The effect of environmental conditions on the physiological response during a stand-up paddle surfing session

Stand Up Paddleboard (SUP) surfing entails riding breaking waves and maneuvering the board on the wave face in a similar manner to traditional surfing. Despite some scientific investigations on SUP, little is known about SUP surfing. The aim of this study was to investigate the physiological response during SUP surfing sessions and to determine how various environmental conditions can influence this response. Heart rate (HR) of an experienced male SUP surfer aged 43 was recorded for 14.9 h during ten surfing sessions and synced with on board video footage to enable the examination of the effect of different surfing modes and weather conditions on exercise intensity. Results indicated that the SUP surfer’s HR was above 70% of HRmax during 85% of each session, with the greatest heart rates found during falls off the board (~85% HRmax) and while paddling back to the peak (~83% HRmax). Total time surfing a wave was less than 5%, with the majority of time spent paddling back into position. Wind speed positively correlated with HR (r = 0.75, p < 0.05) and wave height negatively correlated with wave caching frequency (r = 0.73, p < 0.05). The results highlight the aerobic fitness for SUP surfing, where wave riding, paddling back to the peak, and falls appear to be associated with the greatest cardiovascular demand and demonstrate that environmental conditions can have an effect on the physiological response during SUP surfing sessions

Sandbar Breaches Control of the Biogeochemistry of a Micro-Estuary

Micro-estuaries in semi-arid areas, despite their small size (shallow depth of a few meters, length of a few kilometers, and a surface area of less than 1 km2) are important providers of ecosystem services. Despite their high abundance, tendency to suffer from eutrophication and vulnerability to other anthropogenic impacts, such systems are among the least studied water bodies in the world. In low tidal amplitude regions, micro-estuaries often have limited rate of sea-river water exchange, somewhat similar to fjord circulation, caused by a shallow sandbar forming at the coastline. The long-term study, we report here was inspired by the idea that, due to their small size and low discharges regime, relatively small interventions can have large effects on micro-estuaries. We used a stationary array of sensors and detailed monthly water sampling to characterize the Alexander estuary, a typical micro-estuary in the S.E. Mediterranean, and to identify the main stress factors in this aquatic ecosystem. The Alexander micro-estuary is stratified throughout the year with median bottom salinity of 18 PSU. Prolonged periods of hypoxia were identified as the main stress factor. Those were alleviated by breaching of the sandbar at the estuary mouth by sea-waves or stormwater runoff events (mostly during winter) that flush the anoxic bottom water. Analysis of naturally occurring sandbar breaches, and an artificial breach experiment indicate that the current oxygen consumption rate of the Alexander micro-estuary is too high to consider sandbar breaches as a remedy for the anoxia. Nevertheless, it demonstrates and provides the tools to assess the feasibility of small-scale interventions to control micro-estuaries hydrology and biogeochemistry

The ecological risk dynamics of pharmaceuticals in micro-estuary environments

Micro-estuarine ecosystems have a surface area < 1 km2 and are abundant in Mediterranean regions. As a result of their small size, these systems are particularly vulnerable to effects of chemical pollution. Due to fluctuating flow conditions of base-flow dominated by treated wastewater effluents and flood events transporting rural and urban non-point-source pollution, micro-estuaries are under a dynamic risk regime, consequently, struggling to provide ecological services. This two-year study explored the occurrence and risks of pharmaceutical contamination in the Alexander micro-estuary in Israel. Pharmaceuticals were detected in all samples (n=280) at as high as 18 µg L-1 in flood events and 14 µg L-1 in base-flow. Pharmaceutical mixtures composition was affected by flow conditions with carbamazepine dominating base-flow and caffeine dominating flood events. Median annual risk quotients for fish, crustaceans and algae were 19.6, 5.2, and 4.5, indicating that pharmaceuticals pose high risk to the ecosystem. Ibuprofen, carbamazepine and caffeine were contribute most to the risk quotients. The current work highlights that micro-estuary ecosystems, like the Alexander estuary, are continuously exposed to pharmaceuticals and most likely to other pollutants, placing these ecologically important systems under an elevated risk, in comparison to the more frequently studied large estuarine systems.  

