Warm water temperature regimes in eelgrass beds (Z. marina and Z. japonica) of Padilla Bay, WA

Padilla Bay, WA has over 3300 hectares of eelgrass with vast areas of intermixed beds of the native Zostera marina and non-native Zostera japonica. Water temperature is thought to be one of the primary influences on eelgrass distribution, and long term monitoring shows that temperatures in Padilla Bay have increased substantially (mean increase \u3e2°C) from 2011 through 2016. We were interested to see if changes in eelgrass distribution were correlated with the changes we observed in water temperature in Padilla Bay, however, our long term temperature monitoring station is located in a shallow channel within the eelgrass beds. Because of this sensor placement, we first needed to determine if these data were representative of temperatures experienced by eelgrass on the vegetated flats. To test this, we deployed 45 temperature loggers throughout the intertidal and subtidal distribution of Z. marina and Z. japonica. We found that temperatures recorded at our long term monitoring site greatly underestimated the high temperatures experienced by the intertidal eelgrass. In Padilla Bay, Zostera marina was exposed to temperatures above 8°C, the optimal temperature reported for Z. marina growth in the PNW, for over 90% of the time during the peak growing season (March – Sept.). Furthermore, Z. marina experienced extended periods of time above 15°C, temperatures thought to cause stress to local plants. Despite these elevated temperatures, Z. marina remain robust, suggesting that Z. marina in Padilla Bay may have a higher tolerance for warmer water temperatures than other beds in the PNW or may be living near the upper limits of tolerance for PNW plants. This study characterizes – on a fine spatial scale – the duration and intensity of temperatures extremes that eelgrass experience in shallow systems and ultimately provides insight into the health and performance of eelgrass in a warmer future ocean

Mapping eelgrass (Zostera sp.) habitat in Padilla Bay, WA, using an unmanned aerial system (UAS)

Eelgrass (Zostera marina) monitoring and restoration is important to commercial and ecological management in the Salish Sea. In the southern Salish Sea (Puget Sound, WA), eelgrass distribution overall has not changed in acreage but local eelgrass habitats have declined whereas others have increased. Additionally, coexistence with non-native dwarf eelgrass (Z. japonica) motivates tracking the spatial patterns of change in distribution of both Zostera species on a seasonal and interannual basis. Past efforts to map eelgrass communities have involved the use of satellite imagery and imagery acquired from manned aircraft. Imagery acquired using these platforms typically has a spatial resolution ranging from ~30m to ~1 m. UAS technology offers a new approach to obtain imagery with a spatial resolution of a few centimeters, at very low cost and the image acquisition can be carefully timed to take advantage of low tides. The Padilla Bay National Estuarine Research Reserve (PBNERR) includes one of the largest expanses of eelgrass on the west coast, which has been monitored long-term along permanent transects for Z. marina and Z. japonica coverage, shoot density, and biomass. This provides an ideal setting for the evaluation of alternative methods for mapping eelgrass communities using UAS technology. During the summer of 2017, we collected imagery from a 200 m by 2500 m transect overlapping the permanent plots that make up the PBNERR long-term monitoring transect. We collected imagery using both a multirotor and fixed-wing UAS and two different camera systems with different spectral and spatial resolutions. Here we discuss the logistical challenges of conducting these surveys and present preliminary results of our image classification efforts

Comparison of three pH sensors co-deployed in a high variability environment

Three pH sensors were deployed in a channel in Padilla Bay for several multiple week deployments both in winter and summer seasons. One sensor (a YSI EXO sonde) is part of the long term monitoring of the Padilla Bay National Estuarine Research Reserve. The second sensor is a Satlantic SeaFET, and is part of the Washington Ocean Acidification Center’s monitoring effort. The third sensor is a custom built sensor based on the DuraFET sensor, and identical in design to the suite of sensors in use at the Washington Department of Natural Resources for nearshore monitoring. The sensors were each deployed in individual pvc pipes with large cutouts at the bottom to allow free water flow around the sensor head. The pipes are affixed to a single piling in the bayview channel which drains extensive eelgrass beds. Flow is generally vigorous in the channel and sensors were deployed about 1 meter above the bottom. The pH varies by as much as a full pH unit across a few hours under certain conditions at this location, providing a wide range across which to compare the sensors. The relative performance of these three sensors will be of interest to practitioners wishing to assess data collected with similar sensors across different environments

Long-term monitoring reveals the combined effects of local conditions and large-scale climatic drivers on water quality in a Salish Sea embayment.

