Unmanned aerial vehicle based wireless sensor network for marine-coastal environment monitoring

Marine environments are delicate ecosystems which directly influence local climates, flora, fauna, and human activities. Their monitorization plays a key role in their preservation, which is most commonly done through the use of environmental sensing buoy networks. These devices transmit data by means of satellite communications or close-range base stations, which present several limitations and elevated infrastructure costs. Unmanned Aerial Vehicles (UAV) are another alternative for remote environmental monitoring which provide new types of data and ease of use. These aircraft are mainly used in video capture related applications, in its various light spectrums, and do not provide the same data as sensing buoys, nor can they be used for such extended periods of time. The aim of this research is to provide a flexible, easy to deploy and cost-effectiveWireless Sensor Network (WSN) for monitoring marine environments. This proposal uses a UAV as a mobile data collector, low-power long-range communications and sensing buoys as part of a single WSN. A complete description of the design, development, and implementation of the various parts of this system is presented, as well as its validation in a real-world scenario

Water Masses and Circulation in the Tropical Pacific off Central Mexico and Surrounding Areas

13 páginas, 8 figuras, 2 tablasThe seasonal variations and the interactions of the water masses in the tropical Pacific off central Mexico (TPCM) and four surrounding areas were examined based on an extensive new hydrographic database. The regional water masses were redefined in terms of absolute salinity (SA) and conservative temperature (Θ) according to the Thermodynamic Equation of Seawater 2010 (TEOS-10). Hydrographic data and the evaporation minus (precipitation + runoff) balance were used to investigate the origin and seasonality of two salinity minima in the area. The shallow (50–100 m) salinity minimum originates with the California Current System and becomes saltier as it extends southeastward and mixes with tropical subsurface waters while the surface salinity minimum extends farther north in the TPCM in summer and fall because of the northward advection of tropical surface waters. The interactions between water masses allow a characterization of the seasonal pattern of circulation of the Mexican Coastal Current (MCC), the tropical branch of the California Current, and the flows through the entrance of the Gulf of California. The seasonality of the MCC inferred from the distribution of the water masses largely coincides with the geostrophic circulation forced by an annual Rossby waveThis is a product of the project CONACyT (SEP2011–168034-T), with collaboration from the following sources: CONACyT Projects 168034-T, T-9201, 4271P-T, 38797-T, 26653-T, 1076-T9201, 4271PT9601, C01–25343; 38834-T, C02-44870F,G34601-S, and 103898; Naval Postgraduate School; NOC-US; NOAA (GC04– 219); and the regular UABC budget through Projects 4009, 4015, 0324, 0333, and 0352. Funding came from CONACyT, México through the Grant 1329234 for the Ph.D. studies of Esther PortelaPeer reviewe

Fine-Tuning Climate Resilience in Marine Socio-Ecological Systems: The Need for Accurate Space-Time Representativeness to Identify Relevant Consequences and Responses

Climate change triggers a wide mosaic of regional and local responses, often different to the large-scale variability in magnitude and direction. Because of the psychological connections (cognitive and emotional) with the frequency, intensity and age of a climatic event, people may have the capacity to recognize key variations at lower scales, especially those from which they perceive risk. Yet, the anticipatory actions and social engagement to respond or adapt to climate change are difficult to achieve, mostly when there exists a long psychological distance to climatic phenomena. Research about climate change communication provides clues about the relevance of place-based discussion to gauge risk perception and improve response protocols, their design and prioritization. It argues that strategies and actions required to face climate risks may widely differ depending on the scale and accuracy of the local representations displayed during discussions of climate impacts. This work examines how local attributes (from climate to social) operate and control place-specific risks and priorities, by comparing coastal communities in two locations, Cabo Pulmo, Mexico and Zanzibar, Tanzania, which are subject to different climate dynamics. This paper discusses the need to identify relevant climate risks/responses at the local level and how psycho-social factors (e.g., psychological distance, collective memory, and social engagement) may operate positively for building climate resilience. We also illustrate a workflow to increase and enhance collaboration between researchers and local people by promoting dialogue, participation and narratives that rigorously consider the local knowledge

Substrate-induced dimerization of engineered monomeric variants of triosephosphate isomerase from Trichomonas vaginalis

