Workshop on the socio-economic effects of marine and fresh water harmful algal blooms in the United States

The US National Office for Harmful Algal Blooms at the Woods Hole Oceanographic Institution (WHOI) and the NOAA National Centers for Coastal Ocean Science (NCCOS) held a virtual workshop comprising four sessions between July 27 and August 5, 2020. This report summarizes the workshop proceedings and presents recommendations developed by participants during the discussion. The recommendations advance an assessment framework and a national research agenda that will lead to comprehensive evaluations of the socio-economic effects of harmful algal blooms (HABs) in fresh water (primarily the Great Lakes) and marine waters of the United States.

Summertime variability of Mediterranean evaporation: competing impacts from the mid latitudes teleconnections and the South Asian monsoon

Interannual variability of Mediterranean evaporation and its links to regional climate during summer are investigated based on evaporation data from the Woods Hole Oceanographic Institution dataset. An EOF (Empirical Orthogonal Function) analysis performed on the monthly means (i.e., separately for June, July, August, and September time series) revealed two leading modes of evaporation variability, characterized by the monopole (EOF-1) and zonal dipole (EOF-2) patterns. These modes explain altogether more than 60% of the total variability of Mediterranean evaporation for each month. In all summer months, the EOF-1 reflects an interdecadal change signal characterized by below normal evaporation in 1970–2000 and above normal evaporation before and after this period. This mode is associated with the Atlantic Multidecadal Oscillation. The EOF-2 pattern reflects interannual variations of Mediterranean evaporation that differ significantly from month to month. The reason for this difference is the changing roles of regional teleconnections, such as the summer North Atlantic Oscillation (SNAO), the Scandinavian and East Atlantic teleconnections, and the Asian monsoon. The impacts of these teleconnections on Mediterranean evaporation are highly variable both in space and time. The largest impact of the SNAO on Mediterranean evaporation is detected in early summer, but its impact weakens and disappears towards the end of the summer season. An opposite tendency is obtained with the Asian monsoon, having the strongest impact on evaporation in late summer. The study suggests that these teleconnections impact Mediterranean evaporation mostly through atmospheric dynamics (the SNAO) and thermodynamics (the Asian monsoon) in early and late summer respectively.

The Northwest Tropical Atlantic Station (NTAS): NTAS-19 Mooring Turnaround Cruise Report Cruise On Board RV Ronald H. Brown October 14 - November 1, 2020

The Northwest Tropical Atlantic Station (NTAS) was established to address the need for accurate air-sea flux estimates and upper ocean measurements in a region with strong sea surface temperature anomalies and the likelihood of significant local air–sea interaction on interannual to decadal timescales. The approach is to maintain a surface mooring outfitted for meteorological and oceanographic measurements at a site near 15°N, 51°W by successive mooring turnarounds. These observations will be used to investigate air–sea interaction processes related to climate variability. This report documents recovery of the NTAS-18 mooring and deployment of the NTAS-19 mooring at the same site. Both moorings used Surlyn foam buoys as the surface element. These buoys were outfitted with two Air–Sea Interaction Meteorology (ASIMET) systems. Each system measures, records, and transmits via Argos satellite the surface meteorological variables necessary to compute air–sea fluxes of heat, moisture and momentum. The upper 160 m of the mooring line were outfitted with oceanographic sensors for the measurement of temperature, salinity and velocity. Deep ocean temperature and salinity are measured at approximately 38 m above the bottom. The mooring turnaround was done on the National Oceanic and Atmospheric Administration (NOAA) Ship Ronald H. Brown, Cruise RB-20-06, by the Upper Ocean Processes Group of the Woods Hole Oceanographic Institution. The cruise took place between 14 October and 1 November 2020. The NTAS-19 mooring was deployed on 22 October, with an anchor position of about 14° 49.48° N, 51° 00.96° W in 4985 m of water. A 31-hour intercomparison period followed, during which satellite telemetry data from the NTAS-19 buoy and the ship’s meteorological sensors were monitored. The NTAS-18 buoy, which had gone adrift on 28 April 2020, was recovered on 20 October near 13° 41.96° N, 58° 38.67° W. This report describes these operations, as well as other work done on the cruise and some of the pre-cruise buoy preparations.

