Marine National Monument, Hawai‘i, is one of the most isolated and protected archipelagos in the world, making it a natural laboratory to examine macroalgal-microbial diversity because of limited direct anthropogenic impacts. We collected the most abundant macroalgae from nine sites ranging from shallow subtidal (1.5 m) to mes...

Two genera of the Rhodymeniales, Halopeltis and Leptofauchea, are here reported for the first time from the Hawaiian Islands and represent the deepest records for both genera. Molecular phylogenetic analyses of cytochrome oxidase subunit I (COI), rbcL, and large subunit ribosomal DNA (LSU) sequences for Hawaiian specimens of Leptofauchea revealed o...

Satellite imagery is a useful tool for monitoring and mapping the distribution of invasive or nuisance algal species on coral reefs over the temporal and spatial scales needed for ecosystem management. Visual inspections of high-resolution satellite imagery were used to detect the newly discovered nuisance alga, Chondria tumulosa, at Manawai (Pearl...

Surveys of Hawaiian macroalgae over the past 15 years have yielded numerous specimens representing species new to science. Calliblepharis yasutakei sp. nov. is here described based on a plant collected at a depth of 98 m from Kapou, Pa-pahânaumokuâkea Marine National Monument, Hawaiʻi. Phylogenetic analyses of three molecular markers (COI, rbcL, an...

Recent investigations into the species diversity of red blades in Hawai‘i have yielded several specimens of Kallymeniaceae from Hawaiian Mesophotic Coral Ecosystems. Our combined morphological and mitochondrial COI-5P and plastid rbcL phylogenetic analyses indicated widespread cryptic diversity among those specimens commonly identified as Kallymeni...

Molecular phylogenetic analyses of Hawaiian members of the red algal family Dumontiaceae were used to clarify the species diversity of Dudresnaya and Gibsmithia from Hawaiʻi. Although no new species of Dudresnaya were detected in the analyses, D. babbittiana is newly recorded by Lalo, Manawai, and Oʻahu; however, this record remains tentative until...

The Hawaiian Archipelago stretches 2500 km from the Main to the Northwestern Hawaiian Islands, represents a complex gradient of oceanographic and anthropogenic drivers, and has a high abundance and diversity of native and invasive macroalgae. These photosynthetic organisms occur in intertidal to mesophotic (30–150+ m) depths and absorb nitrogen wit...

Caribbean coral cover has decreased substantially in recent decades, with much of the live coral being replaced by macroalgae. Encrusting red algae in the genus Ramicrusta have become abundant throughout the region and have demonstrated widespread harm to corals by overgrowing living tissue, causing colony mortality, and impairing coral recruitment...

Two new species, one in the genus Incendia, and one in Seiria, are illustrated and described here from mesophotic peyssonnelioid specimens collected in the Hawaiian Islands based on molecular and morphological analyses. Both genera are reported from Hawai‘i for the first time. Incendia lisianskiensis sp. nov. differs from the other nine described m...

The complete chloroplast genome of Chondria tumulosa, a red alga from Manawai (Pearl and Hermes Atoll), Hawai‘i, was determined and analyzed using next-generation sequencing and de novo assembly approaches. The chloroplast genome sequence of C. tumulosa was 172,617 bp and contained 231 genes, consisting of 197 protein-coding genes, 29 transfer RNA...

Generally, most eukaryotic organisms form relationships with microbes that are important in mediating host organismal health. Macroalgae are a diverse group of photosynthetic eukaryotic organisms that serve as primary producers and foundational species in many ecosystems.

Fifty-six specimens of the red algal genus Martensia from the Main and North-western Hawaiian Islands, representing both shallow (36 specimens from 0–20 m depth) and mesophotic habitats (20 specimens from 62–93 m depth), were collected and characterized using morphological and molecular analyses. Phylogenetic analyses of the rbcL gene resolved five...

The research presented here is a summary of what has been conducted by the University of Hawai'i at Manoa and collaborators since 2014 on the mesophotic coral ecosystems (MCEs) and shallow coral reefs of the Senyavin Islands (Pohnpei Island, and neighbouring atolls Ant and Pakin) in the Federated States of Micronesia (FSM). Annual expeditions have...

This is a lay-summary of a larger report and subsequent book chapter (Rowley et al. 2019), for the local communities and governmental agencies of Pohnpei, Federated States of Micronesia. The research presented is a summary of what has been conducted by the University of Hawai'i at Manoa and collaborators since 2014 on the mesophotic coral ecosystem...

Although the existence of coral-reef habitats at depths to 165 m in tropical regions has been known for decades, the richness, diversity, and ecological importance of mesophotic coral ecosystems (MCEs) has only recently become widely acknowledged. During an interdisciplinary effort spanning more than two decades, we characterized the most expansive...

Raw data from this study Tab 1: Algae Depth Data; Tab 2: Fish Depth Data; Tab 3: NWHI Fish Trophic Data; Tab 4: Temperature Depth Datasets; Tab 5: Temperature Depth Data.

Detailed Materials and Methods

Detailed methods with Track Changes showing alterations from original submission

Picture a coral reef — most people will probably imagine brightly coloured corals, fish and other animals swimming in well-lit shallow waters. In fact, the coral reefs that live close to the surface of the sea — the ones that we can swim, snorkel, or dive near and see from space — are only a small portion of the complete coral reef ecosystem. Light...