"The dimeric nature of triosephosphate isomerases (TIMs) is maintained by an extensive surface area interface of more than 1600 angstrom 2. TIMs from Trichomonas vaginalis (TvTIM) are held in their dimeric state by two mechanisms: a ball and socket interaction of residue 45 of one subunit that fits into the hydrophobic pocket of the complementary subunit and by swapping of loop 3 between subunits. TvTIMs differ from other TIMs in their unfolding energetics. In TvTIMs the energy necessary to unfold a monomer is greater than the energy necessary to dissociate the dimer. Herein we found that the character of residue I45 controls the dimer-monomer equilibrium in TvTIMs. Unfolding experiments employing monomeric and dimeric mutants led us to conclude that dimeric TvTIMs unfold following a four state model denaturation process whereas monomeric TvTIMs follow a three state model. In contrast to other monomeric TIMs, monomeric variants of TvTIM1 are stable and unexpectedly one of them (I45A) is only 29-fold less active than wild-type TvTIM1. The high enzymatic activity of monomeric TvTIMs contrast with the marginal catalytic activity of diverse monomeric TIMs variants. The stability of the monomeric variants of TvTIM1 and the use of cross-linking and analytical ultracentrifugation experiments permit us to understand the differences between the catalytic activities of TvTIMs and other marginally active monomeric TIMs. As TvTIMs do not unfold upon dimer dissociation, herein we found that the high enzymatic activity of monomeric TvTIM variants is explained by the formation of catalytic dimeric competent species assisted by substrate binding.

ADELIE - Antarctic Drifter Experiment: Links to Isobaths and Ecosystems

The goal of the ADELIE research project is to map, for the first time, the near surface currents around the tip of the Antarctic Peninsula and to determine the role of these currents in the retention or dispersion of krill. Specifically, we will test the hypothesis that pathways to the west near the continent link current systems on the western and eastern sides of the the Peninsula. The influence of bathymetry controlling the splitting and steering of these frontal jets will also be studied. Data for the ADELIE project was collected during cruise JR158. We seek to resolve two important features of the current system around the margin of Antarctica, the Antarctic Slope Front and the Antarctic Coastal Current (see schematic in Figure 1). These currents both flow westward around the continent and are important for the transport of krill, for preconditioning the shelf waters, for the formation of Antarctic Bottom Water, and for supplying waters beneath ice shelves thus melting the underside of the ice shelf. The Antarctic Slope Front defines the boundary between cold, fresh waters filling the Antarctic continental shelf, and the warmer, more saline waters further offshore and is identified by a strong horizontal gradient in temperature and salinity. The Antarctic Coastal Current is a fast, shallow flow over the continental shelf often associated with the front of the ice shelf. The Coastal Current and the Slope Front may merge where the shelf is narrow, but over broad regions of the continental shelf the flows split into two distinct systems. The study area for JR158 is from the tip of the Antarctic Peninsula across the continental shelf and slope to the east and into the deep Weddell Sea (Figure 2). A CTD and Lowered ADCP section were conducted along this transect moving from east to west. This transect was selected to complement the western end of the WOCE SR4 time series, repeated annually by Eberhard Fahrbach and colleagues at the Alfred Wegener Institut (AWI) during the 1990’s. Due to the complexity of the topography in this region, Eulerian measurements at one site are not necessarily representative of the current system a short distance away. Therefore we also deployed surface drifters and Lagrangian floats as a means of tracking the currents. While surface drifters have been successfully released near the Antarctic continent during previous cruises, these drifters provide the first Lagrangian measurements of the current system on the eastern side of the Antarctic Peninsula. New instruments were also tested during JR158 including a microstructure profiler and a dissolved gas mass spectrometer. The microstructure profiler, which is used to resolve smallscale diapycnal mixing, will be used extensively during a mixing study near Kerguelen Island in 2008. The mass spectrometer measures dissolved oxygen/argon ratios that allow estimates of net community production over larger spatial scale with high temporal resolution