RGB plots as a tool for the simultaneous visualization of multiple data layers in a two dimensional space.

Visualization of multidimensional data helps in understanding complex systems and environments. We present here a red, green, blue (RGB) visualization method that can serve to display environmental properties. The saturation of each color is used to represent the concentration of a given property. The implementation of that figure is illustrated through visualization of three dissolved inorganic nutrient concentrations along a vertical transect of the Mediterranean, as well as through a vertical time series of three phytoplankton group cell numbers. The RGB figures show well known properties of the water column. In addition, they reveal some lesser-known properties, such as regions in shallow water in which the ratio of phosphorus and silica to nitrogen is high, and a deep eukariotic phytoplankton community. Visualization of such data is usually performed with three separate contour or surface plots, and occasionally two properties are presented as an overlay in a single figure. The RGB figure offers a better way to visualize the interactions among the three separate plots than is commonly available

Single beam bathymetry processed data (Humminbird Helix 10 echosounder entire dataset), Israeli coastal estuaries Lachish, Sorek, Yarkon, Alexander, Taninim and Kishon

We present the data from a bathymetric mapping project in the Israeli coastal estuaries (Lachish, Sorek, Yarkon, Alexander, Taninim and Kishon). The data was collected using a combination of fish finder and GPS operated on a Kayak. The data preperation consisted of: a) manual removal of outliers which were mostly caused by instrument echo in water depths below the instrument 0.5 minimum. b) correction of the mesured water level to the sea level. c) interpolated into regular grid using a terrain following interpolation algorithm. For each of the streams we present the raw measurements, and the interpolated data both as text (csv) file and as GeoTiff file

Vertical RGB time series of phytoplankton taxonomic composition Red, Green, and Blue stands for Eukariotic algae, Synechococcus, and Prochlorococcus respectively as presentedby the color-bar.

<p>Sampling time and depth are indicated by the white dots.</p

Top: RGB figure representing NO₃ (red), PO₄ (green) and, SiOH₄ (blue) concentrations within an eastern Mediterranean transect.

<p>An RGB color scale is presented on the bottom right side with, the red saturation scale (NO₃ concentration) on the Y axis, the green saturation (PO₄ concentration) on the X axis, and a different blue saturation (SiOH₄ concentration) in each rectangle (its value written within rectangles).</p

Map of presented data points.

<p>Nutrient concentration profiles were extracted from the MEDATLAS database <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102903#pone.0102903-Maillard1" target="_blank">[16]</a> along the blue line the plotted on the map to create the RGB nutrient Figure (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102903#pone-0102903-g002" target="_blank">Figure 2</a>). The red asterisk at the eastern coast represents the sampling point for the phytoplankton taxonomic composition, as presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102903#pone-0102903-g004" target="_blank">Figure 4</a>.</p

Bi-weekly surveys of water properties at two marine stations at Alexander micro-estuary

Bi-weekly surveys of water properties at two marine stations ~1 and 6.6 Km from the estuary mouth at bottom depths of 8 and 48 meters. These surveys include water column CTD profiles of temperature, salinity, dissolved oxygen, chlorophyll fluorescence, and Turbidity (OBS). Profile data are accompanied by discrete water samples collected by a Niskin bottle at 10 m depth, these samples are analyzed for the concentrations of chlorophyll-a and pico and nano planktonic algae and non-photosynthetic bacteria

Monthly surveys of water properties along the Alexander micro-estuary

Monthly surveys of water properties along the estuary. These surveys include water column CTD profiles of temperature, salinity, dissolved oxygen, chlorophyll fluorescence, and turbidity (OBS). Profile data are accompanied by Secchi depth measurements and discrete water samples collected by a horizontal Niskin bottle near the surface and near the bottom. Water samples are analyzed for the concentrations of Phosphate, Nitrate, Nitrite, Ammonium, Total and particulate nitrogen and phosphorus, total suspended solids, particulate organic matter, biological oxygen demand, chlorophyll-a, cell counts of nano and pico planktonic algae and non-photosynthetic bacteria