Ulvalean algae (Chlorophyta) are most commonly described from intertidal and shallow subtidal marine environments worldwide, but are less well known from mesophotic environments. Their morphological simplicity and phenotypic plasticity make accurate species determinations difficult, even at the generic level. Here, we describe the mesophotic Ulvale...

Mesophotic hard corals (MHC) are increasingly threatened by a growing number of anthropogenic stressors, including impacts from fishing, land-based sources of pollution, and ocean acidification. However, little is known about their geographic distributions (particularly around the Pacific islands) because it is logistically challenging and expensiv...

Despite being one of the simplest metazoans, corals harbor some of the most highly diverse and abundant microbial communities. Differentiating core, symbiotic bacteria from this diverse host-associated consortium is essential for characterizing the functional contributions of bacteria but has not been possible yet. Here we characterize the coral co...

Reef-building corals inhabiting the mesophotic zone (30−150 m) not only survive but thrive in light-limiting environments. Similar to shallow corals, mesophotic corals also exhibit coral fluorescence. Because fluorescent proteins (FPs) absorb high-energy light and emit lower energy light, FPs could play an important role in mesophotic coral physiol...

Corals at the lower limits of mesophotic habitats are likely to have unique photosynthetic adaptations that allow them to persist and dominate in these extreme low light ecosystems. We examined the host–symbiont relationships from the dominant coral genus Leptoseris in mesophotic environments from Hawai‘i collected by submersibles across a depth gr...

Table S1: Detailed Summary Table. Detailed list of collection depths and dates, as well as sampling sites with latitude/longitude coordinates and the coral cover observed around each of the 74 Leptoseris spp. samples investigated in this study. Figure S1: Phylogenetic reconstruction of the coral genus Leptoseris. Best Maximum likelihood (ML) topolo...

Despite its extreme geographical isolation, numerous expeditions have surveyed the marine flora and fauna of Johnston Atoll. However, historical information about the marine biodiversity of Johnston is mostly limited to SCUBA surveys in shallow-waters (<30 m), and submersible observations in deeper waters (100–500 m). Extensive coral reefs, known a...

We provide molecular phylogenetic evidence that the obscure genera Palmophyllum Kütz. and Verdigellas D. L. Ballant. et J. N. Norris form a distinct and early diverging lineage of green algae. These palmelloid seaweeds generally persist in deep waters, where grazing pressure and competition for space are reduced. Their distinctness warrants recogni...

Efforts to map coral reef ecosystems in the Hawaiian Archipelago using optical imagery have revealed the presence of numerous scleractinian, zoothanthellate coral reefs at depths of 30–130+m, most of which were previously undiscovered. Such coral reefs and their associated communities have been recently defined as mesophotic coral ecosystems (MCEs)...

Given the global degradation of shallow-water coral reef ecosystems resulting from anthropogenic activities, mesophotic coral reef ecosystems (MCEs) are gaining attention because they are generally considered a de facto refuge for shallow-water species. Despite their inferred importance, MCEs remain one of the most understudied reef habitats, and b...

This activity familiarizes students with beach erosion, beach health, and the pervasive nature of plastic pollution. Students use measurements of sediment grain size and the buoyancy and density of materials found in beach sand to describe sediment size fraction, determine sand suitability for beach replenishment, and document the relative quantity...

A sampler was developed to collect porewater from permeable (sandy) sediments during manned-submersible operations. The sampler uses vacuum (or atmospheric-pressure) reservoirs to draw porewater into a sediment probe and then into inline sample loops. The sampler is relatively inexpensive, easy to construct, and selfcontained, operating without an...

Extensive deepwater (50-100 m depth) meadows of native and introduced macroalgae occur offshore of the main Hawaiian Islands. Sediment porewater (to 25 cm sediment depth) and overlying seawater were collected during September and December 2004, and November and December 2006 from 13 vegetated and non-vegetated deepwater sites on sand and muddy-sand...

The tropical green algal genus Halimeda is one of the best studied examples of pseudo-cryptic diversity within the algae. Previous molecular and morphometric studies revealed that within Halimeda section Rhipsalis, Halimeda incrassata included three pseudo-cryptic entities and that the morphological boundaries between H. incrassata and Halimeda mel...

We present detailed bathymetry, remotely operated vehicle (ROV) and submersible observations, and sedimentary and radiocarbon age data from carbonate deposits recovered from two submerged terraces at − 150 m (T1) and − 230 m (T2) off Lanai, Hawaii. The tops of the terraces are veneered by relatively thin (< 5 m) in situ accumulations of coralline a...

Palmophyllum, Verdigellas and Palmoclathrus are marine palmelloid green algae with morphologies ranging from closely adherent crusts, peltate discs, to upright branched thalli. Thalli of these taxa are comprised of small spherical cells embedded within a dense mucilaginous matrix. Taxonomic affinities of these palmelloid genera, however, has remain...

The deep-water macroalgal assemblage was described at 14 sites off the central California coast during 1999 and 2000 from SCUBA and remotely operated vehicle sampling. The stipitate kelp Pleurophycus gardneri Setchell & Gardner, previously thought to be rare in the region, was abundant from 30 to 45 m, forming kelp beds below the well-known giant k...

Deepwater macroalgal assemblages (DWAAS) were sampled from 30m to their lower depth limits at 4 locations in central California using enriched air Nitrox and the ROV Ventana. The lowest observed depth limits were 78 m for nongeniculate (encrusting) coralline algae, 58 m for non-calcified red algae (i.e. Maripelta rotata), 40 m for foliose brown alg...