Padilla Bay is a shallow embayment north of Puget Sound and one of 28 National Estuarine Research Reserves (NERRs) that have been established as a living laboratory to monitor and research water quality in estuarine ecosystems. An integral part of the Padilla Bay monitoring program is maintaining long-term monitoring stations throughout the bay which provide continuous measurements of water quality parameters. In this presentation we report on over fifteen years of monitoring data and the patterns in temperature and salinity these data have revealed. Our analyses reveal that despite large diel and monthly variability in temperature driven by local environmental conditions in Padilla Bay (i.e. a large, shallow embayment), longer temporal scale patterns appear to be strongly influenced by climatic cycles (e.g., PDO, ENSO). Analysis of surface salinity data during the same time period reveals a general trend from more saline waters in the early 2000’s to fresher conditions in recent years. Surface salinity is also influenced by periodic intrusions of freshwater to Padilla Bay, with discharge data suggesting that both Nooksack and Fraser Rivers play an important role. Our investigation also employs a multivariate classification framework to analyze data from multiple NERRs across the US, identify short- and long-term variability in ocean temperature across these estuaries, and identify how drivers of ocean temperature are unique in waters of the Pacific Northwest (PNW). Not surprisingly, PDO is relatively important in driving surface water temperatures in the PNW relative to east coast estuaries, whereas salinity is less variable. Our analyses provide insight into factors influencing temperature, salinity and other aspects of water quality in the Salish Sea and how these change on multiple spatial and temporal scales

Long term monitoring of eelgrass, water and weather patterns in Padilla Bay, WA.

The importance of eelgrass in nearshore ecosystem function and as an indicator of ecosystem health led to the establishment of a long-term monitoring program focused on tracking annual growth and distribution of eelgrass species (Z. marina and Z. japonica) in Padilla Bay, WA. This annual monitoring program was established in 2011 and consists of 126 permanent plots along three 4 km transects. Eelgrass exhibits a complex response to environmental conditions driven primarily by temperature, light, and nutrients. Optimum growth requirements differ between Z. marina and Z. japonica, with the latter responding positively to warmer water temperatures and possessing an increased tolerance to high temperature extremes (Kaldy et al. 2015). Using long-term monitoring data from Padilla Bay, we investigated factors (i.e. temperature, light availability, water depth) that may help to explain patterns in eelgrass growth and performance. During the study period, we measured a two degree (°C) increase in mean water temperature, an increase in mean surface light (PAR millimoles/m2) and a decrease in mean water depth. Eelgrass measurements over the same time period reveal that the density and biomass of Z. japonica has dramatically increased, while Z. marina density and biomass have fluctuated over time with the lowest observed values in 2015. These data suggest that the predicted increase in local temperature and sea level as a result of climate change may favor expansion of Z. japonica density and distribution, particularly in the upper and mid intertidal. This highlights the importance of evaluating the ecosystem services associated with Z. japonica, and how these compare to Z. marina and other nearshore habitats

Fluctuations in Distribution of a Salish-Sea Eelgrass Meadow Over Time and Space

This presentation will provide methods used to map distributions of eelgrass over time at large and fine scale using ESRI ArcGIS 3D software combined with temporal visualization techniques and Story Maps to facilitate making data accessible to a larger audience. The Padilla Bay National Estuarine Research Reserve uses geospatial technologies in collection, analysis and visualization of its environmental monitoring data. A two-tiered spatial scale eelgrass (Zostera japonica and Zostera marina) monitoring program tracks large scale variability of the intertidal habitats in both time and space on a bay wide scale, as well as fine scale temporal and spatial variation of vegetative characteristics (density, percent cover, and height) annually along three 4-km transects. Aerial photo interpretation, combined with on the ground field data, are used to map distribution bay-wide in 2004 and in 2015, and difference maps between years show where the greatest changes have taken place. The fine scale transect data are visualized using Geographic Information Systems (GIS) animation to look for patterns and relationships, as well as, to identify anomalous events, and use as a visual data screening tool. Collectively, these geospatial visualization tools provide a compelling and captivating means of communicating environmental monitoring data to a wide range of audiences and stakeholders

Large-scale impacts of sea star wasting disease (SSWD) on intertidal sea stars and implications for recovery.

