Geology topics

Daniel Pendleton

Publications and source records attributed to Daniel Pendleton.

4 recordsLinked to original sources

USGS2021

Climate impacts on the Gulf of Maine ecosystem: A review of observed and expected changes in 2050 from rising temperatures

The Gulf of Maine has recently experienced its warmest 5-year period (2015–2020) in the instrumental record. This warming was associated with a decline in the signature subarctic zooplankton species, Calanus finmarchicus . The temperature changes have also led to impacts on commercial species such as Atlantic cod ( Gadus morhua ) and American lobster ( Homarus americanus ) and protected species including Atlantic puffins ( Fratercula arctica ) and northern right whales ( Eubalaena glacialis ). The recent period also saw a decline in Atlantic herring ( Clupea harengus ) recruitment and an increase in novel harmful algal species, although these have not been attributed to the recent warming. Here, we use an ensemble of numerical ocean models to characterize expected ocean conditions in the middle of this century. Under the high CO 2 emissions scenario (RCP8.5), the average temperature in the Gulf of Maine is expected to increase 1.1°C to 2.4°C relative to the 1976–2005 average. Surface salinity is expected to decrease, leading to enhanced water column stratification. These physical changes are likely to lead to additional declines in subarctic species including C. finmarchicus , American lobster, and Atlantic cod and an increase in temperate species. The ecosystem changes have already impacted human communities through altered delivery of ecosystem services derived from the marine environment. Continued warming is expected to lead to a loss of heritage, changes in culture, and the necessity for adaptation.

Maine, Massachusetts, New Brunswick, New Hampshire↗

USGS2020

How and why is the timing and occurrence of seasonal migrants in the Gulf of Maine changing due to climate?

Plants and animals undergo certain recurring life-cycle events, such as migrations between summer and winter habitats or the annual blooming of plants. Known as phenology, the timing of these events is very sensitive to changes in climate (and changes in one species’ phenology can impact entire food webs and ecosystems). Shifts in phenology have been described as a “fingerprint” of the temporal and spatial responses of wildlife to climate change impacts. Thus, phenology provides one of the strongest indicators of the adaptive capacity of organisms (or the ability of organisms to cope with future environmental conditions). In this study, researchers are exploring how the timing and occurrence of a number of highly migratory marine animals is changing due to a series of climatic and ecological shifts. First, using existing long-term historical data series, they will determine the direction and magnitude of how migration, abundance, or other phenological factors have changed for marine mammals, sea turtles, and fishes that migrate into the Gulf of Maine on a seasonal basis. Because marine animals are inherently difficult to detect, the team will apply dynamic occupancy models to evaluate seasonal migration patterns and habitat use across multiple habitats in the Gulf of Maine region. The project team will also synthesize regional information on a key, ecologically-important prey fish, sandlance, whose timing and abundance is a strong predictor of the occurrence and behavior of predator species targeted in this study as well as a range of other regional fish and wildlife of conservation and management concern. Results from this component of the project will identify coastal fish and wildlife species that are relatively more or less able to adapt and thus potentially vulnerable to climate change; determine the likely primary drivers of those changes; and identify data gaps and future monitoring needs. Ultimately, this information will be available and useful for regional coastal management and adaptation decisions that will allow managers to effectively plan for the future. In a second component of the project, researchers will focus specifically on changes in migration patterns of the endangered North Atlantic right whale. While shifts in the distribution and time of recurring life events are adaptive responses that may help species cope with climate impacts, they can also lead to changes in how species interact with humans. The North Atlantic right whale is one of the most endangered whale species on the planet. In the North Atlantic Ocean, ship strikes and entanglements with commercial fishing gear represent fatal threats to right whales. Recent reports suggest that North Atlantic right whale migration patterns have changed. Many researchers posit that shifts in migration are responsible for recent increases in the overlap between right whales and human activities, especially fishing. To help understand how changes in right whale movements and behaviors may overlap with ship traffic, and thus put the animals at risk of encountering vessels, we will combine right whale habitat models with ship traffic maps. The end result will be a set of maps identifying risk levels.

Gulf of Maine↗

USGS2019

It’s about time: A synthesis of changing phenology in the Gulf of Maine ecosystem

The timing of recurring biological and seasonal environmental events is changing on a global scale relative to temperature and other climate drivers. This study considers the Gulf of Maine ecosystem, a region of high social and ecological importance in the Northwest Atlantic Ocean and synthesizes current knowledge of 1) key seasonal processes, patterns, and events; 2) direct evidence for shifts in timing; 3) implications of phenological responses for linked ecological-human systems; and 4) potential phenology-focused adaptation strategies and actions. Twenty studies demonstrated shifts in timing of regional marine organisms and seasonal environmental events. The most common response was earlier timing, observed in spring onset, spring and winter hydrology, zooplankton abundance, and diadromous fish migrations. Later timing was documented for fall onset, reproduction and fledging in Atlantic puffins, spring and fall phytoplankton blooms, and occurrence of some larval fishes. Changes in event duration generally increased and were detected in zooplankton peak abundance, early life history periods of macro-invertebrates, and lobster fishery landings. Reduced duration was observed in winter-spring ice-affected stream flows. Two studies projected phenological changes, both finding diapause duration would decrease in zooplankton under future climate scenarios. Phenological responses were species-specific and varied depending on the environmental driver, spatial, and temporal scales evaluated. Overall, a wide range of baseline phenology and relevant modeling studies exist, yet surprisingly few document long-term shifts. Results reveal a need for increased emphasis on phenological shifts in the Gulf of Maine, identify opportunities for future research and consideration of phenological changes in adaptation efforts.

Maine↗

USGS2018

A review of literature for gray and harbor seals

Climate change is impacting marine species, causing shifts in occurrence, distribution, and phenology, which can ultimately effect ecosystem structure and functioning (Parmesan & Yohe 2003; Burrows et al. 2011). The study of the timing of recurring biological events throughout an organism’s life is known as phenology (Parmesan & Yohe 2003). The way organisms respond to climate change through altered timing offers insight into their sensitivity and adaptability (Parmesan & Yohe 2003). To gain an understanding of pinniped vulnerability to climate change, specifically through changes in phenology, a comprehensive literature search was conducted using several online databases (e.g., Web of Science, Google Scholar and PubMed). Combinations of relevant terms were searched in order to find studies pertaining to the life history of two regionally important pinniped species: the gray seal (Halichoerus grypus) and the harbor seal (Phoca vitulina). Although special attention was given to studies conducted in the Northwestern Atlantic region, publications giving information on populations in other parts of the world provided important proxy information. Keyword searches were conducted in Web of Science and Google Scholar and represent the published literature through 2017. The remainder of the publications found were cited in the literature returned from the two searches. This document provides an annotated bibliography organized by species (gray and harbor seals) and region, with topical sections for important attributes (e.g. foraging). The focus of this search was for the Gulf of Maine region, but other relevant information yielded by the literature search is presented in order of approximate distance from the focal area.

Report↗