Ashley A. Rowden

National Institute of Water and Atmospheric Research and Victoria University of Wellington · Coasts and Oceans Centre, and School of Biological Sciences

Vulnerable Marine Ecosystems (VMEs) are recognised as having high ecological significance and susceptibility to disturbances, including climate change. One approach to providing information on the location and biological composition of these ecosystems, especially in difficult-to-reach environments such as the deep sea, is to generate spatial predi...

Regional Fisheries Management Organisations (RFMOs) use ‘move-on’ rules as one way to manage impacts to vulnerable marine ecosystems (VMEs). In response to a proposal to change the move-on distance from 1 to 5 nm for the South Pacific RFMO, we simulated trawl encounters using historical trawl data and information on the modelled size and spatial cl...

Increasing interest in seabed resource use in the ocean is introducing new pressures on deep‐sea environments, the ecological impacts of which need to be evaluated carefully. The complexity of these ecosystems and the lack of comprehensive data pose significant challenges to predicting potential impacts. In this study, we demonstrate the use of Bay...

Vulnerable marine ecosystems (VMEs) are typically fragile and slow to recover, thereby making them susceptible to disturbance, including fishing. In the high seas, the United Nations General Assembly (UNGA) requested regional fishery management organisations (RFMOs) to implement measures to prevent significant adverse impacts on VMEs. Here, we pred...

Robust impact assessments (IAs) for deep-sea fisheries are essential for safeguarding deep-sea ecosystems against the impacts of bottom fishing. In the high seas, United Nations Resolution commitments require States (inde-pendently or through Regional Fisheries Management Organisations (RFMOs)) to conduct IAs to evaluate if fishing is putting vulne...

Interest in deep seafloor mineral exploitation has been developing over the last few decades, and especially recently as the potential application of metals and elements in these mineral deposits has become more relevant for clean energy technology. The mineral resources located in areas beyond national jurisdiction ("the Area") are under the regul...

Effective ecosystem-based management of bottom-contacting fisheries requires understanding of how disturbances from fishing affect seafloor fauna over a wide range of spatial and temporal scales. Spatial predictions of abundance for 67 taxa were developed, using an extensive dataset of faunal abundances collected using a towed camera system and spa...

Turbidity flows can transport massive amounts of sediment across large distances with dramatic, long-lasting impacts on deep-sea benthic communities. The 2016 M w 7.8 Kaikōura Earthquake triggered a canyon-flushing event in Kaikōura Canyon, New Zealand, which included significant submarine mass wasting, debris, and turbidity flows. This event provi...

In the high seas, regional fishery management organisations are required to implement measures to prevent significant adverse impacts on vulnerable marine ecosystems (VMEs). Our objectives were to develop habitat suitability models for use in the spatial management of bottom fisheries in the South Pacific and to evaluate these and existing models u...

Biogenic habitats are foundational habitats for species assemblages and drive a range of ecosystem functions. The Hauraki Gulf/Tiikapa Moana is the most intensively used coastal area in Aotearoa/New Zealand, and decades of commercial fishing, sedimentation and industrialization have degraded biogenic habitats in the Gulf. In response, the marine sp...

1. The New Zealand Seafloor Community Classification (NZSCC) is a national-scale numerical community classification which depicts compositional turnover of 1716 taxa (demersal fish, reef fish, benthic invertebrates and macroalgae) classified into 75 groups representing seafloor communities. To ensure the continual use of the NZSCC for spatial plann...

Kaikōura Canyon, offshore Aotearoa/New Zealand, is a hotspot for deep-sea benthic biology with globally high faunal abundance. The Mw7.8 Kaikōura earthquake in 2016 triggered a severe disturbance that reshaped the canyon, evacuating an estimated 850 metric megatonnes of sedimentary material down canyon. The Kaikōura Canyon habitat is now recovering...

Vulnerable Marine Ecosystems (VMEs) are recognised as having high ecological significance and susceptibility to disturbances, including climate change. One approach to provide information about these ecosystems, especially in difficult-to-reach environments such as the deep sea, is to generate spatial predictions for VME indicator taxa. In this stu...