Disease outbreaks can have substantial impacts on wild populations, but the often patchy or anecdotal evidence of these impacts impedes our ability to understand outbreak dynamics. Recently however, a severe disease outbreak occurred in a group of very well-studied organisms-sea stars along the west coast of North America. We analyzed nearly two decades of data from a coordinated monitoring effort at 88 sites ranging from southern British Columbia to San Diego, California along with 2 sites near Sitka, Alaska to better understand the effects of sea star wasting disease (SSWD) on the keystone intertidal predator, Pisaster ochraceus. Quantitative surveys revealed unprecedented declines of P. ochraceus in 2014 and 2015 across nearly the entire geographic range of the species. The intensity of the impact of SSWD was not uniform across the affected area, with proportionally greater population declines in the southern regions relative to the north. The degree of population decline was unrelated to pre-outbreak P. ochraceus density, although these factors have been linked in other well-documented disease events. While elevated seawater temperatures were not broadly linked to the initial emergence of SSWD, anomalously high seawater temperatures in 2014 and 2015 might have exacerbated the disease's impact. Both before and after the onset of the SSWD outbreak, we documented higher recruitment of P. ochraceus in the north than in the south, and while some juveniles are surviving (as evidenced by transition of recruitment pulses to larger size classes), post-SSWD survivorship is lower than during pre-SSWD periods. In hindsight, our data suggest that the SSWD event defied prediction based on two factors found to be important in other marine disease events, sea water temperature and population density, and illustrate the importance of surveillance of natural populations as one element of an integrated approach to marine disease ecology. Low levels of SSWD-symptomatic sea stars are still present throughout the impacted range, thus the outlook for population recovery is uncertain

The Maize Gene terpene synthase 1 Encodes a Sesquiterpene Synthase Catalyzing the Formation of (E)-β-Farnesene, (E)-Nerolidol, and (E,E)-Farnesol after Herbivore Damage

Maize (Zea mays) emits a mixture of volatile compounds upon attack by the Egyptian cotton leafworm (Spodoptera littoralis). These substances, primarily mono- and sesquiterpenes, are used by parasitic wasps to locate the lepidopteran larvae, which are their natural hosts. This interaction among plant, lepidopteran larvae, and hymenopteran parasitoids benefits the plant and has been termed indirect defense. The committed step in the biosynthesis of the different skeletal types of mono- and sesquiterpenes is catalyzed by terpene synthases, a class of enzymes that forms a large variety of mono- and sesquiterpene products from prenyl diphosphate precursors. We isolated a terpene synthase gene, terpene synthase 1 (tps1), from maize that exhibits only a low degree of sequence identity to previously identified terpene synthases. Upon expression in a bacterial system, the encoded enzyme produced the acyclic sesquiterpenes, (E)-β-farnesene, (E,E)-farnesol, and (3R)-(E)-nerolidol, the last an intermediate in the formation of (3E)-4,8-dimethyl-1,3,7-nonatriene. Both (E)-β-farnesene and (3E)-4,8-dimethyl-1,3,7-nonatriene are prominent compounds of the maize volatile blend that is emitted after herbivore damage. The biochemical characteristics of the encoded enzyme are similar to those of terpene synthases from both gymnosperms and dicotyledonous angiosperms, suggesting that catalysis involves a similar electrophilic reaction mechanism. The transcript level of tps1 in the maize cv B73 was elevated after herbivory, mechanical damage, and treatment with elicitors. In contrast, the increase in the transcript level of the tps1 gene or gene homolog in the maize cv Delprim after herbivory was less pronounced, suggesting that the regulation of terpene synthase expression may vary among maize varieties