Oceanography | Vol. 38, No. 2
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directly tied to tidal cycles (Mat et al., 2020). Combined, these
findings provide compelling evidence of more direct dynami
cal influences of the surface ocean and the planetary climate on
deep ocean hydrothermal vent ecosystems than was previously
thought. Furthermore, they highlight the importance of long-
term observations supported by the NEPTUNE observatory in
detecting faunal community changes at Endeavour in response
to upper ocean climate variability.
A second seafloor camera installed at Mothra vent field in
2020 is further contributing to our understanding of the tem
poral dynamics of highly mobile and non-vent exclusive ben
thic megafauna, such as zoarcid and macrourid fishes and
decapod crustaceans, by employing machine learning auto
matic classification and counting of the most abundant taxa
(Carter, 2025; Figure 5e). NEPTUNE’s multiple video cam
era platforms, which cover a range of vent habitat types and
incorporate embedded pipelines for automated imagery pro
cessing, can be used to inform MPA managers of long-term
trends in faunal abundance and diversity (Aguzzi et al., 2020;
Ortenzi et al., 2024).
A recent study focused on non-vent benthic megafauna
inhabiting peripheral habitats (e.g., Figure 5f,g) located as
much as a few kilometers away from the main active Endeavour
vent sites. ROV video surveys conducted at Main Endeavour
and High Rise vent fields revealed diverse assemblages domi
nated by slow growing sessile animals, such as rosselid vase
sponges, alcyonacean corals, and crinoids (Neufeld et al., 2022).
A key finding was that corals were nearly absent and rosselid
sponges were found in very low abundances within 25–50 m of
active chimneys but became progressively more abundant and
diverse moving away from the vents; they occurred predomi
nantly at bare basalt ridges and on walls of inactive sulfide chim
neys. Species richness measured using rarefaction curves were
significantly higher at inactive chimneys but never reached
asymptotic values, demonstrating an undersampled and incom
plete species catalogue (Neufeld et al., 2022). These results high
light the importance of studies that consider vent-periphery
habitats covering a wider, landscape-scale habitat heterogene
ity in order to uncover the true ecological “sphere of influence”
(sensu Levin et al., 2016) and the true biodiversity conserva
tion and MPA management value surrounding any hydrother
mal vent system. Furthermore, parallel studies at Endeavour,
such as Georgieva et al. (2020) that investigated microbiomes of
vent-periphery sponges in the genus Spinularia, uncovered puta
tive chemosynthetic Gammaproteobacteria (Thioglobaceae and
Methylomonaceae) directly providing nutrition to the sponges,
indicating that typical non-vent megafauna still benefit from
symbiont associations deriving from dispersed vent fluids in the
surroundings of active hydrothermal sites. Given deep-sea mas
sive sulfide deposit mining activities being proposed for inactive
vent sites around the globe (Jamieson and Gartman, 2020), the
Endeavour Segment, which is protected under the TḥT MPA,
therefore becomes a natural study and monitoring site for fur
ther exploration of the importance of vent-periphery habitats,
biodiversity, and resilience to human impacts.
Photogrammetric mosaics produced by repeated flyovers
using remote or autonomously operated vehicles with dedicated
camera systems (Van Audenhaege et al., 2024) allow monitoring
of ecological dynamics from vent-edifice to centimeter scales.
Motion photogrammetry has been used to generate highly accu
rate habitat terrain models, with high predictive power for faunal
assemblage distribution (Gerdes et al., 2019). The most import
ant community structuring variables in these habitat models
are often distances to diffuse and black fluid exits, as well as the
height of the chimney complex (Gerdes et al., 2019; Girard et al.,
2020). At Endeavour, regular maintenance visits to the obser
vatory with a scientific ROV enabled assembly of a sequence of
3D photogrammetry models from repeat visits to the Mothra
vent field. Data are being analyzed, with preliminary results pro
viding insights into how chimney accretion and erosion affect
spatial distribution and community succession of vent fauna
(Tom Kwasnitschka, GEOMAR Helmholtz Centre for Ocean
Research Kiel, pers. comm., October 22, 2024).
Additionally, ROV survey data (video and navigation) col
lected during observatory maintenance expeditions can be
mined to produce kernel density “heat maps” of significant eco
system components, indicators, and stressors (Juniper et al.,
2019). As the observatory maintenance and operations occur
on a yearly basis, these maps are continuously updated and are
used as essential MPA spatial management tools by quantita
tively assessing research pressure on the vents (e.g., ROV tracks
and sampling efforts), hotspots of biodiversity associated with
vents (typical chemosynthetic communities), and vent periph
ery habitats (e.g., corals and sponges) (Fisheries and Oceans
Canada, 2025). An interactive map is available online with mul
tiple geographical information system (GIS) layers of all obser
vatory maintenance activities, spatial distribution of vent
ing habitat structures (e.g., active and inactive edifices), and
associated biodiversity.
CONCLUSION
Since deployment of scientific instrumentation at the Endeavour
MPA in the fall of 2010, a total of 103 peer-reviewed papers have
been published, as well as 10 dissertations and one book chap
ter (in The Sound of Hydrothermal Vents, Smith and Barclay,
2023). Of the 103 journal articles, 51 were based directly on sen
sor data archived in Oceans 3.0 and/or discrete samples collected
on maintenance expeditions, while 28 articles used ONC data
along with data from other sources (e.g., earthquake, acoustics).
The remaining 24 articles were either review/overview articles
or articles supported by research enabled by ONC. The internet
access and the power offered by the deep-sea observatory pro
moted the development of new hydrothermal vent and seafloor
monitoring technology, while the research resulted in significant