The New Zealand region, in the South Pacific, supports a diverse and abundant deep-sea coral fauna. In particular, framework-forming scleractinians that can form reefs can support diverse benthic assemblages. In this chapter, we first set the broader environmental scene by describing the geological and bathymetric setting of the region and its comp...

The impacts of large terrestrial volcanic eruptions are apparent from satellite monitoring and direct observations. However, more than three quarters of all volcanic outputs worldwide lie submerged beneath the ocean, and the risks they pose to people, infrastructure, and benthic ecosystems remain poorly understood due to inaccessibility and a lack...

Aim Deep‐sea hydrothermal vent habitats support a low‐diversity fauna in which most species are unique to the ecosystem. To inform conservation planning around this vulnerable marine ecosystem, we examine species distributions over a wide area to assess the underlying beta‐diversity components and to examine biogeographic patterns. We assess the co...

Increasing interest in seabed resource use in the ocean is introducing new pressures on deep-sea environments, the ecological impacts of which need to be evaluated carefully. The complexity of these ecosystems and the dearth of comprehensive data pose significant challenges to predicting potential impacts. In this study, we demonstrate the use of B...

The study of taxonomy and systematics can enhance ecological and conservation science. However, understanding how taxonomy and systematics can bring about such enhancement is not always readily appreciated. This situation can lead to some ecologists ignoring or dismissing the benefits of working with taxonomists and systematists to achieve their go...

Sediment density flows can transport massive amounts of sediment across large distances and can have dramatic, long-lasting impacts on deep-sea benthic communities. A canyon-flushing event in Kaikōura Canyon, New Zealand, triggered by the 2016 Mw 7.8 Kaikōura Earthquake, which included significant submarine mass wasting, debris and turbidity flows,...

Effective ecosystem-based management of bottom-contacting fisheries requires understanding of how disturbances from fishing affect seafloor fauna over a wide range of spatial and temporal scales. Using an extensive dataset of faunal abundances collected using a towed camera system, with spatially explicit predictor variables including bottom-trawl...

Management of deep-sea fisheries in areas beyond national jurisdiction by Regional Fisheries Management Organizations/Arrangements (RFMO/As) requires identification of areas with Vulnerable Marine Ecosystems (VMEs). Currently, fisheries data, including trawl and longline bycatch data, are used by many RFMO/As to inform the identification of VMEs. H...

The waters around New Zealand are a global hotspot of biodiversity for deep-water corals; approximately one sixth of the known deep-water coral species of the world have been recorded in the region. Deep-water corals are vulnerable to climate-related stressors and from the damaging effects of commercial fisheries. Current protection measures do not...

The waters of Aotearoa New Zealand span over 4.2 million km2 of the South Pacific Ocean and harbour a rich diversity of seafloor-associated taxa. Due to the immensity and remoteness of the area, there are significant gaps in the availability of data that can be used to quantify and map the distribution of seafloor and demersal biodiversity, limitin...

The paper presents spatial predictions of density for 15 VME indicator taxa, based on a data-driven approach using observed abundance data (DTIS); and 4 VME indicator taxa, based on a principles-based approach using expert knowledge. It also presents spatial prediction of relative density for 1 VME indicator taxa based on the vector-autoregressive...

Plain Language Summary Building quantitative proxies that can accurately estimate SSTs is one of the most common themes in paleoceanography. Archeal‐derived hydroxylated isoprenoid glycerol dialkyl glycerol tetraethers (OH‐GDGTs) preserved in marine sediments have a potential to reflect past sea surface temperatures (SSTs). However, the source orga...

Marine habitats and ecosystems are under increasing pressure from human activities. Well-designed Marine Protected Area (MPA) networks can be highly effective tools for conserving biodiversity and associated ecosystem functions and services. Adequate coverage of biogeographic regions -i.e., large regions that represent broad-scale biodiversity patt...

Sediment density flows are large scale disturbances that can have dramatic impacts on seafloor animal communities in the deep sea. Seafloor imagery collected in Kaikōura Canyon (New Zealand), before and after a sediment density flow event that included debris and turbidity flows triggered by a 2016 Mw 7.8 Kaikōura Earthquake, shows the recovery tra...

