Anthropogenic impacts are increasingly affecting deep‐sea environments, including seafloor sediment disturbances by bottom trawling and seafloor mining. Fieldwork in the ‘Resilience Of Benthic Ecosystems to Sedimentation’ (ROBES) project were conducted in 2018–2020 on the 400 m‐deep Chatham Rise crest, eastern Aotearoa New Zealand. Water column turbidity data, sediment traps on near‐seabed moorings and benthic landers and surf...

Expansion of extractive industries to deep‐sea environments will lead to increased stresses on seafloor ecosystems. We examined changes in environmental parameters following direct and indirect experimental benthic disturbance using a modified plough on the Chatham Rise (∼450 m water depth), Aotearoa/New Zealand. Measurements included sediment community oxygen consumption (SCOC), nutrient fluxes, macro‐infauna community compos...

Growing global demand for deep‐sea resources may lead to increased pressure on benthic ecosystems. Here we examined changes in meiofaunal communities following an in situ physical disturbance experiment. A significant change in meiofaunal community structure in surface (0‐1 cm) and subsurface (1‐5 cm) sediments was observed immediately following the disturbance at both the directly and indirectly disturbed sites and adjacent p...

With the possibility of deep‐sea mining of mineral resources occurring, it is necessary to understand potential impacts on benthic communities. Previous simulated mining experiments revealed direct benthic impacts; however, indirect impacts of sedimentation are not well understood. A disturbance experiment was conducted on Chatham Rise, New Zealand, to assess the resilience of benthic communities to sedimentation that could re...

The marine system plays a critical role in the global climate cycle, as a major control of atmospheric carbon dioxide (CO 2 ). Marine primary production (photosynthesis) and remineralisation of organic carbon (respiration, degradation) determine the amount of CO 2 sequestered in marine sediments and deep‐water environments on century to millennial timescales. The stocks and fluxes of the marine carbon cycle are susceptible to...

The Subtropical Front (STF) and associated biological productivity are topographically locked to the Chatham Rise. Year‐to‐year differences of upper ocean dynamics and associated responses of phytoplankton are valuable for understanding variability in fisheries biomass as well as providing new knowledge of environmental condition for potential seabed mining in this keystone ecosystem. In‐situ observations collected over three...

The Subantarctic Zone of the Southern Ocean plays a disproportionally large role on the Earth system. Model projections predict rapid environmental change in the coming decades, including ocean acidification, warming, and changes in nutrient supply which pose a serious risk for marine ecosystems. Yet despite the importance of the Subantarctic Zone, annual and inter-annual time series are extremely rare, leading to important un...

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 M w 7.8 Kaikōura Earthquake, shows the recovery trajectory of the animal community in the canyon head in the weeks, months, and ye...

Submarine canyons can facilitate the transfer of land‐derived organic matter to the deep sea. Here, we investigated links between variability in organic matter availability from land and marine sources and infauna communities in two contrasting canyon systems off New Zealand and used stable isotope analyses to identify potential food sources of benthic invertebrates. Kaikōura Canyon, a steep, short canyon close to the shore, w...

Macronutrients in sinking phytoplankton are typically remineralized at different rates, but less is known about the fate of micronutrient metals associated with sinking cells. Scavenging, the presence of co‐occurring abiotic particles, and inadvertent contamination limit the utility of bulk analytical approaches to study remineralization of trace metals in sinking phytoplankton. We used synchrotron x‐ray fluorescence mapping t...

In October 2001, we observed a deep‐ocean phytodetritus deposition event on Chatham Rise beneath the Subtropical Front (STF). The origin of this phytodetritus was probably an extensive phytoplankton bloom that occurred in the STF in the preceding weeks. We assessed the spatial distribution of the deposition event using video images from benthic lander and epibenthic trawl deployments and sediment pigment analyses at six sites...

During a survey cruise crossing the Subtropical Front over the Chatham Rise east of New Zealand, we made the first observation in High Nutrient Low Chlorophyll waters of massive sedimentation of picoplankton embedded in large (>0.5 mm diam.) organic aggregates (OAs) sensu Riley (1963). We estimate 9.3 mg C m ‐2 yr ‐1 of prokaryotic picoplankton biomass alone may be transported below the euphotic zone via this mechanism. Using...