ADELIE - Antarctic Drifter Experiment: Links to Isobaths and Ecosystems

The goal of the ADELIE research project is to map, for the first time, the near surface currents around the tip of the Antarctic Peninsula and to determine the role of these currents in the retention or dispersion of krill. Specifically, we will test the hypothesis that pathways to the west near the continent link current systems on the western and eastern sides of the the Peninsula. The influence of bathymetry controlling the splitting and steering of these frontal jets will also be studied. Data for the ADELIE project was collected during cruise JR158. We seek to resolve two important features of the current system around the margin of Antarctica, the Antarctic Slope Front and the Antarctic Coastal Current (see schematic in Figure 1). These currents both flow westward around the continent and are important for the transport of krill, for preconditioning the shelf waters, for the formation of Antarctic Bottom Water, and for supplying waters beneath ice shelves thus melting the underside of the ice shelf. The Antarctic Slope Front defines the boundary between cold, fresh waters filling the Antarctic continental shelf, and the warmer, more saline waters further offshore and is identified by a strong horizontal gradient in temperature and salinity. The Antarctic Coastal Current is a fast, shallow flow over the continental shelf often associated with the front of the ice shelf. The Coastal Current and the Slope Front may merge where the shelf is narrow, but over broad regions of the continental shelf the flows split into two distinct systems. The study area for JR158 is from the tip of the Antarctic Peninsula across the continental shelf and slope to the east and into the deep Weddell Sea (Figure 2). A CTD and Lowered ADCP section were conducted along this transect moving from east to west. This transect was selected to complement the western end of the WOCE SR4 time series, repeated annually by Eberhard Fahrbach and colleagues at the Alfred Wegener Institut (AWI) during the 1990’s. Due to the complexity of the topography in this region, Eulerian measurements at one site are not necessarily representative of the current system a short distance away. Therefore we also deployed surface drifters and Lagrangian floats as a means of tracking the currents. While surface drifters have been successfully released near the Antarctic continent during previous cruises, these drifters provide the first Lagrangian measurements of the current system on the eastern side of the Antarctic Peninsula. New instruments were also tested during JR158 including a microstructure profiler and a dissolved gas mass spectrometer. The microstructure profiler, which is used to resolve smallscale diapycnal mixing, will be used extensively during a mixing study near Kerguelen Island in 2008. The mass spectrometer measures dissolved oxygen/argon ratios that allow estimates of net community production over larger spatial scale with high temporal resolution

Coastal circulation and hydrography in the Gulf of Tehuantepec, Mexico, during winter

16 páginas, 4 tablas, 16 figurasWinter observations of shelf and slope hydrography and currents in the inner Gulf of Tehuantepec are analysed from two field studies in 1989 and 1996 to specify the variability of near-shore conditions under varying wind stress. During the winter period frequent outbursts of ‘Norte’ winds over the central Gulf result in persistent alongshore inflows along both its eastern and western coasts. Wind-induced variability on time scales of several days strongly influences the shelf currents, but has greater effect on its western coast because of the generation and separation of anticyclonic eddies there. The steadier inflow (∼0.2 m s−1) on the eastern shelf is evident in a strong down-bowing of shallow isosurfaces towards the coast within 100 km of shore, below a wedge of warmer, fresher and lighter water. This persistent entry of less saline (33.4–34.0), warmer water from the southeast clearly originates in buoyancy input by rivers along the Central American coast, but is augmented by a general shoreward tendency (0.2 m s−1) in the southeastern Gulf. The resultant shallow tongue of anomalous water is generally swept offshore in the head of the Gulf and mixed away by the strong outflow and vertical overturning of the frequent ‘Norte’ events but during wind relaxations the warm, low-salinity coastal flow may briefly extend further west. In the head of the Gulf, flow is predominantly offshore (<0.2 m s−1) as the alongshore component alternates eastward and westward in association with elevation or depression, respectively, of the pycnocline against the shore. More saline, open ocean water is introduced from the north-western side of the Gulf by the inflow along the west coast. During extended wind relaxations, the flow becomes predominantly eastward beyond the shelf while nearshore the coastally trapped buoyant inflow from the southeast penetrates across the entire head of the gulf at least as far as its western limit. On the basis of these and other recent observations, it seems that the accepted view of a broad, persistent Costa Rica Coastal Current (CRCC) is the result of averaging over many relatively sparse observations and that the instantaneous CRCC is a highly variable and convoluted flow around and between constantly changing eddies. The buoyancy-driven shelf current reported here forms a hitherto unrecognized, but major, component of this CRCC systemField work was supported by NERC (UK), CONACYT (Mexico), PEMEX (Mexico) and ONR (USA). Exchange visits funded by British Council (UK) and MEC (Spain) facilitated writing upPeer reviewe