The waters around New Zealand are a global hotspot of biodiversity for deep-water corals; approximately one sixth of the known deep-water coral species of the world have been recorded in the region. Deep-water corals are vulnerable to climate-related stressors and from the damaging effects of commercial fisheries. Current protection measures do not...

The hitherto monotypic genus Arenallianassa Poore, Dworschak, Robles, Mantelatto and Felder, 2019 is revised following the discovery of a new species, Arenallianassa katrinae sp. nov. from New Zealand and Tonga. The original description of the type species Arenallianassa arenosa (Poore, 1975) is augmented. The new species has been found in localise...

The waters of Aotearoa New Zealand span over 4.2 million km2 of the South Pacific Ocean and harbour a rich diversity of seafloor associated taxa. Due to the immensity and remoteness of the area, there are significant gaps in the availability of data to quantify and map the distribution of seafloor and demersal biodiversity, limiting effective manag...

Marine habitats and ecosystems are under increasing pressure from human activities. Well-designed Marine Protected Area (MPA) networks can be highly effective tools for conserving biodiversity and associated ecosystem functions and services. Adequate coverage of biogeographic regions – i.e., large regions that represent broad-scale biodiversity pat...

The impacts of large terrestrial volcanic eruptions are apparent from satellite monitoring and direct observations 1,2 . However, more than three quarters of all volcanoes worldwide lie submerged beneath the ocean and the risks they pose to people and infrastructure remain poorly understood due to inaccessibility and a lack of detailed observations...

Coralline algae are ecologically important macroalgae providing settlement cues and habitat for a number of marine organisms. They are abundant in a wide range of habitats in tropical to polar systems and are at severe risk from a number of local and global anthropogenic stressors. Despite their ecological importance, there are large gaps in unders...

Hadal trenches are considered to act as depocenters for organic material, although pathways for the material transport and deposition rates are poorly constrained. Here we assess focusing, deposition and accumulation of material and organic carbon in four hadal trench systems underlying different surface ocean productivities; the eutrophic Atacama...

Deep‐water corals are protected in the seas around New Zealand by legislation that prohibits intentional damage and removal, and by marine protected areas where bottom trawling is prohibited. However, these measures do not protect them from the impacts of a changing climate and ocean acidification. To enable adequate future protection from these th...

The intensity of deep-sea fisheries on the high seas and the impacts on the marine environment call for effective measures to ensure that fishing does not compromise the commitments established for protecting biodiversity in the deep ocean by the United Nations. In order to prevent significant adverse impacts (SAIs) on vulnerable marine ecosystems...

Hadal trenches are depocenters for organic material, and host intensified benthic microbial activity. The enhanced deposition is presumed to be reflected in elevated meiofaunal standing-stock, but available studies are ambiguous. Here, we investigate the distribution of meiofauna along the Atacama Trench axis and adjacent abyssal and bathyal settin...

Black carbon is ubiquitous in the marine environment. However, whether it accumulates in the deepest ocean region, the hadal zone, is unknown. Here we measure the concentration and carbon isotopes (δ13C and Δ14C) of black carbon and total organic carbon in sediments from six hadal trenches. Black carbon constituted 10% of trench total organic carbo...

Deep-sea corals are diverse and abundant in New Zealand’s EEZ and the southwest Pacific Ocean. We assessed genetic diversity and gene flow of the deep-sea scleractinian (stony cup coral) Desmophyllum dianthus in five areas (Kermadec Ridge, Louisville Seamount Chain, Chatham Rise, Campbell Plateau, Macquarie Ridge), and applied dispersal kernels est...

This preprint has been submitted to and is under consideration at Journal of Geophysical Research - Biogeosciences. ESSOAr is a venue for early communication or feedback before peer review. Data may be preliminary. Published online: https://doi.org/10.1002/essoar.10510267.1 Hadal trenches act as depocenters for organic material, although pathways...

To support ongoing marine spatial planning in New Zealand, a numerical environmental classification using Gradient Forest models was developed using a broad suite of biotic and high-resolution environmental predictor variables. Gradient Forest modeling uses species distribution data to control the selection, weighting and transformation of environm...