90 years of Arctic Ocean Exploration at the Woods Hole Oceanographic Institution

In 2020, the Woods Hole Oceanographic Institution (WHOI) celebrates 90 years of research, education, and exploration of the World Ocean. Since inception this has included Arctic studies. In fact, WHOI’s first technical report is on the oceanographic data obtained during the submarine “Nautilus” polar expedition in 1931. In 1951 and 1952, WHOI scientists supervised the collection of hydrographic data during the U.S. Navy SkiJump I & II expeditions utilizing ski-equipped aircraft landings in the Beaufort Sea, and inferred the Beaufort Gyre circulation cell and existence of a mid-Arctic ridge. Later classified studies, particularly concerning under-ice acoustics, were conducted by WHOI personnel from Navy and Air Force ice camps. With the advent of simple satellite communications and positioning, WHOI oceanographers began to deploy buoys on sea ice to obtain surface atmosphere, ice, and upper ocean time series data in the central Arctic beginning in 1987. Observations from these first systems were limited technologically to discrete depths and constrained by power considerations, satellite throughput, as well as high costs. As technologies improved, WHOI developed the drifting Ice-Tethered Profiler (ITP) to obtain vertically continuous upper ocean data several times per day in the ice-covered basins and telemeter the data back in near real time to the lab. Since the 1980s, WHOI scientists have also been involved in geological, biological, ecological and geochemical studies of Arctic waters, typically from expeditions utilizing icebreaking vessels, or air supported drifting platforms. Since the 2000s, WHOI has maintained oceanographic moorings on the Beaufort Shelf and in the deep Canada Basin, the latter an element of the Beaufort Gyre Observing System (BGOS). BGOS maintains oceanographic moorings via icebreaker, and conducts annual hydrographic and geochemical surveys each summer to document the Beaufort Gyre freshwater reservoir that has changed significantly since earlier investigations from the 1950s–1980s. With the experience and results demonstrated over the past decades for furthering Arctic research, WHOI scientists are well positioned to continue to explore and study the polar oceans in the decades ahead

The Neutrally Buoyant Sediment Trap: Two Decades of Progress

The biological carbon flux from the ocean’s surface into its interior has traditionally been sampled by sediment traps, which physically intercept sinking particulate matter. However, the manner in which a sediment trap interacts with the flow field around it can introduce hydrodynamic biases, motivating the development of neutral, self-ballasting trap designs. Here, the performance of one of these designs, the neutrally buoyant sediment trap (NBST), is described and evaluated. The NBST has been successfully used in a number of scientific studies since a prototype was last described in the literature two decades ago, with extensive modifications in subsequent years. Originated at Woods Hole Oceanographic Institution, the NBST is built around a profiling float and carries cylindrical collection tubes, a feature that distinguishes it from other neutral traps described in the literature. This paper documents changes to the device that have been implemented over the last two decades, including wider trap tubes; Iridium Communications, Inc., satellite communications; and the addition of polyacrylamide gel collectors and optical sedimentation sensors. Information is also provided with the intent of aiding the development of similar devices by other researchers, including the present adaptation of the concept to utilize commercially available profiling float hardware. The performance of NBSTs built around commercial profiling floats is comparable to NBSTs built around customized floats, albeit with some additional operational considerations. Data from recent field studies comparing NBSTs and traditional, surface-tethered sediment traps are used to illustrate the performance of the instrument design. Potential improvements to the design that remain to be incorporated through future work are also outlined.

Best practices for surface radiation observations from long-term moored buoys

<p>The Upper Ocean Process Group of the Woods Hole Oceanographic Institution deploys moorings with surface buoys instrumented with incoming shortwave and longwave radiometers at locations around the world.  The procedures used to calibrate the radiometers in the laboratory and to assess their performance at sea are discussed.  Some mooring deployments are done during collaborative field experiments and are months to a year in length.  Three other sites are being maintained as long-term Ocean Reference Stations (ORS), with sequential one-year deployments being used to collect ongoing time series.  The Stratus ORS, located under the marine stratus clouds off northern Chile, has been collecting surface radiation observations since 2000.  The NTAS ORS in the western tropical Atlantic has collected surface radiation data since 2001; and the WHOTS ORS north of island of Oahu, Hawaii has collected surface radiation data since 2004.  Challenges encountered in making the surface radiation observations are discussed, and the best estimates of observational uncertainties are presented.  With this understanding of the accuracies of the observations, comparisons between the buoy observations and surface radiation values from models and reanalyses are shown.  Work underway on further improvements to the approaches taken to make surface radiation observations from moored buoy are discussed, and a suggestion for field intercomparisons with other oceanic and land-based surface radiation observing platforms is put forward.</p>

Annotation-free Learning of Plankton for Classification and Anomaly Detection

The acquisition of increasingly large plankton digital image datasets requires automatic methods of recognition and classification. As data size and collection speed increases, manual annotation and database representation are often bottlenecks for utilization of machine learning algorithms for taxonomic classification of plankton species in field studies. In this paper we present a novel set of algorithms to perform accurate detection and classification of plankton species with minimal supervision. Our algorithms approach the performance of existing supervised machine learning algorithms when tested on a plankton dataset generated from a custom-built lensless digital device. Similar results are obtained on a larger image dataset obtained from the Woods Hole Oceanographic Institution. Our algorithms are designed to provide a new way to monitor the environment with a class of rapid online intelligent detectors.Author SummaryPlankton are at the bottom of the aquatic food chain and marine phytoplankton are estimated to be responsible for over 50% of all global primary production [1] and play a fundamental role in climate regulation. Thus, changes in plankton ecology may have a profound impact on global climate, as well as deep social and economic consequences. It seems therefore paramount to collect and analyze real time plankton data to understand the relationship between the health of plankton and the health of the environment they live in. In this paper, we present a novel set of algorithms to perform accurate detection and classification of plankton species with minimal supervision. The proposed pipeline is designed to provide a new way to monitor the environment with a class of rapid online intelligent detectors.