Deep coral habitats of Glacier Bay National Park and Preserve, Alaska

Abstract

Glacier Bay National Park and Preserve (GBNPP) in Southeast Alaska is a system of glaciated fjords with a unique and recent history of deglaciation. As such, it can serve as a natural laboratory for studying patterns of distribution in marine communities with proximity to glacial influence. In order to examine the changes in fjord-based coral communities, underwater photo-quadrats were collected during multipurpose dives with a remotely operated vehicle (ROV) in March of 2016. Ten sites were chosen to represent the geochronological and oceanographic gradients present in GBNPP. Each site was surveyed vertically between 100 and 420 meters depth and photo-quadrats were extracted from the video strip transects for analysis. The ROV was equipped with onboard CTD which recorded environmental data (temperature and salinity), in order to confirm the uniformity of these characteristics at depth across the fjords. The percent cover and diversity of species were lowest near the glaciated heads of the fjords and highest in the Central Channel and at the mouths of the fjords. Diversity is highest where characteristics such as low sedimentation and increased tidal currents are predominant. The diverse communities at the mouths of the fjords and in the Central Channel were dominated by large colonies of the Red Tree Coral, Primnoa pacifica, as well as sponges, brachiopods, multiple species of cnidarians, echinoderms, molluscs and arthropods. The communities at the heads of the fjords were heavily dominated by pioneering species such as brachiopoda, hydrozoan turf, the encrusting stoloniferan coral Sarcodyction incrustans, and smaller colonies of P. pacifica. This research documents a gradient of species dominance from the Central Channel to the heads of the glaciated fjords, which is hypothesized to be driven by a combination of physical and biological factors such as glacial sedimentation, nutrient availability, larval dispersal, and competition.

Shallow-emerged coral may warn of deep-sea coral response to thermal stress

“…Deep-fjord sites-Glacier Bay National Park and Preserve: Gloomy Knob and Central Channel. Glacier Bay is located in the northern inside waters of Southeast Alaska and is a system of glacially derived fjords with two main fjords (the East and West Arms) branching from the Central Channel 10,49 . The bay is strongly influenced by tidewater glaciers, including McBride Glacier in the East Arm, and Johns Hopkins, Margerie, and Lamplugh Glaciers, in the West Arm 10 .…”

“…The bay is strongly influenced by tidewater glaciers, including McBride Glacier in the East Arm, and Johns Hopkins, Margerie, and Lamplugh Glaciers, in the West Arm 10 . The two arms of the fjord join in the main section of the bay known as the Central Channel and the main bay continues out over the terminal moraine through Icy Strait which flows into the eastern GOA 49 . Gloomy Knob is located in the West Arm, 40 km from the head of the fjord 49 .…”

“…The two arms of the fjord join in the main section of the bay known as the Central Channel and the main bay continues out over the terminal moraine through Icy Strait which flows into the eastern GOA 49 . Gloomy Knob is located in the West Arm, 40 km from the head of the fjord 49 . The Central Channel is an area of relatively flat seafloor and is influenced by glacial water from both arms.…”

Panorama mundial das pesquisas com robôs subaquáticos remotamente operados (ROV)

“…Os EUA, Brasil, Reino Unido, França e a Itália são os países que mais investem em pesquisas científicas subaquáticas. Abrangem estudos relacionados à ambientes marinhos estuarinos e apresentam resultados que envolvem áreas tais como biologia, oceanografia, geologia e outras (Lorance & Trenkel, 2006, Linley et al, 2013, Cánovas-Molinaet al, 2016, Carminatto et al, 2020, Hartill al., 2020, Johansen et al, 2020. Todos esses ambientes são constantemente afetados pelo aumento da influência antrópica, principalmente no ambiente marítimo e estuarino com a exploração dos recursos naturais (Hughes et al, 2010, Manoukian et al, 2011.…”