Conducting comprehensive environmental baseline studies is a prerequisite for determining effective environmental management strategies for deep-sea mining. Studies conducted along the Kermadec Volcanic Arc have described biological assemblage structure at multiple spatial scales, connectivity of assemblages at different sites, and functional sensi...

Seamounts are common features of the deep seafloor that are often associated with aggregations of mega-epibenthic fauna, including deep-sea corals and sponges. Globally, many seamounts also host abundant fish stocks, supporting commercial bottom trawl fisheries that impact non-target benthic species through damage and/or removal of these non-target...

The deep sea is subject to multiple anthropogenic disturbances, to which may soon be added mining of hydrothermally-formed seafloor massive sulfides (SMS). As a first step towards a full Ecological Risk Assessment (ERA) for SMS mining, ecological sensitivity to mining activities was assessed based on the functional traits of benthic megafaunal taxa...

Vulnerable marine ecosystems (VMEs) are typically fragile and slow to recover, making them likely to be substantially altered by disturbance. In the High Seas, regional fishery management organizations (RFMOs) are required to implement measures to prevent significant adverse impacts on VMEs. The objectives of the present study were to: update distr...

Knowledge of sedimentary organic carbon (OC) in hadal trenches, the deepest ocean realm, is rudimentary. Here, we conducted a comprehensive analysis of total OC (TOC), stable and radio‐carbon isotopes (δ¹³C and Δ¹⁴C), and biomarkers (e.g., n‐alkanes, n‐alkanols and n‐fatty acids) in 12 sediment cores collected from hadal (trench axis) and non‐hadal...

Methods that predict the distributions of species and habitats by developing statistical relationships between observed occurrences and environmental gradients have become common tools in environmental research, resource management, and conservation. The uptake of model predictions in practical applications remains limited, however, because validat...

Turbidity flows – underwater avalanches – are large-scale physical disturbances that are believed to have profound and lasting impacts on benthic communities in the deep sea, with hypothesized effects on both productivity and diversity. In this review we summarize the physical characteristics of turbidity flows and the mechanisms by which they infl...

Hadal trenches represent the deepest part of the ocean and are dynamic depocenters with intensified prokaryotic activity. Here, we explored the distribution and drivers of prokaryotic and viral abundance from the ocean surface and 40 cm into sediments in two hadal trench regions with contrasting surface productivity. In the water column, prokaryoti...

The deepest part of the global ocean, hadal trenches, are considered to act as depocenters for organic material. Relatively high microbial activity has been demonstrated in the deepest sections of some hadal trenches, but the deposition dynamics are thought to be spatially and temporally variable. Here, we explore sediment characteristics and in-si...

Of the 112+ species of chondrichthyans found in New Zealand waters, approximately 80% of species are found in the deep sea, and many have a high level of data deficiency. Habitat use has been identified as a knowledge gap for deep-sea chondrichthyans, and it is important to understand how different life stages utilise their environment when assessi...

Turbidity flows – underwater avalanches – are large-scale physical disturbances that are believed to have profound and lasting impacts on benthic communities in the deep sea, with hypothesised effects on both productivity and diversity. In this review we summarize the physical characteristics of turbidity flows and the mechanisms by which they infl...

Studies have shown the importance of submarine canyons as conduits of land-derived organic carbon beyond the coastal shelf into the deep-sea where a single obvious river source can be identified. When there is more than one river source, identifying which rivers contribute to canyon sediment organic matter is technically challenging. Here, we compa...

Glycerol dialkyl glycerol tetraethers (GDGTs) have been widely used to elucidate sources of sediment total organic carbon (TOC), past temperature and presence of methanogenesis in diverse environments. However, their applicability to hadal trenches with their unique deposition dynamics remains unknown. Here, we analyzed GDGTs and their stable isoto...

Despite bottom trawling being the most widespread, severe disturbance affecting deep-sea environments, it remains uncertain whether recovery is possible once trawling has ceased. Here, we review information regarding the resilience of seamount benthic communities to trawling. We focus on seamounts because benthic communities associated with these f...